JPS60195614A - Robot teaching system - Google Patents

Abstract

PURPOSE:To easily teach a robot at optional places without receiving any restrictions, by performing the teaching operation by realizing the same operating locus as the spatial operating locus of a means which designates one point in a space with a multidegree of freedom manipulator. CONSTITUTION:A position/direction input device 110 sends the coordinates of the hand of a teacher to a reference coordinate system and the rotating angle of the hand from the reference coordinate system to a moving quantity determining device 120. The device 120 calculates the moved and rotated quantities of the hand by comparing the sent data of coordinate and rotating angle with those of one hour before and sends the calculated result to a controlling quantity determining device 130. The device 130 finds the joint angle controlling quantity of the robot from the sent moved and rotated quantities and a model of robot mechanism and sends the found quantity to a communication device 140. The device 140 sends commands to rotate each joint by inputted joint angle controlling quantities to a robot controller.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a robot manipulator, and particularly to a teaching method suitable for teaching motion to a robot manipulator.

[Background of the invention]

Conventionally, movements have been taught to robot manipulators mainly using the following three methods.

(1) Teaching box teaching Necessary movements are taught by combining several basic commands prepared in advance.These basic commands are
It is usually given by pressing a key on a teaching box connected to the controller of the robot manipulator. Figure 1 (A) shows an example of a teaching box.
Shown below. FIG. 1(B) shows an example of the functions (command contents) of each person's oyster 14. In FIG. 1(A), 11 is a hook, 12 is an on/off slide switch, and 13 is a display light emitting diode.

Although this teaching box method is used for teaching many robot manipulators, it has the following fundamental flaws.

■ It takes a lot of effort (number of key presses) to teach complex movements, and it takes time to teach them.

■ It takes time to get used to the teaching method because there is a weak relationship between the teaching action of teaching and pressing a key.

■ Teaching boxes are commonly made for robots of the same model, but when actually teaching a certain robot, the operator must use the teaching box to compensate for individual differences between robots. No.

(2) The direct teaching operator directly touches the robot manipulator (
In this method, the required movements are taught (by holding the tip of a robot manipulator).

This method has the following flaws.

■ Robot manipulators cannot be used in locations that are difficult for operators to access (for example, in narrow spaces or under high radiation).

■ A heavy robot manipulator places a heavy burden on the operator.

(3) This is a method in which a masked slave type teaching operator performs teaching using an operation handle that has the same structure as the robot manipulator that is the object of teaching and is connected to the robot manipulator through a communication line.

This method allows the operator to freely control the state of the robot manipulator without being aware of the rotation angle of each degree of freedom of the robot manipulator. C
Therefore, the operation by the operator is very easy.

The drawback of this method is that separate operating handles must be provided for each (different) robot. Tsumashi,
Problems arise in terms of cost and space.

[Purpose of the invention]

The present invention is intended to solve the above-mentioned problems of the conventional system, and when the operator traces and teaches the (complex) movements that the robot manipulator should perform by himself/herself, the operator does not need to use special equipment or the robot manipulator. The purpose is to provide a teaching method based on a teaching software joystick that does not have restrictions such as contact and can be easily performed at any location.

[Summary of the invention]

In order to achieve the above object, the teaching method according to the present invention is characterized by performing the following two-step process.

+1) By introducing a means to measure the position of the joystick in space online, the operator can trace the movement trajectory he or she wants to teach by holding this joystick, and the movement trajectory he or she wants to teach can be traced to the point of interest of the robot manipulator V-Yu. Input as a continuous point sequence of coordinates.

(2) The input motion locus is converted into a control input using a mechanical model of the robot manipulator that is the object of teaching.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2 to 7. FIG. 2 shows the configuration of an embodiment for realizing the present invention.

In the second factor, the position/direction input device 110 inputs the coordinates (x+Y+7) of the teacher's hand relative to the reference coordinate system and the rotation angle (θ, ψ, φ) from the reference coordinate system to the movement amount determining device 110.
Send to 0. The movement amount determination device 120 calculates the amount of movement and rotation of the instructor's hand by comparing the sent data (coordinates per rotation angle) with data from one time ago, and uses this result as the control amount determination device. Send to 130. The control amount determination device 130 determines the joint angle control fif of the robot based on the received movement/rotation amount and robot mechanical model, and sends it to the communication device 14.
Send to 0. The communication device 140 sends a command to the robot controller to rotate each joint by a joint angle control amount.

