JPS6049101A - Pneumatic actuator control system - Google Patents

Abstract

PURPOSE:To improve preciseness to stop a member driven by a pneumatic actuator to a home position by supplying air pressure to both side ports of the actuator alternately when the driven member approaches the home position to make it reach the home position. CONSTITUTION:When the invention is applied to an arm driving actuator 13 of a pneumatic robot, two supply and discharge ports of the actuator 13 connected with solenoid-controlled transfer valves 19, 20 respectively are arranged to be selectively connectable to the atmosphere through variable throttle valves 23, 24 and silencers 25, 26, or to a pneumatic source through a pressure control valve 21 by using a common air line. When the arm reaches to a set point P1 at a certain distance from a target position P2 each solenoid-controlled valve 19 and 20 is alternately turned to ON and OFF, and the time intervals of the ON and OFF T1, T2... become shorter with the approach of the arm to the target position P2. By this control, the arm is stopped precisely at the target position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for a pneumatic actuator used in a pneumatically driven robot or the like.

With drive systems that use pneumatic actuators, it is extremely difficult to accurately stop the actuator at an intermediate position between both ends of its stroke due to the compressibility of air.
Currently, it is hardly used in high-end Roboso I. The present invention is aimed at solving these problems, and is capable of stopping a driven member (robot arm, etc.) driven by a pneumatic actuator in a fixed position with high precision, and 1-1. The present invention provides a control method that speeds up the total cycle time and allows efficient work to be performed.

The following will be explained based on illustrative drawings. In FIGS. In this rotary table, 4 is a first γ-arm connecting the rotary table 2 and the intermediate members 5 and ′, and 6 is a second arm connecting the intermediate member 5 and the tip member 7.The first arm 4 is 0; 1 rear pair of parallel swing links 5a, 5
b, which moves the intermediate member 5 in the backward direction with respect to the rotary table 2 while holding it in a constant posture, and the nearer parts 1 and 6 are a pair of upper and lower parallel swing links 9a.
, 9b, which allows the distal end member 7 to be moved in the vertical direction relative to the intermediate member 5 while maintaining a constant posture. Although not shown, the robot hand is attached to the tip member 7 via a suitable actuator. 10
is a pneumatic actuator which rotates the rotary table 2 within a predetermined range with respect to the base 1; C1 is attached to the base 1; Reference numeral 11 denotes a first arm drive pneumatic actuator attached to the rotary table 2, which swings the link 8a within a predetermined range via a drive shaft 12 on the rotary table 2 side.

16 is a pneumatic actuator for driving the first arm attached to the middle 11J1 member 5, and is a link? b is swung within a predetermined range via the drive shafts 14 of five intermediate members. Further, 15 is a pneumatically operated γ actuator for the balancer that acts on the nearer side, and is attached to the intermediate member 5 on the opposite side to the side where the first arm drive pneumatically operated actuator (6) is located. and urges the link ?b of the 6iJth position upward via the 6iJth drive shaft 14.

16 is a pulse encoder that is interlocked with the rotation of the rotary table 20. Reference numeral 17 denotes a pulse encoder that moves as the first arm 4 swings, and is operatively connected to the 0:1 link drive shaft 12. Reference numeral 18 denotes a pulse encoder that is interlocked with the rocking motion of the near-total rotation, and is interlocked with the link drive shaft 14 .

According to the above-mentioned pneumatically driven robot robot 1-, each actuator 10. Arm 4
The robot hand attached to the tip member 7 is preset by causing the tip member 7 to perform a predetermined movement consisting of a combination of forward and backward rocking of , and vertical rocking of the nearer end relative to the intermediate member 5 . The control system of the present invention will be explained in detail next.

