Do we have any function that maps current to torque for a given kp and kd value?

Mechanics
1

I am looking for a relation between current and torque.

2

We measured a torque constant of 0.02Nm/A at the motor.
The actuator modules have a 9:1 gear reduction.
So at the output you get approximately 0.18Nm/A.

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3

The curren i send to motor is not same i observed from DC power supply.
For example,If i send 1.4 A to motor,the DC power supply shows that the current maybe is 0.2 A,which is less than 1.4A.

Is there a mapping between desired current and actual current?

4

Hi,
This is a common misconception: The current measured at the power supply is not the current running on the motor, since the voltages are different.

  • The voltage at the DC power supply is kept fixed (24V).
  • The voltage at the motor will depend on the motor velocity, motor resistance and motor current (or torque).

Lets say we have an ideal motor controller, with no power loss, the power is conserved:
U_dc * I_dc = U_mot * I_mot

You can directly read I_mot via the motor controller, which is the image of the torque

1 Like
5

Thanks.
I’ve been confused about this for a while.