Recall that the car is a real 1/10 competition one. At the beginning I used the transmitter full throttle range (Futaba nominal), but since Guided and Auto modes didn’t work I had several small accidents (the car was uncontrollable), so I limited manually the maximum speed (SERVO2MAX=1580) at the controller (could be also limited at the transmitter or ESC). The ESC is calibrated to the full transmitter throttle range 1000-2000 (if I take the Pixhawk controller out (receiver to servo and ESC) I can race with the car).
1517µs (SERVO2_TRIM) is Futaba nominal neutral pulse width at the transmitter (moreless). It is the pulse width with which a traditional analog Futaba servo would be mechanically centered exactly.
The transmitter throttle stick has a 7:3 range (set mechanically), although the neutral mechanical point gives mid pulse width (1517µs). There is no backwards speed (no reverse speed admitted on these competition cars), so the whole lower range (first 3/10 of the total range) is used for braking.
So the transmitter is calibrated to give:
-1000 to 1517: the car brakes (possibly ESC shorts two phases). SERVO2_MIN to SERVO2_TRIM.
-1517: car stopped (SERVO2_TRIM=1517).
-1517 to 2000: car accelerates. While in this tests, the Pixhawk controller output is limited to 1580 (SERVO2MAX=1580).
In the Motor Test page, Test motor A button tests car motor, whose speed depends on Throttle %. Test motor B button tests steering servo:
-Throttle % 0: steering servo centered, wheels centered.
-Throttle % 50; steering servo moves wheels half way to left (as if steering stick to left, pulse longer than neutral).
-Throttle % 100: steering servo moves wheels full way to left (as if steering stick full to left, pulse at max length).
Unless I miss something, right steering is not tested.
If observing chin’s and chout’s indications:
Here steering stick is centered (ch1in=1571, ch1out=1517) and throttle stick is at maximum speed (ch2in=1904, ch2out=1579 (speed limited at the Pixhawk controller with SERVO2MAX=1580)). Mode is selected with the transmitter knob, being receiver ch3 connected to ch5 on the PPM encoder, giving ch5in=1070 (Manual mode, being MODE_CH=5).
On the PPM encoder, channels 3, 4, 6, 7 and 8 are open, so they are open inputs. Strangely, ch4in=ch6in=ch7in=ch8in=1498, but ch3in=899.
Recall that I can handle the car normally (with limited speed) in Manual, Acro and Steering modes, although with appreciable latency. Guided and Auto modes don’t work at all all possibly because a big error, as if in this modes the controller would not “know” to command steering for reaching the desired point.