JPH0473161B2 - - Google Patents

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 operational error during operation, or if a setup change is required to perform a different task, or if the robot needs to be taught the next task, the operator must Within this range of motion, it is necessary, for example, to remove workpieces that have failed to be delivered or to teach new motions to the robot.

In such cases, if the robot continues to operate or if the operator makes a mistake in teaching the robot, the operator may collide with the robot's arm, get caught in the robot's rotation, or even be caught. And it's very dangerous.

As a means for this purpose, there is a safety device that allows the robot to start various operations after turning off the power switch or pressing a switch that stops the robot's operation. There are also safety devices that are 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 completely unable to operate, making it impossible to perform teaching work. Moreover, once the power is turned off, the settings for determining the robot's current position must be reconfigured when the robot is restarted.

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

Moreover, in these cases, it is not possible to deal with the case 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 used even if a person inadvertently enters the robot's operating range. However, with this configuration, it is difficult to set limits between the robot's normal operating load and overload due to obstacles, and incorrect settings may hinder robot operation or be dangerous. . not only that,
There is a problem in that it also interferes with the teaching operation.

Furthermore, in each of the above-mentioned devices, the operation of the robot is uniformly stopped or continued, regardless of the operation status of the robot or the position of the operator. Therefore, it has become difficult to ensure prompt and appropriate safety measures depending on the situation.

The present invention was made to solve the above-mentioned problems, and determines the necessity of an emergency stop, etc. according to the dangerous operating range of the robot, the position of the worker, etc., and stops the robot within the operating range of the robot. It is an object of the present invention to provide a safety device that can quickly and reliably ensure safety without impeding 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. 1.

In order to solve the above-mentioned problems in a safety device installed in a robot which is equipped with a drive control means and which operates automatically under the drive control of the drive control means according to a taught operation program, the present invention provides the following: It is characterized by having the following configuration requirements.

(a) An intrusion detection means which divides the operating range of the robot into a plurality of sections, and arranges in each section a detection element for detecting 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 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 are each held in a register, and the register is stored in the register. Calculate the absolute value of the difference between the held intrusion section signal and arm position signal, and compare it with a preset value of the distance between the robot arm and the intruder to calculate the degree of approach of the intruder to the robot arm. calculation means.

(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 performed, and both
Command selection means for instructing the drive control means to perform feed hold when the distance is out of the range.

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

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

As the detection element arranged in each compartment, a mat switch or the like can be used, for example, and the intrusion detection means is constituted by placing this within the dangerous operating range of the robot. When a person enters the robot's dangerous range and steps on the matsu switch, it is activated and detects that a person has entered the area.

Note that the intrusion detection means may use other detection elements as long as they have the same function. For example, an element that detects a change in capacitance due to contact with a human body can 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 rotation, the arm position is divided into at least N equal parts and each position is displayed.

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

In the third component, the calculation 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 detection element of the intrusion detection group. For example, it can be configured by a microprocessor and a group of registers.
Each of the detection signals mentioned 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 constituted by, for example, a microcomputer, 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, and whether the robot should be held or not. Determine whether the operation should continue. Then, based on the result of the determination, a command is given to the drive control means to stop the operation of the robot, etc. Further, the robot operation 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 dangerous operating range into multiple sections and arranging a detection element in each section, it is possible to accurately locate a worker, etc. when they enter the range. to be detected. In particular, if the robot arm is divided radially, the distance between the rotational position of the robot arm and the position of the intruder can be easily determined, and the degree of approach can be clearly determined. For example, when the operational danger range is equally divided into N sections, consecutive codes are assigned to each section B1 to Bn so that each section can be identified.

In addition, the intrusion zone detection signal from each detection element is
Numerical values from 1 to n, each indicating the position of the corresponding section, are included as codes.

Further, in the above configuration requirement (b), the arm position detection means and the drive direction detection 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 from 1 to 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 selects an "emergency stop" when the robot and the intruder are closer than a preset range.
Furthermore, when both of them are apart from the above range, the drive control means is commanded to perform "feed hold". For example, if the absolute value of the code difference between the intrusion zone detection signal and the arm position detection signal is less than 1, an "emergency stop" is immediately commanded, and 1
If the condition is larger, “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 the 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 enters the robot's dangerous operating range. This embodiment also has a function to automatically stop the workpiece table even if the workpiece table is pulled out into the robot's dangerous range of operation, thereby avoiding a collision between the arm and the table.

