AutoPilot

class AutoPilot

Provides basic auto-piloting utilities for a vessel. Created by calling Vessel.AutoPilot.

Note

If a client engages the auto-pilot and then closes its connection to the server, the auto-pilot will be disengaged. Its configuration and target are left unchanged.

Boolean SAS { get; set; }

The state of SAS.

Game Scenes:

Flight

Note

Equivalent to Control.SAS. Throws an exception if set to true while the auto-pilot is engaged, as the auto-pilot holds SAS off for as long as it is flying the vessel.

SASMode SASMode { get; set; }

The current AutoPilot.SASMode. These modes are equivalent to the mode buttons to the left of the navball that appear when SAS is enabled.

Game Scenes:

Flight

Note

Equivalent to Control.SASMode

Boolean Engaged { get; set; }

Whether the auto-pilot is engaged. Setting to true engages the auto-pilot; setting to false disengages it.

Game Scenes:

Flight

Boolean ShowInfoUI { get; set; }

Whether an in-game window showing the auto-pilot’s state (engagement, attitude error, target, angular rate, inner-loop PID gains and oscillation suppression) is displayed for this vessel. Defaults to false. This is a debugging aid; the window is reset to hidden when the game is restarted.

Game Scenes:

Flight

void Reset ()

Disengages the auto-pilot and resets all configuration parameters to their defaults. Also resets the target pitch, heading and roll, and clears all internal controller state, including the oscillation detector’s structural level — which otherwise persists across engagements so that a craft known to be flexible re-latches quickly.

Game Scenes:

Flight

ReferenceFrame ReferenceFrame { get; set; }

The reference frame for the target direction (AutoPilot.TargetDirection).

Game Scenes:

Flight

Note

An error will be thrown if this property is set to a reference frame that rotates with the vessel being controlled, as it is impossible to rotate the vessel in such a reference frame.

Single TargetPitch { get; set; }

The target pitch, in degrees, between -90° and +90°.

Game Scenes:

Flight

Note

A convenience for aiming the nose by angle. Heading (and hence roll) is ill-defined when the nose is near vertical (pitch → ±90°); near the vertical prefer AutoPilot.TargetDirection or AutoPilot.SetDirectionAndUp. The setter preserves the current roll relative to AutoPilot.UpReference.

Single TargetHeading { get; set; }

The target heading, in degrees, between 0° and 360°.

Game Scenes:

Flight

Note

A convenience for aiming the nose by angle, ill-defined when the nose is near vertical (pitch → ±90°) — see AutoPilot.TargetPitch. The setter preserves the current roll relative to AutoPilot.UpReference.

Single TargetRoll { get; set; }

The target roll, in degrees, measured about the vessel’s nose relative to the AutoPilot.UpReference (roll 0 aligns the vessel’s dorsal/roof axis with the reference; positive roll banks right). NaN if no target roll is set.

Game Scenes:

Flight

Note

When left unset (NaN) the auto-pilot suppresses roll rotation — it drives the roll rate to zero rather than holding a specific roll angle. Setting a value re-rolls the current target to that angle relative to the up reference while keeping the nose direction. With the default reference (the frame’s up) this reproduces the historical roll away from the vertical, and is ill-defined only when the nose points along the reference (near straight up or down). To hold a well-defined roll through the vertical — for example a gravity turn — set the up reference off the flight path (see AutoPilot.SetDirectionAndUp / AutoPilot.UpReference).

Tuple<Double, Double, Double> UpReference { get; set; }

The reference direction, in the reference frame specified by AutoPilot.ReferenceFrame, that AutoPilot.TargetRoll is measured against: at roll 0 the vessel’s dorsal (roof) axis is aligned with this vector’s component perpendicular to the nose. Defaults to the frame’s up (the zenith / radial-out direction).

Game Scenes:

Flight

Note

Setting this re-anchors how roll is measured without moving the current target, so the reference can be set once and then rolls commanded against it with AutoPilot.TargetRoll while the nose direction changes freely. It is also set as a side effect of AutoPilot.SetDirectionAndUp. Setting the target rotation, target direction, or the scalar pitch/heading leaves it unchanged. Choosing a reference off the flight path keeps roll well-defined through the vertical.

void TargetPitchAndHeading (Single pitch, Single heading)

Set target pitch and heading angles.

