Implement launch azimuth and refine node execution.
This commit is contained in:
Casper V. Kristensen
parent
f346414b1a
commit
08246d4d83
GPG key ID:
B1156723DB3BDDA8
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@ -1,5 +1,39 @@
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CLEARSCREEN.
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print "=================== BOOTING ===================".
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switch to 0.
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if HOMECONNECTION:ISCONNECTED {
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update_scripts().
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} else {
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print "No connection to KSC: not updating scripts.".
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}
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print "============= BOOT SEQUENCE COMPLETE =============".
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function update_scripts {
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// Copy all .ks-files from the archive to the CPU's internal storage.
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// Get lexicon of existing items (files/directories) and sizes on the internal storage
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local existing is lexicon().
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for item in CORE:VOLUME:FILES:VALUES {
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set existing[item:NAME] to item:SIZE.
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}
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// Check if items from the archive match those in the internal storage
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for item in VOLUME("ARCHIVE"):FILES:VALUES {
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local skip is false. // kOS doesn't support the 'continue' keyword...
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if not skip and item:NAME[0] = "." set skip to true. // skip linux hidden dirs (e.g. .git)
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if not skip and item:ISFILE
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and item:EXTENSION <> "ks" set skip to true. // skip non-script items (e.g. README.md)
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if not skip and existing:HASKEY(item:NAME)
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and item:SIZE = existing[item:NAME] set skip to true. // skip if local item is same size
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if not skip {
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print "Copying " + item:NAME + "..".
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COPYPATH(PATH(VOLUME("ARCHIVE")):COMBINE(item:NAME), CORE:VOLUME).
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if item:NAME = "boot" reboot. // reboot CPU if boot/ directory was updated
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}
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}
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}
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155
launch.ks
155
launch.ks
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@ -2,81 +2,124 @@ run once util.
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run once vectors.
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run once node.
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print "====================== LAUNCHING ======================".
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parameter orbit_height is 100_000.
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parameter pitchover_tilt is 20.
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parameter pitchover_altitude is 1000.
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parameter pitchover_velocity is 100.
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function launch {
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// Launch to orbit of provided altitude and inclination.
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parameter target_orbit_altitude is 100_000. // meters
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parameter target_orbit_inclination is 0. // 0-180 degrees
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parameter pitchover_tilt is 20. // how many degrees to tilt at pitchover maneuver
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parameter pitchover_altitude is 1000. // perform pitchover at this altitude
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parameter pitchover_velocity is 100. // or this velocity
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// Auto-stage when the stage has no solid- and liquid fuel left
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when (STAGE:SOLIDFUEL + STAGE:LIQUIDFUEL < 1) and STAGE:READY then {
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print "STAGING (zero fuel)".
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STAGE.
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return true. // preserve trigger
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}
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print "========= LAUNCHING =========".
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print "Target orbital altitude: " + target_orbit_altitude + "m".
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print "Target orbital inclination: " + target_orbit_inclination + "°".
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print "Pitchover tilt: " + pitchover_tilt + "°".
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print "Pitchover at: " + pitchover_altitude + "m or " + pitchover_velocity + " m/s".
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print " ".
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// Automatically deploy solar panels at 0 atmosphere
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when SHIP:DYNAMICPRESSURE = 0 then {
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print "Deploying solar panels (zero pressure)".
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PANELS ON.
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}
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// Disable engine gimbal when engine is off
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on (not THROTTLE) { // using not to cast to boolean
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list engines in engines_list.
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for engine in engines_list {
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if engine:HASGIMBAL set engine:GIMBAL:LOCK to not THROTTLE.
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// LAUNCH AZIMUTH
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// Since the "center" of an orbit must be at the center of gravity of the body, the latitude of the launch site establishes the minimum absolute orbital inclination.
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// KSC is almost on the equator, so we're going to always round the latitude towards zero, and accept the inaccuracies it may introduce.
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local launch_site_latitude is round_towards_zero(SHIP:LATITUDE).
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local target_orbit_inclination is MAX(target_orbit_inclination, launch_site_latitude).
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// Calculate the launch azimuth; the compass heading we head for when launching to achieve orbit of desired inclination
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local launch_azimuth is calculate_launch_azimuth(target_orbit_inclination, target_orbit_altitude, launch_site_latitude).
