Controlling power in a prosthesis or orthosis based on predicted walking speed or surrogate for same

An ankle-foot prosthesis or orthosis apparatus comprising:

• a shank member;
• a foot member that is operatively configured with respect to the shank member so as to support walking and permit the foot member to plantarflex and dorsiflex with respect to the shank member;
• a motor configured to plantarflex the foot member with respect to the shank member;
• a series elastic element connected between at least one of (a) the motor and the shank member and (b) the motor and the foot member;
• a first sensor having an output serving as a surrogate for walking speed;
• and
• a controller configured to:
• determine, based on the output of the first sensor, a control value corresponding to at least one of:
• an angular rate ωx of the shank member at a start of controlled dorsiflexion, an angular rate of a leg section above a knee of a user of the apparatus, a knee linear moving velocity in a stance phase, or a Cartesian trajectory of an ankle joint of the apparatus or the knee, and
• control the motor's torque, based on the determined control value, so that the motor's torque for slow walking speeds is lower than the motor's torque for fast walking speeds.