
Fractional-order controller for bipeds
A paper published in the Robotics and Autonomous Systems journal.
A paper published in the Robotics and Autonomous Systems journal.
In this paper, disturbance reconstruction and robust trajectory tracking control of biped robots with hybrid dynamics in the port-Hamiltonian form is investigated. A fractional proportional-integral-derivative filter is used to achieve finite-time convergence for position tracking errors. A fractional-order sliding mode controller acts as a centralized controller, ensuring the finite-time stability of the velocity tracking error. Two disturbance estimators are envisioned. Stability analysis shows that the closed-loop system is finite-time stable in both contact-less and impact phases.
A paper published in the Mechanism and Machine Theory journal.
This paper presents an estimator of external disturbances for legged robots, based on the system’s momentum. The estimator, along with a suitable motion planner for the trajectory of the robot’s center of mass and an optimization problem based on the modulation of ground reaction forces, devises a whole-body controller for the robot. The designed solution is tested on a quadruped robot within a dynamic simulation environment. The quadruped is stressed by external disturbances acting on stance and swing legs indifferently.
A paper published in the IEEE Transactions on Robotics.
This article proposes a shared-control teleoperation architecture for robot manipulators transporting an object on a tray. We consider the case in which the object can break its contact with the robot end-effector. The proposed shared-control approach automatically regulates the remote robot motion commanded by the user and the end-effector orientation to prevent the object from sliding over the tray. Furthermore, the human operator is provided with haptic cues informing about the discrepancy between the commanded and executed robot motion.