Diseño de un controlador de seguimiento para un sistema SISO de servoposicionamiento neumático

Pneumatic systems have many advantages, such as simplicity, reliability, low-cost, long life, etc. making them attractive for rapid development and widespread application, but the complexity of the airflow through the valve port and the friction between the cylinder and piston make it difficult to establish an exact mathematical model and control the pneumatic system with high precision. Experiments were conducted with a 25 mm bore rod-less pneumatic cylinder and a 5/3 way proportional control valve. In this contribution, I propose a nonlinear robust tracking control strategy to solve the tracking problem of the servo pneumatic positioning system. The approach is novel in the sense that it takes into account the nonlinearities inherent to pneumatic servo positioning systems and considers position, velocity and pressure difference in the chambers of the pneumatic cylinder as feedback states. The suggested control strategy is implemented in simulation and on the real system. Experimental results from an implementation on a test ring show a high position tracking control performance.Los sistemas neumáticos tienen varias ventajas que permitieron su rápido desarrollo y uso generalizado, tales como: simplicidad, confiabilidad, bajo costo, larga vida etc. Sin embargo, la complejidad del flujo de aire a través de los orificios de la válvula y la naturaleza de la fuerza de fricción entre las paredes del cilindro y el pistón, dificultan la obtención de modelos matemáticos exactos y el control de los sistemas neumáticos con alta precisión. Experimentos fueron llevados a cabo con un cilindro sin vástago de 25 mm de diámetro y una válvula de control proporcional de 5 puertos -3 vías. En este artículo, proponemos una estrategia de control de posicionamiento robusta para solucionar el problema de un sistema de servo posicionamiento neumático. El enfoque es novedoso en el sentido de que tiene en cuenta las no linealidades inherentes a los sistemas de servo posicionamiento neumático y considera posición, velocidad y diferencia de presiones en las cámaras del cilindro neumático como estados de retroalimentación.  La estrategia de control propuesta es implementada en simulación y sobre el sistema real. Los resultados experimentales de la implementación de la estrategia en el sistema de servo-posicionamiento  neumático muestran un alto desempeño en el control de seguimiento de posición

Design and simulation of a distortion masking control algorithm for a pneumatic cylinder

Low energy efficiency is one of the main detractors of fluid power technology. To ensure the availability and sustainability of energy sources, fluid power technology needs to meet high energy-efficiency and cost standards. This study aims to design, simulate and test a control algorithm that attenuates the detrimental effects of air compressibility on the performance and efficiency of a pneumatic cylinder. The transmission of power over long distances makes it more difficult for fluid power technology to meet energy-efficiency and cost requirements. Transmitting power over long distances represents a challenge particularly for pneumatics due to the compressibility of air. The compressibility of air transmitted through lengthy tubing decreases the performance and efficiency of pneumatic actuators, mainly affecting their time response and velocity. The system under analysis was composed of a pneumatic cylinder, two proportional control valves, and connective tubing. The dynamics of the individual components were characterized through experimentation. Nonlinear and linear models for the system were validated through the comparison of simulated and experimental data. The models predicted the system behavior more accurately at 2.5 Hz, when friction effects became negligible, as compared to 1.0 and 0.5 Hz. A controller was designed using pole/zero cancellation, a control strategy able to mask undesirable dynamics of the system being controlled. Pole/zero cancellation had superior performance in the attenuation of air compressibility effects in comparison to proportional and proportional-derivative (PD) control. System performance and efficiency were assessed in terms of the variation of the length of tubing connecting the pneumatic cylinder and the control valves. Pole/zero cancellation enabled the cylinder to achieve similar levels of performance for long (3.0 m) tubing as with short (0.55 m) tubing. With a 1.0-Hz sinusoidal input and equal control gains, pole/zero cancellation reduced the tracking error by approximately 30% and 23% in comparison to proportional and PD control, respectively. In terms of efficiency, with the system tracking a 2.5-Hz sinusoidal command, and using equal control gains, pole/zero cancellation increased the cylinder efficiency by approximately 36% and 54% in comparison to proportional and PD control, respectively. In general, pole/zero cancellation increased the system performance and efficiency in comparison to the other control schemes applied

Development of a Research Spacecraft Test-Bed with Implementation of Control Laws to Compensate Undesired Dynamics

The development of research spacecraft systems has a significant impact on the preparation and simulation of future space missions. Hardware, software and operation procedures can be adequately tested, validated and verified before they are deployed for the actual mission. In this thesis, a spacecraft vehicle test-bed named Extreme Access System (EASY) was developed. EASY aims at supporting validation and verification of guidance, navigation and control algorithms. Description of EASY spacecraft systems, sub-systems and integration is presented in this thesis along with an analysis of results from numerical simulation and actual implementation of control laws. An attitude control architecture based on quaternion feedback linearization is also described, and performance analysis in the compensation of undesired dynamics is presented. The results show the capabilities and potential of EASY to simulate missions that require validation and verification stages

