scholarly journals Adaptive Torque and Position Control for a Legged Robot Based on a Series Elastic Actuator

10.5772/62204 ◽  
2016 ◽  
Vol 13 (1) ◽  
pp. 26 ◽  
Author(s):  
Qiuguo Zhu ◽  
Yichao Mao ◽  
Rong Xiong ◽  
Jun Wu
Keyword(s):  
Position Control ◽  
Legged Robot ◽  
Series Elastic Actuator ◽  
Series Elastic

A Unidirectional Series-Elastic Actuator Design Using a Spiral Torsion Spring

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Brian T. Knox ◽  
James P. Schmiedeler
Keyword(s):  
Position Control ◽  
Biped Robot ◽  
Legged Robots ◽  
Torsion Spring ◽  
Series Elastic Actuator ◽  
Electromechanical Actuation ◽  
Torsion Springs ◽  
Actuator Design ◽  
Rotational Direction ◽  
Series Elastic

This paper presents a novel series-elastic actuator (SEA) design that uses a spiral torsion spring to achieve drivetrain compliance in a compact and efficient mechanism. The SEA utilizes electromechanical actuation and is designed for use in the experimental biped robot KURMET for investigating dynamic maneuvers. Similar to helical torsion springs, spiral torsion springs are particularly applicable for legged robots because they preserve the rotational motion inherent in electric motors and articulated leg joints, but with less drivetrain backlash and unwanted coil interaction under load than helical torsion springs. The general spiral torsion spring design equations are presented in a form convenient for robot design, along with a detailed discussion of the mechanism surrounding the spring. Also, the SEA mechanism has a set of unidirectional hardstops that further improves the position control by allowing series-elasticity in only one rotational direction.

An improved IDA-PBC method with link-side damping injection and online gravity compensation for series elastic actuator

2021 ◽  
pp. 095440622110084
Author(s):  
Jiexin Zhang ◽  
Pingyun Nie ◽  
Bo Zhang
Keyword(s):  
Position Control ◽  
Friction Compensation ◽  
Gravity Compensation ◽  
Control Performance ◽  
Residual Vibration ◽  
Series Elastic Actuator ◽  
In Series ◽  
Passivity Based Control ◽  
Two Degree Of Freedom ◽  
Series Elastic

Elastic elements in series elastic actuator (SEA) will cause residual vibration in position control. Incorporating link-side damping injection and friction compensation, we propose an improved interconnection and damping assignment passivity-based control (IDA-PBC+) method to suppress residual vibration. Damping on the motor side and link side can be adjusted simultaneously. In addition, the desired motor-side trajectory planning and online gravity compensation are also introduced to improve control performance and steady-state accuracy. The effectiveness of the proposed method in suppressing residual vibration is experimentally verified with a two-degree-of-freedom SEA device.

A Fixed Structure Gain Selection Strategy for High Impedance Series Elastic Actuator Behavior

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Kenan Isik ◽  
Gray Cortright Thomas ◽  
Luis Sentis
Keyword(s):  
Position Control ◽  
Controller Design ◽  
Selection Strategy ◽  
Impedance Bandwidth ◽  
Phase Margin ◽  
Ideal Model ◽  
Series Elastic Actuator ◽  
High Impedance ◽  
Position Controller ◽  
Series Elastic

Series elastic actuators (SEA) are widely used for impact protection and compliant behavior, but they typically fall short in tasks calling for accurate position control. In this paper, we propose a simple and effective heuristic for tuning series elastic actuator controllers to a high impedance position control behavior, which compares favorably with previous publications. Our approach considers two models, an ideal model and a nonideal model with time delays and filtering lag. The ideal model is used to design cascaded proportional-derivative (PD)-type outer impedance and inner force loops as a function of critically damped closed-loop poles for the force and impedance loops. The nonideal model provides an estimate of the phase margin of the position controller for each candidate controller design. A simple optimization algorithm finds the best high-impedance behavior for which the nonideal model meets a desired phase margin requirement. In this way, the approach automates the trade-off between force and impedance bandwidth. The effect of important system parameters on the impedance bandwidth is also analyzed and the proposed method verified with a physical actuator.

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