Electricity: motive power systems – Positional servo systems – Program- or pattern-controlled systems
Reexamination Certificate
1999-06-21
2001-01-30
Nappi, Robert E. (Department: 2837)
Electricity: motive power systems
Positional servo systems
Program- or pattern-controlled systems
C318S560000
Reexamination Certificate
active
06181096
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a system to control an industrial robot (hereinafter referred to simply as a “robot”).
(2) Description of the Prior Art
A robot normally comprises a robot arm into which a servomotor has been incorporated, and the said servomotor is driven by a servo-amplifier unit. The control of the robot is performed by aiving commands to the servo-amplifier unit by a controlling device.
FIG. 5
is a schematic block diagram to explain the conventional robot controt. Incidentally, in
FIG. 5
a robot in a form shown in Japanese Patent Application Laid-Open No.8-11074 specification for example is shown as an example of the conventional robot.
A controlling unit
1
controls a servo amplifier unit
2
, and, based on the control the servo amplifier unit
2
supplies a power to a servomotor
31
of a robot unit
3
. The servomotor
31
is incorporated into every robot arm
32
, and controlled by the controlling unit
1
via the servo amplifier unit
2
.
Between the controlling unit
1
and the servo amplifier unit
2
, the controlling unit
1
sends a PWM command to the servo amplifier unit
2
and obtains a current feedback value from the servo amplifier unit
2
. In addition, between the controlling unit
1
and the robot
3
, the controlling unit
1
outputs an output for an end effector to the robot
3
and inputs a servomotor speed feedback signal, a servomotor position feedback signal an end effector input signal and a robot overtravel signal from the robot
3
.
The controlling unit
1
conducts current control of a servo motor system based on the current feedback value, and speed control or position control of the servomotor system based on the servomotor speed feedback signals or the servomotor position feedback signls. In addition, by input and output signals for the end effector, control of every kind of function which the robot comprises is conducted by a robot overtravel signal whereby an over movement of the robot arm is detected.
In addition, Japanese Patent Application Laid-Open No.8-229862 discloses placing a servo amplifier in the vicinity of a motor mounted on a body of the robot for the purpose of making wiring of power cables shorter.
There is a problem in the conventional robot control systems that for the purpose of conducting transmission and reception of every kind of signal such as controlling signals, feedback signals, detection signals, et wiring between the robot and the servo amplifer unit, the servo amplifier unit and the controlling unit, and the robot and the controlling unit becomes necessary, resulting in an increase in the number of wiring.
In addition, in the case where the control unit is placed at a position far from the robot as well as the servo amplifier unit, it is necessary to extend two cables, namely the cable connecting the controlling unit and the servo amplifier unit and the cable connecting the controlling unit and the robot. In the conventional configurations, each time when a controlling unit is placed at a different position, as such a cable connecting the controlling unit and the servo amplifier unit and the cable connecting the controlling unit and the robot, it is necessary to prepare a plural kinds of cables having lengths corresponding to the position of a controlling unit to be placed.
Therefore, in the conventional robot controlling systems, there are problems in terms of the number of wirings, the number of extension cables, kinds of lengths in stock cables. An increase in the number of wiring as well as the number of kinds and units, etc. of extension cables to be deployed in advance causes an increase in costs and wirng work, resulting in a troublesome control in cables and wiring inside cables. Also there are problems in terms of appearance of covering of wiring.
In addition, in the previously described well known example (Japanese Patent Application Laid-Open No.8-229862), wiring of power cable gets shorter. Nevertheless, as concerns wiring for transmitting servomotor speed and position feedback signals, input and output signals for an end effector, and robot overtravel signals no consideration has been given to shorten wiring
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to solve the conventional problems and decrease the number of wirings, kinds of cable lengths and their quantity in the robot controlling system.
The servo controlling system of the present invention is configured to comprise a robot unit including a robot arm and a servomotor, a servo amplifier unit to drive the servomotor, and a controlling unit to control the robot arm by sending commands to the servo amplifier unit, and transmission and reception means between the controlling unit and the robot unit is conducted via the servo amplifier unit with transmit-receive means between the controlling unit and the robot unit being incorporated into transmit-receive means between the controlling unit and the servo amplifier unit and into transmit-receive means between the servo amplifier unit and the robot unit in the robot controlling system.
A command to be sent from the control unit to the robot unit as well as communication on feedback signals and detection signals to be sent from the robot unit to the controlling unit are conducted in use of transmit-receive means between the controlling unit and the servo amplifier unit as well as transmit-receive means between the servo amplifier unit and the robot unit via the servo amplifier unit.
This configuration serves to make it possible to omit transmit-receive means such as conventionally required cables, etc to attain connection between the controlling unit and the robot unit, and thus to decrease the number of cables.
In addition, to correspond to the systems different in deployment condition, such as respective deployment positions of the controlling unit, the servo amplifier unit, and the robot unit, corresponding treatments only for transmit-receive means between the controlling unit and the servo amplifier unit will do. In the cases where cables are used as the said transmit-receive means, no cables between the controlling unit and the robot unit are required, and adjustment only on cables in the controlling unit and the servo amplifier unit will do, thus making it attainable to decrease the kinds of cable lengths of cables to be prepared.
In addition the transmit-receive means between the controlling unit and the servo amplifier unit is to be configured to comprise communication means, and for the transmission and reception between the controlling unit and the robot unit, the transmission and reception between the controlling unit and the servo amplier unit is conducted through the communication means. By implementing this configuration, a plurality of kinds of transmission and reception between the controlling unit and servo amplifier unit can be performed through only a signal conductor accommodated to the communication types, without using cables each required for every type of a signal, thus maliing it possible to decrease the number of cables to be wired.
BRIEF DESCRIPTlON OF THE DRAWINGS
The foregoing and other objects and features of the invention will become apparent from the following description of preferred embodiments of the invention with reference to the accompanying drawings, in which:
FIG. 1
is a block diagram showing a configuration example of a servo controlling system of the present invention;
FIG. 2
is a block diagram in the case where communication connection is provided between the controlling unit and the servo amplifier unit of the present invention;
FIG. 3
is a schematic block diagram explaining a configuration example of each part in a controlling system of the present invention;
FIG. 4
is a block diagram explaining a configuration example of a communication controlling circuit of the present invention, and
FIG. 5
is a schematic block diagram to explain the controlling of the conventional robot
REFERENCES:
patent: 4855657 (1989-08-01), Isobe et al.
patent: 5055754 (1
Hashimoto Yoshiki
Kubo Yoshiyuki
Shimoda Yasuyuki
Duda Rina I.
Fanuc Ltd.
Nappi Robert E.
Staas & Halsey , LLP
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