A differential steered, 13.6 kg robot was developed as an intelligent tire testing system and was used to investigate the potential of using piezoelectric film sensors in small tube-type pneumatic tires to characterize tire-ground interaction.<br />One focus of recent research in the tire industry has been on instrumenting tires with sensors to monitor the tire, vehicle, or external environment. On small robots, tire sensors that measure the forces and deflections in the contact patch could be used to improve energy efficiency and/or mobility during a mission.<br />The robot was assembled from a SuperDroid Robots kit and instrumented with low-cost piezoelectric film sensors from Measurement Specialties between the inner tube and the tire.  An unlaminated and a laminated sensor were placed circumferentially along the tread and an unlaminated sensor was placed along the sidewall.  A slip ring transferred the signals from the tire to the robot. There, the signal conditioning circuit extended the time constant of the sensors and filtered electromagnetic interference.  The robot was tested with a controlled power sequence carried out on polished cement, ice, and sand at three power levels, two payload levels, and with two tire sizes.<br />The results suggest that the sensors were capable of detecting normal pressure, deflection, and/or longitudinal strain.  Added payload increased the amplitude of the signals for all sensors.  On the smaller tires, sensors generally recorded a smaller, wider signal on sand compared to cement, indicating the potential to detect contact patch pressure and length.  The signals recorded by the unlaminated sensor along the tread of the smaller tire were lower on ice compared to cement, indicating possible sensitivity to tractive force.  Results were less consistent for the larger tires, possibly due to the large tread pattern. / Master of Science

For their inherent stability and simple dynamics of motion, wheeled robots are very common in robotics applications. Many highly complex robots are being developed in research laboratories, but wheeled robots remain the most used robot in real-world situations. One of the most significant downfalls of wheeled robots is their inability to navigate over large obstacles or steps without assistance. A wheeled robot is capable of climbing steps that are no larger than the radius of the robot's tires, but steps larger than this are impassable by simply rolling over the object. Active systems that have been designed for use on wheeled robots to lift the robot over a step are effective, but are generally not easily implemented on a range of robotic platforms. Also, the additional size, cost, and power required for the additional actuators is a major drawback to these options. A solution to these problems is a novel, passive dynamic system that is inertially excited by the motion of the robot to allow the robot to rotate on each axle and "hop" over the step. The system that was investigated for this project is a sliding mass-spring that shifts forward and backward based on the acceleration of the base robot. With high acceleration, the mass is pushed towards the rear wheel from an inertial force and compresses a spring that creates a moment on the body to induce rotation. This torque can cause the robot to "pop a wheelie", lifting its front wheels off the ground. To pull the rear wheels up, the inertial force from a large deceleration of the robot shifts the mass forward and extends a spring. These effects result in a moment acting in the opposite direction that can rotate the robot on its front axle and pull the rear wheels up. By coordinating the acceleration and deceleration of the robot, the front wheels can lift over a step and the rear wheels can be pulled up afterward — both actions being a product of inertial actuation. This passive system does not need additional actuators or direct control of the sliding mass, so it can be more durable over a robot's lifetime. Other advantages of this system are that the design is simple, cost-effective, and can be adjusted and retrofit to a different wheeled robot in the future with little effort. By deriving the equations of motion of this inertially actuated sliding mass, the dynamics show how design parameters of the system can be tuned to better optimize the overall step-climbing process. A computer simulation was created to visualize the robotic step-climbing process and demonstrate the effects of changing design parameters. An implementation of this sliding mass system was added to a wheeled robot, and the results from experiments were compared to simulated trials. This research has shown that an inertially actuated sliding mass can effectively enable a wheeled robot to climb a step that was previously impassable and that the system can be tuned for other wheeled robots using an understanding of the system dynamics. / Master of Science

This thesis addresses the problem of wireless transmission between the operator station and the robot. There is a solution presented by way of testing the parameters of wireless modules, compare them in the environment and the draft protocol.

