JPH04152091A - Emergency stop device for robot numerical control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The emergency stop device of the robot numerical control device of the present invention will be described in detail according to the following items.

A. A. Field of industrial application B9 Summary of the invention C0 Prior art D1 Problem to be solved by the invention [Figure 4] E9 Means for solving the problem F. Examples [Figures 1 to 3] a , Configuration [Figure 's1] b. Example of emergency stop procedure [Figure 2] b-11 procedure (A) b-2, procedure (B) b-31 procedure (C) b-40 procedure CD) C3 emergency stop process [FIG. 3] G0 Effect of the invention (A, industrial application field) The present invention relates to a novel emergency stop device for a robot numerical control device. Specifically, the present invention aims to provide a novel emergency stop device for a robot numerical control device that can precisely perform emergency stop processing appropriate for each degree of freedom, motion state, etc. of the robot.

(B. Summary of the Invention) The emergency stop device of the robot numerical control device of the present invention includes a command means for giving a command to the stop means for stopping the motion of each axis constituting the robot during an emergency stop of the robot. This is an emergency stop device for a robot numerical control device, which includes a characteristic storage means for pre-holding information regarding load characteristics regarding the robot's degree of freedom, a motion state detection means for detecting the motion state of each axis, and a plurality of emergency stop devices. A stop procedure storage means is provided which stores control commands regarding the stop procedure in advance, and at the time of an emergency stop, the command means receives information regarding the characteristics of each degree of freedom from the characteristic storage means and information regarding the motion state of each axis from the motion state detection means. In response to this, the emergency stop procedure corresponding to this information is read from the stop procedure storage means, and
According to the content of the control command related to the procedure, a signal is sent to the stopping means to perform the stopping process for each degree of freedom of the robot.This allows the robot to control the nature of the load due to the influence of inertia, etc., and the motion of each degree of freedom of the robot. Emergency stop processing is performed according to the situation, preventing an increase in load torque, a decrease in positional accuracy, and the occurrence of vibrations that would occur with an emergency stop, and also eliminating the inconvenience of being unable to predict the robot's stopping posture. .

(C, Prior Art) In order to avoid dangers such as robot runaway, robot controllers have conventionally provided some kind of emergency stop means.

In other words, when an error signal that requires an emergency stop is detected, or when an external emergency stop command is input to the robot controller, power is not supplied to the robot's drive source (motor, etc.). Emergency stop procedures are taken, such as cutting off the power supply, short-circuiting the regenerative resistor as necessary, and stopping the drive source after limiting the driving force with a mechanical brake.

By the way, regarding such an emergency stop procedure, the ml
The goal is to perform an emergency stop quickly and stop the robot's motion in the shortest possible time.

Therefore, the above-described means such as regenerative resistance and mechanical brakes are not provided for all degrees of freedom of the drive system, but are provided at locations where the inertia of the moving body is a problem.

For example, even if an emergency stop is applied, depending on the load, the movement of the robot arm cannot be stopped immediately due to the inertia of the robot arm, and the distance the robot arm will slide until it stops becomes long. It has been added.

(D. Problems to be Solved by the Invention °) [Figure 4] By the way, the conventional emergency stop method using a robot controller does not take into account the motion state of the robot or the nature of the robot's degree of freedom.

In other words, even though the robot arm is moving at high speed when attempting to apply an emergency stop, if you suddenly release the servo control, short circuit the regenerative resistor, or apply the mechanical brake, an instantaneous load will be placed on the actuator. If torque is generated and exceeds an allowable range, problems such as damage to the actuator and positional deviation due to tooth skipping of the reducer may occur.

This inconvenience is due to the fact that conventional devices do not have a stop control method to reduce the instantaneous load torque applied to the actuator.

Furthermore, an example of the inconvenience caused by not considering the characteristics of the load regarding the degree of freedom is as shown in FIG. 4.

The figure shows the stocking operation of pallets b by the orthogonal robot a.

C is a stocker for storing pallet b, and the area where pallet b is stored is divided into several parts by partition plates d, d, etc., and the orthogonal robot a carries pallet b from a location not shown. It is then stored in a predetermined location within the stocker C.

This robot a is supported by a base shaft f so that its arm e can move in the vertical direction (indicated by arrow A).

A hand part g provided at the tip of the arm e is attached to the arm e in a horizontally movable state, and a pallet b is placed on this hand part g and carried. ing.

