JP2011205842A - Drive controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive controller for controlling the position of a mechanical end with high accuracy by smoothly switching between semi-closed loop control and full-closed loop control, in a device including an actuator-driven movable part, with respect to a nonlinear system.SOLUTION: A servo amplifier (the drive controller) 3 includes: a motor-end sensor 2 detecting the position of the rotation of a motor 4; a semi-closed loop control means performing semi-closed loop control on the motor 4; a mechanical-end sensor 8 detecting the position of a mobile body 9 moved in a nonlinear path; a full-closed loop control means performing full-closed loop control on the motor 4 on the basis of the position of the mobile body 9; a switch 30 for selecting a semi-closed speed command or a full-closed speed command; and a speed limiter 31 mounted in a stage subsequent to the switch 30 for limiting the speed commands within a predetermined value and absorbing the fluctuations of the speed commands in switching the control.

Description

  The present invention is a drive device for positioning a moving body by controlling a motor that drives a moving body having a non-linear element, and in particular, switching between semi-closed (hereinafter referred to as semi-micro) control and full-closed (hereinafter referred to as full-chromo) control during movement. The present invention relates to a drive control device that performs control.

  Conventionally, when the device is driven by transmitting the rotational force of the motor with a transmission means such as a belt or a ball screw, and in the control for positioning the machine end, when switching between semi-micro control and full-chromo control, it is near the target position. The speed command value generated by the position control system multiplied by a predetermined value is used as the speed command value for the speed control system, or when the speed command value falls below the actual speed of the motor, There has been proposed one that switches a control method to a position control system. This control method operates so as not to cause a change in responsiveness viewed from the command response time (see, for example, Patent Document 1).

  In addition, as a means to control the final target position of the machine end with high accuracy, a control method is proposed in which the machine end sensor is arranged only in the area where high positioning accuracy is required, and switching between micro control and full-chromo control near the final target position is proposed. (For example, refer to Patent Document 2).

JP 2005-11004 A Japanese Patent Laid-Open No. 11-272335

  The feature of semi-micro control is that the current motor position and rotation speed can be detected from the motor position feedback signal from the motor position detector (hereinafter referred to as encoder), and the motor can be directly controlled with respect to the motor position feedback signal. Therefore, it is easy to control even if a relatively high gain is set, but the positioning accuracy of the machine end depends on the machine accuracy. For example, in a system configuration in which a ball screw is connected to a motor and a table on the ball screw is positioned, the positioning accuracy of the machine end largely depends on mechanical play such as backlash between the ball screw and the table. For this reason, the micro control has a disadvantage that it is difficult to control the machine end position with high accuracy.

  On the other hand, the feature of full-chromo control is that high-precision positioning control can be performed by directly detecting and controlling the machine end position with a machine end sensor such as a scale. There is a disadvantage that the control gain cannot be increased and the response is inferior to that of the micro control.

  In order to utilize the features of the above-described semi-micro control and full-chromo control, the control switching method described above has been proposed. However, when the drive control device is used for a non-linear mechanism such as a link mechanism, there is no proportional relationship between the motor speed and the machine end speed, so a feedback signal (hereinafter referred to as fb signal) in semi-micro control and fb in full-chromo control. There is no continuity with the signal, and when switching, the speed changes and a mechanical shock occurs. Therefore, in order to realize the switching between the semi-micro control and the full-chromo control without mechanical shock in the non-linear mechanism, there has been a problem that the control must be switched after the motor is stopped, for example.

  The present invention has been made in view of the above, and has improved the response and accuracy of machine end position control for nonlinear mechanisms such as a link mechanism, and reduced mechanical shock when switching from semi-micro control to full-chromo control. An object of the present invention is to provide a drive control device that can be realized.

