Series Clutch Actuators for safe physical human-robot interaction

Lauzier, Nicolas; Gosselin, Clément

doi:10.1109/icra.2011.5979601

Cited by 44 publications

(19 citation statements)

References 11 publications

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“…To resolve these limitations, a mechanism to engage or vary the stiffness is necessary. Although clutch mechanisms [20], [21] or variable compliance mechanisms [8], [9], [11], [12], [13], [14], [15] in series to the actuator in the drive train are well established, low cost, low-complexity solutions of clutched parallel elastic actuators (CPEA) have so far not been established. We presented a prototype for such a CPEA and a simple trigger-based control of it for rebounding tasks in legged locomotion.…”

Section: Discussion and Future Plansmentioning

confidence: 99%

A clutched parallel elastic actuator concept: Towards energy efficient powered legs in prosthetics and robotics

Haeufle

Taylor

Schmitt

et al. 2012

2012 4th IEEE RAS &Amp; EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob)

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Parallel passive-elastic elements can reduce the energy consumption and torque requirements for motors in powered legged systems. However, the hardware design for such combined actuators is challenged by the need to engage and disengage the parallel elasticity depending on the gait phase. Although clutches in the drive train are often proposed, compact and low cost solutions of clutched parallel elastic actuators have so far not been established. Here we present the design and control of an initial prototype for a parallel elastic actuator. The actuator combines a DC motor with a parallel spring that is engaged and disengaged by a commercially available, compact and low-cost electric clutch. In experiments that mimic the torque and motion patterns of knee extensor muscles in human rebounding tasks we find that the parallel spring in the prototype reduces the energy consumption of the actuator by about 80% and the peak torque requirement for the DC motor by about 66%. In addition, we find that a simple trigger-based control can reliably engage and disengage the electric clutch during the motion, allowing the spring to support the motor in rebound, to remove stored energy from the system as necessary for stopping, and to virtually disappear at the actuator output level. On the other hand, the hardware experiments also reveal that our initial design limits the precision in the torque control, and we propose specific improvements to overcome these limitations.

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Section: Discussion and Future Plansmentioning

confidence: 99%

A clutched parallel elastic actuator concept: Towards energy efficient powered legs in prosthetics and robotics

Haeufle

Taylor

Schmitt

et al. 2012

2012 4th IEEE RAS &Amp; EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob)

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“…in miniaturized applications [18]). Third, the conic profile allows a torque transmission given both by normal contact forces and friction components, while disk clutches [19] completely rely on the latter. As additional feature, the clutch has an intermediate position (Fig.…”

Section: Discussionmentioning

confidence: 99%

A clutch mechanism for switching between position and stiffness control of a variable stiffness actuator

Cempini

Fumagalli

Vitiello

2015

2015 IEEE International Conference on Robotics and Automation (ICRA)

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Variable stiffness actuators (VSA) are fostered in robotics for their capability to address physical interaction with a physically adjustable compliance, being advantageous in terms of efficiency, safety and adaptability to unknown environments. Here we introduce the concept of a switching VSA (sVSA), in which a single actuator is used to control the position or the stiffness of a robotic joint according to a mechanical switch. Despite not allowing simultaneous control of both quantities, this architecture has the potential to make the design lighter, requiring one continuously powered actuator, controllable in position, and one additional switch, activated only occasionally between two limit stages: the advantages are the separation of the motors power requirements and a simpler control. A first prototype of a 1-DoF revolute variable-stiffness joint has been built, based on the vsaUT-II developed at the University of Twente, with a novel clutch mechanism allowing continuous and efficient switching. The prototype proved functionality and feasibility of the sVSA concept

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“…An alternative is constituted by friction dampers, in which the contact between moving components produces frictional forces. Damping can be modulated, for example, modifying the contact of two surfaces through piezoelectric actuators as proposed in the VPDA (Variable Physical Damping Actuator, [62]) or compressing a stack of discs as for the WDB (Wafer Disc Brake, [68]) and for the SCA (Series Clutch Actuator, [69]). These systems are clean, lightweight and they can be more easily embedded in compliant joints but they vary their mechanical properties in time due to the wear of the contacting surfaces.…”

Section: Physically Controllable Dampersmentioning

confidence: 99%

Double actuation architectures for rendering variable impedance in compliant robots: A review

et al. 2012

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Series Clutch Actuators for safe physical human-robot interaction

Cited by 44 publications

References 11 publications

A clutched parallel elastic actuator concept: Towards energy efficient powered legs in prosthetics and robotics

A clutched parallel elastic actuator concept: Towards energy efficient powered legs in prosthetics and robotics

A clutch mechanism for switching between position and stiffness control of a variable stiffness actuator

Double actuation architectures for rendering variable impedance in compliant robots: A review

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