Electricity: motive power systems – Positional servo systems – Program- or pattern-controlled systems
Patent
1982-05-13
1984-07-03
Dobeck, B.
Electricity: motive power systems
Positional servo systems
Program- or pattern-controlled systems
318590, 318681, G05B 1942
Patent
active
044581882
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to an industrial robot having a function for controlling a current of a motor for driving.
2. Background Art
A direct current electric motor has heretofore been used for driving the shafts of an industrial robot, and a control circuit, as shown in FIG. 1, has been used for controlling the driving of the direct current electric motor.
The control circuit shown in FIG. 1, is operated as follows.
A position command input 11 is given, and in an adder 12, a difference between this position command input 11 and a position feedback signal 18 from a pulse coder 17 connected to an electric motor 16 is calculated and this difference is set at an error register 13. The set value is converted to an analog value by a digital-analog converter (DA converter) 19 and is supplied as a speed command signal to one input of a speed-controlling amplifier circuit 15. The position feedback signal 18 from the pulse coder 17 is converted to a voltage signal by a frequency-voltage converter (VF converter) 14 and this voltage signal is supplied as a speed feedback signal to the other output of the speed-controlling amplifier circuit 15. Driving of the electric motor 16 is controlled by the output of the speed-controlling amplifier circuit 15.
In an industrial robot comprising the above-mentioned control circuit, however, it is impossible to press an article to be held against another article under a certain output torque. For example, in the case where an article to be held is held only by the position control in a desirable fixed state on a chuck of a machine tool, for example, a lathe, it is difficult to hold the article on the chuck in a desirable fixed state. Accordingly, in an industrial robot having the above-mentioned circuit, though position control characteristics are satisfactory, the operation of pressing an article to be held against another article under a certain output torque cannot be performed.
The present invention proposes an industrial robot in which this problem of the conventional technique is solved.
DISCLOSURE OF THE INVENTION
It is a primary object of the present invention to provide an industrial robot, in which, in order to solve the above problem of the conventional technique, control of the position is performed by a position command and when an article to be held arrives at a predetermined position, the position control is switched over to the current control by a switching command signal, whereby it is made possible to press the article to be held against another article and the reliability of the operation of the industrial robot can be increased.
In accordance with one aspect of the present invention, there is provided an industrial robot having a function for controlling a current of a motor for driving, which comprises a circuit for summing a plurality of input signals to which input signals of speed command, speed feedback, current command and current feedback are supplied, a switching circuit for selectively switching the input of speed command to the inputs of current command and current feedback by a switching command signal and an operational amplifier to which said switched signal is supplied.
In accordance with another aspect of the present invention, there is provided an industrial robot having a function for controlling a current of a motor for driving, which comprises a robot control device, a switching circuit including a first switch which receives an output of the robot control device through a register and a digital-analog converter, is inserted in a circuit for input of the speed command and is closed at the position control while it is opened at the current control and a second switch which is inserted in a circuit for input of the current command and input of the current feedback and is opened at the position control while it is closed at the current control, a circuit for summing a plurality of input signals which receives the output of the switching circuit and to which inputs of speed command, speed feedback, curren
REFERENCES:
patent: 3934186 (1976-01-01), Hayakawa
patent: 3990020 (1975-06-01), Porter
patent: 4011437 (1977-03-01), Hohn
patent: 4206394 (1980-06-01), Flandorfer
patent: 4297624 (1981-10-01), Komiya
patent: 4300080 (1981-11-01), Lee
patent: 4348623 (1982-09-01), Kobayashi et al.
patent: 4373150 (1983-02-01), Ritter
Inaba Hajimu
Miyashita Hideo
Otsuka Shoichi
Dobeck B.
Fujitsu Fanuc Limited
LandOfFree
Industrial robot having a function for controlling a current of does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Industrial robot having a function for controlling a current of , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Industrial robot having a function for controlling a current of will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1632319