  In order to achieve the above-described object, the drive control device of the present invention is a drive control device that positions a moving body by controlling a motor that drives the moving body with respect to the moving body having a non-linear mechanism. Including a motor end sensor for detecting the position, including a micro control means for controlling the motor in accordance with a micro speed command generated based on the rotational position of the motor, and a machine end sensor for detecting the position of the moving body. A full-chromo control means for performing full-chromo control of the motor based on a full-chromo speed command generated based on the position; a selector switch for selecting either the micro-speed command or the full-chromo speed command and switching between the micro control and the full-chromo control; and a switch It is provided in the subsequent stage, and by limiting the speed command to a predetermined size or less, semi-micro control and full-chromo control Characterized in that a speed limiter for absorbing the fluctuations in the speed command when the control switching between.

  According to the present invention, the speed limiter is provided at the subsequent stage of the changeover switch, and absorbs fluctuations in the speed command when the control is switched between the semi-micro control and the full-chromo control by limiting the speed command to a predetermined magnitude or less. With this speed limiter enabled, the control is switched from the semi-micro control to the full-chromo control. Therefore, at the time of switching from semi-micro control to full-chromo control, there is a deviation (motor end position deviation) between the semi-micro command position and the semi-micro position fb signal generated by the semi-micro control, and the full-black command position and full-cro position fb signal generated by the full-chromo control. Regardless of the magnitude of the deviation (machine end position deviation), speed fluctuation is suppressed by the speed limiter, so continuous switching from semi-micro control to full-chromo control is possible, and the operation time of the device can be shortened. .

FIG. 1 is a block diagram showing the configuration of an embodiment of a drive control device for positioning control of a link mechanism as a nonlinear moving body of the present invention. FIG. 2 is a diagram illustrating the link mechanism shown in FIG. 1 in a simplified manner. FIG. 3 is a diagram for explaining changes in the motor rotation amount, the nut movement amount, and the link movement amount of the link mechanism shown in FIG. FIG. 4 is a view for explaining the nut moving speed and the link moving speed at the nut position of the link mechanism shown in FIG. FIG. 5 is a correlation diagram between the speed command value of the micro control and the full black control and the machine end position, and is a diagram for explaining the conventional method. FIG. 6 is a correlation diagram between the speed command value of the micro control and the full black control and the machine end position, and is a diagram for explaining the switching method of the present embodiment. FIG. 7 is a diagram for explaining the effect of the present embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments of a drive control apparatus for controlling a machine end by switching between semi-micro control and full-chromo control of an apparatus having a link mechanism according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment FIG. 1 is a block diagram showing the configuration of an embodiment of a drive control apparatus of the present invention, and shows a drive control apparatus that controls the positioning of a link mechanism as a nonlinear moving body. In FIG. 1, a motor 4 is an actuator that drives a link mechanism 7. In the present embodiment, a permanent magnet servomotor is used as the motor 4.

  The motor 4 is configured to transmit a rotational force from the timing pulley to the ball screw 6 via the belt 5. A link mechanism 7 is connected to the ball screw 6 through a nut on the ball screw 6. 1 moves to the left and right in FIG. 1 to move the moving body 9 which is the machine end of the link mechanism 7. The position of the moving body 9 as the machine end is a target for positioning control.

  The motor 4 is driven by a servo amplifier (drive control device) 3. The servo amplifier 3 drives the motor 4 based on the motor end position command (16) cs and the machine end position command (19) cf output from the host controller 50.

  A motor end sensor 2 that detects the speed and position of the motor 4 is attached to the motor 4. The motor end sensor 2 inputs a motor end speed fb signal and a motor end position fb signal to the servo amplifier 3. In the present embodiment, the motor end sensor 2 generates the motor end position fb signal rs as an example.

  The machine end sensor 8 is a sensor attached along the movement path of the moving body 9, and is specifically a non-contact type or contact type linear scale that detects the position of the moving body 9. The machine end sensor 8 is machine end position information obtained based on observation of the machine end (moving body 9) in the link mechanism 7, and generates a machine end position fb signal rf used in full-chromo control. In the present embodiment, the machine end sensor effective signal 21 for identifying that the machine end position fb signal rf has been established is provided in the machine end sensor 8. It can be generated from the state of the fb signal rf.

