CN205102964U - Portable soft organizational interface force measuring system of multichannel - Google Patents
Portable soft organizational interface force measuring system of multichannel Download PDFInfo
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- CN205102964U CN205102964U CN201520939496.9U CN201520939496U CN205102964U CN 205102964 U CN205102964 U CN 205102964U CN 201520939496 U CN201520939496 U CN 201520939496U CN 205102964 U CN205102964 U CN 205102964U
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- soft tissue
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- tissue interface
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Abstract
The utility model discloses a portable soft organizational interface force measuring system of multichannel, including thin -film sensor, wherein: thin -film sensor has connected gradually digital conversion unit, signal conditioning unit, data acquisition unit, the signal conditioning unit is including the power supply circuit, bridge circuit, amplifier circuit, the filter circuit that connect gradually. This system has reduced the interference of power to voltage signal, and its voltage signal transmission is stable, it is accurate to calculate, the precision is high, the real -time good, and simple structure, convenient operation.
Description
Technical field
The utility model relates to a kind of dynamometric system, particularly relates to a kind of multichannel film dynamometric system.
Background technology
Soft tissue interface dynamometric system is based on its special stressing conditions, and after soft tissue is subject to certain ambient pressure, its distortion is nonlinear often, and this just brings very large difficulty to the force and deformation situation that we study each point of soft tissue.In present many researchs, researchist generally for conveniently, calculates simple, often soft tissue interface is reduced to rigid body, linear deformation, so not only can causes very large error, cause the inaccuracy of experimental data, be also unfavorable for our further investigation to soft tissue interface simultaneously.
The soft tissue interface dynamometric system of current use has following defect:
(1), the interference of power supply to voltage signal of dynamometric system is large;
(2), the voltage signal of dynamometric system is unstable, is unfavorable for reducing impedance;
(3), the precision of the voltage signal of dynamometric system is not high, and data are inaccurate, do not carry out the conditioning of signal.
Utility model content
The purpose of this utility model is to provide a kind of multi-channel portable soft tissue interface dynamometric system, the system reduces the interference of power supply to voltage signal, the transmission of its voltage signal is stable, calculating is accurate, precision is high, real-time good, and structure is simple, easy to operate.
The utility model realizes its goal of the invention, and the technical scheme adopted is:
A kind of multi-channel portable soft tissue interface dynamometric system, comprises thin film sensor, wherein: described thin film sensor is connected with digital conversion unit, signal condition unit, data acquisition unit in turn; Described signal condition unit comprises the power circuit, bridge diagram, amplifying circuit, the filtering circuit that connect successively.
Further, above-mentioned data acquisition unit comprises data collecting plate card, and described data collecting plate card comprises the sample buffer, D/A converter, programmable amplifier, the multiplexer that connect successively; Described sample buffer is also connected with D/A converter, USB controller, signal o controller in turn, and described multiplexer is connected with signal condition unit; Described sample buffer is also connected with USB controller, and described converter is also connected with A/D converter, programmable amplifier, multiplexer respectively; Described USB controller is also connected with usb data bus.
Further, above-mentioned power circuit comprises accumulator, connected boost converter.
Further, above-mentioned bridge diagram is half-bridge wheatstone bridge circuit, and described half-bridge wheatstone bridge circuit comprises relay, and described relay is connected with described thin film sensor.
Further, above-mentioned amplifying circuit comprises instrument amplification chip, and the input end of described instrument amplification chip is connected with the output terminal of half-bridge wheatstone bridge circuit.
Further, above-mentioned filtering circuit is the voltage-controlled type low-pass filter circuit of second order, and the voltage-controlled type low-pass filter circuit of described second order comprises Order RC wave filter, the bipolar amplifier of connected non-chopper-zero-stabilized; The voltage-controlled input end of type low-pass filter circuit of described second order is connected with the output terminal of amplifying circuit.
Compared with prior art, the beneficial effects of the utility model are:
(1), the DC voltage of accumulator is converted to galvanic current pressure by the utility model, makes its output voltage be stable voltage, which reduces the interference to voltage signal.
