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AP_MotorsMulticopter: battery voltage compensation improvements

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Leonard Hall 2016-05-22 19:23:22 +09:30 committed by Randy Mackay
parent 0ee7b00b0b
commit 7e0e0ca874
1 changed files with 18 additions and 12 deletions
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28
libraries/AP_Motors/AP_MotorsMulticopter.cpp
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@ -238,14 +238,15 @@ float AP_MotorsMulticopter::apply_thrust_curve_and_volt_scaling(float thrust) co
{
float throttle_ratio = thrust;
// apply thrust curve - domain 0.0 to 1.0, range 0.0 to 1.0
if (_thrust_curve_expo > 0.0f && !is_zero(_batt_voltage_filt.get())){
if (_thrust_curve_expo > 0.0f){
if(!is_zero(_batt_voltage_filt.get())) {
throttle_ratio = ((_thrust_curve_expo-1.0f) + safe_sqrt((1.0f-_thrust_curve_expo)*(1.0f-_thrust_curve_expo) + 4.0f*_thrust_curve_expo*_lift_max*thrust))/(2.0f*_thrust_curve_expo*_batt_voltage_filt.get());
} else {
throttle_ratio = ((_thrust_curve_expo-1.0f) + safe_sqrt((1.0f-_thrust_curve_expo)*(1.0f-_thrust_curve_expo) + 4.0f*_thrust_curve_expo*_lift_max*thrust))/(2.0f*_thrust_curve_expo);
}
}
// scale to maximum thrust point
throttle_ratio *= _spin_max;
return constrain_float(throttle_ratio, 0.0f, _spin_max);
return constrain_float(throttle_ratio, 0.0f, 1.0f);
}
// update_lift_max from battery voltage - used for voltage compensation
@ -262,14 +263,14 @@ void AP_MotorsMulticopter::update_lift_max_from_batt_voltage()
_batt_voltage_min = MAX(_batt_voltage_min, _batt_voltage_max * 0.6f);
// add current based voltage sag to battery voltage
float batt_voltage = _batt_voltage + _batt_current * _batt_resistance;
float batt_voltage = _batt_voltage + (_batt_current-_batt_current_resting) * _batt_resistance;
batt_voltage = constrain_float(batt_voltage, _batt_voltage_min, _batt_voltage_max);
// filter at 0.5 Hz
float bvf = _batt_voltage_filt.apply(batt_voltage/_batt_voltage_max, 1.0f/_loop_rate);
float batt_voltage_filt = _batt_voltage_filt.apply(batt_voltage/_batt_voltage_max, 1.0f/_loop_rate);
// calculate lift max
_lift_max = bvf*(1-_thrust_curve_expo) + _thrust_curve_expo*bvf*bvf;
_lift_max = batt_voltage_filt*(1-_thrust_curve_expo) + _thrust_curve_expo*batt_voltage_filt*batt_voltage_filt;
}
// update_battery_resistance - calculate battery resistance when throttle is above hover_out
@ -280,18 +281,23 @@ void AP_MotorsMulticopter::update_battery_resistance()
_batt_voltage_resting = _batt_voltage;
_batt_current_resting = _batt_current;
_batt_timer = 0;
} else {
} else if(_batt_voltage_resting < _batt_voltage && _batt_current_resting > _batt_current) {
// update battery resistance when throttle is over hover throttle
float batt_resistance = (_batt_voltage_resting-_batt_voltage)/(_batt_current-_batt_current_resting);
if ((_batt_timer < 400) && ((_batt_current_resting*2.0f) < _batt_current)) {
if (get_throttle() >= get_throttle_hover()) {
// filter reaches 90% in 1/4 the test time
_batt_resistance += 0.05f*(( (_batt_voltage_resting-_batt_voltage)/(_batt_current-_batt_current_resting) ) - _batt_resistance);
_batt_resistance += 0.05f*(batt_resistance - _batt_resistance);
_batt_timer += 1;
} else {
// initialize battery resistance to prevent change in resting voltage estimate
_batt_resistance = ((_batt_voltage_resting-_batt_voltage)/(_batt_current-_batt_current_resting));
_batt_resistance = batt_resistance;
}
}
// make sure battery resistance value doesn't result in the predicted battery voltage exceeding the resting voltage
if(batt_resistance < _batt_resistance){
_batt_resistance = batt_resistance;
}
}
}