This topic contains 3 replies, has 0 voices, and was last updated by peterpoon 3 years, 2 months ago.
I am playing with the torque control demonstration. The values of the actual torque are always positive. I don’t succeed to create a negative torque set-point (turning in the other direction).Although the set point is negative the actual torque stays at a ” constant” value and the shaft do not move
Is it normal ?
which exactly application are you running? It is not clear to me since the name of the topic App_demo_master_cyclic_position.
Still one comment, could it be that you are using a feedback sensor that is not Hall? The torque control in 2.0 version of software is working with HALL sensor only (which is extended for other sensors in the upcoming release).
I was using a modified master cyclic position demo where the setpoint of the position control is fixed. In this demo, position, velocity and torque are displayed on the console, with the data coming from the EtherCAT communication. At that time, I was using the hall sensors for feedback.
In this configuration, without any motion and no torque applied externally to the motor shaft, the displayed torque is not zero. Moreover, when I try to rotate manually the axis, I see an increase of the torque measurement but always with a positive increase, neither I try to rotate in one direction or the other. I was expecting a positive and negative torque value when changing the direction of the manual torque applied on the axis (reaction of the position controller).
Is is a normal behaviour from your knowledge of the software. What is the physical definition of the torque measurement ?
I would suggest you try the standalone app_demo_bldc_torque to see if it is working well for your setup.
When rotating manually the shaft you will see indeed only positive torque. It only has the proper sign when the torque controller generates a non-zero output. By default the torque value is a magnitude of the face currents. If you go to torque_ctrl_service.xc, you can comment out #define CURRENT_CONTROL to try a different method.
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