Steer by wire
analog => PWM (speed dependent conversion) by round boostcontrol function.
Measured analog voltage output of the joystick.
- extreme left turn: 1.25 V
- just in the middle: 2.5 V (trimmed to mid-position)
- extreme right turn: 3.88 V
With extreme trimming 0-5V can be reached (though not at the same trimming-position). Joystick powered from dedicated 5V regulator, as the servo-supply was "nervous" during servo movements.
Needs extensive testing. Use only at non-lethal vehicle speeds (max 40km/h in a protected chassis).
- steering can be configured with 17 point curve.
- At higher wheelspeed the steering the end-positions are narrowed
Special Round feature
- Needs special 0.5.2 firmware
- Use the second Analog input ( Dsub15/pin 5 )for wheel input
- the analog value will limited in firmware:
- 0..10km/h: no limit ( 0-5V )
- 10-26km/h: limit gradually 0..50%. For example at 18km/h (used min: 0.6V ... max: 4.4V so first 2 and last 2 configured values cannot be reached).
- 26km/h...: limit 50% ( used min: 1.25V; max: 3.75V so first 4 and last 4 configured values cannot be reached).
- the limited analog value goes through the 17 point analog input 2 curve
- the result of the curve goes out on the pwm_0 output ( Dsub15/pin 2 )
- the analog value will limited in firmware:
Servo data
Tested with v3 boost alternate function 1.1.8x firmware
- 375 Hz
- inverted p259 output pulled up to +5V
- 25 .. 99% output was reasonable
Achieved best results with 57 Hz PWM frequency, pulse high for appr. 1-2 msec. The time of low level seems to not make a difference in position-command. But at higher freq the servo was a bit nervous with more small back-n-forth adjustments.