Real-time damping estimation for variable impedance actuators

Recently-developed variable damping mechanisms have been exploited as a complement to compliant actuators. While accurate knowledge and control of generated damping is essential for achieving the desired performance, no physical sensor measuring the damping exists. This work introduces a novel non-model-based approach for the estimation of time-variant damping for variable impedance actuation systems. The approach is based only on torque and position/velocity measurements; without the knowledge of system's inputs, to ensure the estimation of both intentional and unintentional changes. Hence, a recursive least square estimator, modified for achieving a proper convergence for the estimation of time-variant parameters, is exploited. Experiments on a variable physical damping actuator are also presented to validate the performance of proposed approach.

Authors

• Navvab Kashiri
• Matteo Laffranchi
• Jinoh Lee
• Nikos G. Tsagarakis
• Lisha Chen
• Darwin G. Caldwell

Keywords

• Damping
• Torque
• Estimation
• Friction
• Torque measurement
• Force
• Actuators
• Dissipation
• Least-squares
• Prediction Error
• Cost Function
• Input Signal
• Output Signal
• Weighting Factor
• Estimation Algorithm
• Low Velocity
• Normal Force
• Digital Signal Processing
• Function Of Velocity
• Normalized Root Mean Square Error
• Viscous Damping
• System Damping
• Recursive Least Squares
• Linear Damping
• Damping Values
• Recursive Least Squares Algorithm
• Forgetting Factor
• Linear System
• Deflection Angle
• Design Parameters