Muscle or Actuator to use in order to model a motor

[Pierre HE]

Hello,

I am currently trying to model a motor. I thought of a CoordinateActuator. However I can only set the value for excitation and I can not set the power. I need to put a value for the max force and the max speed.
Actually when I add an input to the coordinate actuator in Scone, I have a coordinate which moves instantly, a lot faster than it is physically possible. Is there a way I can model my motor ?

My motor displays constant power, however the speed and force depend on each other.

I tried to model my motor with a millard2012equilibriummuscle, however I encounter error because I used a PointConstraint. I can not avoid the use of the PointConstraint because I a loop of joint.

Thank you !

[Thomas Geijtenbeek]

I don't think you should model your motor with a muscle model. Your best bet indeed seems to be a CoordinateActuator. The moment it generates depends on the optimal_force value set in the actuator: moment = input * optimal_force.

I'm not sure what causes the issue you are seeing. Does the model function normally if you simulate it in OpenSim? If not, the issue is with the OpenSim model and not with SCONE.

[Pierre HE]

Thanks for the answer.

The problem I have with the coordinate actuator is that I cannot set the value for the maximum speed it can reach.
Actually my motor cannot turn faster than a certain speed. And I have noticed that we can only set the force, but not the speed. And thus during the simulation, my motor turns a lot faster than it us supposed to.

Is there a way to set the max speed with the coordinateactuator ?

[Thomas Geijtenbeek]

I don't think you can set the max speed, but you can adjust the input based on the current speed to prevent it from going faster.

[Pierre HE]

Actually, I always set max power when activating the motor. The motor helps raising a part of the body. I do forward simulation to evaluate how the motor behaves with the body. Thus I don't know the moment(from the motor) needed in order to achieve the movement I want to do. The speed is supposed to regulate itself depending on the force needed to do the movement.

Is there a way to set this up ?

[Thomas Geijtenbeek]

Did you manage to solve the issue?