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// If the latitude of the launch site is negative (ship is in the southern hemisphere), launch southwards instead of northwards
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local southwards is launch_site_latitude < 0.
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if southwards {
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set launch_azimuth to 180 - launch_azimuth.
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}
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print "Launch site latitude: " + ROUND(SHIP:LATITUDE, 3) + "° (~" + launch_site_latitude + "°)".
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print "Available orbital inclination: " + target_orbit_inclination + "°".
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print "Launch azimuth: " + ROUND(launch_azimuth, 3) + "°".
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print "Launch southwards: " + southwards.
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print "--- VERTICAL CLIMB ---".
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SAS OFF.
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set NAVMODE to "SURFACE".
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lock STEERING to HEADING(launch_azimuth, 90). // roll to launch azimuth
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lock THROTTLE to 1.0.
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STAGE.
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// Enable auto-stage when the maximum engine thrust changes (i.e. some engines ran out of fuel)
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on SHIP:MAXTHRUSTAT(0) {
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when STAGE:READY then {
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print "STAGING".
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STAGE.
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}.
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return true. // preserve trigger
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}
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}
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// VERTICAL CLIMB
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print "VERTICAL CLIMB to " + pitchover_altitude + "m or " + pitchover_velocity + "m/s".
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SAS OFF.
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set NAVMODE to "SURFACE".
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lock THROTTLE to 1.0.
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lock STEERING to HEADING(90,90).
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// Once a certain altitude is reached, a slight turn is made, called the pitchover maneuver
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wait until SHIP:ALTITUDE > pitchover_altitude
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// Once a certain altitude (or velocity) is reached, a slight turn is made, called the pitchover maneuver
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wait until SHIP:ALTITUDE > pitchover_altitude
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or SHIP:VELOCITY:SURFACE:MAG > pitchover_velocity.
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// PITCHOVER MANEUVER
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print "--- PITCHOVER ---".
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lock STEERING to HEADING(launch_azimuth, 90-pitchover_tilt).
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print "PITCHOVER by " + pitchover_tilt + "°".
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lock STEERING to HEADING(90,90-pitchover_tilt).
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wait until actual_prograde_pitch() > pitchover_tilt.
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wait until actual_prograde_pitch() > pitchover_tilt. // wait until the prograde "catches up" to our tilted heading
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// GRAVITY TURN
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print "--- GRAVITY TURN ---".
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// TODO: the angle of the launch azimuth will not account for the fact that our compass will change as we move north/south.
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lock STEERING to HEADING(launch_azimuth, 90-actual_prograde_pitch()). // Follow prograde pitch to get 0 deg angle of attack, but force compass heading at launch azimuth.
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print "GRAVITY TURN".
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lock STEERING to HEADING(90, 90-actual_prograde_pitch()). // follow prograde to get 0 deg angle of attack, but force compass heading 90 (east)
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wait until APOAPSIS > orbit_height.
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lock THROTTLE TO 0.
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unlock STEERING.
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wait until APOAPSIS > target_orbit_altitude.
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lock THROTTLE TO 0.
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unlock_control().
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// CREATE AND EXECUTE CIRCULARIZATION MANEUVER NODE
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create_circularization_node().
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execute_node().
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print "--- CIRCULARIZE ---".
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print "Waiting for ship to leave the atmosphere..".
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set KUNIVERSE:TIMEWARP:RATE to 4.
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wait until SHIP:DYNAMICPRESSURE = 0. // don't create maneuver node until we are out of the atmosphere - otherwise the apoapsis altitude and eta will change due to drag
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KUNIVERSE:TIMEWARP:CANCELWARP().
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print "Deploying solar panels".
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PANELS ON.
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// Create maneuver node that will circularize the orbit.
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// NOTE: Potential errors in the inclination are not fixed, since we are most likely going to change our orbit, which will make the inclination change cheaper later on.
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local node is NODE(TIME:SECONDS + ETA:APOAPSIS, 0, 0, 0).
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// Burn magnitude in the prograde direction is the difference between the required velocity to acheive orbit at apoapsis altitude and our velocity at apoapsis
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set node:PROGRADE to orbital_velocity(APOAPSIS) - VELOCITYAT(SHIP, TIME:SECONDS + ETA:APOAPSIS):ORBIT:MAG.
