Terrain adaptive powered joint orthosis

A method for assisting a person walking on a surface with a powered human augmentation device including a controller and a joint capable of exhibiting a torque and an impedance, the method comprising the steps of:

• determining that a phase of a gait cycle is an early stance or mid-stance phase;
• estimating within the gait cycle, that a slope of the surface is a flat slope;
• estimating a walking speed of the person walking on the surface;
• supplying to the joint at least one of an augmentation torque or a value for the impedance, the impedance comprising a linear spring component and a damping component;
• and
• modulating the impedance based on the phase of the gait cycle and the walking speed to provide at least a biomimetic response, wherein the modulating comprises:
• sending a control signal to the powered actuator based on a determination that the phase of the gait cycle is one of early stance or mid stance and a determination that the estimated slope of the surface is substantially zero, the control signal to cause the powered actuator to provide the modulated impedance while the person is in the early stance or mid-stance phase of the gait cycle such that contribution of the linear spring component of the modulated impedance is greater than contribution of the damping component of the modulated impedance.