Research And Development Of Biped Robot With Heterogeneous Legs

Biped robot with two legs is a kind of advanced humanoid robots that can walk like human being and have ability of doing repetitive, hard and exact-need works instead of human being in his living environment. Now biped robot already can walk using two legs, but gait is not like human being's. In biomedicine rehabilitation field, the intelligent prosthesis controlled by micro-process unit is studied for amputee, and intelligent prosthetic above-knee limb can simulate human leg's moving and has humanoid knee joint. The gait of amputee with intelligent prosthetic limb is more like health people gait. It can improve biped robot to introduce the study methods and technologies of intelligent prosthesis into biped robot study. Human being's two legs and their gait are symmetrical in normal walking, but under lame or other knee trauma situation, two legs are heterogeneous. The walking with heterogeneous legs is advanced function of human being and should be studied.Integrating intelligent prosthesis and biped robot study, a new-style robot, biped robot with heterogeneous legs (BRHL) that is composed of a leg of normal biped robot, called artificial leg (AL), and an intelligent bionic leg (IBL), a kind of advanced intelligent prosthesis, is proposed. BRHL provide a good test-bed for study of intelligent bionic leg that has good bionic characteristics, and can be used to study the coordination between human being and intelligent limb, and the walking with heterogeneous legs.Following the meaning, contents and methods of BRHL study, the mechanism and form of BRHL is given. 4-bar closed-chain knee joint controlled by intelligent MR damper has polycentric characteristic of human knee joint. Optimization computation of 14 mechanism parameters of 4-bar knee joint is used to make it track human knee joint and damper cost minimum energy.Using division modeling method, the kinematics and Lagrangian dynamics models of artificial leg and intelligent bionic leg in stance phase and swing phase are built. Constraint conditions are different in stance and swing phase. According to the amount of general variables, general force and constraints, dynamics model's classification and solving methods are discussed. For sample waling, using crotch point motion as two legs' task object, the coordination dynamics model is established and coupling of two legs is analyzed. In order to walk like human being, the flexibility of prosthetic foot used for amputee must be considered and flexibility modeling method is studied.The master-slave dual-leg coordination control strategy is pointed, and is compared with dual-arm coordination control. For coordination control, three level hierarchial architecture control system is given. The key problem of master-slaver dual-leg coordination is the gait tracking of IBL to AL in reasonable phase difference. Considering the 4-bar knee joint is controlled by MR damper, IBL cannot follow arbitrary AL gait perfectly. So multi-variable optimization using SUMT algorithm is used to get optimal gait tracking which is a nonlinear, strong coupling, time-varying control problem. Computed torque with PD feedback control is studied and convergence is proved using...