By the way, since the degrees of freedom of robot a include the degree of freedom in which the direction of movement is along the direction of gravity, the emergency stop procedure can be performed using other degrees of freedom (that is, degrees of freedom in which the direction of movement does not match the direction of gravity). ) cannot be treated in the same way as the axis related to

This is because when arm e is moved along the direction of gravity, the gravity due to arm e's own weight is always acting as an external force, so a mechanical brake is applied to the car to stop arm e from moving. Depending on the timing when the brake is applied, vibration may occur in arm e.
If the impact at this time is large, the parts arranged on pallet b will be scattered, or in the worst case, pallet b will come into contact with the partition plate d of stocker C, causing the impact on the already stocked pallets. This causes the inconvenience that the information is not transmitted properly.

Furthermore, in the conventional emergency stop procedure, the stop process does not take into account the load effect due to inertia etc. for each degree of freedom, and the state of motion of the axis when an emergency stop is applied. There was a problem that the behavior was different and the attitude after stopping was completely unpredictable.

(E. Means for Solving the Problems) Therefore, in order to solve the above-mentioned problems, the emergency stop device of the robot numerical control device of the present invention stops the movement of each axis that makes up the robot during an emergency stop of the robot. This is an emergency stop device for a robot numerical control device, which is equipped with a command means for giving a command to a stop means for a robot, and includes a characteristic storage means for pre-holding information regarding load characteristics regarding the robot's degrees of freedom, and A motion state detection means for detecting a motion state and a stop procedure storage means for storing in advance control commands for a plurality of emergency stop procedures are provided, and at the time of an emergency stop, the command means receives information regarding the characteristics of each degree of freedom from the characteristic storage means. and information regarding the motion state of each axis from the motion state detection means, reads an emergency stop procedure corresponding to this information from the stop procedure storage means, and sends a signal to the stop means in accordance with the content of the control command regarding the procedure. The stopping process is performed for each degree of freedom of the robot.

Therefore, according to the present invention, the command means can read the emergency stop procedure according to the characteristics and movement state regarding the degree of freedom of the robot from the stop procedure storage means and perform an appropriate stop process for each degree of freedom. Therefore, there are disadvantages such as excessive load torque on the axis, decreased positional accuracy due to tooth skipping of the reducer, and vibrations during stopping due to various types of stopping processing for each axis. This also eliminates the inconvenience of the robot having an unexpected posture after stopping.

(F. Embodiment) [FIGS. 1 to 3] Details of the emergency stop device of the robot numerical control device of the present invention will be described below according to the illustrated embodiment.

(a, configuration) [*1 Figure 1 is a robot controller, which is provided to control each degree of freedom of the robot. In addition to supplying power to the motor and controlling it, the power is also cut off in case of an emergency.

In the figure, a system consisting of a motor 3 and a mechanical brake 4 is shown as the actuator 2.

Regarding power, power is supplied to the motor 3 via the robot controller 1, and the rotation of the motor 3 is controlled, and operation/non-operation of the mechanical brake 4 is controlled by commands from the robot controller 1. It has become.

A position sensor 5 and a torque sensor 6 are provided as detectors, and their detection signals are sent to the robot controller l as a feedback signal.

The robot controller 1 includes a power control system that controls supply/cutoff of power to the actuator 2, and a power control system that controls the supply/cutoff of power to the actuator 2.
First, the power control system will be explained first.

Reference numeral 7 denotes a power cutoff section, which is provided to determine whether or not to supply power from the power source to the actuator 2.

When power supply to the motor 3 is permitted in the power cutoff section 7, power is supplied to the motor 3 via the power control section 8 and the regenerative resistor short circuit 9 at the subsequent stage.

The operation control system includes a command value generation section 10 and its storage section 1085.
It consists of a control procedure storage section 11 and a servo control section 12.

The command value generation section 10 sends a predetermined command signal to the servo control section 12 when the robot's operation is normal and controlled in a safe state. In response to this command, the servo control unit a 12 sends control signals to the power control unit 8 in accordance with the signals from the position sensor 5 and torque sensor 6, so that software servo control of the motor 3 is performed. is realized.

Then, the command value generating unit IO receives an emergency stop command,
Emergency stop processing is performed when there is some abnormality in the operating state of the robot and an error signal is detected, and a predetermined emergency stop procedure is read out from the control procedure storage unit 11 and followed. Emergency stop processing is performed for each degree of freedom of the robot.

