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A project log for Smart leash

Simple navigation for pet robots

lion mclionheadlion mclionhead 11/25/2022 at 21:540 Comments

Debated whether to create a new truck board or hack into the debug header, the trick with the debug header is programming it requires plugging TX & RX into the UART dongle.  Using the leash requires wiring TX & GND to the UART dongle with RX & GND going to the leash.

Then there's overriding the autopilot.  The general idea is if the 900Mhz is on, it overrides the leash.  If the 900Mhz is off, it normally disables the motors.  Now the motors have to be enabled for another case.

The next problem is if the leash should send high level rate of turn & RPM commands or if it should send PWM to the servo & throttle.  The high level option has a lot less parameters.  There's steering center angle, steering proportion, starting distance, starting speed, speed proportion.

Made a doubler to bolt the leash on the container.  Made a very minimal cable which taps the debug output while allowing the leash to send to the debug input.  

The best steering algorithm ended up being direct leash angle to PWM.  The best throttle algorithm ended up being distance to high level RPM goals.

Overriding steering in any practical way with RF requires turning off the leash.  Throttle override just requires retracting the leash.

Noted the leash tends to get stuck full left when it gets caught up in its latch.  The latch has to be lowered when it's driving.

It now needs structural reinforcement to keep the wires from breaking, a wrist strap, a higher update rate.

Steering is accurate enough to keep it on a sidewalk with careful attention.  It could use a radius extension to improve steering accuracy.

It's not obvious in a video that it's self propelled.  It's actually a good idea since amerikans like to ban self propelled vehicles wherever they can.  

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