Vasfi Emre Ömürlü

Modeling the Dynamics and Kinematics of a Telescopic Rotary Crane by the Bond Graph Method: Part II

Cranes employed for load transfer are large volume machines and canbe designed to accomplish linear, planar or spatial motions dependingon the intended use. Understanding the dynamic behavior of thesesystems, which have a load-carrying capacity of hundreds of tonnes, ishighly noteworthy for system design, control, and work safety. Inthis study, a theoretical model of a spatially actuated telescopic rotarycrane is obtained with provided assumptions using Bond Graph techniques.Following the modeling of an actuation system and of a main structure,unification of these two is accomplished. Since the overall system consistsof high nonlinearity originating from geometric nonlinearity, gyroscopicforces, hydraulic compressibility, and elastic boom structure, the resultingderivative causality problem caused by rigidly coupled inertia elementsis addressed for this highly nonlinear system and consequential systemstate-space equations are presented.

Modeling of a Coupled Industrial Tank System with ANFIS

Since liquid tank systems are commonly used in industrial applications, system-related requirements results in many modeling and control problems because of their interactive use with other process control elements. Modeling stage is one of the most noteworthy parts in the design of a control system. Although nonlinear tank problems have been widely addressed in classical system dynamics, when designing intelligent control systems, the corresponding model for simulation should reflect the whole characteristics of the real system to be controlled. In this study, a coupled, interacting, nonlinear liquid leveling tank system is modeled using ANFIS (Adaptive-Network-Based Fuzzy Inference System), which will be further used to design and apply a fuzzy-PID control to this system. Firstly, mathematical modeling of the system is established and then, data gathered from this model is employed to create an ANFIS model of the system. Both mathematical and ANFIS model is compared, model consistencies are discussed, and flexibility of ANFIS modeling is shown.

A novel visualization technique in Bond-Graph method for modeling of a generalized stewart platform

This paper represents dynamic modeling of generalized stewart platform manipulator by Bond Graph method with a new spatial visualization method and the state-space representation of the dynamic equations of the system. Dynamic model includes all the dynamics and gravity effects, linear motor dynamics as well as the viscous friction at the joints. Following modeling of actuation system and of main structure, unification of these two is accomplished. Linear DC motors are utilized and modelled as the actuation system. Since overall system consists of high nonlinearity originated from geometric nonlinearity and gyroscopic forces, resultant derivative causality problem caused by rigidly coupled inertia elements is addressed and consequential system state-space equations are presented.

A robust single input adaptive sliding mode fuzzy logic controller for automotive active suspension system

The proposed controller in this paper, which combines the capability of fuzzy logic with the robustness of sliding mode controller, presents prevailing results with its adaptive architecture and proves to overcome the global stability problem of the control of nonlinear systems. Effectiveness of the controller and the performance comparison are demonstrated with chosen control techniques including PID and PD type self-tuning fuzzy controller on a quarter car model which consists of component-wise nonlinearities.

Development of a MEMs-based IMU Unit

In this study, gyroscope-free inertial measurement unit interface is developed to simulate new system configurations called YILDIZ using known calculation methods and implementation of MEMS accelerometers based on cubic arrangement. Additionally significant effect of different sensing directions and sensor allocations are taken into consideration. Throughout the project, simulation studies, realization of sample gyro-free MEMs-based INS systems, and collection of data through data acquisition systems are performed in given order. Using simulation of the system, parameter-dependent errors are aimed to be minimized on the system output. Then, near-ideal geometry and the sensor configurations can be reached and the system can be realized. Prototype outputs are processed and efficient algorithms are developed using Matlab-Simulink environment.

Nonlinear state-space representations of a quadrotor through bond-graph technique

Obtaining efficient dynamic equations of complex systems, like processes or robotic systems, are very important for control system design. While various forms of acquiring motion equations exist, state-space form has its advantages for analyzing complex systems. Among analytical and graphical techniques of finding dynamic behavior of a system, bond-graph provides straight forward way of serving linear/nonlinear equations of systems in state-space form. In this study, a four-propeller-actuated full/reduced order quadrotor spatial dynamics are investigated by using bond-graph technique. Full order dynamic behavior is obtained including motor, gear, shaft, propellers and the body. Additionally, neglecting motor dynamics, reduced order state-space representations of the system is also provided, assuming force/moment input and propeller speed as inputs to the vehicle separately. Responses of the models are compared and discussed.

