JP2010266408A - Carrier wave type strain measuring device - Google Patents

Carrier wave type strain measuring device Download PDF

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JP2010266408A
JP2010266408A JP2009120250A JP2009120250A JP2010266408A JP 2010266408 A JP2010266408 A JP 2010266408A JP 2009120250 A JP2009120250 A JP 2009120250A JP 2009120250 A JP2009120250 A JP 2009120250A JP 2010266408 A JP2010266408 A JP 2010266408A
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circuit
carrier wave
output
capacitance
bridge
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JP5259488B2 (en
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Shinji Kubodera
眞司 久保寺
Takahiro Hasegawa
高広 長谷川
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Kyowa Electronic Instruments Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To constitute a using circuit with RoSH (Restriction of Hazardous Substances) corresponding component in consideration of also an environmental problem; to cancel always automatically an unbalanced component by a stray capacitance or the like, while reducing a power supply noise; and to measure accurately an actual resistance component following a resistance value change corresponding to a strain gage included in a measuring bridge. <P>SOLUTION: This carrier wave type strain measuring device has a constitution divided into two systems, namely, a primary side circuit system including a measuring bridge 11, an input transformer 12 for inputting output from the bridge 11, a cancellation circuit 14 for correcting the output from the bridge with a fed-back compensation amount, and a primary side power source circuit 18; and a secondary side circuit system including a carrier wave amplifying circuit 21 for generating the compensation amount from the output from the measuring bridge 11, a capacity portion phase detection circuit 23, a capacity portion canceling driving circuit 24, a carrier wave oscillation circuit 26, and a secondary side power source 28. The primary side circuit system and the secondary side circuit system are bonded only through a magnetic bonding means and a light signal transmission means which is an optical bonding means, and do not have an electrical connection part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、搬送波型ひずみ測定装置に係り、より詳しくは、電源ノイズの影響を阻止しつつ、ひずみゲージを含む測定ブリッジに発生する容量不均衡分を常に自動的に打消し得る搬送波型ひずみ測定装置に関するものである。   The present invention relates to a carrier-type strain measurement apparatus, and more particularly, to a carrier-type strain measurement that can automatically cancel out a capacity imbalance generated in a measurement bridge including a strain gauge while preventing the influence of power supply noise. It relates to the device.

従来、ひずみゲージを使用した応力測定には、搬送波型動ひずみ測定装置（以下、「搬送波型ひずみ測定装置」と略称する）が多用されている。その理由は、電源などのハムノイズに原理的に強く、また、測定ブリッジまでの接続配線に接点などを使用しても熱起電力に影響されず、高精度の測定ができるからである。
また、ひずみゲージを使用して応力測定をする場合、ひずみゲージは、小型、軽量であり、測定対象物に殆ど影響を与えないことが最大の特徴である。
一般に、測定点からひずみ測定装置まで入力ケーブルを延長する必要があるが、搬送波型ひずみ測定装置を使用する場合、前記入力ケーブルによる分布容量（浮遊容量とも称される）が生じる。
前記分布容量は、測定ブリッジの抵抗値の初期不平衡値と共に、容量分の初期不平衡値として現れる。ひずみゲージの抵抗変化分は測定に必要なものであるが、容量分は、正確な測定を妨げる要因（測定精度阻害要因）となる。
この容量分に関しては、入力ケーブルの長さ、周囲の温度、湿度などの環境で常時変化する。 Conventionally, a carrier type dynamic strain measuring device (hereinafter, abbreviated as “carrier type strain measuring device”) is frequently used for stress measurement using a strain gauge. The reason is that, in principle, it is strong against hum noise such as a power supply, and even if a contact is used for the connection wiring to the measurement bridge, it is not affected by the thermoelectromotive force, and highly accurate measurement can be performed.
In addition, when measuring stress using a strain gauge, the strain gauge is small and lightweight, and the greatest feature is that it hardly affects the measurement object.
In general, it is necessary to extend an input cable from a measurement point to a strain measuring device. However, when a carrier-type strain measuring device is used, a distributed capacitance (also referred to as stray capacitance) is generated by the input cable.
The distributed capacity appears as an initial unbalance value for the capacity together with an initial unbalance value of the resistance value of the measurement bridge. The change in resistance of the strain gauge is necessary for measurement, but the capacity is a factor that hinders accurate measurement (measurement accuracy impediment factor).
The capacity is constantly changed in the environment such as the length of the input cable, the ambient temperature, and the humidity.

ここで、容量不平衡成分がいかに正確な測定を得ることの阻害となるかについて、図４（ａ）、（ｂ）を用いて説明する。
図４（ａ）は、一般的な搬送波型ひずみ測定装置において、ひずみ測定装置からホィートストンブリッジ回路構成の測定ブリッジに至るまでの回路構成を図式化した説明図であり、（ｂ）は、（ａ）の等価回路図である。
図４（ａ）において、搬送波型ひずみ測定装置８３に、測定ブリッジ８１の固定抵抗Ｒ１，Ｒ２，Ｒ３およびひずみゲージＲ４（測定箇所の抵抗）で構成されるホィートストンブリッジ回路を、入力ケーブル８２で接続した状態を示すものである。ホィートストンブリッジ回路構成の測定ブリッジ８１には、小型、軽量であって、測定対象物の変形に殆ど影響を与えないひずみゲージＲ４が使用されるが、入力ケーブル８２には、分布容量（浮遊容量とも称される）が生じる。この分布容量は、固定抵抗Ｒ１，Ｒ２，Ｒ３およびひずみゲージＲ４からなる測定ブリッジ８１の出力中に、初期不平衡値と共に、容量分の不平衡値としても現れる。このひずみゲージＲ４の抵抗変化分は測定に必要なものであるが、容量分およびその変化は、上述したように、正確な測定を妨げる要因（測定精度阻害要因）となる。 Here, how the capacity imbalance component hinders obtaining an accurate measurement will be described with reference to FIGS.
FIG. 4A is an explanatory diagram schematically illustrating a circuit configuration from a strain measurement device to a measurement bridge having a Wheatstone bridge circuit configuration in a general carrier-type strain measurement device, and FIG. It is an equivalent circuit diagram of (a).
In FIG. 4A, a Wheatstone bridge circuit composed of fixed resistances R1, R2, R3 of the measurement bridge 81 and a strain gauge R4 (resistance at the measurement point) is connected to the carrier-type strain measurement device 83 as an input cable 82. It shows the state connected by. The measuring bridge 81 having the Wheatstone bridge circuit configuration uses a strain gauge R4 that is small and light and has little influence on the deformation of the measurement object, but the input cable 82 has a distributed capacitance (floating). Also referred to as capacitance). This distributed capacity also appears as an unbalanced value for the capacity together with the initial unbalanced value in the output of the measurement bridge 81 composed of the fixed resistors R1, R2, R3 and the strain gauge R4. The resistance change of the strain gauge R4 is necessary for the measurement, but the capacitance and the change are factors that hinder accurate measurement (measurement accuracy impediment factor) as described above.

以下、この測定精度阻害要因についてさらに詳しく分析する。
図４（ａ）に示すひずみ測定装置８３からホィートストンブリッジ回路構成の測定ブリッジ８１までの間の回路構成では、入力ケーブル８２が介在することにより、測定ブリッジ８１の各辺と接地（ＧＮＤ）との間にＣ分が存在する。
測定ブリッジ８１の四辺の抵抗は、Ｒ１〜Ｒ４とし、該四辺のＣ分をＣ１〜Ｃ４とすると図４（ｂ）のような等価回路となる。さらに、測定ブリッジ８１の４辺は、抵抗値Ｒとし、４辺の容量の不平衡分を容量値Ｃａとし、ＧＮＤとの間のＣ分を容量値Ｃｇとすると、図５に示すような等価回路となる。但し、図５に示す等価回路では、Ａ−Ｃ間に搬送波電圧Ｅを印加し、測定ブリッジ８１の出力をＥｏｕｔとしている。
以下の説明では、ＧＮＤとの間のＣ分（即ちＣｇ）は、ＧＮＤとの絶縁が十分であれば、Ｃｇは、無視することができる。
搬送波電圧Ｅの角周波数をωとすると、図５に示す等価回路の出力電圧Ｅｏｕｔは、（１）式で示される。 Hereinafter, this measurement accuracy impeding factor will be analyzed in more detail.
In the circuit configuration between the strain measurement device 83 and the measurement bridge 81 having the Wheatstone bridge circuit configuration shown in FIG. 4A, each side of the measurement bridge 81 and the ground (GND) are interposed by the input cable 82. There is a C minute between
When the resistances of the four sides of the measurement bridge 81 are R1 to R4, and C parts of the four sides are C1 to C4, an equivalent circuit as shown in FIG. Further, assuming that the four sides of the measurement bridge 81 have a resistance value R, an unbalanced portion of the capacitances of the four sides is a capacitance value Ca, and a C portion between the GND and the GND is a capacitance value Cg, an equivalent as shown in FIG. It becomes a circuit. However, in the equivalent circuit shown in FIG. 5, the carrier voltage E is applied between A and C, and the output of the measurement bridge 81 is Eout.
In the following description, Cg can be ignored for the C portion (that is, Cg) with GND if the insulation from GND is sufficient.
If the angular frequency of the carrier voltage E is ω, the output voltage Eout of the equivalent circuit shown in FIG.

