JPS6322955B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive control device for a robot equipped with a telescopic actuation arm. Hereinafter, in this specification, robots include loaders, manipulators,
The term is used to include automatic machines such as conveyors, automatic processing machines, and all kinds of cargo handling equipment.

Conventionally, robots with telescoping operating arms have been equipped with balance weights at the base of the arms to maintain a balanced state of operation, in case the robots operate while holding a relatively heavy load, work tool, etc. at the tip of the arm. Generally, the structure is such that it maintains the following.

Recently, a ram, which is a fluid cylinder, has been used as the balance weight to perform balance drive control corresponding to loads such as conveyed loads, but in this control, the positioning accuracy of the ram is low. The desired positioning of the arm tip was performed exclusively manually by the operator. In other words, in a telescopic arm robot using a ram, automatic positioning and speed control of the tip of the arm have not been conventionally performed.

The present invention has basically been made in view of the above points, and is configured to improve the above-mentioned type of robot so that positioning can be automated and speed controlled. Neutral zone (dead zone) in the working arm drive system that exists as a
This paper proposes a robot drive control device that is compatible with That is, the present invention
A ram and a motor are linked together as a driving source for the vertical movement of the actuating arm, and the vertical load due to the actuating arm's own weight, including the load of working parts such as mounting jigs, and the conveyed load is handled by the driving force of the ram and motor. The vertical movement control of the actuating arm is divided into two parts, and a device capable of converting the pressing force of the ram is also provided.

The present invention will be described below based on an embodiment shown in the drawings.

FIG. 1 is a front view showing a robot embodying the present invention. This robot A operates by urging a telescoping operating arm 1 on the robot body 2 side, and also attaches the robot body 2 to a robot support 3. The working arm 4 is configured to pivot relative to the working arm 1, thereby allowing the working end portion 4 of the actuating arm 1 to move within a three-dimensional range. In the embodiment shown in FIG. 1, the robot A is used as a conveyor for holding and conveying a load 5 in a working section 4.

The control device of the present invention incorporated in the robot A is configured to control the operation of the arm 1 during the extension and contraction operations of the operating arm 1.
The driving source is a ram R having a pressing force F _R conversion device 6, and a variable driving force F _M linked to this ram R. A motor M for output is provided.

As shown in FIG. 2, the operating arm 1 is composed of a first link 7, a second link 8, and auxiliary rods 9, 9 attached parallel to one of these links 7, 8, respectively. The tip working portion 4 performs a lifting operation by vertically moving the arm base 10, and a traversing operation by laterally moving the connecting portion 11 of the auxiliary rods 9,9.

The ram R is pressed downward in FIG. 2 with a pressing force F _R set by the pressing force conversion device 6, and this pressing force F _R
2, the set value is always maintained regardless of the vertical position of the ram piston 13.

Further, the motor M is connected to a control device (not shown), and outputs an arbitrarily variable driving force F _M to the actuating arm 1 under output control of the control device.

By the way, the pressing force conversion device 6 is operated by the central control unit B.
As shown in FIG. 3, a pressure regulating valve 61 and a solenoid valve 62 form a three-parallel circuit. , a relief valve 63 and a check valve 64 are interposed between the electromagnetic valves 62c. Secondary pressure Pa of each pressure regulating valve 61a, 61b, 61c,
Pb and Pc correspond to the three locations in the neutral zone (dead zone) D shown in FIG. Pressure regulating valves 61a, 61b, 6
The secondary pressures Pa, Pb, Pc of 1c are applied to the actuating arm 1.
For the driving force corresponding to the moment due to the resultant force of the vertical load due to its own weight and the load W, the first circuit is
The second circuit absorbs the static frictional force in the actuating arm drive system when the actuating arm 1 starts moving upward, the second circuit deals with the kinetic frictional force in the actuating arm drive system at least during the movement of the actuating arm 1, and the third circuit deals with the static frictional force in the actuating arm drive system when the actuating arm 1 starts moving upward. The static friction force in the actuating arm drive system during the downward movement of No. 1 is set to a pressure value that is balanced with the applied driving force. Note that the secondary pressure Pb of the circuit is preferably set to a value that also exceeds the dynamic friction during driving of the actuating arm 1. Further, the relief valve 63 controls the pressure so that the secondary pressure in the circuit becomes (=Pc). In addition, as mentioned above, the solenoid valves 62a,
62b and 62c are operated in response to a command from the central control unit B, and the circuits 62b and 62c are thereby individually brought into conduction.

As shown in FIG. 2, the actuating arm 1 is linked with the motor M by fixing the arm base 10 to a rack 15 that meshes with the pinion 14 of the motor M, and the rack 15 is connected to a set pressing force. The ram R that presses downward with F _R is the rack 15.
are linked through. Also, ram R and motor M
The ram R is always connected to Rack 1 with a predetermined force.
Since 5 is pressed, a mere contact connection is sufficient. The base 10 of the actuating arm 1 is engaged with a vertical guide 16 provided on the robot body 2 so as to be able to move up and down. That is, the vertical guide 16 is provided to absorb external forces applied to the rack 15, pinion 14, etc. Reference numeral 17 denotes a position detector composed of a linear potentiometer or the like, which detects the vertical position of the arm base 10.

FIG. 5 shows another embodiment of the connection between the motor M and the arm base 10, and shows a protrusion 1 provided on the arm base 10.
A cable body 19 is fixed to the upper and lower ends of the cable 8, and the cable body 19 is pulled in the vertical direction by a motor M, thereby variably driving the motor M. Alternatively, the ram R and the arm base 10 may be directly linked and the base 10 may be pulled from below.