  The servo amplifier 3 includes semi-closed loop control means and full closed loop control means. The semi-closed loop control means includes a position deviation calculation unit (first position deviation calculation unit) 35, a position gain (PG) 27, a micro / full-color switch 30, a speed limiter 31, a speed deviation calculation unit 37, a speed gain ( VG) 33, the current control unit 34, and the motor end sensor 2 form a control loop. On the other hand, the fully closed loop control means includes a position deviation calculation unit (second position deviation calculation unit) 36, a position gain (PG) 27, a constant gain (K) 28, a micro / full-color changeover switch 30, a speed limiter 31, a speed. A deviation calculation unit 37, a speed gain (VG) 33, a current control unit 34, and a machine end sensor 8 are included to form a control loop.

  The position deviation calculation unit 35 subtracts the motor end position fb signal rs obtained by the position detector from the motor end position command value (final target position) 16cs to calculate the sem micro position deviation (first position deviation) Es. . Further, the position deviation calculation unit 36 subtracts the machine end position fb signal rf obtained from the machine end detector 8 from the machine end position command value (final target position) 19cf, and obtains a full-chromo position deviation (second position deviation). Ef is calculated.

  The motor end position command value cs and the machine end position command value cf used at this time are generated by the host controller 50. This process is expressed by equations (1) and (2).

Es = cs-rs (1)
Ef = cf−rf (2)

  The machine end position command 19 is a command value input at the time of full-chromo control, and is set to 0 in the present embodiment at the time of sub-micro control, but need not be limited to 0.

  A position gain (PG) 27 following the position deviation calculating unit 35 is a gain multiplied by the position deviation Es on the micro side and the position deviation Ef on the full-color side. Further, the full-chromo side deviation Ef is multiplied by a constant gain (K) 28 in series with the position gain (PG) 27. This constant K is used to convert the machine end position information into a motor position information unit system. In the present embodiment, the position gain is simplified, but an arbitrary controller can be used as a position controller at the position of the position gain PG.

  As a result of multiplying the micro-side position deviation Es and the position gain PG, a motor speed command value is generated. The micro control side speed command value (semi-closed speed command) is set to vcs, and the full-chromo side speed command value (full closed speed command) is set to vcf. This process is expressed by equations (3) and (4).

vcs = Es × PG (3)
vcf = Ef × PG × K (4)

  It is determined by the semi-micro / full-color change-over switch 30 which of the semi-control side speed command value vcs and the full-chromo side control command value vcf is used. This switch determines whether the micro side is turned on or the full black side is turned on by a micro / full-color switching command 14 from the host controller 50.

  Here, the host controller 50 can also apply the state of the machine end sensor valid signal 21 that is directly input from the machine end sensor 8 to the condition of the micro / full-color switching command 14. In this case, the above-mentioned machine end position command 19 receives a command value from the host controller 50 even during the micro control.

  Next, the motor end speed command value vcs or the machine end speed command vcf selected by the above-mentioned semi-micro / full-color changeover switch 30 is limited in the speed limiter 31 so as to be equal to or less than a predetermined magnitude.

  If the value exceeds the speed limiter set value (15) vlim set by the host controller 50 by the speed limiter 31, the speed limiter set value vlim is obtained. If the value is equal to or less than the speed limiter set value vlim, it is output without processing. This output signal is set as a speed command value vcmd. The method for selecting the speed command value vcmd is expressed by equations (5), (6), (7), and (8). In this example, the semi-micro speed command vcs is used, but at the time of full-chromo control, the semi-micro speed command vcs may be set to the full-black speed command vcf.

if vlim ≤ vcs (5)
vcmd = vlim (6)
if vlim> vcs (7)
vcmd = vcs (8)

  The speed limiter set value 15 vlim is a fixed value or variable set in the host controller 50, and the method for generating the set value is not limited. A difference between the selected speed command value vcmd and the motor end position fb signal rs is calculated as a speed deviation signal ve by the speed deviation calculation unit 37. The current control unit 34 causes a current i to flow through the motor 4 based on a current command signal Tc obtained by multiplying the speed deviation signal ve by a speed gain (VG) 33.