Figure 2010266408
また、ひずみ量をεとし、ゲージ率をＫｓとすると、１枚ゲージである場合の等価ブリッジの出力電圧Ｅｏｕｔは、（２）式で示される。
Figure 2010266408
 Further, assuming that the strain amount is ε and the gauge factor is Ks, the output voltage Eout of the equivalent bridge in the case of a single gauge is expressed by equation (2).

Figure 2010266408
（１）式および（２）式から（３）式が得られる。
Figure 2010266408
 Equation (3) is obtained from Equation (1) and Equation (2).

Figure 2010266408
ゲージ率Ｋｓ＝２．００として、（３）式をひずみ量εに関して解くと、（４）式を得る。
Figure 2010266408
 When the gauge factor Ks = 2.00 and the equation (3) is solved with respect to the strain amount ε, the equation (4) is obtained.

Figure 2010266408
さらに、（４）式を実数部と虚数部とに分けると、（５）式に変形される。
Figure 2010266408
 Furthermore, when the expression (4) is divided into a real part and an imaginary part, the expression (5) is transformed.

Figure 2010266408
（５）式において、ａを（６）式、ｂを（７）式と置くと、（８）式を得る。
Figure 2010266408
 In formula (5), if a is set as formula (6) and b is set as formula (7), formula (8) is obtained.

Figure 2010266408
Figure 2010266408

Figure 2010266408
Figure 2010266408

Figure 2010266408
但し、（８）式において、ｃｏｓθ、ｓｉｎθ、およびｚは、それぞれ（９）式で示される。
Figure 2010266408
 However, in the equation (8), cos θ, sin θ, and z are represented by the equation (9), respectively.

Figure 2010266408
Figure 2010266408

（８）式は、位相のずれた正弦波の合成波形の式となることを示している。
以下、等価ブリッジのＣ分の不平衡分（容量値Ｃａ）と、ひずみ量εとの関係を説明する。
図６は、ひずみゲージの抵抗値が１２０Ωの場合と３５０Ωの場合において、それぞれ容量値Ｃａと、ひずみεとの関係を（５）式と（８）式とから求めてグラフで示したグラフ図である。
図６に示すグラフからは、測定ブリッジのＣ分の不平衡分（容量値Ｃａ）が２０００〔ＰＦ〕のとき、ひずみゲージの抵抗値が１２０Ωの場合は約４０００〔μ〕のひずみが測定値として出力されるのに対し、ひずみゲージの抵抗値が３５０Ωの場合には約１１０００〔μ〕ものひずみが測定値として出力されることが理解される。
このように、容量分に関しては、入力ケーブルの長さ、周囲の温度、湿度の他、ひずみゲージの抵抗値によっても大きな影響を受けることが明らかとなった。
ところで、測定ブリッジに容量不平衡分が発生してもそれを打消し得る搬送波型のひずみ測定器として、本件出願人は、特許文献１（特公平２−１６４４１号公報）に記載のひずみ増幅器を先に提案した。
この特許文献１の正弦波搬送波方式のひずみ増幅器は、検出部ブリッジの出力側に該検出部ブリッジの容量変化分に対応する出力成分を抽出する回路と、この回路の出力振幅でブリッジ電源から得た電圧を制御しコンデンサを介して前記検出部ブリッジに帰還する回路とを設け、前記検出部ブリッジに容量Ｃが混入したとき、 Expression (8) indicates that the expression is a composite waveform of a sine wave having a phase shift.
Hereinafter, the relationship between the unbalanced portion of C (capacitance value Ca) of the equivalent bridge and the strain amount ε will be described.
FIG. 6 is a graph showing the relationship between the capacitance value Ca and the strain ε from the equations (5) and (8) when the resistance value of the strain gauge is 120Ω and 350Ω, respectively. It is.
From the graph shown in FIG. 6, when the unbalanced portion (capacitance value Ca) of C of the measurement bridge is 2000 [PF], when the resistance value of the strain gauge is 120Ω, a strain of about 4000 [μ] is measured. However, when the resistance value of the strain gauge is 350Ω, it is understood that a strain of about 11000 [μ] is output as the measured value.
Thus, it has been clarified that the capacity is greatly influenced not only by the length of the input cable, the ambient temperature, and the humidity but also by the resistance value of the strain gauge.
By the way, as a carrier-type strain measuring device capable of canceling even if a capacitance imbalance occurs in the measurement bridge, the applicant of the present application uses the strain amplifier described in Patent Document 1 (Japanese Patent Publication No. 2-16441). Proposed earlier.
The distortion amplifier of the sine wave carrier system of Patent Document 1 is obtained from a bridge power source with an output component corresponding to the capacitance change of the detector bridge on the output side of the detector bridge and an output amplitude of this circuit. And a circuit for controlling the voltage to be fed back to the detection unit bridge via a capacitor, and when a capacitance C is mixed in the detection unit bridge,

Figure 2010266408
なる電圧を前記コンデンサに与える構成とし、検出部ブリッジに容量不平衡分が発生してもそれを完全に打消すことができるようにしたものである。
また、抵抗式ひずみゲージを含むブリッジ回路の初期不平衡の影響を補償しつつ、ブリッジ回路とひずみ測定装置との間の接続線間の浮遊容易などによる位相のずれの影響を補償し、ひずみゲージのひずみに応じた抵抗値変化に伴う実際の抵抗成分を検波するようにした発明として特許文献２（特開２００５−１９５５０９号公報）に記載されたものがある。
Figure 2010266408
 The voltage is applied to the capacitor so that even if a capacitance imbalance occurs in the detection unit bridge, it can be completely canceled.
In addition, while compensating for the initial unbalance effect of the bridge circuit including the resistance type strain gauge, it compensates for the effect of phase shift due to easy floating between the connection lines between the bridge circuit and the strain measuring device. Japanese Patent Application Laid-Open No. 2005-195509 discloses an invention in which an actual resistance component associated with a change in resistance value according to the strain is detected.

この特許文献２に係る発明は、抵抗式ひずみゲージを含むブリッジ回路に交流電源電圧を付与しつつ、該ブリッジ回路の出力電圧信号を交流増幅器に入力して増幅すると共に、該交流増幅器の出力電圧信号から、前記交流電源電圧に対して所定の位相関係を有する信号成分を前記ブリッジ回路の抵抗値変化に応じた抵抗成分として検波し、その検波した抵抗成分から前記ひずみゲージのひずみ値に応じたひずみ測定信号を生成するようにした搬送波型ひずみ測定方法において、
前記ひずみゲージの無ひずみ状態での前記ブリッジ回路の出力電圧信号を前記交流増幅器に入力しつつ、該交流増幅器の出力電圧信号の抵抗成分と該抵抗成分に対して９０°の位相差を有する容量成分とが零になるように該交流増幅器に付加的に入力する初期不平衡補償信号を決定する初期不平衡調整ステップと、
この初期不平衡補償信号の決定後に、前記ブリッジ回路に固定抵抗値の抵抗体を接続して、該ブリッジ回路の出力電圧信号と前記初期不平衡補償信号とを前記交流増幅器に入力しつつ、前記交流増幅器の出力電圧信号の前記交流電源電圧に対する位相のずれ量を決定する位相ずれ決定ステップとを備え、
この位相ずれの決定後に、前記固定抵抗値の抵抗体を前記ブリッジ回路から切り離してひずみ測定を行う時に、前記交流増幅器の出力電圧信号のうち、前記位相ずれ決定ステップで決定したずれ量だけ前記交流電源電圧に対して位相差を有する信号成分を前記ブリッジ回路の抵抗値変化に応じた抵抗成分として検波するようにした搬送波型ひずみ測定方法を提案するものである。 In the invention according to Patent Document 2, an AC power supply voltage is applied to a bridge circuit including a resistance strain gauge, and an output voltage signal of the bridge circuit is input to an AC amplifier to be amplified. A signal component having a predetermined phase relationship with respect to the AC power supply voltage is detected from a signal as a resistance component corresponding to a change in the resistance value of the bridge circuit, and the detected resistance component is used in accordance with a strain value of the strain gauge. In a carrier-type strain measurement method for generating a strain measurement signal,
A capacitor having a phase difference of 90 ° with respect to the resistance component of the output voltage signal of the AC amplifier and the resistance component while inputting the output voltage signal of the bridge circuit in an unstrained state of the strain gauge to the AC amplifier. An initial unbalance adjustment step for determining an initial unbalance compensation signal to be additionally input to the AC amplifier so that the component becomes zero;
After determining the initial unbalance compensation signal, connecting a resistor having a fixed resistance value to the bridge circuit, and inputting the output voltage signal of the bridge circuit and the initial unbalance compensation signal to the AC amplifier, A phase shift determination step for determining a phase shift amount of the output voltage signal of the AC amplifier with respect to the AC power supply voltage,
After the phase shift is determined, when the distortion is measured by separating the resistor having the fixed resistance value from the bridge circuit, the AC voltage is output by the shift amount determined in the phase shift determination step in the output voltage signal of the AC amplifier. A carrier-type distortion measuring method is proposed in which a signal component having a phase difference with respect to a power supply voltage is detected as a resistance component corresponding to a change in the resistance value of the bridge circuit.

