Biomimetic joint actuators
AssigneeBionx Medical Technologies, Inc.
InventorsHugh Miller Herr, Jeff Anthony Weber, Richard James Casler
Life of this patent
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Abstract
In a powered actuator for supplying torque, joint equilibrium, and/or impedance to a joint, a motor is directly coupled to a low-reduction ratio transmission, e.g., a transmission having a gear ratio less than about 80 to 1. The motor has a low dissipation constant, e.g., less than about 50 W/(Nm)2. The transmission is serially connected to an elastic element that is also coupled to the joint, thereby supplying torque, joint equilibrium, and/or impedance to the joint while minimizing the power consumption and/or acoustic noise of the actuator.
Claims6
A method for augmenting joint function using a powered human augmentation device, the method comprising:
- energizing a motor in the human augmentation device to apply torque to a joint of the human augmentation device during a phase of a gait cycle to modulate at least one of joint augmentation torque, joint impedance, or joint equilibrium during the phase of the gait cycle, the applied torque normalized by weight to be between −2.8 Nm/kg to 2.8 Nm/kg, the motor coupled directly to a transmission, the transmission being serially coupled to an elastic element, the elastic element coupled to the joint;
- and
- shorting leads of the motor to exert a viscous damping torque on the motor proportional to a motor dissipation constant given by R/k12, where R refers to a stator winding resistance and k1 refers to a motor torque constant, the dissipation constant being less than 50 W/(Nm)2.
Dependencies are inferred from the claim text.