Design And Research On Electro-hydraulic Control System Of Quadruped Robot

Nowadays, with the development of global modern technology, and the requirement ofthe market. Robotics technology has made great strides. Especially various types of militaryrobots are playing an increasingly important role in the field of national defense andgeopolitical strategy. In China’s vast western region, because of the complex terrain andrugged road, the traditional wheeled or tracked robots can not meet the requirements of theterrain passing ability. An urgent need to develop a kind of special legged robot with terrainadaptability. Compared with other types of legged robot, bionic quadruped robot can satisfyunstructured terrain conditions. Hydraulic drive bionic quadruped robot is a research focusdomestic and international in recent years. Electro-hydraulic servo control technology is oneof the most important part of hydraulic drive bionic quadruped robot’s keytechnology group.This article focuses on the design and research of electro-hydraulic servo control system ofthe hydraulic drive bionic quadruped robot.And made a series of useful results.This article based on hydraulic driven bionic quadruped robot developed by BeijingInstitute of Technology Special Robotics Innovation Center. Research process includes threeparts, theoretical exploration-Simulation-experimental verification. Multi-platform Co-simulation and modeling experiments was formed with LMS Virtual.Lab Motion, LMSImagine LabAMEsim and Matlab/Simulink, to find the characteristics and key technologyoffields of electro-hydraulic servo control that ensure the Stability of the robot. Distributedelectro-hydraulic servo control system architecture based on STM32F405/7was designed.The architecture appropriate to the highly symmetric structure and complex control tasks ofthe robot. The architecture composed of a motion controller and four servo controllers and aservo bus. Dual CAN bus based servo bus was designed, to separate the state feedback busand control instruction bus. And the servo command designed base on the CAN buscommunication protocol. Numerical noninverting input constant current source circuit wasdesigned with AD5724R and OPA547in the servo controller to drive the servo valve. Threemotion control algorithms was established, which involved kinematics algorithm,transformation algorithm from joint space to hydraulic cylinder stroke space and quinticspline path planning algorithm. A fuzzy adaptive PID control algorithm with asymmetricfeedforwardcompensationwas establishedto meet theelectro-hydraulicservocharacteristics.On the basis of the above work, performance verification experiments conducted on thehydraulic drive bionic quadruped robot physical prototypes developed by Beijing Institute of Technology Special Robotics Innovation Center. Experimental results show that thedistributed electro-hydraulic servo control system architecture designed in this paper canreliably complete the motion control and servo control tasks according to the desiredobjectives,andcantakeintoaccountthemulti-channelreal-timemotioncontrolrequirementsand single-channel high accuracy servo control requirements. The results also showed that,in the designed fuzzy adaptive PID control algorithm with asymmetric feedforwardcompensation, asymmetric feedforward parameters not only improving the symmetryproblem, but also help control system to better suppress the speed error. The work and theconclusions show that, the designed electro-hydraulic servo control system of the hydraulicdrive bionic quadruped robot in this article can stably, reliably, efficiently complete theexpected performance requirements, to achieve the desired overall design effect. The workand the conclusions has laid a solid foundation for further research practical application ofthe hydraulic driven bionic quadruped robot.