特公平２−１６４４１号公報Japanese Patent Publication No. 2-16441 特開２００５−１９５５０９号公報JP 2005-195509 A

上記特許文献１におけるひずみ増幅器では、測定ブリッジや該測定ブリッジに発生する容量成分を打消す容量分打消し回路や１次側電源回路等の１次側回路部分と、搬送波増幅回路、容量分位相検波回路、搬送波発振回路および２次側電源等の回路部分とが、直接電気的に接続されているため電源ノイズがひずみ測定値に影響を与え、Ｓ／Ｎ比が充分とはいえず、さらに高精度での測定の実現が望まれている。
また、特許文献１においては、虚数項検波回路の出力を、ローパスフィルタを介して振幅制御回路に与えて打消し回路を制御するように構成されており、該振幅制御回路は、ローパスフィルタから得られた信号に応じて発光ダイオードを駆動する回路であり、打消し回路は、抵抗と発光ダイオードからの入射光により抵抗値が変化する、例えば、Ｃｄｓセル等のような受光素子との直列回路の両端をブリッジ電源に接続し、前記直列回路の接続点からとり出した信号を増幅器を介して前記コンデレサＣｏに与えるように構成されている。
しかしながら、打消し回路に含まれるＣｄｓは、ＲｏＨＳ（Ｒｅｓｔｒｉｃｔｉｏｎ ｏｆ Ｈａｚａｒｄｏｕｓ Ｓｕｂｓｔａｎｃｅｓ ：危険物質に関する制限の頭文字をとったもの）、即ち「電子・電気機器における特定有害物質の使用制限についての欧州連合による指令」において規制物質に指定されているカドミウムを含有している。 In the distortion amplifier in Patent Document 1, a primary side circuit portion such as a capacitance canceling circuit and a primary side power supply circuit that cancels a capacitance component generated in the measurement bridge and the measurement bridge, a carrier amplifier circuit, a capacitance phase Since circuit portions such as a detection circuit, a carrier wave oscillation circuit, and a secondary power supply are directly connected to each other, power supply noise affects the distortion measurement value, and the S / N ratio is not sufficient. Realization of measurement with high accuracy is desired.
In Patent Document 1, the output of the imaginary term detection circuit is supplied to an amplitude control circuit via a low-pass filter to control the cancellation circuit. The amplitude control circuit is obtained from the low-pass filter. The canceling circuit is a series circuit of a resistor and a light receiving element such as a Cds cell whose resistance value is changed by incident light from the light emitting diode. Both ends are connected to a bridge power supply, and a signal extracted from a connection point of the series circuit is supplied to the condenser Co through an amplifier.
However, the Cds included in the cancellation circuit is RoHS (Restriction of Hazardous Substances), ie, the “European Union Directive on Restriction of Use of Certain Hazardous Substances in Electronic and Electrical Equipment” Contains cadmium which is designated as a regulated substance.

カドミウムは、腎臓に対して、機能障害を起こす恐れがある危険物質であり、１００ｐｐｍ以下（２００７年７月現在）に規制されているため、光電変換素子としてＣｄｓを使用することに問題がある。
また、特許文献２においても、測定ブリッジが含まれる１次側回路部分と、搬送波発振回路、搬送波増幅回路、９０°位相検波回路、９０°位相バランス回路およびこれら回路部分に電源を供給する電源等が電気的に接続されているため、上述したように、電源ノイズが、ひずみ測定値に混入し測定精度を低下させる、という問題がある。
本発明は、上述した事情に鑑みてなされたもので、使用回路は、環境問題にも配慮したＲｏＨＳ対応部品で構成し、電源ノイズの低減を図りつつ、測定ブリッジとひずみ測定回路との間の接続線間の浮遊容量などによる不平衡成分を自動的に打消し、測定ブリッジに含まれるひずみゲージに応じた抵抗値変化に伴う実際の抵抗成分を精度よく測定し得る搬送波型ひずみ測定装置を提供することを目的としている。 Cadmium is a dangerous substance that may cause functional damage to the kidney, and is restricted to 100 ppm or less (as of July 2007), so there is a problem in using Cds as a photoelectric conversion element.
Also in Patent Document 2, a primary side circuit portion including a measurement bridge, a carrier wave oscillation circuit, a carrier wave amplifier circuit, a 90 ° phase detection circuit, a 90 ° phase balance circuit, a power source for supplying power to these circuit portions, etc. Are electrically connected, as described above, there is a problem that power supply noise is mixed into the strain measurement value and the measurement accuracy is lowered.
The present invention has been made in view of the above-described circumstances, and the circuit used is composed of RoHS-compliant components that take environmental problems into consideration, while reducing power supply noise, and between the measurement bridge and the strain measurement circuit. Providing a carrier-type strain measurement device that automatically cancels unbalanced components due to stray capacitance between connecting lines and accurately measures the actual resistance component that accompanies the change in resistance value according to the strain gauge included in the measurement bridge The purpose is to do.

請求項１に記載した発明に係る搬送波型ひずみ測定装置は、上記の目的を達成するために、
搬送波型ひずみ測定装置において、
ひずみゲージを含む測定ブリッジと、
前記測定ブリッジに結合トランスを介して印加する搬送波を発生する搬送波発振回路と、
前記測定ブリッジに印加される搬送波に重畳された測定信号を入力トランスを介して受け増幅する搬送波増幅回路と、
前記搬送波増幅回路の出力を受けて前記測定ブリッジの容量変化分に対応する不平衡成分を抽出し、前記不平衡成分に対応した補償量の信号を出力する容量分位相検波回路と、
少なくとも１つの発光ダイオードとこれと対峙するように配置された受光ダイオードからなる光信号伝達手段と、
前記補償量の信号に応じて前記発光ダイオードの発光輝度を制御する容量分打消し駆動回路と、
前記発光ダイオードの発光を受けて、電気信号に変換する前記受光ダイオードに流れる電流に応じて前記補償量に対応した極性と振幅を持つ補償用電位に変換し、前記極性に応じて出力波形の位相を変えて前記搬送波に前記補償用電位を重畳して前記入力トランスの１次側に供給し、前記測定ブリッジに発生する容量成分による不平衡成分を自動的に打消す容量分打消し回路と、
２次側の各回路に電力を供給する２次側電源と、
前記２次側電源から電力トランスを介して電力を受け、１次側の各回路に電力を供給する１次側電源回路と、
を具備し、
前記搬送波増幅回路、前記容量分位相検波回路、前記容量分打消し駆動回路、前記発光ダイオード、前記搬送波発振回路および前記２次側電源に対し、
前記測定ブリッジ、前記容量分打消し回路、前記受光ダイオードおよび前記１次側電源回路は、
前記入力トランス、前記光信号伝達手段、前記結合トランスおよび前記電力トランスからなる電磁的手段および前記光信号伝達手段により接続され、電気的には絶縁された状態で接続されていることを特徴としている。 In order to achieve the above object, the carrier-type distortion measuring apparatus according to the invention described in claim 1
In a carrier-type strain measuring device,
A measurement bridge including a strain gauge;
A carrier wave oscillation circuit for generating a carrier wave to be applied to the measurement bridge via a coupling transformer;
A carrier amplifier circuit that receives and amplifies a measurement signal superimposed on a carrier wave applied to the measurement bridge via an input transformer;
Receiving the output of the carrier wave amplifier circuit, extracting an unbalanced component corresponding to the capacitance change of the measurement bridge, and outputting a compensation phase signal corresponding to the unbalanced component;
An optical signal transmission means comprising at least one light-emitting diode and a light-receiving diode disposed to face the light-emitting diode;
A capacitance canceling drive circuit for controlling the light emission luminance of the light emitting diode according to the compensation amount signal;
The light emission from the light emitting diode is converted into an electric signal, converted into an electric signal, converted into a compensation potential having a polarity and amplitude corresponding to the compensation amount according to the current flowing through the light receiving diode, and the phase of the output waveform according to the polarity And the compensation potential is superimposed on the carrier wave and supplied to the primary side of the input transformer, and a capacitance canceling circuit for automatically canceling the unbalanced component due to the capacitance component generated in the measurement bridge;
A secondary power supply for supplying power to each circuit on the secondary side;
A primary power supply circuit that receives power from the secondary power supply via a power transformer and supplies power to each circuit on the primary side;
Comprising
For the carrier wave amplification circuit, the capacitance phase detection circuit, the capacitance cancellation drive circuit, the light emitting diode, the carrier wave oscillation circuit, and the secondary power supply,
The measurement bridge, the capacitance canceling circuit, the light receiving diode, and the primary power circuit are:
The input transformer, the optical signal transmission means, the electromagnetic means including the coupling transformer and the power transformer, and the optical signal transmission means are connected to each other and are electrically insulated. .

請求項２に記載した発明に係る搬送波型ひずみ測定装置は、上記の目的を達成するために、
前記光信号伝達手段は、第１の抵抗と第１の発光ダイオードと第２の発光ダイオードと第２の抵抗とよりなる直列回路と、
第１の受光ダイオードと第３の抵抗とからなる直列回路と、第２の受光ダイオードと第４の抵抗とよりなる直列回路とが互いに並列に接続されてなることを特徴としている。
請求項３に記載した発明に係る搬送波型ひずみ測定装置は、上記の目的を達成するために、
前記容量分打消し回路は、前記光信号伝達手段の前記第１の受光ダイオードと前記第３の抵抗との接続点電位と、前記第２の受光ダイオードと前記第４の抵抗との接続点電位とを比較して前記補償量の電位と極性を判定し、出力波形の振幅と位相を決定して出力するように構成されていることを特徴としている。 In order to achieve the above object, a carrier-type distortion measuring apparatus according to the invention described in claim 2
The optical signal transmission means includes a first circuit including a first resistor, a first light emitting diode, a second light emitting diode, and a second resistor.
A series circuit composed of a first light receiving diode and a third resistor and a series circuit composed of a second light receiving diode and a fourth resistor are connected in parallel to each other.
In order to achieve the above object, a carrier wave distortion measuring apparatus according to the invention described in claim 3
The capacitance canceling circuit includes a connection point potential between the first light receiving diode and the third resistor of the optical signal transmission means, and a connection point potential between the second light receiving diode and the fourth resistor. And determining the potential and polarity of the compensation amount, and determining and outputting the amplitude and phase of the output waveform.

