JPS62196405A - Controller of air motor - Google Patents

Abstract

PURPOSE:To improve the braking stop precision by calculating an air motor driving enumerated data on the bases of a current positional coordinates and a target movement position coordinates, compensating the enumerated data using the braking characteristics of the air motor, and then applying the air brake. CONSTITUTION:Turning a ball screw 3 by driving an air motor AM slides a moving element 6 along two guide rails 9 until stopped at a determined position by the operation of an air brake AB. When the air brake AB is applied by such controlling unit, both a current positional coordinates X and a movement target coordinate Y are read and then the turning direction of the air motor AM on the bases of said coordinates X and Y. An enumerated data Z by which the air motor AM is driven is calculated from both the current positional coordinates X and the movement target coordinates Y, and the enumerated data is compensated using the braking characteristics of the air motor AM to form a compensated enumerated data M. According to said data M, the air brake AB is controlled to operate.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a braking device for an air motor used in a control device such as a robot. It is related to the device. This type of technology can be used for braking control of robots or control devices in general.

[Prior Art] As a conventional braking method for an air motor, Japanese Patent Application No. 59-265146 and Japanese Patent Application No. 51-2, which were filed by the present applicant, are known.
The technique of No. 65147 can be mentioned. The technology of the above application relates to an automatic coating machine that performs coating by moving a coating gun according to the surface of an object to be coated, and particularly relates to a method of stopping an air motor for coating robots 1 to 1.

The gist of the former application is to provide a driving means comprising an X-axis moving air motor, a Y-axis moving air motor, and a Z-axis moving air motor for moving a coating gun, and a braking means consisting of air brakes for these axes. In a painting robot consisting of a moving means for moving these axes to move in three-dimensional space and a control circuit for controlling them, after the control circuit supplies air pressure to reverse the air motor by a certain amount, the braking means A method for stopping an air motor for a painting robot, characterized in that the air motor for a painting robot is brought into a stopped state by activating the air motor, and an air motor for moving an X-axis for moving a painting gun.
A driving means consisting of an air motor for Y-axis movement and an air motor for Z-axis movement, a braking means consisting of an air brake for these axes, a movement means for moving these axes in three-dimensional space, and In a painting robot consisting of a control circuit, during a teaching process in which the position, orientation, and operation of a painting gun are stored in a memory for each step, after the control circuit supplies air pressure to reverse the air motor by a certain amount, A method of stopping an air motor for a painting robot, characterized by activating a braking means to bring it to a stopped state.

In addition, the gist of the person @ is that the driving means consists of an air motor for moving the X-axis, the air motor for moving the Y-axis, and the air motor for moving the Z-axis, and the braking means consists of air brakes for these axes. , a painting robot consisting of a means of movement that moves in a three-dimensional space consisting of these axes, and a control circuit that controls them, based on data obtained in the teaching process in which the position of the painting gun is stored in memory for each step. , a method for stopping an air motor for a painting robot, characterized in that the braking distance by the air motor is calculated and control is performed to perform predictive braking.

The above method of stopping the air motor for a painting robot is intended for painting robots, and since the spraying angle from the painting gun is large, it is not necessary to have a highly accurate stopping position. The spread angle of the gun compensated for that.

[Problems to be solved by the invention] However, in painting that requires highly accurate spraying, the above-mentioned reverse braking or technology that predicts overrun from the travel distance does not necessarily require high precision. Accuracy cannot be expected. In particular, in the latter technique, since the coordinates of each position are controlled according to the home position, there is a problem in that the errors at each position are integrated, and the errors at later positions become larger.

High accuracy can be achieved by adding a braking circuit, for example, a separate microcomputer, to the microcomputer that executes the main program. However, as the braking precision becomes more sophisticated, the device becomes more expensive and the control circuit device becomes larger.

Therefore, in order to solve the above-mentioned problem, the present invention aims to provide a braking device for an air motor that improves braking accuracy without adding any additional parts.

