No abstract

A computationally efficient kinematic control scheme is presented for a seven-degree-of-freedom redundant robot with spherical wrist. scheme uses a gradient projection optimization method, which eliminates the need to determine the generalized inverse of the Jacobian when solving for joint velocities for given Cartesian end-effector velocities. Closed-form solutions are obtained for joint velocities using this approach. The application of this scheme to the seven-degree-of-freedom manipulator at the Center for Engineering Systems Advanced Research (CESAR) is described. This

The purpose of this paper is to develop a controller for a force-reflecting teleoperator system having kinematically dissimilar master and slave. The controller is a stiffness controller for both the master and the slave. A mathematical problem associated with representing orientations using Euler angles is described, and Euler parameters are proposed as a solution. The basic properties of Euler parameters are presented, specifically those pertaining to stiffness control. The stiffness controller for both the master and the slave is formulated using Euler parameters to represent orientation and a Liapunov stability proof is presented for the controller. The master portion of the control scheme is implemented on a six-degree-of-freedom master.

The movement of redundant manipulator joints that does not cause any end‐effector motion is referred to as its self motion. Control schemes for redundant manipulators utilize its self motion to optimize a performance criterion. Thus, commanded joint motion at each sampling step is the sum of the minimum joint motion required for the desired end‐effector motion and the self motion. However, the amount of self motion is limited by the bounds on actuator velocities, which are limited by the actuator torque bounds. A scheme is presented to determine the magnitude of self motion, the direction of which is determined by a gradient projection scheme. Implementation of this scheme on a Motorola 68020 VMEbus‐based controller of a seven‐degree‐of‐freedom manipulator is described.

The remediation of single-shell radioactive waste storage tanks is one of the urgent tasks of the Depamnent of Energy that challenge state-of-the-art equipment and methods. The use of long-reach manipulators is being seriously considered for this remediation task Because of high payload capacity and high length-to-cross-section ratio requirements, these long-reach manipulator systems * Research sponsored by the Office of Technology Development, U.S. Department of Energy, under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Xnc. schemes. The development of a TWRMS may be one of DOEs most significant robotics projects.