Virtually-interfaced robotic ankle & balance trainer

Abstract

According to an aspect of the invention, a robotic ankle and balance training platform comprises a footplate to support a foot. The footplate is capable of rotation about an inversion/eversion axis and a plantar/dorsiflexion axis. The robotic platform further comprises an actuation system configured to apply an assistive inversion/eversion force and a resistive inversion/eversion force to the footplate and an assistive plantar/dorsiflexion force and a resistive plantar/dorsiflexion force to the footplate.

1 . A robotic ankle and balance training platform comprising:
 a footplate to support a foot, said footplate capable of rotation about an inversion/eversion axis and a plantar/dorsiflexion axis; and   an actuation system configured to apply:
 an assistive inversion/eversion force and a resistive inversion/eversion force to the footplate; and 
 an assistive plantar/dorsiflexion force and a resistive plantar/dorsiflexion force to the footplate. 
   
     
     
         2 . The robotic ankle and balance training platform of  claim 1 , further comprising:
 an inversion/eversion frame to allow rotation of the footplate about the inversion/eversion axis; and   a plantar/dorsiflexion frame to allow rotation of the footplate about the plantar/dorsiflexion axis.   
     
     
         3 . The robotic ankle and balance training platform of  claim 2 , wherein one of the inversion/eversion frame and the plantar/dorsiflexion frame are integral with the footplate. 
     
     
         4 . The robotic ankle and balance training platform of  claim 1 , further comprising:
 sensors for measuring at least one of tensile force, compressive force, and footplate position.   
     
     
         5 . The robotic ankle and balance training platform of  claim 4 , wherein sensors comprise:
 at least one pair of load cells; and   at least one spring configured to assert a preload on the at least one load cell pair.   
     
     
         6 . The robotic ankle and balance training platform of  claim 5 , wherein the sensors comprise two load cell pairs and two springs and the load cells are located in the Anterior(A)/Posterior(P) and Medial(M)/Lateral(L) planes with respect to the ankle supported on the footplate. 
     
     
         7 . The robotic ankle and balance training platform of  claim 4 , wherein:
 the sensors are capable of measuring a center of pressure on the footplate.   
     
     
         8 . The robotic ankle and balance training platform of  claim 4 , wherein:
 the sensors are capable of measuring at least one of the assistive inversion/eversion force, the resistive inversion/eversion force, the assistive plantar/dorsiflexion force, and the resistive plantar/dorsiflexion force.   
     
     
         9 . The robotic ankle and balance training platform of  claim 1 , wherein the plantar/dorsiflexion axis is offset between approximately 20% and 40% of a length of the footplate from an end of the footplate. 
     
     
         10 . The robotic ankle and balance training platform of  claim 1 , further comprising:
 a mechanical stop to physically limit at least one of inversion/eversion and plantar/dorsiflexion movement of the footplate.   
     
     
         11 . The robotic ankle and balance training platform of  claim 2 , further comprising:
 a first pair of shafts substantially aligned with the inversion/eversion axis, wherein capheads on the first pair of shafts are counter sunk in the inversion/eversion frame; and   a second pair of shafts substantially aligned with the plantar/dorsiflexion axis, wherein capheads of the second pair of shafts are counter sunk in the plantar/dorsiflexion frame.   
     
     
         12 . The robotic ankle and balance training platform of  claim 1 , wherein the actuator system further comprises:
 at least one of an inversion/eversion motor and a plantar/dorsiflexion motor.   
     
     
         13 . The robotic ankle and balance training platform of any of  claims 12 , wherein the at least one motor comprises:
 a pulley assembly;   a gearbox to transfer force to the footplate via the pulley assembly.   
     
     
         14 . The robotic ankle and balance training platform of  claim 1 , further comprising:
 an encoder positioned to read at least one of an inversion/eversion position of the footplate and a plantar/dorsiflexion position of the footplate.   
     
     
         15 . A robotic ankle and balance training device comprising:
 a robotic first ankle and balance training platform according to  claim 1 ;   a robotic second ankle and balance training platform according to  claim 1 .   
     
     
         16 . The robotic ankle and balance training device of  claim 15 , further comprising:
 a controller for determining a desired force for at least one of the assistive forces and the resistive forces and instructing the actuator system of at least one of the robotic platform to provide the desired force to the footplate of the at least one of the robotic platforms.   
     
     
         17 . The robotic ankle and balance training device of  claims 16 , further comprising:
 a sliding track, wherein the sliding track is configured to allow a distance between the first and second robotic platforms to be adjusted.   
     
     
         18 . The robotic ankle and balance training device of  claim 14 , further comprising:
 a stationary platform to house the first and second robotic platforms;   a safety rail connected to the stationary platform;   a lift-assist chair to allow use of the first and second robotic platforms in a seated or a standing position; and   a virtual reality interface configured to interface with the first and second robotic platforms and provide feedback in response to at least one of a footplate orientation and a force asserted by the foot.   
     
     
         19 . The robotic ankle and balance training device of  claim 18 , wherein at least one of the robotic platforms actuates in response to at least one of the force asserted by the foot and the feedback from the virtual reality interface. 
     
     
         20 . The robotic ankle and balance training device of  claim 18 , wherein the virtual reality interface is configured to provide visual feedback in response to a center of pressure measurement to at least one of the robotic platforms. 
     
     
         21 . A method of ankle and balance training comprising:
 measuring a range of motion of an ankle in at least four directions and in a circular motion using a robotic ankle and balance training platform;   measuring a maximum exertion of the ankle in at least the four directions using the robotic platform;   determining a fatigue point of the ankle at approximately 20% of the maximum exertion using the robotic platform; and   detecting a weight shift of a patient using the robotic platform.   
     
     
         22 . The method of ankle and balance training of  claim 21 , wherein the weight shift is detected while a footplate of the robotic platform is stationary. 
     
     
         23 . The method of ankle and balance training of  claim 22 , wherein the weight shift is detected while a footplate of the robotic platform is rotating about one or more of an inversion/eversion axis and a plantar/dorsiflexion axis. 
     
     
         24 . A method of ankle and balance training comprising:
 placing a foot on a robotic ankle and balance training platform of  claim 1 ; and   receiving a visual feedback from a visual interface based on at least one of an orientation of the foot on the robotic platform and a force asserted by the foot against the robotic platform.