Tuning servo motor to withstand external force of another servo motor

[ilnus]

Hi,

I have two brushless DC servo motors connected to their own third-party amplifier operating in torque mode. These motors control a reel-to-reel system, where a metal ribbon travels from one reel to the other. One amplifier is connected to the NI 9516, where I am using Softmotion to control its velocity. The other amplifier is set at a constant torque to take up the ribbon.

The problem I am having is with tuning the velocity-controlled motor to withstand the torque caused by the take-up motor. I need the motor to operate at a constant velocity while able to withstand the forces cause by the pull of the other motor. So far I have been unsuccessful at tuning it to counteract that external force. I was hoping to have Softmotion control the motor's velocity while the motor itself is set in torque mode, but it seems I have to set the motor to velocity mode to solve my problem. Is that the only answer, or is there another way?

Linus

[WearWolf]

Hello Linus,

I see that you currently have an open service request on this issue with one of our Applications Engineers. We will consolidate this issue to the service request and I will post the final answer here after a resolution has been found.

[ilnus]

Just to let you know, I already solved the problem. It seems that my initial settings for the servo amplifier was incorrect, and that I was providing too little power to the motor. It was set to a low power because it was making a noise when it was set to a normal value. I learned eventually that the source of the noise was not because of the power, but because the initial gain tuning parameters were not set correctly. When I changed the tuning parameters, I was able to supply more power to the motors, which gave it enough torque to withstand external forces. I initially used the gain tuning values recommended by the Getting Started the AKD EtherCat Drives guide, even though I was not using the same brand of motor. I though the suggested uning parameters would apply to my brushless servo motor, but it turns out that's not the case.