First, an overview 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 attached to the robot body Rb. As its main components,
The controller 10 that constitutes the calculation means and command selection means, the matsu switch group 20 that constitutes the intrusion detection means, the encoder 30 that constitutes the arm position detection means, and the drive control means that drive the robot. Drive control device 4 that performs control
0, and a teaching operation panel 5 constituting the movement teaching means.
0, and a drive device 60 that drives the robot arm Ra to rotate 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 turns, the dangerous operation range A is defined as a turning trajectory whose turning radius is the state in which the arm Ra is fully extended. The operational danger range A is equally divided into N working zones B1 to Bn.

The control unit 10 includes a CPU 11, a register group 1
2. Arithmetic means 13, display device 14a, input/output circuit 14b, and read-only memory
It has a ROM 15, an external storage device 16, an input interface I/F 17, an input/output interface I/F 18, and an arm position converter 19, which are connected by a bus BUS.

The CPU 11 controls various devices connected to the control unit 10. For example, it has functions such as input/output control of various signals, control of the calculation means 13, and selection of commands for controlling the operation of the robot based on the calculation results. Read only memory ROM15
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, a platform position register 12b that indicates the drawer and position By of the platform, and an arm position signal that indicates the current position of the robot arm. The robot current position register 12c that holds Rp, the robot drive direction register 12d that holds the drive direction detection signal F that indicates the robot drive direction, and the difference number that becomes the deceleration position.
A deceleration position register 12e that sets T1, a feed hold stop position register 12f that sets the difference T2 that becomes the feed hold stop position, and an emergency stop position register 12g that sets the difference T3 that becomes the emergency stop position. Become.

The calculation means 13 has a subtracter, and the CPU
Under the control of 11, the following equation is calculated.

Tx=|Bx−Rp| Ty=|By−Rp| The display device 14a is a cathode ray display tube.
Consists of CRT and keyboard KB. display tube
The CRT displays the numerical values of the register group, the calculation results of the calculation means 13, etc. via the input/output circuit 14b. The keyboard KB changes the numerical values, etc. of the register group through the input/output circuit 14b.

The external storage device 16 includes, for example, a magnetic tape device, a magnetic disk device, etc., and stores data taught to the robot.

The mat switch group 20 is composed of a plurality of switches SW1 to SWn, and is arranged in each section set by dividing the dangerous operation range A. That is, at least one is disposed in each of the work sections B1 to Bn. In this embodiment, one is placed in each section.
The matsu switch group 20 is configured to turn on when the user steps even one step into the compartment.

The switches SW1 to SWn are all connected to an input interface I/F 17, and their on/off status is input to the control section 10. Each switch SW1
~SWn are 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 FIG. 2, for convenience of illustration, the matsu switch group 20 is shown outside the compartments, but in reality they are installed inside each compartment.

The encoder EC30 includes, for example, a disk 31 on which a certain code pattern is formed by through holes, shading marks, etc., and a photocoupler, reed switch, etc.
The code pattern reading element 32 is configured. This echoda is installed in the drive part of the arm,
Outputs signals such as pulses in response to the rotation angle of the arm. The output of the reading element 32 is passed through the input/output interface I/F 18, and the converter 19 converts the captured current value data into data corresponding to each section of the matsu switch group 20, and stores it in the robot current position register 12c. Sent.

The drive control device 40 of the robot Rb is connected to the CPU 11 via the input/output interface I/F 18, and controls the drive device 60 in accordance with the instructions thereof. Further, a teaching operation panel 50 is connected to the drive control device 40. This teaching operation panel 50
A mode selector 51 is provided for selecting whether the robot is to perform normal operation or teaching operation.

The drive device 60 includes a motor 61 for rotating the robot arm, 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. Ru. This interpolator 64 inputs the robot drive direction register 1 via the input/output interface I/F 18.
2d, and is configured to send out a drive direction detection signal corresponding to the polarity of the drive current supplied to the motor 61.

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

When operating the safety device of this embodiment,
First, fixed data is set in part of the register group 12.

That is, first, the position By of the table (see FIG. 4) is set in the table position register 12b using a preset code. The distance T1 between the robot arm in a state to be decelerated and the intruder (or the stand) is set in the deceleration position register 12e. In this example,
This is designated as "2".

