Dimensioning and evaluation of the elastic element in a Variable Torsion Stiffness actuator

Schuy, J.; Beckerle, Philipp; Faber, Jan; Wojtusch, Janis; Rinderknecht, Stephan; Stryk, Oskar von

doi:10.1109/aim.2013.6584356

Cited by 11 publications

(3 citation statements)

References 7 publications

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“…Stiness variation based on the length of the elastic element or equivalently, in the case of helical springs, on the number of coils is probably the simplest and most versatile out of these three options. It has been implemented on designs with helical springs (Hollander et al, 2005), torsion rods (Schuy et al, 2013) and, most commonly, leaf springs (Morita and Sugano, 1995;Choi et al, 2011;Braun et al, 2016;Fang and Wang, 2018). Note that all examples listed here, except for Braun et al (2016), employ a series spring and not a parallel spring as in this work.…”

Section: Variable Stiness Conceptsmentioning

confidence: 99%

Improving the performance of industrial machines with variable stiffness springs

Verstraten

López-García

Lenaerts

et al. 2020

Mechanics Based Design of Structures and Machines

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In several industrial applications, drivetrains impose highly dynamic oscillating motions to inertial loads. By introducing springs, the system's natural frequencies can be matched to the required operating frequencies, lowering energy consumption of the drivetrain. However, xed-stiness springs only have a positive eect in a limited range of frequencies. To solve this problem, variable stiness springs are proposed.A discussion of the eect of the series and parallel topology, as well as the possibility of adapting the spatio-temporal characteristics of the motion to the spring, is presented. Furthermore, a practical implementation of a variable stiness spring is proposed. Its eectiveness is validated in experiments.

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Section: Variable Stiness Conceptsmentioning

confidence: 99%

Improving the performance of industrial machines with variable stiffness springs

Verstraten

López-García

Lenaerts

et al. 2020

Mechanics Based Design of Structures and Machines

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“…Considering the structure-controlled stiffness of the VTS-actuator , the active length q s of the elastic element is adjusted by moving the counter bearing depicted in Figure 1 with Actuator 2. The elastic element is implemented as a torsional rod [26,27] and its stiffness characteristics are represented by…”

Section: Stiffness Controlmentioning

confidence: 99%

Stiffness Control of Variable Serial Elastic Actuators: Energy Efficiency through Exploitation of Natural Dynamics

2017

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Variable elastic actuators are very promising for applications in physical human-robot interaction. Besides enabling human safety, such actuators can support energy efficiency, especially if the natural behavior of the system is exploited. In this paper, the power and energy consumption of variable stiffness actuators with serial elasticity is investigated analytically and experimentally. Besides the fundamental mechanics, the influence of friction and electrical losses is discussed. A simple but effective stiffness control method is used to exploit the corresponding knowledge of natural dynamics by tuning the system to antiresonance operation. Despite nonlinear friction effects and additional electrical dynamics, the consideration of the ideal mechanical dynamics is completely sufficient for stiffness control. Simulations and experiments show that this yields a distinct reduction in power and energy consumption, which underlines the suitability of the control strategy.

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“…Several working principles for actuators with variable-stiffness capabilities have been proposed for various robotic applications. Examples of these are the Compliant Asymmetric Antagonistic Actuator (Roozing et al, 2015), vsaUT-II (Groothuis et al, 2014), AwAS-II (Jafari et al, 2012), Variable Torsion Stiffness Actuator Schuy et al (2013), Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator (MACCEPA) (Van Ham et al, 2007), and ARES (Cestari et al, 2015). Because of the importance of multi-DoF joints in the human body, bio-inspired robotic applications often require multi-DoF actuated joints (Mizuuchi et al, 2007; Potkonjak et al, 2011; Nakanishi et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

A Variable Stiffness Actuator Module With Favorable Mass Distribution for a Bio-inspired Biped Robot

et al. 2019

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Achieving human-like locomotion with humanoid platforms often requires the use of variable stiffness actuators (VSAs) in multi-degree-of-freedom robotic joints. VSAs possess 2 motors for the control of both stiffness and equilibrium position. Hence, they add mass and mechanical complexity to the design of humanoids. Mass distribution of the legs is an important design parameter, because it can have detrimental effects on the cost of transport. This work presents a novel VSA module, designed to be implemented in a bio-inspired humanoid robot, Binocchio, that houses all components on the same side of the actuated joint. This feature allowed to place the actuator's mass to more proximal locations with respect to the actuated joint instead of concentrating it at the joint level, creating a more favorable mass distribution in the humanoid. Besides, it also facilitated it's usage in joints with centralized multi-degree of freedom (DoF) joints instead of cascading single DoF modules. The design of the VSA module is presented, including it's integration in the multi-DoFs joints of Binocchio. Experiments validated the static characteristics of the VSA module to accurately estimate the output torque and stiffness. The dynamic responses of the driving and stiffening mechanisms are shown. Finally, experiments show the ability of the actuation system to replicate the envisioned human-like kinematic, torque and stiffness profiles for Binocchio.

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Dimensioning and evaluation of the elastic element in a Variable Torsion Stiffness actuator

Cited by 11 publications

References 7 publications

Improving the performance of industrial machines with variable stiffness springs

Improving the performance of industrial machines with variable stiffness springs

Stiffness Control of Variable Serial Elastic Actuators: Energy Efficiency through Exploitation of Natural Dynamics

A Variable Stiffness Actuator Module With Favorable Mass Distribution for a Bio-inspired Biped Robot

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