JPH06297366A - Industrial robot - Google Patents

Abstract

PURPOSE:To economize energy by cutting off or reducing a motor current, simultaneously with the operation of a brake through the cutting-off of the current-currying to the brake, in an input waiting or time lapse waiting state. CONSTITUTION:The teaching information inputted from a programming unit 4 is inputted into a control part 13 through a play-back console 3, and the contents which is previously taught is outputted into a servoamplifier 10, and a motor 5 is driven. Further, brake is released by putting a brake device 8 into electric conduction through a brake circuit 12, and the brake is operated when the electric conduction is cut off. In this case, in the control part 13, the stop time point of a robot body and the period (stop period) up to the shift starting time point succeeding the stop time point are detected successively on the basis of the teaching information, and when the stop period is detected, the electric conduction for the brake device 8 is cut off, and at the same time, the motor electric current is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial robot using an electric servomotor for driving a manipulator,
In particular, the present invention relates to an industrial robot suitable for a teaching / playback type robot apparatus.

[0002]

2. Description of the Related Art Industrial robots, especially teaching and
In playback type industrial robots, manipulators
(Robot body) Generally, an electric servo motor is used as a power source for driving, and this servo motor is usually equipped with an electromagnetic release type brake, a so-called off brake type brake. And, in the conventional robot apparatus, the braking force by this brake causes the robot to stop its operation and the current supplied to the servo motor is cut off, that is, the posture is maintained at the time of so-called motor current cutoff. It was used only for the purpose, and during playback, even if the robot was stopped, the brake was still energized and the braking force was kept from working.

To explain this with reference to FIG. 4, in a teaching / playback system robot, as shown in FIG. 4 (a), a servomotor (hereinafter simply referred to as a motor) of a certain joint (movable axis) of the manipulator. Assuming that during rotation, the robot stops at a teach point (teaching point) at a certain time T ₁ after time 0 and starts to rotate again at a time T ₂ after a predetermined elapsed time waiting period T _W , the same is true. As shown in FIG. 7B, the motor current is kept supplied during this period T _W as well, and similarly, the brake current is continuously supplied as shown in FIG. The brake is not operated even during the period T _W when the manipulator is stopped, and the posture of the manipulator at this time is maintained only by the stop torque generated by the stop holding current supplied to the motor. The It was

[0004]

It cannot be said that the above-mentioned prior art gives sufficient consideration to the energy saving and the power saving of the robot device, and the power consumption increases, and the heat generation amount of the motor and the brake is reduced. There has been a problem that the increase in temperature causes a remarkable increase in temperature and an increase in operating cost.

That is, in the teaching / playback type robot, when trying to execute a certain work in a certain work area, there is generally a considerable period of waiting for control input and waiting for elapsed time. However, in the conventional technology, since power is continuously supplied to both the motor and the brake during this waiting period, power consumption increases.

In particular, in the case of a motor with a built-in brake, an off-brake type brake is generally used, which causes a rise in the temperature of the motor, which is an obstacle to power saving and motor size reduction. Was becoming.

In view of the recent energy situation, it is an object of the present invention to provide an industrial robot which is more energy-saving and power-saving as a part of measures for preventing global warming.

[0008]

The above-mentioned object is to provide at least one of a stop period detecting means for detecting a period between a stop time of the manipulator and a movement start time subsequent thereto, and at least one of currents supplied to the manipulator driving servomotor. And a current control means for interrupting the current supplied to the electromagnetic release type brake device for maintaining the attitude of the manipulator,
This is achieved by operating the current control means within the period detected by the stop period detection means.

This will be specifically described in accordance with the embodiment as follows.

According to the present invention, when an industrial robot tries to perform a certain work in a certain work area, generally, there is a considerable amount of time waiting for input and waiting for elapsed time. Energy is saved by cutting off the power supply to operate the brake and at the same time cut off or reduce the motor current.

On the other hand, the brake has a property that the position is displaced during operation, regardless of the degree. Therefore, when the current of the brake is cut off and the current of the motor is cut off or reduced, the manipulator is initially operated. Since it may stop at the target position, the manipulator position is changed when the motor is cut off by setting a step in the target positioning range in the input waiting state and the waiting state for the elapsed time. If there is a problem with deviation, the motor current is not cut off or reduced.

