AIRTRANS steering system improvements for operation in an urban application

The successful operation of AIRTRANS at the Dallas/Fort Worth Airport prompted Congress, DOT, and Vought to investigate the extension of this AGT technology into an urban environment. Higher speeds, reduced capital and operating costs, and increased reliability were recommended to deploy AIRTRANS in an urban application. This paper presents the selection of improvements to the steering system necessary for AIRTRANS to demonstrate the above recommendations. A highly instrumented vehicle was used to obtain forces, accelerations and displacements. Evaluation of baseline data, analysis, and design conceived the following steering concepts: • an improved mechanical steering system, • a hydraulic power boosted steering system and • a contactless strip follower steering system. Two design improvements to the meahanical steering system: • a single guide/switchwheel design, • a anti-friction kingpin design, and the three steering concepts are discussed in detail evaluating their merits relative to loads, speed, and ride quality. The improved mechanical system was conceived as the basic candidate for immediate urban application of AIRTRANS, with the power boosted and contactless systems being feasible candidates for higher speeds when they are fully developed. At AIRTRANS design speeds the improved mechanical system reduced the guidebar loads significantly and improved the ride quality. The power boosted and contactless steering systems exhibited ride quality improvements over the baseline vehicle also. However, at higher speeds, 20-30 mph loads increased and ride quality deteriorated for all steering concepts requiring guideway treatments and suspension system improvements. The later is being accomplished in Phase II with the design of a lateral and softer vertical suspension system.