upBUS – Electrical, autonomous driving, transmodular bus for public transport systems

Abstract

Worldwide, regions are on the verge of collapse due to the ongoing urbanization and an increasing number of cars. In order to relieve overcrowded streets, the airspace above the ground must be opened for urban mobility. Aircraft taxis are the logical option to develop urban airspace for private transport. However from a long-term perspective, these won't be the solution to the aforementioned traffic congestion problems. In addition to the high energy consumption, aircraft taxis would rather shift individual traffic from the ground level to the airspace. Therefore, only a further development of public transport will be able to solve current and future problems. upBUS offers the solution by combining the development of two different transport systems, urban ropeways and autonomous electric busses. Ropeway systems are an ideal solution to use the airspace above the street level. They are known for their low investment and operating costs, their short construction times without traffic obstruction, minimal space and energy requirements, as well as enormous routing flexibility. On the other hand, ropeways are characterized by the problem of network integration, as the stations cannot be positioned in any necessary place. There are also areas, such as historic towns, which cannot be crossed by ropeways. The upBUS approach is to merge urban ropeways and autonomous mini buses into a modular system. On the ground level the vehicles act as autonomous electric buses. In a ropeway station they transform into a ropeway cabin. This transformation process works fully automatically during operation and passengers do not have to switch between different transportation systems. The upBUS vehicle consists of three parts. The electric drive technology and all sensors for autonomous driving are integrated into a skateboard which acts as the driving unit. The ropeway provides a suspension with a connector plate. The third part, the passenger cabin, can either connect to the driving unit or to the connector plate of the ropeway suspension. Thereby, upBUS benefits from the flexibility of buses in combination with the high passenger throughput of urban ropeways. With the upBUS concept, urban ropeways are not a stand-alone solution any longer and can be easily integrated into the public transportation system. The key technology of this transformation concept can be separated into three parts. First, a specific kind of coupling radar is developed, which provides precise positioning data in order to align the bus with the ropeway suspension. If the parts are aligned within the range of a few centimeters a lifting mechanism in the driving unit hoists the cabin into the suspension. Guiding elements align the two parts within a few millimeters. At this point coupling-interfaces on the roof of the cabin couple with counterparts on the suspension while coupling-interfaces between driving unit and cabin decouple. The cabin leaves the station as a ropeway. The transformation process works vice versa. This paper explains in detail the advantages of this new mobility system and describes the technical parts of the transformation process by designing a first prototype which demonstrates the key-technology in November 2020.