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Based on pneumatic artificial muscle actuator (PMA) technology, a power assist device for the elbow joint actuated by a pair of antagonist muscles was designed. Dynamic models of the power assist device were established, driving characteristics of the device were simulated. The results show that the PMA complies with the requirements of the device, and the device can compensate the resistance caused by the spacesuit and the inertia forces by motion. Hence the device will be a great help for astronauts EVA operation. The research is used as a foundation for future development of power assist spacesuit.

Because of the microgravity environment of the space and mobility restriction by pressurized spacesuit, astronaut extravehicular operation is quite different from that in the ground. For ensuring high reliability of extravehicular operations, the astronauts need to do a great deal of training in simulated environments. A 3-dof of micro-gravity operation training system is designed in the paper, and the kinematics and dynamics of the interaction between the space station system and spacesuit system were simulated. Pressure and flow velocity distributions in the air orifice and air cavity were calculated by FLUENT. Experiments on the bearing capacity characteristic were carried out. The carrying capacities of the air bearing in different air pressures were achieved. Experiments validated the simulation analysis. The research provides the basis for the development of multi-degree of freedom space microgravity ground simulation technology, provides a basis for further development and application of flotation technology as well.

Abstract. This paper takes a specific routing protocol as an example and formally analyzes the protocol in a machine-assisted theorem proving tool Isabelle/HOL, to prove that routing protocols in wireless networks can be attacked by designing particular attacking schemes and can also be protected from attacks by modifying protocol contents. The paper first gives the specification of the routing protocol and formal definition of the attacker, and then finds the security vulnerability in the routing protocol through strict logical analysis.