[Means and effects for solving the problem] The braking device for an air motor according to the present invention includes a means for reading the current position coordinate [X], a means for reading the moving target coordinate [Y], and a means for reading the current position coordinate [X]. Air motor rotation direction determination means that determines from [X] and movement target coordinate [Y], and count value [Z] for driving the air motor that is calculated from the current position coordinate [X] and movement target coordinate [Y]. a drive counting means for obtaining a correction count value [M], a brake correction means for correcting the count value obtained by the drive counting means using the braking characteristics of the air motor to obtain a correction count value [M], and a correction count value [M] obtained by the brake correction means. M]
It is equipped with a braking means that activates an air brake at each position, and calculates the moving distance from the current position coordinate [X] by referring to the value of the movement target coordinate [Y] specified by the move command at each position. Furthermore, since the timing for braking the air motor is obtained by the correction count value [M] that matches the braking characteristics of the air motor, the current error must be corrected for each position before moving to the next position. I can do it.

[Embodiment] Fig. 1 is an overall circuit diagram of a braking device for an air motor according to an embodiment of the present invention, and Fig. 2 is a partially sectional front view of the main parts of the driving section and braking section of the position setting system. , FIG. 3 is a circuit diagram of the pneumatic circuit of the position setting system shown in the embodiment of FIGS. 1 and 2.

In the figure, the rotary encoder RE is a known rotation angle detector that magnetically or IC detects the rotation angle optically. The photo-electric conversion circuit BF, which inputs the output of the rotary encoder RE, is a buffer circuit that transmits the signal of the rotary encoder RE after temporarily cutting off the electrical connection, and is composed of a light emitting element and a light receiving element. The drive circuit DA consists of a driver circuit that excites the solenoids of various valves, and the solenoid 13 controls the air brake AS via the air brake valve BV. Similarly, the drive circuit DB or the drive circuit DC is connected to the solenoid 1.
The air motor AM is controlled by the air motor valve FR by the solenoid 1L and the solenoid 11R. Similarly, the drive circuit DD operates the high speed setting valve S with the solenoid 12.
The throttle valve 16 is controlled via V.

Further, the microcomputer CPU constitutes a control circuit, and although block circuits not directly related to the gist of the present invention are not shown, they execute control processing according to a main program of a device using a predetermined air motor.

Note that control of the drive section and brake section of the motor position setting system is processed in a subroutine.

In the main part front view with a partial cross section of the driving part and braking part of the position setting system shown in FIG. The ball screw 3, which is the moving shaft, is rotated via the air brake AB. A rotary plate 4 having a large number of slits is fixed to the coupling 2, and constitutes a rotary encoder RE for magnetically rotating and detecting the angle using the angle detecting section 5.

Note that the number of pulses of the rotary encoder RE and the moving distance with respect to the moving body 6 are set arbitrarily. The rotating plate 4 and the angle detecting section 5 are generally called an angle sensor or a rotation sensor, and are well known, so a description thereof will be omitted. Further, since the air motor AM and the air brake AB are similarly well known, their explanations will be omitted.

The air motor AM, air motor Ki AB, etc.
The other end of the ball screw 3 is fixed to a drive source support member 8.

These drive source support member 7 and drive source support member 8 are attached to an arm base (not shown). Further, the ends of two guide rails 9 are attached to the drive source support member 7 and the drive source support member 8. In this way, the two guide rails 9 are arranged in parallel on the arm base.

The moving body 6, which has a sliding part that slides on the guide rail 9 and a threaded part that screws into the ball screw 3, slides on the guide rail 9 by the ball screw 3 rotated by the air motor AM, and moves in a straight line according to the guide rail 9. Do exercise. Even when each of these configurations is attached to an arm base of a two-dimensional or three-dimensional axis, the configuration of the basic positioning means of each axis arm is the same for each axis.

Note that the moving body 6 is equipped with a painting gun and means for attaching the same when used for a target object, for example, a painting robot, depending on the manner of use thereof.

