Powered orthotic system for cooperative overground rehabilitation

A method of performing overground rehabilitation for a wearer of a powered orthotic system comprising:

• initially establishing the powered orthotic system to perform gait functions for the wearer based on a predetermined level of assistance;
• and
• adaptively varying the predetermined level of assistance based on a rehabilitation parameter of the wearer, wherein:
• (1) varying the predetermined level of assistance includes establishing a virtual back wall, and establishing the virtual back wall includes (a) computing a trailing back wall which follows behind a trajectory of a path of the wearer, (b) allowing said trailing back wall to advance along said path even if when the wearer reduces or even ceases progress along said path, (c) identifying a condition when a position of said back wall is identical to a position of said wearer and (d) modifying an assistive force applied to said wearer to force continued motion along said path;
• or
• (2) varying the predetermined level of assistance includes coordinating torques between legs of the wearer, and coordinating the torques includes (a) identifying a condition of imbalance between hip joints of the powered orthotic system that results in adverse motion of a torso of the powered orthotic system, and (b) adjusting torsions in the hip joints to balances forces.

An overground rehabilitative powered orthotic system including an exoskeleton comprising:

• a torso portion configurable to be coupled to an upper body of a person;
• at least one leg support configurable to be coupled to a first lower limb of the person, with the at least one leg support including at least a thigh link rotatably connectable to the torso portion at a hip joint, and a shank link rotatably connectable to the thigh link at a knee joint;
• a first actuator for controlling motion of said hip joint;
• a second actuator for controlling motion of said knee joint;
• a plurality of sensors for monitoring the exoskeleton;
• and
• a controller configured to control the first and second actuators with adaptive, variable levels of assistance in response to signals from the plurality of sensors by initially establishing the exoskeleton to perform gait functions for the person based on a predetermined level of assistance and adaptively varying the predetermined level of assistance based on a rehabilitation parameter of the person, wherein:
• (1) the controller is configured to (a) define a desired assistance trajectory, (b) define one or more segments along said desired assistance trajectory, and (c) assign to each of said one or more segments a function proportional to a distance from said desired assistance trajectory;
• or
• (2) the controller is configured to (a) determine a previous position along a trajectory, (b) determine a current position along said trajectory, (c) determine a rate of progress along said trajectory, and (d) estimate, from said previous position, said current position and said rate, a future trajectory.