Parameters:

• pitch – Target pitch angle, in degrees between -90° and +90°.

• heading – Target heading angle, in degrees between 0° and 360°.

Game Scenes:

Flight

Note

A convenience for aiming the nose by angle; heading is ill-defined when the nose is near vertical (pitch → ±90°), so near the vertical prefer AutoPilot.TargetDirection or AutoPilot.SetDirectionAndUp. Preserves the current roll relative to AutoPilot.UpReference.

Tuple<Double, Double, Double> TargetDirection { get; set; }

Direction vector corresponding to the target pitch and heading. This is in the reference frame specified by AutoPilot.ReferenceFrame.

Game Scenes:

Flight

Tuple<Double, Double, Double, Double> TargetRotation { get; set; }

The target rotation quaternion. Setting this also sets the target roll. This is in the reference frame specified by AutoPilot.ReferenceFrame.

Game Scenes:

Flight

void SetDirectionAndUp (Tuple<Double, Double, Double> direction, Tuple<Double, Double, Double> up, Single roll = 0.0f)

Set the target attitude from a nose direction and an up vector: point the nose along direction and roll so the vessel’s dorsal (roof) axis aligns with up (its component perpendicular to the nose), then apply an optional roll offset about the nose. Both vectors are in the reference frame specified by AutoPilot.ReferenceFrame.

Parameters:

• direction – The direction to point the nose in.

• up – The reference direction the roof is rolled towards. Need not be normalized or perpendicular to direction — its component perpendicular to the nose is used. Stored as the AutoPilot.UpReference.

• roll – An additional roll about the nose, in degrees (positive banks right). Defaults to 0.

Game Scenes:

Flight

Note

This is the way to hold a well-defined orientation through a maneuver — for example a gravity turn: pass a fixed up (say north) and the roll stays defined the whole way, with no singularity at the vertical. It is well-defined for every nose direction except up parallel to direction (asking the roof to point where the nose already points), where it falls back to pointing the nose only. Equivalent to setting AutoPilot.UpReference to up, aiming at direction and setting AutoPilot.TargetRoll to roll.

Single CurrentTargetPitch { get; }

The current target pitch the auto-pilot is tracking, in degrees. When AutoPilot.TargetSmoothingTime is non-zero this lags the commanded AutoPilot.TargetPitch while a change is slewed in; otherwise the two are equal. A convenience scalar, ill-defined near the vertical — see AutoPilot.TargetPitch.

Game Scenes:

Flight

Single CurrentTargetHeading { get; }

The current target heading the auto-pilot is tracking, in degrees. When AutoPilot.TargetSmoothingTime is non-zero this lags the commanded AutoPilot.TargetHeading while a change is slewed in; otherwise the two are equal. A convenience scalar, ill-defined near the vertical — see AutoPilot.TargetHeading.

Game Scenes:

Flight

Single CurrentTargetRoll { get; }

The current target roll the auto-pilot is tracking, in degrees. When AutoPilot.TargetSmoothingTime is non-zero this lags the commanded AutoPilot.TargetRoll while a change is slewed in; otherwise the two are equal. NaN if no target roll is set.

Game Scenes:

Flight

Tuple<Double, Double, Double> CurrentTargetDirection { get; }

Direction vector corresponding to the current target pitch and heading (see AutoPilot.CurrentTargetPitch), in the reference frame specified by AutoPilot.ReferenceFrame. Lags AutoPilot.TargetDirection while a change is slewed in when AutoPilot.TargetSmoothingTime is non-zero.

Game Scenes:

Flight

Tuple<Double, Double, Double, Double> CurrentTargetRotation { get; }

The current target rotation quaternion the auto-pilot is tracking, in the reference frame specified by AutoPilot.ReferenceFrame. Lags AutoPilot.TargetRotation while a change is slewed in when AutoPilot.TargetSmoothingTime is non-zero.

Game Scenes:

Flight

void Wait (Double timeout = -1.0)

Blocks until the vessel is pointing in the target direction and has the target roll (if set). Throws an exception if the auto-pilot has not been engaged.

Parameters:

• timeout – Maximum time to wait in seconds. If not specified, waits indefinitely.