FIG. 3 is a circuit diagram of the pneumatic circuit of the position setting system shown in the embodiment of FIGS. 1 and 2, in which the air pressure supplied to the drive section of the arm base is controlled to open and close by solenoid 11L and solenoid 11R. It is supplied to the air motor valve FR, which consists of a boat 3-position valve. The air motor AM performs forward rotation when the solenoid 11L is driven, and performs reverse rotation when the solenoid 11R is excited. The rotational speed of the air motor AM is determined by the throttle valve 16 on the exhaust boat side of the air motor AM.
By opening and closing the high-speed setting valve SV, which is a position valve, the circuit of the throttle valve 16 can be bypassed.

Therefore, by energizing the solenoid 12.

Air motor AM will rotate at high speed.

On the other hand, the air pressure led to the pneumatic circuit of the braking section is reduced by the pressure reducing valve 15 and passed through the air brake valve BV, which is a 3-boat 2-position valve whose opening and closing are controlled by a solenoid 13 and a manual pushbutton switch. Guided by air brake AB. Normally, the reduced air pressure is guided to the air brake AB by the air brake valve BV and enters a braking state, thereby restricting the rotation of the air motor AM. When the air brake valve BV closes, the air pressure in the air brake 8B is discharged by the quick exhaust valve 14, and the air brake A
Release the brake state of B.

Note that the brake speed at this time is determined by a speed controller consisting of a check valve and a throttle valve.

4 and 5 are flowcharts of the motor subroutine j for driving and stopping the air motor of the air motor braking device according to the embodiment of the present invention.

During execution of program processing according to a normal control program, a move command for moving the air motor a predetermined distance causes the process to enter "motor subroutine j".

First, in step S1, the memory used in this "motor subroutine j" is initialized, and in step S2, the air brake AB is activated by the air brake valve BV.
The brake is released.

In step S3, the position [N
]'s current position coordinates [XN]. The moving counter counts the moving distance of the moving body 6 from the home position using the numerical value output from the rotary encoder RE.

In step S4, the moving target coordinates [YII+1] of position [N+1] are read from the memory stored by teaching and specified by the move command. Step S
Step 5: Select the position from the memory stored during teaching [
Subtract the current position coordinates [XN] from the moving target dust mark [YN+1] of [N+1], and calculate the air motor A from the positive/negative of that value.
Determine the direction of rotation of M, and if the value is positive, step S
6, count the number of output pulses of the rotary encoder RE that rotates forward, and set the movement value [ZN+1] of the increment memory that stores the counted value up to the next position to [Z
] −[Y] −[XN]i+i
Calculate as N+1. Then, in step S7, the solenoid 11L that performs forward rotation is energized, and the air motor valve B
Open V and rotate the air motor AM in the forward direction.

In step S5, the current position coordinate [XN] is subtracted from the moving target coordinate [Y, +11], and when the value is not positive, the solenoid 11R that performs reverse rotation is energized in step $8, and the increment when performing reverse rotation is Memory movement value [ZN+
1] to [Z] - [X] - [YN+1]N+I
Calculated as N. Then, in step S, the solenoid 11R for reverse rotation is energized, and the air motor valve BV is
Open and rotate the air motor AM in the opposite direction.

Step 810. In step S12, step S14, and step 816, the movement value [ZN
+1 is corrected to match the braking characteristics of air brake AB.

That is, in step S10, it is determined whether the movement value [ZN+1] of the increment memory is the number of "15" pulses or the number of "16" pulses, and when the number of pulses is "15" or "16", the actual value is determined in step 811. , the number of output pulses of the rotary encoder RE is counted, and the movement value [M] of the correction memory that stores the counted value up to the next position is set to "4". Similarly, in step 812, the movement value [ZN+11] of the increment memory is set to "10 to 14".
Determine the number of pulses, and when the number of pulses is "10 to 14",
In step 813, the number of output pulses of the rotary encoder RE is actually counted, and the movement value [M] of the correction memory, which stores the counted value up to the next position, is set to "2". Similarly, in step 814, it is determined that the movement value of the increment memory = 14-[ZN+11 is the number of pulses "5 to 9", and the value is set to "5".
~9'' pulse number, the movement value [M] of the correction memory is set to ``1'' in step 315. Further, in step 816, the movement value [ZN+1
] is the number of pulses "4" or less, and if it is the number of pulses "4" or less, the movement value [M] of the correction memory is set to "0" in step S17.

