Research On Structure Design And Control Of A Snake Like Robot For Planetary Surface Exploration

Planet’s surface exploration is a great and arduous task and foundation can be laid for development of planetary resources by studying planet geological characteristics and space environment and exploring the formation and evolution history of the planetary system. The planet’s geological surface with more bumpy roads is complex and difficult for traditional robot to adapt to the environment with disadvantages of large size, less movement dofs(degrees of freedoms). A snake-like robot is extremely suitable for application in rugged roads or narrow space with advantage of redundant structure, movement flexibility and low gravity center. This paper is written for demand of planet’s surface exploration. Two different snake-like robot configurations are designed and then kinematics analysis and gait planning are done. At last, prototype of snake-like robot is developed and experimental study is carried out in the end.According to application requirements of snake-like robot, function and performance index are determined. Two kinds of snake-like robot configurations and corresponding modular joints, namely modular single dof joint and modular double dof spherical joints, are designed based on requirement of function and indicators. In practice, corresponding configuration and joints with advantage of directly output of joint torque and simplicity of control of the former joint and high actuator drive capacity of the latter are used according to specific situation. To accomplish gait planning and motion control of snake-like robot, kinematics models are established using D-H method based on two configurations. According to analyze biological snake movement forms, creeping gait, rolling gait, serpenoid curve gait are planned based on designed configurations. Simulation is done by writing gait planning software program and accuracy of algorithm and theoretical derivation are verified in the process of simulation. Control system is core of snake-like robot motion control. Based on modular design thought, embedded hardware controller is developed based on the core ARM processor. The real-time operating system uc/OS-ii is transplanted and management of multitasks is done by writing task control function using flexible task scheduling mechanism of uc/OS-ii.Based on above work, mechanical processing, assembly and debugging of two configurations snake-like robot prototype are completed and motion control experiments under different road conditions are carried out with one prototype, including creeping, rolling and serpenoid curve gait and obstacle avoidance experiments on indoor ground, grass, sand and other outdoor environment. Results show that motion ability of snake-like robot is so strong that it meets application requirements on variety road conditions.