oyster_catcher
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Posts posted by oyster_catcher
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Thanks. The landing burn should say "too heavy" if have insufficient thrust, and it looks like you have sufficient thrust, but its applied too late. Also go to Advanced and increase "touchdown margin" by 10m. The vessel should think the ground is higher and slow down earlier above the ground. It should then descend at "touchdown speed" of 2m/s default. Looking at your video it definitely looks like increasing "touchdown margin" should help.
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Thanks. Yes I'm testing on KSP 1.11 too. So you are saying you set the target then revert to launch, and the target is lost when you revert? Unfortunately this probably expected behaviour if you are reverting to before you set the target. What is you save the game and then continue from the saved game? I hope that should save the target. Be glad to see your video.
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Hi @TheKurganThanks for the kind words. In version 1.0.3 the target should be saved with the vessel and in saved games, but only if ModuleManager is installed. (I need to add an check for that) So if you find the target isn't persistent and you have ModuleManager installed please send me some details on when it happens as I'd like to fix it. Thanks
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@TheKurganYes I should think I could add triggering by an action group. Perhaps then I could be triggered immediately on staging. I've seen a bit of this part of the API but I'm not familiar without so I'll need to work it out. The best bet is probably for me to look at the MechJeb code so thanks for that tip.
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Ok, thanks I will remove Module Manager. Version 1.0.3a is now without ModuleManager at https://spacedock.info/mod/2587/BoosterGuidance and https://github.com/oyster-catcher/BoosterGuidance
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Version 1.0.3 released
I've been working on controlling multiple vessels simultaneously with BoosterGuidance, v1.0.2 did do this but I've fixed a lots of bugs that come up with multiple vessels and now the BoosterGuidance settings can be saved with craft and with saved games. To prove it all works I've achieved a double simultaneous return and landing of two boosters from space. It looks a while for me to work out about physics bubbles. When it the atmosphere all controlled vessels must be inside the 20km physics bubble and even then you may not be able to switch vessels. My video shows how you can do the dual booster landing with the latest version of BoosterGuidance and the SpaceX Launch Vehicles mod for the SpaceX parts. I also show how to construct a Falcon Heavy but this is my first craft construction tutorial and as luck goes a number of expected problems came up, but it worked in the end! Enjoy.
Changes in 1.0.3:
Improvements for controlling multiple vessels simultaneously
- Lots of bug fixes when switching vessels, e.g. show correct target, use correct settings
- Add settings module which means settings are saved (e.g. target, re-entry alt, etc...) with the vessel in saved games. Will even save enable/disable guidance and phase so quick saves continue with vessels still controlled
- Advanced menu can show brief info about other controlled vessels
- Bug fix to ensure target is updated for vessel
- Added ModuleManager DLL as Command Modules are patched to add BoosterGuidanceVesselSettings module
- Reports message to user when vessels go outside the 20km physics bubble and can no longer be controlled due to game limitationhttps://github.com/oyster-catcher/BoosterGuidance/releases/tag/1.0.3
or
https://spacedock.info/mod/2587/BoosterGuidance
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Version 1.0.2 released
- Major improvements to pick targets. You can now pick a target anywhere in the flight or map view!
- Increased default touchdown margin for safety as some rockets were reported crashing into the ground
- Landing burn compensates for leaned over rockets by using extra thrust
- Can now set target to navigation waypoints (note that they are currently sticky and you can't edit the lat/lon/alt until waypoint is deactivated)
- Landing on Mun better working but sometimes timewarp seems to move vessel oddly and throw out predictions (very odd)
- Can now edit lat/lon with arrow adjusters so you can now fly back multiple cores and ensure they don't land on each other!Released under GPL v3.
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@jrolson Ok thats odd. The boostback burn is key. Perhaps it is switching to aero descent before the boostback burn has brought the red predicted target onto the yellow desired target. It can also switch out of boostback if in the atmosphere and the target error seems to be increasing, which can happen if the craft is not able to point in the right direction. If so you can re-trigger boostback. Take a look at my latest video
which may help
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Thanks @computercat04. Doh! It was still a private repo. It should work now its public.
