scholarly journals Robust Force Control of Series Elastic Actuators

Actuators ◽  
2014 ◽  
Vol 3 (3) ◽  
pp. 182-204 ◽  
Author(s):  
Andrea Calanca ◽  
Luca Capisani ◽  
Paolo Fiorini
Keyword(s):  
Force Control ◽  
Series Elastic Actuators ◽  
Series Elastic

Experimental Validation of Unlumped Model and its Design Implications for Rotary Series Elastic Actuators

2017 ◽  
Author(s):  
Jeong H. Yoon ◽  
Daniel Sun ◽  
Vidur Sanandan ◽  
Dennis Hong
Keyword(s):  
Force Control ◽  
Experimental System ◽  
Open Loop ◽  
Design Guidelines ◽  
Trial And Error ◽  
Dynamic Simulations ◽  
Actuator Dynamics ◽  
Selection For ◽  
Series Elastic Actuators ◽  
Series Elastic

Series Elastic Actuators (SEA) have been in development for multiple decades. In spite of this, few design guidelines exist and stiffness selection for the compliant element still remains a trial-and-error process. In this paper, we experimentally validated the unlumped model first proposed by Orekhov for Rotary SEA (RSEA) and outlined a design methodology for selecting the spring stiffness based on the open loop force control bandwidth of unlumped model for series elastic actuators. We modified the unlumped model to apply to Rotary SEAs. Through experimental system identification, we demonstrated that our new unlumped model for RSEA is a valid model of actuator dynamics. Additionally, we recommended design guidelines for RSEA to achieve desired force control bandwidth based on the pure torque source assumption. An example of the design process was given and actuator performance was verified through dynamic simulations in ADAMS.

Force Control of Robot Fingers using Series Elastic Actuators

2012 ◽  
Vol 18 (10) ◽  
pp. 964-969 ◽  
Author(s):  
Seung-Yup Lee ◽  
Byeong-Sang Kim ◽  
Jae-Bok Song ◽  
Soo-Won Chae
Keyword(s):  
Force Control ◽  
Series Elastic Actuators ◽  
Series Elastic

Configurable Compliance for Series Elastic Actuators

2013 ◽  
Author(s):  
Viktor Orekhov ◽  
Derek Lahr ◽  
Bryce Lee ◽  
Dennis Hong
Keyword(s):  
Force Control ◽  
Joint Stiffness ◽  
Variable Stiffness ◽  
Effective Length ◽  
In Series ◽  
Primary Advantage ◽  
Variable Compliance ◽  
Natural Dynamics ◽  
Series Elastic Actuators ◽  
Series Elastic

Variable compliance has been a growing topic of interest in legged robotics due to recent studies showing that animals adjust their leg and joint stiffness to adjust their natural dynamics and to accommodate changes in their environment. However, existing designs add significant weight, size, and complexity. Series Elastic Actuators, on the other hand, are designed with a set stiffness usually tuned for actuator performance. We propose a new concept for implementing a physical spring in series with a linear SEA using a cantilevered spring. A movable pivot is used to adjust the stiffness by changing the effective length of the cantilever. While the proposed design does not allow for variable compliance, it does retain many of the benefits of passive spring elements such as absorbing impacts, storing energy, and enabling force control. The primary advantage of the design is the ability to adjust the stiffness of each joint individually without the increased weight and complexity of variable stiffness designs. This paper introduces the motivation for configurable compliance, describes the proposed design concept, explains the design methods, and presents experimental data from a completed prototype.

scholarly journals A Sliding Mode Force and Position Controller Synthesis for Series Elastic Actuators

Robotica ◽  
2019 ◽  
Vol 38 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Emre Sariyildiz ◽  
Rahim Mutlu ◽  
Haoyong Yu
Keyword(s):  
Force Control ◽  
Dynamic Models ◽  
Position Control ◽  
Sliding Mode ◽  
Dynamic Environment ◽  
Industrial Robots ◽  
Motion Controller ◽  
Mismatched Disturbances ◽  
Series Elastic Actuators ◽  
Series Elastic

SummaryThis paper deals with the robust force and position control problems of series elastic actuators (SEAs). It is shown that an SEA’s force control problem can be described by a second-order dynamic model which suffers from only matched disturbances. However, the position control dynamics of an SEA is of fourth order and includes matched and mismatched disturbances. In other words, an SEA’s position control is more complicated than its force control, particularly when disturbances are considered. A novel robust motion controller is proposed for SEAs by using disturbance observer (DOb) and sliding mode control. When the proposed robust motion controller is implemented, an SEA can precisely track desired trajectories and safely contact with an unknown and dynamic environment. The proposed motion controller does not require precise dynamic models of environments and SEAs. Therefore, it can be applied to many different advanced robotic systems such as compliant humanoids, industrial robots and exoskeletons. The validity of the proposed motion controller is experimentally verified.

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