Nabtesco continues to expand its activities in the automotive sector. Together with adcos, a company of the Nabtesco Group, the transmission specialist has developed a purely electromechanical steering and drive solution for commercial vehicles, thus setting its sights on the next stage towards autonomous driving. The first prototypes of the innovative steer-by-wire system are being used as functional models in the new urban transport concept SRT (Super Virtual Rail Train) of the Chinese rail vehicle manufacturer CRRC / ZELC.
Six Super Virtual Rail Trains (SRT) recently started passenger service in the Chinese city of Yancheng. These are 36-metre-long, electrically driven buses with four vehicle modules and three joints, which - controlled purely by software - can transport up to 320 passengers on a virtually calculated tram track. The steer-by-wire system is completely electromechanical, complies with the ISO 26262-ASIL D standard and was developed by the Nabtesco group of companies - a pioneering achievement, as comparable systems have not been available on the market to date.
Concentrated mechatronic competence
For the realisation of the electromechanical steering system, Nabtesco, cycloidal transmission specialist and automation expert, and adcos, specialised development partner for software and hardware solutions in the field of mechatronic systems, have combined their competences and, within only seven months, put the first prototypes of the world's first steer-by-wire system for commercial vehicles on the test track or virtual test track. The innovative drive concept consists of a cycloidal transmission specially adapted to vehicle construction, a specially designed two-channel motor, a control unit and a sophisticated steering algorithm, and is precisely tailored for use in the high-voltage platforms of e-mobility. All safety-relevant elements are designed with redundancy. In total, each SRT has six interlinked steering drives mounted on the individual axles.
Cycloidal gearbox meets automotive
Cycloidal gearboxes are mainly known in robotics. But thanks to their high power density, reliability and robustness, the compact precision drives have long been at home in other high-tech applications as well and are conquering more and more new areas of application. They also have the decisive properties for use in automotive engineering. They are characterised by the highest precision, quality and economy, enable high torque performance in the smallest installation space and can be customised to individual requirements. In cycloidal gearboxes, power is transmitted via cam discs and rollers. This ensures high efficiency, enormous resistance to shock loads and minimal backlash over the entire service life.
Automation solutions for the mobility of tomorrow
From the robot into the vehicle: with the Chinese SRT project, Nabtesco once again underlines its innovative strength and technological leadership as an automation expert and system supplier. For the commercial vehicle industry, the innovative steering system from Nabtesco and adcos would open up completely new possibilities in the development of future-oriented transport concepts. This would then include doing without hydraulic systems and thus making buses and trucks more efficient, smarter, safer and more environmentally friendly. By the way: Other project partners include the two Swiss companies Balance Drive AG and Derap AG, which were responsible for project management.