Energy control for complex pendulums based on tracking of online computed force trajectories

In this paper we propose to track online computed force trajectories to control the energy of various types of pendulum-like objects. The considered pendulum-like objects can be controlled by multiple agents and swing in different oscillation degrees of freedom. Our goal is to excite one specific oscillation, the intended oscillation, while damping all other disturbance oscillations. By approximating the intended oscillation as a simple pendulum oscillation, we can specify a desired force trajectory. Tracking of this force trajectory results in a controlled swing-up of the intended oscillation accompanied by a simultaneous damping of the disturbance oscillations. Simulation experiments with a two-agent trapezoidal pendulum show convincing control performance. A human-robot virtual reality experiment shows the transferability of the control approach to a human interaction partner. The limitations of the approach are discussed based on simulation results obtained for a single-agent double pendulum.