Pixhawk 2 or 3 Pro?


#1

ello everyone,

For a business project, I hesitate between the Pixhawk 2 & 3 Pro. Which one is the most reliable and why?
What do you think of the RTK module on a Pixhawk? Is it fairly reliable and easy to install?

Thank you in advance.

Best regards.

Etienne


#2

Hello,

My approach might be biased but essentially Pixhawk 3 Pro is a new design with new features, Pixhawk 2 has exactly the same design as Pixhawk 1, but it has more flight hours.

U-blox modules work relatively well, and are fairly easy to install. It is plug-and-play with QGroundControl.


#3

@Kevin can you explain the new design and features ?

From what I see is both inherit from the Pixhawk 1 with a little more ram and isolated Imu. Pixhawk 2 (or the Cube) has the same features plus 3 IMU and thermal regulation and a smaller design.

Another point of consideration : The cube is only supported by Ardupilot (PX4 status is unknown) and Pixhawk 3 pro by PX4 (Ardupilot port is on-going)


#4

You’re quite incorrect about the assertion that PH2 is the “same design as PH1”, while suggesting PH3 is “new and improved”.

Can you please list the similarities between PH2 and PH1, while simultaneously showing how PH3 implements that design feature differently?

I think a rigorous examination of the facts will show that the PH2 is quite a bit closer in design to the PH3 than it is the PH1. But then with a few features added which PH3 doesn’t even have. (3rd IMU, IMU heating, etc.)

Kevin, as somebody who is unbiased, I buy hardware from several vendors depending one which is most suitable for my needs (including Drotek), I find this comment from you disappointing.


#5

@khancyr @Robert_Lefebvre

I apologize for the brief answer and will try to provide you with more details :

  • Processor speed : this new processor runs at 180 MHz instead of 168 MHz, this has been possible thanks to a different set of PLLs that make it possible to have a dedicated clock for USB and SD card. It may seem trivial but it implies lots of changes at OS level. As a result, not only can the board execute instructions faster, but for instance SPI buses can run faster as well. In NuttX, the SPI speed you select on software is not the speed you get on hardware, mainly because SPI clock is derived from bus clock and then “hardware-divided”.
  • more RAM : seems trivial but lets you load more drivers and have more CPU
    -intensive code, will become progressively more and more useful
  • Flash memory : same as F427 Rev.3, 1MB more than PH1
  • Form factor : very similar to PH1, PH2 is smaller without carrier board, bigger otherwise (most users have the carrier board)
  • Manufacturer availability : this has been a recurrent problem with previous versions, something that we will definitely try to improve and solve
  • Power supply : in PH3, servo rail is completely independant from the rest of the board. Being able to power the board from servos caused more problems than it solved. Now the idea is to have two redundant power supplies with dynamic switching and notification to the user.
  • Schematic : removal of a high number of unadapted components, reduces the risk of failure
  • Sensors : we have had problems with the LSM sensor in the past, so we switched to MPU9250 and ICM20602 (the former is positioned by Invensense as a successor of the latter in terms of quality)
  • Sensors 2 : we will provide an option for having an internal 3rd IMU, a 2nd MPU9250
  • Lots of I/Os for development : 2 I2C, 2 SPI, 2 CAN
  • Ports : dedicated port for ESP8266 (Wifi) and dedicated debug ports for developers
  • OEM : version coming, for integration on carrier board with companion computer or custom PCB
  • Vibration damping : hours of bench tests to select the most adapted foam, but lack data to compare to PH2
  • Heating : several factors let us think the IMU heater is not essential, such as : sensor temperature inside the foam, software temperature calibration across a range of temperature
  • Software support : I think PH2 is fully supported in PX4 now. PH3 is fully supported in PX4 and validation-pending in Ardupilot

This has been a lot of serious work, and we still have in mind to endeavour to improve it. I hope to have answered your questions, please feel free to post your comments/ideas/improvements.


#6

I know this original post was over a year ago, but did anything ever come of this comment? I don’t see anything online. Is there a version out there that has integration with custom carrier boards?