Robust balancing and position control of a single spherical wheeled mobile platform

Self-balancing mobile platforms with single spherical wheel, generally called ballbots, are suitable example of underactuated systems. Balancing control of a ballbot platform, which aims to maintain the upright orientation by rejecting external disturbances, is important during station keeping or trajectory tracking. In this paper, acceleration based balancing and position control of a single spherical wheeled mobile platform that has three single-row omniwheel drive mechanism is examined. Robustness of the balancing controller is achieved by employing cascaded position, velocity and current control loops enhanced with acceleration feedback (AFB) to provide higher stiffness to the platform. The effectiveness of the proposed balancing controller is compared with commonly used optimal state feedback method. Additionally, the position controller is designed by utilizing the dynamic conversion of desired torques on the ball that are calculated from virtual control inputs generated in the inertial coordinates. Dynamical model of a ballbot platform is investigated by considering highly nonlinear couplings. Performance of the controllers are presented via simulation results where the external torques were applied on the body in order to test disturbance rejection capabilities

Control and implementation of a single wheel holonomic vehicle

This paper proposes a robot balanced on a ball. In contrast to an inverted pendulum with two wheels, such as the Segway. The robot proposed in this paper is equipped with three omnidirectional wheels with DC motors that drive the ball and two sets of rate gyroscopes and accelerometers as measurement sensors. The robot has a simple design. Inverted pendulum control is applied in two axes for stabilization, and commanded motions are converted into velocity commands for the three wheels. The mechanism, control method, and experimental results described in this paper.Magíster en Ingeniería ElectrónicaMaestrí

Control and implementation of a single wheel holonomic vehicle

This paper proposes a robot balanced on a ball. In contrast to an inverted pendulum with two wheels, such as the Segway. The robot proposed in this paper is equipped with three omnidirectional wheels with DC motors that drive the ball and two sets of rate gyroscopes and accelerometers as measurement sensors. The robot has a simple design. Inverted pendulum control is applied in two axes for stabilization, and commanded motions are converted into velocity commands for the three wheels. The mechanism, control method, and experimental results described in this paper.Magíster en Ingeniería ElectrónicaMaestrí

Dynamic Modeling and Control of Spherical Robots

In this work, a rigorous framework is developed for the modeling and control of spherical robotic vehicles. Motivation for this work stems from the development of Moball, which is a self-propelled sensor platform that harvests kinetic energy from local wind fields. To study Moball's dynamics, the processes of Lagrangian reduction and reconstruction are extended to robotic systems with symmetry-breaking potential energies, in order to simplify the resulting dynamic equations and expose mathematical structures that play an important role in subsequent control-theoretic tasks. These results apply to robotic systems beyond spherical robots. A formulaic procedure is introduced to derive the reduced equations of motion of most spherical robots from inspection of the Lagrangian. This adaptable procedure is applied to a diverse set of robotic systems, including multirotor aerial vehicles. Small time local controllability (STLC) results are derived for barycentric spherical robots (BSR), which are spherical vehicles whose locomotion depends on actuating the vehicle's center of mass (COM) location. STLC theorems are introduced for an arbitrary BSR on flat, sloped, or smooth terrain. I show that STLC depends on the surjectivity of a simple steering matrix. An STLC theorem is also derived for a class of commonly encountered multirotor vehicles. Feedback linearizing and PID controllers are proposed to stabilize an arbitrary spherical robot to a desired trajectory over smooth terrain, and direct collocation is used to develop a feedforward controller for Moball specifically. Moball's COM is manipulated by a novel system of magnets and solenoids, which are actuated by a "ballistic-impulse" controller that is also presented. Lastly, a motion planner is developed for energy-harvesting vehicles. This planner charts a path over smooth terrain while balancing the desire to achieve scientific objectives, avoid hazards, and the imperative of exposing the vehicle to environmental sources of energy such as local wind fields and topology. Moball's design details and experimental results establishing Moball's energy-harvesting performance (7W while rolling at a speed of 2 m/s), are contained in an Appendix.</p

Kinematics and analysis of driven sphere by rollers

九州工業大学博士学位論文 学位記番号：生工博甲第376号 学位授与年月日：令和2年3月25日第１章 序論|第２章 ローラ駆動される球体の運動学|第３章 球体運動学の検証|第４章 ロボカップへの適用|第５章 結論及び展望九州工業大学令和元年

Cellulo: Tangible Haptic Swarm Robots for Learning

Robots are steadily becoming one of the significant 21st century learning technologies that aim to improve education within both formal and informal environments. Such robots, called Robots for Learning, have so far been utilized as constructionist tools or social agents that aided learning from distinct perspectives. This thesis presents a novel approach to Robots for Learning that aims to explore new added values by means of investigating uses for robots in educational scenarios beyond those that are commonly tackled: We develop a platform from scratch to be "as versatile as pen and paper", namely as composed of easy to use objects that feel like they belong in the learning ecosystem while being seamlessly usable across many activities that help teach a variety of subjects. Following this analogy, we design our platform as many low-cost, palm-sized tangible robots that operate on printed paper sheets, controlled by readily available mobile computers such as smartphones or tablets. From the learners' perspective, our robots are thus physical and manipulable points of hands-on interaction with learning activities where they play the role of both abstract and concrete objects that are otherwise not easily represented. We realize our novel platform in four incremental phases, each of which consists of a development stage and multiple subsequent validation stages. First, we develop accurately positioned tangibles, characterize their localization performance and test the learners' interaction with our tangibles in a playful activity. Second, we integrate mobility into our tangibles and make them full-blown robots, characterize their locomotion performance and test the emerging notion of moving vs. being moved in a learning activity. Third, we enable haptic feedback capability on our robots, measure their range of usability and test them within a complete lesson that highlights this newly developed affordance. Fourth, we develop the means of building swarms with our haptic-enabled tangible robots and test the final form of our platform in a lesson co-designed with a teacher. Our effort thus contains the participation of more than 370 child learners over the span of these phases, which leads to the initial insights into this novel Robots for Learning avenue. Besides its main contributions to education, this thesis further contributes to a range of research fields related to our technological developments, such as positioning systems, robotic mechanism design, haptic interfaces and swarm robotics