JPS61206002A - Safety device for robot - Google Patents

Abstract

PURPOSE:To execute the securing safely, rapidly and without fail without obstructing the working efficiency by calculating the approach degree of an invader from an invaded division detecting signal, an arm position signal and a driving direction detecting signal and executing the robot driving control in accordance with the calculated results. CONSTITUTION:For an invaded division detecting means, detecting elements 1-n are arranged in respective divisions where the robot action scope is divided, and an invaded division detecting signal is outputted in accordance with those detecting signals. An arm position detecting means and a driving direction detecting means respectively detect the position of the robot arm and the position of the swing motion angle and output an arm position signal and a driving direction detecting signal. A calculating means inputs these respective output signals and calculates the approach degree of the invader for the robot arm. A command selecting means, based upon the calculated result, commands a driving control means to stop at the time of emergency when a robot and an invader approach from the set scope and to feed-hold when they are away from the scope.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a robot that is equipped with a drive control means and a motion teaching means, stores a taught motion program, and automatically executes the motion. Regarding safety equipment.

[Prior Art] In recent years, robots have been used to transport workpieces in processing machines. This robot normally operates automatically according to a preset or taught operation program.

On the other hand, if the robot makes some kind of mistake during operation, if a setup change is required to perform another task, or if the robot needs to be instructed on the next task, the operator must Within the robot's range of motion, for example, it is necessary to remove workpieces that have failed to be delivered or to teach the robot new motions.

In such cases, if the robot continues to move or if the worker makes a mistake in teaching the robot's motion, the worker may collide with the robot's arm, get caught in the robot's turning motion, or even get caught. Yes, it is very dangerous.

As a means for this purpose, there is a safety device that turns off the robot's power switch or presses a switch that stops the robot's operation before starting various tasks. There is also a safety device that is configured to make an emergency stop if an overload is applied to the robot.

[Problems to be Solved by the Invention] However, in these safety devices, there is a problem in that when the power switch is turned off, the robot becomes unable to operate at all, making it impossible to perform teaching work. Furthermore, once the power is turned off, the settings for determining the robot's current position must be reconfigured when restarting.

Further, in a configuration in which work is performed after turning off the operating switch, there is a danger that the operator may forget to turn off the switch and enter the operating range of the robot, which is dangerous.

Furthermore, in these cases, it is not possible to deal with cases where a person inadvertently enters the operating range of the robot, which is dangerous.

On the other hand, if the robot is configured to stop when an overload is applied to it, it can be reused even if one person inadvertently enters the robot's operating range. However, with this configuration, it is difficult to set the limit between the robot's normal operation load and overload due to obstacles, and incorrect settings may hinder the robot's operation or be dangerous. . In addition to this, there is a problem in that the teaching operation is also hindered.

Furthermore, in each of the above-mentioned devices, the operation of the robot is routinely stopped or continued, regardless of the operation status of the robot or the position of the worker. This makes it difficult to ensure prompt and appropriate safety measures depending on the situation.

The present invention was made to solve the above-mentioned problems.The present invention determines the necessity of an emergency stop, etc. according to the robot's dangerous range of motion, the position of the worker, etc., and controls the robot's range of motion. It is an object of the present invention to provide a safety device that can quickly and reliably ensure safety without interfering with work efficiency against inadvertent intrusion by workers or during robot operation teaching work by workers.

[Means for Solving the Problems] Means for solving the above problems will be explained with reference to FIG.

In order to solve the above-mentioned problems in a safety device installed in a robot that is equipped with a drive control means and automatically operates under the drive control of the drive control means in accordance with a taught operation program, the present invention has the following features: Next structure! & requirements.

(a) Divide the operating range of the robot into multiple sections,
An intrusion detection means comprising a detection element arranged in each section to detect whether or not a person is intruding into the section.

(b) Arm position' detection means for detecting the position of the robot arm and drive direction detection means for detecting the drive direction.

(c) The approach of the intruder to the robot arm is determined based on the intrusion section detection signal sent from the intrusion detection means and indicating the detected section, and the arm position signal and drive direction detection signal sent from the arm position detection means. Arithmetic means for calculating degrees.

(d) Based on the calculation results of the calculation means, if the robot and the intruder are closer than a preset range, an emergency stop is applied, and if the robot and the intruder are further away than the above range, a feed hold is applied. command selection means for instructing the drive control means to

Each of the above constituent requirements will be explained in more detail.

In the first component above, the robot's motion area can be divided into multiple sections depending on the robot's motion mode, but the circle formed by the robot arm's turning trajectory is defined as the motion danger range. It would be common to divide radially into N equal parts.

For example, a mud switch or the like can be used as the detection element disposed in each compartment, and this is installed within the dangerous operation range of the robot to constitute the intrusion detection means. When a person enters the robot's dangerous operating range and steps on this mud switch, it is activated and it is detected that a person has entered the area.

