Self-Collision Avoidance Control of Dual-Arm Multi-Link Robot Using Neural Network Approach

The problem of mutual collisions of manipulators of a dual-arm multi-link robot (so-called self-collisions) arises during the performance of a cooperative technological operation. Self-collisions can lead to non-fulfillment of the technological operation or even to the failure of the manipulators. In this regard, it is necessary to develop a method for online detection and avoidance of self-collisions of manipulators. The article presents a method for detecting and avoiding self-collisions of multi-link manipulators using an artificial neural network by the example of the dual-arm robot SAR-401. A comparative analysis is carried out and the architecture of an artificial neural network for self-collisions avoidance control of dual-arm robot manipulators is proposed. The novelty of the proposed approach lies in the fact that it is an alternative to the generally accepted methods of detecting self-collisions based on the numerical solution of inverse kinematics problems for manipulators in the form of nonlinear optimization problems. Experimental results performed based on MATLAB model, the simulator of the robot SAR-401 and on the real robot itself confirmed the applicability and effectiveness of the proposed approach. It is shown that the detection of possible self-collisions using the proposed method based on an artificial neural network is performed approximately 10 times faster than approaches based on the numerical solution of the inverse kinematics problem while maintaining the specified accuracy

The modeling of an anthropomorphic robot arm

This paper considers the anthropomorphic manipulator kinematics modeling problem. The considered anthropomorphic robot SAR-400 manipulator with five-fingered gripper has twelve degrees of freedom. In the paper the robot SAR-400 arm kinematic model and the simulation results are presented

Feedback linearized trajectory-tracking control of a mobile robot

This paper is devoted to the designing of a trajectory-tracking control system for a unicycle-type mobile robot. Synthesis of the trajectory control law is based on the feedback linearization method and a canonical similarity transformation of nonlinear affine system in state-dependent coefficient form. The result of experimental test of the trajectory control system for mobile robot Rover5 is presented

Marine Internet of Things Platforms for Interoperability of Marine Robotic Agents: An Overview of Concepts and Architectures

The creation of a Marine Internet of Things platform, including the Underwater Internet of Things, is needed to ensure the interaction and digital navigation of heterogeneous marine robotic agents. It is necessary to combine the following robotic agents: autonomous underwater vehicles, remotely operated vehicles, active and passive marine sensors, buoys, underwater sonar stations, coastal communication posts, and other elements of the platform. To ensure the interaction of all these elements, it is necessary to use a common communication system within the platform, as well as a common navigation and control system to solve complex problems of the navigation and control of the movement of robotic agents in order to implement a joint mission to collect and transmit data, including video information in real time. The architecture of the Marine Internet of Things platform must first be defined in order to use a unified approach to data exchange. This article provides an overview of approaches to determining the architectures of network underwater and marine communication systems based on the concept of the Internet of Things. This paper provides a comprehensive study of MIoT applications, challenges, and architectures. The main contributions of this paper are summarized as follows: we introduce potential MIoT applications; we point out the challenges of MIoT (i.e., the differences between MIoT and IoT); and we analyze the MIoT system architecture

Profiles of critical states in diagnostics of controlled processes

The forecasting problem of critical states of controlled processes is considered. The large deviations of controlled process from some regular state is the basis of forecasting. The main tool for the analysis of large deviations and prediction of critical states is asymptotic methods. The forecasting problem is reduced to the Lagrange-Pontryagin optimal control problem that in some conditions has a unique solution in the form of quasipotential. Based on quasipotential it is possible to build an effective prediction of critical states of controlled process

Profiles of critical states in diagnostics of controlled processes

The forecasting problem of critical states of controlled processes is considered. The large deviations of controlled process from some regular state is the basis of forecasting. The main tool for the analysis of large deviations and prediction of critical states is asymptotic methods. The forecasting problem is reduced to the Lagrange-Pontryagin optimal control problem that in some conditions has a unique solution in the form of quasipotential. Based on quasipotential it is possible to build an effective prediction of critical states of controlled process

Design and Modeling of an Experimental ROV with Six Degrees of Freedom

With the development of underwater technology, it is important to develop a wide range of autonomous and remotely operated underwater vehicles for various tasks. Depending on the problem that needs to be solved, vehicles will have different designs and dimensions, while the issues surrounding reduced costs and increasing the functionality of vehicles are relevant. This article discusses the development of inspection class experimental remotely operated vehicles (ROVs) for performing coastal underwater inspection operations, with a smaller number of thrusters, but having the same functional capabilities in terms of controllability (as vehicles with traditionally-shaped layouts). The proposed design provides controllability of the vehicle in six degrees of freedom, using six thrusters. In classical design vehicles, such controllability is usually achieved using eight thrusters. The proposed design of the ROV is described; the mathematical model, the results of modeling, and experimental tests of the developed ROVs are shown

Multiloop Multirate Continuous-Discrete Drone Stabilization System: An Equivalent Single-Rate Model

The article discusses the UAV lateral motion stabilization system, as a MIMO multiloop multirate continuous-discrete system, specified in the form of an input–output model in the domain of discrete Laplace transform or in the form of a structural diagram. Approaches to the construction of equivalent T and NT single-rate models for MIMO multiloop multirate continuous-discrete systems are considered. Here, T is the largest common divisor of the sampling periods of the system, N is a natural number that is the smallest common multiple of the numbers characterizing the sampling periods of the system. The resulting impulse representations of the outputs of equivalent models are in the form of rational functions. The basis for the construction of these models is a matrix of sampling densities—a structural invariant of sampling chains. An example of the construction of the indicated matrix and an equivalent single-rate model are given. Obtaining equivalent single-rate models for MIMO multiloop multirate systems allows us to extend the methods of research and synthesis of MIMO continuous and continuous-discrete systems to a common theoretical base—the theory of polynomials and rational functions, which are typical elements of the description of these classes of systems

An Artificial Neural Network Approach for Solving Inverse Kinematics Problem for an Anthropomorphic Manipulator of Robot SAR-401

The paper proposes a new design of an artificial neural network for solving the inverse kinematics problem of the anthropomorphic manipulator of robot SAR-401. To build a neural network (NN), two sets were used as input data: generalized coordinates of the manipulator and elements of a homogeneous transformation matrix obtained by solving a direct kinematics problem based on the Denavi–Hartenberg notation. According to the simulation results, the NN based on the homogeneous transformation matrix showed the best accuracy. However, the accuracy was still insufficient. To increase the accuracy, a new NN design was proposed. It consists of adding a so-called “correctional” NN, the input of which is fed the same elements of the homogeneous transformation matrix and additionally the output of the first NN. The proposed design based on the correctional NN allowed the accuracy to increase two times. The application of the developed NN approach was carried out on a computer model of the manipulator in MATLAB, on the SAR-401 robot simulator, as well as on the robot itself

Design and Modeling of an Experimental ROV with Six Degrees of Freedom

With the development of underwater technology, it is important to develop a wide range of autonomous and remotely operated underwater vehicles for various tasks. Depending on the problem that needs to be solved, vehicles will have different designs and dimensions, while the issues surrounding reduced costs and increasing the functionality of vehicles are relevant. This article discusses the development of inspection class experimental remotely operated vehicles (ROVs) for performing coastal underwater inspection operations, with a smaller number of thrusters, but having the same functional capabilities in terms of controllability (as vehicles with traditionally-shaped layouts). The proposed design provides controllability of the vehicle in six degrees of freedom, using six thrusters. In classical design vehicles, such controllability is usually achieved using eight thrusters. The proposed design of the ROV is described; the mathematical model, the results of modeling, and experimental tests of the developed ROVs are shown