JPS6227802A - Hand control device for industrial robot and its control method - Google Patents

Abstract

PURPOSE:To control the locus of movement or the posture of a tool highly accurately by setting up the leading end of the tool as a reference point for coordinate conversion to control a hand. CONSTITUTION:A manual sending command is applied from a teaching operation panel 54 to the hand to make the center point of a tool fitting surface of the hand coincide with the leading end 15a of a setting jig 15. At that time, the displacement data of respective axes are fed back and stored in a memory 53 as base data. Then, a prescribed tool is fitted to the hand and the leading end of the tool is made to coincide with the leading end 15a of the jig 15 again on the basis of the manual sending command. The displacement data of respective axes obtained at that time are compared with the base data and reference point data to be the reference of coordinate conversion are operated by a control part 51. Thereafter, the postures of the axes are changed, the leading end of the tool is made to coincide with the fixed point plural times and the reference point data are rewritten every coincidence. At the completion of the reference point data, the setting jig 15 is removed, the position, speed and working command of the tool are taught and a hand control command is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides an industrial robot whose hand is precisely controlled by setting a reference point, which is a reference point for coordinate transformation of the industrial robot, at the tool tip. The present invention relates to a hand control device and a control method.

(Prior Art) Recently, robots have become widespread and are being used in many fields. Under these circumstances, robots are increasingly required to have highly accurate and reliable performance.

In particular, articulated robots have many operating axes and can perform tasks with a high level of accuracy in controlling the position and posture of their hands, so they are often used in welding operations and the like. FIG. 5 is a perspective view of such a five-axis industrial robot.

In the diagram, BS is a base installed on the factory floor, etc.
A θ-axis drive mechanism 1 for driving the θ-axis is provided at the top. 2 is a W-axis drive mechanism, and 3 is a W-axis arm driven by the W-axis drive mechanism 2. 4 is a U-axis arm, which is driven by a U-axis drive mechanism 5 via a U-axis sink 6. 7
is the wrist of the robot, and a hand 7a is provided at the tip of the wrist, and this hand 7a is equipped with a tool (worker 3A) such as a welding torch.
) 8 has been repeated. In addition, 9 is the α-axis drive mechanism, 10
is the β-axis drive mechanism. The wrist 7, hand 7a and tool 8 are shown enlarged in FIG.

(Problems to be Solved by the Invention) As shown in FIG. 6, the hand posture vector in the hand coordinate system is Q, +m, m, and.

The basic axes of the tool coordinate system are tL, u, and v. Note that oh indicates the origin of the hand coordinate system, and TCP indicates the tool center point.Although the robot remembers its own reference coordinate system and hand coordinate system, it cannot set the position of the tool 8 attached to the hand 7a. It was difficult to do.

In other words, in order for the robot to grasp the relationship between the hand coordinate system and the tool coordinate system, it must perform complex coordinate transformation calculations in small calculation cycles to determine the hand position from the displacement of each degree of freedom. However, there is a problem in that the deviation from the taught point cannot be reduced. In particular, there are a wide variety of tools 8 attached to the hand 7a, and the positions that should be set for each are different, making it extremely difficult to accurately control the movement trajectory and tool posture based on work commands. there were.

An object of the present invention is to provide a hand control device and control method for an industrial robot that can accurately control the movement trajectory and tool posture by controlling the hand using the tool tip as a reference point for coordinate transformation. do.

(Means for Solving the Problems) The present invention is an industrial robot that controls the position and orientation of a tool attached to a robot hand while aligning each axis of the robot with a target value. - In the hand control device, means for storing the displacement of each axis as base data when the center point of the tool mounting surface of the robot hand coincides with a predetermined point of the robot reference coordinate system; A means for setting a fixed point such that a plurality of axis postures can be changed and matched with respect to a point fixed in coordinates, and coordinate conversion by comparing each axis displacement when matching with the fixed point with the base data. and means for determining the target position of each axis of the robot based on the data regarding the tool position and orientation,
The hand is configured to be controlled using the tip of the tool as a reference point for coordinate transformation in accordance with a predetermined work command by the tool.

(Function) According to the present invention, setting of tool coordinates, which was conventionally complicated, can be easily and accurately performed using a simple method, and the practical effects are great.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram illustrating the configuration of a hand control device for an industrial robot according to the present invention.

In the figure, the pace data storage unit 11 is a memory such as a RAM connected to a CPU with a microprocessor configuration.
When the center point of the tool mounting surface of the robot hand 7a is aligned with a predetermined point of the robot reference coordinate system (x, y, 2), for example, the origin O, the displacement of each axis is stored as base data. 8 with respect to a point fixed to the robot reference coordinates, for example, a point (X,, 0.O) on the X axis,
A fixed point is set so that multiple axis postures can be changed and matched, the data is stored in the storage unit 12, and the robot is moved by manual feed by operating the manual feed button on the teaching operation panel. This fixed point and the tip of the tool 8 are made to coincide, and the displacement of each axis at that time is stored in the storage section 12.

Generally, articulated robots have many degrees of freedom in order to move smoothly according to movement commands, so the displacement of each axis is not determined in one way for the same hand position, and the movement of each axis is limited. Even in consideration, there are multiple manual feeding methods described above. Therefore, the axis posture is changed to align the tool tip with the fixed point, and when the tool tip matches the fixed point, the displacement of each axis is compared with the base data to perform coordinate transformation (stored in the recording section 13 as focusing data). can be done.

In this way, the tool tip is used as the reference point for coordinate transformation, and the calculation unit 1
By inversely converting each axis target position in step 4, each axis control command with less error can be determined.

