Abstract: In a device having a first member and a second member which are driven relative to one another by an actuator, a servocontrol derives feedback by sensing the torque applied on one of the members by the actuator. The actuator drive signal is modified by a compensation network in response to the torque measurement to provide stability across a bandwidth extending beyond the resonant frequency of the members, thereby providing smooth, accurate and precise motion.

Abstract: A digitally controlled industrial robot comprises a set of unitized and integrated joint drive modules which can be assembled in series to form an arm. The joints are of two basic types, pitch joints and roll joints, with the roll joints providing rotation about the longitudinal axis of the manipulator and the pitch joints providing rotation about axes which are substantially perpendicular to and offset from the roll joint axes. Any number of joints may be assembled to comprise the manipulator, permitting the configuration of a kinematically redundant manipulator. A servocontrol derives feedback from sensing the motive force on a driven member and compensates the drive signal accordingly. More particularly, the torque exerted on each roll and pitch joint is measured and used for feedback to provide stability and optimum bandwidth for the servomechanism.

Abstract: A digitally controlled industrial robot comprises a set of unitized and integrated joint drive modules which can be assembled in series to form an arm. The joints are of two basic types, pitch joints and roll joints, with the roll joints providing rotation about the longitudinal axis of the manipulator and the pitch joints providing rotation about axes which are substantially perpendicular to and offset from the roll joint axes. Any number of joints may be assembled to comprise the manipulator, permitting the configuration of a kinematically redundant manipulator. A servocontrol derives feedback from sensing the motive force on a driven member and compensates the drive signal accordingly. More particularly, the torque exerted on each roll and pitch joint is measured and used for feedback to provide stability and optimum bandwidth for the servomechanism.

Abstract: A seismic testing apparatus is provided in which linear motion or excitation of a horizontally disposed table is achieved simultaneously along three mutually orthogonal axes by means of independently operable hydraulic-actuator assemblies. Rotational or torsional motion of the table about the linear excitation axes is resisted by separate, mechanical rotation-inhibiting means each consisting of a torsionally rigid structure disposed parallel to the table and perpendicularly to their respective associated axes of excitation. The torsionally rigid structures are each connected to the table at two spaced-apart points, with all four points of connection lying in the same plane.