Search Results

This paper describes some methods for greatly reducing or possibly eliminating subjective tuning of suspension parts for ride and handling. Laptop computers can now be used in the vehicle to guide the tuning process. The same tools can be used to select solutions that reduce sensitivity to production and environmental variations. OBJECTIVE Reduce or eliminate time required for tuning of suspension parts for ride characteristics. Improve the robustness of ride performance relative to variations in ambient temperature and production tolerances. PROBLEM REQUIRING SOLUTION AND METHOD OF APPROACH Traditional development programs for new vehicles include time-consuming subjective ride evaluations. One example is shock absorber tuning. Even if sophisticated models define force-velocity curves, numerous hardware iterations are needed to find valvings that will reproduce the curves. Many evaluation rides are needed to modify the valvings to meet performance targets.

The three-dimensional motions of the front and rear wheels of a passenger car have been obtained from “Over-the-Road” tests, with great accuracy (1a RMSE ≊ 0.6mm) using raw data recovered from synchronized video cameras. Data from a variety of tests have been combined and treated to produce maximal tire envelopes. This effort has demonstrated the potential of image-based motion measurement as a product design and development tool. Traditional techniques for recovering tire envelopes are described, and their limitations discussed. Image-based motion measurement is offered as an more accurate alternative. The task-specific constraints which limit the selection of imaging hardware are discussed, and a scientific foundation for the new technique is provided. A series of tests has been conducted to demonstrate the viability of the proposed approach. The procedures used to instrument the vehicle and collect raw video images at highway speeds are described.