Note that the intrusion detection means may use any other detection element as long as it has a similar function; for example, an element that detects a change in capacitance due to contact with a human body may be used.

In the second component, the arm position detection means is constituted by, for example, a rotary encoder, and outputs a signal such as a pulse in accordance with the rotation angle of the arm. This signal is configured to display the arm position in correspondence with the division of the dangerous operation range into a plurality of sections. When the dangerous operation range is divided into N equal parts over one round, the arm position is also divided into N equal parts and each position is displayed.

Further, the driving direction detecting means may be constituted by, for example, the above-mentioned rotary encoder, or may be configured to detect the turning direction of the driving device that turns the robot based on the polarity.

In the third component, the calculating means compares and calculates the driving direction of the robot arm and the current position of the robot arm with respect to the position of the intruder indicated by the intrusion zone detection signal from the sensing element of the intrusion detection group. For example,
It can be configured with a microprocessor and a group of registers.

Each of the detection signals described above is stored in a group of registers, and a microprocessor performs arithmetic operations using them. That is, the calculation means is configured to compare the detection signals from the intrusion detection means, the arm position detection means, and the drive direction detection means to warn against human intrusion into the robot's dangerous operating range.

In the fourth component, the command selection means is configured with a microcomputer, for example, and grasps the operating state of the robot based on the calculation result of the calculation means, and determines whether the robot should be stopped or not, whether the robot should be stopped or not, and whether the robot should be held or not. Decide whether or not to proceed. Based on the judgment result,
It instructs the drive control means to stop the operation of the robot, etc.

Further, the robot motion teaching means is permitted to perform teaching operations.

[Operation] The operation of the solution means of the present invention configured as described above will be explained with reference to FIG. 1.

In configuration requirement (a) above, by dividing the robot's operational danger range into multiple sections and arranging a detection element in each section, if a worker, etc. enters the range, the position can be accurately determined. to be detected. In particular, if the area is divided radially, the distance between the rotational position of the robot arm and the intruder's position can be easily determined, and the degree of approach can be clearly determined. , each section Bl-an is given a consecutive code so that each section can be identified.

In addition, the intrusion section detection signal from each detection element is as follows.

Numerical values l-n are included as codes, each indicating the position of the corresponding section.

In addition, in the above configuration requirement (b), arm position detection,
The means and the driving direction detecting means detect the rotation angle position of the robot arm and also detect the rotation direction, that is, whether it is clockwise or counterclockwise. This result is sent to the arithmetic means.

Here, the arm position detection means displays the arm position using a code consisting of a numerical value of 1-n in correspondence with the intrusion section detection signal.

In the above configuration requirement (c), the calculation means is configured to generate an intrusion section detection signal sent from the intrusion detection means and displaying the detected section, and an arm position signal and a driving direction detection signal sent from the arm position detection means. From this, the degree of approach of the intruder to the robot arm is calculated. This calculation is performed, for example, by determining the absolute value of the difference between the two codes, since both the intrusion section detection signal and the arm position detection signal are composed of corresponding numerical codes.

Note that the calculation of the above absolute value is performed in the direction in which the arm and the intruder approach, taking into consideration the driving direction of the arm.

Based on the calculation result of the calculation means, the command selection means causes an "emergency stop" when the robot and the intruder are closer than a preset range, and when both are closer than the range set in advance. When the user is away, the drive control means is commanded to enter "feed hold". For example, if the absolute value of the code difference between the intrusion section detection signal and the arm position detection signal is smaller than l, the "emergency stop" is immediately executed. command, and if it is larger than the "feed hold"
shall be.

In reality, the reference value is set as appropriate, and various commands such as "emergency stop", "feed hold", "deceleration command", and "maintain status quo" are selected, taking into consideration the passage of time.

[Example] Examples of the present invention will be described with reference to the above-mentioned FIGS. 2 to 4. Furthermore, Fig. 2 is a block diagram showing one embodiment of the safety device of the present invention, Fig. 3 is a flowchart showing the operation of the above embodiment, and Fig. 4 shows the positional relationship between the robot arm, the intruder, and the workpiece table. FIG.

<Configuration of Embodiment> The robot safety device of the present invention shown in FIG. 2 is a device that automatically stops the operation of the robot when a worker or the like intrudes into the dangerous range of operation of the robot. Note that this embodiment also has a function to automatically stop the workpiece table even when the workpiece table is pulled out into the dangerous range of operation of the robot to avoid collision between the arm and the table.

First, the outline of the configuration of the apparatus of this embodiment will be explained with reference to FIG.

