Kinematics, workspace, design and accuracy analysis of RPRPR medical parallel robot

Abstract

In recent years, parallel robots find many applications in human-systems interaction, medical robots, rehabilitation, exoskeletons, to name a few. These applications are characterized by many imperatives, with robust precision and dynamic workspace computation as the two ultimate ones. Practical methods of kinematic's calibration make use of the linear differential error of the kinematics' model. This model is based on the Jacobian of the direct kinematics' model with respect to parameters of this model. The definition of the robot accuracy is usually related to robot positioning, so that the accuracy is defined as a measure of robot ability to attain a required position with respect to a fixed absolute reference coordinate frame. Such a definition is easily extended to trajectory tracking. Then, accuracy can be defined as a measure of robot ability to track the prescribed trajectory with respect to the absolute coordinate frame.