[islandlabs] Have RC transmitter and receiver

Jim Marinis jmarinis
Mon May 6 14:56:49 EDT 2013


I'm looking into changing the number of samples per update.  I've seen 
references to the ADXL345 being sampled at a rate of 100hz, so I'll need 
to do a little investigating to see what we can actually get.

- Jim

On 5/6/2013 2:33 PM, Burns, William wrote:
> Futaba "Skysport" 6H FP-6VH
> 6 channel 4 servo
> FM Digital Proportional Radio Control System
>
> ----
>
> FYI:
> Basics of PID control:
> 3 terms:
> 1) Proportional
> 2) Integral
> 3) Derivative
>
> What we have now is Proportional. The further the copter is from "true", the more power the copter applies to correcting that.
>
> note: The "Integral" and "Derivative" terms refer to the mathematical operations.
> (ignoring that for now)
>
> The integral term compensates for "long term" difficulties w/ a proportional response.
> example: If the center of gravity of the copter is mismatched/offset from the center of thrust, the copter will list to one side until the proportional response balances that out.
> The copter will become "stable", but not be pointed straight up.
>
> The integral term "notices" that long-term tilt, and then compensates, effectively/gradually moving the derivative function's idea of where "up" is until the copter truly points upwards. (as-per accelerometer data)
>
> The derivative term is intended to reduce oscillations in the system.
> It takes the speed of rotation into effect, effectively acting as a "brake" if the copter is "turning" upright too quickly, and likely to overshoot it's target.
>
> The integral term is often not used in motor control applications. (if our center of mass isn't off, maybe we don't need it?)
>
> The derivative term is is often not used where there are random measurement errors because it then introduces erratic responses.
> Copter vibrations introduce these random errors...
>
> Filtering data may help remove these erratic error responses but... We're only getting 20 measurements per second?
> At that rate, averaging the last 5 measurements will get us a 1/8 to 1/4 second lag in our attitude/position reports.
>
> That lag may be too much and cause oscillations in the quadcopter attitude.
> It would be nice to be able to increase the data-rate from the accellerometer.
>
>
> -Bill
>
> http://www.power-eetimes.com/en/the-basics-of-doing-pid-design-part-1-classical-control-theory.html?cmp_id=71&news_id=222901382
>
> http://hyperphysics.phy-astr.gsu.edu/hbase/math/derint.html
>
> ________________________________________
> From: list-bounces at freeculture.org [list-bounces at freeculture.org] on behalf of Jim Marinis [jmarinis at mjmonline.com]
> Sent: Monday, May 06, 2013 1:43 PM
> To: list at freeculture.org
> Subject: Re: [islandlabs] Have RC transmitter and receiver
>
> Sounds like doing some real damage is in the not too distant future
> (your leg not withstanding).
>
> Which model of receiver/transmitter do you have?  I can take a look
> before Wednesday so perhaps we can give it a go.
>
> - Jim
>
> On 5/6/2013 9:21 AM, Burns, William wrote:
>> I Have an RC transmitter and receiver.
>>
>> It can control up to 6 servos.
>>
>> Not sure how to interface that to an arduino.
>>
>>
>>
>> Also: ...
>>
>>
>>
>> Quadshot: quadcopter/flying wing: transition robotics
>> http://www.youtube.com/watch?v=IK_-yTrwNtU
>>
>>
>>
>> Space Glider - FPV to Space and Back!
>> http://www.youtube.com/watch?v=rpBnurznFio
>>
>>
>>
>> Flite Test - FPV Space Glider
>> http://www.youtube.com/watch?v=DQMi6Jk38g0&t=3m20s
>>
>>
>>
>> How to Setup FPV w/ GoPro HD, HobbyKing 5.8GHz Transmitter/Receiver fo
>> http://www.youtube.com/watch?v=UKMQhWZtNRg
>>
>>
>>
>> FPV Ground Station - REVIEW
>> http://www.youtube.com/watch?v=RG76qShdKuU
>>
>>
>> _______________________________________________
>> List mailing list
>> List at freeculture.org
>> http://lists.freeculture.org/mailman/listinfo/list
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