(2), the utility model input impedance is higher, common mode inhibition is higher, noise is low, linear error is low, offset drift is low, gain can be arranged flexibly, uses also more convenient.
(3), voltage signal of the present utility model is highly stable, is also beneficial to very much reduction impedance.
(4), voltage signal of the present utility model after conditioning, its precision is high, and data are accurate, are more conducive to the accuracy of experimental data, is also more conducive to the deep study and analysis to soft tissue interface simultaneously.
Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.
Accompanying drawing explanation
Fig. 1 is the power circuit diagram of signal condition unit in the utility model embodiment one.
Fig. 2 is the half-bridge wheatstone bridge circuit diagram of signal condition unit in the utility model embodiment one.
Fig. 3 is the magnifier figure of signal condition unit in the utility model embodiment one.
Fig. 4 is the second order voltage-controlled type low-pass filter circuit figure of signal condition unit in the utility model embodiment one.
Fig. 5 is the structured flowchart of the utility model embodiment one data collecting plate card.
Embodiment
Embodiment one
A kind of embodiment of the present utility model is: a kind of multi-channel portable soft tissue interface dynamometric system, and comprise thin film sensor, wherein said thin film sensor is connected with digital conversion unit, signal condition unit, data acquisition unit in turn; Described signal condition unit comprises the power circuit, bridge diagram, amplifying circuit, the filtering circuit that connect successively.
Fig. 5 illustrates, the data acquisition unit of this example comprises data collecting plate card, the data collecting plate card USB-4704 of the Shi Yanhua company adopted realizes, and data collecting plate card USB-4704 comprises the 512BytesFIFO sample buffer connected successively, 14 D/A converters, PGIA programmable amplifier, MUX multiplexers; Described 512BytesFIFO sample buffer is also connected with 14 A/D converters, CPLDUSB controller, signal o controller in turn, and described MUX multiplexer is connected with signal condition unit; Described 512BytesFIFO sample buffer also CPLDUSB controller connects, and described 14 D/A converters are also connected with 14 A/D converters, PGIA programmable amplifier, MUX multiplexer respectively; Described CPLDUSB controller is also connected with usb data bus, and usb data bus is connected with host computer (as computer etc.) again.
Data acquisition unit gathers electricity or non-electric charge quantity signalling automatically from thin film sensor, is processed by signal condition unit, transfers in host computer; The follow-up work that data acquisition unit is dynamometric system provides Data Source, ensure that data can process.
Fig. 1 illustrates, the power circuit of this example comprises accumulator, connected boost converter.The power supply of this example employs boost converter (LM27313), the 5V DC voltage of accumulator is converted to stable 12V DC voltage, devises some electric capacity and diode element, has carried out simple process to signal.Chip LM27313 is a kind of boost converter and voltage stabilizer of current-mode, and its frequency of operation is fixed as 1.6 megahertzes, and this chip adopts SOP-23 encapsulation, the minimum loss 800mA that switching current reduces, and small inductor wherein and capacitor cause power density high; In chip, the internal switch of 30V can make the voltage needed for solution be 5-28V; Chip includes a logic switch pin, can reduce the quiescent current of chip, extends the life-span of chip; Chip employing restrictive cycle electric current and heat shutoff function can realize the protection to self; The internal compensation circuit of chip also simplify design, decreases the quantity of components and parts.For the feature of this boost converter chips, the corresponding circuit of this modular design, configure the resistance, the capacity cell that adapt, its output voltage made is stable direct current 12V, output voltage as shown in Figure 1: Ut=-V1 (R1/Rs).
Fig. 2 illustrates, the bridge diagram of this example is half-bridge wheatstone bridge circuit, and described half-bridge wheatstone bridge circuit comprises relay, and described relay J 1 is connected with described thin film sensor.
When tested holding force signal is converted into self-resistance change by diaphragm pressure sensor, electric bridge can be converted into this resistance subtle change the change of bridge output voltage.Resistance variations feature when this problem loads according to sensor sensing district, devise half-bridge wheatstone bridge circuit, elementary amplification process can be carried out to the voltage that sensor exports, circuit diagram as shown in Figure 2, its main opsonic action the change of resistance is converted into voltage to export, and facilitates follow-up signal transacting.
