public Ahrs(
IObservable <AngularVelocity3> angularVelocity,
IObservable <GForce3> acceleration,
IObservable <MagneticFluxDensity3> magnetism,
MagneticFluxDensity3 magnetismMinCalibration,
MagneticFluxDensity3 magnetismMaxCalibration)
{
_angularVelocity = angularVelocity;
_acceleration = acceleration;
_magnetism = magnetism;
_magnetismMinCalibration = magnetismMinCalibration;
_magnetismMaxCalibration = magnetismMaxCalibration;
}
public static WindowsPilot Create(
IAircraft aircraft,
IGyroscope3 gyroscope,
IAccelerometer3 accelerometer,
IMagnetometer3 magnetometer,
IFlightController controller,
double thrustMax,
double angularPositionPitchMax,
double angularPositionRollMax,
double angularVelocityYawMax)
{
var angularVelocityNoisy = new Subject <AngularVelocity3>();
var accelerationNoisy = new Subject <GForce3>();
var magnetismNoisy = new Subject <MagneticFluxDensity3>();
IObservable <AngularVelocity3> angularVelocityOptimal =
angularVelocityNoisy
.Filter(
estimatedMeasurementNoiseCovariance: 0.0000025d,
estimatedProcessNoiseCovariance: 0d,
controlWeight: 0.5d * OutputFrequency / gyroscope.Frequency,
initialEstimate: 0d,
initialErrorCovariance: 1d)
.Multiply(1.08d /*calibration*/);
IObservable <GForce3> accelerationOptimal =
accelerationNoisy
.Filter(
estimatedMeasurementNoiseCovariance: 0.025d,
estimatedProcessNoiseCovariance: 0d,
controlWeight: 0.5d * OutputFrequency / accelerometer.Frequency,
initialEstimate: 0d,
initialErrorCovariance: 1d);
IObservable <MagneticFluxDensity3> magnetismOptimal =
magnetismNoisy
.Filter(
estimatedMeasurementNoiseCovariance: 0.05d,
estimatedProcessNoiseCovariance: 0d,
controlWeight: 0.5d * OutputFrequency / magnetometer.Frequency,
initialEstimate: 0d,
initialErrorCovariance: 1d);
var magnetismMinCalibration = new MagneticFluxDensity3(
x: -0.273980716005263d,
y: -0.245318477916743d,
z: -0.237557110710227d);
var magnetismMaxCalibration = new MagneticFluxDensity3(
x: 0.148042531751317d,
y: 0.177504483195312d,
z: 0.155796981828076d);
var ahrs = new Ahrs(angularVelocityOptimal, accelerationOptimal, magnetismOptimal, magnetismMinCalibration, magnetismMaxCalibration);
var angularVelocityInterval = TimeSpan.FromTicks(Convert.ToInt64(TimeSpan.TicksPerSecond / gyroscope.Frequency));
var accelerationInterval = TimeSpan.FromTicks(Convert.ToInt64(TimeSpan.TicksPerSecond / accelerometer.Frequency));
var magnetismInterval = TimeSpan.FromTicks(Convert.ToInt64(TimeSpan.TicksPerSecond / magnetometer.Frequency));
var yawTimer = new Subject <object>();
var yawInterval = TimeSpan.FromTicks(Convert.ToInt64(TimeSpan.TicksPerSecond / YawFrequency));
var outputTimer = new Subject <object>();
var outputInterval = TimeSpan.FromTicks(Convert.ToInt64(TimeSpan.TicksPerSecond / OutputFrequency));
SyncLoop.ProduceAsync(
angularVelocityInterval, a => gyroscope.Read(), angularVelocityNoisy,
accelerationInterval, a => accelerometer.Read(), accelerationNoisy,
magnetismInterval, a => magnetometer.Read(), magnetismNoisy,
yawInterval, a => null, yawTimer,
outputInterval, a => null, outputTimer,
WorkItemPriority.High).AsTask();
IObservable <double> thrust =
controller.Thrust.Select(value => value * thrustMax);
IObservable <double> angularPositionPitchSetpoint =
controller.Pitch.Select(value => value * angularPositionPitchMax);
IObservable <double> angularPositionRollSetpoint =
controller.Roll.Select(value => value * angularPositionRollMax);
IObservable <double> angularPositionYawSetpoint =
Extensions.ObservableExtensions
.CombineLatest(
controller.Yaw,
yawTimer.TimeInterval(),
(yaw, timer, yawChanged, timerChanged) =>
new { Yaw = yaw, YawChanged = yawChanged, TimerElapsed = timerChanged, TimerInterval = timer.Interval })
.Scan(
default(double),
(accu, t) =>
{
double yaw = accu;
if (t.TimerElapsed)
{
double dt = t.TimerInterval.TotalSeconds;
yaw += t.Yaw * angularVelocityYawMax * dt;
if (yaw > AngleConvert.ToRadians(180d))
{
yaw -= AngleConvert.ToRadians(360d);
}
else if (yaw <= AngleConvert.ToRadians(-180d))
{
yaw += AngleConvert.ToRadians(360d);
}
}
return(yaw);
});
IObservable <EulerAngles> angularPositionSetpoint =
Observable.CombineLatest(
angularPositionPitchSetpoint,
angularPositionRollSetpoint,
angularPositionYawSetpoint,
(pitch, roll, yaw) =>
new EulerAngles(pitch, roll, yaw));
var pilot = new WindowsPilot(
aircraft,
thrust,
angularPositionSetpoint,
ahrs.AngularVelocityCalibrated,
ahrs.AngularPosition);
outputTimer.Subscribe(state => pilot.WriteOutput());
return(pilot);
}
public static IObservable <Vector3> ToDirection(this IObservable <MagneticFluxDensity3> source, MagneticFluxDensity3 min, MagneticFluxDensity3 max)
{
return(source
.Select(magnetism =>
{
return new Vector3(
x: 2d * (magnetism.X - min.X) / (max.X - min.X) - 1d,
y: 2d * (magnetism.Y - min.Y) / (max.Y - min.Y) - 1d,
z: 2d * (magnetism.Z - min.Z) / (max.Z - min.Z) - 1d).Normalize();
}));
}
