Series elastic actuator development for a biomimetic walking robot

Robinson, David; Pratt, Jerry; Paluska, Daniel; Pratt, Gill A.

doi:10.1109/aim.1999.803231

Cited by 347 publications

(227 citation statements)

References 12 publications

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“…The amount of tension in the rope is controlled using a custom-series elastic actuator [12][13][14][15]. As shown in Figure 2, two parallel plates slide along precision rails separated by two heavy-duty die springs.…”

Section: Unloading System Mechanicsmentioning

confidence: 99%

“…In this setting, as the patient moves up and down, they experience a constant amount of vertical support, which can be set as a percentage of the patient's body weight. Dynamic BWS has been shown to produce more natural ground-reaction forces and gait characteristics [11][12][13][14][15][16][17][18] and allows patients to move freely through a wide range of movement profiles (e.g., those needed during gait, sit-to-stand, and getting off the floor). Such activities are not possible with static BWS systems, yet are critical to a patient's ability to practice activities of daily living (ADLs).…”

Section: Introductionmentioning

confidence: 99%

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ZeroG: Overground gait and balance training system

Hidler¹,

Brennan²,

Black³

et al. 2011

JRRD

108

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Abstract-A new overground body-weight support system called ZeroG has been developed that allows patients with severe gait impairments to practice gait and balance activities in a safe, controlled manner. The unloading system is capable of providing up to 300 lb of static support and 150 lb of dynamic (or constant force) support using a custom-series elastic actuator. The unloading system is mounted to a driven trolley, which rides along an overhead rail. We evaluated the performance of ZeroG's unloading system, as well as the trolley tracking system, using benchtop and human-subject testing. Average root-mean-square and peak errors in unloading were 2.2 and 7.2 percent, respectively, over the range of forces tested while trolley tracking errors were less than 3 degrees, indicating the system was able to maintain its position above the subject. We believe training with ZeroG will allow patients to practice activities that are critical to achieving functional independence at home and in the community.

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Section: Unloading System Mechanicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

ZeroG: Overground gait and balance training system

Hidler¹,

Brennan²,

Black³

et al. 2011

JRRD

108

View full text Add to dashboard Cite

show abstract

“…The (electric) motors, which act in series, only excite the elastic oscillation and feed energy into the system. Conceptually, this is a major difference to classic series elastic actuators ( [8], [9], [10]), in which the spring deflection is regulated to create a well-defined output torque. A planar model of a one legged running robot was used to study different cost functions in gait optimization.…”

Section: Introductionmentioning

confidence: 99%

Comparison of cost functions for electrically driven running robots

Remy

Buffinton

Siegwart

2012

2012 IEEE International Conference on Robotics and Automation

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Abstract-In this work we apply optimal control to create running gaits for the model of an electrically driven one legged hopper, and compare the results obtained for five different objective functions. By using high compliant series elastic actuators, the motions of joint and motor are decoupled, which allows the exploitation of natural dynamics.Depending on the cost function, this exploitation varies. Energy is injected at different points of time, the amplitude of actuator action changes significantly, and the optimal gear ratios differ by a factor of two. Variations are, however, comparable over a wide range of hopping heights and running velocities. Purely force-based cost functions prove to be ill-suited for such non-conservative systems, and it is shown that thermal electrical losses, in contrast to common belief, do not dominate energy expenditure. The numerical results are corroborated by detailed analytical considerations which give general insights into optimal excitation with electric actuators.

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“…Biomechanical models of walking have shown that much of the leg's behavior during gait can be accomplished using passive energy storage elements at the various joints [4]. Series elastic actuators have been used in several walking robots over the years as they provide more lifelike motions, have inherent impact tolerance, and ease control requirements [5][6]. While walking over level ground, energy is largely conserved via storage, transfer, and timed discharge of potential energy with minimal propulsive input needed from the hip.…”

Section: Introductionmentioning

confidence: 99%

Metabolic effects of using a variable impedance prosthetic knee

2016

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Abstract-A transfemoral amputation has a significant effect on walking. Though current prosthetic knee options serve to restore mobility, as purely passive devices, they do not fully restore nondisabled gait. Persons with transfemoral amputation incur a higher metabolic cost during walking than persons without amputation and as a result walk slower and for shorter distances before tiring. An original variable-impedance transmission prosthetic knee (VI Knee) was tested in five study participants with unilateral transfemoral amputation at two steadystate walking speeds, one below and one above their preferred walking speed. While walking with the VI Knee, participants with shorter limbs showed a reduction in metabolic cost compared with their conventional C-Leg prosthesis, while those with longer limbs exhibited an increase. Though differences were observed between speeds, overall the difference in metabolic cost (reduction or increase) was found to correlate significantly with rise in the center of mass, with those with shorter residual limbs exhibiting less overall lifting of the body during gait.

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Series elastic actuator development for a biomimetic walking robot

Cited by 347 publications

References 12 publications

ZeroG: Overground gait and balance training system

ZeroG: Overground gait and balance training system

Comparison of cost functions for electrically driven running robots

Metabolic effects of using a variable impedance prosthetic knee

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