CN1073918C - Control system for controlling motor-driven injection molding machinewith improved response - Google Patents
Control system for controlling motor-driven injection molding machinewith improved response Download PDFInfo
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- CN1073918C CN1073918C CN97112178A CN97112178A CN1073918C CN 1073918 C CN1073918 C CN 1073918C CN 97112178 A CN97112178 A CN 97112178A CN 97112178 A CN97112178 A CN 97112178A CN 1073918 C CN1073918 C CN 1073918C
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- servomotor
- amplifier
- speed
- torque instruction
- instruction value
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Abstract
The present invention relates to a control system for controlling a motor-driven injection molding machine which comprises an injection component and a speed feedback control loop, wherein the injection component is driven by a servo motor; the speed feedback control loop is used for controlling the servo motor. An instruction signal generated by a magnifier represents the torque instruction value of the servo motor; the torque instruction value is corresponding to the difference of a speed value and a speed instruction value tested by a rotary speed sensor. The present invention also comprises a pressure sensor, a correcting amplifier and an adder, wherein the pressure sensor is used for testing resin pressure in a mould and generating a pressure signal; the correcting amplifier is used for testing the pressure signal and generating a signal as the correction value of the torque instruction value; the adder is used for adding the torque instruction value and the correction value and transmitting to a motor driver.
Description
The present invention relates to a kind of control system of controlling motor-driven injection molding machine, this injector has an injection member by driven by servomotor.
Motor-driven injection molding machine has an injection member, and it is by driven by servomotor.Injection member comprises a ball-screw, nut and a block pressur plate.Ball-screw rotates along with the rotation of servomotor.Nut then moves forward and backward along forward or backwards rotation by ball-screw.Pressing plate and nut are collaborative to move forward and backward.The screw rod that is arranged in the injection cylinder moves forward and backward accordingly according to seesawing of pressing plate.
Do below to describe more specifically, servomotor is controlled by a speed feedback control loop.The speed feedback control loop comprises an amplifier, a motor driver, a rotation speed sensor and a subtracter.Amplifier receives a speed value and it is amplified generation one output servomotor torque instruction value.Motor driver drives servomotor according to the output of amplifier.Rotation speed sensor with the rotary speed that detects servomotor as the velocity amplitude of measuring.Subtracter is arranged on the amplifier input terminal side and deducts the velocity amplitude of measuring generation one result who subtracts each other who is obtained by rotation speed sensor from speed value transports to velocity-variation amplifier.
The output that is added on the amplifier of motor driver is to be used to follow speed value torque instruction value afterwards.Under these circumstances, quicken or the torque of slowing down be for quicken or the deceleration servomotor required.Torque instruction value is produced by amplifier, this just need to amplifier speed value is provided and the velocity amplitude measured between poor, i.e. velocity deviation.This means and velocity deviation when servomotor needs a torque, occurs.Velocity deviation can be as the index of speed feedback control loop response for this reason.
For better response littler velocity deviation is arranged preferably.In principle, if amplifier has infinitely-great gain, then velocity deviation can be zero basically.Yet in fact this is impossible.In order to adapt to therewith, Amplifier Gain can be increased to be eliminated because the operating lag that velocity deviation produces.Yet too big gain causes the unstability of control, and it plays adverse effect to total molded product quality.
So, a project of the present invention be that it is stable and high sensitivity can be provided for the control motor-driven injection molding machine provides a kind of control system.
A kind of control system of controlling motor-driven speed injector of the present invention comprises one by the injection member of driven by servomotor and the speed feedback control loop of a control servomotor.The speed feedback control loop comprise one with detect the servomotor rotary speed as the rotation speed sensor of measuring velocity amplitude, one in order to produce the amplifier of command signal of expression servomotor torque instruction value and one in order to control the motor driver of servomotor according to torque instruction value according to measuring difference between a velocity amplitude and the speed value.
