Virtual Road Load Data Acquisition for Twist Axle Rear Suspension

The twist axle has highly complicated load paths because of its multiple functions of suspension components. This nature of the twist axle suspension makes the fixed reacted multi-axial suspension test more sophisticated than for other independent suspensions. GM has used Virtual Road Load Data Acquisition (vRLDA) for laboratory tests in the past, but this is the first application of vRLDA for a twist axle multi-axial suspension durability test. In order to utilize vRLDA data for the test input, a new approach to 8 channel multi-axial suspension durability test development was proposed for a twist axle rear suspension.

vRLDA for a GM vehicle with twist axle rear suspension was performed and briefly discussed. Instead of using strain data from the twist axle for correlation channels, inboard channels such as shock tower vertical and trailing arm forces were used in the test development. Emphasis was placed on a high level of correlation for the inboard channels, while the correlation at the WFT (Wheel Force Transducer) channels was secondary. The test development results using the proposed approach were compared with strain data from a physical RLDA. The proposed test development responses showed good correlation with RLDA data. The test of the twist axle has been successfully executed.