Attenuation of the adverse effects of vehicle vibrations on human health is a challenging problem. One common approach to solve this problem is to use various types of controllers in vehicle suspensions. In this study, in order to decrease the vehicle vibrations and hence improve the ride comfort, a fuzzy logic integrated sliding mode controller was designed. The performance of the controller was tested in a biodynamic human-vehicle combined model. The human body was considered as a lumped parameter model and incorporated into a full vehicle model. The biodynamic responses of a human body to vehicle vibrations were analyzed. Performances of the conventional sliding mode and fuzzy integrated sliding mode controllers were compared with those of a passive control strategy. According to the numerical results, the fuzzy sliding mode controller overcame both classic sliding mode and passive control approaches and decreased vehicle vibrations considerably. It can be deduced from the study that active suspension systems would play a key role in decreasing the negative effects of vehicle vibrations on human health, such as motion sickness, discomfort and spine injuries.

We design a controller for flow-induced vibrations of an infinite-band membrane, with flow running across the band and only above it, and with actuation only on the trailing edge of the membrane. Due to the infinite length of the membrane, the dynamics of the membrane in the spanwise direction are neglected, namely, we employ a one-dimensional (1D) model that focuses on streamwise vibrations. This framework is inspired by a flow along an airplane wing with actuation on the trailing edge. The model of the flow-induced vibration is given by a wave partial differential equation (PDE) with an antidamping term throughout the 1D domain. Such a model is based on linear aeroelastic theory for Mach numbers above 0.8. To design a controller, we introduce a three-stage backstepping transformation. The first stage gets the system to a critically antidamped wave equation, changing the stiffness coefficient's value but not its sign. The second stage changes the system from a critically antidamped to a critically damped equation with an arbitrary damping coefficient. The third stage adjusts stiffness arbitrarily. The controller and backstepping transformation map the original system into a target system given by a wave equation with arbitrary positive damping and stiffness.

3B baskı teknolojilerinden biri olan ergiterek yığma ile modelleme (FDM) üretim teknolojisi ve polilaktik asit (PLA) malzemesi kullanarak farklı dolgu deseni ve yönüne sahip çekme testi numuneleri üretilmiş ve dolgu deseni ve yönünün çekme dayanımına olan etkileri incelenmiştir. Beş farklı dolgu deseni (eş merkezli, ızgara, üçgen, 3B altıgen, zik zak) ve üç farklı dolgu desen açısına (0°, 45°, 90°) sahip aynı ağırlıkta 10 adet numune ve bir adet de tam dolu numune FDM teknolojisi ile basılarak toplam 11 adet numune üretilmiştir. Tüm numunelere mekanik çekme testi uygulanmıştır. Mekanik çekme testi sonucunda; ikinci numunenin (90° dolgu desen açılı, eş merkezli), aynı ağırlıktaki diğer numunelere göre daha yüksek dayanıma sahip olduğu tespit edilmiştir. Eş merkezli numunenin aynı ağırlıktaki diğer numunelere göre dayanımının yüksek olması, baskı desen yönünün çekme yönüyle bağlantılı olduğu ve dolayısıyla baskı sırasında baskı desen açılarının ve yönlerinin uygulanan kuvvetler doğrultusunda seçilmesinin büyük avantaj sağladığı görülmüştür. Ayrıca, %30 doluluk oranındaki ikinci numunenin %100 doluluk oranına sahip birinci numuneye göre özgül dayanımının yaklaşık %25 oranında daha yüksek olduğu çekme testi sonucunda gözlemlenmiştir. Bu nedenle parçaların çalışma şartlarında maruz kaldıkları yüklenme durumları dikkate alınarak tam dolulukla basılmış parçalarla aynı dayanıma sahip daha hafif ve daha az maliyetli tasarımların yapılabileceği sonucu ortaya çıkmıştır.

Mobile robot concept is one of the most commonly used nonholonomic system for industrial and academic autonomous applications. There are many types of mobile robot design concepts and control strategies which have been continuously developed by researchers. In this study, two wheeled differential drive mobile robot (DDMR) is used for trajectory tracking study under different conditions. Reference trajectory, dynamic and kinematic motion models of DDMR are defined as mathematical expressions in computer software. For tracking the reference trajectory, error between current pose and reference pose was decreased by sliding mode controller (SMC) and proportional–integral–derivative controller (PID) with kinematic based backstepping controller (KBBC) respectively. A reference path which consists of sinusoidal and linear parts tracked by both controller combinations in first simulation to examine controller tracking performances. In order to examine and compare; responsiveness, stability and robustness of the controllers, an additional mass which affects motion dynamics of DDMR vertically added to the mobile robot body during trajectory tracking application. All results and discussions are comparatively stated at the end of the study with related error figures and evaluations.

In this study, PID based efficient control systems are designed and compared for position control of a quadcopter in six degrees of freedom. The main goal is to get the quadcopter to the desired position in three-dimensional space. Firstly, the desired position for the quadcopter to reach is determined. Then, the physical model of the system is selected, and mathematical model is derived according to the physical model. Initially, all external disturbances like drag force and wind are neglected. However, various external disturbances are then applied to the system to measure robustness of the designed controllers. Firstly, PID controller is implemented to the quadcopter system. Secondly, Fuzzy-PID controller is used. Necessary pitch and roll angles are found and control forces are calculated by using both controllers. Also, angular velocities of the motors and current values which are needed to be supplied to each motor are calculated and compared to evaluate performance and applicability of the proposed controllers. According to the results, it is observed that both controllers worked successfully, quadcopter is able to reach the desired location in three-dimensional space. However, Fuzzy-PID controller gives faster response and smaller overshoot levels than basic PID controller. In addition, it is seen that the Fuzzy-PID controller is less affected by external disturbances, and it recovers faster against these changes.