I used V5+ as a flight controller, and the built-in compass was severely disturbed. I recently got a CUAV Nora, which uses RM3100 as a built-in compass. I want to test whether its anti-interference performance has really improved, and I also want to explore whether Permalloy can reduce a certain compass interference.
(Note : Because the continuous rain, I reverse the blades of the copter so that the copterwill not fly even if the throttle is pushed up. Therefore, the test is conducted on the ground. Please do not imitate my behavior at will. It is not verified by flight. Time-proven)
This is my copter, it is very beautiful ( hahaha )
This is its internal structure, very concise
This is how I installed the flight controller ( I forgot to take the picture on the test day. This picture is for your reference. I am too lazy to connect the wire again… )
My test standard is to observe the interference of the Compass Motir Calibration ,The official Ardupilot document recommends that it should not exceed 30% .
I used V5+ flight controller for the first test and did not do any shielding measures. It can be seen that when the throttle is about 43% , the current is 6A , and the interference is 93% . The second picture is a simple repeat test, which shows that my test is repeatable and reliable .
In the second test, I used the Nora flight controller, and did not do any shielding measures. It can be seen that when the throttle is about 55% , the current of the copter is 14A, and its max interference is about 24% (In normal circumstances, I should keep the throttle consistent, but the anti-interference performance of the RM3100 is so good that I I thought I got a wrong result, so I pushed the throttle higher)
Before the third test started, I disassembled the aircraft and used Permal to cover the switchboard to shield the magnetic field. Permalloy is a metal that can shield the magnetic field, so it will also shield the earth’s magnetic field. The correct way to use it is to use it to shield some of the larger interference sources from a certain distance. As long as it can reduce some of the interference, it has reached the goal. It is unrealistic to use it to shield all interference. When the area used by Permalloy is too large, the calibration will not pass, and the value of an axis may be very large. The installation method is similar to the picture below. I used a piece of paper for short circuit isolation caution! There is a risk of short-circuiting at random like this!
My third test still used V5+ flight controllers, but this time I used Permalloy shielded switchboards. When I push the throttle to about 50% , the current of the aircraft is about 10A , and the maximum interference is 55%.
In the fourth test, I replaced the V5+ flight controller with Nora , and used a permalloy shielded power distribution board. When I push the throttle to 50% , the current is 11A , and the maximum interference is 10% ! What a great test result
I used a table to summarize this test.
As can be seen from the table, the interference ratio of the switchboard in my plane is very large, but because my rigorous testing, I cannot get a specific ratio. Another use of RM3100 is Nora , its built-in compass great resistance to interference. Because when V5+ under 43% throttle, the interference has reached 93% , while Nora is under 55% throttle, the max interference is only 24% !