Search

The paper proposes the analytical design method of the control system for movement of a mobile robot with external, not measured disturbances. To exclude the influence of these disturbances on error of the control system the digital selectively-invariant control system is offered to use. The control on output and impacts and the Kulebakin's images of the disturbances are used for solution of the design problem of the selectively-invariant control system. The offered approach can be used for the rejection of the influence of different external disturbances on control systems.

in this report a method of trajectory planning for a mobile robot with maneuver restrictions is developed. The maneuver restrictions depends on robot's velocity. Restrictions are represented by virtual obstacles that close up the inaccessible to the robot sectors when it moves at specific velocity. The proposed method is compatible with any path-planning algorithm. The paper describes trajectory planning system of mobile robot based on rapidly exploring random trees method. Dijkstra's algorithm searches the shortest path in the tree. Motion control system calculates the desired yaw angle and velocity of the robot and automatically reduces the velocity when approaching obstacles and while turning. Simulation results for the wheeled robot in obstructed environment are presented.

The algorithm of the digital adaptive controller is offered in this article for control systems with identification of uncertain multivariable continuous-time objects. The adaptive controller includes unit of digital identification and unit of digital control. The algorithm of the identification unit allows to define the transfer matrix of the uncertain continuous-time plant. Unlike traditional methods of identification, the offered analytical algorithm uses Markov parameters not of the uncertain continuous-time plant, but virtual discrete-like plant. Markov parameters are determined by data of I/O of the uncertain continuous-time plant. The algorithm of the control unit is developed with use of control of two types: decomposition control and digital control on the output and impacts. The order and parameters of the control unit are determined by the method of the analytical design of digital control systems. Normalized standard transfer functions are used to create the transfer functions of the adaptive system according to required values of astatism order, settling time and overshot. The effectiveness of the proposed algorithm of adaptive controller is illustrated by a numerical example. The proposed approach can be applied to create control systems for agricultural, food, mining, and other industries.

This article discusses methods for detecting UAVs in the radio frequency range. The analysis of the existing UAV detection systems is carried out. An overview of ways to counter UAVs is presented, in particular, by carrying out attacks on navigation and communication systems. A prototype of the UAV detection system, which is based on the UAV, is presented. The UAV detection function has been implemented based on the analysis of the radio frequency spectrum.

The article presents multi-contour position vehicle control system ensuring astaticism and adaptive tuning of parameters. Positioning of the controlled object in a pre-defined point is considered. In the first contour the control action is calculated to provide the desired dynamics of the closed-loop system with astaticism of the second order. The second control contour performs tuning of the parameters according to the known algorithms of searchless adaptation using the reference models. An algorithm is proposed resulting in pre-set values of the characteristic equation of the tuned system. The first and the second contours of the control system compensate the external disturbances and adapt to parametric disturbances. The third contour performs tuning of the reference model that makes it possible to change the requirements to the closed-loop system depending on whether the system satisfies the limitations on control actions. When the limitations on the amplitude of control actions are reached, the system increases the time constants of the reference control. Stability of the closed-loop system was analyzed using the Lyapunov functions method. The proposed control algorithms are demonstrated using an example of a vehicle described by equations of solid body kinematics and dynamics. In the equations of dynamics the resisting forces are accounted. The disturbances are presented in a form of linear functions of time. The presented modeling results confirm the correctness of the theoretical conclusions.

The article addresses the problem of controlling a vehicle in an undetermined 3D environment with mobile and stationary obstacles. We propose a two-level system performing planning and path-following. The path planning problem is split into the problem of planning and following global paths-missions and the problem of local planning in an obstructed area. The global path is built based on a priory information. A local path corrects the global one if the system detects obstacles that are not presented on the map. At first, the system is proposed that follows the global path at the controller level. Secondly, the hybrid system is introduced. It avoids obstacles using unstable modes at the lower level together with an intelligent algorithm determining the desired direction of detour at the top level. The techniques of introducing unstable modes are analyzed. Numerical modeling results are presented using the example of a hexacopter control system.

The article presents development and analysis of hybrid path planning systems for vehicles. Two types of planner structures were defined. In the first type of systems several basic path planning methods operate together. In the systems of the second type parameters and initial data of one basic method are modified by additional algorithms. We developed a controller that solves positioning and path-following problems with a high accuracy. A hybrid path-planning system is developed for a hexacopter based on the virtual fields method in the class of hybrid systems of the second type. In the synthesized system a special algorithm of sensor data analysis modifies the initial data to use the virtual fields method.

This paper presents homing and docking autopilot design for the autonomous underwater vehicle (AUV). A nonlinear interrelated dynamic model of the underwater vehicle is considered. The AUV autopilot is designed on base of a position-trajectory control method. Adaptation of the control system is based on robust disturbances estimation. Modeling and hardware results approved feasibility of the proposed methods.

The problem of decentralized control of group of robots, described by kinematic and dynamic equations of motion in the plane, is considered. Group performs predetermined rectangular area passing at a fixed speed, keeping the line and a uniform distribution. The environment may contain a priori unknown moving or stationary obstacles. Decentralized control algorithms, based on the formation of repellers in the state space of robots, are proposed. These repellers form repulsive forces generated by dynamic subsystems that extend the state space of robots. These repulsive forces are dynamic functions of distances and velocities of robots in the area of operation of the group. The process of formation of repellers allows to take into account the dynamic properties of robots, such as the maximum speed and acceleration. The robots local control law formulas are derived based on positionally-trajectory control method, which allows to operate with non-linear models. Lyapunov function in the form of a quadratic function of the state variables is constructed to obtain a nonlinear closed-loop control system. Due to the fact that a closed system is decomposed into two independent subsystems Lyapunov function is also constructed as two independent functions. Numerical simulation of the motion of a group of five robots is presented. In this simulation obstacles are presented by the boundaries of working area and a movable object of a given radius, moving rectilinear and uniform. Obstacle speed is comparable to the speeds of the robots in a group. The advantage of the proposed method is ensuring the stability of the trajectories and consideration of the limitations on the speed and acceleration at the trajectory planning stage. Proposed approach can be used for more general robots’ models, including robots in the three-dimensional environment.

