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Electronically controlled suspensions are expected to improve driving performance as the damping characteristics of the suspension can be adjusted in real time to respond to road conditions. This paper reports the results of testing the suspension control logic for improving ride quality, especially when driving on rough roads, using an internally developed riding simulator. The skyhook theory is widely known as a control logic for reducing vibration when driving a four-wheeled vehicle on a rough road, which we utilized in our riding simulator to examine the vibration reduction effects when applying control logic for motorcycle suspensions. The test results show that the skyhook theory can be applied in motorcycles. However, sensors for suspension systems that can be installed in mass-produced motorcycles are severely limited in terms of cost and space.

We developed the motorcycles based on RIDEOLOGY (Ride + Ideology) concept. In the past, the “Ride” was studied by a sensory evaluation with actual driving. However, the recent progress in numerical analysis, there have been developed driving simulators. It allows more quantitative measurement in a sensory evaluation. Therefore, we also developed a riding simulator specialized for motorcycles. In order to develop such riding simulator, there are some technical challenges for motorcycles. First, we need to reproduce roll motion height of motorcycles. Compared to four-wheeled vehicles, motorcycles have a higher center of rotation. Second, we need to reproduce vehicle motion control by rider’s changing body position. A rider controls vehicle’s lean by shifting his center of gravity. Therefore, it is necessary to construct a measurement system of rider’s body position. Third, we need to improve senses of speed and reality.

Owing to the recent developments in sensors with reduced size and weight, it is now possible to install sensors on a body of a motorcycle to monitor its behavior during running. The analysis of maneuverability and stability has been performed based on the data resulted from measurements by these sensors. The tire forces and moments is an important measurement item in maneuverability and stability studies. However, the tire forces and moments is difficult to measure directly, therefore, it is a common practice to measure the force and the moment acting on the center of the wheel. The measuring device is called a wheel forces and moments sensor, and it is widely used for cars. The development of a wheel forces and moments sensor for motorcycles has difficulty particular to motorcycles. First, motorcycles run with their bodies largely banked, which restricts positioning the sensors.

In motorcycles, the size and output performance of the engine itself has a major effect on the maneuverability of the motorcycle. In particular for cases where a high output engine is mounted on a lightweight frame, these effects are even more of a concern. In the case of developing a racing motorcycle with a high power engine, the behavior of the motorcycle differs depending on the output range used and there are a lot of cases where changes to the basic dimensions of the motorcycle as well as the main components are required. Here, there are a lot of cases where the rider and drive-able courses are limited to compatibility with distinct specifications and when considering use as a general mass production motorcycle by riders with varying levels of skills and in various environments, it difficult to determine how to provide support.

High performance motorcycles require dynamic performance that encompasses superior handling, wherein the wheels are one of the key components that determine the dynamic performance of the motorcycle. In this paper, we will clarify the dynamic parameters for the wheels that have an impact on the handling while also constructing a design technique in which numerical shape optimization is applied.

In this study, a technology for measuring dynamic deformation of motorcycle bodies in running is developed. The deformation has significant association with the maneuverability and stability of motorcycles. The developed system by combining the numerical simulation and the measurement of strains enable application of the measurement of dynamic deformation of motorcycles. This paper reports technical details of the system and measurement results of dynamic deformation of motorcycle bodies.