Figure 3 shows the pneumatic actuator 1 for driving the first arm.
In the figure, 19.20 is an electromagnetic switching valve, 21 is a pressure regulating valve, 22 is a check valve, and 25.
24 is a variable throttle valve, 25° and 26 are 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 inside the actuator 1'5 flows out via the throttle valve 24). By making it possible),
Pressure 13]? Pneumatic pressure adjusted to a constant pressure by the J valve 21 is supplied to the normal rotation drive side boat of the actuator 16,
The actuator 15 rotates in the normal rotation direction, and the nearer rotation moves upward. When the near position reaches the set position P1 at a certain distance n:1 from the target position P2, the electromagnetic switching valve 19 is turned off as shown in FIG.
FF, the electromagnetic switching valve 20 is reversed to the ON state, a predetermined pneumatic pressure is supplied to the reverse drive side boat of the actuator 1 for an appropriate time t, and a braking force is applied to the actuator 15, and then the 71 magnetic switching valve 19.20
Returns the ON/OFF state. This operation is performed at fTIi constant time intervals Tl, T2 . It is repeated at T3..., but as it approaches the target position P2, l
i: 1 time interval Tl, T2. ．． T3... is advanced one by one. As a result, the motion speed (2) of the near-deflector driven by the actuator 16 is rapidly and smoothly decelerated after passing through the set position P1, as shown in FIG. When the nearer deviation reaches the target value @P2, both the electromagnetic switching valves 19 and 20 are turned on (by supplying the same air pressure to both boats of the actuator 15, the nearer Braking means (not shown) for locking the nearer unevenness to the intermediate member 5 in a state B in which the unevenness is positioned at the target position P2 so as not to rotate.
Activate and fix the second nearer at the set position. When moving the 1st nearer side down, use the solenoid switching valve 19.
．． 20 in the reverse order to the above and rotate the actuator 1'5 in the opposite direction. The other actuators, the pneumatically actuated actuator 10 for driving the rotary table and the pneumatically actuated actuator 11 for driving the first arm, are also driven by the same control system as the actuator 15 (they are similarly pneumatically driven and moved to the set position). The rotary table 2 and the first arm 4 that have arrived are fixed by the brake means as described above.

The pulse signals of each of the pulse encoders 16 to 18 are used by a conventionally known method to detect the current positions of the rotary table 2, the first arm 4, and the second near rotor, and the detected current position values are set as set values. As shown in the above embodiments, the electromagnetic switching valve 19.20 and the electromagnetic switching valve used in the pneumatic control system of the other actuators 10.11 are switched when The control method of the pressure-actuated robot is such that after the driven members driven by the pneumatic actuator (in the embodiment, the rotary table 2, the first arm 4, and the nearer arm) approach the target position,
pneumatic pressure is supplied to both boats of the actuator alternately, and the pneumatic supply boat switching tact is accelerated as the boat approaches the target position, o: 1. The driven member is decelerated while reaching the target position. This feature makes it possible to make the rising speed of the driven member sufficiently large at the initial stage of operation, and to rapidly and smoothly decelerate the driven member from just before the target position, thereby allowing the driven member to reach the target position.゛C1 The total cycle time from the start of movement of the driven member until it reaches the target position can be greatly shortened, and the driven member can quickly and accurately reach the target position without pulsating. Since stability can be reduced, for example, by applying the present invention to the drive system of a pneumatically driven robot, it is possible to achieve highly accurate control that cannot be achieved with conventional pneumatically operated robots.

[Brief explanation of drawings]

Figure 1 is a side view showing the entire robot, Figure 2 is a rear view of the same, Figure 3 is an explanatory diagram showing part of the control system in the pneumatic actuator, and Figure 4 is an explanation of the control of the electromagnetic switching valve. FIG. 5 is a diagram illustrating the speed change in the process of the robot arm reaching the target position.

Claims (1)

[Claims] After the driven member driven by the pneumatic actuator approaches the target position, pneumatic pressure is applied alternately to both boats of the 0:I actuator, and as the driven member approaches the target position, the pneumatic supply boat switching tact is accelerated. A control method for a pneumatically actuated actuator, characterized in that the driven member is slowed down while reaching a target position.