Re: [Paparazzi-devel] BL ESC

[address@hidden]

Any controller can be used, the exact PWM value that is sent to the controller 
for 0-100% throttle is completely configurable in the airframe file so all 
controllers are compatible and any controller will arm properly with or without 
the use of an R/C transmitter.  Upon each boot, the autopilot immediately sends 
whatever you have defined as 0% throttle (typically around 1200ms) and 
maintains that signal until a manual or autonomous command is given.  Most 
modern controllers are "auto calibrating" which is an undesirable feature for 
R/C pilots and even more so for autonomous systems but can be dealt with.  The 
calibration is done by defining the PWM value at boot to be 0% power and then 
defining some initial arbitrary mid-range value such as 1500ms to be 100% until 
a higher value is seen.  The net result of this behavior is that the motor is 
given full power at any command above 50% throttle until 100% throttle has 
actually been commanded at least once.  This is not an issue for planes that 
routinely take off at 100% throttle but can disrupt the throttle tuning and 
altitude control on any flights where 100% throttle has never been commanded.  
Castle Creations controllers can be configured for "fixed endpoints" which 
permanently sets the range to 1250-1850ms providing a consistent and 
predictable throttle response.
Throttle stick programming is also possible through the autopilot:  If the 
transmitter is on with the throttle at full or whatever is required for your 
ESC when the autopilot is first booted, the autopilot will immediately see the 
manual control signal and throttle position and pass that along to the ESC as 
the first value, triggering the programming mode.

Group,


  Permission to play dumb here but I do not have a lot of time to examine code, etc.  I would like to get an explanation as to what type of ESC is required to operate with the Tiny13.  There was mention that it cannot be a type with auto arming or similar.  High quality ESCs available domestically in my area have two distinct product lines, one being half the price of the other yet same current ratings but lacking half the luxury features including "throttle mode" which sounds suspicious.


Regards,
Matthew Currie
Nanaimo, BC Canada