Papers by Author: Ji Zhao

Abstract: Making large automatic device for polishing freeform surface of large mold has many disadvantages. We propose a new thinking of polishing large freeform surface with small mobile robot, and develop a novel small mobile polishing robot which has good maneuverability for moving on and polishing curved surface continuously. By analyzing its kinematics model, algorithm for tracking polishing path is designed, in which discrete points along planed polishing path on surface are taken as robot’s navigation points. And virtual robot view methods are designed in the tracking algorithm to avoid the oscillate phenomena. Both the simulation and field experiments prove that this type robot can satisfy the requirement of polishing process.

Abstract: The hybrid polishing kinematics machine tool (HPKMT) which is made up of “3 axes parallel + 2 axes series” is developed with the specially designed elastic polishing tool system for the polishing operation on the free-form surfaces by using the characteristic of the elastic polishing adequately by the authors. In order to control the HPKMT effectively, its characteristic of the kinematics and dynamics need be known deeply. Moreover, the problem of inverse dynamics is the theory foundation to apply dynamic control of the HPKMT. The analysis of the inverse of mechanism is the important part in the research of dynamics. On the basis of the differential equations of flexible multi-body dynamics, this paper discusses on the condition of knowing the trace, posture and velocity for the end of bodies how to solve the constraint force and constraint moment of each joint on the 3- PTT parallel mechanism and two-joint series mechanism.