JPS59224291A - Industrial robot - 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 The present invention relates to an improvement of an industrial robot, and particularly to a play bank type robot whose position can be controlled manually via an operation panel, which facilitates teaching operations.

Industrial robots such as those described above are well known.

The mechanical configuration of the robot is configured according to various purposes, such as rectangular coordinates, cylindrical coordinates, and multiple joints. However, when performing manual position control via the operation panel, the control means of the control device includes control axes based on rectangular coordinates in addition to these mechanically configured control axes, making manual operation easier. Recently, flooring is being implemented (for example, Japanese Patent Application Laid-Open No. 57-1398'' No. 10 @
).

In a robot configured in this way, the end effector is controlled manually by the operator, and the end effector is controlled by a rectangular coordinate control system. For example, when a welding torch is used as an end effector, the distance between the torch and the workpiece is kept constant, and the position of the torch is controlled to the position of the welding point by moving the torch forward and backward. Unless the axial direction coincides with the control axis direction of the Cartesian coordinate control system, a plurality of axes must be controlled simultaneously, and this operation is not easy.

Therefore, the present invention attempts to solve the above-mentioned problem by providing an industrial robot that can be manually controlled in a direction perpendicular to a workpiece fixed to an end effector while maintaining a constant distance from the workpiece in a specific direction. It is something.

The outline of the present invention is to provide a play bank type industrial robot in which the relative positions of an end effector and a workpiece can be manually controlled via a control panel in a manual mode of a control device. A distance sensor with respect to the workpiece surface in a specific direction of a local rectangular coordinate system is fixedly provided on the end effector or is provided in place of the sensor, and a distance sensor with respect to the work surface in a specific direction of the local coordinate system is provided on the control panel. The industrial robot further comprises an operating means for controlling the position of the end effector, and the control device includes means for making the distance between the distance sensor and the workpiece constant during position control by the operating means. be.

An embodiment of this invention will be described in detail below with reference to the drawings. Although this example is an articulated robot that uses a welding torch as an end effector, the invention is not limited to this embodiment.

Reference numeral 1 denotes an industrial robot, and in this embodiment, it is an articulated robot having five rotational degrees of freedom α□ to α6 as shown. The robot 1 is equipped with MIG welders 1 to 2 as end effectors. 3 is a conduit tube that guides the consumable electrode TW of the torch 2.

4 is a known welding power supply device. The device 4 includes a spool 4a for winding up the consumable electrode TW of the torch 2, and a spool 4a that takes up the consumable electrode TW of the torch 2.
A welding power source 4b is connected and suspended between W and the workpiece WK.

Reference numeral 5 denotes a known computer as a main part of the control device of this embodiment. Computer 5 includes a CPU and memory.

The pass line BK of the computer 5 is connected to the power supply 4b.

The pass line BK is further connected to a servo system Sα1 for the α1 axis of the robot. The servo system Sα includes a power Mα0 for the α1 axis and an encoder Eα1 that outputs its position information. Also connected to the pass line B are an α2-axis servo system Sα2, an α3-axis servo system Sα3, an α4-axis servo system Sα4, and an α5-axis servo system Sα6, which are configured in the same manner.

RE is a remote control panel that forms part of the control device and serves as a control panel, and is provided with a group of manual operation snap switches SW. Then, by tilting the stem of the snap switch for each of the X, Y, Z, Φ, and θ control axes (cartesian coordinate axes for control, fixed to the base 1a of the robot 1) from the neutral position shown in the figure toward the Uj side, the control The end effector is configured to move in the opposite direction when tilted toward the rDJ side in the direction in which the positional information of the axis increases.The Φ and θ control axes each control the turning angle and attitude angle relative to the orthogonal coordinate axes. These configurations require an algorithm for coordinate transformation by the computer 5 between the multi-joint system of the mechanism and the rectangular coordinate system of the control.However, the details are well known and will not be described in detail.