In addition, the feed hold position register 12f
Then, set the distance T2 between the robot arm, which should be stopped in the feed hold state, and the intruder (or the stand). In this example, this is set to "1".
It is said that

Further, 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".

Furthermore, during the operation of the safety device of this embodiment,
The CPU 11 loads constantly changing variable data into registers other than those mentioned above. The intruder's position Bx is stored in the intruder position register 12a, and the robot arm's position is stored in the robot current position register 12c.
Rp is input into the robot drive direction register 12d as the rotation direction F of the robot arm.

In this situation, first, the CPU 11
Check whether the robot is in operation (step 1).
This is, for example, input/output interface I/F1
This is done by checking the operating status of the drive control device 40 via 8. If the robot is in operation, proceed to the next step 2. If it is not in operation, the determination in step 1 is repeated.

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 table is pulled out, and if this bit is "0", it is determined that it is not pulled out.

Here, if this flag bit is "0", the CPU 11 proceeds to step 3 and checks via the input interface I/F 17 whether any of the steps SW1 to SWn is on.
If none of the switches are turned on, return to step 1 and repeat the above operation. However, when any switch is on, CPU11
imports the discrimination data. That is, the information Bx representing the position of the intruder, the current position Rp and the driving direction F of the robot arm are acquired (step 4),
The current position Rp is converted into section data corresponding to the matsu switch group 20 (step 5).

Next, the CPU 11 uses the calculation means 13 to calculate the absolute value Tx of the difference between the above Bx and Rp, and calculates the absolute value Tx of the difference between the above Bx and Rp.
It is determined whether the following is true (step 6). if,
If it is less than 1, an emergency stop command is issued (step 11).

On the other hand, if the above calculation result is greater than 1,
The absolute value Tx of the difference between Bx and Rp is calculated, and it is determined whether it is less than or equal to 2 (step 7). If it is less than 2, a deceleration command is issued (step 12).

Also, if the above calculation result is greater than 2,
The absolute value Tx of the difference between Bx and Rp is calculated, and it is determined whether it is less than or equal to 1 (step 8). After the deceleration command is issued, if the absolute value Tx becomes 1 or less, a feed hold stop command is issued (step 13).
On the other hand, if it is greater than 1, the process returns to step 7 and the above operation is repeated.

By the way, if the table is pulled out in step 2 above, the CPU 11 executes step 9.
Then, the calculation means calculates the absolute value Ty of the difference between the position information By of the stand and the current position Rp of the robot arm, and it is determined whether the result reaches 2 (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 position information of the stand
The absolute value Ty of the difference between By and the current position Rp of the robot arm is calculated by the calculation means, and the result is 1
Determine whether the following is true (Step 10). If it is less than 1, issue an emergency stop command (step
11). Here, if it is greater than 1, the process returns to step 9 and the above operation is repeated.

[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 danger range of robot movement and the position of the worker, and stops the worker from entering the robot's movement range. This has the effect of quickly and reliably ensuring safety without interfering with work efficiency, against inadvertent intrusion by workers, or during robot operation teaching work by workers.

[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, and FIG. 3 is a flowchart showing the operation of the above embodiment. Figure 4 shows
FIG. 4 is an explanatory diagram showing the positional relationship between the robot arm, the intruder, and the workpiece table. 11...CPU, 12...Register group, 13...
...Arithmetic means, 17...Input interface, 18
... input/output interface, 20 ... matsu switch group, 30 ... encoder, 40 ... drive control device, 50 ... teaching operation panel, 60 ... drive device.

Claims (1)

[Scope of Claims] 1. A safety device provided in a robot that is equipped with a drive control means and that operates automatically under the drive control of the drive control means according to a taught operation program, which includes: (a) (b) a position of the robot arm; (c) an intrusion section detection signal sent from the intrusion detection means and indicating the detected section; The arm position signal and drive direction detection signal are held in registers, and the absolute value of the difference between the intrusion section signal and the arm position signal held in these registers is calculated, and the robot arm and the intruder are detected in advance. (d) calculating means for calculating the degree of approach of the intruder to the robot arm by comparing the distance value; When there is an emergency stop, both parties
A safety device for a robot, comprising: a command selection means for instructing the drive control means to set the drive control means to a feed hold when the robot is away from the above range.