In part 1 of this article we installed Mission Planner on our desktop or laptop and used it to load the firmware for our vehicle into our Pixhawk.

The next step is to configure and calibrate your Pixhawk.



Plug the USB cable into your Pixhawk. (Note: the USB sockets on all these flight controllers are not very durable. Be careful when you plug in a USB cable. It is not uncommon to push the socket off the board and ruin your flight controller if you push too hard.)



With Mission Planner up and at the opening screen, go to the upper right and choose your com port and set the baudrate to 115,200. Then click on connect. Mission Planner will query the flight controller and make a connection. Then it will download all the settings of the Pixhawk so that you can view or change them. The information in the heads-up-display (HUD) on the upper left will not be valid until Mission Planner finishes connecting. But when it does finish you will see the HUD change as you carefully pick up your flight controller and tilt it. Note that the artificial horizon will tilt the opposite way to the way you tilt the flight controller. This is the way it should work. In the box below the HUD you will see the numeric values of the sensors changing as you move the flight controller.

...Continue Reading

Ardupilot and Pixhawk, hands down, have the best features per dollar than any other flight controller. That is, if you are doing work and not racing. But with that extensive set of features comes complexity. The key is learning only what you need to get started in order to not get overwhelmed at first. Then, add new features as you need them.

Let's take a look at the system and what it entails.



First, you have your flight controller. It will be a Pixhawk or one of the derivations of the original Pixhawk designed by Lorenz Meier of the Swiss Federal Technical Institute of Technology as a graduate student project (www.pixhawk.org). This board is basically a computer chip with memory to store values and sensors to figure out where it is located and how it is moving. The flight controller computer requires software to teach it how to do its job. This program is called Arducopter, or Arduplane etc., and it is firmware that you load onto the flight controller. There are two different versions of firmware for the Pixhawk. It is a little confusing. The hardware previous to the Pixhawk was called the PX4. This board was in two pieces with the i/o on a separate board but newer versions integrated both boards into one like the Pixhawk did. When the Pixhawk, an improved version of the PX4, was released and funding support provided by 3DR the progress of features and improvements moved rapidly with the Pixhawk and the PX4 was left behind. The license for using the Pixhawk design...Continue Reading

***** Note: I am a copter guy and this article is about how Arducopter is setup.
***** Arduplane , Ardurover, Ardusub etc. are similar but not exactly the same.
***** The information in this article applies to the Pixhawk, not the APM flight controller.
***** See my older article "Controlling external devices with an APM"
***** for information about the APM. Some of the parameter names have changed since
***** Arducopter 3.3.3 so they may not match what you have used previously.
************************************************** ******************************************

LED Lights, Spot Lights, Grippers, Retracts, Cameras, Gimbals
There are many external devices you may want to control remotely from your radio or automatically during a mission with Pixhawk.

The first thing to consider is what kind of signal controls your device? Does your device require a simple on-off switch to turn it on and off or activate it? Or, does it respond to a PWM signal like your RC Transmitter puts out? A PWM signal is a series of pulses that represent numbers. A device that is controlled by a PWM signal can decode the number, like your throttle does, to determine not just an on-off but a continuously changing value. PWM devices are much more complicated than simple on-off devices. You can get simple LEDs that just require a voltage to turn them on or more complicated LEDs that use a PWM signal to control colors and moving patterns, etc. The simple on-off control is called &...Continue Reading

One of the most critical components of a successful build is getting the motors to spin in the right directions on the right arms and getting the right props on the right motors. Using the motor order pictures is the first step. The images show the different aircraft configurations, like quad, hex, octo etc. and they illustrate what arms should have motors that spin in what directions. These drawings are viewed looking straight down on the top of the multicopter. Remember that with a Coaxial multirotor the bottom motors are mounted upside down but the drawing shows the spin direction as looking down from the top, so the bottom motors have to be setup so they spin correctly even tho they are mounted upside down and the top side of the props must be up. Hence the props are mounted the opposite side up than the top motors so all props have top side pointing up.

IN Arducopter 3.5 and later there is a new Frame_class and Frame_type parameter that you must set. Class is a hex, quad or octo and Type is an X, H or Plus which specifies the orientation of the frame.

The difference between an X configuration and a H configuration is that the H rotates the motors around one position to help Yaw control on H frames that have a long center boom with arms that tend to twist around that center boom under heavy load. If you have quad that looks like an H but has a stiff box like center or other design which does not tend to twist under load then use the X configuration.

Here are the...Continue Reading

One of the most important safety features of the Pixhawk is the Return to Launch or RTL. This feature will cause the multirotor to fly back to its home point due to a number of "triggers" or alarms that will cause the action. There are a number of fail-safe parameters in Arducopter that can be set such that if the threshold is met they will trigger a RTL event. For example, if your battery voltage drops below the level you set, if the ground station link is lost, if your transmitter link is lost, etc.

These events will trigger a RTL. The multirotor will fly back to the home point and hover or land. The key here is that RTL is a GPS- dependent mode. You must have a good quality GPS lock. One of the problems with multirotor GPS is that most only give an indication that they have or don't have a 3D lock on the satellites. But a 3D lock is just a minimum reception of the satellite signals to determine your location. Ardupilot wants you to have more than a simple GPS lock and that means 8 satellites and a good quality reception of the signals. That is why I think the new status display code being incorporated into the next versions of Ardupilot are so important. The little OLED display will tell you if you have a GPS lock, with how many satellites, and the quality of the signal. This is valuable information for an aircraft that depends so much on GPS navigation.

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When the flight controller is triggered to RTL...Continue Reading