FIG. 3 shows the configuration of the position/direction input device wt110. The joystick 111 consists of a digitizer input pen 114, a rack ball 113, and a switch 115. The coordinate detection board 112 has four ultrasonic transmitters embedded therein. Joystick (ultrasonic receiver) 111
and coordinate detection board 112 are connected to controller 116. When the switch 115 is turned on, the controller 116 activates the four ultrasonic transmitters of the coordinate detection board 112, and at the same time receives input from the digitizer input ben 114 and determines the coordinate position (xlYl z) of the digitizer input ben 114. 'Calculate to '.

When the switch 115 is turned on, the trackball 113 sends the rotation angle (θ, ψ, φ,) of the three-axis rotation of the robot manipulator from its reference position to the controller 116. While the switch 115 is on, the controller 116 determines the position coordinates and the rotation angle using a movement amount determination device +112.
Send to 0.

A three-dimensional digitizer that combines a digitizer input ben 114, a coordinate detection board 112, and a controller 116 is already commercially available. In addition, a commercially available system can be used to input the amount of rotation using a trackball.

FIG. 4 shows how to use the joystick 111. Now, move the end effector 151 of the robot 150 to the current position A.
Let's say you want to move from point B to point B via bus AB. At this time, the operator turns on the switch 115 of the joystick 111 at an arbitrary position A' on the coordinate detection board 112, and while looking at the end effector 151, "as if he was holding the end effector 151".
Move the joystick 111 from point A' to point B't. At point B, when the direction of the end effector 151 needs to be corrected, the trackball 113 is rotated in the correction direction by the amount required for correction.

FIG. 5 shows a configuration diagram of the movement amount determining device 120.

The coordinate/rotation angle data sent from the position/direction input device 110 is temporarily stored in the position register 121.

The clock 123 sends a signal to the movement amount calculating device 122 at fixed time intervals (hereinafter referred to as tsec). When the movement amount calculating device 122 receives the signal from the clock 123, it calculates the coordinate/rotation angle data of the position register 121 (mar Y + '+
7j+, 9' r <' ) and save register 1
Coordinate/rotation angle data t seconds ago stored in 24 (xlY
l zl θ, ψ, φ) as follows,
Movement amount (ΔX, Δy.

Δ2. Δ0. Δψ, Δφ) is −C, which is determined by the judgment device 1.
Send to 25.

ΔX =
1 coordinate/rotation angle data (rl Y I F+1, c
p, #) are stored in the save register 124.

(By this operation, the data in the save register 124 is saved by 1). "+'j"+r), and if the absolute values of all elements of the coordinate/rotation angle data vector are smaller than the elements of the maximum value data vector,
The coordinate/rotation angle data vector is sent to the control device 130. The maximum value data vector is a vector of the maximum value that can be achieved in seconds (for example, X is the maximum amount of movement in the X-axis direction for t seconds). FIG. .

The angle register 131 stores the robot's joint angles (α, α2, α3° C4, C5, C) obtained through the communication device 140.
6). When the robot movement amount is sent from the movement amount determination device 120, the starter 134 sends a signal to the position calculation device 1:32 and at the same time sends the robot movement amount to the destination calculation device 135. The position calculation device 132 is
Upon receiving a signal from the starter 134, the angle register 13
Read the current joint angles of the robot from Memory 1 and use the mechanical equations of the robot read from Memory 1 to determine the current position (xlYl2) of the robot end effector and the coordinate system O.
Calculate. Here, the robot is 6
The mechanical equations for the four axis robots are as follows.

X = C+ (C234+C23a3+C2az I
Y=St (Czs4+Cua3+Cza21"=S
234 a 4 +S2! la3+s2 C2 Here, On the other hand, the coordinate system 0 is the absolute coordinate system (the base of the robot...
(point F in Figure 7 is the origin) is described by the following formula.

