Hello,
I looked into using a MOSFET on a GPIO to disable the PWM feed until the
autopilot was fully booted; I hit a snag when I found the state of the GIPO
wasn’t all that well-defined during boot. An RC switch probably would have
worked though; should have thought of that.
At this point, I think I’ll go and try coding a new hard-coded case.
Not a great long-term solution, but it will address the immediate problem.
Thanks!
~Luke
Sent: Friday, May 20, 2011 6:58 PM
Subject: Re: [Paparazzi-devel] Preventing Servos from Cycling at
Boot
Hello, Is
there a possibility simply to put a small R/C or similar switch between the
servo and the TWOG that can be turned on after initialization and before flight?
Of course, more weight and complexity. Just a thought. -Stephen
Dwyer
On Fri, May 20, 2011 at 4:36 PM, antoine drouin <address@hidden>
wrote:
Hi Luke
On the twog, I believe
sw/airborne/arch/lpc21/servos_4017_hw.c is used.
On initialization, it
starts by settings all servo to 1.5ms
It has a couple hard coded special
cases when SERVO_MOTOR,
SERVO_MOTOR_LEFT, SERVO_MOTOR_RIGHT or
SERVO_HATCH is defined. It then
outputs the specific SERVO_MOTOR_NEUTRAL
etc... values.
On stm32 which
uses
./sw/airborne/firmwares/rotorcraft/actuators/arch/stm32/actuators_pwm_arch.c
,
the behaviour is different and I believe servos are not commanded
(no PWM
is output) until the autopilot runs and makes the first call
to
actuators_commit
I'm not sure what the right thing to do is, as
actuators are fed with
commands produced by the autopilot. There is
nevertheless a failsafe
value defined for those commands ( it is used on
failure of the
autopilot process - which only make sense on systems that
have a level
of protection between the autopilot and fbw processes). Maybe
a thing
to do would be to command servos using values computed from
the
failsafe commands, but that would mean those values would have to
be
computed before the actuators hardware
initialization.
hth
Poine
On Sat, May 21, 2011 at 12:11 AM, Luke Ionno < address@hidden> wrote: >
Question for everybody... > > I’ve got a TWOG-based airframe with
a servo-operated release mechanism; it’s > a little tricky to reset, and
unfortunately, at boot, all the servos cycle, > causing the release to
trigger. Is there any way to prevent the initial > servo
cycling? > > Thanks! > > ~Luke >
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