[Dprglist] First BBR implementation and some questions

[Thalanayar Muthukumar]

Wow - 1 ms.
And this work was done in 2009 …
hizook.com web site is no longer available. Wonder how this technology may have evolved over the years.

Regards.
- Kumar

Sent from my iPhone

> On Oct 31, 2021, at 5:52 PM, Karim Virani <pondersome64 at gmail.com> wrote:
> 
> 
> Many of y'all will remember this super-speed finger bot - 1ms loop time or shorter:
> https://www.youtube.com/watch?v=-KxjVlaLBmk&ab_channel=Hizook
>  
> 
> 
>> On Sun, Oct 31, 2021 at 5:42 PM Karim Virani <pondersome64 at gmail.com> wrote:
>> 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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