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Technical Paper

FMVSS 126 Sine with Dwell ESC Regulation Test for Autonomous Vehicles

2019-04-02
2019-01-1011
Electronic stability control (ESC) has been an essential part of road vehicle safety for almost three decades. In April of 2007, the United States federal government issued a regulation to test the validity of ESC in development vehicles, and the regulation is called Federal Motor Vehicle Safety Standards (FMVSS) 126 in North America (NA), and an equivalent test in other countries outside of NA called ECE13-H (Economic Commission for Europe). While these standards have been used to certify ESC in development passenger cars for over a decade, this has not yet been scrutinized for the application of autonomous vehicles. Autonomous cars have sensors and control systems which can be used to improve ESC, where commercial standard vehicles do not.
Technical Paper

Study on a Method for Evaluating the Safety of the Braking Control Algorithm for Automated Driving System When Following

2019-04-02
2019-01-1015
The purpose of this study is to develop a method for evaluating the safety of the braking control algorithm for automated driving under mixed traffic flow of automated driving system and vehicles driven by drivers. We consider that the automated driving system should be controlled such that it blends in with mixed traffic. Therefore, in evaluating the safety of braking control for the automated driving system when following, the influence of the automated driving system on the driver of the following vehicle is an important evaluation index. First, we analyzed past traffic accidents in Japan to determine a suitable traffic environment for evaluating the safety of the braking control algorithm for the automated driving system when following. Second, the driver’s braking operations were measured using actual vehicles in this situation. We developed a method of generating sample algorithms of braking control based on the driver’s braking operations.
Technical Paper

Use of Machine Learning for Real-Time Non-Linear Model Predictive Engine Control

2019-04-02
2019-01-1289
Non-linear model predictive engine control (nMPC) systems have the ability to reduce calibration effort while improving transient engine response. The main drawback of nMPC for engine control is the computational power required to realize real-time operation. Most of this computational power is spent linearizing the non-linear plant model at each time step. Additionally, the effectiveness of the nMPC system relies heavily on the accuracy of the model(s) used to predict the future system behavior, which can be difficult to model physically. This paper introduces a hybrid modeling approach for internal combustion engines that combines physics-based and machine learning techniques to generate accurate models that can be linearized with low computational power. This approach preserves the generalization and robustness of physics-based models, while maintaining high accuracy of data-driven models. Advantages of applying the proposed model with nMPC are discussed.
Technical Paper

In-Gear Slip Control Strategy of Dry-Clutch Systems Using a Sliding Mode Control

2019-04-02
2019-01-1305
This paper proposes a clutch control strategy during in-gear driving situations for Dual Clutch Transmissions (DCTs). The clutch is intentionally controlled to make small amount of a slip to identify the torque transfer capacity. The control objective of this phase is to ensure the clutch slip fairly remaining the specified value. To achieve this, the micro-slip controller is designed based on sliding mode control theory. Experimental verifications performed on onboard control system of the DCT equipped vehicle demonstrate that the proposed controller good tracking performance of the desired slip speed.
Technical Paper

Full Battery Pack Modelling: An Electrical Sub-Model Using an EECM for HEV Applications

2019-04-02
2019-01-1203
With a transition towards electric vehicles for the transport sector, there will be greater reliance put upon battery packs; therefore, battery pack modelling becomes crucial during the design of the vehicle. Accurate battery pack modelling allows for: the simulation of the pack and vehicle, more informed decisions made during the design process, reduced testing costs, and implementation of superior control systems. To create the battery cell model using MATLAB/Simulink, an electrical equivalent circuit model was selected due to its balance between accuracy and complexity. The model can predict the state of charge and terminal voltage from a current input. A battery string model was then developed that considered the cell-to-cell variability due to manufacturing defects. Finally, a full battery pack model was created, capable of modelling the different currents that each string experiences due to the varied internal resistance.
Technical Paper

Control of the Effective Pressure in the Cylinder of a Spark-Ignition Engine by Electromagnetic Valve Actuator

2019-04-02
2019-01-1201
Internal combustion engines of vehicles which are equipped with classic drivetrains are mostly operating in variable load conditions. This fact especially refers to city driving, where the vehicle speeds are lower than in highway driving, but the accelerations are more frequent and intensive. The efficiency of the engine’s work is among others a load- and crankshaft rotation speed dependent parameter. Generally in low load conditions the efficiency of the engine is low, and in high load the efficiency is high. The authors conducted a series of road tests, searching for ranges of engine power most commonly used in urban traffic, adopting economical, dynamic and balanced driving strategies. In all strategies the passenger vehicle engine was most frequently operating in low power (and low efficiency) conditions. One of the ways to improve the efficiency of an IC engine is to raise its compression ratio (CR).
Technical Paper

Knock Thresholds and Stochastic Performance Predictions: An Experimental Validation Study

