When I first tried to launch this robot, I've set the full speed to have a good show.
But I've noticed that the front had been raised significantly at full thrust.
If my robots front is raised each attack state, he's dead from the start.

It needs a Soft Start, maximum acceleration allowed to drive the platform.

Recently I've been playing to solve that problem.
Robot has tactile surface sensors - micro switches, which deactivate if the front is raised.

With the help of MegunoLink Tool, Analog reading, Serial communication and code adjustment, we can make an experiment. The Report is bellow.

My course project asks for 20:1 speed regulation range, so speed is 5% steps discrete.
A delay between steps is adjusted.

Adjustment results:
  • Full thrust: No Soft Start applied, as you already noticed that the front has raised, Switch1 readings shows that 0 value, which is OFF. 270ms flying.
  • 1 ms between steps: Not enough yet, 237ms flying.
  • 2ms between steps: 220ms flying blade.
  • 3 ms between steps: 193ms flying blade
  • 4 ms between steps: 159ms max flying blade, unstable yet.
  • 5ms between steps: Eureka the Golden middle! No flying blades.
It might be better to add a millisecond as 20% more in reserve, because the dead zone for switches is 2mm (~0.1") between flying blade and surface. Rate of voltage change should be 92.5~111 V/s, provides a Soft Start for motors.

Update 2013.01.03: Another more accurate way to find out if the blade is being raised:
  1. Place a sheet of standard A4 paper on the surface of Dohyo in front of the vehicle;
  2. Soft start it to full speed;
  3. Do it several times;
  4. If the blade gets on top of the paper, that means it is still being raised, add a millisecond or two between 5% PWM duty cycle steps.
  5. If the paper is being pushed only, configuration is over and you're good to go.

No comments:

Post a Comment