Elastic Element Exoskeleton and Method of Using Same

Abstract

Running in a mammal, such as a human, is augmented by adaptively modulating anticipation of maximum leg extension of a mammal when running, and actuating an exoskeletal clutch linked in series to at least one elastic element, wherein the clutch and elastic element form an exoskeleton and are attached in parallel to at least one muscle-tendon unit of a leg of the mammal and span at least one joint of the mammal fitted with the exoskeleton. The exoskeletal clutch is actuated in advance of a predicted maximum extension of the exoskeletal clutch to thereby cause the exoskeletal clutch to lock essentially simultaneously with ground strike by the leg of the mammal. The elastic element is thereby engaged during stance phase of the gait of the mammal while running, and subsequently is disengaged prior to or during the swing phase of the gait of the mammal, thereby augmenting running of the mammal.

What is claimed is: 
     
         1 . A method for augmenting running in a mammal, comprising the steps of:
 a) adaptively modulating anticipation of a maximum extension of an exoskeletal clutch linked to at least one elastic element, the exoskeletal clutch and the elastic element being an exoskeleton attached in parallel to at least one muscle-tendon unit of a leg of the mammal and spanning at least one joint of the mammal, to thereby estimate a predicted maximum extension of the exoskeletal clutch prior to leg strike of the mammal while running;   b) actuating the exoskeletal clutch in advance of the predicted maximum extension of the exoskeletal clutch, to thereby cause the exoskeletal clutch to lock essentially simultaneously with the ground strike of the leg by the mammal, whereby the elastic element is engaged during a stance phase of the gait of the mammal while running; and   c) disengaging the elastic element prior to or during a swing phase of the gait of the mammal, thereby augmenting running in the mammal.   
     
     
         2 . The method of  claim 1 , wherein adaptively modulating anticipation of the maximum extension of the exoskeletal clutch includes correlating both
 a) a position of the exoskeletal clutch; and   b) an angular velocity of the exoskeleton in a sagittal plane of the mammal, with a phase of the gait cycle of the mammal while running, to thereby estimate the predicted maximum extension of the exoskeletal clutch prior to leg strike of the mammal while running.   
     
     
         3 . The method of  claim 2 , wherein adaptively modulating anticipation of the maximum extension of the exoskeletal clutch further includes, upon or after estimating the predicted the maximum extension, correlating past positions of the exoskeletal clutch during terminal swing phase with each other, to thereby predict maximum extension of the exoskeletal clutch while running. 
     
     
         4 . The method of  claim 3 , wherein the elastic element is disengaged by:
 a) correlating the position of the exoskeletal clutch and the angular velocity of the exoskeleton with a mid-stance phase of the gait cycle; and   b) actuating disengagement of the exoskeletal clutch during the mid-stance phase.   
     
     
         5 . The method of  claim 3 , wherein correlating the past positions of the exoskeletal clutch to predict maximum extension of the exoskeleton includes using a latency compensation algorithm. 
     
     
         6 . The method of  claim 5 , wherein the latency compensation algorithm includes a quadratic least squares analysis. 
     
     
         7 . The method of  claim 5 , wherein the latency compensation algorithm includes fitting differentials of encoder readings to a line and seeking a zero crossing. 
     
     
         8 . The method of  claim 1 , wherein the clutch is a rotary clutch. 
     
     
         9 . The method of  claim 8 , wherein the elastic element includes a leaf spring. 
     
     
         10 . The method of  claim 9 , wherein the rotary clutch links two leaf springs in series. 
     
     
         11 . The method of  claim 1 , wherein the exoskeleton spans a knee joint of the mammal. 
     
     
         12 . The method of  claim 11 , wherein the exoskeleton further spans an ankle joint of the mammal. 
     
     
         13 . The method of  claim 12 , wherein the exoskeleton further spans a hip joint of the mammal. 
     
     
         14 . The method of  claim 11 , wherein the exoskeleton further spans at least one of an ankle joint and a hip joint of the mammal. 
     
     
         15 . The method of  claim 1 , wherein the clutch is a linear clutch. 
     
     
         16 . The method of  claim 15 , wherein the elastic element is at least one member selected from the group consisting of a leaf spring, compression spring and tension spring. 
     
     
         17 . A method for augmenting running in a mammal, comprising the steps of:
 a) adaptively anticipating a maximum extension of an exoskeletal clutch, to thereby estimate a predicted maximum extension of the exoskeletal clutch prior to leg strike of the mammal while running;   b) actuating the exoskeletal clutch in advance of the predicted maximum extension of the exoskeletal clutch; and   c) disengaging the exoskeletal clutch prior to or during a swing phase of the gait of the mammal, thereby augmenting running in the mammal.