Difference between revisions of "Torque-feedback controller"
From DIDEAS Wiki
(Created page with "== Torque feedback algorithm == *The torque command from the ankle is a function of ankle state. Specifically: T_out = STATE[Kes*Theta + Bes*Thetadot] + LS,LSP[Kls*Theta + Bls*T...") |
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*PCI = Power curve intercept (based on subject's weight (see tuning interface for details on setting weight) | *PCI = Power curve intercept (based on subject's weight (see tuning interface for details on setting weight) | ||
*Exp = Exponent | *Exp = Exponent | ||
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*T_meas is determined by taking the difference between the motor encoder position and the output ankle joint position, using the measured series spring constant to determine ankle torque. | *T_meas is determined by taking the difference between the motor encoder position and the output ankle joint position, using the measured series spring constant to determine ankle torque. | ||
| + | *T_out is provided using current-control. | ||
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| + | *In practice, it is likely that PFF mainly affects the net work done by the ankle, while Exp mainly affects the timing. This has yet to be verified. | ||
Revision as of 00:35, 12 April 2012
Torque feedback algorithm
- The torque command from the ankle is a function of ankle state. Specifically:
T_out = STATE[Kes*Theta + Bes*Thetadot] + LS,LSP[Kls*Theta + Bls*Thetadot] + LSP[PFF/PCI*T_meas^Exp]
- ES[expression] means the expression is only executed during the specified STATE (ES=early stance, LS=late stance, LSP=late stance power)
- T_out = output torque command
- T_meas = measured torque
- Theta, Thetadot = Ankle angle, angular velocity (positive = dorsiflexion)
- Kes, Bes = Virtual spring, damper constants for early stance
- Kls, Bls = Virtual spring, damper constants for late stance
- PFF = Positive force feedback gain
- PCI = Power curve intercept (based on subject's weight (see tuning interface for details on setting weight)
- Exp = Exponent
- T_meas is determined by taking the difference between the motor encoder position and the output ankle joint position, using the measured series spring constant to determine ankle torque.
- T_out is provided using current-control.
- In practice, it is likely that PFF mainly affects the net work done by the ankle, while Exp mainly affects the timing. This has yet to be verified.
