JPS60241502A - Control system of pneumatically operated actuator - Google Patents

Abstract

PURPOSE:To improve the accuracy of a position of stopping a driven member by throttling an exhaust path of a pressure operated actuator when the driven member approaches a target position. CONSTITUTION:An electromagnetic change-over valve 22 and a throttle valve 29 are interposed in an exhaust path of a pneumatically operated actuator 15 for a balancer. When a driven member 6 approaches a target position, the electromagnetic change-over valve 22 is changed over to throttle the exhaust path of said actuator 15. Thus, a large resistance is given to the motion of the driven member 6 so that the driven member 6 can be braked quickly and smoothly. Hence, the accuracy of a position of stopping the driven member 6 can be improved.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to various industrial robots, particularly a pneumatic actuator for a balancer that provides a balance moment to a driven member, or a pneumatic actuator for driving the driven member. Can be used for industrial robots equipped with actuators.
This invention relates to a control method for pneumatic actuators.

(Prior art and its problems) Pneumatic robots that use pneumatic actuators as described above can be implemented at a much lower cost than robots that use electric motors, but they do not require highly accurate position control. Due to the difficulty, it has not been put into practical use. In particular, when stopping a driven member driven by a pneumatic actuator at a predetermined intermediate position, when the driven member reaches just before the stop position, the pneumatic supply boat in the actuator is switched and the driven member is temporarily directed in the opposite direction. Control has been considered in which a driving force is applied to rapidly brake the driven member, and finally, pneumatic pressure is supplied to both pneumatic supply ports of the actuator to stop the driven member.
Even with such control, it is difficult to smoothly and quickly reach a predetermined stop position without causing the driven member to vibrate. The present invention aims to solve these problems.

(Means for Solving the Problems) That is, the control system of the present invention provides an exhaust path of a pneumatically actuated actuator for a balancer that provides a balance moment to the driven member when the driven member approaches the target position, or the driven member This system is characterized by narrowing the exhaust passage of the pneumatically actuated drive actuator and applying braking to the driven member.

(Example) An example of the present invention will be described below based on the attached illustrative drawings.

In Figures 1 and 2, 1 is the base, 2 is the base 1
a rotary table rotatably supported on the top about a vertical axis 3;
4 is 11tt before connecting the rotary table 2 and the intermediate member 5.
! A movable arm 6 is a vertically swinging arm that connects the intermediate member 5 and the tip member 7.

The longitudinal swinging arm 4 has a pair of front and rear parallel swinging links 8a.
, 8b, which allows the intermediate member 5 to be moved in the front-rear direction with respect to the rotary table 2 while maintaining a constant posture.

The vertically swinging arm 6 has a pair of upper and lower parallel swinging links 9a.
, 9b, which allows the distal end member 7 to be moved vertically relative to the intermediate member 5 while keeping its posture constant. Although not shown, the robot hand is attached to the tip member 7 via a suitable actuator. 10
is a pneumatic actuator that rotates the rotary table 2 within a predetermined range with respect to the base 1, and is attached to the base 1. Reference numeral 11 denotes a pneumatic actuator for driving the front and rear swinging arms attached to the rotary table 2, which swings the link 8a within a predetermined range via the drive shaft 12 of the two rotary tables. Reference numeral 13 denotes a pneumatic actuator for driving the vertically swinging arm attached to the intermediate member 5, which swings the link 9b within a predetermined range via the drive shaft 14 of the five intermediate members. Further, 15 is a pneumatically actuated actuator for a balancer that acts on the vertically swinging arm 6, and is a pneumatically operated actuator for driving the vertically swinging arm.
The link 9b of the vertically swinging arm 6 is connected to the drive shaft 14
is biased upward through the 16 is a pulse encoder that is linked to the rotation of the rotary table 2. A pulse encoder 17 is linked to the swinging of the longitudinal swinging arm 4, and is linked to the link drive shaft 12. A pulse encoder 18 is linked to the swinging of the vertical swinging arm 6, and is linked to the link drive shaft 14.

According to the above-mentioned pneumatically controlled robot, each actuator 10, 11, 13 is pneumatically actuated to rotate the rotary table 2 with respect to the base 1, to swing the longitudinal swing arm 4 with respect to the rotary table 2, and to By causing the tip member 7 to perform a predetermined movement consisting of a combination of nine vertical swings of the vertically swinging arm 6 relative to the intermediate member 5, the robot hand attached to the tip member 7 is moved along a preset movement trajectory. The desired work can be performed automatically. On the other hand, the pneumatic actuator 15 for the balancer is supplied with pressurized air whose pressure is adjusted to correspond to the change in the downward moment acting on the vertical swinging arm 6, so that the upward balance moment is applied to the vertical swinging arm 6. Grant.

