Powered gait assistance systems

Abstract

Disclosed are powered gait assistance systems that include a controller, sensors, and a torque applicator (motor, spring, etc.) coupled to a patient's hips, thighs, knee, lower leg, ankle, and/or foot and operable to apply assistive torque to the patient's leg joint(s) to assist the patient's volitional joint actuating muscle output during selected stages of the patient's gait cycle, such that the applied torque improves the patient's leg posture, muscle output, range of motion, and/or other parameters over the gait cycle. The sensors can include a torque sensor that measures torque applied, one or more joint angle sensors, a ground contact sensor that measures ground contact of the patient's foot, and/or other sensors. The controller can determine what stage of the patient's gait cycle the patient's leg is in based on sensor signals and cause the torque applicator to apply corresponding torque to the joint(s) based on the gait cycle stage, sensor inputs, and known patient characteristics.

1 . A powered gait assistance system, comprising:
 a first arm and a second arm coupled together to allow relative pivoting between the first and second arms, wherein the first arm is configured to be coupled to an upper leg portion of a patient and the second arm is configured to be coupled to a lower leg portion of the patient such that relative pivoting between the first and second arms is about an axis proximate the patient's native knee pivot axis;   a torque applicator coupled to the first and second arms and operable to apply torque between the first and second arms;   an angle sensor that measures a relative angular position between the first and second arms;   a foot sensor that measures contact of the patient's foot with a ground surface;   at least one muscle output sensor configured to measure a volitional knee pivoting muscle output; and   a controller programmed to:
 determine a stage of a gait cycle a leg of the patient is in based on signals from one or more of the foot sensor and the angle sensor; 
 determine a volitional knee pivoting muscle output via one or more muscle output sensors over the course of the gait cycle; and 
 based on the determined stage of the patient's gait cycle, cause the torque applicator to apply a level of torque between the first and second arms to assist or resist the volitional knee pivoting muscle output during selected stages of the gait cycle, such that the torque applied by the torque applicator changes the patient's leg posture over the gait cycle, wherein the level of torque applied between the first and second arms is based on the volitional knee pivoting muscle output. 
   
     
     
         2 . The system of  claim 1 , wherein the change to the patient's leg posture comprises an improvement that causes the patient to walk in a more energy efficient manner. 
     
     
         3 . The system of  claim 1 , wherein the torque applied by the torque applicator at selected stages of the gait cycle trains the patient's muscles to control the patient's joints while walking. 
     
     
         4 . The system of  claim 1 , wherein the system is configured to increase the volitional knee pivoting muscle output over time. 
     
     
         5 . The system of  claim 1 , wherein the torque applied by the torque applicator at selected stages of the gait cycle increases the patient's knee range of motion and reduces crouch during the gait cycle. 
     
     
         6 . The system of  claim 1 , wherein the system allows the patient to produce greater volitional knee pivoting muscle output at the knee joint. 
     
     
         7 . The system of  claim 1 , wherein the torque applicator comprises a motor, and the system further comprising a chain or cable transmission system that transfers power from the motor to the first and second arms. 
     
     
         8 . The system of  claim 1 , wherein the system is modular and can be attached to or include a traditional knee-ankle-foot orthotic. 
     
     
         9 . The system of  claim 1 , wherein the system resists patient knee joint extension by applying a flexor torque during a late swing phase of the gait cycle prior to foot touch down. 
     
     
         10 . The system of  claim 9 , wherein the system assists patient knee joint extension during a ground contact phase of the gait cycle prior to toe take off. 
     
     
         11 .- 13 . (canceled) 
     
     
         14 . The system of  claim 1 , wherein the torque applicator is positioned:
 anterior to the patient's knee;   lateral to the patient's thigh; or   on the patient's torso or hips.   
     
     
         15 .- 16 . (canceled) 
     
     
         17 . The system of  claim 1 , further comprising a transmission system that increases torque output of the torque applicator. 
     
     
         18 .- 19 . (canceled) 
     
     
         20 . A method of controlling a powered gait assistance device, comprising:
 determining a stage of a gait cycle a leg of a patient utilizing the powered gait assistance device is in based on signals from a ground contact sensor and a knee angle sensor of the powered gait assistance device;   determining a volitional knee pivoting muscle output via one or more muscle output sensors over the course of the gait cycle; and   based on the determined stage of the gait cycle, causing the powered gait assistance device to apply a level of torque to a knee joint of the patient to assist or resist the volitional knee pivoting muscle output during selected stages of the gait cycle, such that the torque applied changes the patient's leg posture over the gait cycle, wherein the level of torque applied to the knee joint is based on the volitional knee pivoting muscle output.   
     
     
         21 . The method of  claim 20 , wherein the level of torque causes the volitional knee pivoting muscle output to increase over time. 
     
     
         22 . The method of  claim 20 , wherein causing the powered gait assistance device to apply the level of torque to the knee joint comprises resisting patient knee joint extension by applying a flexor torque during a late swing phase of the gait cycle, prior to foot touch down. 
     
     
         23 . The method of  claim 20 , wherein causing the powered gait assistance device to apply torque to the knee joint comprises assisting patient knee joint extension during a ground contact phase of the gait cycle, prior to toe take off. 
     
     
         24 . The method of  claim 23 , wherein causing the powered gait assistance device to apply the level of torque to the knee joint comprises providing no assistive or resistive torque to the patient knee joint during an early swing phase of the gait cycle, after toe take off. 
     
     
         25 .- 26 . (canceled) 
     
     
         27 . The system of  claim 1 , wherein the level of torque between the first and second arms during at least one stage of the gait cycle assists the volitional knee pivoting muscle output, and the level of torque applied to the knee joint during at least one other stage of the gait cycle resists the volitional knee pivoting muscle output. 
     
     
         28 . The method of  claim 20 , wherein the level of torque applied to the knee joint during at least one stage of the gait cycle assists the volitional knee pivoting muscle output, and the level of torque applied to the knee joint during at least one other stage of the gait cycle resists the volitional knee pivoting muscle output.