請求項４に記載した発明に係る搬送波型ひずみ測定装置は、上記の目的を達成するために、
特定の１つまたは複数の較正値に対応する較正電圧を発生する較正値発生回路の出力を、前記搬送波に重畳して前記入力トランスの１次側に選択的に供給し得るように構成されていることを特徴としている。
請求項５に記載した発明に係る搬送波型ひずみ測定装置は、上記の目的を達成するために、
前記測定ブリッジの抵抗値の初期不平衡分を打消す電位を発生する抵抗分調整回路の出力を、前記搬送波に重畳して前記入力トランスの１次側に常時供給するように構成されていることを特徴としている。 In order to achieve the above object, a carrier wave distortion measuring apparatus according to the invention described in claim 4
An output of a calibration value generating circuit that generates a calibration voltage corresponding to one or more specific calibration values is configured to be selectively supplied to the primary side of the input transformer superimposed on the carrier wave. It is characterized by being.
In order to achieve the above object, a carrier wave distortion measuring apparatus according to the invention described in claim 5
The output of a resistance adjustment circuit that generates a potential that cancels the initial unbalance of the resistance value of the measurement bridge is configured to be constantly supplied to the primary side of the input transformer, superimposed on the carrier wave. It is characterized by.

本発明の請求項１の搬送波型ひずみ測定装置によれば、
搬送波型ひずみ測定装置において、
ひずみゲージを含む測定ブリッジと、
前記測定ブリッジに結合トランスを介して印加する搬送波を発生する搬送波発振回路と、
前記測定ブリッジに印加される搬送波に重畳された測定信号を入力トランスを介して受け増幅する搬送波増幅回路と、
前記搬送波増幅回路の出力を受けて前記測定ブリッジの容量変化分に対応する不平衡成分を抽出し、前記不平衡成分に対応した補償量の信号を出力する容量分位相検波回路と、
少なくとも１つの発光ダイオードとこれと対峙するように配置された受光ダイオードからなる光信号伝達手段と、
前記補償量の信号に応じて前記発光ダイオードの発光輝度を制御する容量分打消し駆動回路と、
前記発光ダイオードの発光を受けて、電気信号に変換する前記受光ダイオードに流れる電流に応じて前記補償量に対応した極性と振幅を持つ補償用電位に変換し、前記極性に応じて出力波形の位相を変えて前記搬送波に前記補償用電位を重畳して前記入力トランスの１次側に供給し、前記測定ブリッジに発生する容量成分による不平衡成分を自動的に打消す容量分打消し回路と、
２次側の各回路に電力を供給する２次側電源と、
前記２次側電源から電力トランスを介して電力を受け、１次側の各回路に電力を供給する１次側電源回路と、
を具備し、
前記搬送波増幅回路、前記容量分位相検波回路、前記容量分打消し駆動回路、前記発光ダイオード、前記搬送波発振回路および前記２次側電源に対し、
前記測定ブリッジ、前記容量分打消し回路、前記受光ダイオードおよび前記１次側電源回路は、
前記入力トランス、前記光信号伝達手段、前記結合トランスおよび前記電力トランスからなる電磁的手段および前記光信号伝達手段により接続され、電気的には絶縁された状態で接続されているので、ＲｏＨＳ指令の特定有害物質に指定された有害物質であるカドミウムを含むＣｄｓを用いることなく光信号伝達手段として発光ダイオードと受光ダイオードを用いることで、リサイクルを容易にし、また、最終的に埋立てや焼却処分されるときに、ヒトと環境に影響を与えずに済み、
さらには、測定ブリッジが出力側（２次側）と絶縁されていることによる電源ノイズの低減と高電位な場所でのひずみ測定を可能としつつ、併せて、測定ブリッジに生じる容量不平衡分を常時完全に打消し得る搬送波型ひずみ測定装置を提供することができる。 According to the carrier distortion measuring apparatus of claim 1 of the present invention,
In a carrier-type strain measuring device,
A measurement bridge including a strain gauge;
A carrier wave oscillation circuit for generating a carrier wave to be applied to the measurement bridge via a coupling transformer;
A carrier amplifier circuit that receives and amplifies a measurement signal superimposed on a carrier wave applied to the measurement bridge via an input transformer;
Receiving the output of the carrier wave amplifier circuit, extracting an unbalanced component corresponding to the capacitance change of the measurement bridge, and outputting a compensation phase signal corresponding to the unbalanced component;
An optical signal transmission means comprising at least one light-emitting diode and a light-receiving diode disposed to face the light-emitting diode;
A capacitance canceling drive circuit for controlling the light emission luminance of the light emitting diode according to the compensation amount signal;
The light emission from the light emitting diode is converted into an electric signal, converted into an electric signal, converted into a compensation potential having a polarity and amplitude corresponding to the compensation amount according to the current flowing through the light receiving diode, and the phase of the output waveform according to the polarity And the compensation potential is superimposed on the carrier wave and supplied to the primary side of the input transformer, and a capacitance canceling circuit for automatically canceling the unbalanced component due to the capacitance component generated in the measurement bridge;
A secondary power supply for supplying power to each circuit on the secondary side;
A primary power supply circuit that receives power from the secondary power supply via a power transformer and supplies power to each circuit on the primary side;
Comprising
For the carrier wave amplification circuit, the capacitance phase detection circuit, the capacitance cancellation drive circuit, the light emitting diode, the carrier wave oscillation circuit, and the secondary power supply,
The measurement bridge, the capacitance canceling circuit, the light receiving diode, and the primary power circuit are:
Since the input transformer, the optical signal transmission means, the electromagnetic means including the coupling transformer and the power transformer and the optical signal transmission means are connected and electrically connected, the RoHS command By using light-emitting diodes and light-receiving diodes as optical signal transmission means without using Cds containing cadmium, which is a hazardous substance designated as a specific hazardous substance, it is easy to recycle, and finally it is landfilled or incinerated. When you do not have to affect the human and the environment,
Furthermore, while the measurement bridge is insulated from the output side (secondary side), it is possible to reduce power supply noise and measure strain at high potentials. It is possible to provide a carrier-type distortion measuring apparatus that can be completely canceled at all times.

本発明の第１の実施形態に係る搬送波型ひずみ測定装置の全体回路構成を示す回路図である。It is a circuit diagram which shows the whole circuit structure of the carrier wave type | mold distortion measuring apparatus which concerns on the 1st Embodiment of this invention. 本発明の第２の実施形態に係る搬送波型ひずみ測定装置における光信号伝達手段と打消し回路の詳細構成と、その間の配線および容量分打消し駆動回路との配線を示す回路図である。It is a circuit diagram which shows the detailed structure of the optical signal transmission means and cancellation circuit in the carrier-wave type | mold distortion measuring apparatus which concerns on the 2nd Embodiment of this invention, the wiring between them, and the wiring with a capacity | capacitance cancellation drive circuit. 打消し回路からの出力電圧（補償量）を帰還するための具体的な回路接続を示す回路図である。It is a circuit diagram which shows the concrete circuit connection for returning the output voltage (compensation amount) from a cancellation circuit. （ａ）は、一般的な搬送波型ひずみ測定装置において、測定装置からホィートストンブリッジ回路構成の測定ブリッジに至るまでの回路構成を図式化した説明図であり、（ｂ）は、（ａ）の等価回路図である。(A) is explanatory drawing which schematized the circuit structure from a measuring apparatus to the measurement bridge | bridging of a Wheatstone bridge circuit structure in a general carrier wave type | mold distortion measuring apparatus, (b) is (a). FIG. 図４（ｂ）における抵抗Ｒ１〜Ｒ４の抵抗値をＲとし、４辺のＣ分の不平衡分をＣａとし、グラウンド間のＣ分をＣｇとしたとき、の等価回路図である。FIG. 5B is an equivalent circuit diagram when the resistance values of the resistors R1 to R4 in FIG. 4B are R, the unbalanced portion of C on the four sides is Ca, and the C portion between the grounds is Cg. ひずみゲージの抵抗値が１２０Ωの場合と３５０Ωの場合における、それぞれ容量値Ｃａと、ひずみ量εとの関係をグラフで示したグラフ図である。It is the graph which showed the relationship between capacitance value Ca and strain amount (epsilon) in the case where the resistance value of a strain gauge is 120 ohms and 350 ohms, respectively.

