Kinematics Analysis of a Hybrid Robot Consisting of a SCARA and a Parallel Wrist For some manipulation tasks needing to change objectsxe2x80x99 orientation and position quickly, a hybrid robot, consisting of a 4DOFs SCARA and a 3DOFs (2R1T) parallel wrist, is presented. First, the swing and translation characteristics of the parallel wrist are quantitatively analyzed by numerical method, and its maximum swing angle and optimum working curve are obtained. A swingrotation method for representing the attitude of the parallel wrist is proposed, and it can be transformed with the commonly used AzimuthSwing method, which is the key to decouple kinematics of hybrid robots. Then, the singularity of the mechanism, when its attitude expressed by the proposed method, is also analyzed. The forward and inverse kinematic equations are derived in an analytical form. Finally, the kinematics simulation based on ADAMS verifies the correctness of the robot kinematics.

Decoupling Control and Simulation of a 3RSR Spheroid Parallel Wrist The control of position and trajectory tracking are critical issues in parallel robots. Traditional PID tracking algorithms, which are based on kinematics control use the position and speed deviation as a negative feedback in order to design a controller. However, this method is not only hard to maintain the excellent dynamic and static quality of a system, but it is also incapable of realizing complete decoupling, and it needs large energy to be controlled. To overcome such drawbacks, this paper proposes, a computed torque decoupling control strategy for a 3RSR spheroid parallel mechanism. The control strategy includes a computed torque decoupling control method with traditional PD controller and selfadaption fuzzy controller. It was proved that the corresponding Lyapunov function is global asymptotic stable in the ideal and nonideal estimation. A set of ADAMSMATLAB dynamic simulations were established based on virtual prototyping technology. The results demonstrated that the performance of the control scheme with selfadaption fuzzy controller is more effective than that with PD controller.