Game Scenes:

Flight

Single StoppingAngleThreshold { get; set; }

The threshold, in degrees, below which the pointing error must fall for AutoPilot.Wait to return. Defaults to 1 degree.

Game Scenes:

Flight

Single StoppingVelocityThreshold { get; set; }

The threshold angular velocity, in rad/s, below which the vessel’s angular velocity magnitude must fall for AutoPilot.Wait to return. Defaults to 0.05 rad/s.

Game Scenes:

Flight

Single Error { get; }

The error, in degrees, between the direction the ship has been asked to point in and the direction it is pointing in. Throws an exception if the auto-pilot has not been engaged and SAS is not enabled or is in stability assist mode.

Game Scenes:

Flight

Note

This is the error relative to the commanded target. While a change is being slewed in (see AutoPilot.TargetSmoothingTime) it differs from AutoPilot.CurrentError, the error relative to the target the auto-pilot is currently tracking.

Tuple<Double, Double, Double> AttitudeError { get; }

The per-axis attitude error (pitch, yaw, roll), in degrees, between the vessel’s current attitude and the commanded target. All three components come from one singularity-free residual decomposition, so they stay well-defined near the vertical (unlike a subtraction of pitch/heading/roll angles). The scalar AutoPilot.PitchError, AutoPilot.HeadingError and AutoPilot.RollError are the magnitudes of the pitch, yaw and roll components respectively. Throws an exception if the auto-pilot has not been engaged.

Game Scenes:

Flight

Single PitchError { get; }

The error, in degrees, between the vessels current and target pitch. Throws an exception if the auto-pilot has not been engaged.

Game Scenes:

Flight

Note

The pitch component of AutoPilot.AttitudeError — the pitch part of the direction error resolved in the roll-invariant frame, well-defined near the vertical.

Single HeadingError { get; }

The error, in degrees, between the vessels current and target heading. Throws an exception if the auto-pilot has not been engaged.

Game Scenes:

Flight

Note

The yaw component of AutoPilot.AttitudeError — the yaw part of the direction error resolved in the roll-invariant frame, well-defined near the vertical (unlike the absolute heading, which is undefined at the pole).

Single RollError { get; }

The error, in degrees, between the vessels current and target roll. Throws an exception if the auto-pilot has not been engaged or no target roll is set.

Game Scenes:

Flight

Note

Measured about the vessel’s nose axis, so it stays well-defined near the vertical singularity — unlike a subtraction of pitch/heading/roll angles, whose roll term is ill-conditioned when the vessel points close to straight up or down.

Single CurrentError { get; }

The error, in degrees, between the direction the auto-pilot is currently tracking and the direction the ship is pointing in. Unlike AutoPilot.Error (which is relative to the commanded target), this is relative to the slewed target the auto-pilot is currently holding, so it stays small while a smoothed change (see AutoPilot.TargetSmoothingTime) is fed in. Equal to AutoPilot.Error when smoothing is off. Throws an exception if the auto-pilot has not been engaged.

Game Scenes:

Flight

Tuple<Double, Double, Double> CurrentAttitudeError { get; }

The per-axis attitude error (pitch, yaw, roll), in degrees, between the vessel’s current attitude and the target the auto-pilot is currently tracking (the slewed target — see AutoPilot.CurrentTargetRotation). Like AutoPilot.AttitudeError but relative to the current target, so it stays small while a smoothed change (see AutoPilot.TargetSmoothingTime) is fed in; equal to AutoPilot.AttitudeError when smoothing is off. Throws an exception if the auto-pilot has not been engaged.

Game Scenes:

Flight

Single CurrentPitchError { get; }

The error, in degrees, between the vessels current pitch and the pitch the auto-pilot is currently tracking (see AutoPilot.CurrentTargetPitch). Throws an exception if the auto-pilot has not been engaged.

Game Scenes:

Flight

Note

The pitch component of AutoPilot.CurrentAttitudeError, well-defined near the vertical.

Single CurrentHeadingError { get; }

The error, in degrees, between the vessels current heading and the heading the auto-pilot is currently tracking (see AutoPilot.CurrentTargetHeading). Throws an exception if the auto-pilot has not been engaged.

