Development of wireless control system for a spherical robot

The purpose of this thesis was to develop a control method which can reduce oscillation of lateral motion for a pendulum driven spherical robot operating on flat surface. The spherical robot provides a unique mobility and has several applications in surveillance and entertainment. Controlling a spherical robot is a challenging problem till today due to its nature of kinematics and dynamics. Firstly, its nonholonomic nature prohibits the use of conventional state feedback control laws. Secondly, kinematics of a spherical robot cannot be expressed as a chained-form system to utilize nonholonomic control algorithms. However, various types of nonlinear control algorithms were proposed to settle the problem though none of them provided satisfactory result. The kinematics and dynamics of the pendulum driven spherical robot was investigated followed by linearization for longitudinal and lateral motions through frequency and state space transformation. Moreover, the controllability of the states of the system was maintained during linearization. A robust self-tuning sliding mode con troller which suspends oscillation, maintains desired speed and compensates for unmodeled parameters was developed. The implemented control system consists of control station, prototype robot equipped with on-board microcontroller and sensors, and wireless communication link. Simulation and experimentation were conducted to test peformance of the control laws in suppressing oscillation and maintaining desired speed of the robot. The robot traveled to the commanded trajectory containing straight line and curve with relatively minimum oscillation at desired speed. Thus, the sliding mode control is an effective controller

Design, construction and control of a spherical rolling robot with internal two-wheel cart

This elaboration presents a spherical rolling robot with a 2-wheel cart. The custom design of the hardware and control software is presented to demonstrate the solution. The robot was started to realize an autonomous task. The embedded robot control system is based on a 32-bit microcontroller and uses a Bluetooth module for wireless communication. The simplified model has been proposed and its parameters identified. The results obtained at the simulation and experimental stages are shown and compared. Finally, the robot’s motion was recorded and analyzed with the support of image signal processing techniques.W artykule przedstawiony został opis sferycznego robota mobilnego z napędem w postaci dwukołowego wózka. Praca prezentuje dedykowany układ mechaniczny, elektroniczny oraz oprogramowanie sterujące. System wbudowany robota jest oparty na 32-bitowym mikrokontrolerze oraz wykorzystuje bezprzewodową komunikację Bluetooth. Parametry uproszczonego modelu matematycznego robota sferycznego zostały zidentyfikowane, a wyniki symulacji porównano do rezultatów rzeczywistych eksperymentów. Analiza obrazu zarejestrowanego za pomocą zewnętrznej kamery pozwoliła na obserwacje trajektorii ruchu robota

Control of a Spherical Robot Rolling Over Irregular Surfaces

Pendulum-Driven Spherical Robots are a type of spherical robot whose motion is achieved by controlling two motors for longitudinal and lateral motion. This configuration makes the robot a non-holonomic system, which impedes it from navigating directly towards a target. In addition, controlling its motion on inclined irregular surfaces is also an issue that has not received much attention. In this work, we addressed these two issues by proposing a methodology to control both motors using PID controllers. However, we propose tuning the controller’s gains using stochastic signals for the longitudinal controller because by varying the motor’s torque, the robot is more susceptible to destabilization in combination with a classical gain tuning methodology for the second controller. Our results indicate that this enables the robot to perform motion on inclined irregular surfaces. We also propose using semicircular trajectories to plan the robot’s motion to reach a target successfully even when moving on inclined irregular surfaces. We have carried out experiments in the Webots simulator, showing that our approach does not overshoot while reaching a settling time of almost 0. These results outperform the Ziegler-Nichols PID controller

