[PIPython] SegWay scooter

[bruno]

Ciao a tutti

ho trovato un progetto di massima per uno scooter autobilanciato;il
progettista dichiara che il programma che interfaccia il giroscopio e
che gestisce il controller dei motori e'stato scritto in Python e
successivamente in C.
Rende disponibile il pseudocode dell'algoritmo del bilanciamento (vedi
sotto); partendo da questo e' possibile risalire ad un programma?
Non so quanto interessante o stupida possa essere la domanda, ma spero
comunque in una risposta

bruno

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Putting it all together
What takes many paragraphs to explain is surprisingly simple to code.
Here is the basic pseudocode of the balance algorithm, complete with the
numbers which made my scooter feel stable and responsive. 

Inputs
        angle, angle_rate: the tilt angle of the scooter in radians and
        its derivative in radians/sec 
        steer_knob: the reading from the steering knob, between -1 and
        +1. 
Balance
        balance_torque = 5.0 * (angle - rest_angle) + 0.4 * angle_rate
Limit top speed by tilting back
        overspeed = max(0, cur_speed - 0.5)
        if (overspeed > 0) { 
          overspeed_integral = min(0.4, overspeed_integral + min(0.2,
        overspeed+0.05) * dt) 
        } 
        else { 
          overspeed_integral = max(0, overspeed_integral - 0.04*dt) 
        } 
        rest_angle = 0.4*overspeed + 0.7*overspeed_integral
Steer. Decrease steering rate at high speed
        steer_cmd = 0.07/(0.3+abs(cur_speed)) * steer_knob
Track current speed
        cur_speed += 1.2 * balance_torque * dt
Differential steering
        left_motor_pwm = balance_torque + cur_speed + steer_cmd 
        right_motor_pwm = balance_torque + cur_speed - steer_cmd
Outputs
        left_motor_pwm and right_motor_pwm directly set the duty cycle
        of the pulse width modulator for the wheel controller, and range
        from -1 to +1 (+1 is 100% forward, -1 is 100% reverse.)
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