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add node.
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execute_node().
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// EPILOGUE
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print "========= LAUNCH SEQUENCE COMPLETE =========".
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unlock_control().
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}
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// Ensure that the throttle will be 0 when execution stops
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set SHIP:CONTROL:PILOTMAINTHROTTLE to 0.
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// Ensure that the player is not locked out of control.
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set SHIP:CONTROL:NEUTRALIZE to true.
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unlock STEERING.
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unlock THROTTLE.
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function calculate_launch_azimuth {
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// Calculate the launch azimuth; the compass heading we head for when launching to achieve orbit of desired inclination.
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// http://www.orbiterwiki.org/wiki/Launch_Azimuth
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// https://www.princeton.edu/~stengel/MAE342Lecture4.pdf
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parameter target_orbit_inclination.
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parameter target_orbit_altitude. // to compensate for the rotation of the body, we need to know the velocity of the target orbit, which is calculated from its altitude
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parameter launch_site_latitude.
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print "====================== LAUNCH SEQUENCE COMPLETE ======================".
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local inertial_azimuth is ARCSIN(COS(target_orbit_inclination) / COS(launch_site_latitude)). // azimuth in inertial space, that is, disregarding the rotation of the body
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local equatorial_rotational_velocity is (2 * CONSTANT:PI * BODY:RADIUS) / BODY:ROTATIONPERIOD.
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local target_orbit_velocity is orbital_velocity(target_orbit_altitude). // velocity of target orbit
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local launch_vector_x_component is target_orbit_velocity * SIN(inertial_azimuth) - equatorial_rotational_velocity * COS(launch_site_latitude).
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local launch_vector_y_component is target_orbit_velocity * COS(inertial_azimuth).
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return ARCTAN2(launch_vector_x_component, launch_vector_y_component).
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}
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launch(100_000, 0).
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81
node.ks
81
node.ks
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@ -1,72 +1,57 @@
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run once util.
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function estimated_burn_duration {
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// Calculate estimated burn duration for a maneuver node
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// https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
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// https://space.stackexchange.com/questions/27375/how-do-i-calculate-a-rockets-burn-time-from-required-velocity
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parameter node is NEXTNODE.
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local exhaust_velocity is isp_sum() * (CONSTANT:G * KERBIN:MASS).
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return ((SHIP:MASS * exhaust_velocity) / SHIP:MAXTHRUST) * (1 - CONSTANT:E^(-node:DELTAV:MAG/exhaust_velocity)).
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}
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function execute_node {
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parameter node is NEXTNODE.
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parameter precision is 0.05. // m/s delta-v
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print "EXECUTE MANEUVER NODE".
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local burn_duration is estimated_burn_duration(node).
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// Calculate estimated burn time
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// https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
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// https://space.stackexchange.com/questions/27375/how-do-i-calculate-a-rockets-burn-time-from-required-velocity
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local isp_sum is 0.
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list ENGINES in engines_list.
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for engine in engines_list {
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if engine:STAGE = STAGE:NUMBER set ISP_sum to ISP_sum + engine:VISP.
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}
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print "=== EXECUTE MANEUVER NODE ===".
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print "Estimated burn duration: " + ROUND(burn_duration, 1) + "s".
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local ve is ISP_sum * (CONSTANT:G * KERBIN:MASS). // exhaust velocity
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local burn_time is ((SHIP:MASS * ve) / SHIP:MAXTHRUST) * (1 - CONSTANT:E^(-node:BURNVECTOR:MAG/ve)).
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print "Estimated burn time: " + ROUND(burn_time).
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print "Aligning ship with burn vector".
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print "Aligning ship with burn vector..".
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SAS OFF.
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lock STEERING to node:BURNVECTOR.
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wait until VANG(SHIP:FACING:VECTOR, node:BURNVECTOR) < 0.1.
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lock STEERING to node:DELTAV.
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wait until VANG(SHIP:FACING:VECTOR, node:DELTAV) < 0.1.
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print "Initializing warp".
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unlock STEERING. // TODO: Doesnt work?
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warp_for(MAX(0, node:ETA - (burn_time/2) - 5)). // Warp until 5s before node
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unlock_control().
