Aquaticus ROV

Homebuilt underwater robot
 
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Motor Controller

Features

  1. Controls max 3 DC motors
  2. Current up to 4A/motor
  3. Supply voltage up to 46V
  4. Current sensing
  5. PWM control
  6. Single sided PCB
  7. 15 pin Control Unit compatible header

Applications

Designed to control thrusters.

Schematic

The circuit consists of three L298 ICs. Each IC controls one DC motor.

Motor Controller schematicMotor Controller schematic

PCB

Single sided, size 100x86mm.

Motor Controller PCBMotor Controller PCB

An old version of motor controller: Thanks to nasty bug in elements library this PCB was incorrectly designed. It never worked properly.An old version of motor controller: Thanks to nasty bug in elements library this PCB was incorrectly designed. It never worked properly.

Note

This is preliminary (not tested) design! Full description and PCB artwork will be published after tests.



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Not sure if this will work
Submitted by Anonymous on Sat, 2008-03-29 05:52.

I'm not certain that this will work the way you intend with the current schematic.

Assuming you are using the DIRx lines to determine the motor direction (eg. H = Forward, L = Reverse).

According to the L298 datasheet (table on p16), If you drive the PWM into one input and DIRx into the other, when In1 and In2 are different, the motor will drive correctly, but when they are the same, you have "Fast Motor Stop" mode.

I think what you want to do is drive Ven with the PWM input (ie. use "Enable Switching", rather than "Input Switching", DIRx goes to In1 and In4, and Inverted DIRx goes to In2 & In3 (you will need to add an inverter IC).


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RE: Not sure if this will work
Submitted by admin on Mon, 2008-03-31 09:35.

It was assumed you generate PWM on PWMx line or DIRx lines depending on rotation direction.
You're right how L298 works but your assumptions are incorrect (DIRx/PWMx pin names are used to fit Control Unit pins).


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