This embodiment is applied to a robot consisting of a robot body Rb and an arm Ra rotatably provided on the robot body Rb. Its main components include a control unit 1G which constitutes the calculation means and command selection means, a mud switch group 20 which constitutes the intrusion detection means, an encoder 30 which constitutes the arm position detection means, and the drive control unit 1G. A drive control device 4 that constitutes means and controls the drive of the robot.
0, a teaching operation panel 50 constituting the movement teaching means,
The robot arm Ra is provided with a drive device BO that swings and drives the robot arm Ra and constitutes the drive direction detection means.

Next, the above configuration will be explained in more detail.

Regarding the range in which the arm Ra of the robot above rotates,
The operating dangerous range A is defined as a turning locus whose turning radius is the state in which the arm Ra is extended to its maximum extent. This operational danger range A is equally divided into N work sections Bl to Bn.

The control unit IO includes a CPU 11, a register group 12, a calculation means 13, a display device 14a, an input/output circuit 14b, a read-only memory ROM 15, an external storage device 18, an input interface I/F 17,
It has an input/output interface I/F 18 and an arm position converter 19, which are connected by a bus BIJS.

The CPU II controls various devices connected to the control unit 10. For example, the CPU II has functions such as input/output control of various signals, control of the calculation means 13, and selection of commands to control the robot's operation based on the calculation results. has. Read-only memory ROW 15 stores a program that controls this CPU 11.

The register group 12 includes an intruder position register 12a that holds an intrusion zone detection signal Bx indicating the intruder's position, and a platform position register 12b that indicates the drawer and position By of the platform.
and an arm position signal R indicating the current position of the robot arm.
A robot current position register 12c that holds p, and a robot drive direction register that holds a drive direction detection signal F that indicates the robot drive direction! 2d, a deceleration position register 12a that sets the number of differences Tl that becomes the deceleration position, a feed hold stop position register 12F that sets the number of differences T2 that becomes the feed hold stop position, and a number of differences T3 that becomes the emergency stop position. It consists of an emergency stop position register 12g.

The calculation means 13 includes a subtracter, and under the control of the CPU 11 performs the calculation of the following equation.

T! = l 8-fold - Rp 1 Ty = I By-h l The display device 14a has a 0 display tube CRT consisting of a cathode ray display tube CRT and a keyboard KB. 13
Displays the calculation results, etc. The keyboard KB changes the numerical values, etc. of the register group through the input/output circuit 14b.

The external storage device 1θ includes, for example, a magnetic tape device, a magnetic disk device, etc., and stores data taught to the robot.

The mud switch group 20 includes a plurality of switches SWI
~SWn, and are arranged in each section set by dividing the dangerous operation range A. That is, each section 81-B! At least one is placed in the work area of I.

In this embodiment, one is placed in each section. The mud switch group 20 is configured to turn on when the user steps even one step into the compartment.

All of the switches 5WI-SWn are connected to an input interface I/F 17, and their on/off status is input to the control section 10. Each of the switches SW1 to SWn is numerically coded, and when a certain switch is turned on, the code of that switch is sent to the CPU 11 via the input interface I/F 17.

In addition, in FIG. 2, for convenience of illustration, the mud switch group 20 is shown outside the above-mentioned sections, but in reality, it is installed inside each section.

The encoder EG30 includes a disk 31 on which a fixed code pattern is formed by, for example, through holes, shading marks, etc., and a code pattern reading element 32 such as a photocoupler or a reed switch. The output of the reading element 32 is
Via the input/output interface I/F 18, the current value data taken in is converted by a converter 19 into data corresponding to each section of the mud switch group 20, and sent to the robot current position register 12c.

Robot)Rh drive control system! ! 40 is connected to the CPU 11 via the input/output ink face I/F 18,
The drive device 80 is controlled according to the command. Further, a teaching operation panel 50 is connected to the drive control device 40. The teaching operation panel 50 is provided with a mode selector 51 for selecting whether the robot is to perform normal operation or teaching operation.

The drive device 60 includes a motor 8 that rotates the robot arm.
1, an amplifier 62 for driving the motor 61, a speed detector 63 for the motor 61, and an interpolator 64 for distributing pulses and the like. This interpolator 64 is connected to the robot drive direction register 12d via the input/output interface I/F 1B, and is configured to send out a drive direction detection signal corresponding to the polarity of the drive current supplied to the motor 61. There is.

<Operation of the Embodiment> Next, the operation of the apparatus of this embodiment configured as described above will be explained with reference to the flowchart of FIG. 3.

To operate the safety device of this embodiment, first, fixed data is set in a part of the register group 12.

That is, first, the position B of the table is entered in the table position register 12b.
y (see FIG. 4) is set using a preset code. In the present embodiment, the distance between the robot arm in a state to be decelerated and the intruder (or the stand) is set to 1 in the deceleration position register 12e.