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warp_for(MAX(0, node:ETA - (burn_duration/2) - 5)). // warp until 5s before node
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print "Approaching".
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lock STEERING to node:BURNVECTOR.
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wait until node:ETA <= burn_time/2.
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lock STEERING to node:DELTAV.
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wait until node:ETA <= ROUND(burn_duration/2).
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print "Burn!".
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lock THROTTLE to 1.0.
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//throttle is 100% until there is less than 1 second of time left to burn
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//when there is less than 1 second - decrease the throttle linearly
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// TODO: Smooth at the end
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wait until node:DELTAV:MAG < 5.0. // TODO
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// Decrease throttle linearly when the burn duration is less than 1 second
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wait until estimated_burn_duration(node) <= 1.
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lock THROTTLE to MAX(0.01, estimated_burn_duration(node)). // ensure we always finish by burning with at least 1% power
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wait until node:DELTAV:MAG < precision.
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set THROTTLE to 0.0.
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print "DONE! Removing node and unlocking steering".
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print "=== MANEUVER NODE EXECUTED ===".
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print ROUND(node:DELTAV:MAG, 3) + "m/s delta-v remaining".
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unlock_control().
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wait 1.
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remove node.
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unlock STEERING.
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unlock THROTTLE.
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SET SHIP:CONTROL:PILOTMAINTHROTTLE TO 0.
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}
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function create_circularization_node {
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// parameter where.
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print "CREATE CIRCULARIZATION NODE".
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local node is NODE(TIME:SECONDS + ETA:APOAPSIS, 0, 0, 0).
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add node.
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// Calculate required velocity to acheive orbit at altitude equal to apoapsis
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// https://en.wikipedia.org/wiki/Orbital_speed#Mean_orbital_speed
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local orbital_speed is SQRT((CONSTANT:G * ORBIT:BODY:MASS) / (ORBIT:BODY:RADIUS + APOAPSIS)).
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// Calculate the difference between the required velocity and our velocity at apoapsis
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set node:PROGRADE to orbital_speed - VELOCITYAT(SHIP, TIME:SECONDS + ETA:APOAPSIS):ORBIT:MAG.
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}
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function create_orbitchange_node {
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function change_slash_set_orbit {
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parameter what.
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}
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57
util.ks
57
util.ks
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@ -1,11 +1,64 @@
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function warp_to {
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parameter timestamp.
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KUNIVERSE:TIMEWARP:WARPTO(timestamp). // todo: improve.
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KUNIVERSE:TIMEWARP:WARPTO(timestamp). // TODO: improve.
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// wait until TIME >= timestamp. // TODO
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}
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function warp_for {
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parameter seconds.
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return warp_to(TIME:SECONDS + seconds).
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}
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function isp_sum {
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local sum is 0.
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list ENGINES in engines_list.
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for engine in engines_list {
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if engine:STAGE = STAGE:NUMBER set sum to sum + engine:VACUUMISP.
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}
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return sum.
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}
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function round_towards_zero {
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parameter n.
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if n < 0 return CEILING(n).
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return FLOOR(n).
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}
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function orbital_velocity {
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// Calculate the required velocity to acheive orbit at the provided altitude.
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// https://en.wikipedia.org/wiki/Orbital_speed#Mean_orbital_speed
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// http://www.orbiterwiki.org/wiki/Front_Cover_Equations
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parameter altitude.
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return SQRT(BODY:MU / (BODY:RADIUS + altitude)). // BODY:MU = CONSTANT:G * BODY:MASS
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}
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function unlock_control {
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// Ensure that the throttle will be 0 when execution stops
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set SHIP:CONTROL:PILOTMAINTHROTTLE to 0.
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// Ensure that the player is not locked out of control.
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set SHIP:CONTROL:NEUTRALIZE to true.
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unlock STEERING.
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unlock THROTTLE.
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}
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function disable_engine_gimbal {
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// Disable engine gimbal when engine is off
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on (THROTTLE = 0) {
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list ENGINES in engines_list.
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for engine in engines_list {
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if engine:HASGIMBAL set engine:GIMBAL:LOCK to (not THROTTLE).
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}
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return true. // preserve trigger
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}
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}
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