Zhang Collins Controller

Description

This controller applies a spline defined as a percent of gait. This requires a heel FSR.

The profile is based on: J. Zhang, P. Fiers, K.A. Witte, R.W. Jackson, K.L. Poggensee, C.G. Atkeson, & S.H. Collins (2017). Human-in-the-loop optimization of exoskeleton assistance during walking. in Science, vol. 356, no. 6344, pp. 1280-1284, doi: 10.1126/science.aal5054.

Parameters

Parameter index order can be found in ControllerData.h.

  • torque: Magnitude of the peak torque in Nm

  • peak_time: Time when the peak torque occurs (as a % of gait cycle)

  • rise_time: Time from zero torque until peak torque (expressed as a % of gait cycle)

  • fall_time: Time from peak torque until zero torque (expressed as a % of gait cycle)

  • direction: Flag that flips torque from PF to DF (essentailly an assistance/resistance flag)

  • use_pid: This flag turns PID on(1) or off(0)

  • p_gain: Proportional gain for closed-loop control.

  • i_gain: Integral gain for closed-loop control.

  • d_gain: Derivative gain for closed-loop control.