In the case of waiting for too short elapsed time and waiting for input, in order to prevent frequent brake operation, opening, and energization / interruption of motor current, brake current is applied,
The timing of turning off and the timing of energization / interruption of the motor current can be changed so that actuation of the brake, opening and energization / interruption of the motor current shorter than a certain period of time can be prevented.

Next, in the above-mentioned case, since it is assumed that the motor current is used in a state where it largely deviates from the motor current set in advance, a temperature detector for preventing the motor from burning is installed in the motor. It is built in, and when it detects that the temperature detector exceeds the allowable temperature of the motor, the operation is interrupted or stopped.

Further, according to the present invention, since the brake is frequently operated during the operation of the robot, the current of the brake is turned on and off gradually and from a standpoint of extending the life of the brake and preventing noise. The brake life and environment are not adversely affected.

[0015]

The stop period detection means and the current control means interrupt the current of the motor and the brake each time the manipulator is operating by playback or the like, waiting for elapsed time, and waiting for input each time. Work to reduce. In an industrial robot, when trying to perform a certain work in a certain work area, there is generally a considerable amount of time waiting for input and waiting for elapsed time. Therefore, by cutting off the current during this period, the power consumption can be sufficiently reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The industrial robot according to the present invention will be described below in detail with reference to the illustrated embodiments. First, FIG.
Shows an overall configuration of a robot apparatus to which an embodiment of the present invention is applied. Here, as an example, the upper arm 9
And a robot apparatus using an articulated robot body (manipulator) 1 having a front arm 15 is shown. Further, a control panel 2 connected to the robot body 1 and a control panel 2 connected to the control panel 2 are shown. A playback console 3 and a programming unit 4 connected to this playback console 3 are respectively shown.

FIG. 1 is a detailed configuration diagram showing the drive system of the robot body 1 by taking the upper arm 9 as an example. It goes without saying that other arms, for example, the front 15 and the like have the same configuration. Nor. In FIG. 1, 5 is a motor
(Servo motor), 6 is an off-brake type braking device, 7 is a position detector, 8 is a speed reducer, 10 is a servo amplifier, 11 is a motor shaft, 12 is a brake circuit, 13 is a control unit, and 14 is temperature detection. It is a vessel.

First, the arm 9 is connected to the motor shaft 11 via the speed reducer 8 and is swingably driven by the rotation of the motor 5. The brake device 6 is built in the motor 5,
Thereby, the rotation of the motor shaft 11 is fixed and the posture is maintained. The position detector 7 detects a position according to the rotation of the motor shaft 11, and the servo amplifier 10 controls the motor current according to the detection result of this position.

The teaching information is input from the programming unit 4 and the control unit 13 via the playback console 3. Then, the control unit 13 inputs the content taught in advance based on the information from the playback console 3 to the servo amplifier 10 to drive the motor 5. on the other hand,
The brake device 8 is controlled by the brake circuit 12 on the basis of a command from the control unit 13, and releases the braking force when a current is supplied, and operates the braking force when the current is cut off.

The control unit 13 is built in the control panel 2 and includes a microcomputer, which executes predetermined processes in accordance with various programs installed therein to execute various processes required for robot control. It is configured to carry out.

Further, the control section 13 is based on the teaching information input from the playback console 3 as a part of the processing means by the microcomputer provided therein, and based on the teaching information, the robot main body 1 is stopped and the subsequent movement is started. A stop period detecting means for sequentially detecting the period up to the time point, and a current control means for interrupting at least a part of the current supplied to the motor 5 and the current supplied to the brake device 6 are provided. In this way, the control shown in FIG. 3 is executed.

FIG. 3 shows the rotational speed of the motor 5 at a certain teach point of the robot body 1, the current of the motor 5, and the current of the brake device 6, respectively. At the time of 0, the robot body 1
Is moving from the teach point before this certain teach point, the rotation speed of the motor 5 is a constant speed before time 0, and then decelerates to reach the teach point at time T ₁ .
Stop there (rotation speed 0). And this teach point
At the (position), waiting for a predetermined input or waiting for an elapsed time until time T ₄ , the rotation speed of the motor 5 is 0 during this period T _W.

