Finite-time disturbance reconstruction and robust fractional-order controller design for hybrid port-Hamiltonian dynamics of biped robots

In this paper, disturbance reconstruction and robust trajectory tracking control of biped robots with hybrid dynamics in the port-Hamiltonian form is investigated. A new type Hamiltonian function introduced, which ensures finite-time stability closed-loop system. The proposed system consists two loops: an inner outer loop. fractional proportional-integral-derivative filter used to achieve convergence for position errors at fractional-order sliding mode controller acts as a centralized inner-loop, ensuring velocity error. loop, undesired effects unknown external parameter uncertainties are compensated using estimators. Two estimators envisioned. former designed calculus. latter adaptive estimator, it constructed general dynamic robots. Stability analysis shows that stable both contact-less impact phases. Simulation studies on types (i.e., two-link walker RABBIT robot) demonstrate controller's performance rejection capability.