Powered prosthetic flexion device
Technology is described to provide a powered prosthetic wrist flexion device or elbow device. This device helps individuals with upper-limb loss to orient and position grasped objects.
1. An electrically powered prosthetic joint, comprising:
a housing to contain a prosthetic joint for an amputee;
a motor attached to the housing;
a two-stage friction planetary drive having planet gears that are bushings, that is powered by the motor;
a ring of the two-stage friction planetary drive that is common to a first stage and a second stage of the two-stage friction planetary drive;
an output drive shaft driven by the two-stage friction planetary drive, wherein the output drive shaft moves a prosthetic wrist joint; and
a series elastic element to reduce stiffness and frequency in a drive train to provide high frequency motor control and torque control.
2. The electrically powered prosthetic joint as in claim 1 , wherein the two-stage friction planetary drive includes planet gears that are low friction bushings with reduced size shafts as compared to a size of the low friction bushings, a sun gear that is a pin and the ring is a cylinder bushing.
3. The electrically powered prosthetic joint as in claim 1 , further comprising ball bearings for the first stage and second stage of planet gears to act as thrust bearings.
4. The electrically powered prosthetic joint as in claim 1 , further comprising a motor controller utilizing a power save process that senses stall through monitoring distal and proximal motor position or angular velocity.
5. The electrically powered prosthetic joint as in claim 1 , wherein the motor is a brushless DC motor that is mounted on O-rings.
6. The electrically powered prosthetic joint as in claim 1 that is controlled to exhibit active compliance through use of a hybrid position and force controller.
7. The electrically powered prosthetic joint as in claim 1 , further comprising a controller that senses stall of the motor through monitoring stall current and reduces power to the motor when stalling occurs.
8. The electrically powered prosthetic joint as in claim 1 , further comprising an extension stop.
9. The electrically powered prosthetic joint as in claim 1 , further comprising an output drive that exits the housing as a revolving shaft, wherein the revolving shaft is sealed for dirt, water and sound.
10. An electrically powered prosthetic joint, comprising:
a housing to provide a prosthetic joint for an amputee;
a motor attached to the housing;
a two-stage friction planetary drive having planetary gears that are bushings, that is powered by the motor;
a ring around the two-stage friction planetary drive that is common to a first stage and a second stage of the two-stage friction planetary drive, wherein the two-stage friction planetary drive includes planet gears with low friction bushings with reduced size shafts as compared to a size of the low friction bushings;
an output drive shaft driven by the two-stage friction planetary drive, wherein the output drive shaft moves a prosthetic wrist; and
a series elastic element coupled to the output drive shaft to reduce stiffness and frequency in a drive train and to provide high frequency torque control.
11. The electrically powered prosthetic joint as in claim 10 , further comprising ball bearings in the first stage and second stage to act as thrust bearings.
12. The electrically powered prosthetic joint as in claim 10 , further comprising a servo clamp on the output drive shaft that is configured to break away under a defined amount of load to act as overload protection.
13. The electrically powered prosthetic joint as in claim 10 , wherein the motor is a brushless DC motor that is mounted on O-rings.
14. An electrically powered prosthetic joint, comprising:
a housing to contain a prosthetic joint for an amputee;
a motor attached to the housing;
a two-stage friction planetary drive having planet gears that are bushings, that is powered by the motor;
a ring of the two-stage friction planetary drive that is common to a first stage and a second stage of the two-stage friction planetary drive; and
an output drive shaft driven by the two-stage friction planetary drive, wherein the output drive shaft moves a prosthetic wrist joint; and
a servo clamp on the output drive shaft, which is configured to break away under a defined amount of load and to act as overload protection for an amputee's remnant limb.
15. The electrically powered prosthetic joint as in claim 14 , further comprising ball bearings for the first stage and second stage of planet gears to act as thrust bearings.
16. An electrically powered prosthetic joint, comprising:
a housing to contain a prosthetic joint for an amputee;
a motor attached to the housing;
a two-stage friction planetary drive having planet gears that are bushings, that is powered by the motor;
a ring of the two-stage friction planetary drive that is common to a first stage and a second stage of the two-stage friction planetary drive;
an output drive shaft driven by the two-stage friction planetary drive, wherein the output drive shaft moves a prosthetic wrist joint; and
a cable that passes through the housing and is routed along an axial channel formed in the output drive shaft, wherein the cable twists along a cable axis to increase wire operational period.
17. An electrically powered prosthetic joint, comprising:
a housing to contain a prosthetic joint for an amputee;
a motor attached to the housing;
a two-stage friction planetary drive having planet gears that are bushings, that is powered by the motor;
a ring of the two-stage friction planetary drive that is common to a first stage and a second stage of the two-stage friction planetary drive;
an output drive shaft driven by the two-stage friction planetary drive, wherein the output drive shaft moves a prosthetic wrist joint; and
output evoloid gears coupled to the output drive shaft, wherein the output evoloid gears reduce a size and noise of a gearing.