Influence of loads and design parameters on the closed-loop performance of Series Elastic Actuators

2016 ◽  
Author(s):  
Steffen Schutz ◽  
Atabak Nejadfard ◽  
Karsten Berns
Keyword(s):  
Closed Loop ◽  
Design Parameters ◽  
Series Elastic Actuators ◽  
Series Elastic

scholarly journals Requirement derivation method for a legged robot with series-elastic actuators

2020 ◽  
Author(s):  
Daniela Vacarini De Faria ◽  
Marcos Máximo ◽  
Luiz Góes
Keyword(s):  
Stance Phase ◽  
Sampling Method ◽  
Closed Loop ◽  
Inverted Pendulum ◽  
Legged Robot ◽  
Task Execution ◽  
Derivation Method ◽  
Series Elastic Actuators ◽  
Slip Method ◽  
Series Elastic

In this work we propose a new methodology for requirement derivation of the dynamical requirements of a series elastic actuator applied to a legged robot. The leg model consists of a mechanism composed of three links – representing the thigh, the shin and the foot – and two Series Elastics Actuators (SEA) – representing the knee and ankle. The stance phase of a running gait is modeled according to the Spring Loaded Inverted Pendulum (SLIP) method. To make sure that sufficient extent of running patterns is covered, the SLIP parameters are sampled inside a predefined range using the Improved Distributed Hypercube Sampling method. The number of samples used in this study is selected through a convergence test. The leg performance is then studied through a comparison between the CoM trajectory obtained simulating the mechanism with ideal actuators on its joints and with SEAs. A closed loop Impedance Controller is used to calculate the torque required by each joint that allows the system to behave as a spring, thus mimicking the spring-like behavior of the leg during the SLIP movement. The SEAs are modeled by a parametric transfer function that is also presented in this work. To the best of our knowledge, this work is the first to propose a method that accounts for the performance of this task execution.

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.

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

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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