According to a kind of mode of the present invention, control system also comprises a pressure sensor, and it is arranged in the drive system of injection cylinder inside spin configuration, in order to the pressure that detects resin and produce the pressure signal of measuring that pressure is measured in an expression; A masking amplifier, it is connected with pressure sensor and amplifies the pressure signal of measuring and produces the corrected value of an amplifying signal as torque instruction value; And an adder, it is connected with masking amplifier with amplifier and with torque instruction value and corrected value addition, makes addition result add to motor driver.
According to another kind of mode of the present invention, control system comprises a differentiator, is used for speed value is differentiated to calculate acceleration and to take advantage of a pre-determined factor to make the acceleration multiplication of calculating, and the multiplication result of generation is as the corrected value of torque instruction value; And adder; It is connected with differentiator with amplifier, adds to the torque instruction value that is produced by amplifier in order to the result that will double, and makes the result of addition add to motor driver.
Description of drawings
Fig. 1 is the schematic views of the injection member structure of a motor-driven injection molding machine;
Fig. 2 is the block diagram of the speed feedback control loop structure of a routine;
Fig. 3 illustrates Fig. 2 speed feedback control loop medium velocity command value and measures the characteristic curve of velocity amplitude as the function of time;
The pressure characteristic of Fig. 4 for being measured by load shown in Figure 1 unit, characteristic curve wherein are to draw with the time reference identical with Fig. 3;
Fig. 5 is the block diagram of the speed feedback control loop structure of first embodiment of the invention;
Fig. 6 illustrates Fig. 5 speed feedback control loop medium velocity command value and measures the characteristic curve of velocity amplitude as the function of time;
The pressure characteristic of Fig. 7 for being measured by load shown in Figure 1 unit, characteristic curve wherein are to draw with the time reference identical with Fig. 6;
Fig. 8 is the block diagram of the speed feedback control loop structure of second embodiment of the invention; And
Fig. 9 illustrates Fig. 8 speed feedback control loop medium velocity command value and measures the characteristic curve of velocity amplitude as the function of time.
For the ease of the present invention is understood, the injection member of using motor-driven injection molding machine of the present invention is described with reference to Fig. 1.In Fig. 1, the rotation of servomotor 10 is transferred into ball-screw 11.Nut 12 moves forward and backward according to the rotation of ball-screw 11.Nut 12 is fixed on the pressing plate 13 firmly.13 of pressing plates are installed on guide bar 14a and the 14b, and pressing plate 13 can be moved along guide bar 14a and 14b.Guide bar 14a and 14b firmly are fixed on (not shown) on the frame of injector.Moving forward and backward by a rotating shaft 15 of pressing plate 13 is sent to a screw rod 16.Screw rod 16 is arranged in the injection cylinder 17.Rotating shaft 15 is driven by a unshowned rotary drive mechanism rotation.Therefore, between end of rotating shaft 15 and pressing plate 13, a bearing 18 is set.Contiguous bearing 18 is provided with a load unit 19.Load unit 19 is used to detect the active force that during mold pressing resin press-resin acts on screw rod 16.
Mold pressing resin generally comprises multistep technology, promptly prepares resin, filling, pressurize and cooling.In preparing process, the resin of fusion is loaded in the injection cylinder 17, in fill process, by screw rod 16 is moved forward in injection cylinder 17 resin of fusion is inserted in the mould.In pressurize technology, apply a pressure to realize mold pressing to the molten resin of inserting mould.At this moment, measure as active force through load unit 19 to the molten resin applied pressure by screw rod 16.Measuring pressure by load unit 19 amplifies and access controller 21 through load unit amplifier 20.
Pressing plate 13 is provided with a position sensor 22, in order to detect the displacement of screw rod 16.Position sensor 22 produces a position sensor signal.Position sensor signal is through amplifier 23 amplifications and deliver to controller 21.Controller 21 sends the torque instruction value of above-mentioned each process to a speed feedback control loop 24 according to the disposal of being done by an arithmetic unit.24 controls of speed feedback control loop are the drive current of the servomotor 10 of foundation with the torque instruction value, with the output torque of control servomotor 10.