In other words, the command value generation section 10 is its storage section! Information indicating the degree of freedom number assigned to each degree of freedom and its characteristics written in advance in Oa, and the current control status obtained from the servo control unit 12! 14 (that is, whether it is in a stopped state or a moving state, its speed, etc.), and further information regarding the external environment (hereinafter referred to as "external environment information", and specific examples thereof will be described later). The emergency stop procedure is read from the control procedure storage section 11. Then, according to the procedure, the command value generation section 10 sends a signal to the power cutoff section 7 to cut off the power supply, or sends a command signal to the servo control section 12 to control the operation and operation timing of the mechanical brake 4. It also controls the operation and timing of the regenerative resistor short circuit 9, and performs servo control (position servo, torque servo, etc.) of the motor 3 as necessary during the transition period until it stops. It has become.

(b. Example of emergency stop procedure) [Figure 2] Figure 2 is a conceptual time chart showing some examples of the emergency stop procedure in the robot controller 1 described above. indicates the input state of an emergency stop command; if there is a command, a logical value of "1" is given, and if there is no command, a logical value of "0" is given. Further, "S," indicates a cutoff state by the power cutoff section 7, and the logical value for the power cutoff state is "1" and the logic value for the power supply state is "0". Further, "S," indicates a short circuit state due to the regenerative resistor short circuit 9, and the logic value for the short circuit state is "1", and the logic value for the non-short circuit state is "O".

"S4" indicates an operation command for the mechanical brake 4, and when there is an operation command to the brake, a logical value of "1" is given, and when there is no operation command, a logical value of "0" is given.

Regarding the level of logical values, the level of "1" in the time chart is high, and the level of "0" is low.

'SC12J shows the control content by the servo control unit 12, and whether or not a predetermined servo control is being performed is indicated by whether the chart has width in the vertical direction. The type is also listed.

(b-1, Procedure (A)) FIG. 2 (A) shows the emergency stop procedure (A) performed on an axis that has already stopped when an emergency stop is to be applied.

In this case, even if the mechanical brake 4 is applied instantaneously, excessive torque will not be applied to the motor 3, so in order to complete the position control in the shortest possible time and lock the shaft with the brake, input an emergency stop command ( SE='
1), the power is immediately cut off, the regenerative resistor is shorted, the brake is activated, and the position servo control is canceled.

(b-2, Procedure (B)) Figure 2 (B) shows the emergency stop procedure (B) performed on the axis that is moving at maximum speed when attempting to apply an emergency stop.
It shows.

In this case, if you perform the stop process as in step (A), an excessive load torque will be applied to the motor 3 and the devices driven by it (including reduction gears, etc.). As shown in the figure, when there is a human power to command an emergency stop, the previous position servo control is switched to torque servo control.

That is, the servo control unit 12 applies torque servo according to the feedback signal from the torque sensor 6, forming a torque control system.

Furthermore, when an emergency stop is applied, power is cut off.

After the power is cut off, the drive of the motor 3 is controlled using the charge in the capacitor of the motor 3 as a backup power source.

While the torque servo is applied, the torque command value is controlled to be within the permissible range so that the load torque does not exceed the permissible range, and after a predetermined time the regenerative resistor is shorted and the mechanical brake 4 is activated. .

(b = 3. Procedure (C)) Figure 2 (C) is an example of an emergency stop procedure that takes into account the characteristics of the degrees of freedom. It shows.

When an axis with such degrees of freedom is in motion, the procedure (B
), it is common for a shock to occur when stopping as explained in FIG. 4, so to avoid this, the following procedure is taken.

That is, even when an emergency stop is applied, the position servo that has been applied previously is continued for a while, and control is performed to maintain the current position for a while.

As shown in the figure, when an emergency stop is applied, the power is cut off and the brakes are applied, but until the shaft is locked by the mechanical brake 4 and stopped, position servo control is performed (the target value of speed is set to zero). (You may also apply a speed servo.)

Thereafter, the regenerative resistor is short-circuited.

(b-4, Procedure (D)) Figure 2 (D) shows the situation when the command value generation unit 10 receives external environment information and stops the axis moving at high speed in the shortest possible time. There is.

Here, the external environment information refers to information sent to the command value generation unit 10 from a detection means for detecting a dangerous situation such as, for example, a human intruding into the robot's movable range.

Detection means include, for example, a camera to monitor the robot and its surroundings, and a door attached to a safety fence that prevents people from easily entering the work area while the robot is operating. Examples include switches for detecting opening/closing.

