Adjust double wishbone or MacPherson strut geometry in real time and visualize camber angle, track width change, and roll center height vs wheel travel.
The core of suspension kinematics is analyzing the rigid body motion of the wheel assembly, connected by two control arms (for a double wishbone) or a strut and a control arm. The position of the wheel center is determined by the intersection of spheres defined by the arm lengths.
$$ \vec{P}_{wheel}= \vec{P}_{upper}+ L_{u}\hat{u}= \vec{P}_{lower}+ L_{l}\hat{l}$$Where $\vec{P}_{wheel}$ is the wheel center point, $\vec{P}_{upper}$ and $\vec{P}_{lower}$ are the inner pivot points on the chassis, $L_u$ and $L_l$ are the upper and lower arm lengths, and $\hat{u}$ and $\hat{l}$ are the unit vectors along the arms. Solving this constraint gives the wheel's position for any given suspension travel.
Camber angle $\gamma$ is a direct output of this solved geometry. It's the inclination of the wheel plane from the vertical. The instantaneous roll center is found geometrically by intersecting lines through the instant centers of the control arms.
$$ \gamma = \arctan\left(\frac{\Delta y}{\Delta z}\right) $$Here, $\Delta y$ and $\Delta z$ are the lateral and vertical displacements of the top and bottom of the wheel. A negative $\gamma$ during compression (top tilting in) is often desirable for maintaining tire contact during cornering body roll.
Performance Vehicle Tuning: Race engineers obsess over kinematics. They adjust pickup points on the chassis to fine-tune camber gain, ensuring the tire remains flat on the track during high-G corners for maximum grip. The simulator's "Arm Length" sliders directly mimic this tuning process.
Off-Road & SUV Development: For vehicles that need massive wheel travel, kinematics ensures the tire doesn't tuck in too far or hit the fender. A key goal is managing the drastic change in track width, which you can visualize with the "Track Width Change" plot in the tool.
Electric Vehicle Packaging: EVs often have a flat battery pack in the floor. Suspension geometry must be designed around this hard point to achieve desired kinematics without compromising ground clearance or battery safety, making virtual simulators like this essential.
Brake System Integration: As mentioned in the FAQ, scrub radius is critical. Engineers use kinematic models to minimize brake steer, where uneven braking forces cause unwanted steering pull. This is vital for safety and driver confidence in all modern cars.
First, understand that "good values" change depending on the situation. For example, aiming for camber change to be close to "zero" is not always the correct answer. Racing cars are designed to achieve strong negative camber during bounce to pursue ultimate cornering performance. Conversely, for general passenger cars, the amount of change is kept small to prevent uneven tire wear. Before trying to draw an "ideal curve" in the simulator, first consider "what is the intended use of this vehicle?"
Next, there is the pitfall that parameters are not independent. Changing the length of the upper arm will change the camber curve, but it will also move the roll center height simultaneously. For instance, if you lengthen the upper arm by 10mm to improve camber characteristics, the roll center might rise by 5mm, potentially causing other effects on handling stability. In practice, it's a battle against these trade-offs. When you adjust one parameter, make it a habit to always check all other outputs.
Finally, don't forget that the simulation calculates for "ideal rigid bodies". Actual suspensions have bush compliance, arm stiffness, and even deformation of the tire itself under load. Even if you achieve perfect characteristics in the simulator, if real-world testing shows "more roll than expected," you need to suspect the influence of bush compliance (flexibility). Remember, this tool is the first step in determining the "geometric skeleton," followed by CAE analysis that considers component elasticity.
Double wishbone sedan suspension: upper arm 320 mm, lower arm 380 mm, upper mount offset 85 mm from wheel center. At 0 mm ride height, camber reads -0.2°; at +50 mm jounce (compression), camber drops to -1.8° with roll center height rising 12 mm. Track width increases 3.2 mm over 100 mm travel. With 12 kN vertical load applied, anti-dive geometry yields 15% anti-dive, reducing front-end dive under braking from nominal 45 mm to 38 mm over 1 m stopping distance.