The operation panel REK is also provided with a speed command rotary inch SV in auto mode. In addition, a mode changeover switch SM is provided, including manual 7 mode 1-M and test mode T.
E and auto mode A. SE is a selection switch. By switching upward in the figure and operating the up/down switch SU, the welding condition number W is displayed and selected. Furthermore, move this switch SE to the left as shown,
The mode is selected and displayed as either linear interpolation "L" or circular interpolation rCJ by operating the switch SU. Furthermore, the operation panel REK is provided with a start switch ST. The function of the switch ST will be explained in detail in the explanation of the operation described later.

Furthermore, the operation panel RE is provided with various switches, which are the characteristics of the configuration of this invention. Let's discuss it in detail below.

First, there is a sensing mode setting switch SS, and the sensing mode can be set by turning this switch SS from OFF (as shown) to ON and setting the sensing distance (described later).

A manually operated snump switch group SWT in sensing mode is provided, which has the same configuration as the Ushida switch group SW. The switch SWT has local orthogonal control axes Tx and T with respect to the Tx axis in the direction of the axis T of the torch 2 as shown.
, y direction, the torch 2 is configured as a switch to be manually operated.

Each of these switches is also connected to pass line B.

Furthermore, the sensor SN having a configuration unique to this invention will be described.

The torch 2 is assumed to have a distal end 2b of a base 2a which can be attached and detached by, for example, screw means. And the tip part 2
Remove a and attach the separately prepared sensor SN. The details of one embodiment of this sensor SN are as shown in FIG. 2, and the base end of the main body 6 can be attached to and detached from the tip of the base 2a of the torch 2 with a screw 6a. The tip of the main body 6 is the stylus 6
b is fitted so that it can move forward and backward, and is biased forward (downward in the figure) by a spring 6C. A linear potentiometer 6d is provided at the base of the stylus 6b, and outputs analog information regarding the movement of the stylus 6b. When installing the sensor SN, it is assumed that when the protrusion length of the stylus 6b is 4, the tip of the stylus 6b matches the operation of the torch 2, ξP, etc. Furthermore, the direction of the axis T of the torch 2 is the local coordinate TZ fixed to the torch 2 as described above, and the two directions orthogonal thereto and mutually orthogonal are the local coordinate TZ.
Let it be X and T7.

As shown in the figure, the workpiece WK is to be welded along a horizontal corner welding line WL from point P to P2 on this welding line WL.

For this purpose, first, teaching of the user program is executed. In the following description, please also refer to FIG.

The operator instantly operates the switch SM to set the manual mode. Normally, when one of the switches SW is operated, the computer 5 reads each switch on the operation panel RE (processing PR1), and the position and orientation of the torch 2 is controlled along the X-system control axis (processing PR8 to PR ，
). First, the operating point P in front of the torch 2 is located at the point PX, and its posture (Euler angle, that is, Φ and θ)
shall be determined as appropriate. In this case, if the torch 2 is taught at a position too close to the workpiece W, the protrusion length of the consumable electrode TW during welding (so-called extension length) becomes short, and the welding current becomes excessive. On the other hand, if the torch 2 is taught at a position that is too far away from the workpiece W, the welding current during welding will be too small, and the welding result will be unsatisfactory. Therefore, the operator must pay close attention to the positioning of the torch 2 in the longitudinal axis T direction. In that case, it will be understood that it is difficult to operate only the switch SW.

Therefore, in this embodiment of the invention, the operator first operates the switch SS to turn it on, enters the sensing mode, and sets the dimension l.

The Surt computer 5 processes this in a judgmental manner (PR,),
First, the position of TZ is controlled so that the dimension of sensor SN becomes l (processing PR,).

If we put this into the formula, Tz=K (0-f(L))
becomes. Here, f (L) is the quantity detected by sensor SN, and I( is a constant).

That is, depending on whether the output of the sensor SN is smaller than the value corresponding to the set dimension β, if it is a dog, the torch 2 is moved forward in the Tz direction (toward the point P), and if it is small, the torch 2 is moved in the opposite direction. . That is, the computer 5 adjusts each control axis α so that the output of the sensor/sensor SN has a value corresponding to the set dimension l.
, to α6. Also, when the operator operates the switch SWT, the computer 5 reads this information (processing PR□ and PR,) and controls the position of the torch 2 in the TX direction or Ty force direction while keeping the set dimension l constant as described above. do.

