Reduction of friction and inertia effects in digitally controlled force-reflecting servomanipulators.

The Advanced Servomanipulator (ASM) developed at the Oak Ridge National Laboratory (ORNL) during the period from 1982 to 1986 Improved the reliability and maintainability of remotely operated manipulator systems. Due to the unique geared torque transmission techniques Implemented on the system, many demands were placed on the control system to provide satisfactory force-reflecting operation to a human operator. The fundamental problem addressed In this dissertation Is the reduction of operator perceived friction and Inertia forces within a manipulator system that reflects environmental forces to the human operator.

A survey of previously Implemented control techniques begins the effort. Modelling of the dual force-reflecting servomechanism and the development of performance parameters quantifying operator perception of the system were accomplished. A series of compensation algorithms were developed and Implemented, both In the simulation and on a single axis force-reflecting test fixture. The resulting compensation, which dynamically reduces the force-reflection based on the speed of motion, noteably Improved the system performance in both simulation and application. This compensation has been Implemented on a complete manipulator control system and results in less operator effort required to perform manipulation motions, allowing more rugged construction techniques to be used in the design and Implementation of future force-reflecting manipulators.