With reference to Fig. 2 the speed feedback control loop of routine is described simultaneously.Speed feedback control loop 24 comprises an amplifier 24-1, motor driver 24-2, a rotation speed sensor 24-3 and a subtracter 24-4.Amplifier 24-1 has the various functions that comprise PID (PID action) compensation.Amplifier 24-1 amplifies a speed command signal, and this signal indication produces the speed value Vr of the torque instruction value of servomotor 10.Speed command signal is from a master control unit (not shown) of motor-driven injection molding machine.Motor driver 24-2 drives servomotor 10 according to the torque instruction value by amplifier 24-1 output.The rotating speed that rotation speed sensor 24-3 detects servomotor 10 produces a rotation speed sensor signal, the velocity amplitude Vf that its expression is measured.Subtracter 24-4 is arranged on input one side of amplifier 24-1 and deducts the velocity amplitude Vf that measures from speed value Vr.The difference result that subtracter 24-4 produces transports to amplifier 24-1.Injector is total describing with label 30 in Fig. 2.Can be with the rotating speed of known rotating speed observer detection servomotor 10 without speed probe 24-3.This is because the rotating speed of servomotor can be determined by electric current that is added on servomotor 10 and magnitude of voltage.
Because the natural characteristic of resin that will be molded, speed feedback control loop as shown in Figure 2 may produce perturbation load during time interval T1 shown in Figure 3.When producing, perturbation load is reflected on the velocity amplitude Vf that speed probe 24-3 measures.Consequently, in subtracter 24-4, produce speed value Vr and measure deviation between the velocity amplitude Vf.For reference is provided, Fig. 4 illustrates the variation of the pressure P f that is measured by load unit 19.
Much less, velocity deviation is more little desirable more.The loop gain of speed feedback control loop, i.e. the gain of amplifier 24-1 can make its increase for the deviation that underspeeds.Yet bigger gain can cause the instability of speed feedback control loop.
The output that is added on the amplifier 24-1 of motor driver 24-2 is to be used to follow speed value Vr torque instruction value afterwards.Under such a case shown in Fig. 3, during the time interval T3 of time interval T2 that quickens or deceleration, need respectively to quicken or the torque of slowing down is quickened servomotor 10 or slowed down.Torque instruction value is produced by amplifier 24-1, this just need to amplifier 24-1 one speed value Vr is provided and the velocity amplitude Vf that measures between difference, i.e. velocity deviation.This just means velocity deviation occurs when one torque of servomotor 10 needs.Therefore can be with the index of velocity deviation as the speed feedback control loop response.
Preferably velocity deviation is less for responding preferably.Get on very well in principle, as long as amplifier 24-1 has infinitely-great gain, velocity deviation just can be zero substantially.Yet in fact this is impossible.In order to adapt to this situation, the gain that can increase amplifier 24-1 is to eliminate the operating lag that is produced by velocity deviation.Yet too big gain can cause control unstable, and it can play adverse effect to final molded product quality.
With reference to Fig. 5 first embodiment of the invention is described.First embodiment is applied to the injection member that Fig. 1 illustrates.Like among Fig. 5 and parts are to represent with the same label among Fig. 2.In this first embodiment, pressure sensor 31 is that the load unit that is provided with in screw rod 16 (Fig. 1) drive system by injector 30 realizes.For example, pressure sensor 31 can be arranged in order to the pressing plate 13 of transmission driving force and a parts place between the spiral 16.When molten resin is inserted mould and during by screw rod 16 compression, pressure sensor 31 detects the injection pressure that is produced.A masking amplifier 32 amplifies the pressure sensor signal that is produced by pressure sensor 31.The pressure sensor signal that amplifies is sent to the adder 33 that is arranged between amplifier 24-1 and the motor driver 24-2.Adder 33 with the output of the output of amplifier 24-1 and masking amplifier 32 mutually adduction addition result is transported to motor driver 24-2.
