Assist. Prof. Dr. Kerem Bayar

Mechanical Engineering Department
Middle East Technical University
B - 316
Tel: +90 312 210 5285
Email: kbayar@metu.edu.tr

Research Projects:

1) Tubitak 3501 Career Development Program. Opening for Three Students, 3000 TL/month scholarship available

Ride comfort is among the most important assessment criteria regarding automobiles and buses today. The current trend is usage of semi-active and active suspension systems for improving ride comfort. However, it is observed that the technology associated with these suspension systems have not matured yet. When the academic and the industrial literature regarding ride comfort is analyzed, it is seen that most studies focus on robust adaptive control strategies that optimizes ride comfort under different road surface roughness levels. Another hot research field in vehicle dynamics literature is control allocation approach, which aims at controlling the longitudinal, lateral and or vertical motion of the vehicle simultaneously and in a coordinated way. A pioneering version of such a coordinated control approach is observed in some production vehicles equipped with semi-active or active suspension systems. It is observed that stopping distance may be reduced for these vehicles by modifying the damping coefficient of the suspension actively in real time during ABS braking.

An active suspension system equipped with a linear electric motor will be developed in this project. The proposed active suspension system is a relatively new concept compared to the suspension systems utilizing hydro-pneumatic actuators. In this sense this project is considered to be the start-up project of the researcher, pursuing a long-term academic career in the field of vehicle dynamics and control. The active suspension control algorithm developed for controlling the motor will be tested with simulations first, prior to prototyping. The tire vertical stiffness and the sprung mass will be estimated in real time with the developed control algorithm. With this aspect, the control algorithm is hoped to contribute to the active suspension applications in the literature. Then the active suspension prototype developed and validated through simulations will be tested by a dynamic testing machine and a shaker. In these tests the suspension will be excited with not only specific frequencies and amplitudes, but also random inputs representing roughness of real road surfaces. The second unique aspect of the developed control algorithm is related to the testing of the two linear electric motors with hardware-in-the-loop simulations. Vehicle dynamics models developed with Matlab-Simulink will be loaded to the HIL simulator. Then two linear electric motors will be controlled with a control allocation algorithm with the objective of not only enhancing ride comfort, but also reducing vehicle roll and pitch motion during different maneuvers.

The control allocation developed has two unique aspects: Through a cost function embedded in the control allocator, excessive increase in wheel travel and suspension deflection will be avoided. By means road holding and handling will not be degraded. The second one is the feature of the control allocator during ABS and or ESP activation: The algorithm will allocate motor forces such that wheel load values that optimizes the performance of these features will be generated, this time without degrading ride comfort. The last step is mounting the electric motors to a real vehicle and testing them with road tests. The electric motors replaced with the conventional dampers of the rear suspensions will this time be controlled with the objective of enhancing ride comfort and reducing pitch. The outcome of this project would be quantified basically by the journal and conference publications at the end of each step summarized above, and the national patent application for the developed active suspension system.

Prerequisities: CUM GPA >= 3.2
ME 442, ME 429, ME 511, ME 513, ME 507, ME 520, ME 461, ME462
C programming and Matlab-Simulink Skills

2) Continuation of the Tubitak 2232 International Fellowship for Outstanding Researchers

The objective of this research is

a) Developing new "Active Motor Damping" control strategies for hybrid and electric vehicles. These would aim damping the vibrations on the hybrid powertrain during ABS and ESC activation.

b) Establishing a hardware-in-the-loop (HIL) simulation set-up that would have all components of the brake system of a hybrid or electric vehicle within a vehicle dynamics simulation scheme in laboratory environment.

Prerequisities: CUM GPA >= 3.2
ME 442, ME 429, ME 511, ME 513, ME 507, ME 520, ME 461, ME462, ME 466
C programming and Matlab-Simulink Skills


3) Comparison of Different Vehicle State Estimation Algorithms

This project aims at comparing vehicle state estimation algorithms utilizing different sets of sensors; wheel speed sensors, accelerometer and GPS. The estimation algorithms will be analyzed and tested in real time using a production vehicle.

Prerequisities: CUM GPA >= 3.2
ME 442, ME 511, ME 513, ME 507, ME 461, ME462
C programming and Matlab-Simulink Skills


4) Validation of the Mathematical Tire Model Using the Data Collected from the Tire Test Rig

The tire test rig will be operated with the aim of validating the mathematical tire model. The outputs of the tire model will be compared with the experimental results obtained from the test rig. By means the tire model will be parametrized for different automobile tires.

