A new revolute robot manipulator adapting the closed-chain mechanism

Abstract

Conventional robot manipulators actuated by motors with conventional speed reducers such as the harmonic drive or RV have weakness in the load capacity since the speed reducers are not stiff enough. To overcome this, we propose a four-bar-link actuator driven by the ball screw, which has a high stiffness and high torque transmission ability, and propose a new type of four degree-of-freedom revolute robot manipulator adapting the proposed actuators. The base joint of the robot is actuated by the motor with the conventional speed reducer, and the other joints are actuated by the proposed actuators. The kinematics and dynamics of the robot are analyzed in the joint coordinate and in the Cartesian coordinate. For the performance tests of the robot, a four degree-of-freedom revolute robot was built. Through the performance tests, the results of superior load capacity and positioning accuracy are presented. © 2005 Wiley Periodicals, Inc.