Browsing by Author "Emirler, Mumin Tolga"

Now showing 1 - 8 of 8

Citation Count: 0
Communication Disturbance Observer Approach to Control of Integral Plant with Time Delay
(Ieee, 2013) Emirler, Mumin Tolga; Guvenc, Bilin Aksun; Guvenc, Levent
The presence of time delay can cause stability problems in closed loop systems as it adds large negative phase angle to the system frequency response. The Smith predictor is a well-known method of dealing with fixed and known time delays in control systems. Errors in the knowledge of the time delay will cause degradation of the Smith predictor compensation performance. A solution to this problem is to use a communication disturbance observer. Time delayed integral plants are typical examples of open loop unstable systems with time delay. In this paper, the communication disturbance observer based time delay compensation method is applied to high order time delayed integral plants. A robust stability condition is derived for time delayed feedback control systems with the communication disturbance observer. The effect of the communication disturbance observer Q filter cut-off frequency selection on robust stability is investigated. Simulation results are presented for both constant and time varying delays to illustrate the effectiveness of the proposed communication disturbance observer approach.
Citation Count: 1
Comparison of Different Time Delay Compensation Methods for Networked DC Motor Speed Control
(Ieee, 2019) Suulker, Cem; Emirler, Mumin Tolga
In this paper, different time delay compensation methods are applied to networked DC motor speed control such as Smith predictor, communication disturbance observer (CDOB), double disturbance observer (DDOB). The PI speed control system structures augmented with these methods are introduced. The reference tracking and external disturbance rejection performance of these methods are evaluated by simulations and experiments. The integral absolute error (IAE) criterion is used to assess performance numerically. Simulation and experimental results prove the effectiveness of DDOB over the other methods.
Citation Count: 25
Design and Evaluation of Robust Cooperative Adaptive Cruise Control Systems in Parameter Space
(Korean Soc Automotive Engineers-ksae, 2018) Emirler, Mumin Tolga; Guvenc, Levent; Guvenc, Bilin Aksun
This paper is on the design of cooperative adaptive cruise control systems for automated driving of platoons of vehicles in the longitudinal direction. Longitudinal models of vehicles with simple dynamics, an uncertain first order time constant and vehicle to vehicle communication with a communication delay are used in the vehicle modeling. A robust parameter space approach is developed and applied to the design of the cooperative adaptive cruise control system. D-stability is chosen as the robust performance goal and the feedback PD controller is designed in controller parameter space to achieve this D-stability goal for a range of possible longitudinal dynamics time constants and different values of time gap. Preceding vehicle acceleration is sent to the ego vehicle using vehicle to vehicle communication and a feedforward controller is used in this inter-vehicle loop to improve performance. Simulation results of an eight vehicle platoon of heterogeneous vehicles are presented and evaluated to demonstrate the efficiency of the proposed design method. Also, the proposed method is compared with a benchmark controller and the feedback only controller. Time gap regulation and string stability are used to assess performance and the effect of the vehicle to vehicle communication frequency on control system performance is also investigated.
Citation Count: 4
Disturbance Observer Based Active Independent Front Steering Control for Improving Vehicle Yaw Stability and Tire Utilization
(Korean Soc Automotive Engineers-ksae, 2022) Gozu, Murat; Ozkan, Basar; Emirler, Mumin Tolga
In the currently used steering systems, the front tires are steered dependently during turning maneuvers. During these maneuvers, the weight transfer causes the inner tire to have less vertical force compared to the outer tire. Therefore, it generates less lateral tire force and can be saturated easily in some extreme conditions. On the other hand, the outer tire can provide more lateral force due to the higher vertical force, but its potential may not be utilized because the steering of the inner and outer tires is dependent. Thus, an independent steering capability can provide potential benefits by eliminating the saturation of the inner tire and getting more lateral force from the outer tire. Therefore, an active independent front steering system is proposed by combining a yaw-rate PI controller with disturbance observers on tire forces to improve the yaw stability at the acceptable limits. The coefficients of the PI controller are calculated analytically. The cut-off frequency in the disturbance observer is determined by the robust stability analysis considering the variance in the vehicle dynamic parameters. Finally, by taking into account the tire utilization coefficient (TUC), the performance of the proposed system is compared to conventional active steering systems in CarSim simulation environment.
Citation Count: 2
Lateral Stability Control of Articulated Heavy Vehicles Based on Active Steering System
(Engineering & Technology Publishing, 2022) Emheisen, Mustafa A.; Emirler, Mumin Tolga; Ozkan, Basar
The main purpose of this paper is to design a controller for improving the lateral stability of long heavy vehicle combinations based on active steering system. An augmented optimal linear quadratic control system design is implemented. The controller is developed and evaluated with step and lane change maneuvers for a truck and trailer combination. The uncertainties masses of the truck and trailer are taken into account for analysis purpose. The nonlinear and linear model of the truck and trailer are presented. The simulation results show a decrease in yaw rate rearward amplification and sideslip angles significantly with successful desired yaw rate tracking for the trailer.
