| Quadruped robot shows great application prospect in numerous areas for its discreteusage of ground support. High load capacity, good dynamic response and high environmentaladaptability are not only the precondition of quadruped robot’s employment in reality but alsothe current focus in the mobile robot research area. The design and control of the hydraulicsystem is the basic technology of high-performance quadruped robot. With its advantages inhigh output force, high power density ratio, impact resistance, hydraulic drive has become themain drive type to guarantee the motion performance of robot with high speed and heavy load.However, the design and servo control of hydraulic system is one of the key common issuesfor such robots.In this thesis, some related research work is carried out according to the requirements ofthe drive system of high-performance quadrupled robot: a hydraulic system is designed forquadruped robot, the mathematical model of valve-cylinder unit is established and identifiedand electro-hydraulic position servo control method is studied.The complex working conditions are analyzed and the requirements of the hydraulicsystem are determined accordingly. Therefore, the critical parameters of hydraulic system arecalculated. Then, the scheme design, selection calculations of key hydraulic components,layout and integration of them are accomplished.The dead zone characteristics of valve controlling asymmetric hydraulic cylinder unit arestudied and its mathematical models are established. Further, the dead zone compensation andsystem identification experiments are carried out on the experimental platform with a singlecylinder.Considering the characteristics of hydraulic system such as time delay, strongnonlinearity and time-varying load etc., a fuzzy PID controller is designed with PID and fuzzycontrol algorithm adopted. Then, step, sine and triangular wave signals tracking isimplemented based on this algorithm.A quadruped robot control experiment system is constructed with LabVIEW and NI-PXIwhich is used as control core. Trajectory tracking, vertical jumping, squatting and walkingwith single foot gait experiments are designed and implemented on the prototype platforms.The experimental results show that the hydraulic system and the control algorithms both meetthe motion requirements of the quadruped robot.Research results of this thesis provide a complete design thought for design of high-performance hydraulic drive unit, and is expected to be extended for the outdoor quadrupedrobot in the future, having potential application values. |
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