Deniz Korkmaz

Modeling and implementation of a biomimetic robotic fish

In this study, design and implementation of a remote-controlled, 4-joints flapping mechanism and autonomous-swimming biomimetic robotic fish are presented. The propulsive model of the robotic fish is given considering the biological fish structure. The motion control of the robotic fish is performed by using speed and position control. The forward speed of the robotic fish can be adjusted by changing oscillation frequency, oscillation amplitude and length of the oscillation mechanism. Its position is controlled by implementing different joints angles.

Extreme learning machine based robotic arm modeling

Robotic arms are very powerful machines that can be used in many various applications in industry. So that, a suitable dynamic model is derived to verify that performs the tasks. But, dynamic equation is an important issue due to its complexity. Thus, an alternative model can be derived for the robotic arms. This paper is proposed Extreme Learning Machine (ELM) model for the angular acceleration of a robotic arm. The performance of the ELM model is performed by using Pumadyn datasets. At the same time, the validation of the proposed model is compared with Artificial Neural Network (ANN). Experimental results show that the proposed model is suitable and it provides low computation complexity.

Dynamic simulation model of a biomimetic robotic fish with multi-joint propulsion mechanism

In this paper, a biomimetic carangiform robotic fish is analysed based on dynamic and kinematic models. The carangiform fish can swim with features like high mobility, fast swimming and changing direction suddenly. Because it has these amazing features, a carangiform swimmer is modelled. Dynamic and kinematic models are analytically obtained to design a biomimetic carangiform robotic fish. The designed robotic fish consists of two parts: an anterior rigid body and a flexible tail, which is modelled as a four-joint propulsion mechanism, and each joint is driven by a servo motor. The dynamic model is developed in the MATLAB/Simulink environment using a Lagrange function and the state-space model is performed to linearize the obtained model. Each joint is controlled with conventional PID controller in the simulation. Furthermore, a solid model of the robotic fish prototype is drawn in SolidWorks and transferred to the MATLAB/Simmechanics environment, and the motion of the robotic fish is simulated using joint angles. Finally, experimental studies and simulation results show that a carangiform motion for autonomous swimming is developed and verified using controlled joint angles.

DYNAMIC MODEL AND SIMULATION OF ONE ACTIVE JOINT ROBOTIC FISH

This study considers the dynamic model of one active joint robotic fish by using Lagrange method and simulation of the robotic fish model in MATLAB/SimMechanics environment. Compared results of these two different models are given in the study. The mathematical model of the system is derived from Lagrange energy equations of the robotic fish inspired from a real carangiform fish. The Computer Aided Design (CAD) model of the robotic fish is designed by using SolidWorks and it is transferred to the SimMechanics environment. The hydrodynamic effects, which are linear and nonlinear drag force, are also adapted and head motion, one active joint, and one passive joint angles found by using MATLAB Simulink environment. Obtained results for joint angles from both dynamic and SimMechanics models are compared and proved with animation video of the robotic fish.

Modeling of inverted pendulum on a cart by using Artificial Neural Networks

In this study, mathematical model of the single bar inverted pendulum on a cart, which exhibits similar behavior to the dynamics of a robotic arm, is derived by using Lagrange method. At the same time, nonlinear model of the inverted pendulum is simulated in MATLAB environment by using Multilayer Artificial Neural Networks (MANN). MANN is trained by back propagation learning algorithm and dynamic NARX network model is selected for MANN. This model is the basis for dynamics of the robotic arm.

Motion Control of Three-Rotor Unmanned Underwater Vehicle

This paper presents the design of a three-rotor Unmanned Underwater Vehicle (UUV) and generating nonlinear mathematical model. The main propose of this design is to adapt to the UUV effective propellers. For this purpose, three-rotor model is aligned to the Center of Gravity (CoG) and UUV can move in three dimensional space. The derived mathematical model includes the kinematics, dynamics and hydrodynamics effects acting on the body. In order to achieve 6-DoF motion control, three-layered control structure is designed and generalized linear/angular positions and velocities are examined. In addition, three dimensional circular trajectory tracking is performed to achieve effective motion responses.

Design and Control of Diving Mechanism for the Biomimetic Robotic Fish

This paper focuses on generating nonlinear mathematical model of the robotic fish and design a novel diving mechanism for the robotic fish prototype. For this purpose, diving behavior of a real fish is analyzed by using Kineova 8.20. The designed diving mechanism model is constructed by using moving of the sliding mass and dynamic model of robotic fish behavior is performed completely. The diving mechanism is also rearranged by adapting to the robotic fish prototype in order to obtain simple and better design performance. Hence, three dimensional motions results are obtained by using the nonlinear mathematical model and diving mechanism of the robotic fish with different diving angles.

Link length optimization of a biomimetic robotic fish based on Big Bang — Big Crunch algorithm

This paper is concerned with the link length optimization method of a biomimetic Carangiform robotic fish with multi-link propulsion mechanism. Motion characteristic of a real fish depends on the body traveling wave and propulsion mechanism of the robotic fish should imitates the traveling wave function. In order to imitate the body traveling wave with minimum error, intersection method is used and Big Bang - Big Crunch (BB-BC) optimization algorithm is adapted to this method. BB-BC algorithm is a heuristic and evolutionary optimization method. BB-BC is preferred in many nonlinear engineering problems because of the low computation time and very fast convergence speed. As a results, optimum link lengths and endpoints of the each joint are determined by using this combined method. Numerical results show that precise fitting effects and link length optimization can improve the propulsion efficiency of the robotic fish. Also, optimum links are proportioned according to actual size of a real Carangiform carp fish in the main axis and free swimming gaits of the real carp are proved.

Design and Implementation of A Single-Stage Full-Bridge DC/DC Converter with ZVS Mode

In this paper, a single-stage full-bridge converter with auxiliary circuit elements which allow its main power circuit switches to operate with ZVS mode is presented. By creating dead time between power switches and working across, high frequencies which are the basis of the soft-switching are reached. Thus, more uniform output of system is obtained. In addition, it is observed that output rectifier diodes are exposed to parasitic oscillations. Experimental results obtained from the prototype with DC 180V input voltage, DC 45V output voltage and 50kHz operation frequency are illustrated in the paper.