JPS63216111A - Drive control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a drive control device that controls the position and speed of a movable object, and in particular, a drive control device that controls the position and speed of a movable object according to a command speed using a servo motor driven by a command pulse train. The present invention relates to a drive control device that stabilizes operation from high speed to low speed by switching modes.

[Prior Art] The drive mechanism for constant-speed feed of the stage of a conventional semiconductor exposure apparatus also serves as a high-speed positioning operation, and the stage position is detected and fed back.

[Problems to be Solved by the Invention] However, according to such conventional technology, the elasticity and viscosity that exist between the driving part such as a motor and the driven part such as the stage cause a problem between the servo motor and the stage. However, as exposure patterns become more precise, these vibrations and deviations are becoming a problem.

SUMMARY OF THE INVENTION In view of the problems of the prior art described above, the main object of the present invention is to improve the fidelity of following speed and position command values in a drive device.

[Means and operations for solving the problems] In order to solve the above problems, the present invention provides a drive control device that controls a drive part to control the position and speed of a driven part. A position detecting means is provided in each of the sections, and the outputs thereof are weighted and fed back.

[Example] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 shows a drive control device machine according to an embodiment of the present invention (
The configuration of the drive) system is shown. In the figure, 1 is a constant speed feed servo motor, 2 is a tacho generator directly connected to motor 1, 3 is a worm gear, 4 is an ohm wheel connected to gear 3, 5°11 is a clutch, 6, 7.12 is a gear, 8 is a rotary encoder directly connected to the gear 7, 9 is a servo motor for high-speed position control, and lO is a tachogenerator directly connected to the motor 9. In addition, 13 is a ball screw, 14
15 is a shaft, 16 is a load connected to the shaft 15, and 17 is a linear scale.

This drive system produces rotational torque by means of a servo motor 1.9. The torque produced by servo motor 1 is
It is transmitted through a worm gear 3 to a worm wheel 4 with a rotation ratio of 1/40. The ohm wheel 4 and the clutch 5 are connected by a shaft, and when the clutch 5 is connected, the rotational torque is directly transmitted to the gear 6.
When not connected, only the upper plate of the clutch 5 rotates. The rotation of gear 6 is transmitted to gear 7 connected to gear 6 at a rotation ratio of 1/1. Gear 7 is connected to rotary encoder 8 and ball screw 13. On the other hand, the torque produced by the servo motor 9 is
1 to the gear 12 in the same manner as the clutch 5. Gear 12 is connected to gear 7 at a rotation ratio of 1/2. Here, control is performed so that the clutch 5 and the clutch 11 are not both connected or disconnected at the same time. The rotational torque transmitted to the ball screw 13 is converted from a rotational system to a linear system at a nut 14, and the linear system force from the nut 14 moves a load 16 connected by a shaft 15. A linear scale 17 is attached to the load 16.

FIG. 2 is a block diagram of a portion that electrically controls the system of FIG. 1. In the same figure, 18 is a CPU that sends commands to the entire system, 19 is an interface port, and 20.2
1 is a preamplifier for constant speed feeding and high speed positioning, 22 and 23 are servo drivers, 24 is a multipath connecting the CPU UlB and the interface port 19,
25 to 38 are signals (lines) for control.

In this configuration, when the CPU 18 issues a drive command including control mode, position, and speed commands, the interface port 19 receives these command values and signals 37.3 from the rotary encoder 8 and linear scale 17.
8, speed command signal 25 and position command signal 2
6 and servo motor 1.9 selection signals 27 and 28 are output. The speed command signal 25 is sent to the driver 22 or 23 via the preamplifier 20 or 21 enabled by the selection signal 27, 28, and the driver 22 receives it.
(or 23) outputs voltage to motor 1 (or 9), and adjusts the output based on voltage 33 (or 35) from tachogenerator 2 (or 10).