以下、本発明の搬送波型ひずみ測定装置の第１の実施形態について、図面を参照して詳細に説明する。
図１は、本発明の第１の実施形態に係る搬送波型ひずみ測定装置全体の回路構成を示す回路図である。
同図において、本実施形態の搬送波型ひずみ測定装置は、ひずみゲージをもって構成されたホイートストンブリッジ回路（以下、「測定ブリッジ」と略称する）１１と、該測定ブリッジ１１の出力を後述する帰還された補償量で補正する回路とから成る１次側回路系統（以下、「１次側」と略称する）と、該測定ブリッジ１１の出力から前記補償量を生成する補償量検出回路を有する２次側回路系統（以下、「２次側」と略称する）とに分けられる。１次側と２次側は、磁気的な結合手段、例えば、入力トランス１２、結合トランス１９、電力トランス２０と光学的な結合手段、例えば、光信号伝達手段１３とを介してのみ結合され、電気的に直接接続されていない。 Hereinafter, a first embodiment of a carrier wave distortion measuring apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a circuit diagram showing a circuit configuration of the entire carrier-type distortion measuring apparatus according to the first embodiment of the present invention.
In the figure, the carrier-type strain measuring device of the present embodiment is a Wheatstone bridge circuit (hereinafter abbreviated as “measurement bridge”) 11 configured with a strain gauge, and the output of the measurement bridge 11 is fed back as will be described later. A secondary side having a primary circuit system (hereinafter abbreviated as “primary side”) composed of a circuit for correcting with a compensation amount and a compensation amount detection circuit for generating the compensation amount from the output of the measurement bridge 11 It is divided into a circuit system (hereinafter abbreviated as “secondary side”). The primary side and the secondary side are coupled only via magnetic coupling means, for example, input transformer 12, coupling transformer 19, power transformer 20, and optical coupling means, for example, optical signal transmission means 13, Not electrically connected directly.

まず、１次側として、ホイートストンブリッジ回路で構成されている測定ブリッジ１１と、測定ブリッジ１１の出力を受けて磁気結合により２次側に伝える入力トランス１２（１次コイル）と、光信号伝達手段１３を構成する受光ダイオード１３ｂ側と、測定ブリッジ１１に入力する搬送波をリファレンス電圧として受けて補償量に比例した電圧値で変調した電圧値を入力トランス１２に帰還（注入）する打消し回路１４と、測定ブリッジ１１に入力する搬送波と同じ搬送波を受けて打消し回路１４にリファレンス電圧を供給するＢ．Ｖ波形供給回路１５が含まれる。
さらに、１次側には、特定の１または複数の較正値を搬送波に重畳して入力トランス１２に供給する較正値発生回路１６と、無ひずみ状態において、測定ブリッジ１１の出力に含まれる抵抗分の初期平衡成分による誤差を調整する電圧を搬送波に重畳させて入力トランス１２に注入する抵抗分調整回路１７と、１次側の回路が使用する電力を供給する１次側電源回路１８と、２次側の搬送波（この場合、正弦波）発振回路としての発振回路２６から出力される搬送波を測定ブリッジ１１に伝達する結合トランス１９（２次コイル）と、２次側のパワーアンプ回路２７から出力される搬送波の電力を受けて、１次側電源回路１８に伝達する電力トランス２０（２次コイル）と、を備える。 First, as a primary side, a measurement bridge 11 composed of a Wheatstone bridge circuit, an input transformer 12 (primary coil) that receives the output of the measurement bridge 11 and transmits it to the secondary side by magnetic coupling, and optical signal transmission means And a cancellation circuit 14 that receives a carrier wave input to the measurement bridge 11 as a reference voltage and feeds back (injects) a voltage value modulated by a voltage value proportional to the compensation amount to the input transformer 12. B. Supplying a reference voltage to the cancellation circuit 14 upon receiving the same carrier wave as that input to the measurement bridge 11 A V waveform supply circuit 15 is included.
Further, on the primary side, a calibration value generating circuit 16 that superimposes specific one or a plurality of calibration values on a carrier wave and supplies the input transformer 12 and a resistance component included in the output of the measurement bridge 11 in a non-distortion state. A resistance adjustment circuit 17 that superimposes a voltage for adjusting an error due to the initial equilibrium component on the carrier wave and injects it into the input transformer 12, a primary side power supply circuit 18 that supplies power used by the primary side circuit, and 2 A coupling transformer 19 (secondary coil) that transmits a carrier wave output from the oscillation circuit 26 as a secondary side carrier wave (in this case, a sine wave) oscillation circuit to the measurement bridge 11 and an output from the power amplifier circuit 27 on the secondary side A power transformer 20 (secondary coil) that receives the power of the carrier wave transmitted to the primary power supply circuit 18.

次に、２次側として、入力トランス１２（２次コイル）から出力される搬送波出力を増幅する搬送波増幅回路２１と、搬送波出力のうち、抵抗の不平衡分（上記（５）式の実数項分）を抽出し、更に、搬送波成分を除去する抵抗分位相検波回路２２と、搬送波出力のうち容量不平衡分（即ち、上記（５）式の虚数項成分）を抽出し、更に、搬送波成分を除去する容量分位相検波回路２３と、容量分の不平衡成分による位相のずれを補償量に変換する容量分打消し駆動回路２４と、前記補償量に比例する光量（輝度）を発光する光信号伝達手段１３の発光ダイオード１３ａと、容量分の不平衡成分による位相のずれの基準となる基準電圧（搬送波と位相が９０度ずれた電圧波形）を容量分位相検波回路２３に供給する移相回路２５と、を備える。
更に、２次側として、測定ブリッジ１１に入力する搬送波（例えば、５ｋＨｚ）を出力する搬送波発振回路としての発振回路２６と、発振回路２６の出力を１次側の測定ブリッジ１１に搬送波ブリッジ電圧として供給する結合トランス１９の１次コイルと、搬送波電力の励振電力として電力トランス２０（１次コイル）に供給するパワーアンプ２７と、２次側に含まれるすべての回路が使用する電力を供給する２次側電源２８と、を備える。 Next, as the secondary side, a carrier wave amplifier circuit 21 that amplifies the carrier wave output output from the input transformer 12 (secondary coil), and of the carrier wave output, the unbalanced portion of the resistance (the real term of the above equation (5)) And the resistance component phase detection circuit 22 for removing the carrier wave component, and the capacity unbalanced component (that is, the imaginary term component of the above equation (5)) from the carrier wave output, and the carrier wave component. Capacitance phase detection circuit 23 for removing noise, a capacitance canceling drive circuit 24 for converting a phase shift due to an unbalanced component of capacitance into a compensation amount, and light that emits a light amount (luminance) proportional to the compensation amount A phase shift circuit for supplying a reference voltage (a voltage waveform whose phase is shifted by 90 degrees from the carrier wave) to the capacitance phase detector 23 and the light emitting diode 13a of the signal transmission means 13 and the phase due to the unbalanced component corresponding to the capacitance. And a circuit 25.
Further, as the secondary side, an oscillation circuit 26 as a carrier wave oscillation circuit that outputs a carrier wave (for example, 5 kHz) input to the measurement bridge 11, and an output of the oscillation circuit 26 as a carrier wave bridge voltage to the measurement bridge 11 on the primary side. A primary coil of the coupling transformer 19 to be supplied, a power amplifier 27 to be supplied to the power transformer 20 (primary coil) as excitation power of the carrier power, and 2 to supply power used by all circuits included in the secondary side And a secondary power source 28.

以下、この第１の実施形態の搬送波型ひずみ測定装置が有する各回路構成要素について説明する。
先ず、１次側において、測定ブリッジ１１は、ひずみゲージをもってホイートストンブリッジ回路に構成されており、当該ひずみゲージは、被測定対象物に添着されて、そのひずみを検出する。
入力トランス１２（１次コイル）は、被測定対象物のひずみに比例する測定ブリッジからの出力（電圧値）を１次側（１次コイル）で受け、磁気結合により２次コイルに伝える。
光信号伝達手段１３（受光ダイオード１３ｂ側）は、容量不平衡分を打消し得る補償量に比例した発光ダイオード１３ａの発光量（輝度）を受けて、前記補償量に比例した出力（電圧値）を出力し、打消し回路１４に供給する。
一次側の打消し回路１４は、一種の変調回路であり、Ｂ．Ｖ波形供給回路１５が出力する搬送波波形の電圧値をリファレンス電圧として受けると共に、光信号伝達手段１３の受光ダイオード１３ｂが出力する補償量に比例した出力（電圧値と極性）とを入力して受け、前記補償量に比例した電圧値と上記極性に応じた位相（即ち９０°の遅れか、２７０°の遅れ）の搬送波で重畳した電圧値を入力トランス１２に帰還する。 Hereafter, each circuit component which the carrier wave type | mold distortion measuring apparatus of this 1st Embodiment has is demonstrated.
First, on the primary side, the measurement bridge 11 is configured as a Wheatstone bridge circuit with a strain gauge, and the strain gauge is attached to an object to be measured and detects the strain.
The input transformer 12 (primary coil) receives the output (voltage value) from the measurement bridge proportional to the strain of the object to be measured on the primary side (primary coil) and transmits it to the secondary coil by magnetic coupling.
The optical signal transmission means 13 (on the light receiving diode 13b side) receives the light emission amount (luminance) of the light emitting diode 13a proportional to the compensation amount capable of canceling the capacitance imbalance, and outputs (voltage value) proportional to the compensation amount. Is supplied to the cancellation circuit 14.
The cancellation circuit 14 on the primary side is a kind of modulation circuit. The voltage value of the carrier wave waveform output from the V waveform supply circuit 15 is received as a reference voltage, and the output (voltage value and polarity) proportional to the compensation amount output from the light receiving diode 13b of the optical signal transmission means 13 is input and received. The voltage value superimposed on the carrier wave having a voltage value proportional to the compensation amount and a phase corresponding to the polarity (that is, a delay of 90 ° or a delay of 270 °) is fed back to the input transformer 12.

