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In this paper a novel formation control frame-work is presented for unmanned autonomous ground vehicles based on analytical mechanics and multibody interpretation. The coordinated motion is achieved by introducing holonomic constraint functions that describe the interaction between the vehicles. These functions are interpreted as constraint forces and the decentralized control law is determined for...
In this paper an improved approach is presented for the state estimation of unmanned aerial vehicles (UAVs). The three-loop technique is based on Extended Kalman Filters. From them EKF1 solve the quaternion based orientation (attitude) estimation using IMU and magnetometer. EKF2 improves the attitude estimation if GPS information is present. The third filter EKF3 determines the remaining state variables...
In this paper a hierarchically structured framework is proposed for the time-optimal trajectory planning and control of autonomous electric vehicles with state and input constraints for fixed test paths. The time-optimal reference signals are obtained by solving a dynamic nonlinear optimal control problem associated with the kinematic model of the vehicle using direct discretization and multiple shooting...
In this paper an adaptive control law is designed for formation control of underactuated autonomous ground vehicles based on the leader-follower approach and kinematics equations. The follower vehicles have limited knowledge about the leader's states. The unknown term containing the velocity information of the leader is estimated using neural networks with online adaptive weight tuning laws. The decentralized...
This paper proposes a novel method for the high speed tracking control of unmanned ground vehicles (UGVs) subject to load changes. The vehicle is modeled as a 16 degree-of-freedom multi-body system whose dynamics is derived using robotic formalism. The hierarchical control structure comprises two levels: a high-level (HLC) and a low-level (LLC) control system. The states are estimated with a two-stage...
In this paper a novel method is presented for hierarchical control of autonomous vehicles consisting of high-level (HLC) and low-level (LLC) control systems. The LLC system can be commanded to assure a prescribed velocity and steering profile using PID-type active suspension, velocity and steering control. The outputs of the LLC system are the generalized forces and moments required by the vehicle...
Chapter 6 focuses on the predictive control of airplanes and the backstepping control of quadrotor helicopters. The airplane is an LPV system which is internally stabilized by disturbance observer and externally controlled by high level RHC. The control design is illustrated for the pitch rate control of an aircraft. The internal system is linearized at the beginning of every horizon and RHC is applied...
The final chapter summarizes the introduced modeling and control techniques which were presented in this book. The need of development of such control algorithms which take into consideration the smooth and nonsmooth nonlinearities that appear in the model of robotic systems and vehicles was a motivating factor of this work. Such algorithms were presented that are theoretically founded and at the...
Chapter 1 introduces some general definitions for autonomous vehicles and robots and it also gives a short historical review of the most important steps of robot and vehicle control development. The motivation of the research work summarized in this book is also presented here. The final part shortly outlines the structure of the book.
Chapter 10 introduces a hybrid model for mechanical control systems with Stribeck friction and backlash, using which the stability of these systems can be analyzed. The model is applied for state feedback controller design. Two types of limit cycles, that can appear in these control systems due to wrong controller parameterization, are analyzed in the second part of the chapter, limit cycles around...
Chapter 2 focuses on the basic nonlinear control methods. First, the main classes of nonlinear systems are summarized, then some examples are presented how to find the dynamic model of simple systems and an overview of the stability methods is given. It is followed by an introduction to the concepts of some often used nonlinear control methods like input/output linearization, flatness control, backstepping...
The first part of the Chap. 9 presents the basic theoretical notions from the field of modeling and stability of nonsmooth systems. Afterward, it focuses on modeling of two nonsmooth nonlinearities that can influence the performances of mechanical control systems: friction and backlash. The most important static and dynamic friction models, that are applied in friction compensation algorithms, are...
Chapter 3 focuses on the dynamic modeling of the robots and vehicles in unified approach. First, the kinematic and dynamic model of the rigid body is discussed which is the basis for the further investigations. For robots, the dynamic model is developed using Appell’s equation and Lagrange’s equation. For ground cars, a nonlinear dynamic model, two nonlinear input affine approximations and a linearized...
Chapter 7 focuses on the dominant control methods of ships. First, the typical structure of the control system is shown. A short overview is given about the path design methods including Line-of-Sight guidance and wave filtering. The state estimation using GPS and IMU is discussed and observers are suggested to solve the problem. From the wide spread control methods the acceleration feedback with...
Chapter 8 focuses on the formation control of unmanned ground and marine vehicles moving in horizontal plane. For stabilization of ground vehicles in formation, the potential field method is applied. The controller consists of three levels, the low level linearizing controller, the high level formation controller and the medium level stabilizing controller. The chosen potential function is structured...
Chapter 4 focuses on the most important control methods of industrial robots. From the control methods not using the dynamic model of the robot, first the decentralized three-loop cascade control is presented. This classical approach tries to apply linear control methods but its precision and allowable speed is limited. Then advanced control methods follow based on the robot dynamic model for high...
Chapter 5 focuses on the high level nonlinear control methods for cars (ground vehicles). The main tasks are path design, control algorithm development and control realization. These steps are demonstrated in the frame of the development of a collision avoidance system (CAS). From the large set of path design methods, the principle of elastic band is chosen. The car can be modeled by full (non-affine)...
Chapter 11 deals with the identification of nonsmooth mechanical nonlinearities and tracking control of mechatronic systems in the presence of friction. First, a friction and backlash measurement and identification method is presented for robotic manipulators that can be performed in closed loop using velocity controller. It is shown, how the procedure can be extended for hydraulic actuators. Second,...
Tracking of autonomous vehicles and the high-precision positioning of robotic manipulators require advanced modeling techniques and control algorithms. Controller design should take into account any model nonlinearities. Nonlinear Control of Vehicles and Robots develops a unified approach to the dynamic modeling of robots in terrestrial, aerial and marine environments. To begin with, the main classes...
In this paper a novel method was presented for the multi-body modeling of double-track ground vehicles based on Appell formalism. Kinematic constraints were introduced in form of Lagrange-multipliers that assure zero vertical accelerations at the wheel/ground contact points. A fictitious control system was used to find some non-available parts of the reference signals. Based on the constrained dynamic...
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