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This may not be new but here's my mod which aims to autonomously guide a Booster to land on a drone ship or the launch site (or anywhere else) using a combination of Boostback, Re-entry Burn, Aerodynamic Descent and Landing Burn, i.e. SpaceX Falcon 9 style. Select your landing point either by clicking on it, typing the latitude+longitude+altitude or selecting a target (e.g. drone ship). Its aimed to be reliable and fairly easy to use. I've also made it work in Realism Overhaul where limited throttle able engines and limited ignitions mean you can't play fast and lose with your engines. With suitable engines and using the right number active you can achieve this is Realism Overhaul which gives a real feeling of satisfaction.
The mod relies on accurately simulating the entire trajectory to landing including burns later in the flight which means guidance should be accurate without the need for any heroic manoeuvres as the impact of say the reentry burn is properly factored in. BoosterGuidance will continuously monitor the target error and aim to reduce it in boostback, re-entry burn, aerodynamic descent and in the landing burn steering either via engines or via grid-fins depending on the phase of flight. You can set the steering gains during the flight to give the grid fins more/less to do, and configure the reentry burn via altitude and target velocity. Some more advanced settings allow you to set safety margins, speed of final descent, at what height to give up steering and more. You can also log the whole flight and plot it to examine in detail what happened and how closely you could copy SpaceX.
Released under GLP v3.
Here's some videos showing it working with a single stage Falcon 9 booster
In Realism Overhaul with a 2-stage Falcon 9 rocket where I make a half-hearted attempt to get the 2nd-stage to orbit.
This mod is very usable and lots of fun now but has a few limitations I'm working on.
- Clicking the target only works close to the terrain or there are physical structure (some KSP/Unity Raycast limitation I don't understand)
- In Realism Overhaul you may need to manually reduce the gain close to landing to avoid large oscillations
- Landing legs deployment is unreliable
- Guiding more than one booster simultaneously should be possible but is currently unreliable. My goal is a Falcon Heavy two booster landing. That will be awesome!
- It should work on other planets too though the trajectory should be sub-orbital to impact the ground within about 10 minutes as simulation time is limited for CPU reasons
Get the mod via GitHub here: https://github.com/oyster-catcher/BoosterGuidance/releases
or on SpaceDock here: https://spacedock.info/mod/2587/BoosterGuidance
Released under GPL v3
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I've been working on a mod to reliably boostback and land boosters Falcon 9 style. The aim is for very high accuracy, reliability, easy to use. Its nearly there. I've posted a video of it working in base KSP and will shortly upload a Realism Overhaul example.
Please enjoy. I hope to release the mod within a week or two after adding automatic deployment or grid fins and landing gear.
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I've been trying to emulate Falcon 9 landings and finally the SN8 Starship skydive manoeuvre with Realism Overhaul. I'm using the StarShip Cargo model from EDB Mods (Raiz Aerospace) plus some B9 Procedural wings fitted sideways! so I can emulate the movement of the starship control surfaces. With the procedural wings controls I can make the control surfaces acts of airbrakes differentially fore and aft to change pitch in the skydive, unfortunately setting them to work differentially both left/right and fore/aft to change yaw doesn't seem to have much effect. Anyway I can achieve a stable descent and forwards and backwards movement.
I'm using the trajectories mod to steer going up and in aerodynamic descent than I use my mod, HopperGuidance to do the flip and the final landing. I got it to work after numerous tries. Enjoy
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I'm try to find the ISP of an engine from the class ModuleEngines https://kerbalspaceprogram.com/api/class_module_engines.html for use in my mod HopperGuidance. Its a pretty complex class!
In the base game I can use engine.realIsp to give me the ISP at the current atmospheric density. It works whether the engine is throttled up/activated or not. I can then use
minThrust = engine.GetEngineThrust(engine.realIsp, 0)
maxThrust = engine.GetEngineThrust(engine.realIsp, 0)
But in RO engine.realIsp=0 until the engine is ignited. I've rather let HopperGuidance decide when to activate the engine as it is much better as working this out than my guesses. So I want to enquire about min/max thrust BEFORE deciding to fire up the engine.
