ModelSim Lab
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System libraryMechanical

Quarter-Car Suspension

ORDER 4 · INTERMEDIATE

Explore the tradeoff between body comfort, suspension travel and tire deflection.

Physical system

PHYSICAL SYSTEMSI units · schematic scale
Sprung mass 300 kgroad r(t)Body acceleration 0 m/s²
Motion follows the computed statest = 0 s
msz¨s=−ks(zs−zu)−cs(z˙s−z˙u),muz¨u=ks(zs−zu)+cs(z˙s−z˙u)−kt(zu−r)−ct(z˙u−r˙)m_s\ddot z_s=-k_s(z_s-z_u)-c_s(\dot z_s-\dot z_u),\quad m_u\ddot z_u=k_s(z_s-z_u)+c_s(\dot z_s-\dot z_u)-k_t(z_u-r)-c_t(\dot z_u-\dot r)
0.00 / 8 s
Output sampling refined to 0.00200 s to resolve the fastest dynamics and preserve measured peaks.

Body displacement response

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4001 samples. Primary output ends at -4.06e-6 m. Export CSV for all data.
0.01231 m
0 m
0.06143 m
-4.06e-6 m
4.092 s
Not applicable
Not observed
1.406 s

4,001 samples · 8,000 internal RK4 steps · Model and result in sync