Gravel Survey Rover

2D twin of the 3D rover lab: drive force, tyre grip, slope, drag and the cargo-dependent tip angle, driven by the identical physics file.

Presets

Playback

Terrain, drive and load

Speeds in m/s, masses in kg. Grip caps the longitudinal force at 0.92 mu N, so climbing needs the friction to exceed the slope plus rolling resistance. A raised or shifted cargo lifts the centre of mass and lowers the static tip angle atan(track / 2h).

Weather

Model checks

The science

What is modelled

A point-mass rover moving along the slope. Motor force is limited by motor power and torque, opposed by gravity along the slope, air drag and rolling resistance, and capped by the tyre-ground friction. A bicycle steering model gives the lateral acceleration in a turn, and the combined centre of mass of chassis and cargo gives the static tip angle.

Equations

  • m a = Fdrive - m g sinθ - ½ ρ CdA v|v| - crr m g cosθ, with |m a| ≤ 0.92 μ m g cosθ.
  • Tip angle: atan(track / 2h), with h the centre-of-mass height.
  • Cornering: alat = v² tanδ / L.

Checks run in the page

  • Terminal speed against an independent bisection.
  • Grip-limited slide on a steep, slippery slope.
  • Tip angle at 45 and 30 degrees.
  • Heading change in a steady turn.

Honest simplifications

A single-track point-mass model, constant gravel friction, a simple motor curve, a decorative suspension ripple and a static tip estimate that ignores dynamic load transfer. Not a vehicle-safety calculation.

What to try
  • Tick Rain on the gravel and see the rover lose its grip on the slope.
  • Press Steep and loaded: the climb is limited by motor power and grip.
  • Press Fast tight turn and watch the stability margin fall as cargo is shifted up.
Speed
Stability margin against tipping
Cornering tilt and static tip angle
Energy used by the motor
Made with 🤖 ChatGPT