Energy-Based Control of an Underactuated Quadrotor using a Geometrical Spring-Damper approach


Jelmer Graat
Presentation MSc presentation
Date 2018-02-19
Time 16:00
Location Carré 2G

Nowadays, robots are getting more common in everyday life where it is necessary to interact with the environment which is in general unknown. For guaranteed safe interaction, the energy in the system should be considered explicitly. Using energy-based control, virtual dynamics are added to the plant such that the desired dynamics are achieved.

 

An energy-based controller using a virtual spring-damper has been developed for a underactuated quadrotor. A virtual spring with a Remote Center of Compliance (RCC) is presented to induce a coupling between the error in the underactuated plane and the quadrotor tilting torque. To guarantee safe interaction, the controller should be passive. It is shown that passivity is destroyed by the projection of the control wrench on the subspace of implementable wrenches if done naively. An energy-tank is proposed to recover passivity.

 

Simulations and experiments have been performed to study the passivity and the behavior of the controller. It has been concluded that underactuation and the rotor dynamics are problematic for the passivity of the controller. Furthermore, with the currently available quadrotor hardware it is only possible to approximate energy-based control. However, RCC-based control is found to be promising, especially for interaction control.

Posted on Wednesday, December 6, 2017