Game Scenes:

Flight

Note

The yaw component of AutoPilot.CurrentAttitudeError, well-defined near the vertical.

Single CurrentRollError { get; }

The error, in degrees, between the vessels current roll and the roll the auto-pilot is currently tracking (see AutoPilot.CurrentTargetRoll). Throws an exception if the auto-pilot has not been engaged or no target roll is set.

Game Scenes:

Flight

Note

Measured about the vessel’s nose axis, so it stays well-defined near the vertical singularity — see AutoPilot.RollError.

Double RollStartAngle { get; set; }

The direction error, in degrees, above which roll blending is fully suppressed. Defaults to 20 degrees.

Game Scenes:

Flight

Double RollEngageAngle { get; set; }

The direction error, in degrees, below which roll is fully engaged. Roll blends linearly between AutoPilot.RollStartAngle and this value. Defaults to 15 degrees.

Game Scenes:

Flight

Tuple<Double, Double, Double> MaxAngularVelocity { get; set; }

The maximum angular velocity of the vessel, in rad/s, for each of the pitch, roll and yaw axes. Limits the target angular velocity computed by the bang-bang profile so that vessels with very high torque availability do not spin faster than desired. Defaults to 1 rad/s for each axis.

Game Scenes:

Flight

Double PitchYawAttenuationAngle { get; set; }

The angle, in degrees, at which the autopilot considers the vessel to be pointing close to the target direction. This sets the high angle of the pitch/yaw pointing deadband: at or above this error the target velocity is at full, and below it the target velocity ramps linearly to zero at half this angle, so the vessel coasts to a stop. Pitch and yaw are controlled jointly, so a single angle applies to both. Defaults to 1°.

Game Scenes:

Flight

Double RollAttenuationAngle { get; set; }

The angle, in degrees, at which the autopilot considers the vessel to be pointing close to the target roll. This sets the high angle of the roll-axis pointing deadband: at or above this error the target velocity is at full, and below it the target velocity ramps linearly to zero at half this angle, so the roll coasts to a stop. Defaults to 1°.

Game Scenes:

Flight

Boolean AutoTune { get; set; }

Whether the rotation rate controllers PID parameters should be automatically tuned using the vessels moment of inertia and available torque. Defaults to true. See AutoPilot.TimeToPeak and AutoPilot.Overshoot.

Game Scenes:

Flight

Tuple<Double, Double, Double> TimeToPeak { get; set; }

The target time to peak used to autotune the PID controllers. A vector of three times, in seconds, for each of the pitch, roll and yaw axes. Defaults to 1 second for each axis.

Game Scenes:

Flight

Double SoftStartTime { get; set; }

The duration, in seconds, over which the control output is faded in when the autopilot is engaged. This soft-start spreads the engagement transient over many physics ticks so engaging (on the pad or mid-flight) does not command a near-maximum control deflection that can excite an oscillation. Defaults to 0.5 seconds. Set to 0 to disable the fade-in.

Game Scenes:

Flight

Double TargetSmoothingTime { get; set; }

The duration, in seconds, over which a change to the target attitude is applied to the control target. When set above zero, changing the target pitch, heading, roll, direction or rotation makes the effective control target ramp smoothly (a constant-rate rotation) from its current value to the new value over this many seconds, rather than jumping instantly. This lets a slow control loop drive a smooth maneuver (for example a gravity turn) without inducing oscillation from stepwise target changes. Defaults to 0 (instantaneous).

Game Scenes:

Flight

Tuple<Double, Double, Double> Overshoot { get; set; }

The target overshoot percentage used to autotune the PID controllers. A vector of three values, between 0 and 1, for each of the pitch, roll and yaw axes. Defaults to 0.01 for each axis.

Game Scenes:

Flight

Tuple<Double, Double, Double> PitchPIDGains { get; set; }

Gains for the pitch PID controller.

Game Scenes:

Flight

Note

When AutoPilot.AutoTune is true, these values are updated automatically, which will overwrite any manual changes.

Tuple<Double, Double, Double> RollPIDGains { get; set; }

Gains for the roll PID controller.

Game Scenes:

Flight

Note

When AutoPilot.AutoTune is true, these values are updated automatically, which will overwrite any manual changes.