Prerequisities: CUM GPA >= 3.2
ME 513, ME 413, ME 465
Lab VIEW, C programming

Assist. Prof. Dr. Kerem Bayar short bio

Teaching:

ME 466 Performance of Road Vehicles, Senior Level Technical Elective Course: Spring 2016, 2017 and 2018 Semesters
ME 465 Automotive Engineering. Senior Level Technical Elective Course: Fall 2017, 2018 and 2019 Semesters.
ME 210 Applied Math for Mechanical Engineers. Sophomore Level Must Course: Spring 2017 Semester
ME 202 Manufacturing Technologies. Sophomore Level Must Course: Fall 2016, Spring 2018, Spring 2019 Semesters.
ME 212 Principles of Production Engineering. Sophomore Level Must Course: Fall 2017, Fall 2018 and Spring 2020 Semesters.
ME 301 Theory of Machines 1: Junior Level Must Course: Fall 2019 Semester
ME 302 Theory of Machines 2: Junior Level Must Course: Spring 2020 Semester

Industry Experience:

2014-2015: Ford Stability Control group, Chassis Organization, Ford Motor Company, Dearborn, Michigan, USA.
2011-2014: Ford College Graduate Program, Ford Motor Company, Dearborn, Michigan, USA. Six months long rotations in five different groups:
1) Regenerative Braking Group in Chassis organization.
2) Vehicle Controls and Systems Engineering Group in Research and Advanced Engineering organization.
3) Electric Motor Controller group in Electrified Powertrain Engineering organization.
4) Michigan Assembly Plant.
5) Ford Stability Control Group in Chassis organization.

Educational Background:

2007-2011 : PhD, Mechanical Engineering Department, The Ohio State University. GPA: 3.86/4
Dissertation title: Development of a Vehicle Stability Control Strategy for a Hybrid Electric Vehicle Equipped With Axle Motors

2004-2006 : MS, Mechanical Engineering Department, Middle East Technical University. GPA: 3.92/4
Thesis title: Modeling of the Dynamics of Multi-Axle Steered Vehicles.

2000-2004 : BS, Mechanical Engineering Department, Middle East Technical University. GPA: 3.24/4

SCI Journal Publications

1 BAYAR, K. 2020 Performance Comparison of Electric-vehicle Drivetrain Architectures from a Vehicle Dynamics Perspective Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, DOI: https://doi.org/10.1177/0954407019867491

2 BAYAR, K., WANG, J. and RIZZONI, G 2012 Development of a vehicle stability control strategy for a hybrid electric vehicle equipped with axle motors Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering DOI: 10.1177/0954407011433396.

3 BAYAR K., BIASINI R., ONORI S. and RIZZONI G. 2012 Modelling and control of a brake system for an extended range electric vehicle equipped with axle motors International Journal of Vehicle Design, DOI: 10.1504/IJVD.2012.047387.

4 BAYAR, K., and UNLUSOY, Y., S. 2008 Steering Strategies for Multi-Axle Vehicles, International Journal of Heavy Vehicle Systems, DOI: 10.1504/IJHVS.2008.022243.

5 BAYAR, K. 2020 Active Motor Damping Strategies for Hybrid and Electric Vehicles,in preparation.

Other Journal and Conference Publications

1 BAYAR, K. ve SADEGHI-KHANEGHAH, F. 2020 Optimal Sliding Mode Control Method for Active Suspension Control, accepted to International Federation of Automatic Control (IFAC) World Congress, to be held in Berlin, July 2020.

2 BAYAR, K., MCGEE, R., YU, H., ve CROMBEZ, D., 2013 Regenerative Braking Control Enhancement for the Power Split Hybrid Architecture with the Utilization of Hardware-in-the-loop Simulations, SAE International Journal of Alternative Powertrains, DOI:10.4271/2013-01-1466.

3 BAYAR, K., BEZAIRE B, COLEY B, KRUCKENBERG J, SCHACHT E, MIDLAM-MOHLER S ve RIZZONI G. 2010 Design of an Extended-Range Electric Vehicle for the EcoCAR Challenge ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. No. DETC2010-28927, sayfa. 687-700; DOI:10.1115/DETC2010-28927.

4 BAYAR, K., ve ARNETT, M. 2008 Modeling and Testing of a Traction Control System Applied to the Challenge X Competition Vehicle, SAE All-Wheel Drive Vehicle Symposium, Agustos, 20-22, 2008, Ypsilanti, Michigan, Amerika Birlesik Devletleri.

5 BAYAR, K. 2018 Comparison of Different Electric Vehicle Drivetrain Architectures from a Vehicle Dynamics Standpoint [in TR] OTEKON 2018; 9th International Automotive Technologies Congress, 7-8 May, 2018, Bursa, Turkiye.

6 BAYAR, K., ve UNLUSOY, Y., S. 2006 Modeling of the Dynamics of Multi-Axle Steered Vehicles OTEKON 06; 3. Otomotiv Teknolojileri Kongresi, Haziran, 26-28, 2006, Bursa, Turkiye.