Design of Series-Elastic Actuators for Dynamic Robots With Articulated Legs

2008 ◽  
Vol 1 (1) ◽  
Author(s):  
Simon Curran ◽  
Brian T. Knox ◽  
James P. Schmiedeler ◽  
David E. Orin
Keyword(s):  
Robotic Systems ◽  
Design Parameters ◽  
Motor Speed ◽  
Comprehensive Understanding ◽  
Complex Dynamic ◽  
Lift Off ◽  
The Moment ◽  
Series Elastic Actuators ◽  
Thrust Performance ◽  
Series Elastic

A series-elastic actuator (SEA) can provide remarkable performance benefits in a robotic system, allowing the execution of highly dynamic manuevers, such as a jump. While SEAs have been used in numerous robotic systems, no comprehensive understanding of an optimal design exists. This paper presents a new analytical basis for maximizing an SEA thrust performance for jumping from rest with an articulated leg. The analytical SEA model is validated with simulation and experimental results from a prototype leg. An SEA decouples the dynamic limitations of a dc motor actuator from the joint, allowing larger lift-off velocities than with a directly driven joint. A detailed analysis of the complex dynamic response of an SEA during the thrust phase leads to a new maximum impulse criterion, where motor speed is approximately half the no-load speed at the moment of peak motor torque. The analytical model and this proposed criterion are used to develop a simple equation for selecting SEA design parameters. Lastly, a novel unidirectional SEA design is presented that allows for accurate positioning of the leg during flight.

Analysis and Optimization of a Series-Elastic Actuator for Jumping in Robots With Articulated Legs

2008 ◽  
Author(s):  
Simon Curran ◽  
David E. Orin ◽  
Brian T. Knox ◽  
James P. Schmiedeler
Keyword(s):  
Detailed Analysis ◽  
Design Equation ◽  
Motor Speed ◽  
Complex Dynamic ◽  
Analytical Design ◽  
Series Elastic Actuator ◽  
Simulation Results ◽  
The Moment ◽  
Elastic Elements ◽  
Series Elastic

This paper presents the analysis and optimization of a series-elastic actuator (SEA) for jumping with an articulated leg. Analytical and simulation results are validated with experimental results from a prototype leg. Similar to the series-elastic elements in muscles, an SEA decouples the dynamic limitations of a DC actuator from the joint, allowing larger liftoff velocities than with a directly driven joint. Detailed analysis of the complex dynamic SEA response during the thrust phase yields insights into its performance. The maximum impulse occurs when the motor speed is approximately half the no-load speed at the moment of peak motor torque. This proposed criterion is used to develop a simple analytical design equation for an optimal SEA.

scholarly journals Parameter identification of robotic systems with series elastic actuators

2010 ◽  
Vol 43 (14) ◽  
pp. 350-355 ◽  
Author(s):  
Pieter van Zutven ◽  
Dragan Kostić ◽  
Henk Nijmeijer
Keyword(s):  
Parameter Identification ◽  
Robotic Systems ◽  
Series Elastic Actuators ◽  
Series Elastic

Hopping frequency influences elastic energy reuse with joint series elastic actuators

2021 ◽  
Vol 119 ◽  
pp. 110319
Author(s):  
A. Mohammadi Nejad Rashty ◽  
M. Grimmer ◽  
A. Seyfarth
Keyword(s):  
Elastic Energy ◽  
Series Elastic Actuators ◽  
Series Elastic

scholarly journals Design, modeling, and demonstration of a new dual-mode back-assist exosuit with extension mechanism

2021 ◽  
Vol 2 ◽  
Author(s):  
Erik P. Lamers ◽  
Karl E. Zelik
Keyword(s):  
Biomechanical Model ◽  
Mode Switching ◽  
Design Parameters ◽  
Dual Mode ◽  
Extension Mechanism ◽  
Body Forces ◽  
Low Profile ◽  
Military Healthcare ◽  
The Moment ◽  
Practical Factors

Abstract Occupational exoskeletons and exosuits have been shown to reduce muscle demands and fatigue for physical tasks relevant to a variety of industries (e.g., logistics, construction, manufacturing, military, healthcare). However, adoption of these devices into the workforce has been slowed by practical factors related to comfort, form-factor, weight, and not interfering with movement or posture. We previously introduced a low-profile, dual-mode exosuit comprised of textile and elastic materials to address these adoption barriers. Here we build upon this prior work by introducing an extension mechanism that increases the moment arm of the exosuit while in engaged mode, then collapses in disengaged mode to retain key benefits related to being lightweight, low-profile, and unobstructive. Here we demonstrate both analytically and empirically how this extensible exosuit concept can (a) reduce device-to-body forces (which can improve comfort for some users and situations), or (b) increase the magnitude of torque assistance about the low back (which may be valuable for heavy-lifting jobs) without increasing shoulder or leg forces relative to the prior form-fitting exosuit. We also introduce a novel mode-switching mechanism, as well as a human-exosuit biomechanical model to elucidate how individual design parameters affect exosuit assistance torque and device-to-body forces. The proof-of-concept prototype, case study, and modeling work provide a foundation for understanding and implementing extensible exosuits for a broad range of applications. We envision promising opportunities to apply this new dual-mode extensible exosuit concept to assist heavy-lifting, to further enhance user comfort, and to address the unique needs of last-mile and other delivery workers.

A convex optimization framework for robust-feasible series elastic actuators

Mechatronics ◽  
2021 ◽  
Vol 79 ◽  
pp. 102635
Author(s):  
Edgar A. Bolívar-Nieto ◽  
Tyler Summers ◽  
Robert D. Gregg ◽  
Siavash Rezazadeh
Keyword(s):  
Convex Optimization ◽  
Optimization Framework ◽  
Series Elastic Actuators ◽  
Series Elastic
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