Discrete dynamic simulation models and technique for complex control systems

Dynamic Control Design and Simulation of Biogas Pressurized Water Scrubbing Process

Computer-aided control system design (CACSD) encompasses a broad range of methods, tools, and technologies for system modelling, control system synthesis and tuning, dynamic system analysis and simulation, as well as validation and verification. The domain of CACSD enlarged progressively over decades from simple collections of algorithms and programs for control system analysis and synthesis to comprehensive tool sets and user-friendly environments supporting all aspects of developing and deploying advanced control systems in various application fields. This entry gives a brief introduction to CACSD and reviews the evolution of key concepts and technologies underlying the CACSD domain. Several cornerstone achievements in developing reliable numerical algorithms; implementing robust numerical software; and developing sophisticated integrated modelling, simulation, and design environments are highlighted.

Software simulation is one of the most common methods to study worm propagation. However, simulation process and software interface, which lack unified description, cause inefficiencies of worm propagation simulation. In order to achieve a unified description for worm propagation simulation process, we propose a Worm Propagation Simulation Description Language (WPSDL), which characterizes the software interfaces and parameters of each module in simulation process in a unified way. Meanwhile, we develop a simulation system of worm propagation oriented our presented language. In this system, we use related commands of the description language as interactive instructions, and then implement worm propagation simulation for different types of network worms. In addition, we conduct a series of experiments to analyse the impacts of worm propagation mechanism and network topology structure. The experiments show that increasing infection ability and scanning rate can improve the propagation scale significantly, and the propagation delay can influence the outbreak time and explosion intensity of worm propagation. The experiments not only provide support for the study of worm propagation mechanisms, but also verify the practicability of the description language and the simulation system.

This paper adopts the High Level Architecture to develop the space-based laser active imaging distribution simulation software system, and designs the system framework which contains three-step workflow including modeling, experimental and analysis. The paper puts forward the general needs of the simulation system first, then builds the simulation system architecture based on HLA and constructs 7 simulation federal members. The simulation system has the primary functions of space target scattering characteristic analysis, imaging simulation, image processing and target recognition, and system performance analysis and so on, and can support the whole simulation process. The results show that the distribution simulation system can meet the technical requirements of the space-based laser imaging simulation.

Fine-Grained Parallel and Distributed Spatial Stochastic Simulation of Biological Reactions

The problem of structural-parametric synthesis of automatic control systems (ACS) of technological objects is deter-mined by the multi-dimensionality, multi-connectedness and nonlinearity of their mathematical models. Despite the indicated properties of such objects, traditional linear systems based on PID-algorithms are still used for process control. Since the synthesis of linear systems using input-output models does not take into account the multi-dimensionality and mutual influence of state coordinates, such systems increase the influence of parametric and signal perturbations on the quality of control processes. The increasing requirements for the quality and efficiency of technological processes control made it expedient to apply the control principle by the state vector based on the use of uninertial state regulators or combined state regulators including flexible feedback on the derivative state coordinates or state coordinate integrals. The research uses methods of system analysis of technological processes as control objects, methods of automatic control theory, methods of control systems synthesis on the state regulators basis, meth-ods of computer simulation. The linearized mathematical model of liquid-phase chemical reactor in the state space has been obtained. It has been established that the investigated object has the property of free movement stability and it is fully controlled in the state space. The problem of synthesis of a single-channel concentration vector control system in a chemical reactor using state regulator has been solved. The parameters of state regulator settings have been determined using the method of modal control. The efficiency of the automatic control system on the basis of the state regulator with an integral component has been shown using the method of computer simulation of the ‘nonlinear object – linear control subsystem’ complex. It has been demonstrated that the absence of an integral component in the control algorithm structure leads to a great static error of regulation. To eliminate the static error of control and ensure the robustness of the control system, it is recommended to introduce an integral component into the structure of state controller. This ensures the efficiency of the control system both for the case of complete measurement of the state vector and for the case of measurement of the output controlled variable only.

The dynamic simulation system of a pantograph and a catenary has been built by using the finite element method, in which the pantograph is equivalent to a three-mass-damper-stiffness system and the catenary contains only cable and beam elements. Considering droppers as nonlinear elements only stressed by tension, a sliding contact model of the pantograph and catenary is coupled by penalty function. Nodal displacement and element stress can be obtained by direct time integration. Finally, the contact force and deformation of the pantograph and catenary is achieved by entering the parameters in standards and from the actual Wuhan–Guangzhou high-speed railway into this simulation system. When comparing the standards, commercial software and measured data, the credibility of the simulation system can be verified. This simulation system provides an efficient way for the design and structure optimization of a pantograph and catenary system.

Real-time digital simulation and graphic animation limited band-width dynamic control systems can significantly enhance the interpretation and understanding of system responses. This paper outlines an efficient techniques for generating the graphics and the timing in real-time simulation and animation of the dynamic control systems using a high-speed high- performance PC-AT microcomputer. For illustration, the simulation and animation results for the adaptive computer controlled suspension of a combat vehicle and for the gun-turret stabilization and tracking control system for combat vehicle are presented.

