Adams Assignments – Problem 4 – Steering geometry 2

Models : Front SLA (created from Acar library)

Perform kingpin geometry optimization to achieve the following targets

Targets

Caster_angle = 4deg
Caster_MA = 21mm
KPI_angle = 13deg
Steer_axisOffset_off = 85mm
Steer_axisOffset_lon = 0mm
Scrub radius = 20mm

The model used was Double wishbone suspension.

Baseline parameter results are as below :
Parallel wheel travel analysis: Bump 50mm & Rebound -50mm

Caster_angle = 5.4deg
Caster_MA = 8mm
KPI_angle = 10.2deg
Steer_axisOffset_off = 85.7mm
Steer_axisOffset_lon = -18.7mm
Scrub radius =37.25mm

Hardpoint changes :

Steering2_1 Iteration1
UCA outer x value = 40mm to 35mm
LCA outer x value = 0mm to 5mm
LCA outer y value = -750mm to -755mm
UCA outer y value = -675mm to -672.5 mm

Steering2_2 Iteration2
UCA outer x value = 35mm to 30mm
LCA outer x value = 5mm to 2mm
LCA outer y value = -755mm to -760mm
UCA outer y value = -672.5mm to -665mm

Steering2_3 Iteration3
UCA outer x value = 35mm to 30mm
LCA outer x value = 5mm to 1.68mm
LCA outer y value = -755mm to -758mm
UCA outer y value = -672.5mm to -658mm

After the Hardpoint modifications, the co-ordinates obtained are as below:

Graph of the suspension parameters is as below :

Caster Angle (5.5 deg to 4deg)

Caster Moment arm ( 8.5mm to 16mm which near to 13mm)

KPI (10.2 deg to 13deg)

Steer Axis offset resultant (Near 85mm ~86.7mm)

Steer Axis offset longitudinally ( From -18mm to 0mm)

Scrub Radius (38mm to 23.5mm)ut

The parameters are interdependent. If we change one or multiple parameters it will change suspension parameters other than the directly intended parameter.

In this case, the upper control arm and Lower control arm outer ball joint X and Y coordinates are varied to get the required target values.

The baseline scrub radius reduction is done with UCA and LCA outer ball joint Y-coordinate. But the steering offset & KPI changed simultaneously.

Thus, some of the parameters are highly interdependent.

Drive Link

https://drive.google.com/file/d/1HRLwIHOSnfka34OoJZA5roq8bjq5oEWD/view?usp=sharing