ここで、Ｂ．Ｖ波形供給回路１５は、測定ブリッジ１１に入力する搬送波と同じ基準電圧波形とする電圧値を出力し、打消し回路１４に搬送波のリファレンスとして供給する。
較正値発生回路１６は、ひずみゲージに実際に負荷を掛けることなく、特定の１つまたは複数の較正値に対応する較正電圧を発生して入力トランス１２に印加する。
抵抗分調整回路１７は、ひずみゲージに負荷をかけない状態における測定ブリッジ１１の出力に含まれる抵抗分の初期不平衡成分を調整する（打消す）ことができる電圧値に対応する電圧を発生して搬送波に重畳して入力トランス１２に伝達する。
１次側電源回路１８は、２次側電源２８から電源の供給を受けて駆動するパワーアンプ回路２７によって励振される電力トランス２０（２次コイル）に接続されている。この１次側電源回路１８は、１次側の全ての回路要素が使用する電力を供給するためのものである。
結合トランス１９（２次コイル）は、２次側の発振回路２６で生成される搬送波（例えば、５ｋＨｚの発振周波数）をひずみの測定時に測定ブリッジ１１に入力する搬送波電源（いわゆるブリッジ電源）を、磁気結合で受けて測定ブリッジ１１に伝達する。 Here, B.I. The V waveform supply circuit 15 outputs a voltage value having the same reference voltage waveform as the carrier wave input to the measurement bridge 11 and supplies it to the cancellation circuit 14 as a carrier wave reference.
The calibration value generation circuit 16 generates a calibration voltage corresponding to one or more specific calibration values and applies the calibration voltage to the input transformer 12 without actually applying a load to the strain gauge.
The resistance adjustment circuit 17 generates a voltage corresponding to a voltage value that can adjust (cancel) the initial unbalance component of the resistance included in the output of the measurement bridge 11 when no load is applied to the strain gauge. And superimposed on the carrier wave and transmitted to the input transformer 12.
The primary power supply circuit 18 is connected to a power transformer 20 (secondary coil) that is excited by a power amplifier circuit 27 that is driven by power supplied from the secondary power supply 28. The primary power supply circuit 18 is for supplying power used by all circuit elements on the primary side.
The coupling transformer 19 (secondary coil) is a carrier power source (so-called bridge power source) that inputs a carrier wave (for example, an oscillation frequency of 5 kHz) generated by the secondary-side oscillation circuit 26 to the measurement bridge 11 when measuring distortion. Received by magnetic coupling and transmitted to the measurement bridge 11.

また、２次側において、搬送波増幅回路２１は、入力トランス１２（２次側コイル）から出力される測定ひずみを含む搬送波出力を増幅する増幅回路であり、この増幅結果の出力を、抵抗分位相検波回路２２と、容量分位相検波回路２３とに送出する。
抵抗分位相検波回路２２は、前記測定ひずみを含む搬送波出力から、測定プリッジ１１のホイートストンブリッジを構成する４辺の抵抗分の初期不平衡成分を抽出し、さらに搬送波成分を除去してひずみに対応した信号を出力する。但し、この抵抗分位相検波回路２２が検出した抵抗分の初期不平衡成分を打消して、これを補償する回路部分は、本発明の範囲外であるので、ここでの図示及び説明は省略する。
容量分位相検波回路２３は、前記測定ひずみを含む搬送波出力を搬送波増幅回路２１から受けると共に、発振回路２６の出力に対して９０°位相をずらせた出力を移相回路２５から受けて、容量不平衡成分を抽出し、搬送波を除去して容量分打消し駆動回路２４に送出する。
移相回路２５は、発振回路２６の出力に対し位相を９０°遅らせて、容量分位相検波回路２３に送出する。また、発振回路２６は、結合トランス１９を介して１次側の測定ブリッジ１１に印加する搬送波出力を生成する。この発振回路２６の出力は、上記移送回路２５と２次側の抵抗分位相検波回路２２とパワーアンプ回路２７にも送出される。 On the secondary side, the carrier amplifier circuit 21 is an amplifier circuit that amplifies the carrier wave output including the measurement distortion output from the input transformer 12 (secondary coil). The signal is sent to the detection circuit 22 and the phase detection circuit 23 for the capacity.
The resistance component phase detection circuit 22 extracts initial unbalanced components corresponding to the resistances of the four sides constituting the Wheatstone bridge of the measurement probe 11 from the carrier wave output including the measurement distortion, and further removes the carrier wave component to cope with the distortion. Output the signal. However, since the circuit portion for canceling the initial unbalance component of the resistance detected by the resistance phase detection circuit 22 and compensating for it is out of the scope of the present invention, the illustration and explanation here are omitted. .
The capacitance phase detection circuit 23 receives the carrier wave output including the measurement distortion from the carrier wave amplifier circuit 21, and also receives the output shifted by 90 ° from the output of the oscillation circuit 26 from the phase shift circuit 25. The balance component is extracted, the carrier wave is removed, and the amount is canceled by the capacity and sent to the drive circuit 24.
The phase shift circuit 25 delays the phase by 90 ° with respect to the output of the oscillation circuit 26 and sends it to the phase detection circuit 23 by a capacity. Further, the oscillation circuit 26 generates a carrier wave output to be applied to the measurement bridge 11 on the primary side via the coupling transformer 19. The output of the oscillation circuit 26 is also sent to the transfer circuit 25, the secondary resistance phase detection circuit 22 and the power amplifier circuit 27.

パワーアンプ２７は、発振回路２６が生成する搬送波（正弦波波形）の出力を増幅し、この増幅で得られた励振電圧を、電力トランス２０（１次コイル）に供給する。
電力トランス２０の２次コイルには、１次側電源回路１８が接続されている。この１次側電源回路１８からは、平滑化された直流電圧が生成され、１次側に含まれる回路要素へと供給される。
２次側電源２８は、２次側の全ての回路要素が使用する電力を供給する。
図２は、本発明の第２の実施形態に係る搬送波型ひずみ測定装置における要部の構成を示す回路図である。
図２においては、容量分打消し駆動回路２４、光信号伝達手段１３、容量分打消し回路１４およびこれらの接続関係を示している。
図２における容量分打消し駆動回路２４は、図１に示す回路と同じものであり、光信号伝達手段１３および打消し回路１４は、図１の実施の形態と同じ符号を用いているが実施の形態は異なっている。 The power amplifier 27 amplifies the output of the carrier wave (sine wave waveform) generated by the oscillation circuit 26 and supplies the excitation voltage obtained by this amplification to the power transformer 20 (primary coil).
A primary power supply circuit 18 is connected to the secondary coil of the power transformer 20. From the primary side power supply circuit 18, a smoothed DC voltage is generated and supplied to circuit elements included in the primary side.
The secondary power supply 28 supplies power used by all circuit elements on the secondary side.
FIG. 2 is a circuit diagram showing a configuration of a main part of a carrier-type distortion measuring apparatus according to the second embodiment of the present invention.
FIG. 2 shows the capacity canceling drive circuit 24, the optical signal transmission means 13, the capacity canceling circuit 14, and their connection.
The capacity cancellation drive circuit 24 in FIG. 2 is the same as the circuit shown in FIG. 1, and the optical signal transmission means 13 and cancellation circuit 14 use the same reference numerals as in the embodiment of FIG. The form of is different.

即ち、光信号伝達手段１３は、２次側電源２８に対し、第１の抵抗Ｒａと第１の発光ダイオードＤａと第２の発光ダイオードＤｂと第２の抵抗Ｒｂが直列に接続された直列回路と、
一次側電源回路１８に対し、第１の受光ダイオードＤｃと第３の抵抗Ｒｃが直列に接続された直列回路と、第２の受光ダイオードＤｄと第４の抵抗Ｒｄが直列に接続された直列回路が、互いに並列に接続された並列回路からなっている。
そして、第１の発光ダイオードＤａと第１の受光ダイオードＤｃとは、互いに接近して対峙して配設されており、また、第２の発光ダイオードＤｂと第２の受光ダイオードＤｄとは、同様に互いに接近して対峙して配設されている。
また、第１の抵抗Ｒａ、第２の抵抗Ｒｂ、第３の抵抗Ｒｃおよび第４の抵抗Ｒｄは、電流制限抵抗として機能を果たす。
光量電圧安定化回路１４ａは、受光ダイオードＤｃとＤｄから受光量情報を安定的に処理する回路であり、例えば、オペアンプを用いて構成することができ、光信号伝達手段１３から出力される２つの光量電圧がそれぞれ非反転入力端子（＋）と反転入力端子（−）とに供給されると、両入力電圧を比較し、非反転入力端子の電圧が反転入力端子の電圧よりも高ければ、正極性で且つ、入力電圧に対応した補償用電圧を出力し、逆の関係であれば、反対の極性の補償用電圧を出力する。 That is, the optical signal transmission means 13 is a series circuit in which the first resistor Ra, the first light emitting diode Da, the second light emitting diode Db, and the second resistor Rb are connected in series to the secondary power supply 28. When,
A series circuit in which a first light receiving diode Dc and a third resistor Rc are connected in series to a primary power supply circuit 18, and a series circuit in which a second light receiving diode Dd and a fourth resistor Rd are connected in series. Consists of parallel circuits connected in parallel to each other.
The first light emitting diode Da and the first light receiving diode Dc are arranged close to each other and face each other, and the second light emitting diode Db and the second light receiving diode Dd are the same. Are arranged in close proximity to each other.
Further, the first resistor Ra, the second resistor Rb, the third resistor Rc, and the fourth resistor Rd function as current limiting resistors.
The light amount voltage stabilizing circuit 14a is a circuit that stably processes the amount of light received from the light receiving diodes Dc and Dd. For example, the light amount voltage stabilizing circuit 14a can be configured by using an operational amplifier. When the light amount voltage is supplied to the non-inverting input terminal (+) and the inverting input terminal (−), respectively, both input voltages are compared. If the voltage of the non-inverting input terminal is higher than the voltage of the inverting input terminal, the positive electrode The compensation voltage corresponding to the input voltage is output, and if the relationship is reversed, the compensation voltage having the opposite polarity is output.

