Statistically balanced direct drive manipulator

A practical architecture, using a four-bar-linkage, is considered for the University of Minnesota direct drive robot. This statically-balanced direct drive robot has been constructed for stability analysis of the robot in constrained maneuvers. As a result of the elimination of the gravity forces (without any counter weights), smaller actuators and consequently smaller amplifiers were chosen. The motors yield acceleration of 5 g at the robot end point without overheating. High torque, low speed, brush-less AC synchronous motors are used to power the robot. Graphite-epoxy composite material is used for the construction of the robot links. A 4-node parallel processor has been used to control the robot. The dynamic tracking accuracy-with the feedforward torque method as a control law- has been derived experimentally.