Review On Controller Design In Pneumatic Actuator Drive System

A pneumatic actuator is a device that converts compressed air into mechanical energy to perform varieties of work. It exhibits high nonlinearities due to high friction forces, compressibility of air and dead band of the spool movement which is difficult to manage and requires an appropriate controller for better performance. The purpose of this study is to review the controller design of pneumatic actuator recommended by previous researchers from the past years. Initially, the basic views of the pneumatic will be presented in terms of introduction to the pneumatic actuator and its applications in industries. At the end of this review, discussions on the design of the controllers will be concluded and further research will be proposed along with the improvement of control strategies in the pneumatic actuator systems

Fuzzy practical exponential tracking of an electrohydraulic servosystem

Cilj ovog rada je da doprinese teorijskoj i praktičnoj primeni fazi logičkog upravljanja korišćenjem koncepta praktičnog praćenja. Predlaže se novi fazi upravljački algoritam za ostvarivanje željenog kvaliteta praćenja jednog elektrohidrauličkog pozicionog servosistema, koji se može naći u mnogim industrijskim uređajima. Fazi logički kontroler je jedan od najjednostavnijih. On koristi samo jednu ulaznu veličinu, sa linearnom metodom zaključivanja. Fazi prateći algoritam upravljanja je zasnovan na principu samoprilagodljivosti. Strukturna karakteristika takvog sistema upravljanja je postojanje dve povratne sprege: globalne, negativne po izlaznoj veličini i lokalne, pozitivne po upravljačkoj veličini. Takva struktura obezbeđuje sintezu upravljanja bez poznavanja unutrašnje dinamike objekta i bez merenja poremećajnih veličina. Predloženi fazi prateći algoritam upravljanja obezbeđuje promenu greške izlazne veličine po unapred definisanom eksponencijalnom zakonu. Prezentuju se rezultati simulacije nelinearnog matematičkog modela hidrauličkog servosistema.The aim of this paper is to contribute to the theoretical and practical applications of fuzzy logic control using practical tracking concept. A new fuzzy control algorithm is proposed to achieve the desired tracking performance of a nonlinear electrohydraulic position servo system, which can be found in many manufacturing devices. The fuzzy logic controller is one of the simplest. It employs only one input, with linear fuzzy inference method. The practical tracking control algorithm is based on the selfadjustment principle. The structural characteristic of such a control system is the existence of two feedback sources: the global negative of the output value and the local positive of the control value. Such a structure ensures the synthesis of the control without the internal dynamics knowledge and without measurements of disturbance values. The proposed fuzzy practical control algorithm ensures the change of the output error value according to a prespecified exponential law. The simulation results of the nonlinear mathematical model of the hydraulic servo system are presented

Fuzzy practical exponential tracking of an electrohydraulic servosystem

Cilj ovog rada je da doprinese teorijskoj i praktičnoj primeni fazi logičkog upravljanja korišćenjem koncepta praktičnog praćenja. Predlaže se novi fazi upravljački algoritam za ostvarivanje željenog kvaliteta praćenja jednog elektrohidrauličkog pozicionog servosistema, koji se može naći u mnogim industrijskim uređajima. Fazi logički kontroler je jedan od najjednostavnijih. On koristi samo jednu ulaznu veličinu, sa linearnom metodom zaključivanja. Fazi prateći algoritam upravljanja je zasnovan na principu samoprilagodljivosti. Strukturna karakteristika takvog sistema upravljanja je postojanje dve povratne sprege: globalne, negativne po izlaznoj veličini i lokalne, pozitivne po upravljačkoj veličini. Takva struktura obezbeđuje sintezu upravljanja bez poznavanja unutrašnje dinamike objekta i bez merenja poremećajnih veličina. Predloženi fazi prateći algoritam upravljanja obezbeđuje promenu greške izlazne veličine po unapred definisanom eksponencijalnom zakonu. Prezentuju se rezultati simulacije nelinearnog matematičkog modela hidrauličkog servosistema.The aim of this paper is to contribute to the theoretical and practical applications of fuzzy logic control using practical tracking concept. A new fuzzy control algorithm is proposed to achieve the desired tracking performance of a nonlinear electrohydraulic position servo system, which can be found in many manufacturing devices. The fuzzy logic controller is one of the simplest. It employs only one input, with linear fuzzy inference method. The practical tracking control algorithm is based on the selfadjustment principle. The structural characteristic of such a control system is the existence of two feedback sources: the global negative of the output value and the local positive of the control value. Such a structure ensures the synthesis of the control without the internal dynamics knowledge and without measurements of disturbance values. The proposed fuzzy practical control algorithm ensures the change of the output error value according to a prespecified exponential law. The simulation results of the nonlinear mathematical model of the hydraulic servo system are presented