I tried:
isp = engine.atmCurveIsp.Evaluate(atm) but this gives isp=0 probably because useAtmCurveIsp=false on the Raptor engine I'm looking at even through the config from "Launchers Pack/Rockets/SpaceX_ITS/KK_Raptor/KK_Raptor.cfg" has
atmosphereCurve
{
key = 0 335
key = 1 280
key = 5 0.001
}which is a shame as it looks like it should be easy to find the ISP from this curve. Is them some other factor I'm missing, there are no end of multipliers, factors and curves in this module.
thanks
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Sorry. I messed up with this new thread. I've now managed to change the title on the original. So the versioning isn't confusing. Please use this thread.
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fixed up the title now.
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New release version 0.2.3.
This version is a major improvement. See the video I had a lot of fun making below. Now works much better in the base game and with Realism Overhaul. The major change is the picking of intermediate targets above ground which means you can now define a full trajectory to fly under bridge, simulate an SN5 hop or land a falcon 9 booster (the later two in Realism Overhaul). Its computes better trajectories faster and more reliably and now works well on other planets with different gravity from Kerbin/Earth.
- Added ability to pick multiple intermediate targets
- Removed latitude, longitude and altitude target (set target via pick target only)
- Removed max landing thrust angle, it is set to 10% of max thrust angle
- Removed acceleration gain, it is set to 4x correction factor
- Removed idle angle, it is now always 90 degrees
- Removed max thrust, this is set to 90% of the vessels maximum
- Max thrust angle in the solution is 80% of max thrust angle (allowing 20% extra for corrections)
- Min descent angle only applies to the final trajectory before the final target and not to intermediate targets
- Ground intersect constraint always applies where the ground is the lowest of all the ground targets
- The solution velocity isn't modified by the PID, which results in better following of the trajectory
- Switch to using mesh rather than LineRenderer for track and thrust vectors as transformations work better
- Golden search over time now falls back to simpler search stepping through 10 intervals between Tmin and Tmax then continues golden search, as golden search fails when probe points are non-solutions. This results in much better and faster solutions
- Fixed disappearing track bug when active for a long timeDownload v0.2.3 from https://github.com/oyster-catcher/HopperGuidance
Install by unpacking HopperGuidance-v0.2.3.zip into your KSP GameData folder.
NOTE: Second thread about this mod in order to fix up the wrong versioning convention in the title which caused some confusion. Sorry about that.
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Sorry about the confusion in the versioning. The mod version is v0.2.3 but it works with KSP 1.8.1 up to KSP 1.10.1. I'm still learning about how to do it right. I'll fix it u once I've worked out the right conventions
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New release version 0.2.3.
This version is a major improvement. See the video I had a lot of fun making below. Now works much better in the base game and with Realism Overhaul. The a major change is the picking of intermediate targets above ground which means you can now define a full trajectory to fly under bridge, simulate an SN5 hop and land a falcon 9 booster (the later two in Realism Overhaul). Its computes better trajectories faster and more reliably and now works well on other planets with different gravity from Kerbin/Earth.
- Added ability to pick multiple intermediate targets
- Removed latitude, longitude and altitude target (set target via pick target only)
- Removed max landing thrust angle, it is set to 10% of max thrust angle
- Removed acceleration gain, it is set to 4x correction factor
- Removed idle angle, it is now always 90 degrees
- Removed max thrust, this is set to 90% of the vessels maximum
- Max thrust angle in the solution is 80% of max thrust angle (allowing 20% extra for corrections)
- Min descent angle only applies to the final trajectory before the final target and not to intermediate targets
- Ground intersect constraint always applies where the ground is the lowest of all the ground targets
- The solution velocity isn't modified by the PID, which results in better following of the trajectory
- Switch to using mesh rather than LineRenderer for track and thrust vectors as transformations work better
- Golden search over time now falls back to simpler search stepping through 10 intervals between Tmin and Tmax then continues golden search, as golden search fails when probe points are non-solutions. This results in much better and faster solutions
- Fixed disappearing track bug when active for a long timeDownload v0.2.3 from https://github.com/oyster-catcher/HopperGuidance
Licensed with GPL v2.
