Shigeru Oho

CPU Model-Based Hardware/Software Co-design, Co-simulation and Analysis Technology for Real-Time Embedded Control Systems

This paper proposes a new development method for highly reliable real-time embedded control systems using a CPU model-based hardware/software co-simulation. We take an approach that allows the full simulation of the virtual mechanical control system including the mechatronics plant, microcontroller hardware and object code level software. This full virtual system simulation reveals the control system behavior, especially in microcontroller hardware and software. It enables microarchitecture design space exploration, control design validation, robustness evaluation of the system, software optimization before components design, and prevents potential problems. A novel aspect of this work is that the proposed virtual control system comprises all the components in a typical control system, therefore it enables the analysis of the effects from the different domains, for example the mechanical analysis of behavior due to a control software bug. To help the design, evaluation and analysis, we developed an integrated behavior analyzer into the development environment. This can display the processor behavior graphically during the simulation without affecting the simulation results, such as task level CPU load, interrupt statistics and software variable transition chart. This analyzer provides useful information on the behavior. No software modification is necessary for this virtual system analysis, and this analysis does not change the control timing and does not require any processing power on the target microcontroller. Therefore this method is suitable for real-time embedded control system design, in particular automotive control system design which requires high level reliability, robustness, quality and safety. In this paper, a Renesas SH-2A microcontroller model was developed on a CoMETtrade platform from VaST Systems Technology. An ETC (electronic throttle control) system is chosen as the plant to prove this concept. The ETB (electronic throttle body) model on Saberreg simulator from Synopsysreg was co-simulated with the SH-2A model. The SH-2A chip was under development during this project, nevertheless we could complete the OSEK OS development, control software design and verification using the virtual system. We confirmed that such software could run on an actual ETC hardware system without modification after a working sample chip was released at a later stage in the course of this work. This demonstrates that our models and simulation environment are sufficiently credible and trustful

A Kalman filter to estimate direction for automotive navigation

A Kalman filter algorithm to estimate direction for automotive navigation is reported. An extended Kalman filter is used to combine a magnetic compass and a rate gyroscope and to compensate for the sensor errors; the result is an optimal estimate for heading direction. A mathematical model for magnetic compass errors caused by body magnetization and the body effect of magnetic material is proposed. An error model of the rate gyroscope is also established. Errors of both sensors are calibrated through a computer simulation. Finally, experimental navigation results are demonstrated.

Optical fiber gyroscope for automotive navigation

The use of an optical fiber gyroscope in automotive navigation is reported. The performance requirements for a navigational gyroscope are discussed in terms of the input range, resolution, and bias and scale errors. The OFG-3, an automotive optical fiber gyroscope prototype, is introduced, and its error sources are related to the gyroscope designs. The gyroscope is made of polarization maintaining fibers and incorporates optical phase modulation and synchronous demodulation techniques. The gyroscope electronics restrict the resolution and the bias error, while the optics dominate the scale error. The microcomputer in the electronics compensate for the scale error, and the OFG-3 meets navigational requirements. Automotive navigation has been demonstrated using the gyroscope in combination with a map-matching algorithm. >

Wavelet-based knock detection with fuzzy logic

This paper presents a novel approach to the determination of the knocking condition of a spark-ignition engine using the discrete wavelet transform as a means of analyzing the engine-block vibration signal and a fuzzy inference scheme to generate an estimate of the knock intensity. The block vibration sensor responds to knock-induced pressure waves generated when a portion of the air-fuel mixture in the cylinder combusts spontaneously. However, the block vibration signal is masked by other excitation signals, which render the deter- mination of the knocking condition of the combustion a difficult task. The wavelet transform lends itself very useful to the time-frequency analysis of the vibration signal. Various characteristic features can be determined from the wavelet decomposition of the signal. These are in turn fused together to generate an estimate of the knocking in- tensity using fuzzy logic. The proposed scheme was developed and tested using engine combustion data processed off-line. Off-line data was also used to optimize the parameters of the fuzzy scheme. The sys- tem was subsequently implemented on the real-time engine controller for on-line testing.