Figure 2 shows that during teaching, Ropontono! An example of a setting jig fixed to a half surface is shown.

This setting jig 15 has a tip 15a that is a robot, j,
It is used to set the fixed point of the Ii'sA coordinate system, has dimensions known to the robot, and is removably fixed to the reference plane 16 of the base, where the origin O of the robot) and quasi-coordinates is set. be done. Therefore, with this tip 15a as a predetermined point, the center point of the tool mounting surface of the robot hand 7a may be made to coincide with this point, and the displacement of each axis at that time may be used as base data.

FIG. 3 is a circuit block diagram for realizing the articulated robot control method according to the present invention.

In the figure, 51 is a control unit including a central processing unit, and this control unit 51 includes a memory 52 . Memory 53 consisting of RAM, teaching operation i54. An operation panel 55 having a cRT display device and a tape reader 56 are attached.

The memory 52 stores various control programs to be executed by the control unit 51. The memory 53 stores the teaching operation f
Manually input teaching data from the f154, operation panel 55, tape league 56, etc., data input from the operation panel 55, and results and data of calculations performed by the control unit 51 are stored.

The teaching operation panel 54 has a numerical display, lamps, and operation buttons necessary for operating the articulated robot. The operation panel 55 has various keys such as a numeric keypad and function keys in addition to a display device including a CRT, and inputs various data from the outside to the NC device. 60 is an axis controller including an interpolator that controls multiple axes; 59 is a servo circuit that controls the drive source of the articulated robot 58; 64 is an input/output circuit; 57 is an input/output circuit that performs signal input/output operations between 66 is a bus line 7'J. Next, the hand control method of the present invention will be explained step by step with reference to the flowchart shown in FIG.

First, a manual feed command is given to the hand from the teaching operation panel 54, and the center point of the tool mounting surface of the hand is set at the tip 1 of the jig 15.
Match 5a. The displacement data of each axis at that time is fed back and recorded as base data in the memory 53.Next, a predetermined tool is mounted on the hunt, and the tip of the tool is set by manual feeding again to match the tip 15a of the jig 15. let The displacement of each axis at this time is compared with the base data, the control unit 51 calculates the reference point data that becomes the reference for coordinate transformation, and the axis posture is further changed to align the tool tip with the fixed point multiple times, each time. Rewrite the reference point data.

When the reference point data is completed in this way, the setting jig 15
If the hand control command is generated by teaching the tool position, speed, and work command, the accuracy of the trajectory at the time of play puncture will be improved, and the calculation error in the control unit 51 will also be reduced. Even when hand control is performed by replacing various types, reference point data can be easily set, and accurate control commands for each axis can be generated in accordance with work commands.

Although the present invention has been explained using an example in which the present invention is applied to a welding robot, the present invention is not limited to the above-mentioned example. For example, the present invention may be applied to a painting robot, or may be applied to a 6-axis industrial robot. can. Furthermore, the structure of the setting jig can be modified in various ways according to the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

(Effects of the Invention) According to the present invention, the hand control device and control method for an industrial robot can control the movement trajectory and tool posture with high precision by controlling the hand using the tool tip as a reference point for coordinate transformation. can be provided.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating the configuration of a hand control device for an industrial robot according to the present invention, and FIG. 2 is a side view showing the relationship between the arm of the articulated robot and a fixed point setting jig according to the present invention. Fig. 3 is a block diagram of the articulated robot control system according to the present invention, Fig. 4 is a flowchart of the operation showing an example of the method of the present invention, Fig. 5 is a perspective view of a 5-axis industrial loft, and Fig. 6 is a FIG. 3 is an enlarged view of the wrist, hand, and tool. 7a...hand, 8...tool, 11...base data storage section, 12...fixed point data storage section, 13...
- Reference point data storage unit, 14...Each axis target position determination unit, 15...Setting jig, 51...Control unit, 52...
Memory (ROM), 53...Memory (RAM), 54
... teaching operation panel, 55 ... operation panel, 56 ... tape league, 58 ... articulated robot, 59 ... servo circuit, 60 ... axis controller. Patent applicant: Representative of FANUC Co., Ltd. Patent attorney: Minoru Tsuji Figure 4

Claims (3)

[Claims] (1) In an industrial robot hand control device that controls the position and orientation of a tool attached to a robot hand while aligning each axis of the robot with a target value, the center point of the tool attachment surface of the robot hand means for storing the displacement of each axis as base data when the tip of the tool matches a predetermined point in the robot reference coordinate system; means for setting a fixed point such that the
means for comparing the displacement of each axis when it coincides with the fixed point with the base data and storing it as reference point data for coordinate transformation; and determining the target position of each axis of the robot based on the data regarding the tool position and orientation. 1. A hand control device for an industrial robot, comprising: means for controlling a hand using a tool tip as a reference point for coordinate transformation in accordance with a predetermined work command by the tool. (2) The hand control device for an industrial robot according to claim 1, wherein the means for setting the fixed point is an end point of a setting jig fixed to a robot reference plane. (3) In an industrial robot hand control method in which the position and orientation of a tool attached to a robot hand are controlled while each axis of the robot matches a target value, the center point of the tool attachment surface of the robot hand a step of aligning the tip of the tool with a fixed point of the robot reference coordinate system and storing the displacement of each axis at that time as base data; and a step of changing the axis posture of the tip of the tool and aligning it multiple times with the fixed point of the robot reference coordinate system. , the step of comparing the displacement of each axis when it coincides with the fixed point with the base data and storing it as reference point data for coordinate transformation, and controlling the tool position and orientation based on the reference point data. A hand control method for an industrial robot, characterized in that: