Research On A Large Space Manipulator Joint And Its Vibration Suppression Control

Tracking human pace into space, space manipulators, as symbols of advancedtechnology in astronautics, have made a significant progress. Large space manipulatorsystems (LSMS), serving large-scale orbital devices such as space stations, arebecoming a focus in research on space manipulators. Combining research-in-advance onLSMS by the National Key Lab, key techniques in R&D of the LSMS joint are studiedin this thesis. Ground-testing prototypes of LSMS joints are developed. Research onmeans of vibration suppression control of the joint is carried out.A new, high-integrated, modularized joint for LSMS is developed, integratingmechanism, sensors, drive, control, power and communication. Considering the jointtorque to be affectless in zero-g conditions in space, modularization is adopted, fordecreasing the R&D cycle and expense of the LSMS, as well as making convenience ofits maintenance. A large hole through the center is applied to protect the cables fromeffects of hard conditions in space. Several sorts of auxiliary assemblies are developed,such as a limitation device to limit the joint’s moving range and expand the positionsensor’s measuring range, a manual-drive device in case of an emergency shut-down,and an orbital replacement connector for orbital maintenance of the joint.Plenty of sensors are integrated in the joint to improve its intelligence. A sensorsystem is built for providing reliable communication between joint motion and thecontroller. Therein, each of the position sensors, torque sensors, and current sensors isutilized to gather signals for feedback/feedforward needed by the joint control system.In addition, thermal sensors are in use to fulfill the joint function of thermal control, toensure working conditions of the system.Theories of vibration suppression control of LSMS joint are mainly studied in thisthesis. The dynamic&mathematic models of the flexible joint are established, andsimulation analysis is implemented. Furthermore, a triple close-loop PD control strategybased on joint trajectory planning is put forward, and is validated to be resultful tosuppress vibration of joint motion through experimental research.