A Stewart Platform as a FBW Flight Control Unit

A Stewart Platform as a FBW Flight Control Unit A variety of flight control units have been put into realization for navigational purposes of spatially moving vehicles (SMV), which is mostly manipulated by 2 or 3 degrees-of-freedom (DOF) joysticks. Since motion in space consists of three translational motions in forward, side and vertical directions and three rotational motions about these axis; with present joystick interfaces, spatial vehicles has to employ more than one navigational control unit to be able to navigate on all required directions. In this study, a 3 × 3 Stewart-Platform-based FBW (Fly-By-Wire) flight control unit with force feedback is presented which will provide single point manipulation of any SMVs along three translational and about three rotational axis. Within the frame of this paper, design, capability and the advantages of the novel system is mentioned. Kinematics of a Stewart Platform (SP) mechanism employed and its motion potentials is presented by simulations and workspace of the system is evaluated. Dynamic analysis by Bond-Graph approach will be mentioned. Mechatronic design of the complete structure is discussed and force reflection capability of the system with simulations is pointed out using stiffness control. Finally, the possible future work of the subject is discussed which may include the feasible solutions of the SP in terms of size and safety when implementing inside a cockpit.

A stewart platform as a FBW flight control unit for space vehicles

A variety of flight control units have been put into realization for navigational purposes of spatially moving vehicles, which is mostly manipulated by 2–3 degrees-of-freedom (DOF) joysticks. Since motion in space consists of three translational motions in forward, side and vertical directions and three rotational motions about these axis; with present joystick interfaces, spatial vehicles has to employ more than one navigational control unit to be able to navigate on all required directions. In this study, a 3×3 Stewart-Platform-based FBW (Fly-By-Wire) flight control unit with force feedback is presented which will provide single point manipulation of any space vehicle performing spatial motions along three translational and three rotational axis. Within the frame of this paper, design, capability and the advantages of the novel system is mentioned. Kinematics of the Stewart Platform (SP) mechanism employed and its motion potentials is presented by simulations and workspace of the system is evaluated. Dynamic analysis by Bond-Graph approach will be mentioned. Mechatronic design of the complete structure is discussed and force reflection capability of the system with simulations is pointed out using stiffness control. Finally, the possible future work of the subject is discussed which may include the feasible solutions of the SP in terms of size and safety when implementing inside a cockpit.

Workspace analysis of parallel mechanisms through neural networks and genetic algorithms

Stewart Platform Mechanism (SPM) is a type of parallel mechanism (PM) which has 6 degrees of freedom. Due to features like precise positioning and high load carrying capacity, PMs have been used in many areas in recent years. But relatively small workspace of the mechanism is the major disadvantage. This paper aims to improve the method for PM workspace analysis. The structure of Artificial Neural Network (ANN) which was used to analyze 6×3 SPMs workspace, is determined by Genetic Algorithms (GA). This structure of ANNs, i.e., weights, biases are very effective on catching highly accurate results of the ANNs. Therefore, calculation of these values and appropriate structure, i.e., number of neurons in hidden layers, by trial and error approach, results in spending too much time. To prevent the loss time and to determine the problem most fitted structure of hidden layers, a GA is developed and tested in simulation environment, i.e., software developed data. It is noted that by using software-calculated-parameters instead of using trial-error-approach parameters gives the user as accurate as trial-error-approach in short time span.

Modeling of an accelerometer-based inclinometer by artificial neural networks

In this study, dynamic modeling of an accelerometer based inclinometer is carried out. Empirical methods are used in order to obtain the model of the system and an experimental setup is designed and constructed to realize the required experiments. Classical system identification and neural network methods are used to acquire the dynamic models. Since, accelerometers/inclinometers are commonly used in spatially moving vehicles; simulation models of these are needed. Taking advantage of this dynamic model, the simulation results, which include accelerometers/inclinometers, can become more realistic and extensive filtering techniques would work more efficiently with better sub-system models.