This thesis addresses the problem of wireless transmission between the operator station and the robot. There is a solution presented by way of testing the parameters of wireless modules, compare them in the environment and the draft protocol.

The main subject of this thesis is use of inertial sensors for better motion and stability control of mobile robots. In background research are described the basic methods of mobile robots localization. Second part of background research is about mobile robot stability, in this part are described the methods of mobile robots stability control. In next part is description of MEMS accelerometers and gyroscopes and description of basic method of filtering and integration which are useful for input processing of these sensors. Thesis continues with inertial sensors analysis for application on control of wheeled and legged mobile robots. In end of thesis are specified the experiment results, which confirm the applicability of sensors for mobile robot control.

The objective of this thesis is to analyze the kinematics of a mobile parallel robot with contribution that pertain to the singularity analysis, the optimization of geometric parameters and the optimal control to avoid singularities when navigating across singular geometric configurations. The analysis of the workspace and singularities is performed in a prescribed reference workspace regions using discretization method. Serial and parallel singularities are analytically analyzed and all possible singular configurations are presented. Kinematic conditioning index is used to determine the robot’s proximity to a singular configuration. A method for the determination of a continuous and singularity-free workspace is detailed. The geometric parameters of the system are optimized in various types of pipe-like structures with respect to a suitable singularity index, in order to avoid singularities during the navigation across elbows. The optimization problem is formulated with an objective to maximize the reachable workspace and minimize the singularities. The objective function is also subjected to constraints such as collision avoidance, singularity avoidance, workspace continuity and contact constraints imposed between the boundaries and the wheels of the robot. A parametric variation method is used as a technique to optimize the design parameters. The optimal design parameters found are normalized with respect to the width of the pipe-like structures and therefore the results are generalized to be used in the development phase of the robot. An optimal control to generate singularity-free trajectories when the robotic device has to cross a geometric singularity in a sharp 90◦ elbow is proposed. Such geometric singularity inherently leads to singularities in the Jacobian of the system, and therefore a modified device with augmented number of degrees of freedom is introduced to be able to generate non-singular trajectories.

The objective of this thesis is to analyze the kinematics of a mobile parallel robot with contribution that pertain to the singularity analysis, the optimization of geometric parameters and the optimal control to avoid singularities when navigating across singular geometric configurations. The analysis of the workspace and singularities is performed in a prescribed reference workspace regions using discretization method. Serial and parallel singularities are analytically analyzed and all possible singular configurations are presented. Kinematic conditioning index is used to determine the robot’s proximity to a singular configuration. A method for the determination of a continuous and singularity-free workspace is detailed. The geometric parameters of the system are optimized in various types of pipe-like structures with respect to a suitable singularity index, in order to avoid singularities during the navigation across elbows. The optimization problem is formulated with an objective to maximize the reachable workspace and minimize the singularities. The objective function is also subjected to constraints such as collision avoidance, singularity avoidance, workspace continuity and contact constraints imposed between the boundaries and the wheels of the robot. A parametric variation method is used as a technique to optimize the design parameters. The optimal design parameters found are normalized with respect to the width of the pipe-like structures and therefore the results are generalized to be used in the development phase of the robot. An optimal control to generate singularity-free trajectories when the robotic device has to cross a geometric singularity in a sharp 90◦ elbow is proposed. Such geometric singularity inherently leads to singularities in the Jacobian of the system, and therefore a modified device with augmented number of degrees of freedom is introduced to be able to generate non-singular trajectories.

This thesis describes development of control algorithm for a wheelchair. Wheelchair should be capable of tracking and following a wall or a similar flat surface. Thesis is supposed to be an extension of the previous concept, whose purpose was to allow remote telepresence control of this wheelchair. SRF08 ultrasonic range finders are used to measure distance from the wall. Furthermore, image processing for mark detection is discussed. Purpose of these marks is to increase precision during final phase of the parking.