Fig. 3 illustrates, the amplifying circuit of this example comprises instrument amplification chip, and the input end VIN1+ of described instrument amplification chip is connected with the output terminal VIN1+ of half-bridge wheatstone bridge circuit.
Diaphragm pressure sensor is connected in half-bridge wheatstone bridge circuit, and the change of diaphragm pressure sensor resistance is converted into voltage and exports by electric bridge, and the output voltage of bridge diagram is the input signal of amplifying circuit.Magnifier comes from operational amplifier, but is better than operational amplifier, is a kind of more accurate differential amplifier circuit; Magnifier has good DC common-mode rejection ratio, and alternating CMRR is poor.By key components being integrated in the inside of amplifier, unique instrument amplifier structure makes it have many excellent characteristics, such as: input impedance is higher, common mode inhibition is higher, noise is low, linear error is low, offset drift is low, gain can be arranged flexibly, it is more convenient etc. to use.Magnifier amplifies at the signal of sensor, data acquisition, Medical Instruments, high speed signal regulate and the stereo set Application comparison of top grade is extensive.Operational amplifier is the closed loop gain adjusting amplifier by being connected non-essential resistance between inverting input with output terminal, different from operational amplifier, it is by using the internal feedback resistor network of isolating with input end that magnifier adjusts its closed loop gain.When magnifier input end applies two differential input signals, user can use inner pin to arrange gain or to use and the input signal non-essential resistance of isolating arranges gain, also can use internal feedback resistor network.
This example adopts integrated computation amplification chip (INA128) to design magnifier.Integrated computation amplification chip (INA128) is a kind of general instrument amplification chip, has low-power consumption, high-precision advantage.INA128 chip volume small and exquisite employing three amplifier (3-opamp) designs, and makes it be applicable to a lot of aspect.Even if under high gain settings conditions (during G=100,200kHz), the input circuit of feedback current also can provide wider bandwidth.INA128 chip can realize arbitrary gain selection of 1-1000 by the resistance arranging single non-essential resistance.Adopt laser to carry out finely tuning the INA128 chip revised and have lot of advantages, such as bias voltage very low (50mV), common mode inhibition higher (when G=100,120dB), temperature drift are 0.5uV/ DEG C.INA128 chip is low to moderate ± 2.25V at supply voltage, and the electric current of its static state only has 700uA, and the inside of chip has input protection can bear ± and 40V voltage is without damage.The packing forms of INA128 chip is generally SO-8 surface substrate or 8 pin plastic DIP, and the operating temperature range of regulation is-40 DEG C to+85 DEG C.The circuit diagram of magnifier as shown in Figure 3.
Fig. 4 illustrates, the filtering circuit of this example is the voltage-controlled type low-pass filter circuit of second order, and the voltage-controlled type low-pass filter circuit of described second order comprises Order RC wave filter, the bipolar amplifier of connected non-chopper-zero-stabilized; The voltage-controlled input end of type low-pass filter circuit of described second order is connected with the output terminal of amplifying circuit.
The usual function of filtering circuit is smoothly by the signal of a certain component frequency, and suppresses the signal of other a part of frequency, thus effectively processes input signal.The voltage-controlled type low-pass filter circuit of second order is made up of Order RC filtering circuit and in-phase proportion amplifier, is a kind of active filter circuit, is suitable as the cascade of polystage amplifier.The signal of higher level's magnifier transmission is low-frequency voltage signal, and for making output voltage at high band with speed decline faster, the filtering circuit of this example adopts the voltage-controlled low-pass filter circuit of typical second order, and integrated computation amplification chip OP07CP is selected in design.
Integrated computation amplification chip OP07CP is a kind of bipolar amplifier of non-chopper-zero-stabilized, there is the advantages such as low noise, input offset voltage little (being 25uA to the maximum), open-loop gain high (300V/mV), input bias current low (± 2nA), this chip does not need to add extra zeroing measure simultaneously, the low imbalance that OP07 chip has, the characteristic of high open-loop gain its high-gain at measuring equipment is arranged and sensor feeble signal amplification in particularly suitable.This dynamometric system utilizes the good characteristic of this chip, devises the voltage-controlled type low-pass filter circuit of second order be relatively suitable for, as shown in Figure 4.