FIG. 3 is a block diagram of the systems shown in FIGS. 1 and 2 described above. However, in the dynamic system, parts showing complex transfer functions are omitted. Also, the fourth
The figure shows a model of the mechanical part of this system.

In FIG. 4, JM indicates the inertia of the rotation system made up of the rotor and gears in the motor 1 (or 9), TM indicates the force that attempts to drive this, and M indicates the mass of the stage (load 16). Further, the mass M and the inertia J8 are connected by a ball screw having a spring constant. Between the mass iM and the inertia JM and the fixed part, and between the mass M and the inertia JM, there are CLs, respectively.
There is viscosity with values lCM and CG. Here, the rotation system/linear system conversion constant is α, and the positions of inertia JM and mass M are respectively θ. and xL,
The equation of motion for this system is as follows.

+ak (aθ, -xL) ==TM ・・・・・・(1) +k (between xL-α0) = 0 ・・・・・・(2) However, a dot (゛) placed on a variable means differentiation.

From equations (1) and (2), T. The transfer function from to X is (3). However, A=JM −M B”JM (Co/a2+cL)+M (CM +Cc
l )C= (JM+α' M)k+ (CMCL+C
M.C.

/α2+C11Ct,) D=(CM+α2CL　’)k E=C(1/α F=α , and S represents the Laplace operator.

Furthermore, in comparison with this equation (3), FIG. 5 shows a model when the spring constant of the mechanical system is not included, that is, when the system is viewed as one rigid body. In this case, viscosity C exists in a rigid body that has both a rotating inertia core and a linear mass M, and when these are driven by the input torque TM, the output xL changes. In this case as well, if we calculate the transfer function, we get xL α...
...(4) becomes. Comparing this with equation (3), equation (3) becomes (4
) is multiplied by the second-order lag element.

Therefore, in the circuit shown in Figure 3, in order to compensate for this delay,
The circuit within the frame 66 takes the difference between Xt and 02, and applies negative feedback as a viscous term.

Next, the positioning operation of the apparatus shown in FIG. 3 will be explained according to the flowchart shown in FIG.

After starting the positioning operation and performing initialization such as home alignment (step 101), when the target position command and (maximum) speed command are received from the multipath 24 (step 102), the CP 018 receives these values. To calculate the deceleration position, step 103) and transfer this to the I/F board 19.
The maximum speed command value is latched in the deceleration position register 42 and the maximum speed command value is latched in the maximum speed register 43 (step 104).
, sends a start command to the control circuit 44 (step 105
).

Then, the control circuit 44 reads the value of the speed pattern ROM 45 and sends the speed value to the sequential multiplication type D/A 48. This value is multiplied by the value latched in the maximum speed register 43 from the multiplication type D/A 46, and is input to the V/F converter 47, where it is converted into a pulse train speed command.

On the one hand, this signal is converted into an analog speed command signal via an F/V converter 48 and is supplied to the positive input terminal of a subtraction circuit 49. The subtraction circuit 49 subtracts this signal from the speed signal generated from the pulse train from the linear scale 17 via the F/V converter 50, and outputs an error voltage. This error signal is amplified by a linear amplifier 2° having a predetermined gain, and then sent to a servo driver 2.
2 is input. In addition, in the process until this error voltage is input to the servo driver 22, the signal from the rotary encoder 8 is F/V converted and the linear scale 1
The difference between the F/V converted signal from 7 is the subtraction circuit 5.
Feedback was provided after 2.51.

On the other hand, the speed command signal of the pulse train is input manually to the target position counter 55. The subtraction circuit 56 calculates the difference between the counted value of the counter 55 and the counted value of the current position counter 61 that counts the pulse train from the linear scale 17. This difference value is converted into analog by a D/A converter 57 and amplified by a linear amplifier 58 with a predetermined gain.

This output of the amplifier 58 is sent to the linear amplifier 2 by the adder circuit 59.
It is added to the output of 0 and fed forward to the input voltage of the servo driver 22. The driver 22 drives the motor 1 according to the input terminal, and the rotational torque moves the load 16 as described above.

