Conception and evaluation of a novel variable torsion stiffness for biomechanical applications

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

doi:10.1109/biorob.2012.6290778

Cited by 20 publications

(27 citation statements)

References 27 publications

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“…De and Tasch designed a two dof degree-of-freedom finger, which again uses leaf springs, but can also control the coupling stiffness [75]. In [76] a torsional elastic element with a relocatable counter bearing changes the active spring length.…”

Section: Active Spring Lengthmentioning

confidence: 99%

Variable impedance actuators: A review

Vanderborght

Albu-Schäffer²,

Bicchi

et al. 2013

Robotics and Autonomous Systems

834

522

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Variable Impedance Actuators (VIA) have received increasing attention in recent years as many novel applications involving interactions with an unknown and dynamic environment including humans require actuators with dynamics that are not well-achieved by classical stiff actuators. This paper presents an overview of the different VIAs developed and proposes a classification based on the principles through which the variable stiffness and damping are achieved. The main classes are active impedance by control, inherent compliance and damping actuators, inertial actuators, and combinations of them, which are then further divided into subclasses. This classification allows for designers of new devices to orientate and take inspiration and users of VIA's to be guided in the design and implementation process for their targeted application.

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Section: Active Spring Lengthmentioning

confidence: 99%

Variable impedance actuators: A review

Vanderborght

Albu-Schäffer²,

Bicchi

et al. 2013

Robotics and Autonomous Systems

834

522

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“…To implement and analyze the strategy on a variable torsion stiffness (VTS) actuator, the natural dynamics and energy consumption of the system are analyzed and related to each other as suggested in [8]. The analytical and experimental analyses show that the antiresonance operation is very suitable, which confirms the results from [8,9] on a system with different dynamical parameters, i.e., the VTS-actuator [13,26]. As in the previous studies, the influence of friction and electrical losses is investigated and has distinct impacts on power and energy consumption.…”

Section: Discussionmentioning

confidence: 54%

“…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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“…Based on the results of stiffness optimization, the list of requirements is updated. From that, a conceptual knee design of a powered knee device using variable torsion stiffness actuation as proposed in [24] is developed. To provide the required joint powers, a 3890048CR DC motor with a peak power of 406 W from Dr. Fritz Faulhaber GmbH & Co. KG, Schönaich, Germany is combined with a 38A series transmission that incorporates a reduction ratio of 60.…”

Section: B Systems Engineeringmentioning

confidence: 99%

Analyzing and considering inertial effects in powered lower limb prosthetic design

Beckerle¹,

Wojtusch²,

Seyfarth³

et al. 2015

2015 IEEE International Conference on Rehabilitation Robotics (ICORR)

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Powered lower limb prostheses are designed to restore the biomechanical functionality of missing parts of their users' bodies. However, they do not yet meet the versatility and efficiency of the biological counterpart. A crucial open issue is how the prosthetic system and its actuator should be designed to achieve an energy efficient operation. This paper proposes a novel methodology for the design and optimization of elastically actuated lower limb prostheses. In contrast to other studies, actuator inertia is considered in this paper. Further, the approach considers the inertial parameters of the prosthesis after initial design to revise the requirements and redesign the system. The design procedure is described and presented for the example of a powered prosthetic knee. In this, considering actuator inertia enables to find optimal stiffness values for walking that are not to be found with common methods and altered optimal values for other gait types. Further, the consideration of the inertial properties of the pre-designed prosthesis in a gait simulation lead to distinctly lower requirements for peak power. For walking those are decreased by about 10% while in running a reduction of over 30% is observed. Analyzing those results, the potential of considering actuator and prosthetic inertia in design and thus the benefits due to the presented method are pointed out.

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Conception and evaluation of a novel variable torsion stiffness for biomechanical applications

Cited by 20 publications

References 27 publications

Variable impedance actuators: A review

Variable impedance actuators: A review

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

Analyzing and considering inertial effects in powered lower limb prosthetic design

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