Further, in the present embodiment, a distance of 2 between the robot arm that should be stopped in the feed hold state and the intruder (or the stand) is set in the feed hold position register 12F, and this is set to "1".

Furthermore, the distance T3 between the robot arm in a state where an emergency stop is to be made and the intruder (or stand) is set in the emergency stop position register 12g. In this embodiment, this is set to "1".

In addition, the safety device of this embodiment has the ability to
tt, the constantly changing fluctuating data is loaded into the registers other than the above, the position Bx of the intruder is stored in the intruder position register 12a, the position Rp of the robot arm is stored in the robot current position register 12c, and the robot arm position Rp is loaded into the register 12c. The direction F of the turning force of the robot arm is input into the direction register 12d.

In the situation like 1-2, first, the CPU 11 checks whether the robot is in operation (step 1).

This is done, for example, by checking the operating status of the drive control device 40 via the input/output interface INF 18.If the robot is in operation, proceed to step 2; Repeat the judgment in step 1.

In step 2, the CPU 11 checks the table position register 12b to check whether the table has been pulled out. This can be easily done by providing a flag bit in the table position register 12b. That is,
If this bit is "1", it is determined that the stand is being pulled out, and if this bit is "0", it is determined that it is not being pulled out.

Here, if this flag bit is O'', then CP
U 11 proceeds to step 3 and inputs the input interface I
/F Through 17, any switch 5lll~gW
Check whether n is on. If none of the switches is on, the process returns to step 1 and the above operation is repeated. However, if any of the switches is on, the CPU 11 imports discrimination data, that is, detects an intruder. Information indicating the position of B! , take in the current position Rp and driving direction F of the robot arm (step 4),
Current position Rp is.

It is converted into partition data corresponding to the mud switch group 20 (step 5).

Next, the CPt 111 calculates the above B by the calculation means 13.
x and f? The absolute value Tx of the difference between p is calculated and it is determined whether it is less than or equal to 1 (step 6). If it is less than or equal to 1, an emergency stop command is issued (step 11).

On the other hand, if the above calculation result is greater than 1, the above Bt
The absolute value τK of the difference between and Rp is calculated, and it is determined whether it is less than 2 (step 7).

If it is 2 or less, issue a deceleration command (step 1
2).

Furthermore, if the above calculation result is greater than 2, the above Bx
Absolute value T of the difference in kRP! is calculated, and it is determined whether it is less than or equal to 1 (step 8). After the deceleration command is issued, the absolute value T! If it becomes less than l, a feed/hold stop command is issued (step 13). If it is greater than -1, the process returns to step 7 and the above operation is repeated.

By the way, in step 2 above, if the table is pulled out, the CPU 11 branches to step 9 and obtains the position information BY of the table and the current position R of the robot arm.
The absolute value Ty of the difference from p is calculated by the calculation means, and it is determined whether the result reaches 2 or not (step 9). If it is 2, a feed hold stop command is issued (
Step 13).

On the other hand, if it is smaller than 2, the absolute value ry of the difference between the position information ay of the mounting table and the current position IRp of the robot arm is calculated by the calculation means, and it is determined whether the result is less than or equal to 1 (step lO). , if it is less than 1, an emergency stop command is issued (step 11).

Here, if it is greater than 1, the process returns to step 9 and the above operation is repeated.

E. Effects of the Invention] As explained above, the present invention determines the necessity of an emergency stop, etc., depending on the situation such as the robot's dangerous range of motion and the position of the worker, and moves the worker to the robot's motion range. This has the effect of quickly and reliably ensuring safety against inadvertent intrusion by workers or when teaching robot motions to workers without interfering with work efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the robot safety device of the present invention, FIG. 2 is a block diagram showing the configuration of an embodiment of the robot safety device of the present invention, FIG. 3 is a flowchart showing the operation of the above embodiment, and FIG. Figure 4 shows the robot arm,
It is an explanatory view showing the positional relationship between an intruder and a workpiece stand. ll... CPU 12... Register group 13... Arithmetic means 17... Input interface 18... Input/output interface 20... Mad switch group

Claims (1)

[Scope of Claims] A safety device provided in a robot that is equipped with a drive control means and that automatically operates under the drive control of the drive control means according to a taught operation program, comprising: (a) controlling the operating range of the robot; Divide into multiple sections,
(b) arm position detection means and drive direction for detecting the position of the robot arm; and (b) arm position detection means and drive direction for detecting the position of the robot arm. (c) an intrusion section detection signal sent from the intrusion detection means and displaying the detected section; an arm position signal and a drive direction detection signal sent from the arm position detection means; (d) Based on the calculation result of the calculation means, when the robot and the intruder are closer than a preset range, an emergency stop is performed. A safety device for a robot, further comprising: command selection means for instructing the drive control means to perform feed hold when both are separated from the above range.