Title

The History of Two-wheeled Vehicle Dynamics in Japan and Subsequent Trends

Abstract

Japan had been closed off from the rest of the world for about 220 years until 170 years ago, and as a result, a variety of academic disciplines were developed independently. For example, in the field of mathematics, using "Wa-san (Way of Japanese Mathematics)", Kowa Seki derived a method for finding solutions to simultaneous equations by the method of elimination 70 years before Europe. In addition, calculation of π was presented in the 1600s, showing up to 26 digits by him. Furthermore, there are references to the use of derivatives in analysis, although the method of expression is different. Thus, a unique academic culture developed in Japan. However, while it has attracted attention in Japan as historical research material, its achievements have not received much attention, and the academic systems established in the western countries have been emphasized. One of the characteristics of the Japanese academic system is that many academic discussions, including those in the engineering field, have been conducted in Japanese due to the environment in which students can study in Japanese, including reference materials in the latest academic fields. Therefore, while it has been easy to develop academic studies in Japan, the language barrier, such as English, has been a major bottleneck to exchange with foreign countries.

Turning to the motorcycles, the industry expanded rapidly after World War II, as many companies entered the motorcycle manufacturing business. In response to this trend, Masaichi Kondo, an aeronautics scholar, conducted vigorous research activities focusing on the stability and handling of motorcycles and four-wheeled vehicles. In 1948, the basic equations of motion and steady state turning characteristics of motorcycles were presented. Later, in 1955, these were compiled, and the study of motorcycle dynamics was published. From the mid-1950s to the early 1960s, many experimental and theoretical studies related to motorcycles were conducted in Japan. As research worthy of attention at the time, studies on modeling and stabilization of riders operating motorcycles were already conducted in 1962, using feedback control theory. Later, in the mid-1960s, more attention was paid to tire characteristics from a dynamics point of view, and the results of these measurements were also published. However, most of the research on motorcycles in Japan is difficult to obtain due to the fact that almost of these were handwritten lecture manuscripts, and has not received much attention worldwide. For this reason, many researchers consider the motorcycle dynamics published by Sharp in 1971 as the starting point for full-scale research on motorcycle dynamics, and in recent years, even in Japan, many researchers in this field have discussed on the basis of the equations of motion by Sharp.

Having had the opportunity to give a keynote lecture on motorcycle dynamics at BMD, I have decided to summarize how research on motorcycle dynamics and kinematics have developed in Japan and how it has evolved since then, focusing particularly on research conducted in Japan. In my presentation, I would like to divide the dynamics of motorcycle kinematics into several areas and show what research has been done in each of these individual areas.

Biography

Academic Activities:

• 1977-2020 Nihon University College of Industrial Technology (From 1994- 2020 Professor in Nihon University)
• 1989-1990 Guest researcher at Technical University of Delft (The Netherlands)
• 2024 Guest researcher at Swedish National Road and Transport Research Institute (VTI) (Sweden)
• 2010-2017 Director of Center for Automotive Research (NU-CAR)
• 2014-2020 Visiting Professor at Nagoya University
• 2020- Professor Emeritus of Nihon University
• 2020- Representative Director of Consortium on Advanced Road-Friction Database
• JSAE Fellow, JSME Fellow
• General Chairman of AVEC’02
• General Chairman of BMD’13

During this period, his research interests included vehicle dynamics (Articulated vehicle dynamics, passenger car dynamics, motorcycle dynamics, tire characteristics and modeling), vehicle motion control (driver models, rider models, autopilot vehicle, construction of rider robot), and human-machine systems (human interface, human vibration characteristics), and so on.