In this way, after the load 16 is accelerated to the maximum speed while being fed back in step 106, the load 16 moves at the maximum speed until it reaches the deceleration start position. Deceleration position latch 42 and current position counter 61
When it is determined that the load 16 has reached the deceleration start position based on the output value of (step 107), the ROM 45 is
is decelerated based on the speed pattern of (step 108),
Then, a target position counter 55 and a current position counter 61
When it is determined that the target position has been reached based on the output value of (step 109), the drive is stopped and positioning is performed (step 110).

The operations in steps 102 to 110 above are repeated depending on the number of positions to be determined.

Note that the feedback from the rotary encoder of the drive unit and the feedback from the linear scale described above can also be applied to constant speed feed, but in this case,
It is necessary to use these weightings at the time of feedback depending on the speed command value.

FIG. 7 is a graph showing a time response waveform obtained by calculation when drive control is performed by the apparatus of this embodiment as described above. In other words, this graph represents the response waveform to the human step force when the control method of the above-mentioned embodiment is applied, and it is clear that the control is more effective than in the case of the conventional control method as represented by the response waveform shown in FIG. It can be seen that the responsiveness of the system has been improved. The graphs in FIGS. 7 and 8 are based on the apparatus shown in FIG. 1, when the mass of the carriage (driven object) is 300 kg and the resonance frequency is 63
The case of Hz is shown.

[Effects of the Invention] As explained above, according to the present invention, position detection means are provided in the driving part and the driven part, and by taking in the output values or deviations from these detection means and controlling the drive,
It is possible to suppress the time delay in mechanisms with complex mechanical transmission systems.

[Brief explanation of the drawing]

FIG. 1 is a sketch of a mechanical system of a drive control position i according to an embodiment of the present invention, FIG. 2 is a sketch of an electrical system for controlling the mechanical system of FIG. 1, and FIG. A block diagram summarizing the systems in Figures 1 and 2, Figure 4 is a model of the mechanical system, and Figure 5 is:
A model diagram when the mechanical system is regarded as one rigid body. FIG. 6 is a flowchart showing the operation of the device in FIG. 3. FIG. 7 is a diagram showing the operation of the device in FIG. A graph showing a time response waveform when the characteristics are improved by control, and FIG. 8 shows a time response waveform due to conventional drive control. 1: Constant speed feed servo motor, 2: Tacho generator, 3: Worm gear, 4: Worm wheel, 5, 11: Clutch, 6.7, 12: Gear, 8 two-rotation encoder, 9: Servo motor, lO: Tacho Generator, 13: Ball Neshi, 14: Natsu, 15
: Shaft, 16: Load, 17: Linear scale, 18
:cPU. 19: Interface port, 20.21: Preamplifier, 22.23: Servo driver, 24: Multibus, 25
: Speed command signal, 26: Position command signal, 27.28
: Servo motor selection signal, 33, 35: Voltage from tacho generator, 37: Signal from rotary encoder, 38: Signal from linear scale. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Tetsuya Ito Figure 2 Figure 4 Figure 7

Claims (1)

[Claims] 1. A driven part, a driving part that drives the driven part, a first detection means that detects the position of the driving part, and a second detection means that detects the position of the driven part. A drive control device comprising: detection means; and control means for controlling the drive section to control the speed and position of the driven section. 2. The drive control device according to claim 1, wherein the drive section includes a high-speed positioning motor, a constant-speed feed motor, and a clutch that switches the connection state of these motors to use them properly. 3. The drive control device according to claim 1, wherein the control means includes means for weighting and feeding back the outputs from the first and second detection means, respectively. 4. A patent in which the drive section has a high-speed positioning motor and a constant-speed feed motor, and the control means selectively weights signals from these motors and the first and second detection means depending on the driving state. A drive control device according to claim 1.