In this thesis, the inertial parameters of a spatial mechanism are used in order to optimize various aspects of the dynamic behaviour of the mechanism (such as minimizing actuator torque/ force fluctuations, shaking force/moment balancing, etc.) while the effects of loads are considered as well. Here, inertial parameters refer to the mass, 6 elements of the inertia tensor and coordinates of the center of mass of the links. The concept of Force Fluctuation Number (FFN) is utilized to optimize the dynamic behaviour of the mechanism. By using the FFN concept, one obtains a number of linear equations to be satisfied by the optimal inertial parameters. In general, the number of such equations is less than the number of the inertial parameters. Therefore, some of the inertial parameters may be selected freely in order to satisfy other design constraints. Using MATHEMATICA, a program has been developed to obtain the linear equations to be satisfied by the optimal inertial parameters. The developed program includes a kinematic and force analysis module, which can be used independently for a complete kinematic and dynamic analysis of any one degree of freedom, single loop, spatial mechanism. The different closures of the mechanism may be identified by using the developed package and these analyses can be performed on any selected closure of the mechanism.

Design, production and development of individual mini/micro robots and then formation of their cooperative colony are the main topics of this thesis. The produced mini/micro robots are as small and light as possible. In addition, they are multifunctional (programmable), flexible and intelligent while maintaining a very low production cost. Mini/micro robots, called MinT-DB series are able to communicate with each other to work cooperatively. Moreover, these robots can be the basis for the future studies considering the application of artificial intelligence and modeling of live colonies in the nature. Traditional design, production and assembly techniques have been used widely up to now. However, none of them were related with the mini/micro scale. Therefore, this thesis can help people in understanding the difficulties of the design, production, and assembly of the mini/micro systems under the light of the reported science. In this thesis, instead of examining a specific application field of mini/micro robotic systems, a technology demonstrative work is carried out. Therefore, this thesis contributes to the mini/micro robotic technology, which is also very new and popular in today&amp / #8217 / s world, with the robots having the dimensions of 7.5x6x6 cm.

The aim of this study is to obtain optimal position and orientation of a trajectory frame with respect to the fixed frame of the manipulator. The work path which is given in the trajectory frame is also constrained in the workspace of the 3 &ndash / PRS parallel kinematic machine. In the analysis, forward and inverse kinematics solutions are derived as well as the inverse dynamics model using Lagrange&rsquo / s Method. Several algorithms governing the motion of the manipulator are developed. Moreover, optimization goals are defined and evaluated with the genetic algorithm.

In this study, a novel optimal motion planning algorithm is developed for the locomotion of modular robots. The total energy consumption of the robot is considered to be the optimization criteria. In order to determine the energy consumption of the system, the kinematic and dynamic analyses of the system are performed. Due to the variable number of modules in the system, a recursive formulation is developed for both kinematic and dynamic analyses. Coulomb&#039 / s static and dynamic friction models are used to model the frictional forces at the contact points. In modular robot locomotion, the number of contact points and the positions of the contact points vary with time. As a result, the structure of the dynamic equilibrium equations changes. Depending upon the number and type of contacts (i.e., contact with static or dynamic friction), the dynamic equilibrium equations may lead to an overdetermined, regular or underdetermined system of equations. The last case implies that the system is statically indeterminate. A novel solution method, which takes into account the deflections of the flexible links in the modular robot, is introduced to resolve this statical indeterminacy problem. Another important contribution is the identification of the singularities associated with the dynamic equilibrium equations. It is shown that these equations become singular when all tangential contact point velocities are in the same direction. The developed optimal motion planning algorithm ensures that such singularities are avoided. The procedure is illustrated via a modular, self reconfigurable robot called MTRAN. However, the method may be easily extended to other modular robots by changing the structural parameters. In order to display the resulting motion, a visual simulation program is developed for MTRAN using the commercial software Mathematica.

The focus of interest in this study is the RHex robot, which is a hexapod robot that is capable of locomotion over rugged, fractured terrain through statically and dynamically stable gaits while stability of locomotion is preserved. RHex is primarily a research platform that is based on over five years of previous research. The purpose of the study is to build a virtual prototype of RHex robot in order to simulate different behavior without manufacturing expensive prototypes. The virtual prototype is modeled in MSC ADAMS software which is a very useful program to simulate flexible multibody dynamical systems. The flexible half circular legs are modeled in a finite element program (MSC NASTRAN) and are embedded in the main model. Finally a closed loop control mechanism is built in MATLAB to be able to simulate real autonomous RHex robot. The interaction of MATLAB and MSC ADAMS softwares is studied.