2019-04-02
2019-01-1168
Knock control systems are fundamentally stochastic, regulating some aspect of the distribution from which observed knock intensities are drawn. Typically a simple threshold is applied, and the controller regulates the resultant knock event rate. Recent work suggests that the choice of threshold can have a significant impact on closed loop performance, but to date such studies have been performed only in simulation. Rigorous assessment of closed loop performance is also a challenging topic in its own right because response trajectories depend on the random arrival of knock events. The results therefore vary from one experiment to the next, even under identical operating conditions. To address this issue, stochastic simulation methods have been developed which aim to predict the expected statistics of the closed loop response, but again these have not been validated experimentally.
Technical Paper

Extended Kalman Filter Based Road Friction Coefficient Estimation and Experimental Verification

2019-04-02
2019-01-0176
Accurate road friction coefficient is crucial for the proper functioning of active chassis control systems. However, road friction coefficient is difficult to be measured directly. Using the available onboard sensors, a model-based Extended Kalman filter (EKF) algorithm is proposed in this paper to estimate road friction coefficient. In the development of estimation algorithm, vehicle motion states such as sideslip angle, yaw rate and vehicle speed are first estimated. Then, road friction coefficient estimator is designed using nonlinear vehicle model together with the pre-estimated vehicle motion states. The proposed estimation algorithm is validated by both simulations and tests on a scaled model vehicle.
Technical Paper

Optimized Driving Cycle Oriented Control for a Highly Turbocharged Gas Engine

2019-04-02
2019-01-0193
The article is focused on a 1-D drive dynamic simulation of a highly turbocharged gas engine. A mono fuel CNG engine has been developed as a downsized replacement of the diesel engine for a medium size van. The basic engine parameters optimization is provided in a steady state operation and a control adjustment is applied to a dynamic vehicle model for a transient response improvement in highly dynamic operation modes of the WLTC (world light duty test cycle), selected for investigation. Vehicle simulation model with optimized control system is used for driving cycle fuel consumption and CO2 emissions predictions compared with the basic engine settings.
Technical Paper

Determining the Greenhouse Gas Emissions Benefit of an Adaptive Cruise Control System Using Real-World Driving Data

2019-04-02
2019-01-0310
Adaptive cruise control is an advanced vehicle technology that is unique in its ability to govern vehicle behavior for extended periods of distance and time. As opposed to standard cruise control, adaptive cruise control can remain active through moderate to heavy traffic congestion, and can more effectively reduce greenhouse gas emissions. Its ability to reduce greenhouse gas emissions is derived primarily from two physical phenomena: platooning and controlled acceleration. Platooning refers to reductions in aerodynamic drag resulting from opportunistic following distances from the vehicle ahead, and controlled acceleration refers to the ability of adaptive cruise control to accelerate the vehicle in an energy efficient manner. This research calculates the measured greenhouse gas emissions benefit of adaptive cruise control on a fleet of 51 vehicles over 62 days and 199,300 miles.
Technical Paper

Sensitivity Analysis and Control Methodology for Linear Engine Alternator

2019-04-02
2019-01-0230
Linear engine alternator (LEA) design optimization traditionally has been difficult because each independent variable alters the motion with respect to time, and therefore alters the engine and alternator response to other governing variables. An analogy is drawn to a conventional engine with a very light flywheel, where the rotational speed effectively is not constant. However, when springs are used in conjunction with an LEA, the motion becomes more consistent and more sinusoidal with increasing spring stiffness. This avoids some attractive features, such as variable compression ratio HCCI operation, but aids in reducing cycle-to-cycle variation for conventional combustion modes. To understand the cycle-to-cycle variations, we have developed a comprehensive model of an LEA with a 1kW target power in MATLAB®/Simulink, and an LEA corresponding to that model has been operated in the laboratory.
Technical Paper

A Fault Tolerant Time Interval Process for Functional Safety Development

2019-04-02
2019-01-0110
During development of complex automotive technologies, a significant engineering effort is often dedicated to ensuring the safe performance of these systems. An important aspect to consider when assessing the viability of different safety designs or strategies is the time period from the occurrence of a fault to the violation of a Safety Goal (SG). This time period is commonly referred to as the Fault Tolerant Time Interval (FTTI). In Automotive Safety, ISO 26262 [1] calls for the identification and appropriate partitioning of the FTTI, however very little guidance is provided on how to do this. This paper presents a process, covering the entire safety development lifecycle, for the identification of timing constraints and the development of associated requirements necessary to prevent Safety Goal violations.
Technical Paper

Research of Knocking Deterioration due to Accumulated Carbon Deposits on Piston Surfaces

2019-04-02
2019-01-1141
The quantity of heavy components in fuel is increasing as automotive fuels diversify, and engine oil formulations are becoming more complex. These trends result in the formation of larger amounts of carbon deposits as reaction byproducts during combustion, potentially worsening the susceptibility of the engine to knock [1]. The research described in this paper aimed to identify the mechanism that causes knocking to deteriorate due to carbon deposits in low to medium engine load ranges, which are mainly used when the vehicle drives off and accelerates. With this objective, the cylinder temperature and pressure with and without deposits were measured, and it was found that knocking deteriorates in a certain range of ignition timing.
Technical Paper

