Jointed mechanical devices
A jointed mechanical device is provided. The device includes at least one element having a fixed end and a deflectable end. The device also includes at least one actuating structure having a first end coupled to at least the deflectable end of the element, where the actuating structure includes at least one elastic element in series with at least one non-elastic element. The device further includes at least one force actuator configured to apply an actuator force to a second end of the actuating structure. Additionally, the device includes a control system for adjusting an operation of the force actuator based at least one actuation input, an amount of the actuator force, and an amount of displacement generated by the force actuator.
1. A prosthetic device, comprising:
a member configured for attachment to a residual limb;
a hand device coupled to the member, said hand device comprising a base, at least one force actuator, at least one digit pivotably coupled to said base, said digit comprising a plurality of phalangeal portions connected by a plurality of flexible joint portions, at least one actuating structure having a first end coupled to a distal end of said digit and a second end coupled to the at least one force actuator, said actuating structure comprising at least one elastic element in series with at least one non-elastic element, and at least one force actuator configured to apply an actuator force to a second end of said at least one actuating structure; and
a control system for operating said force actuator, the control system comprising a processor and a computer-readable medium having stored thereon a plurality of instructions for causing the processor to perform the method comprising: receiving at least one control signal associated with said at least one force actuator; and initiating an operation of the at least one force actuator according to the at least one control signal, the operation comprising:
determining, based on at least actuator signal from the at least one force actuator, an amount of said actuator force applied by said at least one force actuator to said second end of said at least one actuating structure and an amount of displacement of said actuating structure generated by said at least one force actuator,
determining a relationship between said amount of actuator force and said amount of displacement based on stiffness values associated with said at least one actuating structure, and
adjusting a mode of said operation of said at least one force actuator to one of a force control mode or a motion control mode based on said relationship between said amount of said actuator force and said amount of displacement.
2. The prosthetic device of claim 1 , wherein the member comprises a socket for attaching the at least one member to the residual limb.
3. The prosthetic device of claim 2 , further comprising a plurality of electromyogram (EMG) sensors for generating said at least one control signal based on EMG signals from said residual limb.