Design and control of a spherical VTOL vehicle

This research presents the design of a spherically shaped Unmanned Aircraft System (UAS) called the All-Terrain Land and Air Sphere (ATLAS). ATLAS is designed to include competing design requirements necessary for operating in an indoor cluttered environment for emergency response and inspection applications, particularly around people, including the ability to hover, execute coordinated maneuvers with translational flight, land on uneven terrain, and return to flight. The spherical frame can interact with the environment and land without the need for coordinated vertical landing maneuverability such as other rotary winged devices, including multi-rotors or helicopters. One of the features that sets ATLAS apart from other similarly sized drones is the capability to roll on the ground to maneuver to a new location and avoid obstacles before executing an upright maneuver for recovery to flight. These features make ATLAS suitable as a search and rescue platform in supporting both aerial and ground operations. The diameter and payload capability of the ATLAS is scalable depending on the mission requirements. While multiple sizes have been developed, the primary system presented herein has a diameter of 40 cm (16 inch) and weighs about 900 grams (2 lbs).The first part of this study investigates the characteristic of a passive flight control mechanism made up of eight movable hinged arc vanes positioned radially around the propeller tips. Such passive devices are not presented in any open propeller platform. Each vane is hinged and mechanically restricted to rotate between 0 to 90 degrees. A series of bench testing results show that these passive control surfaces generate an upward or downward force depending on the proximity and strength of the airflow interaction coming toward the propeller during flight conditions. These passive vanes can also help stabilize the vehicle in contrast to an open propeller setup.The second part of this study evaluates control schemes for a single propeller with multiple control surfaces. Unlike ducted fans and multi-rotor platforms, the control vanes are strongly coupled to provide stability and control along all principal axes while counteracting the induced torque effects generated by a single pitch propeller. ATLAS has demonstrated stable flight tests by using a Proportional-Integrator-Derivative (PID) control based on the proposed control scheme and can successfully perform flight recovery from in-flight disturbances through the implementation of a non-linear model using the Newton-Euler formulation. Ground maneuvers are made possible by reversing the propeller direction to provide sufficient reverse thrust without the need for a variable pitch propeller

Controller Design Of Unicycle Mobile Robot

ABSTRACT: The ability of unicycle mobile robot to stand and move around using one wheel has attracted a lot of researchers to conduct studies about the system, particularly in the design of the system mechanisms and the control strategies. This paper reports the investigation done on the design of the controller of the unicycle mobile robot system to maintain its stability in both longitudinal and lateral directions. The controller proposed is a Linear Quadratic Controller (LQR) type which is based on the linearized model of the system. A thorough simulation studies have been carried out to find out the performance of the LQR controller. The best controller gain, K acquired through the simulation is selected to be implemented and tested in the experimental hardware. Finally, the results obtained from the experimental study are compared to the simulation results to study the controller efficacy. The analysis reveals that the proposed controller design is able to stabilize the unicycle mobile robot. ABSTRAK: Kemampuan robot satu roda untuk berdiri dan bergerak di sekitar telah menarik minat ramai penyelidik untuk mengkaji sistem robot terutamanya didalam bidang rangka mekanikal dan strategi kawalan robot. Kertas kajian ini melaporkan hasil penyelidikan ke atas strategi kawalan robot bagi memastikan sistem robot satu roda dapat distabilkan dari arah sisi dan hadapan. Strategi kawalan yang dicadang, menggunakan teknik kawalan kuadratik sejajar (Linear Quadratic Control) yang berdasarkan model robot yang telah dipermudahkan. Kajian simulasi secara terperinci telah dijalankan bagi mengkaji prestasi strategi kawalan yang dicadangkan. Dari kajian simulasi sistem robot, pemilihan faktor konstan, K yang sesuai di dalam strategi kawalan telah dibuat, agar dapat dilaksanakan ke atas sistem robot yang dibangunkan. Keputusan dari kajian simulasi dan tindak balas oleh sistem robot yang dibangunkan akhirnya dibandingkan bagi melihat kesesuaian faktor kostan, K yang dipilih. Analisa menunjukkan dengan menggunakan strategi kawalan yang dicadangkan dapat menstabilkan robot satu roda. KEYWORDS: unicycle mobile robot; nonholonomic system; LQ

Shared control for navigation and balance of a dynamically stable robot.