In step S10, step S12, step S14, and step 816, the movement value [ZN+
1] is not equal to or less than "16" pulse number, the correction memory movement value [M] is determined in step S18.
is set to "ZN+1-15". In addition, the movement value of the increment memory [ZN+11]
15'' is the average value of overrun in the constant speed driving state and the constant speed driving approximate state when the high speed setting valve SV is closed.

In step S19, it is determined that the movement value [M] of the collection memory is the number of M26J26J pulses, and when the movement value [M] of the collection memory is greater than or equal to the number of N26J pulses, the moving object 6
In order to shorten the moving time, the high speed setting valve SV is opened in step S20 to speed up the rotation of the moving shaft formed by the ball screw 3. When the movement value [M] of the correction memory is less than the number of r126J pulses, the high-speed setting valve S■ is closed in step S21, and the air motor AM, which causes a predetermined overrun state, is brought into rotation. and,
At step 322, for each output pulse of the rotary encoder RE, "1" is subtracted from the value of the movement value [M] of the correction memory that stores the count value up to the next position.
The value is set as the updated value of the movement value [M] of the collection memory. The routine from step S19 to step 823 is repeatedly executed until the movement value [M] of the correction memory becomes "0" in step S23. In step 823, when it is determined that the correction memory is moved (direct [M] (direct) has become rOJ, step S
21! ! Then, the solenoid 11 that was energized to perform forward rotation in step S7 or the solenoid 11R that was energized to perform reverse rotation in step S9 is de-energized, the air motor valve BV is closed, and the air motor AM is set to a stopped state. do. Then, in step 825, the air brake AB is brought into a braking state by the air brake valve BV. Then, the process exits from the motor subroutine j and executes the main program process according to the normal control program.

The braking device for the air motor according to the above embodiment of the present invention uses the reading means for reading the current position coordinates, and reads the count value of the moving counter with the home position as "0" from the output of the rotary encoder RE. [X]
get. Then, the movement target coordinate [Y] reading means reads the movement target coordinate [Y] of the next position from the memory whose address is the position given by teaching.

[Y co - [xN co]ON+1 is calculated by the air motor rotation direction determining means which is determined from the current position coordinate [X] and the moving target coordinate [Y], and whether the value is positive or negative is determined. Then, a count value [Z] for driving the air motor AM is obtained by a drive counting means that obtains a count value [Z] for driving the air motor AM calculated from the current position dust 1 [X] and the movement target coordinate [Y].
In order to set [Z] in the incremental memory, [Z] = [YN+1] - [XN] according to the rotation direction.
Or, calculate as [Z]=[X]-[YN+11to1N.

Furthermore, a braking correction means that corrects the count value [2] obtained by the drive counting means using the braking characteristics of the air motor AM to obtain a correction count value [M] corresponds to the overrun amount.
The correction count value [M] is set in the correction memory, and the braking timing is obtained based on the correction count value [M] set.

The count value [Z] obtained by the drive counting means of this embodiment is corrected by the braking characteristics of the air motor AM, and the corrected count value [M
] is given by the pulse number/overrun characteristic diagram shown in FIG.

In the figure, the number of pulses of rotary encoder RE is "16".
'', the amount of overrun in terms of the number of pulses is approximately constant at the number of pulses ``15''. In this embodiment, the number of pulses "16" or less of the rotary encoder RE is divided into four groups, and a correction count value [M] obtained from the characteristic value is set for each group. In addition, in step S16, it is determined whether the movement value [ZN+1] of the increment memory is less than or equal to the number of "4" pulses, and when it is less than or equal to the number of pulses "4", the movement value [M] of the correction memory is set to "O" in step S16. " is set to mean that the error of the apparatus of this embodiment will not be less than "4" in terms of the number of pulses of the rotary encoder RE.