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I'm please to announce the release of my first KSP mod HopperGuidance. I initially wrote this 2 years ago in Python using kRPC. I've now re-written it completely in C#, so its closely integrated with KSP and its 10x better because of it. Extract from README at https://github.com/oyster-catcher/HopperGuidance
HopperGuidance
==============A KSP mod which enables the calculation of a fuel efficient trajectory in-flight to make a soft landing at a designated location respecting the capabilities of the craft. The craft will be steered automonously to follow this trajectory. You can choose many parameters of the trajectory to make it safe or more exciting.
Features
- Choose a landing latitude, longitude and altitude
- Shows the trajectory to landing and require thrust vectors
- Lets you tune the parameters to the craftYou can choose a particular latitude and longitude and altitude to land at, although currently this works best close to the landing site such as within 10km. It must take less than 5 minutes to land. It certainly can't handle descent from orbit and it treats the planet surface as flat and doesn't take into account atmospheric drag, though can correct for it while flying. It may waste quite a bit of fuel trying to keep to the pre-calculated trajectory too. You can give it a try though, its all good fun.
The algorithm used is aimed to be an implementation of the G-FOLD algorithm for fuel optimal diverts
reputably used by Lars Blackmore for landing the SpaceX Falcon-9 rocket. However my algorithm is a simplified version of it and I've added some of my own constraints. See later.Please see the video https://www.youtube.com/watch?v=Ekywp-P6EBQ&t=301
References
- "G-FOLD: A Real-Time Implementable Fuel Optimal Large Divert Guidance Algorithm for Planetary Pinpoint Landing" https://www.researchgate.net/publication/258676350_G-FOLD_A_Real-Time_Implementable_Fuel_Optimal_Large_Divert_Guidance_Algorithm_for_Planetary_Pinpoint_Landing.
- "Convex Programming Approach to Powered Descent Guidance for Mars Landing" https://arc.aiaa.org/doi/abs/10.2514/1.27553
- "Minimum-Landing-Error Powered-Descent Guidance for Mars Landing Using Convex Optimization" http://www.larsblackmore.com/BlackmoreEtAlJGCD10.pdf
Prerequistes
============Works with KSP versions 1.8.1 to 1.10 and possibly beyond.
If you want to run the solver outside of KSP you need python and matplotlib to show the trajectories.Installing
==========Copy GameData on top of the existing GameData folder in your KSP installation.
Licensed under GPL v2.
Includes ALGLIB (ALGLIB.net) also licensed under GPL v2.
Much for info in the README included with the mod.
Adrian Skilling
Please try it out from https://github.com/oyster-catcher/HopperGuidance. Please let me know if any problems. I'll be happy to try and fix them, Adrian. Fly safe!
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I'd like to announce a project I've been working on for some time to implement a simplified version of the G-FOLD automated soft-landing algorithm using the KRPC plugin, and the cvxopt convex optimisation library, all pretty dry sounding, OK, so what does it do? Well take a smallish fairly manoeuvrable craft, steer around a bit wildly (near the landing) spot, activate the soft-landing algorithm and it calculates a trajectory (shown visually) and thrust directions with minimum fuel use, and then auto-pilots the craft along the trajectory to land it craft anywhere you specify. Its been a lot of fun tweaking it to work reliably, it can now do some pretty dramatic recoveries.
Heres a video that explains it better.
Automated soft-landing montage video
I've a much more detailed description here plus more videos including the crashes, and the python code is available here.
[1.8.1 - 1.10.1] BoostGuidance v1.0.1
in KSP1 Mod Releases
Posted
Excellent. So pleased! I'll see if can avoid needing such a tweak factor in future versions. I found it particularly necessary to have touchdown margin a bit higher in Realism Overhaul as the delays in throttling up the engine mean the suicide burn can be late, but thats no excuse in stock KSP.