For the shortcomings and the insufficiencies in study of stride size of radially symmetrical hexapod robots, a workspace intersection method for parallel mechanism is proposed. In the method, the parallel mechanism composed of robot body, supporting legs and ground is divided into different branches, and according to the intersections of the workspaces of all the branches, and the stride size and stability margin of the robot can be deduced at any body height. By using this method, the maximum feasible stride size and stability margin can be obtained when the body height and the footholds are known. And its extreme stride size and the corresponding footholds at a certain body height can be solved. Meanwhile, the maximum stability margin and the corresponding suitable footholds can be determined while the stride size and body height are certain. This method provides a good reference for the radially symmetrical hexapod robot to choose suitable footholds, body height and stride size while walking in different gaits.
[1] Hirose S. Three basic types of locomotion in mobile robots
[C]//5th International Conference on Advanced Robotics. Piscataway, NJ, USA: IEEE, 1991: 12-17.
[2] Lee T T, Liao C M, Chen T K. On the stability properties of hexapod tripod gait
[J]. IEEE Journal of Robotics and Automation, 1988, 4(4): 427-434.
[3] 苏军.多足步行机器人步态规划及控制的研究
[D].武汉:华中科技大学,2004. Su J. The research of the gait planning and control of the multilegged walking robot
[D]. Wuhan: Huazhong University of Science & Technology, 2004.
[4] Yang J M, Kim J H. Fault-tolerant locomotion of the hexapod robot
[J]. IEEE Transactions on Systems, Man, and Cybernetics, Part B, 1998, 28(1): 109-116.
[5] Yang J M, Kim J H. A strategy of optimal fault tolerant gait for the hexapod robot in crab walking
[C]//IEEE International Conference on Robotics and Automation. Piscataway, NJ, USA: IEEE, 1998: 1695-1700.
[6] Preumont A, Alexandre P, Ghuys D. Gait analysis and implementation of a six leg walking machine
[C]//5th International Conference on Advanced Robotics. Piscataway, NJ, USA: IEEE, 1991: 941-945.
[7] Chu S K K, Pang G K H. Comparison between different model of hexapod robot in fault-tolerant gait
[J]. IEEE Transactions on Systems, Man, and Cybernetics, Part A, 2002, 32(6): 752-756.
[8] Wang Z Y, Ding X L, Rovetta A. Analysis of typical locomotion of a symmetric hexapod robot
[J]. Robotica, 2009, 28(6): 893-907.
[9] 丁希仑,王志英,Rovotta A.六边形对称分布六腿机器人的典型步态及其运动性能分析
[J].机器人,2010,32(6): 759-765. Ding X L, Wang Z Y, Rovotta A. Typical gaits and motion analysis of a hexagonal symmetrical hexapod robot
[J]. Robot, 2010, 32(6): 759-765.
[10] Kamikawa K, Arai T, Inoue K, et al. Omni-directional gait of multi-legged rescue robot
[C]//IEEE International Conference on Robotics & Automation. Piscataway, NJ, USA: IEEE, 2004: 2171-2176.
[11] Roy S S, Singh A K, Pratihar D K, et al. Analysis of six-legged walking robots
[C]//National Conference on Machines and Mechanisms. 2009: 259-265.
[12] 韩宝玲,王秋丽,韩庆生.六足仿生步行机器人足端工作空间和灵活度研究
[J].机械设计与研究,2006,22(4): 10-12. Han B L, Wang Q L, Han Q S. Mechanical optimization and analyses of hexapod walking bio-robot
[J]. Machine Design and Research, 2006, 22(4): 10-12.
[13] 陈学东,孙翊,贾文川.多足步行机器人运动规划与控制
[M].武汉:华中科技大学出版社,2006. Chen X D, Sun X, Jia W C. Motion planning and control of multilegged walking robot
[M]. Wuhan: Huazhong University of Science & Technology Press, 2006.
[14] Song S M, Choi B S. The optimally stable ranges of 2n-legged wave gaits
[J]. IEEE Transactions on Systems, Man, and Cybernetics, 1990, 20(4): 888-902.
[15] Chen X D. Novel formulation of static stability for a walking quadruped robot
[J]. Chinese Journal of Mechanical Engineering: English Edition, 2003, 16(2): 120-122.
