JPH06320450A - Speed control device for industrial robot - Google Patents

Abstract

PURPOSE:To perform relaxation of collision of a work with a pallet in a way that the work is excessively conveyed by a distance equivalent to a bending amount of an arm when the work is conveyed to a target position by means of a robot. CONSTITUTION:A target position is divided into a plurality of zones and the spring constant of an arm in the direction of gravity in the zone is stored at a spring constant memory device 8. When a work is conveyed, a bending amount is calculated by a means 9 by using the spring constant of a zone corresponding to a zone in which the work is placed. A robot 1 is controlled by a control means 10 such that a speed is adjusted to an allowable value this side of a target position by a distance equivalent to an estimated bending amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling the speed at which a work, particularly a heavy work, is conveyed by an industrial robot of the present invention.

[0002]

2. Description of the Related Art In a transfer robot, a work at a point P1 is gripped and transferred by a hand at the end of an arm and placed at a point P2. At this time, point P2, that is, the target position is designated by coordinates. When a heavy load work is transferred by the transfer robot, the arm bends depending on the weight of the work, so that the actual position of the work differs from the work position recognized by the robot.

Therefore, when placing a work on a pallet,
Due to the bending of the arm, the position of the work may go beyond the position recognized by the robot, the work may collide with the pallet, and excessive shock may be applied to the work.

FIGS. 7 and 8 are views showing a conventional speed control device for an industrial robot, FIG. 7 is an explanatory view of heavy goods transportation by the robot, and FIG. 8 is a speed pattern generation diagram.

In FIG. 7, (1) is a transfer robot, and (1)
(a) is the arm, (2) is the suction hand provided at the tip of the arm (1a), (3) is the heavy work held by the hand (2), and (4) is the work (3). ) Is a pallet.

A conventional speed control device for an industrial robot is constructed as described above, and a control device (not shown) follows an arm (1a) of the robot (1) according to the speed pattern shown in FIG.
Lower the work (3) to the target position. At this time, since the arm (1a) bends due to the weight of the work (3), a difference occurs between the actual work position A and the work position B recognized by the robot (1). 1a) is descending. If you continue descending to the target position in this state, the work will move forward by the amount of deflection C.
(3) may collide with the pallet (4) and receive an excessive impact.

As shown in FIG. 8, the arm (1a) is controlled by a control device with a trapezoidal slow acceleration / deceleration, and at the time t _c before the time t _e to reach the target position, the arm (1a) is moved to the pallet (4). They are in contact, and the speed at that time is V _c .
Further, at this time, the area S _t is the deflection C portion by hatching in the figure.

[0008]

In the conventional speed control device for the industrial robot as described above, the arm (1a) is moved at a speed according to the speed pattern to lower the work (3) to the target position. Therefore, if the work (3) is a heavy object, the arm (1a) bends and the work (3) collides with the target position, giving an excessive impact to the work (3) or the robot (1) itself. There is a problem of danger.

The present invention has been made to solve the above problems, and the first aspect of the present invention alleviates the impact caused by the collision of the work at the target position which is caused by the deflection of the arm when the heavy object is conveyed to the target position. An object of the present invention is to provide a speed control device for an industrial robot that is made possible.

A second invention is, in addition to the object of the first invention, an object of the invention is to provide a speed control device for an industrial robot capable of simply calculating a deflection amount.

In addition to the object of the first aspect of the invention, the third aspect of the invention is capable of inputting necessary information for each of the workpieces in a transfer operation handling a plurality of workpieces and enabling efficient movement. An object of the present invention is to provide a speed control device for such an industrial robot.

[0012]

A speed controller for an industrial robot according to a first aspect of the present invention estimates a flexure amount of an arm caused by a work based on a spring constant in the gravity direction of the arm. Means and control means for controlling the work so that the work speed becomes an allowable speed before the target position by the estimated deflection amount.

The speed controller for an industrial robot according to a second aspect of the present invention uses a spring constant storage means for storing the spring constant of the arm in the gravity direction for each of a plurality of zones divided into target positions, and a workpiece. The amount of arm deflection that occurs
A deflection amount estimating means for estimating the stored spring constant based on the stored spring constant, and a control means for controlling the work to be an allowable speed before the target position by the estimated deflection amount are provided.

