• Energy Research

Research on bipedal locomotion has shown that a dynamic walking gait is energetically more efficient than a statically stable one. Analogously, even though statically stable multi-wheeled robots are easier to control, they are energetically less efficient and have low accelerations to avoid tipping over. In contrast, the ballbot is an underactuated, nonholonomically constrained mobile robot, whose upward equilibrium point has to be stabilised by active control. In this work, we derive coordinate-invariant, reduced, Euler–Poincare equations of motion for the ballbot. By means of partial feedback linearisation, we obtain two independent passive outputs with corresponding storage functions and utilise these to come up with energy-shaping control laws which move the system along the trajectories of a new Lagrangian system whose desired equilibrium point is asymptotically stable by construction. The basin of attraction of this controller is shown to be almost global under certain conditions on the design of the mechanism which are reflected directly in the mass matrix of the unforced equations of motion. © 2016 Informa UK Limited, trading as Taylor & Francis Group

This paper studies the multi-waypoint-based path planning problem (MWPP) for redundant space robots. The end-effector of a space robot should visit a set of predefined waypoints with optimal distance, and the free-floating base should suffer minimum attitude disturbances from the manipulator during manoeuver. The MWPP is decomposed into two sub-problems: the problem of optimal waypoint-sequence and the problem of optimal joint-movements. First, the Hybrid Self-adaptive Particle Swarm Optimization algorithm is proposed for optimal waypoint-sequence. Second, an Improved Particle Swarm Optimization algorithm, combined with direct kinematics of the space robot, is proposed for optimal jointmovements. Finally, simulations are presented to validate the approach, including comparisons with other approaches.

In this brief, we propose a passivity-based control design for a rolling-balancing system called the disk-on-disk (DoD). The stabilization of the desired equilibrium is obtained via energy shaping and damping injection. The DoD is an underactuated mechanical system composed of two disks arranged one on top of the other. The top disk, which we call the object, is free to roll without slipping on the lower disk, which we call the hand. The hand is actuated by a controlled torque, while the object is unactuated. The control objective is to balance the object at the upright position and drive the hand to a desired angle. We design an energy shaping controller without solving the partial differential equations, which rise from the matching equation. We assess the performance of the controller by both simulations and experiment results, which also verify the practical applicability of the design approach.