Gait Planning And Control For A Quadruped Robot With Spine Driven By Parallel Mechanism

Due to the inherent characteristics of strong adaptability to environment and discrete supporting point,legged robots have stronger mobility than wheeled and tracked robots.The spine,as the central e leme nt of a ma mma l's body,can be used to increase the range of mot ion and absorb ground impact.Based on the quadruped robot with rigid body frame in the laboratory,a 3-RPS(R: Rotational joints,P: Prismatic joints,S: Spherical joints)parallel structure is added as the spine of a quadruped robot and its motion control is performed.Based on central pattern generator(CPG),twist ing forward ga it of spine quadruped robot is planned.First ly,the parallel spine is designed according to the bionics principle and the hound's spine configuration.After establishing the parallel spine space degrees of freedom and coordinate,the inverse kinematics model is established.Referring to the physical dimension,the relationship between the spine angle and each drive rod length is built to lay the foundation for the gait experiment of the subsequent spinal column.Secondly,ana lys is of longit ud ina l stable operating cond it ions of quadruped robot using Zero Moment Po int.Four Hopf Oscillator models which are coupled to each other are used to establis h the limb ic CPG network.The CPG parameters are obtained fro m the lo ngit ud inal stability cond it ions and the outp ut of the CPG is mapped to each joint.The motio n ge nerator is built to simulate the dyna mics of quadruped robot to realize the cont inuous walk ing of the robot under the conditio n of reasonable choice of parameters.However,when the robot walks in trot ga it,it will produce unnecessary displacement in yaw direction.Then,the dynamics of quadruped robot in diagonal gait is analyzed,and the reason of walking yawing in rigid body robot is illustrated.The simulation is used to verify that the passive flexion spine improve quadruped robot the yaw situation.The kinematics model of spine quadruped robot is established.The relationship between the spine layer and the limbs is obtained through biological observation and kinematics analysis.The optimum value of the CPG parameters of the spine is obtained by using the vector longitudinal stability margin analysis.The simulation validates that the active spine improves the stability,coordination of quadruped robot walking process,and reduces the yaw displacement of the quadruped robot walking.Fina lly,Parallel sp ine mot ion contro l syste m is set up and applies to the experime nta l plat for m of q uadruped robot.The control a lgor it hm was used to ensure that the moving plat form meets perspective plan.A trot gait experiment of quadruped robot with the active spine was performed to validate that the effectiveness in coordinating and stabilizing,and it can a lso reduce the yaw displacement.