Then, the robot body 1 starts moving again at time T _{4 and} moves toward the next teach point, so that the rotation speed of the motor 5 accelerates again at time T _{4 and} reaches a predetermined constant value.

At this time, the electric current of the motor 5 has a constant value because it has only a current value corresponding to the holding torque due to the moment applied to the arm 9 since the motor 5 is stopped after the time T _1. Become.

Next, during this period, if the control section 13 detects that the period T _W from the time T _{1 to} the time T ₄ has been detected by the stop period detecting means provided thereto, the control unit 13 also similarly The control of the currents of the motor 5 and the braking device 6 by the current control means provided to the control unit 13 is started, and first, the current of the braking device 6 is started to be reduced at time T _{1, and} at a predetermined time point T ₂ thereafter. 0 to shut off. And in parallel with this, this predetermined time T
_{At 2} , the current of the motor 5 is cut off.

That is, the current of the brake device 6 is the time T
Up to _1, a constant value for keeping the brake open is maintained, but it starts to decrease at time T ₁ to activate the brake and becomes 0 at time T ₂ , where the braking force is fully activated. As a result, from this time T ₂ , the braking force by the braking device 6 starts to be completely applied, and the electric current of the motor 5 is made zero after this time.

What is important here is that the current of the motor 5 is not set to 0 and a current corresponding to the moment torque is supplied until the time T ₂ when the brake is fully activated. There is a risk that 9 will fall due to gravity.

Further, stop period detecting means in this control unit 13, since it is possible to know the time T ₄ the period T _W is completed by the teaching data in advance, thereby exercising current control means, to the time T ₄ At a time point T ₃ before the above, the current of the motor 5 is first raised from 0 until then to a current value corresponding to the holding torque due to the moment applied to the arm 9. Then, at the same time, starts the power from time T ₃ to the brake device 6 is to increase up to the current required to completely open the brake at time T _4. As a result, the current of the motor 5 has a constant value from time T ₃ until the brake begins to slacken and is completely released until time T ₄ , and thereafter, the robot body 1 is required to move to the next teach point. It is controlled by the current value.

Therefore, according to this embodiment, within the period T _W from the time T ₁ to the time T ₄ waiting for the elapsed time, the time T
_{From 2} to T ₃ , the motor current and the brake current can be set to 0 without changing the posture control of the robot body 1, power consumption can be reduced, and energy saving can be promoted. .

In particular, in such a robot, when the robot body 2 tries to perform a certain work in a certain work area, generally, there is a considerable proportion of time waiting for input and waiting for elapsed time. Therefore, according to this embodiment, a sufficiently large reduction in power consumption can be easily obtained, and a large energy saving can be surely obtained.

Further, as a result, the continuous operation time of the motor 5 is shortened, so that the rating can be lowered, the motor having a small capacity can be used, and the size and the weight can be reduced. According to an embodiment, the rate of decrease in the capacity of the motor obtained at this time is 80% to 70%.
We have also achieved a significant reduction in size and weight.

By the way, in this embodiment, the motor 5 is controlled by excluding the duty set in advance,
Large motor current may flow. In this embodiment, however, the temperature detector 14 is built in the motor 5, so that the controller 13 monitors the temperature of the motor 5 and stops or interrupts the work when the temperature exceeds a certain temperature. Is configured to be able to. Therefore, according to this embodiment, it is possible to prevent the possibility of an abnormality from occurring and maintain high reliability.

Further, in the above embodiment, as is apparent from FIG. 3, the current of the braking device 6 is not immediately interrupted or the maximum value current is supplied at time T ₁ and time T ₄ , respectively. The brake circuit 12 is configured to temporarily increase and decrease over time from time T ₁ to T ₂ and time T ₃ to T ₄ .

Therefore, according to this embodiment, the impact on the mechanical portion when the brake device 6 is opened and when it is activated can be softened, and noise can be reduced and the life of the brake can be extended.

Next, another embodiment of the present invention will be described. Since the brake device 6 is basically a kind of friction brake, its structure has some property that the positioning of the motor shaft 11 is displaced when the energization is cut off and the braking force is activated. On the other hand, in the control of the motor 5, the width of the positioning range is determined by the servo constant set in the servo amplifier 10.

