RCS Thruster Optimisation

This solution explores attitude/translation control for reaction control systems (RCS) with multiple thrusters. It focuses on mapping a desired force/torque command to per‑thruster power levels bounded to [0,1], and compares two solver implementations.

NuGet Packages

Latest: Unified Package (v2.0.0+)

As of v2.0.0, all core projects are consolidated into a single RCS NuGet package supporting .NET Framework 4.7.1 and higher:

<PackageReference Include="RCS" Version="2.0.0" />

Supported Frameworks:

• .NET Framework 4.7.1
• .NET Framework 4.7.2
• .NET Framework 4.8

This single package includes:

• LinearSolver – solver interfaces and utilities
• LinearSolver.Custom.GoalProgramming – goal programming solver implementation
• RCS – core domain types and engine optimizer

Breaking Change: Previous separate packages (LinearSolver v1.0.0, LinearSolver.Custom v1.0.0) are no longer published. See Migration Guide below.

Solver-Specific Packages (Optional)

• RCS.MSF – Uses Microsoft Solver Foundation (separate package, requires additional setup)

Projects

• RCS – core domain types (vectors, thrusters, engine, command) plus the generic RcsEngineOptimiser that builds the coefficient matrix and desired vector from a fleet of thrusters.
• RCS.Custom – optimiser wired to a custom linear solver that searches bounded thrust levels without MSF.
• RCS.MSF – optimiser wired to the Microsoft Solver Foundation goal-based solver (MsfGoalLinearSolver) as the reference implementation.
• LinearSolver – shared solver interface and progress type.
• LinearSolver.Custom.GoalProgramming – goal programming solver implementation (now bundled in RCS v2.0.0+).
• LinearSolver.MSF – MSF-based solver implementation (optional dependency).
• RCS.Test – MSTest suite that validates solver behaviour across several thruster layouts (12 thrusters, 3Fx, 3Opposite, 4Fx) and all force/torque directions, including soft-goal scenarios.

How it works

1. RcsEngineOptimiser orders thrusters, builds a 6×N coefficient matrix (Fx/Fy/Fz/Tx/Ty/Tz rows), and derives desired row targets from an RcsCommand.
2. RcsCommand can request forces/torques and optionally allow non-commanded axes to be treated as soft goals (encoded as double.NaN in the desired vector).
3. The linear solver streams progress snapshots of per‑thruster outputs; the optimiser maps each snapshot to resultant force/torque.
4. Tests assert that the custom and MSF optimisers agree on outputs and resultant vectors for each scenario, across multiple thruster layouts.

Running tests

dotnet test RCS.Test/RCS.Test.csproj

Key scenarios in tests

• Max/Min force and torque in all axes for the 12‑thruster rig.
• Degenerate layouts (3Fx, 4Fx) to probe feasibility and soft-goal handling.
• Soft non-commanded axes (AllowNonCommandedForces / AllowNonCommandedTorques) to allow the solver to prefer, but not require, zero on unrequested axes.

Migration Guide

Upgrading from v1.0.0 to v2.0.0

What Changed:

• LinearSolver and LinearSolver.Custom are no longer published as separate packages
• All solver implementations consolidated into single RCS package
• Framework updated to .NET Framework 4.7.1
• MSF dependency removed from core RCS package

For Consumers Using RCS v1.x:

1. No Action Required: Simply update your package reference:

   <!-- Before -->
   <PackageReference Include="RCS" Version="1.0.0" />
   
   <!-- After -->
   <PackageReference Include="RCS" Version="2.0.0" />

2. All functionality remains the same; the v2.0.0 package is a drop-in replacement

For Consumers Using LinearSolver or LinearSolver.Custom Separately:

1. Remove old references:

   <!-- Remove these -->
   <PackageReference Include="LinearSolver" Version="1.0.0" />
   <PackageReference Include="LinearSolver.Custom" Version="1.0.0" />

2. Replace with unified package:

   <!-- Add this -->
   <PackageReference Include="RCS" Version="2.0.0" />

3. Update usings (if required): Most code should work unchanged since namespaces are preserved:
   • LinearSolver namespace still available
   • LinearSolver.Custom namespace still available
   • RCS namespace still available

Breaking Changes:

• If you directly referenced LinearSolver or LinearSolver.Custom NuGet packages, you must switch to the unified RCS package
• .NET Framework requirement: v4.7.1 or higher (updated from v4.7.2, but still compatible)

No API Changes:

• Class/interface signatures unchanged
• Namespace structure preserved
• All public APIs remain backward compatible
• Just bundled into a single package