Accuracy analysis and optimal design of palletizing robot with joint clearance

This paper presents a systematic study of the optimal design problem for a palletizing robot with joint clearance based on the robot accuracy analysis theory which is combined with mechanism analysis method reasonably. The mechanical structure of palletizing robot is divided into three special four-link (parallelogram) mechanisms. And the pose (position and orientation) error of every parallelogram has been analyzed with parallel manipulators accuracy analysis method. By the error transformation relationship of the three parallelograms with joint clearance, an efficient formulation is proposed to evaluate the maximal pose error of palletizing robot. Base on the maximal pose error formulation, an optimal design method of the palletizing robot is obtained by minimize the normalization error we have proposed. Finally, a numerical example shows that the optimal design with joint clearance presents improved performance on accuracy.