1. Impedance Control

2. What is The Joint Impedance?
The Automatic Capability of the System to Resist an Applied Load before Voluntary Intervention Takes Place (Winters et al. 1988)
Stiffness is defined as the ratio of change in force or torque to change in length or angle
Viscosity is defined as the ratio of change in force or torque to change in velocity or angular velocity

4. Stiffness Control F = k ( X – X0) :رابطه يك فنر (عضله) K = σ (α )

6. How Joint Impedance May Be Control?
1- Nonlinear Muscle and Joint Prpperties.
2- Co-contractions
3- Reflexes and co-activation

9. Stiffness Control Hassan, 1986

10. Stiffness Control

12. Roughly Speaking, The Axis of Maximum stiffness is a Line that Connect The Hand to a Point between Shoulder and Half Way Through the Elbow
Mussa-Ivaldi et al. 1985

13. Adapted From Gomi & Osu 1998

14. Co-Contraction Increase The Mechanical Stability of The Joint But at Greater Metabolic Cost
Burdet et al. 2001

15. Experimental Setup Arm Configuration During The Experiment
Interactive Motion Technologies,
Cambridge MA

16. EPH Generalization