[Paparazzi-devel] 127 ways to reverse a servo

[Martin P]

Hi, 

I am still ground testing only. 
I was happy to see that my ailerons moved in the correct direction in manual 
mode. 
When the ailerons moved in the wrong direction in AUTO1, I changed the sign of 
ROLL_ATTITUDE_GAIN from negative to positive and saw that the ailerons moved 
correctly when I rolled the aircraft left and right. All right, but then I 
started the simulator and the plane went in a small circle. ROLL_ATTITUDE_GAIN 
back to negative, and it moved nicely in the simulator but wrong again in the 
real plane. 

Well, before venturing into the air, I would like to have everything correct. 
Even when I plan to do only AUTO1 flights, there is a chance that I lose the 
35MHz connection (interference, broken PPM wire,...) and fall into AUTO2. Then 
I would like the plane to fly and not to crash. 

What possibilities are there to reverse an axis? 

1) in the transmitter  
2) in the radio xml-file 
3) in the servos section 
4) in the RC commands 
5) in the command laws 
6) in the outer loop 
7) in the inner loop 

1) and 2) should be the same, but when I tried it with the throttle, it wasn't. 

2 to the power of 7 is 128, minus the setting you have, gives 127 ways to 
reverse a servo, probably 126 of them are wrong ... pretty confusing. 

Does the simulator tell it right or is there something to reverse as well? 
Are there laws to reduce the number of cases, let's say that ROLL_ATTITUDE_GAIN 
and COURSE_PGAIN should have the same sign? 

Greetings, Martin