In the figure, 'SEXJ' indicates this external environment information and the emergency stop command generated accordingly, and has a logical value of '1'.
indicates that there is a habit of intrusion by people, and the logical value is "0".
indicates that there is no such danger.

When a person enters the robot's movable range while the robot is operating, or there is a risk of a person entering, the command value generator 10 receives external environment information from the detection means, stops servo control, and immediately By cutting off the power, short-circuiting the regenerative resistor, and activating the mechanical brake 4, emergency stop processing is performed in the shortest possible time to minimize harm to people.

(c. Emergency stop processing) [Fig. 3] Next, the flow of the emergency stop processing by the robot controller 1 will be explained according to the flowchart shown in Fig. 3.

a) "r Start" Processing by the command value generating section 10 is started when an emergency is notified by inputting an emergency stop command or external environment information, or when an error is detected.

b) Obtain information regarding r-degree-of-freedom numbers and characteristics of degrees of freedom.

” The command value generation unit 10 retrieves from the storage unit 10a the degree of freedom number assigned in advance to each axis of the robot and information indicating the characteristics of the degree of freedom number.

For example, as shown in Table 1 below, for the degree of freedom number "1", there is no additional information indicating the characteristics of the degree of freedom;
2" has the characteristic that the direction of movement of the axis coincides with the direction of gravity.

Table 1 c) Obtain information regarding the control state of the r-axis. The command value generation section 10 obtains information regarding the current control state of the axis from the servo control section 12, and learns its motion state, that is, whether it is stopped or moving, and the speed at that time.

Then proceed to the next step d).

d) r Obtain external environment information. ” The command value generation unit 1o obtains external environment information from the above-mentioned detection means (surveillance camera, detection switch, etc.) and learns whether or not there is a habit of intrusion of people or the like into the work area of the robot.

If there is a habit of intrusion by people, priority is given to step (D).

Then proceed to the next step e).

e) Read information regarding the stop procedure from the r control procedure storage unit. ” That is, the command value generation unit 10 retrieves information regarding the stop procedure corresponding to the information obtained in steps b) to d) from the control procedure storage unit 11.

For example, as shown in Table 1, when the axis with degree of freedom number 1 is stopped, procedure (A) or (D) is selected depending on the external environment information. (In this case, step (A) and (
In step D), the same stop processing is performed in actual purchase, so if you consider the external environment information as part of the emergency stop input, procedure (A)
) may always be used. ) In addition, if the axis with degree of freedom number 1 is moving, procedure (B) or (D) is selected depending on whether there is a risk of people entering the robot's movable range. Ru.

For the axis with degree of freedom number 2, an emergency measure is selected according to the characteristics of the degree of freedom.

That is, if the axis is stopped, step (A) or (D)
is selected, and when the axis is moving, procedure (C) is selected if there is no risk of intrusion of people within the robot's movable range, and procedure (D) is selected if the robot is accustomed to intrusion. Ru.

Then, the command value generation unit 10 sequentially analyzes the contents of the individual control commands constituting the selected stop procedure, and in step f
).

f) "Is it a command to operate the mechanical brake?" A question is asked as to whether the control command is a command to operate the mechanical brake 4, and if it is a command to operate, proceed to step g), otherwise proceed to step h).

g) "Activate the mechanical brake." The command value generation section 10 sends a signal for operating the mechanical brake 4 to the servo control section 12.

Then proceed to step h).

h) "Is it a regenerative resistor short circuit command?" A question is asked as to whether the control command is a regenerative resistor short circuit command.
If so, proceed to step i), otherwise proceed to step j).

i) "Short-circuit the regenerative resistor." A signal from the command value generator 10 is sent to the regenerative resistor short-circuit circuit 9 via the servo controller 12, and the regenerative resistor of the motor 3 is short-circuited.

Then proceed to step j).

j) "Is it a power cutoff command?" It is asked whether the control command is a power cutoff command or not. If so, proceed to step k); otherwise, proceed to step l).

k) "Cut off the power." The power supply to the motor 3 is cut off by a signal sent from the command value generation section 10 to the power cutoff section 7.

Then, proceed to step J2).

A) "Perform designated control." This is performed if there is a control command other than those related to steps g), i), and k) during an emergency stop.

For example, in step (B) described above, control is transferred from the position servo to torque servo, and in step (C), the position servo continues for a while after an emergency stop is applied, and then servo control is canceled. will be done.

m) "Has the control procedure been completed?" It is asked whether the series of control procedures have been completed (that is, whether the control command is a termination command), and if it has not been completed, the process returns to step e).

