Managing high inertia loads

5 years 3 weeks ago #29531176 by davidk
From the beginning, I want to say this topic isn't about a controller issue. It seems I don't fully understand some basic theory about using regulators and high inertia loads and I think you can help me.

So, I have a carriage on tracks. It weights 60kg and has 8 wheels, two are motorized and one has an optical encoder on it.
I have two DC motors rated at 5000rpm 150W but I use them for maximum 2000rpm so their output power would be lower. I have a SDC2130 controller and a remote controller with a joystick for manual jog and interface for storing some

I need it to go and stop to a precise position, so I use counter position feedback loop

The problem is, any PID setting I use, it will bounce around the desired position. I tried to lower accel and deccel to very low limits and it moves somewhat smoothly, but these accelerations are way much slower than I can manually do with a joystick. I know there has to be a match between system inertia and control system and I wonder if motors are too weak. Are there easier methods than doctoral thesis to find if I sized motors correctly?

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4 years 10 months ago #29531391 by Andrew20
We have done 132KW motors on star/delta starters using klockner moller contactors so 5.5 KW is a little on the low end .

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4 years 10 months ago #29531393 by davidk
Replied by davidk on topic Managing high inertia loads
It would be useful to have two cascaded PIDs for speed and position for precise position control.

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4 years 10 months ago #29531394 by roboteq
Replied by roboteq on topic Managing high inertia loads
Try using the Closed Loop Position Relative mode, or the Position Count mode.

In this mode you can define the acceleration, max speed and deceleration in order to smoothly reach your destination point. Look at the manual for a detailed description.

This technique will work well but it implies that you will "take your time" to do your motion.

If you want to go as fast as possible, then the other approach that you can try is to look at the counter continuously, and send a stop command at the right time to reach the end point

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