manage motor acceleration

Thread Starter

CStreb777

Joined Jun 23, 2021
11
How do i manage acceleration, when someone is moving the device slowly i want to be sure the motor response slowly?

As they get more aggressive by moving faster, I want to move faster. but I do not want sudden jumps in acceleration for any reason.
smooth and responsive is what i am looking for.

Thank you.

The belt is moving up and down my the users hand pressure
 

mcardoso

Joined May 19, 2020
198
So I guess the most basic question is what kind of motor are you using? Is it a DC brushed or an AC 3 phase? How are you controlling the motor? Is there a drive?

Second, what is the process you are responding to? You reference "someone moving the device" but don't describe what the device is, what on the device you are measuring and expect the motor to respond to. What is the intended response?

With those questions answered, we can start to get a picture of the device, the interaction between the process measurement and the action of the motor, and finally we can decide on how to manage the motor acceleration. Perhaps that needs to be a limit applied to the control signal going to the motor driver, or perhaps the drive itself can limit the motor acceleration.
 

Papabravo

Joined Feb 24, 2006
17,297
Angular acceleration and deceleration require torque. Generally speaking motor torque is proportional to current delivered to the winding(s). The details are different for each motor type, but controlling the delivery of current to an inductive load is the crux of the drive problem. Measuring angular velocity, acceleration, and jerk(1st time derivative of acceleration) is the other half of the solution.
 

Thread Starter

CStreb777

Joined Jun 23, 2021
11
Well, my system is motor lifting a load over a loadcell. i can go up or down with load. i find that in current mode using a pmac motor cogs at low speed and has huge hysteresis issues with load and temperature. if i go to velocity mode I get great control until I contact the ground. then is jumps up. I believe the loadcell is responding slow 100 hz via canbus . if i sense a loss in weight I know the user is lifting the load. If load gets heavier, I know the user is pushing down. I am thinking my control loop speed is way to slow. I think servos have better resolution and can operate at 2500hz. I have not verified, but this is the direction I am going.
thank you in advance for your advice

i know the load weight and try to match the loadcell to the weight value using a closed loop
 
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