Series elastic actuators

Pratt, Gill A.; Williamson, Matthew M.

doi:10.1109/iros.1995.525827

Cited by 1,684 publications

(968 citation statements)

References 34 publications

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“…Because of the important uses of compliance in locomotion [69], the concept of series elastic actuators mimicking muscles has been introduced [70] and applied in the last decades [71] in robotics. What might have seemed to be a simplistic approach, namely to represent muscle behaviour by means of motors in series with springs, may actually represent observed muscle behaviour during stretch very well.…”

Section: Discussionmentioning

confidence: 99%

The active force–length relationship is invisible during extensive eccentric contractions in skinned skeletal muscle fibres

et al. 2017

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In contrast to experimentally observed progressive forces in eccentric contractions, cross-bridge and sliding-filament theories of muscle contraction predict that varying myofilament overlap will lead to increases and decreases in active force during eccentric contractions. Non-cross-bridge contributions potentially explain the progressive total forces. However, it is not clear whether underlying abrupt changes in the slope of the nonlinear forcelength relationship are visible in long isokinetic stretches, and in which proportion cross-bridges and non-cross-bridges contribute to muscle force. Here, we show that maximally activated single skinned rat muscle fibres behave (almost across the entire working range) like linear springs. The force slope is about three times the maximum isometric force per optimal length. Cross-bridge and non-cross-bridge contributions to the muscle force were investigated using an actomyosin inhibitor. The experiments revealed a nonlinear progressive contribution of non-cross-bridge forces and suggest a nonlinear cross-bridge contribution similar to the active force-length relationship (though with increased optimal length and maximum isometric force). The linear muscle behaviour might significantly reduce the control effort. Moreover, the observed slight increase in slope with initial length is in accordance with current models attributing the non-cross-bridge force to titin.

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Section: Discussionmentioning

confidence: 99%

The active force–length relationship is invisible during extensive eccentric contractions in skinned skeletal muscle fibres

et al. 2017

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“…A modular muscle unit, based on the principle of series elastic actuator [10], has been developed for the muscles of the Anthrob robot. The muscle unit comprises a brushed Direct Current (DC) motor, equipped with a gear, optional pulleys for tendon routing, sensors for muscle control (see below) and a spindle which is supported by a sliding bearing to reduce radial forces on the transmission shaft.…”

Section: B Musclesmentioning

confidence: 99%

Anthrob - A printed anthropomimetic robot

Jantsch

Wittmeier²,

Dalamagkidis³

et al. 2013

2013 13th IEEE-RAS International Conference on Humanoid Robots (Humanoids)

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Abstract-Anthropomimetic robotics differ from conventional approaches by capitalizing on the replication of the inner structures of the human body, such as muscles, tendons, bones and joints [1]. Prominent examples for this class of robots are the robots developed at the JSK laboratory of the University of Tokyo and the robots developed by the EU-funded project Embodied Cognition in a Compliantly Engineered Robot (Eccerobot). However, the high complexity of these robots as well as their lack of sensors has so far failed to provide the desired new insights in the field of control.Therefore, we developed the simplified but sensorized robot Anthrob. The robot replicates the human upper limb and features 13 compliant tendon driven uni-and biarticular muscles as well as a spherical shoulder joint. Whenever possible, Selective Laser Sintering (SLS) was used for the production of the robot parts to reduce the production costs and to implement cutting-edge technologies, such as tendon canals or solid-state joints.

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“…One of the first realizations of a compliant actuator was the MIT Series Elastic Actuator [3], which has an inherent, but fixed compliance. For shock absorbance this is useful, but in order to use natural dynamics this approach is limited to one eigenfrequency since the spring constant is fixed.…”

Section: Stemmentioning

confidence: 99%

MACCEPA: the Actuator with Adaptable Compliance for Dynamic Walking Bipeds

Ham

Vanderborght

Damme

et al. 2006

Climbing and Walking Robots

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Walking robots can be divided into two categories: on one hand the fully actuated robots that don't use passive dynamics, and on the other hand the energy efficient passive walkers. For autonomous robots the energy storage is a problem, forecasting a bright future for passive walkers. At this moment the passive walkers are restricted to one walking speed due to the eigenfrequency, which is fixed by the mechanical constructions. Several actuators with adaptable compliant have been designed, but due to size, complexity or controllability these are difficult to implement in mpliance ca for dynamic walking, human-robotic interfaces and robotic rehabilitation devices. mpliance, Equilibrium Position, Actuators, Compliance control, Spring bipeds. Another application of the use of adaptable compliance is safe robothuman interaction. Sometimes a robot has to be stiff, e.g. for pick and place operations, but when moving between humans, a robot is preferably compliant. Also for exoskeletons or rehabilitation devices this co n improve ergonomics and speed up the rehabilitation process. The MACCEPA is a straightforward and easy to construct rotational actuator, of which the compliance can be controlled separately from the equilibrium position. The generated torque is a linear function of the compliance and of the angle between equilibrium position and actual position. This makes this actuator perfectly suitable

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Series elastic actuators

Cited by 1,684 publications

References 34 publications

The active force–length relationship is invisible during extensive eccentric contractions in skinned skeletal muscle fibres

The active force–length relationship is invisible during extensive eccentric contractions in skinned skeletal muscle fibres

Anthrob - A printed anthropomimetic robot

MACCEPA: the Actuator with Adaptable Compliance for Dynamic Walking Bipeds

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