Intention Aware Motion Planning with Model Predictive Control in Highway Merge Scenario

2019-03-25
2019-01-1402
Human drivers navigate by continuously predicting the intent of road users and interacting with them. For safe autonomous driving, research about predicting future trajectory of vehicles and motion planning based on these predictions has drawn attention in recent years. Most of these studies, however, did not take into account driver’s intentions or any interdependence with other vehicles. In order to drive safely in real complex driving situations, it is essential to plan a path based on other driver’s intentions and simultaneously to estimate the intentions of other road user with different characteristics as human drivers do. We aim to tackle the above challenges on highway merge scenario where the intention of other road users should be understood. In this study, we propose an intention aware motion planning method using finite state machine and model predictive control without any vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) communications.
Standard

Safety Cable Kit Procurement Specification and Requirement for Use

2019-03-24
WIP
AS4536D

This procurement specification covers aerospace quality safety cable kits consisting of safety cables and ferrules made from the same corrosion and heat resistant steels and a nickel base alloy of the type identified under the Unified Numbering system as follows:

a. UNS S30400 - Corrosion resistant steel (AMS 5697)

b. UNS S32100 - Corrosion and heat resistant steel (AMS 5689)

c. UNS N06600 - Nickel base alloy (AMS 5687)

d. UNS N06625 - Nickel Alloy, Corrosion Resistant (AMS 5666)

The requirements for installation practices are also specified.

Technical Paper

Restricted Access ‘C’ Clamping Smart Drilling Unit

2019-03-19
2019-01-1334
One way assembly of aero structures has the potential to significantly reduce build times. One of the solutions, which goes towards achieving this philosophy, is the use of a ‘C’ clamping automated drilling system. The Manufacturing Technology Centre has developed and manufactured a ‘C’ clamping automated drilling unit to overcome many of the limitations of current designs, which prevent their use on a broader range of structures. The drilling unit addresses issues with access, size and weight restrictions as well as economic factors. This technical paper will present the outcomes from the design and manufacture of the drilling unit that is to be used within restricted access areas, as either a hand held device or as a robotic end effector free from any cables or hoses, allowing full and unhindered articulation of any robot motion. The device’s services: power, tool lubrication, swarf extraction and control systems have been designed to be embedded, rendering it a standalone unit.
Technical Paper

Collaboration in a Hybrid Team of Human and Robot for Improving Working Conditions in an Aircraft Riveting Process

2019-03-19
2019-01-1372
Aircraft production is facing various technical challenges, such as large product dimensions, complex joining processes, and organization of assembly tasks. Overcoming such challenges, as well as maintaining low tolerances and small batch sizes, is often difficult to achieve whilst retaining economic viability. ZeMA believes that a semi-automated approach is the most effective way to optimize aircraft section assembly. This can be achieved with a semi-automated riveting process for solid rivets, using Human-Robot-Collaboration in combination with an intuitive Human-Machine-Interaction operating concept. In the assembly of aircraft structures - in this scenario the aircraft aft section - the pressure bulk head is mounted to the section barrel. Two operators work collaboratively in uncomfortable, non-ergonomic positions, yet of course have to maintain exacting quality standards.
Technical Paper

A Predictive Reference Governor for Synchronous Generator Regulation with a Pulsed Constant Power Load

2019-03-19
2019-01-1379
In this paper, first an analytical model of a synchronous generator with a pulsed constant power load (CPL) is developed and numerically compared with a detailed simulation model. The analytical model is shown to possess good predictive abilities, thus enabling its use for control purposes. Second, the generator has a proportionalintegral (PI) control inner-loop, whose task is to regulate the generator’s output voltage to a desired reference. A novel outer-loop predictive reference governor (PRG) is designed and tested via simulation. The PRG uses the analytical model to predict the output behavior of the generator over a short time window, and continuously modifies the reference given to the inner-loop in order to maintain stringent steady-state requirements, in spite of demanding power requirements at the CPL. Simulation results illustrate the significant performance advantages of using the PRG versus using the inner-loop PI controller alone.
Journal Article

Development of a Learning Capability in Virtual Operator Models

2019-03-14
Abstract This research developed methods for a virtual operator model (VOM) to learn the optimal control inputs for operation of a virtual excavator. Virtual design, used to model, simulate, and test new features, has often been limited by the fidelity of the virtual model of human operators. Human operator learns, over time, the capability, limits, and control characteristics of new vehicles to develop the best strategy to maximize the efficiency of operation. However, VOMs are developed with fixed strategies and for specific vehicle models (VMs) and require time-consuming re-tuning of the VOM for each new vehicle design. Thus, there typically is no capability to optimize strategies, taking account of variation in vehicle capabilities and limitations. A VOM learning capability was developed to optimize control inputs for the swing-to-pile task of a trenching operation. Different control strategies consisted of varied combinations of speed control, position control, and coast.
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