A Gait Design And Motion Control Of Quadruped Robot Baesd On Rapid Control Prototype

Quadruped robots are highly adaptable to different terrains and have been widely used in transportation,engineering exploration,special operations,and military applications.Although significant progress has been made in the research on locomotion control of quadruped robots,issues such as unstable motion still exist in practical controls.Moreover,traditional development processes require designing hardware controllers and writing driving code for independent validation of robot algorithms,which is time-consuming and labor-intensive.To enhance the obstacle-crossing and smooth motion abilities of quadruped robots,as well as to shorten development cycles and better validate control algorithms,this study focuses on a hydraulic-driven quadruped robot and conducts gait planning and Stability design and control verification using Rapid Control Prototyping(RCP).The main research work includes:1.Researching the three-dimensional structure of the quadruped robot,analyzing its body structure and leg configuration based on the characteristics of hydraulic-driven quadruped robots and their motion features.The kinematic model is formed through the resolution of both forward and inverse kinematics equations,and the foot-end reachable space of a single leg is obtained using Monte Carlo simulation.The posture control is also analyzed to provide a foundation for gait planning.2.Designing the motion control logic,including the control logic layer,state execution layer,and position feedback layer.Adopting a control method of "feedforward+feedback",the control logic layer and state execution layer are used for decision-making and trajectory planning of forward control,while the position feedback layer monitors states and stability through sensor feedback data.3.Designing a statically stable stepping gait with good stability and obstacle-crossing capability based on the motion control logic.Specific steps include gait cycle design and motion trajectory planning.The Zero Moment Point(ZMP)method is used to calculate dynamic balance stability margin as an evaluation criterion for robot motion stability,and the trajectory of center of gravity adjustment is planned based on this criterion.The foot-end trajectory with obstacle-crossing capability is also designed,and a fifth-order polynomial interpolation method is used to optimize the output joint angles to effectively solve the problem of foot impact force caused by joint acceleration mutation.4.Designing the motion control system of the quadruped robot and conducting simulations.The main modules of the system include the static gait state machine,trajectory planning,forward and inverse kinematics,zero-impact optimization of foot-ends,Model Predictive Control(MPC)-based trajectory tracking controller,and robot model.The 3D graphics of the robot are drawn using Solid Works and imported into Matlab/Simulink.The modules of the control system are established using Simulink toolboxes to complete the construction of the simulation environment.Static walking simulations are conducted by inputting predefined motion signals,and changes in Euler angles,center of mass displacement,and joint angles are collected and analyzed to verify the reliability of the robot structure,kinematic equations,and statically stable gait design.5.Establishing a prototype experimental platform consisting of a personal computer,RCP target machine,and robot system.Rapid Control Prototyping(RCP)is used for motion control of the robot,and the Ether CAT communication module of Simulink Real-Time is combined with real-time control to establish a communication connection between the personal computer and robot system.A drive state machine is used to make decisions for the overall control process of the robot system,and a Simulink user interface is created to realize real-time control,online tuning,and state monitoring of the robot.By integrating the hardware and software of the robot system and deploying the designed gait algorithm to the experimental prototype,the rationality of the gait planning and the accuracy of the motion control are verified through the results of the prototype motion experiments and the collected joint angle data.