The increased availability of data and computer-aided technologies such as MRPI/II, ERP and MES system, allowing producers to be more adaptive to market dynamics and to improve production scheduling. Integration of production scheduling and computer modelling, simulation and visualization systems can be useful in the analysis of production system constraints related to the efficiency of manufacturing systems. A integration methodology based on semi-automatic model generation method for eliminating problems associated with complexity of the model and labour-intensive and time-consuming process of simulation model creation is proposed. Data mapping and data transformation techniques for the proposed method have been applied. This approach has been illustrated through examples of practical implementation of the proposed method using KbRS scheduling system and Enterprise Dynamics simulation system.

Project the integrated braking system for electric vehicles based on in-wheel motor and friction brake. Set up the integrated system dynamic model based on energy regenerative and feedback friction integrated braking. Come up with EBD control strategy on bisectional roads based on ABS system. Establish the dynamics simulation system and EBD control simulation system for the electric vehicles with the integrated braking system based on Matlab/Simulink. Simulate and analyze EBD control performance of the integrated braking system on bisectional road straight condition aimed at Chery A3 sedan. The study results indicate that the EBD control performance of electric vehicle with the integrated braking system has a high braking energy recovery ratio, braking efficiency and braking stability.

Design and validation of control strategies requires a knowledge of both control theory and the process to be controlled. These activities can be time consuming if a process is complex, involving many interacting equipments with non-linear characteristics. Simulators have proven to be a powerful tool in the design and validation of control structures for this type of complex process. The aim of this chapter is to describe a dynamic simulator for comminution plants implemented in a commercial simulation platform, and to illustrate its use in the design of control strategies for different stages in the comminution process.

Current simulation tools for multibody dynamics are not problem dependent, they use the same modeling process to all cases regardless of their characteristics. In addition, real-time simulation of small multibody systems is achievable by existing simulation tools, however, real-time simulation of large and complex systems is not possible with existing methods. This is a challenge that needs to be addressed before further advances in mechanical simulation with hardware-in-the-loop and man-in-the-loop, as well as virtual prototyping are made possible. This paper addresses the issue of how the modeling process-dependent versus independent coordinates, and descriptor form versus state-space form of the equations of motion-affects the dynamic simulation of multibody systems and how it may be taken into account and added to the concept of intelligent simulation. With this new concept all the factors involved in the simulation process — modeling, equations, solution, etc. — are chosen and combined depending upon the characteristics of the system to be simulated. It is envisioned that this concept will lead to faster and more robust real-time simulators.

Problem of synthesis of digital control system for a new-generation broad-band calibration testbed, operating in two regimes, is considered. The first low-velocity regime uses gyroscopic (float) angular velocity sensor together with the system of pendulum accelerometers, measuring tangential accelerations of the points of their attachment to the platform. The second high-velocity regime uses pendulum accelerometers only, part of these accelerometers recording tangential accelerations, and the other part, centrifugal accelerations. Similar to [1], the problem is connected with finding digital control algorithms realized in one processor which determine controllers of auxiliary loops (for angular velocity sensors and accelerometers) and the controller of the main loop (stabilization circuit) providing stabilization of the given motion of the controlled base platform. Solution to this problem is given; this solution represents the method for synthesis of such systems; analysis of obtained solution in the temporal and frequency domain is performed.

The paper is devoted to solving the problem of developing a synthesis method for combined position-force control systems (CS) for electric drives (ED) of multi-link underwater manipulators (MUM) mounted on autonomous underwater vehicles (AUV) operating in the mode of landing on the ground or on work sites, followed by rigid fixation of these AUV using special devices. To solve this problem, a comprehensive method is proposed in the first part of the paper. First, according to this method, a self-adjusting regulators are synthesized for the ED of each degree of freedom of the MUM, which makes it possible to stabilize its variable dynamic parameters at a given nominal level. This stabilization compensates for the influence of Coulomb and viscous friction, as well as part of the external torque caused by the mutual influences between the MUM links and their interaction with the viscous medium, on the quality of control. Then, to ensure the operation of the self-adjusting regulators and the ED CS, based on the initial nonlinear models of the ED, observers with a variable structure are synthesized to obtain information about the current values of external moments, as well as the rotation speeds and accelerations of all the ED output shafts. Using this information and measurements of only angle sensors of the specified output shafts, it was possible to synthesize position-force regulators for ED, minimizing the selected quadratic cost function, ensuring the specified movements of the output shafts of the item instance while creating the required moments. In the second part of the paper a synthesis of a combined position-force control system with all MUM elements was performed using these position-force regulators. As the results of computer modeling showed, this control system is capable of providing accurate movements of the MUM work tool along specified spatial trajectories and simultaneous creation of the required force effects on the work objects in the presence of the interaction of all its links with a viscous medium with variable parameters (viscous friction and added masses) while performing various complex technological operations.

Root-Locus Methods for Robust Control Systems Quality and Stability Investigations