It is well-known that humans are able to change the mechanical impedance of their locomotion system voluntarily based on short- and long-term reflexes. To evaluate these, we have devised built different contraptions to measure human impedance.The idea behind these measurements is to analyze impedance regulation for the exploitation in new generations of robots with mechanical variable impedance. To this end we so have mainly concentrated on human arm and finger impedance.

We have built a new setup for measuring human leg impedance, consisting of two linear motors and two force-torque sensors to perturb the human legs in stance. By also measuring muscular activity using surface EMG, we can model how human stabilise at different perturbation frequencies, and how impedance regulation is done. Initial proof-of-concept measurements have to be extended by setting up a model of the perturbed system, measuring joint positions and velocities, and so on. Measuring the position and the force plus EMG will allow us in future to analyse the behaviour of leg impedance within the spinal circuitry feedback loops.

Your thesis will include the following tasks:

• literature search
• implement a method to fix the properties of the kinematic chain (implementing already exsiting algorithms of the bionics group)
• develop a model of the human legs and the lower part of the body with fixed inertial properties
• calibrating joint impedance with EMG
• do continuous impedance measurements using EMG, e.g., during frequency run up of the linear motors