Recent developments of optical fiber sensors for automotive use

Abstract Optical fiber sensing technologies are expected to apply for many future electronic control systems in automobiles, because of their inherent outstanding features, such as high noise immunity, high heat resistance, and flexible light propagation paths which can be applied to measure the movements and directions of the mobiles. In this paper, two typical applications of fiber sensing technologies in automobiles are described in detail. The combustion flame detector is one of the typical applications of a fiber spectroscopic technology which utilizes the feature of high noise and heat resistibility and remote sensibility. Measurement of engine combustion conditions, such as the detonation, the combustion initiation, and the air-fuel ratio, have been demonstrated in an experimental fiber sensing method. Fiber interferometers, such as a fiber gyroscope, have great possibilities in future mobile applications because they are applicable to many kinds of measurements for movements and physical variables...

Recent Developments Of Optical Fiber Sensors For Automotive Use

Optical fiber sensing technologies are expected to apply for many future electronic control systems in automobiles, because of their original outstanding features, such as high noise immunity, high heat resistance, and flexible light propagation paths which can be applicable to measure the movements and directions of the mobiles. In this paper, two typical applications of fiber sensing technologies in automobiles have been described in detail. The combustion flame detector is one of the typical applications of a fiber spectroscopic technology which utilizes the feature of high noise and heat resistibility and remote sensibility. Measurements of engine combustion conditions, such as the detonation, the combustion initiation, and the air-fuel ratio, have been demonstrated in an experimental fiber sensing method. Fiber interferometers, such as a fiber gyroscope, have a lot of possibilities in future mobile applications because they are expandable to many kinds of measurements for movements and physical variables. An optical fiber gyroscope utilizing the single polarized optical fiber and optical devices has been developed. Quite an accurate measurement of vehicle position was displayed on a prototype navigation system which installed the fiber gyroscope as a rotational speed sensor.

Contactless liquid-level measurement through opaque container using millimeter-wave sensor

A novel contactless method for measuring liquid level through an opaque container is proposed. A millimeter-wave Doppler sensor is used to “see” through a target container and measure the liquid level on the basis of the absorption of millimeter waves in liquid. One of the challenges is to achieve accurate liquid-level measurement (within sub-millimeter error) despite the inherently large beam-spread angle of the millimeter wave due to diffraction. A piezoelectric vibrator enables accurate measurement by reflecting a limited portion of the spread beam and modulating it to distinguish it from the other portion of the beam. The feasibility of the proposed method for clearly detecting an air-liquid interface concealed in an opaque container was confirmed experimentally. Nonlinearity error of the measured liquid level was within ±0.5 mm, which is the first demonstration of accurate liquid-level measurement using a millimeter-wave sensor.

Multiplex in-cylinder pressure measurement utilizing an optical fiber with specific refractive-index composition

An approach to multiplex in-cylinder pressure measurement that utilizes a single-mode optical fiber with specific refractive-index composition has been proposed. The sensing fiber has been designed to show a certain amount of optical power loss with a small change in the fiber-local-bend radius. Along with pressure-transferring diaphragms the sensing fiber was embedded into the head gasket of a four-cylinder gasoline engine. The internal-pressure change in each combustion chamber was detected on the basis of bending power loss in the fiber. Combustion pressure peaks for each cylinder were clearly observed.

Fiber optic gyroscopes for vehicle navigation systems

Fiber optic gyroscopes (FOGs) have been developed for vehicle navigation systems and are used in Toyota Motor Corporation models Mark II, Chaser and Cresta in Japan. Use of FOGs in these systems requires high reliability under a wide range of conditions, especially in a temperature range between -40 and 85 degree(s)C. In addition, a high cost-performance ratio is needed. We have developed optical and electrical systems that are inexpensive and can perform well. They are ready to be mass-produced. FOGs have already been installed in luxury automobiles, and will soon be included in more basic vehicles. We have developed more inexpensive FOGs for this purpose.

Development of open-loop fiber optic gyroscopes for industrial and consumer use

Fiber optic gyroscopes (FOGs) are developed for industrial and consumer applications. The bias error, which is determined by electrical circuits rather than the optical system, varies between 0.01 and 36 deg/hr depending on the construction of the electrical system. The scale factor error at each input rate is less than 0.5% in the temperature range of -30 to 85 degree(s)C. These FOGs are compact, highly reliable, and need only a +12 V D.C. power source. They are ready for mass production.