Clutched Joint Modules for a Robotic System

Abstract

A clutched joint module comprising an output member and an input member rotatable relative to each other about an axis of rotation; a primary actuator operable to apply a primary torque to rotate the output member about the axis of rotation; and a clutch mechanism operable between an engaged state and a disengaged state to facilitate application of the primary torque. The clutch mechanism can comprise a plurality of plates and an actuator operable to compress the plurality of plates to cause the clutch mechanism to function in the engaged state. The actuator can be a ball-ramp clutch device. A quasi-passive elastic actuator can be coupled to the input member and can be operable, via the clutch mechanism, to release stored energy to apply an augmented torque to assist rotation of the output member. Associated methods and systems are disclosed.

What is claimed is: 
     
         1 . A method for operating a robotic joint of a robotic system, the method comprising:
 operating a clutch mechanism of a clutched joint module defining a joint of the robotic system between an engaged state, a semi-engaged state, and a disengaged state, wherein the clutch mechanism is operably coupled between input and output members of the clutched joint module; and   rotating a first support member of the robotic system coupled to the output member relative to a second support member coupled to the input member, thus rotating the joint about an axis of rotation;   
     
     
         2 . The method of  claim 1 , wherein rotating the first support member relative to the second support member comprises actuating a primary actuator of the clutched joint module with the clutched mechanism in the engaged or semi-engaged state to apply a primary torque to the output member, wherein the clutched mechanism functions to transfer at least a portion of the primary torque from the primary actuator to the output member and rotate the joint. 
     
     
         3 . The method of  claim 1 , wherein rotating the first support member relative to the second support member comprises passively rotating these with the clutched mechanism in the engaged or semi-engaged state in response to an external force, thereby generating a braking force operable to resist rotation of the joint. 
     
     
         4 . The method of  claim 1 , further comprising operating the clutch mechanism in the disengaged state, wherein the joint enters a free swing mode. 
     
     
         5 . The method of  claim 1 , further comprising operating a quasi-passive elastic actuator of the clutched joint module in an elastic state or semi-elastic state by selectively engaging the clutch mechanism to generate and apply an augmented torque to the output member. 
     
     
         6 . The method of  claim 1 , further comprising operating a quasi-passive elastic actuator of the clutched joint module in an elastic state or semi-elastic state by selectively engaging the clutch mechanism to generate a braking force within the clutched joint module. 
     
     
         7 . The method of  claim 1 , further comprising operating a quasi-passive elastic actuator of the clutched joint module in an inelastic state to cause the clutched joint module to enter a free swing mode. 
     
     
         8 . The method of  claim 5 , further comprising pre-charging the quasi-passive elastic actuator to a predetermined stiffness. 
     
     
         9 . A clutched joint module for use within 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 the primary actuator comprising a motor and a transmission; and   a clutch mechanism operably coupled between the input member and the output member, the clutch mechanism operable in an engaged state, a semi-engaged state, or a disengaged state, wherein the engaged state and the semi-engaged state facilitate selective application of the primary torque to the output member,   wherein the clutch mechanism, the motor, and the transmission are arranged along and operable about the axis of rotation.   
     
     
         10 . The clutched joint module of  claim 9 , wherein clutch mechanism is operable in the engaged or semi-engaged state to generate a variable braking force for restricting rotation between the input and output members either with or without the primary torque. 
     
     
         11 . The clutched joint module of  claim 9 , wherein the clutch mechanism comprises a plurality of plates and an actuator operable to compress the plurality of plates to cause the clutch mechanism to function in the engaged state or the semi-engaged state. 
     
     
         12 . The clutched joint module of  claim 9 , wherein at least a portion of the clutch mechanism comprises a clutch axis of rotation substantially collinear with the axis of rotation. 
     
     
         13 . The clutched joint module of  claim 9 , wherein the transmission is at least partially disposed within a central void of the motor. 
     
     
         14 . The clutched joint module of  claim 9 , wherein the motor comprises a brushless frameless electric motor. 
     
     
         15 . The clutched joint module of  claim 9 , further comprising a quasi-passive elastic actuator coupled to the input member and arranged in parallel with the primary actuator, the quasi-passive elastic actuator operable to store and release energy upon the clutch mechanism being engaged or semi-engaged. 
     
     
         16 . The clutched joint module of  claim 15 , wherein the quasi-passive elastic actuator operates to generate a braking force to at least partially restrict rotation between the input and output members. 
     
     
         17 . The clutched joint module of  claim 15 , wherein the quasi-passive elastic actuator operates to apply an augmented torque to be combined with a primary torque generated by the primary actuator to assist in rotation of the output member. 
     
     
         18 . The clutched joint module of  claim 15 , wherein the quasi-passive elastic actuator comprises a quasi-passive linear pneumatic actuator. 
     
     
         19 . The clutched joint module of  claim 18 , wherein the quasi-passive linear pneumatic actuator is gas pressure charged to at least partially define a joint stiffness value of the clutched joint module. 
     
     
         20 . The clutched joint module of  claim 15 , wherein the quasi-passive elastic actuator is selectively switchable in real-time between an elastic state, a semi-elastic state, and an inelastic state via the clutch mechanism. 
     
     
         21 . The clutched joint module of  claim 9 , wherein the clutch mechanism comprises:
 a clutch housing coupled to the input member;   a plurality of input plates retained by the clutch housing;   a plurality of output plates rotatably supported by the clutch housing and rotatably engaged with the plurality of input plates; and   an actuator operable to apply a compression force to the output plates and the input plates, upon receiving the clutch control signal, to cause the clutch mechanism to operate in the engaged state.   
     
