Linear actuator torque control
The positioning control (real industrial stuf) is done in cascade with multiple controllers: Position controller (P-regulator), Speed controller (PI-regulator), current controller (PI-regulator).
https://www.google.si/search?q=position+control+loop&amp;biw=1391&amp;bih=683&amp;tbm=isch&amp;tbo=u&amp;source=univ&amp;sa=X&amp;ved=0ahUKEwj0gMXLo-rJAhWDfxoKHaUmCTMQsAQIIA#imgrc=N1aiYN6Li7XBCM%3A
When you ommit certain stages, the control gets worse. For example if you don't have current transducer, you can control the motor directly from speed controller, that would be voltage control. If the load wants to move the motor at standstill, the PI regulator "will find" such voltage that, will feed such current into the motor, that will produce such torque at shaft, that will put the motor back to standstill.
If you have a current transducer, then you can make two PI-regultors. First is speed control which gives the setpoint to second one PI-reg. the current controller. Now the output of current controller has to control PWM and measures a current feedback with the current transducer. With extra current feedback the overall dynamics will be faster compared to previous method without transducer.
So the rough conclusion is: the torque control is actualy the current control of the motor.