This chapter is devoted to genetic algorithms (GAs) for mobile robot planning. Section 4.1 describes the complete algorithm for path planning and functioning of the GA and graphs as its part. Section 4.2 gives short overview of graph idea and how it is applied to represent the optimized path. Section 4.3 describes the GAs applied to path planning. Section 4.3.1 describes the general idea of GAs and basic genetic operators. Section 4.3.2 studies three modifications of the GA—classical, ( μ , λ ), and ( μ + λ ), and chooses the best one for the task of path planning. Section 4.4 the results of imitation modeling on the test bench common for all path planning methods in this book.

This chapter addresses an approach to vehicle motion control based on using unstable modes. We introduce a notion of bifurcation parameter that can transform the vehicle's motion trajectory in the vicinity of obstacles by transforming them into repellers. Based on the proposed approach, an algorithm of simultaneous control and path planning is suggested. The numerical modeling results are given for the test scenes and for the environments with mobile obstacles. The performed research resulted in a modified method of control and motion planning in obstructed environments based on joint usage of unstable mode and the concept of a virtual goal point. The unstable mode and the virtual point are cohered by the bifurcation parameter. Computer modeling was performed for the obtained algorithms. The proposed approach allowed for the vehicle's functioning in a complicated obstructed environment using only the information about the distance to the detected obstacles.

The first chapter presents an analysis of problems related to vehicle control. The introduced mathematical model is built based on solid body equations, which includes the equations of kinematics, dynamics, and actuators. The structure of the mathematical model of a solid body is described in a 3D environment. Using the general model, the vehicle's model is created for a wheeled cart which is used in modeling examples in the rest of the book. The flat test scenes are described and the positions of goals and obstacles are given. Mechanisms of planning the paths as a union of linear and quadratic forms being the functions of vehicle's external coordinates are presented in this chapter. A wheeled cart vehicle with a multilayered control system is considered. The solutions generated by the planning level are implemented using the synthesized motion-control algorithms. The requirements are formulated for the motion planners; and performance criteria are given to estimate the planning algorithms. The limitations on the sensors characteristics, actuators, and environment are discussed.

This paper is part of a series that describe the development and setup of intelligent underwater vehicle. Here we focus on the implementation tests for the identification of the actuating device parameters. An energy efficient type of glider is chosen with its block diagram presented. The assembled model is placed in a mini pool for movement tests with the objective of setting up the motors and pump. When put in neutral, its immersion and surfacing position show that there is interdependent between pump operation time, ballast bag maze, displacement of weight and glider attitude angle. These dependencies are described by linear equations and coefficients which are then identified.

The presented solution is a decentralized control system with a minimal informational interaction between the objects in the group. During control and path planning the obstacles are transformed into repellers by the synthesized controls. The main feature distinguishing the developed approach from the potential fields method is that the vehicle moves in the fields of forces depending not only on the mutual positions of a robot and an obstacle but also on the additional variables allowing solving the problem of robot’s path planning using a distributed control system (Pshikhopov and Ali, 2011). Unlike the work by Pshikhopov and Ali, 2011, here an additional dynamic variable is used to introduce stable and unstable states depending on the state variables of the robot and the neighboring objects. The local control system of each vehicle uses only the values of its own speeds and coordinates and those of the neighboring objects. There is no centralized control algorithm. In the local control algorithms the obstacles are represented as vehicles being a part of the group which allows us to unify the control systems for heterogeneous groups. An analysis was performed that proves existence and asymptotic stability of the steady state motion modes. The preformed simulation confirms the synthesis and analysis results.

Today, mobile objects are finding increasing usage in a wide variety of applications. Robots have been put to use in the air, on the ground and under the sea. Along with this expansion in robot technology, the problem of control and autonomous decision making is an ongoing concern, especially in light of the increasing difficulty of tasks. This study is focused on the algorithms of adaptive control system for mobile objects. The authors examined the application of direct adaptive control with reference to model approaches, in particular the position-path method. Point positioning is discussed, and the authors propose a method for efficiency improvement. Parametric uncertainty and influence of immeasurable disturbances are expected. Basic algorithms for the calculation of controlling forces and moments are synthesized using the position-path control method. The authors propose a structure and algorithms of an adaptive position-path system with a reference model. The synthesis of adaptive regulator and stability analysis of closed-loop system is performed, and an example of regulator synthesis is given. Finally, the authors present simulation results for an autonomous unmanned underwater vehicle equipped with a main engine, nose and hydrodynamic rudders on the tail. Along with this, horizontal and vertical maneuvering devices are presented.

This work is aimed at mathematical model of unmanned robotized airship. An airship can be controlled remotely by pilot or fly autonomously. Nonlinear interrelated model of an airship, considering kinematics and dynamics, main propulsion drives and ballonets is developed. Also mathematical model of external environment is presented. Results of CFD researches for aerodynamics are presented.