To = AT The destination calculation device 135 calculates the robot movement amount (ΔX, Δy, Δ2.Δθ, Δψ) obtained from the starter 134.

Δφ), the robot end effector position obtained from the position calculation device 132, and the coordinate system O, the new position of the robot end effector (xN+:l'N+zH) and the coordinate system ON are determined by the following equation.

xH = Ma + ΔX yN = De + Δy Z N = z + Δ2 The destination calculation device 135 calculates the calculated new position (XN, YNI Z) J) of the robot end effector and the new coordinate system O
N to the angle calculation device 136.

The angle calculation device F136 is a memo! Using the inverse representation of the mechanical equation stored in JB 137 (the mechanical equation mentioned earlier is an equation with the input and output variables reversed), from the new position of the end effector and the new coordinate system ON, Calculate each joint angle of the robot. In the case of the 6-axis robot shown in FIG. 7, the joint angle (α,

α2. α3. α4. α5. α6) is determined by the following formula.

R+ = C23a3+C2a2 几2°523a3+52a2 "4" tan -' s----α2-α3CIa
X+Sla.

q = -Ca (0234 (C + O engineering + 8102) +
82340□) In the above equation, the following expression is used as the new coordinate system ON.

Note that the equation for calculating αl−α6 above includes trigonometric functions, and generally a plurality of α1 to α6 are obtained as solutions. For example, however, the (b) rotation angle Δα that the robot manipulator is capable of during t(m) is less than a certain value εα. Therefore, the α that can be claimed must satisfy the constraint that α − ε times α and α16 compared to α one time ago. The angle calculation device 136 reads each joint angle of the robot manipulator from the angle register 131, and determines each joint angle target value αl to α6 based on the above constraints.

In Fig. 7, 71 indicates the shoulder, 72 indicates the nirbow, 73 indicates the wrist, and 74 indicates the hand.

〔Effect of the invention〕

As detailed above, according to the present invention, (1) the same effect as conventional direct teaching can be obtained without touching the robot manipulator, so teaching can be performed even when it is difficult for the operator to approach the robot manipulator;

(2) Since the motion locus is input as an analog quantity, teaching can be performed more easily than in the conventional teaching box method. (For example, in a conventional teaching pendant,
When moving the robot manipulator from point (1, 1, 1) to point (5, 6, 7), move J14 for each axis, that is, first move from (1, 1, 1) to (5, 1, 1). and then from (5, i, i) to (5, 6, 1). Even those with the function of moving in 2 or 3 axis directions at 1b'' were very limited (for example, 45 directions for each axis) and were rare.

In contrast, the teaching according to the invention allows movement in any direction.

(3) Unlike master-slave type robots, special equipment is not required. By changing the mechanical model of the target robot manipulator, it can be applied to all types of robot manipulators, so even in places where many types of robot manipulators are introduced, only one teaching device is required, which reduces costs. .

[Brief explanation of the drawing]

Figure 1 shows an example of a teaching box, Figure 2 shows an example of a teaching box.
3 shows an example of the configuration of the position/direction input device shown in FIG. 2. FIG. 4 shows an example of the use of the position/direction input device. Fig. 5 shows an example of the configuration of the movement amount determining device shown in Fig. 2, Fig. 6 shows an example of the configuration of the control amount determining device shown in Fig. 2, and Fig. 7 shows an example of a robot manipulator. . χ 4121 City 5 Eup/30 No. 6 (2)/40

Claims (1)

[Claims] means for specifying one point in space; and means for measuring the position of the point in space specified by the device for specifying one point in space;
means for storing a mechanical model of a multi-degree-of-freedom disk manipulator and the multi-degree-of-freedom manipulator; a means for determining control variables of the multi-degree-of-freedom manipulator based on the mechanical model; A robot teaching system comprising a communication means connecting the control variable determining means, in which a multi-degree-of-freedom manipulator is used to realize a motion trajectory identical to the motion trajectory in the space of the means for specifying a point in the space. A robot teaching method characterized by teaching a degree of freedom manipulator.