Presets
Playback
Driving, load and ground
Drive with the throttle, steering and brake. The tip angle is atan(half-track / centre-of-mass height); a high or off-centre load lowers it. The tyres can only supply a total force mu N, shared between driving and cornering (the friction circle).
Options
Model checks
The science
What is modelled
A yard truck as a planar vehicle with a bicycle-model turn, an electric motor with a torque curve, rolling and air resistance, a friction-circle grip limit, and a roll degree of freedom that follows lateral acceleration and slope. Suspension corners are springs and dampers driven by gravel bumps.
Equations
- Tip angle:
tan(thetatip) = t / hcgwith the half-track reduced by the load offset. - Friction circle:
Fdrive ≤ sqrt((mu N)2 - Flat2),Flat = m v2 kappa. - Steering:
kappa = tan(0.48 delta) / L. - Braking:
d = v2 / (2 a). - Motor:
P = T omega, peak torque at 70% of maximum speed.
Checks run in the page
- Static tip angle.
- Braking distance against v squared over 2a.
- Friction-circle sharing between driving and cornering.
- Motor torque curve against the rated power.
- Path curvature in a steady turn.
Honest simplifications
Planar bicycle model, a lumped roll response, no tyre slip dynamics, a fixed 2.25 m wheelbase, a speed governor and a simple load model. Illustrative, not a safety certification of any truck.
What to try
- Press Heavy and high and turn: the roll angle approaches the tip limit and the truck turns red.
- Press Wet gravel slope and brake hard: the grip limit lengthens the stop.
- Raise the mast with a heavy pallet: the static tip angle curve shifts down.