Research On Structural Characteristics And Control System Of Mechanical Leg Of A Quadruped Robot

Benefiting from the process of computer technology,network technology,sensor technology and other related science and technology,the development of robot technology are changing with each passing day and has become the leading edge of the development of science and technology today.Legged robot has vast application prospects because of its discrete ground support and strong adaptability for special terrain such as obstacles,ditches and other complex and unpredictable environment.Legged robot is divided into biped robot,quadruped robot,hexapod robot and so on,among them,the quadruped robot becomes the research hotspot as its simple and flexible structure,strong carrying capacity and good stability.Quadruped robot research focuses on the structure design,control method,control system and gait planning and so on,mainly to solve the questions of quadruped robot on loading capacity,endurance,motion control,environmental awareness and autonomous obstacle avoidance,and other functions.Starting from the features and requirements of quadruped robot,the mechanical leg structure was designed in this paper regarding biological dogs as the research object,which meets the bionic requirement,the principle of low inertia and flexibility,and then the kinematics characteristics were analyzed in order to complete the motion planning.BLDCM was chosen as joint driver of the mechanical leg of quadruped robot,and both of the two driving motors were installed in the fuselage of the hip joint.According to the characteristics of the driving motor and control requirements of the mechanical leg,the control system design of the mechanical leg was completed in this paper,including the dual closed-loop PID control algorithm of BLDCM,design of hardware circuit and software program.Finally,the effectiveness of the control system of mechanical leg and the rationality of the motion planning were verified by experiment.The content of this paper is divided into the following several aspects concretely:First of all,the structure design of mechanical leg of quadruped robot and its motion characteristics analysis.Based on the physiological structure characteristics of dogs and considering the motion rules of the segments and joints of the mechanical leg that gotten from filming the labrador in different movements,the mechanical leg structure design was determined.On the basis of structure,the foot working space and the angle of motor driving were gotten from the forward kinematics and inverse kinematics analysis,and then the foot trajectory of the mechanical leg was planned based on the Trot gait sequence characteristics and composite cycloid.Second,control system design of the mechanical leg of quadruped robot.BLDCM was chosen as the joints driver of the control system and the dual closed-loop PID control algorithm was designed,including the speed loop and current loop,and the responding speed.The stability and the anti-jamming of the control system were verified by the simulation results.Then,the hardware circuit and software program of the control system design were completed respectively,in order to realize the expectations of the motor control.Finally,the control system performance test and motion experiment of the mechanical leg.The control system function of the mechanical leg and the planning motion experiment of the mechanical leg have been done successively,and the experimental results were in line with the expectations,that proved the validity of the control system design of mechanical leg and the rationality of the planning motion in this paper.The research results of this paper laid the foundation of structure design and control system of the quadruped robot for the follow-up research,and it had important referenced significance for the development and research of quadruped robot.