The Research On Space Manipulator Servo Control System Based On CANopen

Space manipulator is an intelligent robot, with precise operating capability and visual recognition ability, it's a highly integrated mechatronic control systems, has independent analysis capabilities and can be remotely controlled by astronauts. In this thesis, we studied the "6 degree-of-freedom space manipulator project", a research project by special Robotics Lab of Hunan University and Space Research Institute, proposed the research of manipulator control system based on CANopen, the research objective is achieving the point-to-point movement of manipulator. The main point of the research includes manipulator distributed control system design, motor control design based on CANopen protocol, and kinematics analysis of 6 degree-of-freedom manipulator.The present situation of space manipulator development was introduced in this thesis, pointed out that the space manipulator has a wide range of applications in the field of space technology, such as space exploration and space rail service. In accordance with the requirements of the research, this paper analyzed some key technologies about the manipulator control system based on CANopen, distributed control system technology and fieldbus application technology.The overall design scheme of manipulator distributed control system was proposed in this thesis, by studying the general structure of space manipulator system. The thesis pored over the hardware design of manipulator distributed systems, central controller, bus communication, articulation mechanism and distributor, making sure that the module performance to the system control requirements. The overall design of the manipulator robotics servo control system provided the hardware conditions for the research.CANopen protocol configuration was the communication infrastructure for the motor motion control under CAN bus. This thesis introduced the features and the development of CAN bus, pored over the communication model and core concepts of CANopen protocol. In accordance with CANopen communication sub-profile and motion control sub-protocol, combined with the motion control requirements of this research, the thesis designed the heartbeat configuration, PDO mapping configuration, and motion control configuration for the manipulator control system.Manipulator kinematics analysis is the theoretical basis of the point-to-point movement. In this thesis, the modified Denavit-Hartenberg method was used to conduct the manipulator model and space coordinate system, according to the structural characteristics and joint constraint relations. The thesis discoursed the mapping process of manipulator extremity position description from Cartesian space to joint space, and completed the algorithm of inverse kinematic.Finally, the manipulator control system software architecture and motor control program design was pored over in the thesis. The motor control program design encapsulated class ArmCoM and class MotorControl, class ArmCoM implemented the communication between controller and CAN bus, class MotorControl encapsulated interface functions for motion control based on CANopen protocol. The point-to-point movement through the manipulator servo control experiment was implemented in this thesis.