Multi-joint soft exosuit for gait assistance

Asbeck, Alan T.; Schmidt, Kai; Galiana, Ignacio; Wagner, Diana; Walsh, Conor J.

doi:10.1109/icra.2015.7140069

Cited by 93 publications

(64 citation statements)

References 24 publications

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“…Our laboratory has developed lightweight, soft wearable robots (exosuits) that interface with the paretic limb of individuals after stroke via garment-like, functional textile anchors (Bae et al, 2015). Exosuits produce gait-restorative joint torques by transmitting mechanical power generated by off-board (Bae et al, 2015;Ding et al, 2014;Quinlivan et al, 2017) or body-worn actuators (Asbeck et al, 2015;Panizzolo et al, 2016) to the paretic ankle through the interaction of the textile anchors with Bowden cables connected to the actuators. In previous work, we demonstrated that a laboratorybased exosuit testbed consisting of an off-board actuator and two textile modules that independently assisted paretic ankle PF and DF during walking (Awad et al, 2017a;Bae et al, 2015) (Fig.…”

Section: Introductionmentioning

confidence: 99%

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Bae

Awad

Long

et al. 2018

Journal of Experimental Biology

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Stroke-induced hemiparetic gait is characteristically asymmetric and metabolically expensive. Weakness and impaired control of the paretic ankle contribute to reduced forward propulsion and ground clearance - walking subtasks critical for safe and efficient locomotion. Targeted gait interventions that improve paretic ankle function after stroke are therefore warranted. We have developed textile-based, soft wearable robots that transmit mechanical power generated by off-board or body-worn actuators to the paretic ankle using Bowden cables (soft exosuits) and have demonstrated the exosuits can overcome deficits in paretic limb forward propulsion and ground clearance, ultimately reducing the metabolic cost of hemiparetic walking. This study elucidates the biomechanical mechanisms underlying exosuit-induced reductions in metabolic power. We evaluated the relationships between exosuit-induced changes in the body center of mass (COM) power generated by each limb, individual joint power and metabolic power. Compared with walking with an exosuit unpowered, exosuit assistance produced more symmetrical COM power generation during the critical period of the step-to-step transition (22.4±6.4% more symmetric). Changes in individual limb COM power were related to changes in paretic (=0.83, 0.004) and non-paretic (0.73, 0.014) ankle power. Interestingly, despite the exosuit providing direct assistance to only the paretic limb, changes in metabolic power were related to changes in non-paretic limb COM power (=0.80, 0.007), not paretic limb COM power (0.05). These findings contribute to a fundamental understanding of how individuals post-stroke interact with an exosuit to reduce the metabolic cost of hemiparetic walking.

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Section: Introductionmentioning

confidence: 99%

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Bae

Awad

Long

et al. 2018

Journal of Experimental Biology

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“…Our first efforts developing exosuits led to the creation of systems that could comfortably deliver assistive forces to healthy users during walking (39,40,(43)(44)(45)(46)(47). Recently, we demonstrated that assistive forces delivered through the exosuit interface produce marked reductions in the energy cost of healthy walking (37,48).…”

Section: Introductionmentioning

confidence: 99%

A soft robotic exosuit improves walking in patients after stroke

et al. 2017

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Stroke-induced hemiparetic gait is characteristically slow and metabolically expensive. Passive assistive devices such as ankle-foot orthoses are often prescribed to increase function and independence after stroke; however, walking remains highly impaired despite-and perhaps because of-their use. We sought to determine whether a soft wearable robot (exosuit) designed to supplement the paretic limb's residual ability to generate both forward propulsion and ground clearance could facilitate more normal walking after stroke. Exosuits transmit mechanical power generated by actuators to a wearer through the interaction of garment-like, functional textile anchors and cable-based transmissions. We evaluated the immediate effects of an exosuit actively assisting the paretic limb of individuals in the chronic phase of stroke recovery during treadmill and overground walking. Using controlled, treadmill-based biomechanical investigation, we demonstrate that exosuits can function in synchrony with a wearer's paretic limb to facilitate an immediate 5.33 ± 0.91°increase in the paretic ankle's swing phase dorsiflexion and 11 ± 3% increase in the paretic limb's generation of forward propulsion (P < 0.05). These improvements in paretic limb function contributed to a 20 ± 4% reduction in forward propulsion interlimb asymmetry and a 10 ± 3% reduction in the energy cost of walking, which is equivalent to a 32 ± 9% reduction in the metabolic burden associated with poststroke walking. Relatively low assistance (~12% of biological torques) delivered with a lightweight and nonrestrictive exosuit was sufficient to facilitate more normal walking in ambulatory individuals after stroke. Future work will focus on understanding how exosuit-induced improvements in walking performance may be leveraged to improve mobility after stroke.

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“…Consider the external disturbance during the control progress and denote ( ) = ( ) as the feedback output torque at the distal side of the CCMs, from Eq. (6), (9), and (10), one can write…”

Section: Controller Designmentioning

confidence: 99%

“…Flexible transmission mechanisms such as cable-conduit mechanism (CCM) and tendon-sheath mechanism (TSM) have been widely adopted and developed in many types of applications from surgical robots [1][2][3][4] to robotic hands [5,6], wearable robots [7], and soft exosuits [8,9]. A CCM (or a TSM) consists of a cable/tendon which goes through a flexible conduit/sheath and connects an actuator with the robotic joint.…”

Section: Introductionmentioning

confidence: 99%

Direct torque control for cable conduit mechanisms for the robotic foot for footwear testing

2018

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As the shoe durability is affected directly by the dynamic force/pressure between the shoe and its working environments (i.e., the contact ground and the human foot), a footwear testing system should replicate correctly this interaction force profile during gait cycles. Thus, in developing a robotic foot for footwear testing, it is important to power multiple foot joints and to control their output torque to produce correct dynamic effects on footwear. The cable conduit mechanism (CCM) offers great advantages for designing this robotic foot. It not only eliminates the cumbersome actuators and significant inertial effects from the fastmoving robotic foot but also allows a large amount of energy/force to be transmitted/propagated to the compact robotic foot. However, CCMs cause nonlinearities and hysteresis effects to the system performance. Recent studies on CCMs and hysteresis systems mostly addressed the position control. This paper introduces a new approach for modeling the torque transmission and controlling the output torque of a pair of CCMs, which are used to actuate the robotic foot for footwear testing. The proximal torque is used as the input signal for the Bouc-Wen hysteresis model to portray the torque transmission profile while a new robust adaptive control scheme is developed to online estimate and compensate for the nonlinearities and hysteresis effects. Both theoretical proof of stability and experimental validation of the new torque controller have been carried out and reported in this paper. Control experiments of other closed-loop control algorithms have been also conducted to compare their performance with the new controller effectiveness. Qualitative and quantitative results show that the new control approach significantly enhances the torque tracking performance for the system preceded by CCMs.

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Multi-joint soft exosuit for gait assistance

Cited by 93 publications

References 24 publications

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

A soft robotic exosuit improves walking in patients after stroke

Direct torque control for cable conduit mechanisms for the robotic foot for footwear testing

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