Citation Count: 3
Multi-objective parameter space approach based controller and add-on disturbance observer design
(Korean Soc Mechanical Engineers, 2017) Emirler, Mumin Tolga; Guvenc, Bilin Aksun
The parameter space approach based robust PI control design methodology for DC motor speed control is proposed in this paper. The multi-objective design requirements like D-stability, phase margin and mixed sensitivity ( frequency domain) bounds are mapped into the controller parameter space to determine PI controller coefficients which satisfies the desired user-defined specifications. Besides robust PI controller, an add-on disturbance observer is utilized to enhance the tracking performance and disturbance rejection of the control system. The proposed control scheme is validated by simulations and experiments. The results prove that the effectiveness of the proposed control system against uncertainties in the modeling and disturbances on the system response.
Citation Count: 4
Vehicle dynamics modelling and validation for hardware-in-the-loop testing of electronic stability control
(inderscience Enterprises Ltd, 2016) Emirler, Mumin Tolga; Uygan, Ismail Meric Can; Gelbal, Sukru Yaren; Gozu, Murat; Boke, Tevfik Ali; Guvenc, Bilin Aksun; Guvenc, Levent
Hardware-in-the-loop (HiL) simulation is used to test code changes in automotive control systems for component tests and for fault testing. A realistic and validated vehicle dynamic model needs to be used in the simulations. The experimental and simulated results should exhibit a close match in a validation study. The development of a validated CarSim model of a light commercial vehicle for use in HiL simulation is presented in this paper. A CarSim dynamics model has been prepared for a light commercial vehicle and validated using driving test data obtained on a test track. The HiL simulator developed for testing the electronic stability control unit of this vehicle is presented along with results of an exemplary HiL simulation.
Yanal performansı artırmak için çekici – treyler ağır vasıtalarının aktif yönlendirme kontrolü
(2022) Emheısen, Mustafa Abdalwafı Abasalam; Özkan, Başar; Emirler, Mumin Tolga
Çekici – treyler ağır vasıtaları daha az yakıt tüketmesi ve sürücü maliyetlerinin daha az olması nedeniyle günümüzde yaygın bir biçimde kullanılmaktadır. Tasarımın zayıf yapıldığı çok üniteli taşıtlarda, sürüş kararsızlığı ve devrilme problemleri ile karşılaşılabilmektedir. Yüksek hızlarda, çekici – treyler ağır vasıtaları üç temel nedenden ötürü kararlılığını yitirebilmektedir: treyler dönüşü, treylerin çekici üzerine katlanması ve devrilme. Bu tip problemlerin önüne geçmek, taşıtın performansının artırmak ve kararlılığını sağlamak için, kontrol sistemleri önemli bir rol oynamaktadır. Aktif yönlendirme kontrolü için üç kontrol metodu uygulanmıştır. Bunlar PID, LQR ve MPC kontrol yaklaşımlarıdır. Bu tezde önerilen kontrol sistemlerinin test edilmesi için, altı farklı senaryo üzerinde çalışmalar yürütülmüştür. Birim basamak ve sinüs şeklinde direksiyon girişi çok üniteli taşıt kombinasyonuna uygulanmıştır. Çekici ve treyler kütlelerindeki belirsizlikler dikkate alınmıştır. Belirsizliklerin dikkate alınmasındaki amaç kontrol sistemlerinin daha gerçekçi koşullarda test edilmesini sağlamak ve savrulma açısal hızı kontrolüne belirsizliklerin etkisinin incelenmesidir. Ayrıca, bazı senaryolarda bozucunun ve eyleyici kısıtlarının kontrol sistemi performansına etkisi irdelenmiştir. Geriye doğru savrulma açısal hızı yükseltimi, çekici – treyler ağır vasıtalarının yanal performansının iyi bir göstergesidir. Önerilen kontrol sistemleri, geriye doğru savrulma açısal hızı yükseltimini azaltacak ve treyler dönüşü ile treyler devrilmesini önlemek için yanal ivmeyi sınırlandıracak şekilde tasarlanmıştır. Tüm benzetim sonuçları kontrol girişleri, savrulma açısal hızı, yanal ivme, yana kayma açısı, basamak cevap karakteristikleri, takip edilen yörüngeler ve geriye doğru savrulma açısal hızı yükseltimi açısından birbirleriyle karşılaştırılmıştır.