Kinematic Analysis and Optimal Design of a Wall-mounted Four-limb Parallel Schönflies-motion Robot for Pick-and-place Operations

In this paper, a parallel Schönflies-motion robot, with four identical limbs and one single-platform end-effector, is introduced for pick-and-place operations. Compared to the conventional four-limb robot counterparts, this robot can be mounted to a base or hanged on the wall, of which the installation is exempt from the multi-beam mounting frame. The input and output transmission indices corresponding to two pressure angles are defined to evaluate the motion/force transmission quality of the robot and to identify singularity. Kinematic optimal design is conducted to optimize the robot’s geometric parameters, wherein the transmission indices are taken as the performance evaluation criterion. A set of optimal geometric parameters for the robot is identified, which admits a large cuboid translational workspace free-of-singularity with rotational capability ±45^∘, suitable for pick-and-place applications.