Then, when all the emergency stop procedures for each axis of the robot are completed, the emergency stop operation ends.

(G. Effects of the Invention) As is clear from the above description, the first aspect of the present invention is to provide a stop means for stopping the motion of each axis constituting the robot during an emergency stop of the robot. This is an emergency stop device for a robot numerical control device, which is equipped with a command means for issuing commands based on the robot's degree of freedom, and includes a characteristic storage means for pre-holding information regarding load characteristics regarding the degree of freedom of the robot, and a movement state for detecting the motion state of each axis. A state detection means and a stop procedure storage means for storing control commands for a plurality of emergency stop procedures in advance are provided, and at the time of an emergency stop, the command means receives information about the characteristics of each degree of freedom from the characteristic storage means and detects the motion state. Upon receiving information about the motion status of each axis from the means, an emergency stop procedure corresponding to this information is read from the stop procedure storage means, and a signal is sent to the stop means according to the content of the control command regarding the procedure to stop the robot from moving freely. The feature is that the stop processing is performed every time.

Therefore, according to this, the command means can read the emergency stop procedure according to the characteristics and movement state regarding the robot's degrees of freedom from the stop procedure storage means and perform an appropriate stop process for each degree of freedom. Disadvantages caused by performing various types of stopping processing on the shaft, such as excessive load torque on the shaft, decreased positional accuracy due to tooth skipping of the reducer, etc., and vibrations when stopping. This also eliminates the inconvenience of the robot having an unexpected posture after stopping.

Further, the second aspect of the present invention is further provided with a situation detection means for detecting the motion state of the robot including its surrounding situation, and in the event of an emergency stop, the command means uses information from the characteristic storage means and the situation detection means. The present invention is characterized in that an emergency stop procedure corresponding to the information regarding the motion state of the robot and the surrounding situation from the means is read out from the stop procedure storage means.

Therefore, according to this, it is possible to perform a wide range of stopping processing including information regarding the surrounding situation of the robot.

For example, if there is a risk that a person may enter the robot's movable range, the command means receives information from the situation detection means and reads out an emergency stop procedure for dealing with this emergency from the stop procedure storage means. Therefore, it is possible to perform a stop process that prioritizes human protection over the adverse effects on the robot due to overload during an emergency stop.

[Brief explanation of drawings]

1 to 3 show an example of the implementation of the emergency stop device of the robot numerical control device of the present invention, FIG. 1 is a block diagram showing the configuration, and FIG. 2 is a conceptual diagram showing some of the emergency stop procedures. This is a time chart diagram, in which (A) shows the procedure for a stopped glaze, (B) shows a procedure for a moving axis, and (C) shows the procedure for a moving axis.
is the procedure for the axis whose direction of movement coincides with the direction of gravity, (D
) indicate the procedures according to the external environment information, and the third
The figure is a flowchart showing the flow of emergency stop processing.
The figure is a schematic diagram for explaining conventional problems. Explanation of symbols 1...Robot numerical control device, 4, F, 9...Stopping means, 10...Command means, 10a...Characteristics storage means, ・Stopping procedure storage means, ・Movement state detection means A schematic diagram to explain the problem

Claims (2)

[Claims] (1) An emergency stop device for a robot numerical control device, which is equipped with a command means for giving a command to a stop means to stop the motion of each axis that makes up the robot during an emergency stop of the robot, and which provides freedom for the robot. a characteristic storage means for pre-holding information regarding load characteristics in terms of speed; a motion state detection means for detecting the motion state of each axis; and a stop procedure storage means for pre-storing control commands for a plurality of emergency stop procedures. and when an emergency stop occurs, the command means receives information regarding the characteristics of each degree of freedom from the characteristic storage means and information regarding the motion state of each axis from the motion state detection means, and stops an emergency stop procedure corresponding to these information. An emergency stop device for a robot numerical control device, characterized in that a signal is read from a procedure storage means and sent to a stop means according to the content of a control command related to the procedure to perform a stop process for each degree of freedom of the robot. (2) A situation detection means is provided to detect the movement state of the robot including its surrounding situation, and in the event of an emergency stop, the command means uses information from the characteristic storage means,
2. The emergency stop device for a robot numerical control device according to claim 1, wherein the emergency stop procedure corresponding to the information regarding the movement state of the robot and the surrounding situation from the situation detection means is read out from the stop procedure storage means.