JPS63278104A - Robot controller - Google Patents

Abstract

PURPOSE:To shorten the arithmetic processing time of position data by forwardly transforming position data of each selected lattice point in advance to data of a robot working coordinate system which is an orthogonal coordinate system and storing this data in a buffer memory or the like. CONSTITUTION:Point data is set at each lattice point in accordance with the position of a hand and the mode of attitude control in a robot controller consisting of a CPU 1, a ROM 2, a RAM 3, a servo control circuit 6, etc. When linear movement between two points is commanded by point data, a proper mark is added to a memory area, and data is transferred to a buffer memory when this mark is read at the time of palletizing, and data is read out from the buffer memory. Data requiring forward transformation is preliminarily stored as table data in the buffer memory, and data used for locus control is stored in each joint buffer or the like without being reversely transformed. Thus, the forward transformation and reverse transformation processings are unnecessary at the time of controlling the position and the attitude of the robot hand to shorten the operation processing time of position data.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a robot control device that shortens the calculation processing time of position data during palletizing execution.

(Prior Art) In recent years, various types of robots have been used in various industrial fields such as manufacturing and distribution to streamline operations. For example, there is an increasing demand for robot control devices having a palletizing function that instructs a robot to perform palletizing (depalletizing) for stacking and unloading workpieces.

When palletizing workpieces at multiple predetermined positions, it is necessary to define the palletizing positions in advance, but by defining the representative point of the palletizing point and the approach pattern, the representative point of the defined palletizing point can be Specify the combination of and approach pattern,
Palletizing work may be performed by robots.

FIG. 4 is an explanatory diagram of an example of such teaching of palletizing points. In this example, the palletizing point is
Qll, Q21. ..., teach Qj21゜QLI,
Also, a point C11M in the height direction is taught.

FIGS. 5(a) and 5(b) are explanatory diagrams showing examples of approach pattern teaching. FIG. 5(a) shows the approach pattern for the bottom point Q11, and the starting point S
The robot hand moves along the route Po'Pi Qll-Po'-end point R.

Moreover, FIG. 5(b) is an explanatory diagram of the approach pattern n to the bottom point Qllx, and the starting point 5-Po
-pl-Qj21-p2-p3-A motion pattern passing through the route of end point R is shown.

Next, the palletizing operation when the palletizing points and approach patterns are defined as shown in FIGS. 4, 5(a) and 5(b) will be explained. Now, if the palletizing point (lattice point) is Q42m, QuIQJ2 m-((m-
1)/(M-, 1)) Qly Ql 1 is calculated. Then, the pattern n is shifted so that the lattice point Qum becomes the bottom point.

The positional information of each grid point obtained in this way is stored in a link buffer of a memory (not shown), and when the robot is operated, the data stored in this link buffer is read out and predetermined control is performed. .

(Problems to be Solved by the Invention) In such palletizing processing, multiple types of approach patterns are set for each point Q iJk shown in FIG. Robot joint data such as bottom point and approach pattern are stored in each memory area as command pulse values for each axis. When execution of the palletizing function is actually commanded, the command pulse values for each axis are converted into the robot's working coordinate system, for example, the orthogonal coordinate system, and the memory areas [A2] and [B21]
...is stored in... As a result, necessary point data is formed from the instructed grid points, and the position and orientation of the hand in the work coordinate system are determined as coordinate values that match the target position and orientation. Next, the coordinate values of the work coordinate system (orthogonal coordinate system) are inversely converted into each axis command pulse value, and the robot hand is driven.

The processes necessary to execute such a palletizing function are performed in the following order.

(1) Perform preprocessing necessary for selecting grid points, etc.

(2) Calculate the position and orientation of the grid points.

(3) Shift the approach pattern to match the grid points.

(4) Reverse convert each point data and set it in the link buffer.

(5) Actual robot motion control is performed according to the data in the link buffer.

Conventional calculation processing of position data when executing such a palletizing function involves first reading out each data set in the bubble memory, sequentially converting reference points such as the bottom point, R, and P, and then converting the approach pattern. The command pulse values for each axis are obtained by performing forward conversion processing on the passing points included in the image, and performing inverse conversion processing on each shifted point of the finally determined approach pattern.

Therefore, although it is essential for robots introduced to reduce takt time on automobile assembly lines to shorten the time required for palletizing work, conventional robots are unable to perform forward and reverse conversion processes. It was taking up a lot of time.

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a robot control device that can shorten the calculation processing time of position data.

(Means for Solving the Problems) The present invention provides a robot control device having a palletizing function that causes a robot hand to stack or unload workpieces at multiple locations determined based on taught data. a first storage means for storing each axis command pulse value of the robot at an operating point as forward transformation data based on the robot working coordinate system; and a first storage means for storing the command pulse value of each axis of the robot at an operating point as forward transformation data, and data necessary for control at an operating point where trajectory control is executed as forward transformation data. a second storage means for storing a processing code at each operating point; a third storage means for storing a processing code at each operating point;
, and control means for controlling the position and posture of the robot hand at each operating point based on the forward transformation data stored in the second storage means.

