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

Computational dynamics: theory and applications of multibody systems

International audienceMultibody system dynamics is an essential part of computational dynamics a topic more generally dealing with kinematics and dynamics of rigid and flexible systems, finite elements methods, and numerical methods for synthesis, optimization and control including nonlinear dynamics approaches. The theoretical background of multibody dynamics is presented, the efficiency of recursive algorithms is shown, methods for dynamical analysis are summarized, and applications to vehicle dynamics and biomechanics are reported. In particular, the wear of railway wheels of high-speed trains and the metabolical cost of human locomotion is analyzed using multibody system methods

Sliding mode control trajectory tracking implementation on underactuated dynamic systems

Master of ScienceDepartment of Mechanical EngineeringWarren N. WhiteThe subject of linear control is a mature subject that has many proven powerful techniques. Recent research generally falls into the area of non-linear control. A subsection of non-linear control that has garnered a lot of research recently has been in underactuated dynamic systems. Many applications of the subject exist in robotics, aerospace, marine, constrained systems, walking systems, and non-holonomic systems. This thesis proposes a sliding mode control law for the tracking control of an underactuated dynamic system. A candidate Lyapunov function is used to build the desired tracking control. The proposed control method does not require the integration of feedback as does its predecessor. The proposed control can work on a variety of underactuated systems. Its predecessor only worked on those dynamic systems that are simply underactuated (torques acting on some joints, no torques acting on others). For dynamic systems that contain a roll without slip constraint, often a desired trajectory to follow is related to dynamic coordinates through a non-holonomic constraint. A navigational control is shown to work in conjunction with the sliding mode control to allow tracking of these desired trajectories. The methodology is applied through simulations to a holonomic case of the Segbot, an inverted cart-pole, a non-holonomic case of Segbot, and a rolling wheel. The methodology is implemented on an actual Segbot and shown to provide more favorable tracking results than linear feedback gains

Vibration, Control and Stability of Dynamical Systems

From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”

Advanced Strategies for Robot Manipulators

Amongst the robotic systems, robot manipulators have proven themselves to be of increasing importance and are widely adopted to substitute for human in repetitive and/or hazardous tasks. Modern manipulators are designed complicatedly and need to do more precise, crucial and critical tasks. So, the simple traditional control methods cannot be efficient, and advanced control strategies with considering special constraints are needed to establish. In spite of the fact that groundbreaking researches have been carried out in this realm until now, there are still many novel aspects which have to be explored

Rest-to-Rest Trajectory Planning for Underactuated Cable-Driven Parallel Robots

This article studies the trajectory planning for underactuated cable-driven parallel robots (CDPRs) in the case of rest-to-rest motions, when both the motion time and the path geometry are prescribed. For underactuated manipulators, it is possible to prescribe a control law only for a subset of the generalized coordinates of the system. However, if an arbitrary trajectory is prescribed for a suitable subset of these coordinates, the constraint deficiency on the end-effector leads to the impossibility of bringing the system at rest in a prescribed time. In addition, the behavior of the system may not be stable, that is, unbounded oscillatory motions of the end-effector may arise. In this article, we propose a novel trajectory-planning technique that allows the end effector to track a constrained geometric path in a specified time, and allows it to transition between stable static poses. The design of such a motion is based on the solution of a boundary value problem, aimed at a finding solution to the differential equations of motion with constraints on position and velocity at start and end times. To prove the effectiveness of such a method, the trajectory planning of a six-degrees-of-freedom spatial CDPR suspended by three cables is investigated. Trajectories of a reference point on the moving platform are designed so as to ensure that the assigned path is tracked accurately, and the system is brought to a static condition in a prescribed time. Experimental validation is presented and discussed