For this reason, motor driver 24-2 is provided with the torque instruction value of servomotor 10, promptly adds the output of amplifier 24-1 of the output of masking amplifier 32.This means and use the force value that records by pressure sensor 31 to proofread and correct the torque instruction value that is sent to motor driver 24-2.Obviously as seen can make speed value Vr and measure from Fig. 6 the correction like this of torque instruction value and reach stable, highly sensitive without any deviation between the velocity amplitude Vf.Even this stablely and highly sensitive when the phase in the time interval of Fig. 6 T11 produces perturbation load because of the essence of the resin that is molded and characteristic, still can realize.For reference is provided, Fig. 7 illustrates the pressure that is recorded by pressure sensor 31, and pressure wherein is converted into the thrust that is obtained by ball-screw 11.
Can replace by pressure sensor 31 in conjunction with the described load of Fig. 1 unit 19.Masking amplifier 32 amplifies the pressure sensor signal of being sent here by pressure sensor, preferably has different gains with motion backward forward for screw rod 16.More particularly, when screw rod 16 moved forward, promptly when injection pressure increased, the gain of masking amplifier 32 should be first gain G 1.On the other hand, when moving behind the screw rod 16, promptly when injection pressure reduces, the gain of masking amplifier 32 should be second gain G 2 (G1＞G2) wherein.First and second gain G 1 and G2 are that the transmission efficiency according to drive transmission device in the injection member determines.
With reference to Fig. 8 the second embodiment of the present invention is described.Second embodiment is characterised in that a differentiator 40 and an acceleration restrictor 41 is set in speed feedback control loop described in conjunction with Figure 2.More particularly, the variation of differentiator 40 detection speed command value Vr.Differentiator 40 usefulness predetermined coefficient K take advantage of detected value to produce multiplied result.Multiplied result is sent to adder 42 through acceleration restrictor 41.Adder 42 with the output of multiplied result and amplifier 24-1 mutually adduction addition result is sent to motor driver 24-2.Acceleration restrictor 41 is for a more detailed description below.
In injector, make rotary inertia constant by servomotor 10 drivings of injection member.Thereby servomotor 10 required acceleration torque and deceleration torques have a steady state value, i.e. acceleration with respect to the change of speed value Vr.For this reason, just might extrapolate required accelerating torque and deceleration torque in advance with regard to speed value Vr.Can carry out this reckoning according to the constant advantageous characteristic of rotary inertia that driven by injection member servomotor 10.Can obtain torque instruction value Tr through following steps.COEFFICIENT K is extrapolated in advance, and it is the inertia of injector, calculates then as the change of the speed value Vr of differential value and by differentiator 40 usefulness COEFFICIENT K and takes advantage of differential value.The torque instruction value Tr that calculates transports to motor driver 24-2 through adder 42 and instruction value additions.The result of addition delivers to motor driver 24-2.This has just eliminated the necessity of velocity deviation, and as shown in Figure 9, can access the speed feedback control loop without any operating lag.
The function of acceleration restrictor 41 then, is described.In motor-driven injector, speed feedback control loop as shown in Figure 8 not only can be used for control rate, but also can be used for comprising injection pressure control system or various other controls of the local circuit of the position control system of screw rod 16.It makes inertia that the acceleration range of motor-driven injector can produce from servomotor and the torque capacity and learns in advance.Might obtain such speed feedback loop, it follows the speed value Vr within a specific change rate scope (or a specific acceleration scope).It is realized as limiting value torque-limiting command value Tr with the higher limit and the lower limit of acceleration.Be preferably in addition, pre-determined factor and predetermined acceleration scope are that the torque inertia at servomotor becomes under the minimum situation and makes.