by Law Kwok Ho Cedric.Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.Includes bibliographical references (leaves 106-112).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.2 --- Related work --- p.4Chapter 1.3 --- Thesis overview --- p.5Chapter 2 --- Single wheel robot: Gyrover --- p.9Chapter 2.1 --- Background --- p.9Chapter 2.2 --- Robot concept --- p.11Chapter 2.3 --- System description --- p.14Chapter 2.4 --- Flywheel characteristics --- p.16Chapter 2.5 --- Control patterns --- p.20Chapter 3 --- Learning Control --- p.22Chapter 3.1 --- Motivation --- p.22Chapter 3.2 --- Cascade Neural Network with Kalman filtering --- p.24Chapter 3.3 --- Learning architecture --- p.27Chapter 3.4 --- Input space --- p.29Chapter 3.5 --- Model evaluation --- p.30Chapter 3.6 --- Training procedures --- p.35Chapter 4 --- Control Architecture --- p.38Chapter 4.1 --- Behavior-based approach --- p.38Chapter 4.1.1 --- Concept and applications --- p.39Chapter 4.1.2 --- Levels of competence --- p.44Chapter 4.2 --- Behavior-based control of Gyrover: architecture --- p.45Chapter 4.3 --- Behavior-based control of Gyrover: case studies --- p.50Chapter 4.3.1 --- Vertical balancing --- p.51Chapter 4.3.2 --- Tiltup motion --- p.52Chapter 4.4 --- Discussions --- p.53Chapter 5 --- Implement ation of Learning Control --- p.57Chapter 5.1 --- Validation --- p.57Chapter 5.1.1 --- Vertical balancing --- p.58Chapter 5.1.2 --- Tilt-up motion --- p.62Chapter 5.1.3 --- Discussions --- p.62Chapter 5.2 --- Implementation --- p.65Chapter 5.2.1 --- Vertical balanced motion --- p.65Chapter 5.2.2 --- Tilt-up motion --- p.68Chapter 5.3 --- Combined motion --- p.70Chapter 5.4 --- Discussions --- p.72Chapter 6 --- Shared Control --- p.74Chapter 6.1 --- Concept --- p.74Chapter 6.2 --- Schemes --- p.78Chapter 6.2.1 --- Switch mode --- p.79Chapter 6.2.2 --- Distributed mode --- p.79Chapter 6.2.3 --- Combined mode --- p.80Chapter 6.3 --- Shared control of Gyrover --- p.81Chapter 6.4 --- How to share --- p.83Chapter 6.5 --- Experimental study --- p.88Chapter 6.5.1 --- Heading control --- p.89Chapter 6.5.2 --- Straight path --- p.90Chapter 6.5.3 --- Circular path --- p.91Chapter 6.5.4 --- Point-to-point navigation --- p.94Chapter 6.6 --- Discussions --- p.95Chapter 7 --- Conclusion --- p.103Chapter 7.1 --- Contributions --- p.103Chapter 7.2 --- Future work --- p.10

Underwater Remotely Operated Vehicle featuring advances in rotational actuation, communication, and localization

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 101-103).The design for a spherical Remotely Operated Vehicle (ROV) with a camera, called the Eyeball ROV due to motions similar to the human eye, is presented in this thesis. The ROV features an actuation scheme that utilizes a two-axis gimbal for changing the location of the center of mass of the ROV. This creates continuous and unlimited rotations in place on the part of the ROV, allowing the camera to be panned and tilted. A model of the ROV is presented, and control was tested in both simulation and experiments. In addition, a dual-use system for both communication and localization of the ROV is presented. This novel dual-use system uses visible blue light (-470nm) to relay data in addition to providing a beacon with which the orientation and position in space of the ROV was estimated. This localization algorithm was implemented using an Extended Kalman Filter (EKF), and was tested in both simulations and experiments.by Ian Charles Rust.S.M

Balance-bot

Research on inverted pendulum has gained momentum over the last decade on a number of robotic laboratories over the world; due to its unstable proprieties is a good example for control engineers to verify a control theory. To verify that the pendulum can balance we can make some simulations using a closed-loop controller method such as the linear quadratic regulator or the proportional–integral–derivative method. Also the idea of robotic teleoperation is gaining ground. Controlling a robot at a distance and doing that precisely. However, designing the tool to takes the best benefit of the human skills while keeping the error minimal is interesting, and due to the fact that the inverted pendulum is an unstable system it makes a compelling test case for exploring dynamic teleoperation. Therefore this thesis focuses on the construction of a two-wheel inverted pendulum robot, which sensor we can use to do that, how they must be integrated in the system and how we can use a human to control an inverted pendulum. The inverted pendulum robot developed employs technology like sensors, actuators and controllers. This Master thesis starts by presenting an introduction to inverted pendulums and some information about related areas such as control theory. It continues by describing related work in this area. Then we describe the mathematical model of a two-wheel inverted pendulum and a simulation made in Matlab. We also focus in the construction of this type of robot and its working theory. Because this is a mobile robot we address the theme of the teleoperation and finally this thesis finishes with a general conclusion and ideas of future work.Orientador: Ian Oakle