Design And Implementation Of Distributed Hardware Architecture For Motor Driven Quadruped Robot

Motor driven quadruped robot has a great prospect in the fields of military-civilian material transportation,mineral exploration,disaster relief in a complex mountain-forest environment.Although there are many motor driven quadruped robot platforms at home and abroad,these platforms mainly focus on gait algorithm and mechanical structure,which lack of the research on hardware architecture.Based on the above reasons,this thesis carries out the research on hardware architecture of motor driven quadruped robot.The main work of this thesis is as follew:According to the research status of motor driven quadruped robot and the actual needs under the application scenario,this thesis proposed a distributed hardware architecture,which regards the robot single leg and power management system as the nodes of the distributed architecture.Meanwhile,I selected CAN bus as the communication mean of the communication link.The single leg control node includes sensors,joint drive units,and a hardware PCB,and the four legs of the robot are configured with the same single leg control node.Those sensors are used to acquire the motion state of the robot in real time.In this thesis,sensors with excellent performance are selected so that the robot can obtain the angles of joints,the pressure values of feet and the posture of body.Those datas can provide support for the upper layer algorithm.At the same time,by optimizing those sensors,the average error of the joint angle sensor is 0.03066 rad,and the minimum value of the Z-axis average error of the attitude sensor is 0.06 degree,which is less than 1%.The hardware PCB I designed is used to complete the servo control of motors and obtain sensors' datas,which includes microcontroller unit,power supply unit,CAN communication unit,signal conditioning unit and alarm unit.As for the power management system node,I compared the mainstream lithium batteries in terms of energy density,safety,service life and thermal stability,and selected ternary lithium as the power source of the robot.Then,I designed its' hardware PCB,which can provide up to 12 channels different stable voltages.According to the experimental datas,the output voltage fluctuation value is between 1.676 V and 2.633 V,which can ensure the stable operation of motors.Meanwhile,the electrical parameters are monitored in real time to prevent abnormal conditions from happening,such as overcurrent and overvoltage.As for the communication link,I made full use of the multi-master control,system softness and multi-point connection characteristics of CAN bus,and customized a set of efficient,scalable,low-latency communication protocol.This protocol reduces the transmission delay of the communication link to 2ms,which means that the control frequency of the robot can reach 500 Hz theoretically.This control frequency can fully meet the control requirements of the robot.Based on the above researches,the distributed hardware architecture I proposed in this thesis meets the expected demands of motor driven quadruped robot.Those researches can promote the application of the robot in a complex mountain-forest environment and lay a solid foundation for the further work.