Principle of work and the process of the present embodiment are:
When the thin membrane regions of thin film sensor is under pressure, tested holding force signal is converted into the change of self-resistance value by thin film sensor; Diaphragm pressure sensor is connected in half-bridge single armed circuit, and the change of thin film sensor resistance is converted into voltage and exports by half-bridge wheatstone bridge, and the output voltage of half-bridge wheatstone bridge circuit is the input signal of amplifying circuit; Again by the amplification in modulate circuit, filtering, fall low-impedance effect and change into voltage signal, then data acquisition unit is utilized, computing machine is imported accurately in real time after voltage signal acquisition process, again by the calculating of computing machine, selection and feedback, real-time reflects the stressing conditions curve at soft tissue interface on computers, data required for Real Time Observation, acquisition process, for experiment provides data foundation more accurately.
Thin film sensor of the present utility model is a kind of lightweight, and volume is little, and sensing precision is high, extra-thin pressure transducer, be specially for soft tissue interface piezometry designed by.Data collecting plate card of the present utility model is the computer extender card realizing data acquisition function, can also pass through PXI, PCI, PCIExpress, live wire (1394), PCMCIA, ISA, CompactFlash, 485,232, Ethernet, the bus such as various wireless networks access personal computer.
Claims (6)
1. a multi-channel portable soft tissue interface dynamometric system, comprises thin film sensor, it is characterized in that: described thin film sensor is connected with digital conversion unit, signal condition unit, data acquisition unit in turn; Described signal condition unit comprises the power circuit, bridge diagram, amplifying circuit, the filtering circuit that connect successively.
2. a kind of multi-channel portable soft tissue interface according to claim 1 dynamometric system, it is characterized in that: described data acquisition unit comprises data collecting plate card, described data collecting plate card comprises the sample buffer, A/D converter, programmable amplifier, the multiplexer that connect successively; Described sample buffer is also connected with D/A converter, USB controller, signal o controller in turn, and described multiplexer is connected with signal condition unit; Described sample buffer is also connected with USB controller, and described A/D converter is also connected with D/A converter, programmable amplifier, multiplexer respectively; Described USB controller is also connected with usb data bus.
3. a kind of multi-channel portable soft tissue interface according to claim 1 dynamometric system, is characterized in that: described power circuit comprises accumulator, connected boost converter.
4. a kind of multi-channel portable soft tissue interface according to claim 3 dynamometric system, it is characterized in that: described bridge diagram is half-bridge wheatstone bridge circuit, described half-bridge wheatstone bridge circuit comprises relay, and described relay is connected with described thin film sensor.
5. a kind of multi-channel portable soft tissue interface according to claim 4 dynamometric system, it is characterized in that: described amplifying circuit comprises instrument amplification chip, the input end of described instrument amplification chip is connected with the output terminal of half-bridge wheatstone bridge circuit.
6. a kind of multi-channel portable soft tissue interface according to claim 5 dynamometric system, it is characterized in that: described filtering circuit is the voltage-controlled type low-pass filter circuit of second order, the voltage-controlled type low-pass filter circuit of described second order comprises Order RC wave filter, the bipolar amplifier of connected non-chopper-zero-stabilized; The voltage-controlled input end of type low-pass filter circuit of described second order is connected with the output terminal of amplifying circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520939496.9U CN205102964U (en) | 2015-11-20 | 2015-11-20 | Portable soft organizational interface force measuring system of multichannel |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201520939496.9U CN205102964U (en) | 2015-11-20 | 2015-11-20 | Portable soft organizational interface force measuring system of multichannel |
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| CN205102964U true CN205102964U (en) | 2016-03-23 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105676751A (en) * | 2016-03-31 | 2016-06-15 | 西南交通大学 | Multi-channel universal data acquisition device |
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- 2015-11-20 CN CN201520939496.9U patent/CN205102964U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105676751A (en) * | 2016-03-31 | 2016-06-15 | 西南交通大学 | Multi-channel universal data acquisition device |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20160323 Termination date: 20161120 |