Tunable Actuator Joint Modules Having Energy Recovering Quasi-Passive Elastic Actuators for Use within a Robotic System

Abstract

A tunable actuator joint module of a robotic assembly comprises an output member and an input member, where the output member is rotatable about an axis of rotation. A primary actuator (e.g., a motor) is operable to apply a torque to rotate the output member about the axis of rotation. A quasi-passive elastic actuator (e.g., rotary or linear pneumatic actuator) comprising an elastic component is tunable to a joint stiffness value and is operable to selectively release stored energy to apply an augmented torque to assist rotation of the output member and to minimize power consumption of the primary actuator. The tunable actuator joint module comprises a control system having a valve assembly controllably operable to switch the quasi-passive elastic actuator between an elastic state and an inelastic state during respective portions of movement of the robotic assembly (e.g., a hip or knee joint of an exoskeleton). Associated systems and methods are provided.

What is claimed is: 
     
         1 . A tunable actuator joint module of a robotic assembly, comprising:
 an output member operable to couple to a first support member of a robotic system;   an input member operable to couple to a second support member of the robotic system;   a primary actuator operable to apply a torque to rotate the output member about an axis of rotation; and   a quasi-passive elastic actuator comprising an elastic component dynamically tunable to a joint stiffness value, the quasi-passive elastic actuator operable to selectively store energy upon a first rotation of the input member, and to selectively release energy upon a second rotation of the input member to apply an augmented torque that combines with the torque from the primary actuator to assist rotation of the output member during the second rotation.   
     
     
         2 . The tunable actuator joint module of  claim 1 , further comprising a control system operatively coupled to the quasi-passive elastic actuator for selectively controlling application of the augmented torque. 
     
     
         3 . The tunable actuator joint module of  claim 2 , wherein the control system comprises a valve assembly operable to switch the quasi-passive elastic actuator between an elastic state, a semi-elastic state and an inelastic state, wherein in the elastic state, the quasi-passive elastic actuator operates to store and release the energy, wherein in the semi-elastic state, the quasi-passive elastic actuator operates in a damping mode, and wherein in the inelastic state, the quasi-passive elastic actuator operates in a free-swing mode. 
     
     
         4 . The tunable actuator joint module of  claim 3 , wherein the quasi-passive elastic actuator comprises a compression chamber and an expansion chamber, and wherein the valve assembly and the elastic component define a shunt circuit that facilitates fluid flow between the compression and expansion chambers through the valve assembly. 
     
     
         5 . The tunable actuator joint module of  claim 1 , wherein the elastic component comprises a housing, at least a portion of which is operable to be charged to a selected gas pressure to define a predefined joint stiffness value. 
     
     
         6 . The tunable actuator joint module of  claim 5 , wherein the quasi-passive elastic actuator comprises a rotary pneumatic actuator, and wherein the elastic component further comprises a first vane device and second vane device rotatable relative to each other within the housing, the first vane device and second vane device defining, at least in part, a compression chamber and an expansion chamber. 
     
     
         7 . The tunable actuator joint module of  claim 6 , wherein the first vane device is rotatable with the input member and the second vane device is rotatable with the output member such that, upon the first rotation, gas is compressed in the compression chamber between the first vane device and the second vane device to store energy, and such that, upon the second rotation, gas is expanded in the compression chamber to release stored energy to apply the augmented torque to assist in actuation of the output member. 
     
     
         8 . The tunable actuator joint module of  claim 6 , wherein the second vane device is selectively positioned relative to the first vane device. 
     
     
         9 . The tunable actuator joint module of  claim 6 , wherein the first vane device is positioned 180 degrees from the second vane device in a nominal position, such that the compression and expansion chambers comprise substantially equal volumes. 
     
     
         10 . The tunable actuator joint module of  claim 6 , wherein the first vane device is positioned greater or less than 180 degrees from the second vane device in a nominal position, such that the compression and expansion chambers comprise disparate volumes. 
     
     
         11 . The tunable actuator joint module of  claim 6 , wherein the compression and expansion chambers are collectively gas pressure charged to a nominal gas pressure to define a predetermined joint stiffness value. 
     
     
         12 . The tunable actuator joint module of  claim 6 , wherein the valve assembly comprises a valve device disposed through an opening of the first vane device, wherein the valve device is variably controllable to open and close a shunt circuit and to switch the quasi-passive actuator joint module between the elastic and inelastic states. 
     
     
         13 . The tunable actuator joint module of  claim 12 , wherein the valve assembly comprises a valve actuator operatively coupled to the valve device to facilitate selective actuation of the valve device, the valve device comprising an open position that opens the shunt circuit to permit fluid flow between the expansion and compression chambers and the valve assembly, a closed position that closes the shunt circuit to restrict fluid flow between the expansion and compression chambers and the valve assembly, and a partially open position that partially restricts fluid flow between the expansion and compression chambers to facilitate a damping mode. 
     