Next, in FIG. 3, which specifically explains the control system of the actuator 13.15 based on FIGS. 3 to 5, 19 to 22 are electromagnetic switching valves, 23 to 25 are pressure regulating valves, 26 are is a check valve, 27-29 is a variable throttle valve, 30-3
2 is a silencer. According to this pneumatic control system, the electromagnetic switching valve 19 is turned on (a state in which air pressure is supplied to the actuator 13), and the electromagnetic switching valve 20 is turned off (air can flow out from inside the actuator 13 via the throttle valve 28). state), air pressure adjusted to a constant pressure by the pressure regulating valve 23 is supplied to the normal rotation drive side port of the actuator 13, the actuator 13 rotates in the normal rotation direction, and the vertical swing arm 6 is rotated. It will move up.

As shown in FIGS. 4 and 5, the vertical swing arm 6 is moved to a set position P a certain distance before the target position 1iP3.
1, the electromagnetic switching valve 19 is turned OFF, the electromagnetic switching valve 20 is turned ON, and after an appropriate period of time, air pressure of a predetermined pressure is supplied to the boat on the reverse drive side of the actuator 13 to control the actuator 13. After applying power, 'r!' again! Return the ON and OFF states of LVA switch t[19 and 20 to their original state. This operation is performed at predetermined time intervals T1, T2 . This is repeated at T3..., and as the target position P3 approaches, the time intervals Tl, T2, . T3... is advanced one by one. As a result, the upward motion speed V of the vertically swinging arm 6 driven by the actuator 13 is rapidly decelerated after passing the set position P1.

On the other hand, the air pressure regulated by the pressure regulating valve 23 is
By switching the electromagnetic switching valve 21, the pressure regulating valve 24.
25 to the balancer pneumatic actuator 15, which imparts an upward balance moment to the vertically swinging arm 6. Switching of the electromagnetic switching valve 21 is performed according to the angle of the vertical swinging arm 6, and when the angle with respect to the horizontal plane is within a certain range, the high pressure regulated by the pressure regulating valve 24 is applied to the actuator 1.
5, a large balance moment is applied to the vertical swing arm 6, and when the angle of the upper and lower tSS farms with respect to the horizontal plane exceeds a certain range, low pressure regulated by the pressure regulating valve 25 is supplied to the actuator 15, and the vertical swing arm 6 The electromagnetic switching valve 21 is automatically switched so that the balance moment applied to the swing arm 6 is reduced.

In this state where the balance moment is applied by the pneumatic actuator 15 for balancer, when the vertical swinging arm 6 is moved upward by the drive actuator 13, the exhaust gas is pushed out from the boat on the atmosphere-opening side of the actuator 15. Ha,'T! i. As long as the magnetic switching valve 22 is in the OFF state, the air flows through the exhaust path that does not pass through the throttle valve 29, so there is no special resistance. However, in the process in which the vertically swinging arm 6 reaches the target position P3 from the set value iP, by turning on the electromagnetic switching valve 22 when it reaches the set value WP2 set immediately before the target position P3, Said actuator-1
The exhaust gas pushed out from the boat on the atmosphere-opening side of No. 5 passes through the exhaust path passing through the throttle valve 29, and is therefore met with great resistance.

Therefore, a braking force is applied to the vertically swinging arm 6, and the vertically swinging arm 6 is moved to the target position P3 as shown in FIG.
The speed is further rapidly decelerated at the immediately previous set position P2.

When the vertically swinging arm 6 reaches the target position P3 in this way, both the electromagnetic switching valves 19 and 20 are turned ON, and the same air pressure is supplied to both boats of the actuator 13, so that the vertically swinging arm 6 Move arm 6 to target position P
3, a brake means (not shown) for locking the vertically swinging arm 6 against the intermediate member 5 so as not to swing is activated, thereby fixing the vertically swinging arm 6 at the set position.

To move the vertically swinging arm 6 downward, the electromagnetic switching valves 19 and 20 may be switched in the reverse order to the above, and the actuator 13 may be rotated in the opposite direction. In this case, the balancer pneumatic actuator 15 operates in the same manner to apply an upward balance moment to the vertically swinging arm 6, but since outside air is sucked into the actuator 15 through the boat on the atmosphere-opening side, As described above, when the electromagnetic switching valve 22 is turned ON at the set position P2, the intake air is resisted by the throttle valve 29, and as a result, it moves downward.''A braking force is applied to the lower swing arm 6. Forced to slow down.