Tuple<Double, Double, Double> YawPIDGains { get; set; }

Gains for the yaw PID controller.

Game Scenes:

Flight

Note

When AutoPilot.AutoTune is true, these values are updated automatically, which will overwrite any manual changes.

RateFilterMode PitchYawRateFilterMode { get; set; }

Controls the rate-feedback filtering (the wobble-suppression filter on the measured angular velocity) for the pitch and yaw axes of a structurally flexible vessel. When RateFilterMode.Automatic (the default) the auto-pilot detects the oscillation at runtime, estimates its frequency and routes it to the appropriate tool (a notch filter for a low-frequency mode near the control band, a low-pass for a high-frequency mode). RateFilterMode.Off disables rate filtering only — the other oscillation mitigations are unaffected. RateFilterMode.Notch and RateFilterMode.LowPass force the respective tool unconditionally at AutoPilot.PitchYawOscillationFrequency, for a vessel known in advance to be flexible.

Game Scenes:

Flight

RateFilterMode RollRateFilterMode { get; set; }

Controls the rate-feedback filtering for the roll axis. Behaves as AutoPilot.PitchYawRateFilterMode but for roll, using AutoPilot.RollOscillationFrequency. Defaults to RateFilterMode.Automatic.

Game Scenes:

Flight

Double PitchYawOscillationFrequency { get; set; }

The structural mode frequency, in Hz, for the pitch/yaw axis group. Used directly as the filter frequency in RateFilterMode.Notch / RateFilterMode.LowPass mode, and as the seed for the automatic frequency estimator before it acquires. Defaults to 1.5 Hz.

Game Scenes:

Flight

Double RollOscillationFrequency { get; set; }

The structural mode frequency, in Hz, for the roll axis. Behaves as AutoPilot.PitchYawOscillationFrequency but for roll. Defaults to 1.5 Hz.

Game Scenes:

Flight

Double OscillationNotchQ { get; set; }

The quality factor of the notch filter used to suppress a low-frequency structural mode. A higher value gives a narrower notch (less in-band control lag but less tolerance to the mode frequency drifting); a lower value gives a wider notch. Defaults to 2.5. This is an advanced tuning parameter.

Game Scenes:

Flight

MitigationMode OscillationBandwidthFloorMode { get; set; }

Controls the bandwidth-floor mitigation: the reduction of the inner control loop bandwidth on a structurally flexible axis — the primary oscillation stabilizer. When MitigationMode.Automatic (the default) it engages on a latched axis while holding (and during a detected limit cycle). MitigationMode.Off never reduces the bandwidth; MitigationMode.Forced keeps it fully reduced at all times.

Game Scenes:

Flight

Double OscillationBandwidthFloor { get; set; }

The inner control loop bandwidth, in rad/s, that an axis is reduced towards while the bandwidth-floor mitigation is engaged on it. Lowering it suppresses oscillation more strongly; raising it keeps more control authority at the cost of allowing more wobble. Defaults to 1 rad/s. This is an advanced tuning parameter.

Game Scenes:

Flight

MitigationMode OscillationFeedforwardMode { get; set; }

Controls the feedforward-cut mitigation: removal of the acceleration feedforward on a structurally flexible axis while holding, so it cannot re-excite a residual mode at the reduced bandwidth. When MitigationMode.Automatic (the default) it follows the hold gate on a latched axis. MitigationMode.Off never cuts the feedforward; MitigationMode.Forced always cuts it fully.

Game Scenes:

Flight

MitigationMode OscillationOutputFilterMode { get; set; }

Controls the output-smoothing mitigation: a low-pass on the delivered actuator command that caps residual control chatter. When MitigationMode.Automatic (the default) it engages on a latched axis (and, lightly, while the oscillation detector is firing on an unlatched one). MitigationMode.Off never smooths; MitigationMode.Forced smooths fully at all times.

Game Scenes:

Flight

Double PitchYawControlOscillation { get; }

The current amplitude of control-output oscillation on the pitch/yaw axis group, measured as the deviation of the delivered control about its slowly-varying trim. A settled hold sits near zero; a sustained limit cycle drives it toward 1. Read-only.

