Westinghouse Electric Corporation

Unimation, Inc.

Barrett L Booth

Richard J Casler, Jr

Kenneth E Daggett

Eimei M Onaga

Leonard C Vercellotti

Richard A Johnson

Norman J Bergman

Rajan C Penkar

Roy E Lancraft

Marcus D Nuncy

A modular digital robot control includes an electronic arm interface board provided with circuitry for performing robot arm dependent functions. Included are circuitry for generating power amplifier control signals in response to input voltage command signals and circuitry for processing and manipulating position, velocity and motor current feedback signals. An electronic torque processor board is provided with paired torque microprocessors for operating each of respective torque control loops for respective robot joint motors. The torque microprocessors generate the voltage commands in response to input torque commands and feedback motor current signals. An electronic servo control board is provided with paired position/velocity microprocessors for operating position and velocity control loops for the respective joint motors. The position/velocity microprocessors generate the torque commands in response to input position commands and feedback position and velocity signals. The servo control board further includes system resource facilities providing general support for the operation of the microprocessors and includes a DMC controller and two asynchronous controllers for communications interfacing with local input/output devices and other systems and devices. When executed in one of the position/velocity microprocessors, a stored motion program uses trajectory planning and interpolation to generate position commands in accordance with predefined moves set forth in a robot program. The servo control, torque processor and arm interface boards are interconnected to provide a complete basic control for the robot joint motors. An optional fourth electronic board can be connected to the basic control. It is called a system board and it includes paired system microprocessors that execute the motion program enabling the expanded control to provide extended robot control performance.

Modular robot control system

A digital robot control is provided with position/velocity and torque control loops with microprocessor servo controllers in each. The position/velocity servo controller includes two microprocessors that operate as a servo engine in providing position/velocity control for six robot axes. One microprocessor operates as a manager to perform data processing and coordination tasks supportive to position/velocity control. The other microprocessor performs position and velocity servo calculation tasks and operates as a slave processor to the position/velocity control manager. The programming for the position/velocity control sends manager position and other commands and position and velocity feedback from other control levels to the position/velocity calculator and sends torque commands received from the calculator to the next lower control level. The calculator employs position/velocity control algorithms in making torque command calculations.

Multiprocessor position/velocity servo control for multiaxis digital

A robot is provided with an arm having a plurality of motor driven joints. A power amplifier supplies drive current to each joint motor. Respective digital feedback control loop arrangements generate voltage commands from which signals are generated to operate the power amplifiers. Digital motor current, position and velocity feedback signals are generated for position, velocity and torque control loops in the digital feedback control loop arrangement. System resource facilities provide general support for the operation of the digital feedback control loops and include three separate communications controllers, a dual port microprocessor interfacing memory, a time stamp clock, a program memory and a nonvolatile data memory. A system level microprocessor based system or a microprocessor based position/velocity control system executes motion software from the program memory means according to whether the user desires an expanded performance robot control or a basic robot control. In the basic control, only the position/velocity microprocessor system is included and it is coupled to the system resource facilities. In the expanded control, both microprocessor systems are included and both are coupled to the system resource facilities.

Basic digital multi-axis robot control having modular performance

A completely digital robot control operates at a predetermined sampling rate. The robot arm has a plurality of joints with each driven by an electric brushless or brush-type DC motor which is in turn supplied with drive current by a power amplifier bridge circuit having power switches connected therein to supply motor winding current in the forward or reverse direction. Incremental or absolute encoders and tachometers provide for generating digital position and velocity feedback signals generated synchronously with the sampling rate. Digital motor current feedback signals are also generated synchronously with the sampling rate. Paired position/velocity microprocessors generate torque commands for each of the robot axes at the sampling rate in response to the position commands and the position and velocity feedback signals. Paired torque microprocessors generate motor voltage commands for each of the robot axes at the sampling rate in response to the torque commands and the current feedback signals. Pulse width modulators generate digital motor control signals for each of the robot axes at the sampling rate in response to the voltage commands. The digital control signals for each axis are coupled to control terminals of the corresponding power switches to control on/off switch time and satisfy the motor voltage commands and thereby satisfy the position commands.

Digital control for multiaxis robots

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Brookfield, CT, United States of America

Barrett L Booth