eu07/maszyna
17
0
Fork 0
mirror of https://github.com/MaSzyna-EU07/maszyna.git synced 2026-11-07 19:14:46 +01:00
Code Issues 147 Wiki Activity

fix(physics): articulated couplers stall freight trains (eu07/maszyna#553) (#255)

Browse Source 
* fix(physics): articulated couplers stall freight trains (eu07/maszyna#553)

Articulated wagons (T3000e, N-230, N-234) set up with CType=Articulated
barely moved in a freight train and jerked.

- The articulated joint took the spring force up to DmaxC = 0.05 m only,
  225 kN, well short of its FmaxC of 850 kN and of what a loaded section
  in a freight train takes. It overstretched and the sections collided at
  every physics step. Dmax is now sized so the spring carries FmaxC
  (0.19 m stretched, 0.09 m pressed in), never below the old 0.05 m.
- ComputeCollision() scaled the velocities of both vehicles by
  sqrt(1 - beta), so each collision braked the pair as a whole: two
  coupled vehicles in a sustained "collision" lost a third of their speed
  per step. The restitution now applies to the velocities relative to the
  centre of mass only, and the pair keeps its momentum.

Tests: the articulated joint carries FmaxC within its travel; a jerked
articulated set and a jerked screw-coupled pair keep their momentum. On
the code before the fix both pairs stop dead within 3 s.

* style(physics): English-only comment in ComputeCollision()

The comment above the collision velocities started in Polish and went on in English.

* style(physics): SonarQube findings in the #553 fix

std::lerp for the collision velocities (cpp:S6179) and test locals renamed so they no longer shadow the end and coupling enumerators (cpp:S1117).
This commit is contained in:
pawelw
2026-11-05 10:25:26 +01:00
committed by GitHub
parent 09b1c2de10
commit fc22645d7c
2 changed files with 82 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
McZapkie/Mover.cpp
View File

@@ -17,6 +17,7 @@ http://mozilla.org/MPL/2.0/.
#include "utilities/parser.h"
#include "simulation/simulation.h"
#include <cmath>
#include <format>
//---------------------------------------------------------------------------
@@ -51,8 +52,13 @@ double ComputeCollision(double &v1, double &v2, double m1, double m2, double bet
double sum = m1 + m2;
double w1 = (m2 * v2 * 2.0 + v1 * (m1 - m2)) / sum;
double w2 = (m1 * v1 * 2.0 + v2 * (m2 - m1)) / sum;
v1 = w1 * std::sqrt(1.0 - beta); // niejawna zmiana predkosci wskutek zderzenia
v2 = w2 * std::sqrt(1.0 - beta);
// the collision changes the velocities directly: the bounce loses energy in the velocities relative to the
// centre of mass only, the pair keeps its momentum. scaling the velocities themselves braked the vehicles
// down with every step their couplers spent stretched or pressed in all the way (eu07/maszyna#553)
auto const centre{(m1 * v1 + m2 * v2) / sum};
auto const restitution{std::sqrt(1.0 - beta)};
v1 = std::lerp(centre, w1, restitution);
v2 = std::lerp(centre, w2, restitution);
return m1 * (w2 - w1) * (1 - beta);
}
}
@@ -10695,12 +10701,15 @@ void TMoverParameters::LoadFIZ_BuffCoupl(std::string const &line, int const Inde
coupler->beta = 0.55;
*/
thiscoupler->SpringKC = 4500 * 1000;
thiscoupler->DmaxC = 0.05;
thiscoupler->FmaxC = 850 * 1000;
thiscoupler->SpringKB = 9200 * 1000;
thiscoupler->DmaxB = 0.05;
thiscoupler->FmaxB = 320 * 1000;
thiscoupler->beta = 0.55;
// the spring force is taken up to Dmax only, past it the vehicles collide (CollisionDetect()); so the joint
// carries the full FmaxC either way before it gives. with 0.05 m it carried 225 kN, short of what a loaded
// articulated wagon in a freight train takes, which then collided at every step (eu07/maszyna#553)
thiscoupler->DmaxC = std::max(0.05, thiscoupler->FmaxC / thiscoupler->SpringKC);
thiscoupler->DmaxB = std::max(0.05, thiscoupler->FmaxC / thiscoupler->SpringKB);
}
if (Index == 0)