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- CMC procedure contains static optimization process, and it tries to minimize the cost function J which can be represented as
- When we add active actuators on OpenSim Model, the activation term in cost function becomes
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- Where X_muscle is muscle control and X_actuator is actuator control. X_actuator is part of activation state, and it is also adjusted after the optimization process.
- Now, if we diminish the influnece of X_actuator on J, and run CMC, the optimizer tries to find X_actuator in order to minimize muscle activation.
- We know that minimizing muscle activation correponds to minimizing metabolic cost, so we can we can say that the actuator input force resulted from CMC after diminishing the influence of X_actuator is the optimal actuator input for most efficient metabolic reduction.
- Muscle force is constructed by the equation
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And if we assign large value of maximum force to each actuator, then actuator control x_actuator decreases, so that the influence of actuator to J is decreases.
- Using this methodology, I could find an optimal input for each actuator, and also see the metabolic cost reduction after active actuators are added to a model.
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- Metabolic cost reduction when active actuators are added to loaded gait model
- Ankle actuator: 10.35%
- Hip actuator: 6.62%
- Metabolic cost reduction when active actuators are added to unloaded gait model
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