Soft start/stop and position control

Questions about using encoders with the Roboclaw product line
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Joe
Posts: 34
Joined: Fri Dec 23, 2016 1:00 am
Soft start/stop and position control

Post by Joe »

Hi I just have ordered a roboclaw 2x42ST but delivery is delayed. So I'm reading the manual and the forum threads. It's very confusing for me as a novice without ever having used the device and the software ;)

One thing I want to do is to move a 100lbs device to certain positions. To do this in a proper way I need a soft start and stop of the motor. Is there a feature with roboclaw which supports this or how can this be done with the code/commands?

Thanks for your help.
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Basicmicro Support
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Joined: Thu Feb 26, 2015 9:45 pm
Re: Soft start/stop and position control

Post by Basicmicro Support »

How are you planning on controlling the controller? RC Mode, Analog or Packet Serial? Are you planning on using an encoder on the motor to turn it into a big servo or is this going to be an open loop?

If you will be using an encoder and using the motor like a servo you will use the position commands(after properly tuning the settings for position control). These commands let you specify a speed acceleration decceleration and position to move to.

If you will be using an open loop system(eg no encoder) then you can use the Duty commands with Acceleration control. These will ramp the power to the motor(up or down depending on the command and whatever the current Duty value for the motor is).

If you are going to use Rc or Analog mode you can set a default acceleration value to allow smooth control using an RC controller or analog pot/joystick.
Joe
Posts: 34
Joined: Fri Dec 23, 2016 1:00 am
Re: Soft start/stop and position control

Post by Joe »

Hi, I will have two encoders and work with position commands.
I think I will come back to the forum and discuss this when I received the roboclaw :-)
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Basicmicro Support
Posts: 1594
Joined: Thu Feb 26, 2015 9:45 pm
Re: Soft start/stop and position control

Post by Basicmicro Support »

Ok, just continue from this post when you are ready.

One note, if you plan on using quadrature encoders with position control you need to home the encoders(eg reset them to a known position. Since these are incremental encoder they dont remember their last position after powering down and dont know what position they may be moved to when powered off.

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