Powered prosthesis with torque dense, low ratio actuation

Abstract

Disclosed herein are embodiments of a powered prosthesis. In one embodiment, the powered prosthesis may include a first joint actuator; a second joint actuator; a connector to connect the first joint actuator with the second joint actuator; and a power source connected with both the first and second joint actuator; wherein the first joint actuator and the second joint actuator are both at least backdrivable and configured such that when one of the first or second joint actuator is drawing power from the power source, the other of the first or second joint actuator may be generating power for the power source. In some embodiments, the first motor is at least a high output torque motor. In other embodiments, the second motor is at least a high output torque motor.

1 . A powered prosthesis, comprising:
 a first joint actuator, the first joint actuator including:
 a first high output torque motor having a peak output torque measured over a 10 second time period of at least about 1.0 Nm; and 
 a first transmission coupled with the first high output torque motor, the first transmission having transmission gear ratio of less than or equal to 32 to 1, the first high output torque motor and the first transmission providing the first joint actuator with a static backdrive torque of less than 10 Nm; and 
   a power source connected with the first high output torque motor.   
     
     
         2 . The powered prosthesis according to  claim 1 , wherein the first joint actuator has a mechanical impedance including an inertia of 0.0696 kg·m2 or less and a damping of 0.4169 Nms/rad or less. 
     
     
         3 . The powered prosthesis according to  claim 1 , wherein the powered prosthesis has a peak acoustic noise of less than 60 dB at 0.9 m/s. 
     
     
         4 . The powered prosthesis according to  claim 1 , wherein the power prosthesis has a peak acoustic noise of less than 65 dB at 1.3 m/s. 
     
     
         5 . The powered prosthesis according to  claim 4 , wherein the first high output torque motor is a first very high output torque motor having a peak output torque measured over a 10 second time period of at least about 1.5 Nm, the first joint actuator further including a first housing having the first very high output torque motor, the first transmission positioned co-axially within the housing. 
     
     
         6 . The powered prosthesis according to  claim 1 , wherein the first transmission is a single-stage stepped-planet compound planetary gear transmission. 
     
     
         7 . The powered prosthesis according to  claim 1 , further including a second joint actuator, wherein the second joint actuator includes a second housing having a second motor and a second transmission positioned co-axially within the second housing. 
     
     
         8 . The powered prosthesis according to  claim 7 , wherein the second motor is a second very high output torque motor having a peak output torque measured over a 10 second time period of at least about 1.5 Nm. 
     
     
         9 . The powered prosthesis according to  claim 7 , wherein the second joint actuator further includes a link system connecting the second joint actuator with a joint plate, and a 6-axis load cell coupled with the joint plate, and further including a connector to connect the first joint actuator with the second joint actuator. 
     
     
         10 . The powered prosthesis according to  claim 7 , wherein the second transmission includes a plurality of planetary gears. 
     
     
         11 . The powered prosthesis according to  claim 1 , wherein at least one of the first and second joint actuators is very backdrivable, and thereby has a static backdrive torque less than 5 Nm. 
     
     
         12 . The powered prosthesis according to  claim 1 , wherein at least one of the first and second joint actuators is excessively backdrivable, and thereby has a static backdrive torque less than 2.0 Nm. 
     
     
         13 . A powered prosthesis, comprising:
 a first joint actuator, the first joint actuator including a first motor and a first transmission axially aligned with the first motor, wherein the first motor is a first high output torque motor having a peak output torque measured over a 10 second time period of at least about 1.0 Nm; and   a second joint actuator, the second joint actuator including a second motor and a second transmission axially aligned with the second motor, wherein the second motor is a second high output torque motor having a peak output torque measured over a 10 second time period of at least about 1.0 Nm, wherein at least one of the first and second joint actuators is backdrivable, and thereby has a static backdrive torque less than about 10 Nm.   
     
     
         14 . The powered prosthesis according to  claim 13 , wherein the first joint actuator has a mechanical impedance including an inertia of 0.0696 kg·m2 or less and a damping of 0.4169 Nms/rad or less. 
     
     
         15 . The powered prosthesis according to  claim 13 , wherein the powered prosthesis has a peak acoustic noise of less than 60 dB at 0.9 m/s and a peak acoustic noise of less than 65 dB at 1.3 m/s. 
     
     
         16 . The powered prosthesis according to  claim 13 , wherein the first and second high output torque motors are first and second very high output torque motors having a peak output torque measured over a 10 second time period of at least 1.5 Nm. 
     
     
         17 . The powered prosthesis according to  claim 13 , wherein the first and second high output torque motors are first and second extremely high output torque motors having a peak output torque measured over a 10 second time period of at least 2.0 Nm. 
     
     
         18 . The powered prosthesis according to  claim 13 , wherein at least one of the first joint actuator or the second joint actuator is a quasi-direct drive actuator having a transmission gear ratio of less than or equal to 24 to 1. 
     
     
         19 . The powered prosthesis according to  claim 13 , wherein at least one of the first transmission or the second transmission has a transmission gear ratio of less than or equal to 22 to 1. 
     
     
         20 . The powered prosthesis according to  claim 13 , wherein both of the first and second joint actuators are backdrivable, and thereby have a static torque less than 10 Nm. 
     
     
         21 . The powered prosthesis according to  claim 13 , wherein the first transmission is a single-stage stepped-planet compound planetary gear transmission.