Abstract
A statically-balanced direct drive robot manipulator is being constructed at the University of Minnesota for analysis of manufacturing tasks such as deburrlng and grinding when Impedance Control (8, 10, 11) is used to control the robot. This mechanism using a four bar linkage is designed without extra counterweights. As a result of elimination of the gravity forces on the drive system, smaller actuators (and consequently smaller amplifiers) are chosen to guarantee the acceleration of about 5g without overheating the motors. This mechanism results in closed-form solution for Inverse kinematics. The closed-form solutions for dynamic and Inverse kinematic have been derived. High torque, low speed brush-less AC synchronous motors are used to power the robot. The relatively “large” workspace of this configuration is suitable for manufacturing tasks. Graphite epoxy composite material is being used for the construction of the robot links.