(Function) According to the robot control device of the present invention, position data for each selected grid point is converted in advance into data in a robot work coordinate system of an orthogonal coordinate system and stored in a buffer memory or the like, When the command code of each grid point is read, the forward conversion data in the buffer memory can be used to control the position and posture of the robot hand.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

Figure 2 shows an example of a robot configured for six-axis control: θ-axis, W-axis, U-axis, α-axis, β-axis, and γ-axis.
It is connected to a robot control device that has a palletizing function that performs unloading, and grips workpieces with hands to perform predetermined palletizing.

FIG. 1 is a block diagram showing a schematic configuration of a robot control device to which the present invention is applied. As shown in the figure, this robot control device uses a CPU with a built-in register array.
and memory ROM2. RAM3, input/output boat l104
, a power board 5, and a servo control circuit 6 are connected by an address/data bus 7. The servo control circuit 6 has a position amplifier, a speed amplifier, and a current amplifier, and includes a current detector 9 using a current transformer CT of a servo motor 8 that drives each axis, and a speed detector 10 using a tachogenerator TG. , a current loop, a speed loop, and a position loop are formed using each detection value of the position detector 11 using the pulse coder PC, and predetermined control of the servo motor is performed.

A servo motor is provided for each control axis, in this case, five servo motors are provided for driving each axis of the robot, and each servo motor is equipped with a servo control circuit 6 connected to an address/data bus. .

FIGS. 3(a) and 3(b) are explanatory diagrams showing an example of control in the above embodiment.

゛ Figure 3 (a) shows the area of the memory that stores the point data of each grid point, and the G code GIJ etc. is set for each grid point according to the hand position and posture control mode. (1 and J are any numbers from 0 to 9).

For example, when commanding linear movement between two points using a GOI code, an appropriate mark, such as *, is assigned to this memory area.

When this mark * is read at the time of execution of palletizing, the data is transferred to the buffer memory shown in FIG. 6(b) and read from there. The buffer memory contains the x, y, and z coordinate values obtained by converting the command pulse values of each axis into the Cartesian coordinate system that is the work coordinate system of the robot, and the hand posture vector (
L, M, N) are stored in the robot control device that controls the robot hand.
Predetermined position and attitude control can be performed without performing inverse conversion calculations. That is, in the case of trajectory control, especially linear control, both the forward conversion operation of the teaching data and the inverse conversion operation regarding the division points, which require particularly processing time, are omitted, so the processing time is significantly shortened.

In addition, the data for each grid point calculated by shifting from the bottom point and approach pattern can also be stored in a predetermined area as a data table of the orthogonal coordinate system in the buffer memory shown in FIG. , when the robot hand moves to each grid point, there is no need to calculate the command pulse value of each axis by forward conversion operation in the CPU, and the robot control data can be directly output from the buffer memory and instantaneously applied to the next workpiece. You can move on to action.

In addition, like movement between reference points P and R and grid points,
If the G code requires an inverse transformation operation, it is necessary to perform the inverse transformation operation on the point data formed by the forward transformation operation.

In this way, the conventional palletizing function converts each axis command pulse value into orthogonal coordinate values of the position and posture of the robot hand, and performs many inverse conversion operations for other palletizing positions calculated from the teaching point. Taking note of the fact that the processing time is long due to the calculation steps required, the aim is to omit unnecessary conversion operations as much as possible. That is, (1) data that requires forward conversion is stored in advance in a buffer memory as table data, and (2) data used for trajectory control is stored in each joint buffer without being inversely converted.

This eliminates the need for forward and reverse conversion processing when controlling the position and posture of the robot hand, which reduces palletizing time and is beneficial in reducing the takt time of assembly robots introduced to line work.

Although one embodiment of the present invention has been described above, various different embodiments can be easily constructed without departing from the spirit of the present invention. The present invention is not limited to the embodiments.

(Effects of the Invention) As explained above, the present invention can significantly shorten the time required for inverse and forward conversion operations of data used for trajectory control during palletizing execution, reduce palletizing processing time, and reduce calculation results. It is possible to provide a robot control device that can reduce the load on the CPU during execution according to the capacity of the area that stores the robot.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a robot control device applied to the present invention, FIG. 2 is an overview diagram showing an example of a robot controlled by the device of the present invention, and FIGS. 3(a) and (b) are FIGS. 4 to 6, which are explanatory diagrams showing examples of operation patterns in the present invention, are diagrams for explaining normal palletizing operations. 1...CPU, 2...ROM, 3...RAM, 4
...110.5...Power electrical panel, 6...Servo control circuit, 7...Address/data bus, 8...Servo motor, 9...Current transformer, 10...Speed detection Vessel, 11.
...Position detector.

Claims (1)

[Claims] In a robot control device having a palletizing function that causes a robot hand to stack or unload workpieces at multiple locations determined based on taught data,
A first storage means for storing each axis command pulse value of the robot at a specific operating point as forward conversion data using the robot working coordinate system, and a first storage means for storing the data necessary for control at the operating point where trajectory control is executed. a second storage means for storing data as data; a third storage means for storing a processing code at each operating point; and a forward transformation stored in the first and second storage means when the processing code is read. 1. A robot control device comprising: control means for controlling the position and posture of a robot hand at each operating point based on data.