     
         22 . The clutched joint module of  claim 21 , wherein the output member is coupled to the plurality of output plates, such that, when the clutch mechanism is in the disengaged state, the output plates freely rotate relative to the input plates. 
     
     
         23 . The clutched joint module of  claim 21 , wherein the primary actuator comprises a motor, and wherein the clutched joint module further comprises a first transmission disposed at least partially within the motor and a second transmission operatively coupled between the first transmission and the clutch mechanism. 
     
     
         24 . The clutched joint module of  claim 9 , wherein the clutch mechanism comprises:
 a clutch housing coupled to the input member;   a plurality of input plates retained by the clutch housing;   a plurality of output plates rotatably supported by the clutch housing and rotatably engaged with the plurality of input plates;   a ball-ramp clutch device coupled to the clutch housing; and   an actuator coupled to the ball-ramp clutch device and operable to rotate the ball-ramp clutch device, upon receiving a control signal, to apply a compression force to the output plates and the input plates to cause the clutched mechanism to operate in the engaged state.   
     
     
         25 . The clutched joint module of  claim 24 , wherein the clutch mechanism further comprises an output shaft coupled to the plurality of output plates, such that, when the clutch mechanism is in the disengaged state, the output plates freely rotate relative to the input plates. 
     
     
         26 . The clutched joint module of  claim 24 , wherein the primary actuator comprises a motor, and wherein the clutched joint module further comprises a first transmission disposed at least partially within the motor, and a second transmission operatively coupled between the first transmission and the clutch mechanism. 
     
     
         27 . A robotic system comprising a robotic limb having at least one rotatable joint, the robotic assembly comprising:
 a plurality of support members; and   a plurality of clutched joint modules defining respective joints of the robotic limb, each clutched joint module rotatably coupling together at least two of the plurality of support members, and comprising:
 a joint rotatable about an axis of rotation and defining a degree of freedom; 
 a primary actuator operable to apply a primary torque to rotate the joint, the primary actuator comprising a motor and a transmission; and 
 a clutch mechanism coupled to the primary actuator and operable between an engaged state, a semi-engaged state and a disengaged state, wherein the engaged state and the semi-engaged state facilitate selective application of the primary torque to rotate the joint, wherein the clutch mechanism, the motor, and the transmission are arranged along and operable about the axis of rotation. 
   
     
     
         28 . The robotic system of  claim 27 , wherein the clutch mechanism is operable in the engaged or semi-engaged state to generate a braking force for restricting rotation of the joint either with or without the primary torque. 
     
     
         29 . The robotic system of  claim 27 , wherein the transmission is operatively coupled to the motor. 
     
     
         30 . The robotic system of  claim 27 , further comprising a quasi-passive elastic actuator operable with the clutch mechanism and arranged in parallel with the primary actuator, the quasi-passive elastic actuator operable to store and release energy upon the clutch mechanism being engaged or semi-engaged. 
     
     
         31 . The robotic system of  claim 30 , wherein the quasi-passive elastic actuator operates to generate a braking force to at least partially restrict rotation between the input and output members. 
     
     
         32 . The robotic system of  claim 30 , wherein the quasi-passive elastic actuator operates to apply an augmented torque to be combined with a primary torque generated by the primary actuator to assist in rotation of the joint. 
     
     
         33 . The robotic assembly of  claim 27 , wherein one of the plurality of clutched joint modules comprises a quasi-passive elastic actuator comprising an elastic element of a first type, and wherein another one of the plurality of clutched joint modules comprises a quasi-passive elastic actuator comprising an elastic element of a different type. 
     
     
         34 . The robotic assembly of  claim 30 , wherein the quasi-passive elastic actuator is selectively switchable in real-time between an elastic state, a semi-elastic state, and an inelastic state via the clutch mechanism. 
     
     
         35 . A clutched joint module for use within 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 the primary actuator comprising a motor and a transmission; and   a clutch mechanism operably coupled between the input member and the output member, the clutch mechanism operable in an engaged state, a semi-engaged state, or a disengaged state, wherein the engaged state and the semi-engaged state facilitate selective application of the primary torque to the output member,   wherein the transmission is at least partially disposed within a central void of the motor.   
     
     
         36 . The clutched joint module of  claim 35 , further comprising a quasi-passive elastic actuator coupled to the input member and arranged in parallel with the primary actuator, the quasi-passive elastic actuator operable to store and release energy upon the clutch mechanism being engaged or semi-engaged. 
     
     
         37 . The clutched joint module of  claim 15 , wherein the quasi-passive elastic actuator is selectively switchable in real-time between an elastic state, a semi-elastic state, and an inelastic state via the clutch mechanism. 
     
     
         38 . The clutched joint module of  claim 9 , wherein the clutch mechanism comprises:
 a clutch housing coupled to the input member;   a plurality of input plates retained by the clutch housing;   a plurality of output plates rotatably supported by the clutch housing and rotatably engaged with the plurality of input plates; and   an actuator operable to apply a compression force to the output plates and the input plates, upon receiving the clutch control signal, to cause the clutch mechanism to operate in the engaged state.   
     
     
         39 . The clutched joint module of  claim 9 , wherein the clutch mechanism comprises:
 a clutch housing coupled to the input member;   a plurality of input plates retained by the clutch housing;   a plurality of output plates rotatably supported by the clutch housing and rotatably engaged with the plurality of input plates;   a ball-ramp clutch device coupled to the clutch housing; and   an actuator coupled to the ball-ramp clutch device and operable to rotate the ball-ramp clutch device, upon receiving a control signal, to apply a compression force to the output plates and the input plates to cause the clutched mechanism to operate in the engaged state.