[Dprglist] First BBR implementation and some questions

[Karim Virani]

The loop time is entirely up to you. The question is, how quickly does your
robot need to react? That depends a lot on physics - on scale. It also
depends on the needs of the most timing-sensitive (non-ISR) sensors you are
managing, and how you service them.

We don't even have a set loop time since we are using Android on most of
our robots. Our loop time varies a lot, but is generally under 50ms. We
normalize all our timing to seconds and our math looks like normal physics
calculations vs. something short-cutted to a fixed timing loop. Granted,
this is not a common approach in microcontroller-driven hobbyist robotics.
Deemed wasteful of processing cycles by many.

On Sun, Oct 31, 2021 at 5:31 PM Thalanayar Muthukumar <tnkumar at gmail.com>
wrote:

> Makes sense Karim, that at all times, the robot is interruptible by higher
> priority events.
>
> Is 50ms ok? Or is 20ms desirable?
>
> Regards.
> - Kumar
>
> Sent from my iPhone
>
> On Oct 31, 2021, at 5:26 PM, Karim Virani <pondersome64 at gmail.com> wrote:
>
> 
> I agree with Doug, you should never have blocking code unless you can
> dedicate a separate thread to it apart from your main loop's thread.
>
> And not to start up the whole debate again, I personally vote that there
> is no use for ballistic behaviors. I treat them as an academic construct.
> There are plenty of uses of objective-oriented and terminating behaviors -
> including those where the objective is to last for a certain amount of
> time. But they should still be interruptible and cancellable by higher
> priority behaviors.
>
> On Sun, Oct 31, 2021 at 5:08 PM Doug Paradis via DPRGlist <
> dprglist at lists.dprg.org> wrote:
>
>> Kumar,
>>     I always pass through the loop. So a 1 sec backwards maneuver would
>> use a loop counter with a disengage value of 50 for a loop time of 20 mS. I
>> am not using a multitasking framework, which opens up other possibilities.
>>
>> Regards
>> Doug P.
>>
>> Sent from my iPhone
>>
>> On Oct 31, 2021, at 4:54 PM, Thalanayar Muthukumar via DPRGlist <
>> dprglist at lists.dprg.org> wrote:
>>
>> 
>> https://youtu.be/fuFamNWyXc4 (~15 sec)
>>
>> 20 times per sec
>> - default behavior - go straight forward, green headlights
>> - higher priority behavior - light sensed, turn left, red headlights
>>
>> My understanding of BBR is that there should be no state maintained.
>>
>> Question - If we trigger a ballistic behavior (e.g. go straight backward
>> for one sec), is it ok to not return to the loop every 50 msec?
>>
>> Or is it preferable to maintain state and count 20 times for getting
>> duration of 1 sec?
>>
>> Regards.
>> - Kumar
>>
>>
>>
>> Sent from my iPhone
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