     
         14 . The tunable actuator joint module of  claim 13 , wherein the valve device comprises at least one fluid opening through which fluid flows when in the open position to equalize gas pressure between the compression and expansion chambers, and wherein the first vane device comprises a compression chamber conduit in fluid communication with the compression chamber, and an expansion chamber conduit in fluid communication with the expansion chamber, wherein the compression chamber conduit and the expansion chamber conduit are in fluid communication with each other and the fluid opening in the valve device when the valve device is in the open position. 
     
     
         15 . The tunable actuator joint module of  claim 12 , wherein the valve device comprises an axis collinear with the axis of rotation of the tunable actuator joint module. 
     
     
         16 . The tunable actuator joint module of  claim 6 , wherein the rotary pneumatic actuator and the primary actuator each have a central axis of rotation substantially parallel to each other. 
     
     
         17 . The tunable joint module of  claim 5 , wherein the quasi-passive elastic actuator comprises a linear pneumatic actuator, and wherein the elastic component further comprises a piston rod and a piston cylinder moveable in a linear motion within the housing, the piston cylinder defining, at least in part, a compression chamber and an expansion chamber. 
     
     
         18 . The tunable joint module of  claim 17 , further comprising an output device comprising the output member and a gear ring, wherein the primary actuator comprises an electric motor and an output pulley, wherein the output pulley and the gear ring are rotatably coupled by a torque-transfer device. 
     
     
         19 . The tunable joint module of  claim 18 , wherein the linear pneumatic actuator comprises the input member, wherein the piston rod is pivotally coupled to the output device at an off-center position, such that, upon the first rotation, movement of the input member causes the piston cylinder to move to compress gas in the compression chamber to selectively store energy. 
     
     
         20 . The tunable joint module of  claim 18 , wherein the output device and the primary actuator each have a central axis of rotation parallel to each other. 
     
     
         21 . The tunable joint module of  claim 17 , wherein, upon the second rotation, the linear pneumatic actuator releases energy via the piston rod to apply the augmented torque to the output device in parallel with the primary torque applied by the primary actuator. 
     
     
         22 . The tunable joint module of  claim 17 , wherein the primary actuator comprises a motor having a central void and a transmission rotatably coupled to the motor, and wherein the transmission is at least partially disposed within the central void of the motor. 
     
     
         23 . The tunable joint module of  claim 17 , wherein the linear pneumatic actuator is configured to apply the augmented torque to one of a joint of the robotic system corresponding to a knee joint or a joint of the robotic system corresponding to an ankle joint, or a joint of the robotic system corresponding to a hip joint, each being rotatable during at least a portion of a gait cycle. 
     
     
         24 . The tunable joint module of  claim 1 , further comprising a planetary drive transmission rotatably coupled to the primary actuator, the planetary drive transmission being at least partially disposed within a central void of the primary actuator. 
     
     
         25 . The tunable joint module of  claim 1 , further comprising a torque-transfer device rotatably coupled between an output pulley of the primary actuator and an input pulley of the quasi-passive elastic actuator, wherein the input pulley is coupled to the output member about the axis of rotation. 
     
     
         26 . The tunable joint module of  claim 25 , wherein the output pulley has a different diameter than a diameter of the input pulley to define a two-stage transmission. 
     
     
         27 . The tunable joint module of  claim 1 , wherein the compression and expansion chambers are collectively gas pressure charged to define the predetermined joint stiffness value of the tunable actuator joint module. 
     
     
         28 . A tunable actuator joint module of a robotic assembly, comprising:
 an output member operable to couple to a first support member of a robotic system;   an input member operable to couple to a second support member of the robotic system;   a primary actuator operable to apply a torque to rotate the output member about an axis of rotation; and   a quasi-passive elastic actuator comprising an elastic component dynamically tunable to a joint stiffness value, the quasi-passive elastic actuator comprising an elastic state, a semi-elastic state, and an inelastic state.   
     
     
         29 . The tunable actuator joint module of  claim 28 , wherein in the elastic state, the quasi-passive elastic actuator stores energy during a rotation of the input member, and releases energy during a subsequent rotation of the input member to apply an augmented torque to the output member. 
     
     
         30 . The tunable actuator joint module of  claim 28 , wherein in the semi-elastic state, the quasi-passive elastic actuator operates in a damping mode to provide a damping force or a braking force to the tunable actuator joint module. 
     
     
         31 . The tunable actuator joint module of  claim 30 , wherein, in the semi-elastic state, the braking or damping force is variable. 
     
     
         32 . The tunable actuator joint module of  claim 28 , wherein in the inelastic state, the quasi-passive elastic actuator neither stores nor releases energy, and operates in a free-swing mode. 
     
     
         33 . The tunable actuator joint module of  claim 28 , wherein the quasi-passive elastic actuator is selectively switchable in real-time between the elastic, semi-elastic and inelastic states. 
     
     
         34 . The tunable actuator joint module of  claim 33 , further comprising a valve assembly operable to selectively control switching in real-time between the elastic, semi-elastic and inelastic states. 
     
     
         35 . The tunable actuator joint module of  claim 28 , wherein the valve assembly opened, closed, or partially opened a variable degree.