Also, in the speed controller for an industrial robot according to the third aspect of the invention, the deflection amount of the arm caused by a plurality of kinds of works is used as the weight of the arm, the weight of each work, and the spring constant of each arm in the gravity direction. Deflection amount estimating means for estimating the work weight based on the estimated amount of deflection from the target position and control means for controlling the work speed to reach the allowable speed before the target position. Is set.

[0015]

In the first aspect of the present invention, the deflection amount of the arm is estimated and the allowable speed is set in front of the target position by the estimated deflection amount, so that the collision of the work at the target position is mitigated. It

Further, in the second invention, since the target position is divided into a plurality of zones and the spring constant of the arm in the gravity direction is set for each zone, the deflection amount of the arm uses the spring constant set for each zone. Calculated.

Further, in the third aspect of the invention, since the weight of each work and the allowable speed at the time of placing the work are set in the hand closing command, necessary information can be easily input for each work.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 6 are views showing an embodiment of the first to third inventions of the present invention. FIG. 1 is a configuration diagram of a main part, and FIG. 2 is a robot of a cylindrical coordinate system for carrying heavy objects. 3 is a side view of the robot, FIG. 3 is an explanatory view of setting a spring constant in a Z direction of a plurality of zones on an XY plane of the robot, FIG. 4 is a velocity pattern generation diagram, FIG. 5 is a structural diagram of a hand closing instruction in a robot language, and FIG. Is a program content diagram using a hand closing instruction, and the same parts as those of the conventional device are denoted by the same reference numerals. Note that FIG. 7 is also used in this embodiment.

In FIG. 1, (6) is a current position storage device for storing the current position of the work (3), (7) is a target position storage device for storing the target position which is the transfer destination of the work (3), 8) is a spring constant storage device for storing the spring constants K _{1 to} K ₇ set in the zones (13a) to (13g) of the target position, which will be described later with reference to FIG.
(9) is a deflection amount estimating means for estimating the deflection amount of the arm (1a) from the stored values of the storage means (7) and (8), and (10) is each storage device (6)
~ (8) and the control means for controlling the robot (1) by the output of the means (9).

In FIG. 2 and FIG. 3, the X of the robot (1)
The operating range (13) on the −Y plane is divided into a plurality (7 in the embodiment) of zones (13a) to (13g), and each zone (1
3a) ~ (13g) arm (1a) Z direction spring constant K ₁
˜K ₇ is calculated and set by the finite element method, and this is stored in the spring constant storage device (8).

Also in the speed control device for the industrial robot configured as described above, the current position stored in the current position storage device (6) and the target position stored in the target position storage device (7) The control means (10) controls the robot (1) to convey the work (3) as in the conventional case. Then, the means (9) searches in which of the zones (13a) to (13g) the target position is, and the spring constant set in the zone and the hand closing command (holding the work (3) in FIG. 5). The deflection amount of the arm is calculated based on the work weight and the hand weight specified by the command).

For example, the target position is the zone (13g),
The values shown in Fig. 5, ie, hand number 1, hand weight 5
0 kg, workpiece weight 100 kg, and when receiving a hand closing command with an allowable speed of 40 mm / sec when placing the workpiece, the arm (1
The amount of deflection S _{t in} a) is calculated by the following equation. S _t = C _s × K ₇ × (50.0 + 100.0) where C _s : safety factor (C _s > 1)

Next, a velocity pattern is generated, as shown in FIG.
As shown in, FIG. 5 is the work place when permissible speed V _cmax input by hand閉命ordinance set such that the speed at the time of collision of the pallet (4), including the deflection amount S _t of the hatched portion The speed pattern is generated so that the area of the speed pattern is the moving distance to the target position.

It should be noted that there are two types of movement, that is, a movement instruction for generating a velocity pattern as shown in FIG. 4 and a movement instruction for not generating such a velocity pattern but performing a normal trapezoidal gentle acceleration / deceleration as shown in FIG. Prepare instructions in robot language. Thus, the movement in the space before placing the work (3) adopts the normal operation, and the movement can be performed efficiently.

