The stiffness - the change in resistive force that counteracts the effect of external loads - is substantially dependent on variability in limb geometry and orientation, and on antagonist muscles co-contraction. The control of joint impedance provides mechanical stability in presence of external perturbations and this is the reason why active modulation of limb impedance by the central nervous system (CNS) is considered an essential part of effective motor control.

People: Angelo Emanuele Fiorilla, Nikos.G.Tsagarakis, Francesco Nori, Giulio Sandini

Extended finger and Exoskeleton linkage simulation models							Exoskeleton Design: the indication text shows the main parts of the device
EMG electrodes							Optotrak Certus MoCap system

The aims of this study are:
• The design of a device to perform measurement of the stiffness of the thumb and of the index finger at the MCP joint during flexion and extension movements in a reach-to-grasp task;
• The identification of a relationship between the electrical activity of the antagonist muscles of the forearm and the stiffness of the fingers.
• The main steps of the project’s development will consist in: Design and develop a hand exoskeleton to over-impose and measure a displacement on the finger’s MCP joint and of the proper control hardware and software platforms;
• Track the relative position of the hand with respect to the grasped object;
• Identify the effectual number and location of EMG sources of the forearm skin;
• Integrate the EMG device with the exoskeleton’s control system.