What does exacly the motor when the torque is enabled in current control mode?

ROBOTIS Software

Dynamixel Wizard 2.0

Control Environment

DYNAMIXEL XM540-W270-T connected via U2D2 (and power hub connected to a 12V 7.5A power supply) to Windows 11.

Software Description

I want to understand what the motor does exactly when I enable the torque in dynamixel wizard 2.0 in current control mode.
According to the manual, the motor should turn on the torque and lock EEPROM Area parameters, but I think that the motor is doing something more that I don’t understand, and I would like to disable it.

Issue Description

If the torque enable is off, and I turn the motor horn, it moves freely but when I enable the torque (without setting a goal current or any other parameter) the motor continue to stay stationary but become to be more difficult to turn by hand (the force required is higher), it is like the motor introduce an extra friction that make more difficult to turn the horn and generate more back current/voltage.

What is it happening? How can I change this behaviour?

The Torque Enable setting toggles the supply of current to the motor on and off.

The difference in behavior you are reporting is because when the torque is off the motor is completely de-energized, and is not adding any resistance to backdriving. Once the torque is enabled the motor is actively adding backdriving resistance.

Using Current Based Control mode can allow you to adjust the amount of compliance when torque has been enabled, but this general behavior is intended operation and cannot be disabled.