Admittance and impedance control for industrial robots

Type of thesis: 

Master

Reference: 

Ott et al. "A hybrid system framework for unified impedance and admittance control." Journal of Intelligent & Robotic Systems 2015

Starting Data: 

01.09.2017

Abstract/Topic : 

To provide a compliant manipulator behavior, which adjusts to changing environment conditions, the regulation of position, force or velocity is an inadequate approach. Impedance Control provides a good performance when the environment is stiff but results in poor accuracy when the environment is soft. In contrast, Admittance Control provides proper performance for soft environments but results in contact instability for stiff environments. In other words, the impedance control satisfies in stiff environments while admittance control does in soft environment.
A pure force control results in inaccuracy in free space due to the lack of force-feedback. While, with position control only, unexpected contact situations may lead to damage or, even worse, injuries as a result of no tactile feedback. The contact situations remain undetected and the manipulator follows its positioning task. To avoid that, it is necessary to control its dynamic behavior instead.
Following the mentioned motivation, this master thesis aims at implementing impedance and admittance controllers on an industrial robot (Stäubli robot). The implementation is expected to be very modular using the Orocos-Gazebo framework with the possibility of adapting easily on other robots such as KUKA-lwr. The possibility of switching/blending between impedance and admittance mode will be investigated too.

Required Qualification: 

Knowledge of robot control and appetite to learn more in that direction; programming skills in C++