In view of the complex ground environment after disasters or wars, a robot with a variable structure is developed, which can be thrown or fired into the working area. The robot adopting spherical structure can be thrown or fired across some obstacles which are difficult for most existing robots to cross. After going into the working area, the robot can adopt the four-wheel structure with two passive degrees of freedom to realize the moving work. In order to control movement of the robot effectively, a kinematic model is established, in which the geometric constraint and the non lateral slip constraint of the front and rear bodies are considered for the unfolded structure, and the cause of the robot's trajectory error along a curved path is analyzed. The simulation for the robot to follow a sinusoidal trajectory is performed, and the trajectory error and its influencing factors are studied. An experiment is performed to verify the presented model and the simulation results, and good mobility of the robot is demonstrated.
[1] Li Y, Huang Q, Huang Y C, et al. A throwable miniature robotic system[C]//IEEE International Conference on Automation and Logistics. Piscataway, USA: IEEE, 2011: 114-118.[2] Szynkarczyk P, Czupryniak R, Trojnacki M. Current state and development tendency in mobile robots for special applications [C]//6th Workshop on European Scientific and Industrial Collaboration on Promoting Advanced Technologies in Manufacturing. 2008: 30-41.[3] Tadakuma K, Tadakuma R, Nagatani K, et al. Throwable tetrahedral robot with transformation capability[C]//IEEE/RSJ International Conference on Intelligent Robots and Systems. Piscataway, USA: IEEE, 2009: 2801-2808.[4] Qu Y, Liu R, Chen R, et al. Development of a reconfigurable miniature throwable robot for indoor surveillance[C]//7th IEEE Conference Industrial Electronics and Applications. Piscataway, USA: IEEE, 2012: 502-506.[5] Kamimura A, Kurokawa H. High-step climbing by a crawler robot DIR-2 -- Realization of automatic climbing motion[C]// IEEE/RSJ International Conference on Intelligent Robots and Systems. Piscataway, USA: IEEE, 2009: 618-624.[6] Ye C L, Lv G M, Ma S G, et al. Development of a variable parallelogram tracked mobile robot[C]//IEEE International Conference on Robotics and Biomimetics. Piscataway, USA: IEEE, 2012: 2156-2160.[7] Kamegawa T, Yamasaki T, Igarashi H, et al. Development of the snake-like rescue robot "KOHGA"[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA: IEEE, 2004: 5081-5086.[8] Osuka K, Kitajima H. Development of mobile inspection robot for rescue activities: MOIRA[C]//IEEE/RSJ International Conference on Intelligent Robots and Systems. Piscataway, USA: IEEE, 2003: 3373-3377.[9] Ye C L, Ma S G, Li B, et al. Design and locomotion analysis of an unit for reconfigurable robots[C]//World Congress on Intelligent Control and Automation. Piscataway, USA: IEEE, 2008: 3886-3891.[10] Ye C L, Ma S G, Li B, et al. Turning and side motion of snake-like robot[C]//IEEE International Conference on Robotics And Automation. Piscataway, USA: IEEE, 2004: 5075-5080.[11] 张大伟, 李振波, 陈佳品.基于被动万向连接的可重构微型移动机器人设计与控制[J].机器人, 2011, 33(6):719-725. ewline Zhang D W, Li Z B, Chen J P. Design and control of reconfigurable mobile microrobot with passive universal connector[J]. Robot, 2011, 33(6): 719-725.