Therefore, in another embodiment of the present invention, the control unit 13 is provided with means for detecting the width of the positioning range of the servo constant set for the control of the motor 5, and the width of the detected positioning range is The current control means is activated only when a predetermined value is exceeded. Here, the width of the positioning range of the servo constant is related to the positioning accuracy at the teach point of the robot body 1, and the narrower the width, the higher the accuracy.

Therefore, according to this embodiment, when the positioning accuracy of the robot is set to a high level and the occurrence of an error by the braking device 6 may become a problem, the motor 5 is automatically operated by the current control means. Since the current cutoff control of the brake device 6 is stopped, the positioning accuracy is prevented from being lowered, but it can be reliably prevented, and the predetermined accuracy can be always maintained.

Next, in the above embodiment, the power supply to the motor 5 and the brake device 6 is cut off each time the robot reaches the teach position. Therefore, depending on the work contents taught by the robot, the frequency is considerably increased. Energization and interruption of the motor current, and operation and release of the brake are repeated.

Therefore, the control unit 13 is provided with a judging means for checking the length of the period detected by the above-mentioned stop period detecting means so that the current controlling means is activated only when the judged period exceeds a predetermined value. You may comprise. Specifically, an offset is provided at each of the time when the robot body 1 reaches the teach point, the time when the brake current starts to be reduced, and the time when the motor current is switched from the interruption to the energization, and the offset can be changed. However, when waiting for an elapsed time shorter than a certain time and waiting for input, the motor 5
It is configured such that the current is not passed through or cut off, and the brake device 6 is neither activated nor released.

According to this embodiment, the frequency of energization / interruption of the electric current of the motor 5 and the operation / release of the brake device 6 can be arbitrarily adjusted according to the contents of the teaching and the like, and power saving can be achieved. Appropriate operation can be obtained while trying.

As is clear from the above embodiment,
Embodiments of the present invention include the following.

In the industrial robot according to the above-mentioned claim 1, the temperature detector is built in the motor, and when the temperature of the motor exceeds a certain temperature, the operation is stopped or interrupted. And industrial robots.

The industrial robot according to any one of claims 1, 2, and 3, characterized in that the braking current is intermittently increased and decreased.

[0044]

According to the present invention, the power consumption of the servo motor and the brake device can be greatly reduced, so that the power saving and the robot device can be made compact, and the energy saving of the production equipment can be sufficiently achieved. .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an industrial robot according to the present invention.

FIG. 2 is an overall configuration diagram showing an example of a robot apparatus to which an embodiment of the present invention is applied.

FIG. 3 is a timing chart for explaining a control operation of a motor speed, a motor current and a brake current according to an embodiment of the present invention.

FIG. 4 is a timing chart for explaining a control operation of a motor speed, a motor current and a brake current in a conventional example of a robot apparatus.

[Explanation of symbols]

 1 Robot main body (manipulator) 2 Control panel 3 Playback console 4 Programming unit 5 Motor (servo motor) 6 Brake device 7 Position detector 8 Speed reducer 9 Upper arm 10 Servo amplifier 11 Motor shaft 12 Brake circuit 13 Control part 14 Temperature detection Vessel 15 front arm

Claims (3)

[Claims] 1. In an industrial robot of a system in which the manipulator is moved and stopped sequentially by a series of preset operation commands, a period between the manipulator stop time and the subsequent movement start time. Stop period detecting means for sequentially detecting the current, at least a part of the current supplied to the manipulator driving servomotor and the current for interrupting the current supplied to the electromagnetic opening type brake device for maintaining the attitude of the manipulator. A control means is provided, and the current control means is configured to operate within the period detected by the stop period detection means. 2. The invention according to claim 1, further comprising means for detecting the width of the positioning range of the servo constant set for the control of the servo motor, and only when the width of the detected positioning range exceeds a predetermined value. An industrial robot, characterized in that the current control means is activated. 3. The invention according to claim 1, further comprising determination means for checking the length of the period detected by the stop period detection means, and the current control means is operated only when the determined period exceeds a predetermined value. An industrial robot characterized by being configured as described above.