Study on the potential application of electronic wedge brake for vehicle brake system

This paper presents a study of the potential application of an electronic wedge brake for vehicle brake system using human-in-the-loop simulation. Simulation was made in MATLAB Simulink software which interfaces an imaginary vehicle with a real time input from a human, such as throttle and brake input. The imaginary vehicle model that is used is a vehicle dynamic model that has been validated experimentally using an instrumented experimental vehicle. A validated electronic wedge brake actuator model was then used as the brake actuator model where a suitable control strategy, namely proportional-integral-derivative and proportional-integral controllers, was utilised as the force and gapping control respectively. To verify the effectiveness of the proposed actuator in a vehicle, the simulation results are compared with the results of human-in-the-loop simulation of a vehicle using a conventional hydraulic brake and the response of the experimental vehicle using the same dynamic test, namely the sudden braking test. The simulation results show that the proposed simulation method and actuator with appropriate controller strategy have similar behaviour to a hydraulic brake in terms of its capability to produce the desired braking force to reduce the speed and halt the vehicle. The outcomes from this study can be considered in design optimisation and implementation in a real vehicle

Experimental verification of understeer compensation by four wheel braking

This study is designed to validate a new approach to understeer mitigation chassis control, based on a particlemotion reference: parabolic path reference (PPR). Considering the scenario of excess entry speed into a curve,related to run-off-road crashes, the aim is that automatic braking minimizes lateral deviation from the target pathby using an optimal combination of deceleration, cornering forces and yaw moments. Previous simulationstudies showed that four-wheel braking can achieve this much better than a conventional form of yaw momentcontrol (DYC). The aim of this work is to verify this on a test track with an experimental vehicle, and to compareperformance with DYC and an uncontrolled vehicle. Experiments were performed with a front-wheel-drivepassenger vehicle equipped with an additional four identical brake callipers controlled via an electro-hydraulicbrake (EHB) system, enabling individual brake control. Minimizing the maximum deviation from the intendedcurve radius is the control objective. Feedback to the controller consists of the available steering wheel angle,wheel speeds, yaw rate and lateral acceleration sensors in the vehicle. Additional to these variables, also thevehicle position was logged using a GPS system. It was found that PPR is superior to DYC in reducing themaximum deviation from the intended path, confirming the trends previously found in simulations. Furthermore,the PPR concept is found to be inherently more stable than DYC since more brake force is applied to the outerwheels than the inner wheels throughout the manoeuvre. The experiments involve a first implementation of aPPR control which is not a fully closed-loop control intervention and tuned to a step steer (transition fromstraight to fixed-radius curve. This is the first study to explicitly and systematically evaluate this new approachto understeer mitigation. The approach is fundamentally different from common DYC and suggests the potentialfor a new generation of controllers based on trajectory control via chassis actuators

Electric-drive vehicle emulation using advanced test bench

Vehicle electrification is considered to be the most promising approach toward addressing the concerns on climate change, sustainability, and rapid depletion of fossil fuel resources. As a result electric-drive vehicle (EDV) technology is becoming the subject of many research studies, from academia and research laboratories to automotive industries and their suppliers. However, a crucial step toward the success of EDV implementation is developing test platforms that closely emulate the behavior of these vehicles. In this dissertation, a new approach for emulating an EDV system on a motor/dynamometer test bench is investigated. Two different methods of emulation are discussed which are based on predefined drive cycle and unpredictable driving behavior. MATLAB/Simulink is used to model the test bench and simulations are carried out for each case. Experimental test bench results are also presented to validate hardware-in-the-loop (HIL) real-time performance for each method. Furthermore, to provide a more realistic approach towards EDV emulation a braking system suitable for motor/dynamometer architecture is proposed. The proposed brake controller represents a very close model of an actual EDV braking system and takes into account both regenerative and friction braking limitations. Finally, the challenges and restrictions of using a full scale test bench are outlined. To overcome these limitations, the development of an educational small scale hybrid electric vehicle (HEV) learning module is discussed which provides an ideal test platform to simulate and study both electric and HEV powertrains --Abstract, page iv

Analysis of air flow and heat dissipation from a high performance passenger car front brake rotor