Claims (5)
1. control system that is used to control motor-driven injection molding machine; comprise a injection member and a speed feedback control loop that is used to control servomotor by driven by servomotor; described speed feedback control loop comprises that one is used to detect the servomotor velocity of rotation as the speed probe of measuring velocity amplitude; an amplifier that is used for according to the command signal of measuring the difference generation expression servomotor torque instruction value between a velocity amplitude and the speed value that obtains by described speed probe; and motor driver that is used for according to torque instruction value control servomotor; described control system is characterised in that it also comprises:
A pressure sensor, it is arranged in the drive system of a helical arrangement in the injection cylinder, also produces the pressure signal of measuring that pressure is measured in expression in order to the pressure that detects resin;
A masking amplifier, it links to each other with described pressure sensor and amplifies and measure the corrected value of amplifying signal of pressure signal generation as torque instruction value; And
Adder, it links to each other with described masking amplifier with described amplifier and makes the corrected value addition of torque instruction value and torque instruction value, and the result of addition is sent to described motor driver.
2. according to the described a kind of control system that is used to control motor-driven injection molding machine of claim 1; it is characterized in that; described masking amplifier is measured pressure signal with 1 amplification of first gain G when screw rod moves forward; measure pressure signal with 2 amplifications of second gain G when screw rod is mobile backward, second gain G, 2 to the first gain G 1 are little.
3. control system that is used to control motor-driven injection molding machine, comprise an injection member and the speed feedback control loop that is used to control servomotor by driven by servomotor, described speed feedback control loop comprises that one is used to detect the servomotor velocity of rotation as the speed probe of measuring velocity amplitude, an amplifier and a motor driver that is used for according to torque instruction value control servomotor that is used for according to the command signal of measuring the difference generation expression servomotor torque instruction value between a velocity amplitude and the speed value; Described control system is characterised in that it also comprises:
A differentiator is used for the differential speed value and calculates acceleration and take advantage of the acceleration that is calculated with a predetermined coefficient, and the multiplied result of generation is as the corrected value of torque instruction value; And
An adder, it links to each other with described differentiator with described amplifier, in order to multiplied result and the torque instruction value addition that is produced by described amplifier, addition result is sent to motor driver.
4. according to the described a kind of control system that is used to control motor-driven injection molding machine of claim 3; it is characterized in that; it also comprises an acceleration restrictor that is connected between described differentiator and the described adder, and described limiter only allows a signal in the predetermined acceleration scope by described limiter.
5. according to claim 3 or 4 described a kind of control systems that are used to control motor-driven injection molding machine, it is characterized in that pre-determined factor and predetermined acceleration scope are that the torque inertia at servomotor becomes under the minimum situation and makes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97112178A CN1073918C (en) | 1997-06-13 | 1997-06-13 | Control system for controlling motor-driven injection molding machinewith improved response |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97112178A CN1073918C (en) | 1997-06-13 | 1997-06-13 | Control system for controlling motor-driven injection molding machinewith improved response |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1202414A CN1202414A (en) | 1998-12-23 |
| CN1073918C true CN1073918C (en) | 2001-10-31 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97112178A Expired - Fee Related CN1073918C (en) | 1997-06-13 | 1997-06-13 | Control system for controlling motor-driven injection molding machinewith improved response |
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| Country | Link |
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| CN (1) | CN1073918C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100383829C (en) * | 2006-05-10 | 2008-04-23 | 北京航空航天大学 | Resin pressure collecting system of hot-forming process for composite material |
| CN102734452A (en) * | 2011-04-07 | 2012-10-17 | 鈊象电子股份有限公司 | Method for automatically correcting operating speed of game machine board |
| CN102564672B (en) * | 2012-02-28 | 2017-02-15 | 昆山爱都思电子科技有限公司 | Constant torque servo amplifier |
| JP6100051B2 (en) * | 2013-03-26 | 2017-03-22 | 住友重機械工業株式会社 | Injection molding machine |
| CN103407132B (en) * | 2013-08-27 | 2015-06-24 | 罗军 | Injection device of injection molding machine |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0752210A (en) * | 1993-08-11 | 1995-02-28 | Fanuc Ltd | Injection control device of injection molding machine |
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1997
- 1997-06-13 CN CN97112178A patent/CN1073918C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0752210A (en) * | 1993-08-11 | 1995-02-28 | Fanuc Ltd | Injection control device of injection molding machine |
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| Publication number | Publication date |
|---|---|
| CN1202414A (en) | 1998-12-23 |
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