Vehicle Ride and Handling Analysis - Maple Help



Vehicle Ride and Handling Analysis

Introduction

This tool lets you experiment with the steer- and camber-by-roll coefficients of a 3-DOF vehicle model, and simulate the effect on the yaw gain curve and the understeer coefficient. To use this tool, do the following:

 • Enter the vehicle mass, inertial, geometric and compliance properties, then the natural-frequency requirements for the suspension.
 • Click Compute Parameters to determine the stiffness and damping coefficients.
 • Adjust Steer-by-Roll and Camber-by-Roll factors.
 • Set up simulation properties and click  Run Simulation.

Mass and Inertia

Geometry

 Vehicle curb weight $\mathrm{kg}$ Total vehicle sprung mass weight $\mathrm{kg}$ Unsprung weight per wheel, front $\mathrm{kg}$ Unsprung weight per wheel, rear $\mathrm{kg}$ Vehicle inertia about z axis $\mathrm{kg}\cdot {\mathrm{m}}^{2}$ Sprung mass inertial about x axis

 Wheel base $\mathrm{m}$ Track ( front and rear) $\mathrm{m}$ Distance of CG from front axle (a) $\mathrm{m}$ Distance of CG from rear axle (b) $\mathrm{m}$ Vehicle CG height $\mathrm{m}$ Sprung mass CG height $\mathrm{m}$ Roll center height ( front/rear) $\mathrm{m}$

Compliances

Requirements

 Tire cornering stiffness (front and rear)  Tire vertical stiffness Tire camber stiffness (front and rear) Front shock absorber rate ( per wheel) Rear shock absorber rate ( per wheel) Distance between installation point of left and right springs (front and rear): $\mathrm{m}$ Distance between installation point of left and right shock absorber (front and rear): $\mathrm{m}$ Installation factor for springs and shock absorbers for front and rear wheels $\mathrm{m}$

 First natural frequency of front suspension $\mathrm{Hz}$              $\mathrm{rad}\cdot {\mathrm{s}}^{-1}$ First natural frequency of rear suspension $\mathrm{Hz}$              $\mathrm{rad}\cdot {\mathrm{s}}^{-1}$ Anti-roll-bar on front axle, Roll Gain

Calculated Parameters

Understeer/Oversteer

 Front Suspension Stiffness, $\mathrm{k__sF}$ Rear Suspension Stiffness, $\mathrm{k__sR}$ Overall Torsional Stiffness, $\mathrm{K__t}$ Overall Torsional Damping, $\mathrm{C__t}$ Anti Roll-Bar Torsional Stiffness, $\mathrm{K__ARB}$

 ${\mathrm{K}}_{\mathrm{SBRF}}$ ${\mathrm{K}}_{\mathrm{SBRR}}$ ${\mathrm{K}}_{\mathrm{CBRF}}$ ${\mathrm{K}}_{\mathrm{CBRR}}$

Simulation Setup

 Vehicle Speed = Steering Angle deg Simulation Duration seconds

Results