Further, as shown in FIG. 6, when a plurality of (3 types) works, that is, IW = 1, IW2, and other works (3) are conveyed, the type of the work (3) may be input from the outside. For example, the work weight VW of the hand closing command and the allowable work placement speed VS are set by the condition judgment sentence composed in the robot language, and the speed control is executed according to the work (3).

[0026]

As described above, in the first invention of the present invention, the amount of deflection of the arm is estimated, and the allowable speed is set to the front by the estimated amount of deflection from the target position. The collision of the work is mitigated, and there is an effect that the work and the robot itself can be prevented from being given an excessive impact.

Further, in the second invention, since the target position is divided into a plurality of zones and the spring constant of the arm in the gravity direction is set for each zone, the deflection amount of the arm is determined by using the spring constant set for each zone. It is calculated, and there is an effect that the amount of deflection can be easily obtained in real time.

Further, in the third aspect of the invention, since the weight of each work and the allowable speed at the time of placing the work are set in the hand closing command, it is possible to easily input the necessary information for each work, and the normal movement command is used. There is an effect that efficient movement can be performed by two types of movement commands, that is, a movement command in which the amount of deflection of the arm is taken into consideration.

[Brief description of drawings]

FIG. 1 is a configuration diagram of essential parts showing an embodiment of the present invention.

2 is a side view of a robot having a cylindrical coordinate system for carrying heavy objects according to FIG. 1;

3 is an explanatory view of setting a spring constant in a Z direction of a plurality of zones on an XY plane of the robot shown in FIG.

FIG. 4 is a velocity pattern generation diagram showing an embodiment of the present invention.

FIG. 5 is a structural diagram of a robot language hand closing instruction according to an embodiment of the present invention.

6 is a program content diagram using the hand close instruction of FIG.

FIG. 7 is an explanatory diagram of a heavy load transport showing a conventional speed control device for an industrial robot.

FIG. 8 is a velocity pattern generation diagram of the robot of FIG.

[Explanation of symbols]

 1 Robot 1a Arm 2 Hand 3 Work 4 Target Position (Pallet) 8 Spring Constant Memory 9 Deflection Estimating Means 10 Control Means 13a-13g Zone

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 12, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

For example, the target position is the zone (13g),
The values shown in Fig. 5, ie, hand number 1, hand weight 5
0 kg, workpiece weight 100 kg, and when receiving a hand closing command with an allowable speed of 40 mm / sec when placing the workpiece, the arm (1
The amount of deflection S _{t in} a) is calculated by the following equation. S _t = C _s × 1 / K ₇ × (50.0 + 100.0) where C _s : safety factor (C _s > 1)

Claims (3)

[Claims] 1. A robot that conveys a work by an arm and speed-controls the work so that the work is decelerated to an allowable speed and placed at a target position. The deflection amount of the arm caused by the work is a spring in the gravity direction of the arm. Industrial use, characterized by comprising a deflection amount estimating means for estimating based on a constant, and a control means for controlling the workpiece so that the allowable speed is obtained in front of the target position by the estimated deflection amount. Robot speed controller. 2. A robot that conveys a work by an arm and controls the speed of the work such that the work is decelerated to an allowable speed and placed at a target position, wherein a plurality of spring constants of the arm in the gravity direction are divided into the target positions. A spring constant storage device for storing each zone is provided, and the deflection amount estimating means for estimating the deflection amount of the arm caused by the workpiece based on the stored spring constant, and the workpiece from the target position above the estimated deflection. A speed control device for an industrial robot, comprising: a control means for controlling the above-mentioned permissible speed by a predetermined amount. 3. A robot that holds a plurality of types of works by hand closing commands, conveys them by an arm, and controls the speed so that each work is decelerated to an allowable speed and placed at a target position. Deflection amount estimating means for estimating the amount of deflection of the arm based on the weight of the arm, the weight of each work, and the spring constant of each arm in the gravity direction, and the estimated amount of deflection of each work above the target position. A speed control device for an industrial robot, comprising: a control means for controlling the speed so that the speed is just before this amount, and setting each of the work weight and the allowable speed in the hand closing command.