Design And Experiment Of A Fuzzy PID-based Hydro-electric Servo Controller For Legged Robot’s Leg

Due to its flexibly-moving capability and highly environmental adaptability,bio-inspired quadruped robot has been widely applied in the fields of military operations,geographical exploration etc. In order to realize the high load and high dynamic ability ofquadruped robot, more and more scientists choose the hydraulic actuation as the maindrive, for which has advantages in high power density ratio, fast response, impactresistance.Leg prototype is the base of hydraulic quadruped robot. In this thesis, some relatedresearch is carried on centering on the construction of the test bench for leg prototype,and issues concerning hydro-electric system servo control. Last but not least, a FuzzyPID controller is designed for further simulation and experimental verification. The maincontents are as follows:To start with a brief introduction of the mechanical structure and hydraulic system ofleg prototype, hydro-electric servo control system is later designed within the NI-PXIhardware platform, following by preliminary work like calibration of each component.The mentioned control program for the experiments is written with LabVIEW.The transfer function of the valve controlling hydraulic cylinder position servocontrol system and the force servo control system are established based on the modelingand analysis of valve controlling asymmetric cylinder unit, which provides a systemmodel for following simulation. In the meanwhile, the limitations are pointed out thatthere is a certain gap between the simulation model and the real one.A Fuzzy PID controller is designed and applied in the simulation study against theuncertainties existing in hydro-electric servo control system such as time delay,nonlinearity. It turns out that the Fuzzy PID controller is superior to the ordinary PID one.Hydro-electric servo experiments under the control of cylinder and leg prototypeprove the validity of the Fuzzy PID controller and the rationality of the hydro-electricservo control system, which meet the motion requirements of the project.