Re: [Paparazzi-devel] Maximize climb rate after take-off

[pascal . brisset]

There is an example of ground speed control loop in nav.c 
(nav_ground_speed_loop, line 208).
It controls the throttle and has been tested in simulation only.

You can write a new loop (in a module) to control the pitch (the my_pitch 
variable) and run something close to

<attitude vmode="throttle" throttle="1" pitch="my_pitch" /... >

Ask if you need help

--Pascal



----- Original Message -----
From: "Steven Wawryk" <address@hidden>
To: address@hidden
Sent: Monday, 11 May, 2009 08:24:53 GMT +01:00 Amsterdam / Berlin / Bern / Rome 
/ Stockholm / Vienna
Subject: Re: [Paparazzi-devel] Maximize climb rate after take-off


Hi Pascal,

For example, the MicroPilot autopilot allows the use the following alternatives:

* airspeed from throttle and altitude from pitch

* altitude from throttle and airspeed from pitch

depending on which of altitude or airspeed is to be most tightly controlled in 
the current mode.

In my case, throttle is set to max to increase altitude as quickly as possible.

Cheers,
Steve


address@hidden wrote:
> Hi,
> 
> If you don't set nor a climb rate (vmode=climb) neither an altitude 
> (vmode=alt), what do you want to control with pitch=auto ?
> 
> --Pascal
> 
> 
> ----- Original Message -----
> From: "Steven Wawryk" <address@hidden>
> To: address@hidden
> Sent: Monday, 11 May, 2009 04:19:36 GMT +01:00 Amsterdam / Berlin / Bern / 
> Rome / Stockholm / Vienna
> Subject: [Paparazzi-devel] Maximize climb rate after take-off
> 
> 
> Hello,
> 
> I'm working with David Bryant on the compressed air cannon launched system.
> 
> What I would like to be able to do in the flight plan is to go into a maximum 
> climb rate mode straight after launch until a given altitude is achieved.
> 
> What I'd like to be able to do is something like:
> 
> <attitude roll="0.0" pitch="auto" throttle="1.0" vmode="throttle" 
> until="estimator_z >= ground_alt+security_height"/>
> 
> the aim being to use pitch control at maximum throttle to achieve a given 
> airspeed set-point.
> 
> I'd rather not have to set the pitch or climb rate because then I'm just 
> guessing what airspeed it will go at.  Too low and it will stall, too high 
> and 
> the higher drag means it won't climb as fast as it could.
> 
> The problem is that the flight plan build doesn't allow auto-pitch with 
> throttle 
> vmode.
> 
> The other vmodes don't seem appropriate, and with the default alt vmode, the 
> build also fails because an alt attribute is needed.
> 
> If I set the alt attribute, I'm not sure how it will behave.
> 
> Is there a reason for prohibiting auto-pitch with throttle vmode?
> 
> Does anyone have any other ideas?
> 
> Thanks,
> Steve
> 
> 
> 
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> 
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