PBP projects for R/C models

[Kenjones1935]

Take a look at:



Please tell me what you think.

Ken

[cncmachineguy]

Ken that is just stunning!!!!!

Please share with us the change that made it happen, or was it multiple changes? Looks like now you can tweek the distances to get closer to the wall.

[mackrackit]

COOL!!!!
What did you do??

[Kenjones1935]

The changes were of two types.

1. Instead of "braking" by turning off the DC voltage to the wheels (thereby relying on reverse polarity created by the rolling momentum of the wheels in the DC motor) I now use the DPDT relays to reverse the polarity for a few hundred milliseconds.

2. I put some PAUSE commands in to make sure wheel and steering related commands had time to actually do what I had expected.

Thanks...

Ken

[Kenjones1935]

I put the car up on blocks and found that when going forward it only turned left in my patented incremental way. It also flashed the SONARs at about 1/2 the usual rate.

The Vcc wire for the right side SONAR had become disconnected.

Soooo with the front SONAR working and the right SONAR always saying zero distance to the wall, the car turns left in little bits except when it approaches a wall head on. Then it brakes and swerves left.

That's exactly what my video shows.

Given that information, what if anything should I fix?

Ken

[mackrackit]

Well now you know exactly where the problem is. Connect the side scan and start tweaking that part of the code.

[Kenjones1935]

The issue is controlling the steering. It is bang-bang but I can modify the length of time and the frequency of each 'bang'. The plastic wheels slide easily. This is true of turning as well as forward or reverse drive.

I hope not to introduce an adjustment POT. It appears that the plastic mechanical parts are not consistent. Kicking the steering wheels back from full reach seems not to be symmetric. Hmmmm.

Ken

[Kenjones1935]

The car turns left when the right SONAR says it is further away from the wall than "desiredtrack". The car then moves a bit more as it rotates (turning right) its distance to the wall increases as a function of its rotation.

So it decides to keep turning right. Wrong!!

I need to think more about this.

Ken

[malc-c]

Take a look at:



Please tell me what you think.

Ken

Ken,

Not been following this thread for a while, but simply based on that video my guess is that due to the wheels having limited grip it slides / wheelspins each time the controller nakes an adjustment. If you are able to change the tires for something that grips better you might find it has better control of it's destiny