Research On Robotic System For Eva Spacesuit Joint's Damping Paramenters Measuring

Spacesuit is the necessary protective equipment of manned spaceflight. It is the most important component of life security system of astronaut. With the development of manned spaceflight, astronaut will make astronauts'extravehicular walking possible in the near future in my country. EVA spacesuit provides not only life security system for astronaut but also excellent movability performance, especially the movability performance of upper limbs can ensure astronauts to complete EVA tasks smoothly. Currently, the EVA spacesuit's design and processing has almost been completed. A spacesuit measuring system is required to verify and evaluate our own spacesuits. This dissertation comes from the design and manufacture of measuring system for spacesuit joint's damping parameters, which is applied in National Manned Spaceflight Project. A novel method of measuring spacesuit joints'damping parameters has been put forward. A theoretical system based on this method has been developed. The test has been built. Experiments prove that the correctness and validity of the measuring principle have been done.The test of EVA spacesuit'joint damping parameters include EVA spacesuit arm and EVA spacesuit glove. The testing device of EVA spacesuit arm joint damping parameters is the same as IVA spacesuit joint torque testing device. Keeping the original mechanical devices and hardware unchanged, this project will mainly focus on solving the kinematics and dynamic algorithm problem of EVA spacesuit arm and meanwhile extending the software making it qualified both in testing EVA and IVA spacesuit arms. Based on the theory of robotics a novel measuring method for EVA spacesuit glove has been put forward. Based on the novel measuring method, a three fingers exoskeleton robot system has been developed.A new type of exoskeleton manipulator based on planar four-bar parallelogram mechanism was developed. This kind of manipulator joint could rotate about a fixed center that can avoid disturbance between exoskeleton fingers and glove. The relative motion of finger different joint is coupled through gear-linkages. This design can reduce DOF and complexity of finger system. It is difficult to calculate kinematics for mlti-linkages system. Rely on manipulator special motion character a kinematics model of the manipulator is given through built a virtual finger.The mechanical components, drive components, sensor components and control components are integrated in one exoskeleton finger. The slave controller (FPGA) not only realizes all sensors information acquisition, motor drive, but also realizes the high-speed point to point communication with master controller. The DSP/FPGA control card as master controller realizes control algorithm and trajectory planning. The distributing control strategies of robot satisfy real time control and the requirements of glove measuring.Based on disturbance observer (DOB) and robust feedback controller, a new two-loop control strategy is proposed. In the inner-loop, DOB is designed to compensate effect of disturbance. Depend on the dynamic of exoskeleton finger the proper linear plant mathematical model is built that load dynamics are represented by a feedback uncertainty model, and system uncertainties are analyzed. Based on structure singular value theory outer-loop feedback controller is designed, for system uncertainties which ensure system performance. Applied two-loop control strategy, the system can restrain big disturbance and has robust performance and robust stability for model uncertainties.The models of EVA spacesuit arm and glove have been built and kinematics algorithm has been developed. Based on EVA spacesuit arm special flexible joint structure, a new and high efficiency inverse kinematics algorithm, nearest neighbor algorithm is presented. It can obtain approximate spacesuit joint angle on anyone measuring position. Presented spatial sphere two steps searching method solve the defects of large memory and low searching efficiency. The emulator results from the SGI work station verify that the new algorithm can meet the testing system's need very well in calculation precision and real-time capability.Measuring experiments of spacesuit joint damping parameters have been done on the actual platform. For improving EVA spacesuit arm joint measure precision, the compensation of chuck weight and joint gravity is used. Experimental results proved that the theoretical system is correct and available, and the measuring system have high preciseness.