Note that the configuration of the ram R and motor M described above and the linkage between these and the arm base 10 are not limited to the embodiments shown in FIGS. Any mechanism may be used as long as the driving force of the ram R is energized and the variable driving force of the motor M can be transmitted.

In this example of the above structure, the dead weight of the actuating arm 1 including the load of the working part 4 such as the mounting jig (hereinafter simply referred to as the dead weight of the actuating arm 1) is an upward vertical load on the arm base 10. Acts as Wc,
Further, when a load 5 is held as shown in FIG. 1, the load W acts on the arm base 10 as an upward vertical load Wx similar to the arm 1's own weight. To explain in more detail, the load Wc due to the dead weight of the operating arm 1 is determined by the specifications of the robot A, and is approximately constant even when the arm end working section 4 is in traverse operation, so it appears as a constant value load. In addition, the above load Wx is a value (W・L ₂ /L 1 ) obtained by multiplying the load W of the load 5 by the ratio of the distances L ₁ and L ₂ shown in Fig. 2 (W・L 2 /L ₁ ), which is also a constant value load and can be easily used during robot operation. can be revealed. A pressing force F _R corresponding to this load (Wc+Wx) is set by the conversion device 6, and the load is shared by the ram R. On the other hand, the motor M controls the vertical movement of the operating arm 1, which is in a balanced state due to the operation of the ram R.

The drive control described above differs depending on the vertical movement direction of the arm tip working section 4. That is, when moving upward, the electromagnetic valve 62a is opened to conduct the circuit, and pressure Pa is applied to the ram R to eliminate the effects of static friction and the like as much as possible. As a result, motor M
The driving force F _M may be small, therefore,
Not only can the motor M be small, but the mechanism such as a rack and pinion connected to the motor M can also be extremely simple and small enough to carry out the present invention.

Once the actuating arm 1 is actuated, the influence of static friction disappears, so the circuit is closed and conductive, and a pressure Pb, which is smaller than the pressure Pa but takes into account dynamic friction, is applied to the ram R. . Thereby, the above-mentioned equilibrium state between the load (Wc+Wx) and the ram pressing force F _R can be better realized.

Next, when the arm end working part 4 is to be lowered, the solenoid valve 62c of the circuit is closed and the pressure is reduced.
The PC is powered up. At this time, the pressure difference between the pressure Pc caused by the previous pressure Pb or pressure Pa is canceled by the relief valve 63, and the secondary pressure of the circuit can be maintained equal to the pressure Pc, and therefore, Driving force F _M required by motor M to start descending
may be small as above. Once the actuating arm 1 is actuated, the circuit is closed and conductive as described above, and the pressure Pb is applied to the ram R.

As explained above, the present invention provides a ram having a pushing force conversion device and a motor in conjunction with each other as a vertical movement drive source for a telescopic actuating arm of a robot, and further reduces the vertical load due to the actuating arm's own weight and conveyance load. Since the structure is such that the vertical movement of the operating arm is controlled by the motor and the vertical movement of the operating arm is controlled by the ram, arm control can be performed while minimizing the vertical load applied to the motor. In addition to being able to carry loads (weight), automation of robots with high positioning accuracy can be easily realized. Furthermore,
The linkage mechanism between the motor and the actuating arm only needs to have a structure strong enough to withstand the small power of the motor driving force, and the mechanism can be simplified and miniaturized in response to the miniaturization of the motor. , the robot drive mechanism itself can be downsized.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a robot implementing the present invention, Fig. 2 is a block diagram showing a mechanism according to the present invention, Fig. 3 is a block diagram showing a pushing force converting device, and Fig. 4 is a diagram showing the ram pushing force. FIG. 5, which shows the neutral zone, is another embodiment of the linkage mechanism for transmitting driving force. A...Robot, 1...Operating arm, 2...Robot main body, 3...Robot support, 4...Tip working part, 5...Load, 6...Pushing force conversion device, 61...
...Pressure regulating valve, 62...Solenoid valve, 63...Relief valve, 64...Check valve, 10...Arm base, 1
2...Pressure source, M...Motor, R...Ram (cylinder), Wc...Arm load, Wx...Transfer load,
W...Load, F _M ...Motor driving force, F _R ...Ram pressing force, _L1 , _L2 ...Distance, B...Central control unit,
D... Neutral zone, P (Pa, Pb, Pc)... Secondary pressure,
,,……circuit.

Claims (1)

[Claims] 1. Used in a robot that controls the vertical movement of the operating arm by sharing the vertical load due to the weight of the telescopic operating arm and the conveyed load with the pressing force of the cylinder and the variable driving force of the motor. A pressing force converting device comprising three parallel circuits, each comprising three pressure regulating valves and a solenoid valve, is connected to the cylinder, and is equipped with a pressure source and a control section, and the pressing force converting device is connected to the cylinder. In each circuit, the secondary pressure of each pressure regulating valve is converted into a driving force corresponding to the moment due to the resultant force of the vertical load due to the dead weight of the actuating arm and the conveyed load, and the first circuit is configured to start the upward movement of the actuating arm. The second circuit absorbs the static friction force in the actuating arm drive system during at least the movement of the actuating arm, and the third circuit deals with the kinetic friction force in the actuating arm drive system at least when the actuating arm is moving downward. The static friction force in the arm drive system is set to a pressure value that balances the applied driving force, and the pressures of the pressure regulating valves with different secondary pressures are controlled via the solenoid valves by commands from the control section. A drive control device for a robot, characterized in that the cylinder is energized.