Figure 2
Error weighting function. We designed a weighting function, β(ei), which scales the feedback error contribution to the robotic assistance force. If the step height error falls within the 2δ (6σ) window then the robot assistance decays as a function of equation 18. The transition zone defined by W = 1/2 σ in equation 18, allowed a smooth transition from 0 to 1 using a weighted hyperbolic tangent function.