容量分打消し回路１４ｂは、光量電圧安定化回路１４ａから受ける入力が、例えば＋であれば、同位相の出力波形を出力し、−であれば、逆位相出力波形で且つ、入力電圧に応じた振幅の出力をＢＶ波形供給回路１５よりリファレンスとして受けた搬送波に重畳させて入力トランス１２の入力側に注入する。
上記の作用を、より具体的に説明すると、容量分打消し駆動回路２４からの出力値が＋であれば、第１の発光ダイオードＤａと第２の発光ダイオードＤｂとの接続電位が上昇し、第２の発光ダイオードＤｂの発光量（輝度）が第１の発光ダイオードＤａよりも大きくなり、これに伴い第２の受光ダイオードＤｄにより大きな光電流が流れることになる。
すると、第２の受光ダイオードＤｄと第４の抵抗Ｒｄとの接続点電位が大きくなり、第１の受光ダイオードＤｃと第３の抵抗Ｒｃとの接続点電位が小さくなり、その結果、光量電圧安定化回路１４ａにおける非反転入力端子（＋）よりも非反転入力端子（−）の入力電圧の方が高くなり、従って、光量電圧安定化回路１４ａからは、入力電圧に対応した大きさの（−）出力が現れる。
すると、この（−）出力を受ける容量分打ち消し回路１４ｂからは、リファレンス電圧とは、逆位相の補償量に対応した電圧を搬送波に重畳して、これを９０°移相コンデンサＣ５を介して、入力トランス１２の１次側コイルに注入する。 If the input received from the light amount voltage stabilization circuit 14a is, for example, +, the capacitance cancellation circuit 14b outputs an output waveform having the same phase, and if it is −, the capacitance cancellation circuit 14b has an anti-phase output waveform and corresponds to the input voltage. The output having the amplitude is superimposed on the carrier wave received as a reference from the BV waveform supply circuit 15 and injected to the input side of the input transformer 12.
The above operation will be described more specifically. If the output value from the capacitance canceling drive circuit 24 is +, the connection potential between the first light emitting diode Da and the second light emitting diode Db increases, The light emission amount (luminance) of the second light emitting diode Db becomes larger than that of the first light emitting diode Da, and accordingly, a large photocurrent flows through the second light receiving diode Dd.
Then, the connection point potential between the second light receiving diode Dd and the fourth resistor Rd is increased, and the connection point potential between the first light receiving diode Dc and the third resistor Rc is decreased. The input voltage at the non-inverting input terminal (−) is higher than that at the non-inverting input terminal (+) in the inverting circuit 14a. Therefore, the light amount voltage stabilizing circuit 14a has a magnitude corresponding to the input voltage (− ) Output appears.
Then, from the capacitance canceling circuit 14b receiving this (−) output, a voltage corresponding to the compensation amount of the antiphase with the reference voltage is superimposed on the carrier wave, and this is passed through the 90 ° phase shift capacitor C5. Injection into the primary coil of the input transformer 12.

また、容量分打消し駆動回路２４からの出力値が−（マイナス）であれば、上述したところと反対の作用となり、容量分打消し回路１４ｂからは、リファレンスと同相の補償量に対応した電圧を搬送波に重畳して、これを９０°移相コンデンサＣ５を介して入力トランス１２の１次側コイルに注入することになる。
尚、光信号伝達手段１３については、図１に示すように、１つの発光ダイオード１３ａと１つの受光ダイオード１３ｂによっても、容量不平衡分の情報を電気的に絶縁した状態が光信号に変換して信号を伝達することが可能ではあるが、光信号を安定して伝達し難いことが判明したため、図２に示すように、光信号伝達手段１３として、第１の抵抗Ｒａと第１の発光ダイオードＤａと第２の発光ダイオードＤｂと第２の抵抗Ｒｂとよりなる直列回路と、
第１の受光ダイオードＤｃと第３の抵抗Ｒｃとからなる直列回路と、第２の受光ダイオードＤｄと第４の抵抗Ｒｄとよりなる直列回路とを互いに並列に接続すると共に、前記容量分打消し回路１４ｂは、前記光信号伝達手段１３の前記第１の受光ダイオードＤｃと前記第３の抵抗Ｒｃとの接続点電位と、前記第２の受光ダイオードＤｄと前記第４の抵抗Ｒｄとの接続点電位を比較して、補償量の電位と極性を判定し、出力波形の振幅と位相を決定して出力するように構成することによって、極めて安定的に補償用の電位に変換することができる。 If the output value from the capacitance canceling drive circuit 24 is-(minus), the operation is opposite to that described above, and the voltage canceling circuit 14b provides a voltage corresponding to the compensation amount in phase with the reference. Is superimposed on the carrier wave and injected into the primary coil of the input transformer 12 through the 90 ° phase shift capacitor C5.
As for the optical signal transmission means 13, as shown in FIG. 1, the state in which the information on the capacitance imbalance is electrically insulated is also converted into an optical signal by one light emitting diode 13a and one light receiving diode 13b. However, as shown in FIG. 2, as the optical signal transmission means 13, the first resistor Ra and the first light emission are provided. A series circuit including a diode Da, a second light emitting diode Db, and a second resistor Rb;
A series circuit composed of the first light receiving diode Dc and the third resistor Rc and a series circuit composed of the second light receiving diode Dd and the fourth resistor Rd are connected in parallel to each other, and cancel the capacitance. The circuit 14b includes a connection point potential between the first light receiving diode Dc and the third resistor Rc of the optical signal transmission unit 13, and a connection point between the second light receiving diode Dd and the fourth resistor Rd. By comparing the potentials, determining the potential and polarity of the compensation amount, and determining and outputting the amplitude and phase of the output waveform, the potential can be converted to the compensation potential extremely stably.

図３は、本発明の第３の実施の形態に係る搬送波型ひずみ測定装置における打消し回路からの出力電圧（補償量）を、帰還するための回路構成を示す回路図である。
この第３の実施形態によれば、例えば、図１の打消し回路１４からの打消し電圧のうち、容量不平衡分を打消す搬送波（正弦波）信号が同相か逆相かに応じて入力トランス１２への入力形態を異ならせている。
即ち、同位相の場合、容量分打消し回路１４の出力を受けて、これを増幅する打消し電圧増幅回路３０は、９０°移相コンデンサＣ５を介して入力トランス１２の１次側コイルの一端に打消し電圧を搬送波に重畳させて供給する。
さらに容量分打ち消し回路１４の出力を受けてこれを増幅する打消し電圧増幅回路３０からの出力を、打消し電圧位相反転回路（例えばインバータ）３１を介して反転されて、入力トランス１２の１次側コイルの他端に、逆位相の搬送波打消し電圧を重畳させて供給する。
このように構成することにより、打消し電圧の振幅が図１に示す構成のものに対して１／２ですみ、これにより直線性の良好なところが使用することができ、打消し波形が歪むことなく、きれいな波形で注入されるため、より高精度に容量不平衡分を常に打消し得る搬送波型ひずみ測定装置を提供することができる。 FIG. 3 is a circuit diagram showing a circuit configuration for feeding back the output voltage (compensation amount) from the cancellation circuit in the carrier wave distortion measuring apparatus according to the third embodiment of the present invention.
According to the third embodiment, for example, of the cancellation voltage from the cancellation circuit 14 of FIG. 1, the carrier wave (sine wave) signal that cancels the capacitive imbalance is input according to whether it is in phase or in phase. The input form to the transformer 12 is different.
That is, in the case of the same phase, the cancellation voltage amplification circuit 30 that receives and amplifies the output of the cancellation circuit 14 for the capacitance is connected to one end of the primary side coil of the input transformer 12 via the 90 ° phase shift capacitor C5. Is supplied with a canceling voltage superimposed on the carrier wave.
Further, the output from the cancellation voltage amplification circuit 30 that receives and amplifies the output of the capacitance cancellation circuit 14 is inverted through a cancellation voltage phase inversion circuit (for example, an inverter) 31, and the primary of the input transformer 12 is inverted. An opposite-phase carrier cancellation voltage is superimposed on the other end of the side coil and supplied.
With this configuration, the amplitude of the canceling voltage is ½ that of the configuration shown in FIG. 1, so that a portion with good linearity can be used, and the canceling waveform is distorted. Therefore, a carrier wave type distortion measuring apparatus that can always cancel out the capacity imbalance with higher accuracy can be provided.

また、第１〜第３の実施形態のいずれによっても、搬送波を使用することにより、極めて変化の早い動的現象を測定することが可能であり、容量不平衡分を瞬時に且つ高精度に打ち消すことが可能であり、また、測定ブリッジや打ち消し回路、２次側電源回路が含まれる１次側回路部分と、搬送波増幅回路、容量分位相検波回路、容量分打ち消し駆動回路、発振回路および２次側電源が含まれる回路部分とを直接接続することなく、トランスのような電磁結合手段と発光ダイオードと受光ダイオードのような光信号伝達手段を介して接続する構成としたので、ノイズの混入、特に２次側回路からのノイズが混入することがなく、高精度な動的ひずみの測定が可能となる。   Also, according to any of the first to third embodiments, it is possible to measure a dynamic phenomenon that changes very quickly by using a carrier wave, and cancels the capacity imbalance instantly and with high accuracy. In addition, a primary side circuit portion including a measurement bridge, a cancellation circuit, and a secondary power supply circuit, a carrier amplifier circuit, a capacitive phase detection circuit, a capacitive cancellation drive circuit, an oscillation circuit, and a secondary circuit Without connecting directly to the circuit part including the side power supply, it is configured to be connected via an electromagnetic coupling means such as a transformer and an optical signal transmission means such as a light emitting diode and a light receiving diode. Noise from the secondary side circuit is not mixed, and dynamic strain can be measured with high accuracy.

