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This technical paper reports the development of an automatic defect detector utilizing deep learning for “polished skins”. Materials with a “polished skin” are used in the fabrication of the external plates of commercial airplanes. The polished skin is obtained by polishing the surface of an aluminum clad material, and they are visually inspected, which places a significant burden on inspectors to find minute defects on relatively large pieces of material. Automated inspection of these skins is made more difficult because the material has a mirror finished surface. Defects are broadly classified into three categories: dents, bumps, and discolorations. Therefore, a defect detector must be able to detect these types of defects and measure the defects’ surface profile. This technical paper presents details related to the design and manufacture of an inexpensive automated defect detector that demonstrates a sufficiently high level of performance.

Machine learning is used for the research and development of ITS services and the rider assistance for on-road motorcycle racing. Meanwhile, rider assistance systems for off-road motorcycles have yet to be developed, partly due to the complexity of the measurement conditions, as described in the previous paper. This research aims to create a reliable AI which is capable of classifying typical jump behaviors in off-road riding by machine learning to create a rider assistance system for off-road motorcycles. Motorcycle manufacturers and certain research institutes use motion sensors to collect data, but the data is obtained from a limited number of vehicles and riders. The creation of a rider assistance system requires a large amount of validation data. Furthermore, it is desirable to achieve the target with data that can be measured in mass-produced vehicles, which will make it possible to collect data even from general users.

In this study, we efficiently predict the vibration response of a design shape at a low computational cost in the early development stage, select design proposals with good characteristics from many proposals devised by the designer at the early stage, and forward them to the next stage to achieve the front-loading of development while increasing product value. The application of participation factor (PF) focusing on the response at a specific part for vibration evaluation of a motorcycle frame is described. To reduce the motorcycle frame vibration, an eigenvalue analysis was performed, and appropriate design change proposals were efficiently selected using partial participation factor (PPF), an index showing the relevance of vibration of specific parts or positions. Using the PPF, we extracted which vibration modes considerably contribute to the vibration response of the part of interest.

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.

In this paper, it is also elucidated that the influence of the downstream injection, which caused different fuel behavior in contrast with upstream injection, on the THC after warm-up and at the maximum power, as well as its mechanism. The mechanism is clarified by use of the intake port visualization system. First, at each injection position, the effect of injection timing on THC emission after warm-up was evaluated. In the downstream injection, THC emission increases during the injection timing, in which the fuel spray directly flows in-cylinder during the intake process (hereinafter defined as the intake valve opening injection timing), and the amount of THC emission is reduced at the other injection timing (hereinafter defined as the intake valve closing injection timing). Based on the results of visualizing the intake port, injected fuel phase near the intake valve is spray in the downstream injection.

In port injection, it is difficult to control in-cylinder fuel supply of each cycle in a transient state as cold start (in this paper, cold start is defined as several cycles from cranking at low engine temperature). Hence, THC, which is one of regulated emission gases, is likely to increase at cold start. As one of THC emission reduction approaches at cold start, the optimization of fuel injection specifications (including injection position and spray diameter) is expected to reduce THC emission. Setting injection position as downstream position is expected to secure the in-cylinder fuel supply amount at cold start because of small fuel adhesion amount on an intake port wall and a short distance between the injection position and in-cylinder. The position injection contributes to reduction of THC emission due to elimination of misfire.

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.

This paper describes an engine mount system that achieves reduced vibration on an industrial type utility vehicle. First the vibration level and direction of the inline three cylinder engine installed in the vehicle was analyzed and based on these results a mount layout that leads to a reduced level of vibration felt by the passengers was developed. Next, this was applied on an actual vehicle and spring characteristics were designed for each mount. The actual spring constants were set such that when considering the engine to be a rigid body, the resonance frequency thereof occurs at an engine speed lower than idle and in addition were set to ensure component strength relative to driving forces and inertial forces that act while the utility vehicle is being driven. Lastly, achievement of significant vibration reduction was confirmed on an actual vehicle showing that this engine mount system is effective at reducing vibration.

As for automobile, the mass production period of Electric Vehicle(EV) has begun by the rapid progress of the battery performance. But for EV-Motorcycle(MC), it is limited for the venture companies' releases. The design and evaluation methodologies are not yet established or standardized so far. This paper provides the practical and the experimental examples. To study the feasibility of EV-MC, we developed the prototypes in the present technical and suppliers' parts environments, and evaluated them by the practical view of the MC usage. The developed EV-MC has the equivalent driving performance of the 250cc internal combustion engine(ICE)-MC and a cruising range of 100km in normal use.

As for automobile, the mass production period of Electric Vehicle(EV) has begun by the rapid progress of the battery performance. But for EV- Motorcycle(MC), it is limited for the venture companies' releases. The design and evaluation methodologies are not yet established or standardized so far. This paper provides the practical and the experimental examples. To study the feasibility of EV-MC, we developed the prototypes in the present technical and suppliers' parts environments, and evaluated them by the practical view of the MC usage. The developed EV-MC has the equivalent driving performance of the 250cc internal combustion engine(ICE)-MC and a cruising range of 100km in normal use. In the prototype development, the reliability and the ability of protection design of the battery in the whole vehicle against the environmental loads are mainly studied, especially, heat and cold, water, shock, and the accident impact.

