Research On Self-growing Soft Robot For Space Station Fault Detection

As space station operates in harsh space environment such as high vacuum,strong radiation,and extreme temperature,it is necessary to detect and repair any failure of it in time,so as to ensure the safety of itself and astronauts in it.Limited by the internal structure size of space station and the easy-to-damage feature of precise instrument and equipment,this detection task can hardly be finished by traditional rigid robot.In contrast,self-growing soft robot moves via tip extension,with flexibility available for non-destructive detection and multidegree of freedom highly adaptable to various complicated narrow and small spaces.Thereby,applying self-growing soft robot to detecting internal failure of space station is of vital meaning to improve the operation and maintenance level of China’s space station.In this paper,functional designs of robot such as active steering in space,the carrying of front-end device and the controllability of growing movement are provided as per the failure detection demand of space station.Aiming at realizing remote operation of portable self-growing soft robot by systematic design and showing the space movement and tip detection capabilities of the robot,the research was mainly made as follows:Pneumatic evaginable extension of a thin flexible film was adopted to simulate the tip growing of vine.Provided that the size requirement of the main body was met,the spatial steering of the main body was realized by using a micro motor with coupled drives to contract the flexible wire.Stepping motor was used to control the growing of main body under the joint action of air pressure.Further,a tether-less front-end loading movement platform was designed to bear multiple payloads and equipment and keep them attached on the tip in the growing,contracting and steering processes of the main body.Finally,software and hardware designs of the self-growing soft robot were completed as per the functional demand.In addition,the joint model was simplified by virtue of the spatial steering movement formed by folding of the main body and a kinematic model analysis was completed.The result shows that axial growing of the main body can enlarge the working space and makes it available to steer for a large angle within a narrow and small space.Adopting the design size stated in the built-in scheme of steering module as simulated and verified by ABAQUS,the main body can stably steer at the front end and flexibly steer in a space.Based on the integrated prototyping system design of self-growing soft robot,a set of rational preparation procedures was formulated and relevant experimental research was finished.By testing the steering unit,it is verified that the simulation result is correct and the kinetic model analysis is applicable.Result of the main body prototype experiment reveals that self-growing soft robot can pass through small gaps non-destructively.By simulating a space station model,it is demonstrated that the main body can carry detection device to realize movement in complicated path and acquire image information.This verifies the effectiveness of the entire system.