Franks Collins Hip Controller

Description

Provides Hip assistance based on a series of splines that have an extension and flexion portion. Uses percent gait, requiring heel FSR.

Based on:

P.W. Franks, G.M. Bryan, R.M. Martin, R. Reyes, A.C. Lakmazaheri, & S.H. Collins (2021). Comparing optimized exoskeleton assistance of the hip, knee, and ankle in single and multi-joint configurations. in Wearable Technologies, vol. 2, pp. e16, doi: 10.1017/wtc.2021.14.

Parameters

Parameter index order can be found in ControllerData.h.

  • mass: User mass in kg used for denormalizing torque, currently not used in the controller but easy to implement if desired, defaults to zero as a result.

  • trough_normalized_torque_Nm_kg: Largest extension torque (Nm). Note: Currently not noramlized by user mass.

  • peak_normalized_torque_Nm_kg: Largest flexion torque (Nm). Note: Currently not noramlized by user mass.

  • start_percent_gait: Percent gait to start the torque pattern so it doesn’t have a discontinuity at heel strike.

  • trough_onset_percent_gait: Percent gait to start applying extension torque.

  • trough_percent_gait: Percent gait to apply the largest extension torque.

  • mid_time: Transition point between extension and flexion to apply 0 torque.

  • mid_duration: The duration of the transition pause as a percent of the gait cycle.

  • peak_percent_gait: Percent gait to apply the largest flexion torque.

  • peak_offset_percent_gait: Percent gait to stop applying flexion torque.

  • 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