Note that when the vertical swing arm 6 is moving downward, exhaust from the actuator 15 is performed from the pressure regulating valve 2425, so the exhaust boat of the pressure regulating valve 24.25 is also equipped with an exhaust passage equipped with a throttle valve. An open exhaust path is connected via an electromagnetic switching valve that operates at the same time as the electromagnetic switching valve 22, and from one actuator 15 after the vertically swinging arm 6 that is moving downward reaches the set value WP2. The braking effect can be enhanced by passing the exhaust gas through the throttle valve as in the case of upward movement.

The operation timing of each of the electromagnetic switching valves 19 to 22 is determined by a comparison calculation between the current position (swing angle) of the vertical swinging arm 6 detected using the pulse encoder 18 and a set target position. However, since the swinging speed of the vertically swinging arm 6 can be detected from the amount of swinging of the vertically swinging arm 6 per unit time using the pulse encoder 18, if the swinging speed is fast, the activation timing can be brought forward. The electromagnetic switching valves 19, 20 . It is desirable to automatically adjust the operating timing of and 22.

Other actuators, that is, the pneumatically actuated actuator 10 for driving the rotary table and the pneumatically actuated actuator 11 for driving the front and rear swinging arms, are similarly pneumatically driven by the same control system as the actuator 13, and the rotary table reaches the target position. 2 and the longitudinal swing arm 4 are fixed by the brake means as described above. In addition, when a pneumatic actuator for a balancer is used, which biases the longitudinal swinging arm 4 into a vertically standing position, the longitudinal swinging arm 4 is The method of the present invention can also be implemented for.

In the above embodiment, the system of the present invention was implemented using a pneumatically operated actuator for a balancer, but it is also possible to implement the system of the present invention without using a pneumatically operated actuator for a balancer. For example, in the pneumatic control system shown in FIG. 3, instead of interposing the electromagnetic switching valve 22 and the throttle valve 29 in the exhaust path of the pneumatically actuated actuator 15 for the balancer, The electromagnetic switching valve 22 and the throttle valve 29 are respectively interposed between the throttle valve 27, 28 of the exhaust passage connected to the boat via the electromagnetic switching valve 19, 20 and the muffler 30, 31,
It is also possible to operate the electromagnetic switching valve 22 in the same manner as in the embodiment described above. Furthermore, the electromagnetic switching valve 22
Instead of adding the throttle valve 29 separately, the throttle valve 2
It is also possible to achieve the desired purpose by automatically changing the aperture ratio of 7.28 at a predetermined time.

(Operations and Effects of the Invention) According to the control method of the pneumatic actuator of the present invention as in the above embodiment, when the driven member (the vertically swinging arm 6 in the embodiment) approaches the target position, the driven member This is an extremely simple method that simply narrows down the exhaust path of the pneumatic actuator for the balancer that provides a balance moment, or the exhaust path of the pneumatic actuator for driving that drives the driven member, and can be implemented at a very low cost. Although it is a method, it is possible to provide a large resistance to the movement of the driven member by restricting the exhaust passage and brake the driven member quickly and smoothly, and to improve the accuracy of the stopping position of the driven member, the aim is to use a pneumatic actuator for driving. Even if the driven member is operated alternately in forward and reverse directions before the position, by using the method of the present invention in combination, the driven member will not vibrate before stopping, and it can be stopped at a predetermined target position with high precision without vibration. . As a result, there is no need to reduce the driving speed of the driven part y itself, and it is possible to drive the driven part y at high speed until it approaches the target position, thereby shortening the cycle time and improving the overall work efficiency.

[Brief explanation of the drawing]

Figure 1 is a side view, Figure 2 is a rear view with the lower part of the base omitted,
Figure 3 is an explanatory diagram showing the pneumatic control system of the vertically swinging arm, Figure 4 is a diagram explaining the control of the electromagnetic switching valve, and Figure 5 is the speed of the vertically swinging arm in the process of reaching the target position. It is a figure explaining a change. DESCRIPTION OF SYMBOLS 1... Base, 2... Rotating table, 4... Front-rear swing arm, 5... Intermediate member, 6... Vertical swing arm, 7...
...Tip member, +0.11.13...Pneumatic actuator, 15...Pneumatic actuator for balancer, 19-22...Solenoid switching valve, 23-2
5...Pressure adjustment valve, 27-29...Variable throttle valve, 3
0-32...silencer.

Claims (1)

[Claims] When the driven member approaches the target position, the exhaust path of the balancer pneumatic actuator that provides a balance moment to the driven member or the exhaust path of the driving pneumatic actuator that drives the driven member is throttled, and the driven member is A control method for pneumatic actuators that applies braking.