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Re: [Paparazzi-devel] Lisa/L Servos
From: |
Andreas Gaeb |
Subject: |
Re: [Paparazzi-devel] Lisa/L Servos |
Date: |
Mon, 22 Nov 2010 10:52:56 +0100 |
User-agent: |
Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.2.12) Gecko/20101027 Lightning/1.0b2 Thunderbird/3.1.6 |
Hi Poine,
Am 19.11.2010 14:48, schrieb antoine drouin:
> Hi Andreas
>
> You're correct, lisa/L is designed to drive 6 servos directly. All
> pins of the 64 pins STM32 are used.
so the PPM input is not on the CON_SERVOS_2 connector, though it is
named RC_PPM on the schematic? What pin do you connect the receiver to?
> If you're not using some
> peripherals ( like I2C1, which is commonly used to talk to the I2C
> motor controllers on quadrotors) I could write code to use those pins
> to drive two more servos ( this is how I designed lisa/M, 6 servos and
> I2C1 or 8 servos ).
I'll probably need one I2C for sensors. Is I2C2 used by default?
> [...] Also you may not be able to supply them from the internal
> power supply of lisa/L ( there's one dedicated power supply for servos
> and USB but it's only good for 2 amps).
The servos will definitely need their own power, as even the motor BECs
cannot provide enough current for eight metal gear servos.
> The solution that I would advise in a big vehicle is to use a servo
> driver and a dedicated power supply ( BEC) located close to groups of
> servos.
I had already thought about using an Atmega or PIC based I2C to PWM
converter, there are some on the internet.
> The connection between the autopilot ( lisa/L) and the servo
> driver would be CAN which is a differential signal designed to travel
> long distances and be immune to electrical perturbations.
Do you know if CAN is better in this case than I2C?
> The CSC board (Can Servo Controller) could be used for that (
> http://www.poinix.org/images/csc_1_0.jpg )
is this what the sw/airborne/csc software and misc/csc hardware is
about? Is there any documentation on this?
> An even better solution would be to use a lisa/M (
> http://paparazzi.enac.fr/wiki_images/Lisa_m_top_small.png )
Is there already more information about this than on the Lisa wiki page?
> You could have for example one servo driver in each wing of your
> vehicle ( and maybe another one in the tail ). The electrical
> connection would be only two wires for CAN and two wires for power.
Ailerons, flaps and motor controllers are no more than 60 cm away. I
think I'll to drive these directly from Lisa and see about the jitter.
The tail is farther, so I'd rather put an extra controller there.
>
> HTH
It does.
Thank you very much,
Andreas
- [Paparazzi-devel] Lisa/L Servos, Andreas Gaeb, 2010/11/19
- Re: [Paparazzi-devel] Lisa/L Servos, antoine drouin, 2010/11/19
- [Paparazzi-devel] Booz, Cédric Marzer, 2010/11/19
- Re: [Paparazzi-devel] Lisa/L Servos, Famille Chateauvieux-Hellwig, 2010/11/19
- Re: [Paparazzi-devel] Lisa/L Servos,
Andreas Gaeb <=
- Re: [Paparazzi-devel] Lisa/L Servos, antoine drouin, 2010/11/22
- Re: [Paparazzi-devel] Lisa/L Servos, Rui Costa, 2010/11/23
- Re: [Paparazzi-devel] Lisa/L Servos, Gareth Roberts, 2010/11/23
- Re: [Paparazzi-devel] Lisa/L Servos, Andreas Gaeb, 2010/11/24
- Re: [Paparazzi-devel] Lisa/L Servos, antoine drouin, 2010/11/24