  FIG. 2 is a simplified diagram of the device 60 having the link mechanism of FIG. In order to simplify the description, the upper and lower sides of the link mechanism are freely movable. In FIG. 2, the first link 100 and the second link 101 are expanded and contracted by the lateral movement of the nut 102. When the length of the first link 100 and the second link 101 is L, and the link angle that changes depending on the position M of the nut is θ, the link movement amount is expressed by the following equation (9).

Link movement amount = 2 × L × (1-sin (acos (M / L))) (9)
Here, acos is an inverse function of cos.

  FIG. 3 shows changes in the motor rotation amount, the amount of movement of the nut 102, and the amount of link movement in the link mechanism of FIG. The nut movement amount is proportional to the motor rotation amount, whereas the link movement amount has a characteristic shown by a solid line because it includes a nonlinear element as a mechanism. This relationship is determined by the mechanism.

  FIG. 4 shows the moving speed of the nut 102 and the link moving speed at the nut position M in the link mechanism of FIG. As shown in FIG. 4, even if the nut moving speed is constant, the link moving speed is slow in the vicinity of the link angle θ = 90 ° (nut position 0 mm side) and moves as the link angle θ decreases (nut position 150 mm side). Increases speed. That is, since the change in the link movement amount with respect to the change in the motor movement amount varies greatly depending on the nut position M, the control amount in the servo amplifier varies greatly depending on the nut position M.

  In the present invention, in order to cope with such non-linearity, a speed limiter 31 is provided after the changeover switch 30 between the semi-micro control and the full-chromo control. Regardless of the calculation results of Equation (3) and Equation (4) due to the speed limiter, the speed limiter output becomes equal, so control from semi-micro control to full-chromo control over a wide range of movement without mechanical vibration Switching is possible. This will be described with reference to the correlation diagram between the speed command value and the machine end position in FIGS.

  First, the problem of the conventional method will be described with reference to FIG. In FIG. 5, the motor end speed command value vcmd is a broken line 43 when the machine operating range 40 is controlled only by the micro control. A broken line 44 is a motor end speed command when the machine operating range 40 is controlled only by full-chromo control.

  For example, when the semi-micro control and the full-chromo control are switched at the position 45 due to the difference in the motor speed command value vcmd, the speed command value vcmd changes suddenly as shown by a solid line, thereby generating mechanical vibration. For this reason, conventionally, in order to suppress mechanical vibration, switching between the micro control and the full black control at a point where the micro speed command and the full black speed command coincide with each other as in the position 42, or after the motor is stopped, the full micro control is performed. There was a need to switch to control. In the former case, a machine end sensor from the final target position to the position 42 is necessary, and it is necessary to use a machine end sensor having a long measurement range. In the latter case, since the motor is temporarily stopped for control switching, the positioning time is long.

  Next, FIG. 6 specifically shows the effect of the speed limiter 15 installed after the semi-micro control and full-chromo control changeover switch shown in FIG. 1, that is, the effect of the present invention. For example, when the set value of the speed limiter is set to the value at point 46 in FIG. 6, the speed command vcmd changes as shown by a solid line. Similarly to FIG. 5, even if the micro / full-color switch 30 in FIG. 1 is switched from the micro control to the full control at the control switching point 45, the speed command vcmd before and after the switching is constant at the speed limiter value 46. There is no fluctuation in the switch and it is possible to switch between micro control and full black control smoothly.

  Although FIG. 6 shows an example in which the speed limiter value vlim is a fixed value, it may be variable. FIG. 7 shows an example in which the speed limiter value is set to a fixed value set in advance and the larger one of the semi-micro speed commands. As shown in FIG. 7, the speed limiter value 46 becomes the semi-micro control command 43 until the position 47, and thereafter becomes the fixed value 46, so that the moving time can be shortened and the machine end sensor length from the position 42 to the final target position is set. It is possible to select the minimum machine end sensor that does not require positioning accuracy and that requires positioning accuracy.

  According to the present embodiment configured as described above, as a control method, positioning control that takes advantage of the advantages of both controls is performed in a nonlinear manner, instead of simply switching between semi-micro control and full-chromo control. It can be implemented in a device having a mechanism.