Linear springs with variable stiffnesses find some key roles in robotic applications. They are implemented into robotic devices for two main reasons, to increase energy efficiency of walking-running robots and prosthesis, and to get safe human-robot interaction at industrial robots. Being inspired from the human actuation system, a mathematical method to get mechanically adjustable linear springs is noted in the literature / antagonistically working two quadratic springs method. But the proposed solution requires two non-linear springs with quadratic spring characteristics and they are not readily available. Several solutions have been noted in the literature for the acquisition of such non-linear springs. At this thesis work, the solution is realized with a string wrapping around cam mechanism. Two different prototypes were designed and constructed and the second one was physically tested to validate the linear spring behavior. The results displayed good linear spring characteristics with different levels of adjustable spring stiffness. Beside the antagonistically working two quadratic springs method, three novel methods to get mechanically adjustable linear springs are introduced at this thesis. They are based on using hanging weights, an exponential characteristic spring and a linear translation spring respectively. The real prototypes were not manufactured but sample designs using string wrapping around cam mechanisms are made.

The aim of this thesis is to create a flexible multi-purpose modular all terrain robot platform, which has the potential to be used in commercial applications as well as in education and research. In developing this robot platform, it is aimed to use readily available commercial products as much as possible in order to keep the cost of the product low, increase maintainability, and benefit from the improvements made to these components in time. The modularity is attained by designing a two wheeled base module which is autonomous on its own. This base module is composed of two wheels where, the motors located inside these wheels. It is shown that the proposed base module facilitates the configuration of various robots to suit the needs of diverse applications. Detailed design and manufacturing of one of various possible configurations is presented. Performance tests are conducted on this robot configuration and effectiveness of the proposed modular approach is justified.

For an autonomous outdoor mobile robot ability to detect roads existing around is a vital capability. Unstructured roads are among the toughest challenges for a mobile robot both in terms of detection and navigation. Even though mobile robots use various sensors to interact with their environment, being a comparatively low-cost and rich source of information, potential of cameras should be fully utilized. This research aims to systematically investigate the potential use of streaming camera images in detecting unstructured roads. The investigation focused on the use of methods employing Artificial Neural Networks (ANNs). An exhaustive test process is followed where different kernel sizes and feature vectors are varied systematically where trainings are carried out via backpropagation in a feed-forward ANN. The thesis also claims a contribution in the creation of test data where truth images are created almost in realtime by making use of the dexterity of human hands. Various road profiles v ranging from human-made unstructured roads to trails are investigated. Output of ANNs indicating road regions is justified against the vanishing point computed in the scene and a heading vector is computed that is to keep the robot on the road. As a result, it is shown that, even though a robot cannot fully rely on camera images for heading computation as proposed, use of image based heading computation can provide a useful assistance to other sensors present on a mobile robot.

The implant surgery replaces missing tooth to regain functionality and look of the normal tooth after dental operation. Improper placement of implant increases recuperation periods and reduces functionality. The aim of this thesis is to design a passive haptic robotic arm to guide dentist during the implant surgery. In this thesis, the optimum design of the 6R passive haptic robotic arm is achieved. The methodology used in optimization problem involves minimization of end-effector side parasitic forces/torques while maximizing transparency of the haptic device. The transparency of haptic device is defined as realism of forces generated by device in real world compared to forces in virtual world. The multivariable objective function including dynamic equations of 6R robotic arm is derived and the constraints are determined using kinematic equations. The optimization problem is solved using SQP and GA. The link lengths and other relevant parameters along with the location of tool path are optimized. The end-effector parasitic torques/forces are significantly minimized. The results of two optimization techniques have proven to be nearly the same, thus a global optimum solution has been found in the search space. Main contribution of this study is to take spatial nonlinear dynamics into consideration to reduce parasitic torques. Also, a mechanical brake is designed as a passive actuator. The mechanical brake includes a cone based braking system actuated by DC motor. Three different prototypes are manufactured to test performance of the mechanical brake. The final design indicates that the mechanical brake can be used as passive actuators.

In this thesis a custom embedded system and control software developed for an Automated Storage and Retrieval System (AS/RS) which is based on the Computer Integrated Manufacturing Laboratory (CIMLAB) located in the Department of Mechanical Engineering, Middle East Technical University. Primary objective of this study is AS/RSs related control rules can be applicable to the current physical system. The secondary objective is determined as developing the control system in a flexible way that allows adding new equipments to the system and configuring parts of the system. Two types of control board are manufactured and also boards&rsquo / firmware and computer software are developed. These two boards communicate with computer one at a time. Some AS/RS related control rules are implemented at the control software. According to these rules the control software assigns tasks to the related board. Also the control software records necessary information in order to measure the performance of the AS/RS. Several control rules as storage assignment, dwell point and sequencing of storage and retrieval order rules are applicable to the AS/RS without need for low level programming. Because of the physical limitation, batching rules cannot be applied to the current system. Also a graphical user interface is developed for using the system easily and observing the real time status of the system equipments. Two experiments are designed and run in order to show flexibility of the control system. Different control rules applied to each of the experiment. Experiment results put forth the control system was quite successful in meeting the objectives.