Rapid Manufacture of Novel Variable Impedance Robots

Enoch, Alexander; Vijayakumar, Sethu

doi:10.1115/1.4030388

Cited by 8 publications

(2 citation statements)

References 27 publications

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“…With an appropriate choice of the composite cost function to encode the task, we have demonstrated the effectiveness of the proposed approach in various example tasks in numerical simulations and hardware implementation in a brachiating robot with VSA. Future work will aim at investigation of optimization in biped locomotion with VSA including variable damping (Enoch and Vijayakumar 2016;Radulescu et al 2012) as well as an extension to learning approaches to address modelling uncertainties of the system dynamics (Mitrovic 2010).…”

Section: Resultsmentioning

confidence: 99%

Spatio-temporal stiffness optimization with switching dynamics

et al. 2016

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We address the optimal control problem of robotic systems with variable stiffness actuation (VSA) including switching dynamics and discontinuous state transitions. Our focus in this paper is to consider dynamic tasks that have multiple phases of movement, contacts and impacts with the environment with a requirement of exploiting passive dynamics of the system. By modelling such tasks as a hybrid dynamical system with time-based switching, we develop a systematic methodology to simultaneously optimize control commands, time-varying stiffness profiles and temporal aspect of the movement such as switching instances and total movement duration to exploit the benefits of VSA. Numerical evaluations on a brachiating robot driven with VSA Electronic supplementary material The online version of this article (

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Section: Resultsmentioning

confidence: 99%

Spatio-temporal stiffness optimization with switching dynamics

et al. 2016

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“…Previous research regarding the application of VSAs in humanoids showed modulation of walking velocity and step length in passive dynamic walkers (Huang et al, 2013), and the postural control of a biped (Hettich et al, 2011). Currently, only few examples of bipeds with VSAs can be found: Veronica (Huang et al, 2013), Lucy (Vanderborght et al, 2008), and BLUE/miniBLUE (Enoch and Vijayakumar, 2015). Several working principles for actuators with variable-stiffness capabilities have been proposed for various robotic applications.…”

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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