  As described above, according to the present embodiment, when mechanical end control of a mechanism having a nonlinear element is performed by switching between semi-micro control and full-chromo control, when the micro-position deviation Es and the full-chromo position deviation Ef are not equal. However, since the speed limiter absorbs the gap between the two, it is possible to continuously switch between the micro control and the full black control without stopping the motor. In addition, the positioning time can be shortened by making the setting value of the speed limiter variable.

  Also, since the micro-control and full-chromo control can be switched freely according to the setting of the speed limiter 31, it is possible to install the machine end sensor only in the part where positioning accuracy is required, improving the degree of freedom in machine design, The cost of the end sensor can be reduced.

  As described above, the drive control device according to the present invention is a drive control device that controls a device having a link mechanism by switching between semi-micro control and full-chromo control, and particularly for a device that requires high-precision control of a machine end. It is useful and suitable for a drive control device that drives a mechanism having a nonlinear element such as a press machine, an injection molding machine, or a machine tool.

2 Motor end sensor 3 Servo amplifier (drive controller)
DESCRIPTION OF SYMBOLS 4 Motor 5 Belt 6 Ball screw 7 Link mechanism 8 Machine end sensor 9 Moving body 14 Semi / full-color switching command 15 Speed filter set value 16 Motor end position command 19 Machine end position command 21 Machine end sensor effective signal 27 Position gain 28 Constant gain 30 Semi-micro / full-color switch 31 Speed limiter 33 Speed gain 34 Current control unit 35 Position deviation calculation unit (first position deviation calculation unit)
36 Position deviation calculation unit (second position deviation calculation unit)
37 Speed deviation calculation unit 40 Machine end operating range 42 Point that can be switched between micro control / full-color control 43 Speed control value at the end of micro control motor 44 Speed command value at full-chromo control motor end 45 Switching point of micro control / full-color control 46 Setting of speed limiter set value Point 47 Speed limiter variable point 50 Host controller 55 Speed controller 100 First link 101 Second link 102 Nut

Claims (3)

A driving device for positioning a moving body by controlling a motor that drives the moving body having a nonlinear mechanism;
A semi-closed loop control unit that includes a motor end sensor that detects a rotational position of the motor, and performs semi-closed loop control of the motor by a semi-closed speed command generated based on the rotational position of the motor;
A full-closed loop control means that includes a machine end sensor that detects the position of the moving body, and that performs full-closed loop control of the motor based on a full-closed speed command generated based on the position of the moving body;
A selector switch that selects either the semi-closed speed command or the full-closed speed command and switches between semi-closed loop control and full-closed loop control; A speed limiter that absorbs fluctuations in the speed command when the control is switched between semi-closed loop control and full-closed loop control.
A drive control device comprising: A driving device for positioning a moving body by controlling a motor that drives the moving body having a nonlinear mechanism;
A speed control unit for controlling the speed of the motor based on a speed command;
A motor end sensor that detects a rotational position of the motor and outputs a motor end position feedback signal;
A first position deviation calculating unit that calculates a first position deviation that is a difference between the motor end position feedback signal and a motor end position command value;
Semi-closed loop control that includes the speed control unit, the motor end sensor, and a first position deviation calculation unit, and performs semi-closed loop control of the motor by a semi-closed speed command generated based on the first position deviation Means,
A machine end sensor that detects a position of the moving body and outputs a machine end position feedback signal; and a second position that calculates a second position deviation that is a difference between the machine end position feedback signal and a machine end position command value. A deviation calculating unit;
A fully closed loop control that includes the speed control unit, the machine end sensor, and a second position deviation calculation unit, and performs full closed loop control of the motor based on a full closed speed command generated based on the second position deviation. Means,
One of the semi-closed speed command and the full-closed speed command is output to the speed control unit, and a changeover switch for switching between semi-closed loop control and full-closed loop control,
Between the semi-closed loop control and the fully closed loop control, the speed command is provided between the changeover switch and the speed control unit, and the speed command output to the speed control unit is limited to a predetermined magnitude or less. A speed limiter that absorbs fluctuations in the speed command when the control is switched,
A drive control device comprising: The drive control apparatus according to claim 1, wherein the moving body that moves along the non-linear path includes a link structure.

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