Game Scenes:

Flight

Double RollControlOscillation { get; }

The current amplitude of control-output oscillation on the roll axis, measured as the deviation of the delivered control about its slowly-varying trim. Read-only. See AutoPilot.PitchYawControlOscillation.

Game Scenes:

Flight

Tuple<Double, Double, Double> OscillationLevel { get; }

A measure, between 0 and 1 for each of the pitch, roll and yaw axes, of how strongly the auto-pilot currently detects structural oscillation (wobble) on that axis. 0 means none detected; values approaching 1 mean a sustained structural oscillation. Read-only.

Game Scenes:

Flight

Boolean PitchYawOscillationLatched { get; }

Whether the auto-pilot has confirmed the pitch/yaw axes to be structurally flexible and latched oscillation suppression on for them. Read-only. See AutoPilot.PitchYawRateFilterMode.

Game Scenes:

Flight

Boolean RollOscillationLatched { get; }

Whether the auto-pilot has confirmed the roll axis to be structurally flexible and latched oscillation suppression on for it. Read-only. See AutoPilot.RollRateFilterMode.

Game Scenes:

Flight

Double PitchYawOscillationDetectedFrequency { get; }

The structural oscillation frequency, in Hz, estimated by the automatic detector for the pitch/yaw axis group, or NaN until the estimator acquires. The estimator runs in all modes, so this is observable even when suppression is off or forced. Read-only.

Game Scenes:

Flight

Double RollOscillationDetectedFrequency { get; }

The structural oscillation frequency, in Hz, estimated by the automatic detector for the roll axis, or NaN until the estimator acquires. Read-only. See AutoPilot.PitchYawOscillationDetectedFrequency.

Game Scenes:

Flight

Boolean DiagnosticLogging { get; set; }

When true, records one row of diagnostic data per physics tick to an in-memory buffer (see AutoPilot.DiagnosticLog), and echoes each row to Player.log prefixed with [KRPC.AP]. The data is CSV: the first row is a header naming every column, and each subsequent row records the auto-pilot’s full control-loop state for one tick (setpoints, errors, measured rates, gains, velocity-profile and feedforward internals, control outputs, and the oscillation detector/gate/mitigation state). The buffer is capped at 3000 data rows (one minute at the 50 Hz physics rate); when full, this property switches itself back to false and the buffer holds the minute following the enable. Setting to true clears the buffer. Defaults to false.

Game Scenes:

Flight

String DiagnosticLog { get; }

The diagnostic log collected since AutoPilot.DiagnosticLogging was last set to true: CSV text whose first line is the column header and each subsequent line records one physics tick. Vector-valued channels use one column per component (suffixed .p/.r/.y for pitch, roll, yaw); pitch-yaw-group/roll channel pairs are suffixed .py/.roll. Returns an empty string if diagnostic logging has not been enabled or no ticks have occurred.

Game Scenes:

Flight

enum RateFilterMode

Controls the auto-pilot’s rate-feedback filtering for an axis group — the mitigation that removes a structural oscillation (wobble) from the measured angular velocity before the control loops consume it. See AutoPilot.PitchYawRateFilterMode and AutoPilot.RollRateFilterMode.

Automatic

The default. The auto-pilot detects structural oscillation at runtime, estimates its frequency and routes it to the appropriate filter: a notch for a low-frequency mode near the control band, a low-pass for a high-frequency mode, or a broadband low-pass while the frequency is not yet known. Rigid vessels are left untouched.

Off

No rate filtering. The other oscillation mitigations are unaffected.

Notch

Force a notch filter at the manually set frequency (AutoPilot.PitchYawOscillationFrequency / AutoPilot.RollOscillationFrequency), for a vessel whose structural mode is known in advance.

LowPass

Force a low-pass filter derived from the manually set frequency.

enum MitigationMode

Controls one of the auto-pilot’s individually-toggleable oscillation mitigations (AutoPilot.OscillationBandwidthFloorMode, AutoPilot.OscillationFeedforwardMode, AutoPilot.OscillationOutputFilterMode).

Automatic

The default: the mitigation engages automatically, driven by the runtime oscillation detector and the hold gate. Rigid vessels are left untouched.

Off

The mitigation never engages. The other mitigations are unaffected.

Forced

The mitigation is fully engaged at all times, regardless of what the oscillation detector reports.