１１ 測定ブリッジ
１２ 入力トランス
１３ 光信号伝達手段
１３ａ 発光ダイオード
１３ｂ 受光ダイオード
１４ 打消し回路
１４ａ 光量電圧安定化回路
１４ｂ 容量分打消し回路
１５ Ｂ．Ｖ波形供給回路
１６ 較正値発生回路
１７ 抵抗分調整回路
１８ １次側電源回路
１９ 結合トランス
２０ 電力トランス
２１ 搬送波増幅回路
２２ 抵抗分位相検波回路
２３ 容量分位相検波回路
２４ 容量分打消し駆動回路
２５ 移相回路
２６ 発振回路
２７ パワーアンプ回路
２８ ２次側電源
３０ 打消し電圧増幅回路
３１ 打消し電圧位相反転回路
Ｃ５、Ｃ６、９０° 移相コンデンサ DESCRIPTION OF SYMBOLS 11 Measurement bridge 12 Input transformer 13 Optical signal transmission means 13a Light emitting diode 13b Light receiving diode 14 Cancellation circuit 14a Light quantity voltage stabilization circuit 14b Capacity cancellation circuit 15B. V waveform supply circuit 16 Calibration value generation circuit 17 Resistance adjustment circuit 18 Primary power supply circuit 19 Coupling transformer 20 Power transformer 21 Carrier amplifier circuit 22 Resistance phase detection circuit 23 Capacitance phase detection circuit 24 Capacitance cancellation drive circuit 25 Phase shift circuit 26 Oscillation circuit 27 Power amplifier circuit 28 Secondary side power supply 30 Cancellation voltage amplification circuit 31 Cancellation voltage phase inversion circuit C5, C6, 90 ° Phase shift capacitor

Claims (5)

搬送波型ひずみ測定装置において、
ひずみゲージを含む測定ブリッジと、
前記測定ブリッジに結合トランスを介して印加する搬送波を発生する搬送波発振回路と、
前記測定ブリッジに印加される搬送波に重畳された測定信号を入力トランスを介して受け増幅する搬送波増幅回路と、
前記搬送波増幅回路の出力を受けて前記測定ブリッジの容量変化分に対応する不平衡成分を抽出し、前記不平衡成分に対応した補償量の信号を出力する容量分位相検波回路と、
少なくとも１つの発光ダイオードとこれと対峙するように配置された受光ダイオードからなる光信号伝達手段と、
前記補償量の信号に応じて前記発光ダイオードの発光輝度を制御する容量分打消し駆動回路と、
前記発光ダイオードの発光を受けて、電気信号に変換する前記受光ダイオードに流れる電流に応じて前記補償量に対応した極性と振幅を持つ補償用電位に変換し、前記極性に応じて出力波形の位相を変えて前記搬送波に前記補償用電位を重畳して前記入力トランスの１次側に供給し、前記測定ブリッジに発生する容量成分による不平衡成分を自動的に打消す容量分打消し回路と、
２次側の各回路に電力を供給する２次側電源と、
前記２次側電源から電力トランスを介して電力を受け、１次側の各回路に電力を供給する１次側電源回路と、
を具備し、
前記搬送波増幅回路、前記容量分位相検波回路、前記容量分打消し駆動回路、前記発光ダイオード、前記搬送波発振回路および前記２次側電源に対し、
前記測定ブリッジ、前記容量分打消し回路、前記受光ダイオードおよび前記１次側電源回路は、
前記入力トランス、前記光信号伝達手段、前記結合トランスおよび前記電力トランスからなる電磁的手段および前記光信号伝達手段により接続され、電気的には絶縁された状態で接続されていることを特徴とする搬送波型ひずみ測定器。 In a carrier-type strain measuring device,
A measurement bridge including a strain gauge;
A carrier wave oscillation circuit for generating a carrier wave to be applied to the measurement bridge via a coupling transformer;
A carrier amplifier circuit that receives and amplifies a measurement signal superimposed on a carrier wave applied to the measurement bridge via an input transformer;
Receiving the output of the carrier wave amplifier circuit, extracting an unbalanced component corresponding to the capacitance change of the measurement bridge, and outputting a compensation phase signal corresponding to the unbalanced component;
An optical signal transmission means comprising at least one light-emitting diode and a light-receiving diode disposed to face the light-emitting diode;
A capacitance canceling drive circuit for controlling the light emission luminance of the light emitting diode according to the compensation amount signal;
The light emission from the light emitting diode is converted into an electric signal, converted into an electric signal, converted into a compensation potential having a polarity and amplitude corresponding to the compensation amount according to the current flowing through the light receiving diode, and the phase of the output waveform according to the polarity And the compensation potential is superimposed on the carrier wave and supplied to the primary side of the input transformer, and a capacitance canceling circuit for automatically canceling the unbalanced component due to the capacitance component generated in the measurement bridge;
A secondary power supply for supplying power to each circuit on the secondary side;
A primary power supply circuit that receives power from the secondary power supply via a power transformer and supplies power to each circuit on the primary side;
Comprising
For the carrier wave amplification circuit, the capacitance phase detection circuit, the capacitance cancellation drive circuit, the light emitting diode, the carrier wave oscillation circuit, and the secondary power supply,
The measurement bridge, the capacitance canceling circuit, the light receiving diode, and the primary power circuit are:
The input transformer, the optical signal transmission means, the electromagnetic means comprising the coupling transformer and the power transformer, and the optical signal transmission means are connected and are electrically insulated and connected. Carrier type strain measuring instrument. 前記光信号伝達手段は、第１の抵抗と第１の発光ダイオードと第２の発光ダイオードと第２の抵抗とよりなる直列回路と、
第１の受光ダイオードと第３の抵抗とからなる直列回路と、第２の受光ダイオードと第４の抵抗とよりなる直列回路とが互いに並列に接続されてなることを特徴とする請求項１に記載の搬送波型ひずみ測定装置。 The optical signal transmission means includes a first circuit including a first resistor, a first light emitting diode, a second light emitting diode, and a second resistor.
2. A series circuit comprising a first light receiving diode and a third resistor and a series circuit comprising a second light receiving diode and a fourth resistor are connected in parallel to each other. The carrier-type distortion measuring apparatus as described. 前記容量分打消し回路は、前記光信号伝達手段の前記第１の受光ダイオードと前記第３の抵抗との接続点電位と、前記第２の受光ダイオードと前記第４の抵抗との接続点電位とを比較して前記補償量の電位と極性を判定し、出力波形の振幅と位相を決定して出力するように構成されていることを特徴とする請求項２に記載の搬送波型ひずみ測定装置。   The capacitance canceling circuit includes a connection point potential between the first light receiving diode and the third resistor of the optical signal transmission means, and a connection point potential between the second light receiving diode and the fourth resistor. The carrier wave type distortion measuring apparatus according to claim 2, wherein the compensation type potential is determined by comparing the signal and the polarity of the compensation amount, and the amplitude and phase of the output waveform are determined and output. . 特定の１つまたは複数の較正値に対応する較正電圧を発生する較正値発生回路の出力を、前記搬送波に重畳して前記入力トランスの１次側に選択的に供給し得るように構成されていることを特徴とする請求項１に記載の搬送波型ひずみ測定装置。   An output of a calibration value generating circuit that generates a calibration voltage corresponding to one or more specific calibration values is configured to be selectively supplied to the primary side of the input transformer superimposed on the carrier wave. The carrier-type distortion measuring apparatus according to claim 1, wherein: 前記測定ブリッジの抵抗値の初期不平衡分を打消す電位を発生する抵抗分調整回路の出力を、前記搬送波に重畳して前記入力トランスの１次側に常時供給するように構成されていることを特徴とする請求項１に記載の搬送波型ひずみ測定装置。   The output of a resistance adjustment circuit that generates a potential that cancels the initial unbalance of the resistance value of the measurement bridge is configured to be constantly supplied to the primary side of the input transformer, superimposed on the carrier wave. The carrier-type distortion measuring apparatus according to claim 1.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102338485A (en) * 2011-06-10 2012-02-01 常州大学 Safety protection method and device of driving unit of groove type solar heat generating condenser
JP2012154701A (en) * 2011-01-24 2012-08-16 Kyowa Electron Instr Co Ltd Carrier wave type dynamic strain measuring instrument

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JPS58113801A (en) * 1981-12-28 1983-07-06 Kyowa Dengiyou:Kk Method and device for measuring strain
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JPH0216441B2 (en) * 1981-11-02 1990-04-17 Kyowa Electronic Instruments
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JP2012154701A (en) * 2011-01-24 2012-08-16 Kyowa Electron Instr Co Ltd Carrier wave type dynamic strain measuring instrument
CN102338485A (en) * 2011-06-10 2012-02-01 常州大学 Safety protection method and device of driving unit of groove type solar heat generating condenser

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