Rendering of arbitrary and stable stiffness using a series elastic actuator
Journal Volume
2020-July
Start Page
960
End Page
965
ISBN (of the container)
9781728167947
Date Issued
2020
Author(s)
Lee, Yushen
Abstract
Accurate and stable stiffness control is required for robots that need to interact safely with human or the environment. Accurate stiffness control can be achieved using a series elastic actuators (SEA). An SEA includes an elastic spring in series with an actuator to provide more accurate force control than conventional rigid actuators. Although impedance and admittance controllers have both been developed for series elastic actuators to render virtual stiffness, the stable virtual stiffness is still largely limited by the stiffness of the elastic spring in the SEA. Increasing the stiffness of the spring can allow a larger range of stable virtual stiffness. However, the accuracy of the stiffness control would be compromised. Adding a virtual damper can also improve the stability, but the stability range would highly depend on the environmental parameters. To overcome the limitations, this paper proposes a novel control strategy such that the stable range of the virtual stiffness does not depend on the spring stiffness and the environmental parameters. Both impedance and admittance controllers will be modified based on this new control strategy. The stability analysis of the modified controllers will show that the virtual stiffness can be arbitrarily selected and is unrelated to the spring stiffness and environmental parameters. It is expected that the new control strategy can be used for SEAs when wide-range and accurate virtual stiffness is required.
Event(s)
2020 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM 2020
Subjects
Admittance Control
Impedance Control
Series Elastic Actuator
Stability Analysis
Virtual Stiffness
Actuators
Controllers
Intelligent Mechatronics
Springs (components)
Control Strategies
Elastic Springs
Environmental Parameter
Series Elastic Actuators
Spring Stiffness
Stability Analysis
Stiffness Control
Virtual Stiffness
Stiffness
Publisher
Institute of Electrical and Electronics Engineers Inc.
Description
2020 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM 2020. Boston; MA. conference code:162314
Type
conference paper