The increasing demand from the consumer for higher levels of refinement from their passenger vehicles has put considerable pressure on the automotive industry to produce ever quieter cars. In order to prevent the occurrence of many forms of brake noise, especially judder and drone, excessive heating of the brake disc must be avoided, whilst minimising temperature variations across the rotor. In order for this to be achieved the brake rotor must be designed such that it ensures sufficient uniform heat dissipation and thermal capacity. In high demand braking applications vented discs consisting of two rubbing surfaces separated by straight radial vanes are normally employed as they utilise a greater surface area to dissipate heat. Within this paper the convective heat dissipation from a high performance passenger car front brake disc has been investigated using computational fluid dynamics (CFD). The results obtained have been validated by those obtained in preliminary vehicle testing at Millbrook test facility. The computational model shows adequate correlation to the test results; overpredicting the average heat transfer coefficient by 18%. The CFD analysis enabled a detailed insight into the air flow and heat transfer distributions, that was not possible during the vehicle test regim

Autonomous Driving Platform Performance Analysis

Through data analysis of various plots and figures it will be possible to determine the best control parameters to get the best performance out of the autonomous driving platform. This data, presented in this thesis, will show quantitatively what the best control strategies are through comparison of different versions of the platform

GPS-guided mobile robot platform featuring modular design elements for agricultural applications : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Engineering in Mechatronics at Massey University Turitea Campus, Palmerston North, New Zealand

The agricultural industry has not seen significant innovation in development of low-cost automated farming solutions, with current systems costing several thousands of dollars to implement. Currently these automated solutions are primarily implemented around crop planting and harvesting, and the large implementation cost of these systems makes them unfeasible for small-scale operations. Within many agricultural industries, workers expend a considerable amount of time undertaking simple tasks that are labour intensive. Many of these tasks could instead be completed using a self-driving robotic platform outfitted with the appropriate devices required for the tasks. This thesis covers the research work aiming to produce a solution that could turn an existing farming vehicle into a multipurpose low-cost agricultural platform, to act as the platform for an autonomous vehicle capable of performing pre-programmed tasks within an agricultural environment. A quad bike was selected as the vehicle platform for this research in which the control modules would control the speed and direction of this farm bike. Four modules were developed to control the vehicle components that would normally be operated by a human operator. These modules are comprised of mechanical actuators coupled with a microcontroller control system and includes some specific designs to maintain the user's ability to manually control the pre-existing systems. A gear-changing module controls the vehicles manual gearbox, providing a method to detect and control the vehicles current gear. A speed control module was developed to control the vehicles throttle and braking system and detects the vehicles speed. A steering module controls the vehicles steering system, allowing for accurate control of the vehicles direction. Finally, a vehicle controller module provides a central command interface that ties the previous three modules together and controls the vehicles electrical components and engine. Development of a low-cost differential GPS (DGPS) system was also undertaken to reduce the implementation cost of the system. Due to inconclusive results in relation to the positional accuracy of this system is was decided that a standard GPS system would be used for the vehicle prototype with further development on the DGPS system would be undertaken in future development of the research. The successful development of a farm automated vehicle platform was achieved through this research. With further improvement on software, intelligent control and the development of a low-cost differential global positioning satellite (GPS) system, a fully autonomous farm platform that can be outfitted with different tools or devices for the required farm tasks is feasible and practical

An investigation into hybrid power trains for vehicles with regenerative braking

Imperial Users onl

Automated Transit Networks (ATN): A Review of the State of the Industry and Prospects for the Future, MTI Report 12-31

The concept of Automated Transit Networks (ATN) - in which fully automated vehicles on exclusive, grade-separated guideways provide on-demand, primarily non-stop, origin-to-destination service over an area network – has been around since the 1950s. However, only a few systems are in current operation around the world. ATN does not appear “on the radar” of urban planners, transit professionals, or policy makers when it comes to designing solutions for current transit problems in urban areas. This study explains ATN technology, setting it in the larger context of Automated Guideway Transit (AGT); looks at the current status of ATN suppliers, the status of the ATN industry, and the prospects of a U.S.-based ATN industry; summarizes and organizes proceedings from the seven Podcar City conferences that have been held since 2006; documents the U.S./Sweden Memorandum of Understanding on Sustainable Transport; discusses how ATN could expand the coverage of existing transit systems; explains the opportunities and challenges in planning and funding ATN systems and approaches for procuring ATN systems; and concludes with a summary of the existing challenges and opportunities for ATN technology. The study is intended to be an informative tool for planners, urban designers, and those involved in public policy, especially for urban transit, to provide a reference for history and background on ATN, and to use for policy development and research