Browsing by Author "Temiz, Ozan"

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Open Access
Development of control oriented vehicle models and their application to adaptive control allocation problems
(2018-09) Temiz, Ozan
Emerging vehicle control systems have increased the need for valid vehicle models. In this study, two controller oriented vehicle models are developed and linearized for easier controller design. These models are validated by using an advanced vehicle simulation commercial suite. Then by using these models, an adaptive, fault-tolerant control allocation method which simultaneously commands all traction and steering related actuators is developed. The proposed control scheme consists of a high level controller that creates a virtual control input vector and a low level control allocator that distributes the virtual control effort among redundant actuators. Virtual control input consists of desired forces and moments to ensure stability while following a given reference. Based on this virtual control input vector, the allocation module determines actuator inputs. Performance of the proposed system is evaluated via an object avoidance maneuver in various scenarios such as different velocities and effectiveness loss at actuators. Results show that the proposed approach can follow the references despite the loss of actuator effectiveness in the driving cycle.
Open Access
A fault tolerant vehicle stability control using adaptive control allocation
(ASME, 2018) Temiz, Ozan; Çakmakçı, Melih; Yıldız, Yıldıray
This paper presents an integrated fault-tolerant adaptive control allocation strategy for four wheel frive - four wheel steering ground vehicles to increase yaw stability. Conventionally, control of brakes, motors and steering angles are handled separately. In this study, these actuators are controlled simultaneously using an adaptive control allocation strategy. The overall structure consists of two steps: At the first level, virtual control input consisting of the desired traction force, the desired moment correction and the required lateral force correction to maintain driver’s intention are calculated based on the driver’s steering and throttle input and vehicle’s side slip angle. Then, the allocation module determines the traction forces at each wheel, front steering angle correction and rear steering wheel angle, based on the virtual control input. Proposed strategy is validated using a non-linear three degree of freedom reduced two-track vehicle model and results demonstrate that the vehicle can successfully follow the reference motion while protecting yaw stability, even in the cases of device failure and changed road conditions.
Open Access
Integrated vehicle control using adaptive control allocation
(John Wiley & Sons Ltd., 2023-04-28) Temiz, Ozan; Çakmakçı, Melih; Yıldız, Yıldıray
The focus of this paper is an integrated, fault-tolerant vehicle control algorithm for the overall stability of ground vehicles. The proposed scheme comprises a high-level controller that creates a virtual control input and a low-level adaptive control allocator that distributes the virtual control effort among redundant actuators. The proposed control framework distinguishes itself from earlier results in the literature by its ability to blend active suspension, steering and traction control channels, in the presence of uncertainties and time-varying dynamics, without the need for fault identification. The control structure is validated in the simulation environment using a fourteen-degree-of-freedom non-linear vehicle model. The integrated controller is compared to the case of a conventional control approach where each control problem is solved separately. Our results show that, compared to the conventional approach, the proposed method ensures that the vehicle follows driver inputs with up to % higher longitudinal maneuver velocity, despite the presence of actuator failures and slippery road conditions. Furthermore, to demonstrate the benefit of integrating active suspension control to the overall control scheme, we replaced the suspension control of the proposed approach with an independent suspension control system for comparison purposes. We then showed that the integrated case provided % lower roll angle deviation, and % lower pitch angle deviation, in the presence of actuator effectiveness loss and adverse road conditions.
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TEMA fikri : kuruluşu, başarıları ve başa çıkılan zorluklar
(Bilkent University, 2014) Temiz, Ozan; Akın, Utku; Aşlakçı, Safa; Sezer, Batuhan