In other words, if the current position information is X, the time (interval time for issuing commands) Δ and the subsequent position command information is x", then ΔTx, ΔTy, and ΔTZ are the torch 2
are the distances to be moved in the force direction of the axes Tx, 'T'y, and Tz. Also, M is the coordinate system Tx, Ty, T
The conversion matrix from Z to the absolute coordinate system X is IJ.

At this time, if the switches Φ and θ of the switches SW are operated without operating the switch SWT, -n+' -n - This is the amount of change in the absolute coordinate system X.

In this way, Yn+1 is calculated and determined (processing PR6), and the coordinates are transformed from the value of ``>(n+'') to obtain the command value 7 for each mechanical control axis α or α6 (processing PR4
). The details of this coordinate transformation from X to 7 can be found in Japanese Patent Publication No. 4
Since it is well known from Publication No. 9-50376, etc., it will not be described in detail.

Then, these command values α are output (processing PR,).

Further, with the passage of time Δt (processing Pit), it is difficult to judge whether the user program for control is final or not.
, ), otherwise the process returns to process PR.

In addition to the above-mentioned embodiments, this invention can also be modified as described below.

(a) When the sensor SN is of a contact type as in this embodiment, the output means may be other means than a potentiometer, such as a differential transformer. Furthermore, the sensor SN may be of a non-contact type, such as a known electromagnetic type or an optical type.

(b) The sensor SN is installed as in the previous embodiment.
Rather than attaching or replacing the end effector, for example, it is installed symmetrically with the end effector with respect to the a5 axis, and the end effector and sensor can be selected by rotating the a6 axis. A known configuration may be used.

B) The end effector may be a known cutting torch, a holder, a painting gun, etc. in addition to a welding torch.

(e) It is also possible to replace it with an equivalent item composed by another person.

As described above, the present invention has the following unique and remarkable effects.

■ In a playbank type robot, the end effector is equipped with a distance sensor from the work surface in one direction of a fixed local coordinate system, and this distance is kept constant, making it possible to manually control the position along the local coordinate system. Therefore, manual position control for teaching can be easily performed. This is especially important for the X, Y, and Z axes, and for the workpiece W.
It will be understood that this is particularly noticeable when the direction of the work line WL of K does not match the direction of the work line WL.

CB) 'The configuration is simple, and if you use a computer or a computer for the control device in addition to the sensor, you can easily add software.
JTl implementation example

[Brief explanation of drawings]

The drawings all show one embodiment of this invention, with FIG. 1 being an overall perspective view and block diagram, and FIG. 2 being a partially enlarged vertical sectional view.
FIG. 3 is a flowchart. 1...-Industrial robot, 2... Welding torch (end effector), 5... Computer (control device),
W K, Work, RE, Control panel, Tx,
Ty, TZ... Local rectangular coordinate system, SN... Distance sensor, SWT... Switch (operating means), PR6.
...Processing (means to make the distance constant). Applicant ShinMaywa Industries Co., Ltd.

Claims (1)

[Scope of Claims] (1) In a play bank type industrial robot in which the relative positions of an end effector and a workpiece can be manually controlled via a control panel in a manual mode of a control device, the end effector is A distance sensor with respect to the work surface in a specific direction of a fixed local rectangular coordinate system is fixed to the end effector or provided in place of the sensor, and a distance sensor with respect to the work surface in a specific direction of a fixed local rectangular coordinate system is provided on the control panel. The industrial apparatus further comprises an operating means for controlling the position of the end effector in a direction of , and the control device includes means for keeping the distance between the distance sensor and the workpiece constant during position control by the operating means. robot. (2) The industrial robot according to claim 1, wherein the end effector is a welding torch, and the specific direction is an axial direction of the torch. (2) The industrial robot according to claim 1, wherein the end effector is a cutting torch, and the specific direction is an axial direction of the torch. (4) The industrial robot according to claim 1, wherein the control device is mainly a computer.