We developed active control more suitable for sports riding than the previous electronic stability control system for enjoying sports riding by many users. One of them, the traction control system S-KTRC (Sports Kawasaki TRaction Control) uses the sensor output like not only the slippage calculated from the front and rear wheel speed but also engine speed, throttle position, and gear position etc. As the result, conditions of the motorcycle and rider's intention are calculated by ‘Motorcycle model’ in the ECU continuously. By this ‘Motorcycle model’, S-KTRC confirms the real time conditions and predicts the succeeded condition, every 5milliseconds to decide to govern torque. The ABS system KIBS (Kawasaki Intelligent anti-lock Brake System), it is possible to control the rear wheel's lift by using the pressure data of the front brake at the sudden braking operation.

In this study, the technology that can predict fatigue life for motorcycle exhaust systems is developed. To predict the fatigue life, analyzing the engine vibration, modeling the vibration characteristics of exhaust systems and evaluating the fatigue damage of welded joints are considered essential. This paper shows an integrated numerical simulation and evaluation method. Furthermore, it is also shown with the result of a component vibration test of the muffler assembly to validate the technology. The results indicate a good correlation between the numerical simulation and the test.

At the upstream part of the Three-Way Catalyst (TWC) an O₂ sensor (UpO₂S) is used for O₂ Feedback Control (O₂F/B) that controls the air-fuel ratio (A/F) close to the stoichiometric level. O₂ sensor has a bit of individual characteristic difference as for the switching the excess air ratios of output (λ shift). This phenomenon becomes remarkable according to the effects of unburnt elements in exhaust gas. Despite the O₂F/B implementation, A/F isn't controlled to the stoichiometric level and the conversion efficiency of the TWC could be lower. Maintaining a higher level of TWC conversion efficiency requires more accurate A/F control and corrections of the UpO₂S λ shift issue. Therefore, using an O₂ sensor at the downstream part of the TWC (DownO₂S)~where the effects of unburnt elements in exhaust gas are smaller~can be an effective way to restore these challenges.

In recent years, even motorcycles impose demands for engine power controls that are more flexible and precise. The Electronic Throttle Control (ETC) system is one of the methods that addresses this need. However, the most important issue facing the installation of the ETC system on the motorcycle is handling failures. To avoid this problem, we developed an ETC system for motorcycles that can properly effect engine power control in case of a failure. This ETC system contains in duplicate the major components to detect failures and switch to a failure mode properly. To effect control that is optimally suited to the type of failure, this system switches between three types of failure modes. These failure modes are designed to minimize risks in case of a failure and maximize the operational capability while the rider is on the way to have the motorcycle repaired.

The Advanced ECS is under development for the purpose of saving fuel, improving safety, and cabin comfort. In FY2006 study, basic components (i.e. MDC, OBNOGS, desiccant units, and CO2 removers) have been improved and their performances evaluated including resistance to environmental condition (i.e. vibration). In addition, the suitable system configuration for a 90-seats aircraft has been considered to evaluate the feasibility of the system. In this paper, we show the results of the evaluated performances based on prototype components, and the analytical study of a revised system configuration.

This paper describes a numerical analysis method for predicting the brake squeal using the Substructure Synthesis Method. This method is more accurate than the classical method based on the mass-spring system, and simpler than the analysis of all the brake system by FEM. The squeal studied here is focused the one occurring in the low frequency range and its mechanism is due the structural instability of the brake assembly. First, some experiments were carried out in order to grasp the brake squeal phenomenon. These experiments made clear the following items. (1) The low frequency brake squeal occurred at 850Hz. (2) The vibration mode shape had 5 nodes fixed in a space. (3) The brake squeal became maximum at 0.3 - 0.5 (MPa) liquid pressure under the constant temperature condition. (4) The higher the temperature of the pad was, the stronger the brake squeal was under the constant liquid pressure condition.

Motorcycle engines are operated at an extremely broad range of revolutions, from 1000 min-1 to 10000 min-1 or more. Ideally, the natural frequency of each part should never match the engine excitation frequency at any point over that entire range of revolution speeds, but practically, there are times when resonance cannot be avoided because the range is so broad, and therefore the vibration amplitude at resonance must be kept low. For this reason, it is important to grasp not only the resonance frequency but also the vibration amplitude at that point. This may be achieved by two methods, measurement and analysis. The direct measurement of vibration is generally difficult because the motorcycle muffler system has a complex shape and in addition it gets very high temperature when the engine is operating. For this reason, with the aim of being able to predict muffler vibration at the design stage, we carried out a vibration test and FEM (finite element method) analysis.

The authors developed an air-to-air surveillance system that acquires mutual position and informs the position to the pilot. This system transmits position information obtained by GPS via TDMA (Time Division Multiple Access) datalink. Position information received from other aircraft is shown on a display. If proximity condition exists, voice alert is activated. This system can be used as an support system for collision avoidance. This paper describes the outline of the system and flight test result. Two prototype systems were installed on two helicopters. The third system was installed on a ground vehicle. Flight tests were performed using these three systems.

This paper describes the predicted results of acoustic transmission loss (T.L.) for a motorcycle muffler. First, the T.L. of a prototype muffler with one expansion chamber was obtained by measuring sound levels at the inlet and outlet ports of the muffler by speaker test. T.L. was then calculated by using a three-dimensional Finite-Element Method (FEM) for acoustic fields in the muffler. There was good coincidence between the calculated T.L. and experimentally observed data. Second, T.L. of the prototype muffler while attached to a motorcycle engine was measured. On this step, however, a similarly calculated T.L. using FEM to consider the effect of exhaust gas temperature in the muffler showed differences from the measured one. It was estimated that muffler body vibration sounds may affect the result. A dynamic analysis of the structure was carried out using FEM to obtain the eigen modes of the muffler body.