Accuracy Synthesis of a 3-RPS Parallel Robot Based on Manufacturing Costs

Pose accuracy is an important issue for parallel robot being used as mirror supporting system of telescope. One challenging topic is the accuracy synthesis which deals with the optimal design of the manufacturing and assembling tolerances of each component under the given pose accuracy. First, the error model of the 3-RPS parallel robot is built based on total derivation of the kinematic equations. And the error variable of each spherical or rotate joint can be expressed as a single boundary error parameter but not three independent position parameters. Then, the accuracy synthesis model is formulated taking the manufacturing costs as the optimization objective and the accuracy requirements as the constraint condition. Finally, the genetic algorithm is used to solve the optimization problem and a simulation example is given. The results show that the accuracy synthesis method based on manufacturing costs can satisfy the need of pose accuracy and is better for engineering application than the method based on error sensitivity.