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Figure 2 | Journal of NeuroEngineering and Rehabilitation

Figure 2

From: The influence of push-off timing in a robotic ankle-foot prosthesis on the energetics and mechanics of walking

Figure 2

Prosthesis torque components in timing conditions. (A) Spring-like torque component, shown in torque-angle space, programmed as a function of prosthesis joint angle (cf. zero-work condition [18]). Solid line is dorsiflexion phase, dashed line is plantarflexion phase. (B) Time-torque component, shown in time, programmed as a square wave that started at the desired percent of predicted stride period and lasted 10% of stride period or until toe off. Actual, measured torque increased and decreased gradually. Lines representing earlier torque bursts appear longer than 10% due to averaging of bursts with temporal variation. Bars of later bins are shorter than 10% because the prosthesis leaves the ground. Curve colors correspond to Time-torque onsets. Horizontal bars indicate Time-torque period, and error bars are standard deviation. Vertical dashed lines indicate mean timing of intact-side heel contact and prosthesis toe off. (C) Total torque, shown in torque-angle space, was the sum of the Spring-like torque and Time-torque components. Enclosed area is net prosthesis work, which was maintained across timing conditions. Colors are Time-torque bins. All lines and bars represent population means.

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