In addition, when carrying out the present invention, it is divided into four groups as in the above embodiment, and each group is given a correction count value [M] obtained from the characteristic value.
The overrun amount is not limited to the means for setting, and as can be judged from the characteristic diagram in FIG. 6, the overrun amount can be approximately selected from the number of moving pulses. The corrected count value [M] can be recalled from the memory by storing the address in the memory for each number of moving pulses. However, in this case, there will be errors in the amount of overrun due to environmental changes such as temperature, aging changes such as wear of component parts, dirtiness of lubricating oil, etc., so the number of memories will be considerable. However, no improvement in accuracy can be expected. As in the above embodiment, it is effective to divide into a plurality of groups and set a correction count value [M] obtained from the characteristic value to each of the divided groups.

Further, in this embodiment, explanation has been made on the assumption that the moving body 6 attached to the moving shaft consisting of the ball screw 3 shown in FIG. The moving axis consisting of 3 can also be used as the moving side. Or, the ball screw 3 attached to the arm
The arm can also be moved by a movement axis consisting of.

= 20- In any case, it can also be used for control equipment such as robots as a moving means for moving in two-dimensional or three-dimensional space.

[Effects of the Invention] As described above, the air motor braking device of the present invention has a means for reading the current position coordinate [X] and a means for reading the moving target coordinate [X].
reading means for reading the current position coordinate [X] and the moving target coordinate [Y]; and means for determining the rotational direction of the air motor based on the current position coordinate [X] and the moving target coordinate [Y]; The count value that drives the air motor to be calculated [Z
], and a drive counting means for correcting the count value obtained by the drive counting means using the braking characteristics of the air motor to obtain a corrected count value [
M], and a braking means that operates an air brake with the correction count value [M] obtained by the brake correction means, and the moving target coordinate specified by the move command at each position. It calculates the moving distance from the current position coordinate [x] by referring to the value of [Y], and also obtains the timing for braking the air motor using a correction count value that matches the braking characteristics of the air motor. Therefore, the current error can be corrected for each position before moving to the next position, and the previous error will not be accumulated for repeated move commands, so the braking of the air motor Accuracy can be increased.

In addition, since anticipatory braking is performed according to the braking characteristics of the air brake, there is no need for high-speed control, and it can be handled using a counter or memory, so a microcomputer is used to control the equipment that uses the air motor. If the microcomputer has a built-in counter or memory, you can use the microcomputer's built-in counter or memory. therefore,
Braking accuracy can be improved without adding more parts.

[Brief explanation of drawings]

Fig. 1 is an overall circuit configuration diagram of an air motor braking device according to an embodiment of the present invention, Fig. 2 is a front view of the main parts with a partial cross section of the driving part and braking part of the position setting system, and Fig. The circuit diagrams of the pneumatic circuit of the position setting system shown in the embodiment of FIGS. 1 and 2, and the "motor subroutine" for driving the air motor of the air motor braking device of the embodiment of the present invention are shown in FIGS. FIG. 6 is a pulse number/overrun characteristic diagram. In the figure, RE... rotary encoder, BF... photo-electric conversion circuit, CPU... microcomputer, AB... air brake, AM... air motor. In addition, in the figures, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A means for reading the current position coordinate [X], a means for reading the movement target coordinate [Y], and a means for determining the rotational direction of the air motor based on the current position coordinate [X] and the movement target coordinate [Y]. and drive counting means for obtaining a count value [Z] for driving the air motor calculated from the current position coordinate [X] and movement target coordinate [Y]; an air motor comprising: a braking correction means for correcting the braking characteristics to obtain a correction count value [M]; and a braking means for operating an air brake with the correction count value [M] obtained by the braking correction means. Braking device. (2) The braking correction means groups the count values obtained by the drive counting means into a predetermined number of groups, and corrects each group based on the braking characteristics of the air motor. Air motor braking device.