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This paper presents a method of trailer yaw stabilization for a tractor-trailer by automatic differential braking of trailer rear wheels. It is implemented as part of an ABS based upon a sliding mode observer (SMO). The trailer rear wheel brakes are alternately applied according to a control law derived from measurements of trailer yaw (relative to the tractor axis). The SMO provides an additional control function that prevents wheel lock. Brakes are applied in response to a control signal that is generated from measurements of trailer yaw. The SMO-based ABS regulates braking to prevent wheel lock and to simultaneously optimize yaw control.

A method is presented here that detects aircraft tail surface icing that might normally be unobserved by the flight crew. Such icing can be detected through the action of highly computationally efficient signal processing of existing sensor signals using a so-called failure detection filter (FDF). The FDF creates a unique output signature permitting relatively early detection of tail surface icing. The FDF incorporates a stable state estimator from which the icing signature is created. This estimator is robust to analytical modeling errors or uncertainties, and to process noise (e.g. turbulence). Excellent performance of the method is demonstrated via simulation.

Control of an antilock brake system for aircraft and land vehicles is based upon estimates of the torque applied to braking wheels by means of a sliding mode observer. The observer yields a highly accurate estimate of torque that is robust for the entire operating range of the brakes, and provides an input to a relatively simple control system that regulates applied torque from either an electro-hydraulic or electromechanical actuator. Excellent braking performance for a regional jet transport is demonstrated in this paper via hardware-in-the-loop simulation. A simple scheme for suppressing gear walk (aircraft application) is presented.

This paper presents the theory and experimental performance of a system for detecting engine misfires in automobiles. The method is potentially suitable for meeting the California Air Resources Board (CARB) requirements under On Board Diagnostics II (OBDII) rules. The instrumentation for the present method measures (noncontacting) crankshaft instantaneous angular speed. Highly efficient signal processing algorithms permit detection of each individual misfire. The performance of the present method is expressed in terms of error rates made in detecting individual misfires. Normal operating conditions yield error rates under 10-4. Under worst case conditions consisting of light load, high RPM and rough roads with the torque converter in lockup are under 10-3.

The integrity of the exhaust emission system in a passenger vehicle can best be maintained by monitoring its performance continuously on board the vehicle. It is with the intent of monitoring emission system performance that the California Air Resources Board has proposed regulations which will require vehicles to be equipped with on-board monitoring systems. These proposed regulations are known as OBDII and will probably be followed by similar Federal EPA regulations.This paper discusses a method of monitoring engine misfire as part of the OBDII requirements for passenger vehicle on-board diagnostics. The method is relatively inexpensive in that it uses an existing sensor for measuring instantaneous crankshaft angular position, and utilizes electronic signal processing which can be implemented in relatively inexpensive custom integrated circuits.

This paper introduces a high accuracy method of measuring crankshaft angular position of an I-C engine. The method uses a sensor which couples magnetically to the starter ring gear. There are many automotive applications of this measurement of crankshaft angular position including ignition timing reference, engine performance measurement and certain diagnostic functions. The present paper disusses only the ignition timing application. Engine performance measurements are reported in refs. (1,2,3). The diagnostic application is discussed in refs. (4-5). The passage of a starter ring gear tooth past the sensor axis causes a pulse to be generated in the sensor output. The waveform of this sensor voltage is independent of engine angular speed (including zero speed). However, this waveform is a function of gear tooth profile and is consequently influenced by gear wear. The present method uses a finite state machine to process the sensor output signal.

This paper presents the experimental results of measurement of the nonuniformity in diesel engine torque. Measurements were made for an engine driving a water brake dynamometer as well as for a diesel engine (with a manual transmission) in an actual vehicle on roads of varying surface quality. These nonuniformity measurements are a measure of engine performance and have potential application in electronic engine control, maintenance/diagnostic functions and can serve as an indicator of incipient failure of the engine or of certain components. The instrumentation includes a noncontacting (magnetic field system) sensor which can be mounted on the engine with minimal modification. The computation of the nonuniformity index can be implemented with an 8-bit or 1-6-bit microcomputer This paper presents the theory of the method, explains the necessary instrumentation, and gives results of the experimental study.

This paper presents a new metric for the nonuniformity of the torque random process of a reciprocating internal combustion engine. The proposed metric is derived from the torque 2N extrema which occur within each engine cycle for an N-cylinder engine. A 2N-dimensional vector is obtained for each cycle, which represents torque nonuniformity. The proposed metric is either the 11 or 12, norm for this vector. It is shown in this paper that this metric satisfies several properties which are desirable for quantitatively representing torque nonuniformity. Moreover, this metric is computed once each engine cycle and is, therefore, a quasi-real time measure of torque nonuniformity. This metric has several potential applications in electronic engine control systems.