Adaptation in Variable Parallel Compliance: Towards Energy Efficiency in Cyclic Tasks

Nasiri, Rezvan; Khoramshahi, Mahdi; Shushtari, Mohammad; Ahmadabadi, Majid Nili

doi:10.1109/tmech.2016.2637826

Cited by 29 publications

(30 citation statements)

References 37 publications

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“…That is: (12) where n = n(θ 0 ) from the rolling contact constraints (Equations (6) and 7). Therefore, using this relationship and Equations (10) and (11), a single nonlinear equation in θ 0 is obtained, which can be solved using a tool such as Matlab's fsolve or a custom line search. Additionally, parameters a and b can be found by this process.…”

Section: Numerical Solution Methodsmentioning

confidence: 99%

“…The following abbreviations are used in this manuscript: End deflections a and b presented in Equations (10) and (11) of Section 3.2 are defined by using a set of homogeneous coordinate transformations (translation and rotation), which is presented in the following:…”

Section: Conflicts Of Interestmentioning

confidence: 99%

“…SEA design may be optimized with the goal of decreasing energy consumption by proper selection of the compliant element's stiffness [9]. Furthermore, optimization techniques may be used to select the motor and the mechanism parameters [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Design and Analysis of Novel Actuation Mechanism with Controllable Stiffness

Santos

Richter

2019

Actuators

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Actuators intended for human–machine interaction systems are usually designed to be mechanically compliant. Conventional actuators are not suitable for this purpose due to typically high stiffness. Advanced powered prosthetic and orthotic devices can vary their stiffness during a motion cycle and are power-efficient. This paper proposes a novel actuator design that modulates stiffness by means of a flexible beam. A motorized drive system varies the active length of the cantilever beam, thus achieving stiffness modulation. New large deflection formulation for cantilever beams with rolling contact constraints is used to determine the moment produced by the actuator. To validate the proposed solution method, an experiment was performed to measure large static deformations of a cantilever beam with the same boundary conditions as in the actuator design. The experiments indicate excellent agreement between measured and calculated contact forces between beam and roller, from which the actuator moment is determined.

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Section: Numerical Solution Methodsmentioning

confidence: 99%

Section: Conflicts Of Interestmentioning

confidence: 99%

See 1 more Smart Citation

Design and Analysis of Novel Actuation Mechanism with Controllable Stiffness

Santos

Richter

2019

Actuators

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show abstract

“…The research in this field mainly addresses the development of mechanisms to realize variable stiffness springs [57][58][59] and non-linear off-the-shelf springs [60][61][62][63]. Indeed, non-linear stiffness allows a larger energy saving in robots, since actuators torques and end-effector trajectory are always related by non-linear behavior, as demonstrated in References [58,64,65].…”

Section: Parallel Compliance Elementsmentioning

confidence: 99%

Natural Motion for Energy Saving in Robotic and Mechatronic Systems

et al. 2019

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Energy saving in robotic and mechatronic systems is becoming an evermore important topic in both industry and academia. One strategy to reduce the energy consumption, especially for cyclic tasks, is exploiting natural motion. We define natural motion as the system response caused by the conversion of potential elastic energy into kinetic energy. This motion can be both a forced response assisted by a motor or a free response. The application of the natural motion concepts allows for energy saving in tasks characterized by repetitive or cyclic motion. This review paper proposes a classification of several approaches to natural motion, starting from the compliant elements and the actuators needed for its implementation. Then several approaches to natural motion are discussed based on the trajectory followed by the system, providing useful information to the researchers dealing with natural motion.

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“…Accordingly, it is inferred that each optimum cyclic motion have a compatible compliance element. Consequently, an inverse problem comes to mind where in our previous works [47,48], we provided methods to find the optimal compliance for a given periodic motion.…”

Section: Periodic Motions Need Compliancementioning

confidence: 99%

Adaptive Natural Oscillator to exploit natural dynamics for energy efficiency

Khoramshahi

Nasiri

Shushtari

et al. 2017

Robotics and Autonomous Systems

Self Cite

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We present a novel adaptive oscillator, called Adaptive Natural Oscillator (ANO), to exploit the natural dynamics of a given robotic system. This tool is built upon the Adaptive Frequency Oscillator (AFO), and it can be used as a pattern generator in robotic applications such as locomotion systems. In contrast to AFO, that adapts to the frequency of an external signal, ANO adapts the frequency of reference trajectory to the natural dynamics of the given system. In this work, we prove that, in linear systems, ANO converges to the system's natural frequency. Furthermore, we show that this tool exploits the natural dynamics for energy efficiency through minimization of actuator effort. This property makes ANO an appealing tool for energy consumption reduction in cyclic tasks; especially in legged systems. We also extend the proposed adaptation mechanism to high dimensional and general cases; such as n-DOF manipulators. In addition, by investigating a hopper leg in simulation, we show the efficacy of ANO in face of dynamical discontinuities; such as those inherent in legged locomotion. Furthermore, we apply ANO to a simulated compliant robotic manipulator performing a periodic task where the energy consumption is drastically reduced. Finally, the experimental results on a 1-DOF compliant joint show that our adaptive oscillator, despite all practical uncertainties and deviations from theoretical models, exploits the natural dynamics and reduces the energy consumption.

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Adaptation in Variable Parallel Compliance: Towards Energy Efficiency in Cyclic Tasks

Cited by 29 publications

References 37 publications

Design and Analysis of Novel Actuation Mechanism with Controllable Stiffness

Design and Analysis of Novel Actuation Mechanism with Controllable Stiffness

Natural Motion for Energy Saving in Robotic and Mechatronic Systems

Adaptive Natural Oscillator to exploit natural dynamics for energy efficiency

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