Model-Based Control Design of an EHA Position Control Based on Multicriteria Optimization

For the control of dynamic systems such as an Electro-Hydraulic Actuator (EHA), there is a need to optimize the control based on simulations, since a prototype or a physical system is usually not available during system design. In consequence, no system identification can be performed. Therefore, it is unclear how well a simulation model of an EHA can be used for multicriteria optimization of the position control due to the uncertain model quality. To evaluate the suitability for control optimization, the EHA is modeled and parameterized as a grey-box model using existing parameters independent of test bench experiments. A method for multi-objective optimization of a controller is used to optimize the position control of the EHA. Finally, the step responses are compared with the test bench. The evaluation of the step responses for different loads and control parameters shows similar behavior between the simulation model and the physical system on the test bench, although the essential phenomena could not be reproduced. This means that the model quality achieved by modeling is suitable as an indication for the optimization of the control by simulation without a physical system

Control de fuerza en actuadores hidráulicos mediante válvula de alivio proporcional

El control de fuerza tratado en el presente trabajo es aplicado en actuadores hidráulicos mediante una válvula de alivio proporcional. Inicia con una revisión bibliográfica sobre algunas aplicaciones industriales y artículos de carácter investigativo. De acuerdo con ciertas necesidades académicas y los elementos disponibles en el Laboratorio de Sistemas Dinámicos, se optó por el modelo de control de fuerza por medio de una válvula proporcional de alivio. Dada la importancia de las válvulas proporcionales se hizo necesario realizar la caracterización y verificación del comportamiento de este componente, con el fin de evaluar su condición de funcionamiento. Posteriormente se adicionaron los demás elementos necesarios para completar el sistema y se estableció la comunicación e interacción de las señales presentes, obtenidas mediante un módulo de adquisición de datos (NI-USB 6008). El tratamiento de las señales y el control sobre la válvula proporcional de alivio se efectuó mediante el software LabVIEW, previa simulación del sistema en Matlab y la retroalimentación de la planta fue implementada mediante una celda de carga que registra la fuerza ejercida por el actuador; concluyendo con ello la implementación del control de fuerza en cilindros hidráulicos

Advanced hydraulic systems for next generation of skid steer loaders

Fluid power systems have been extensively used in off highway applications like skid steer loaders, wheel loaders, excavators since many years. Work has been done by both industry and academia to improve efficiency, reduce noise and leakages in these systems. With increasing competition in the market, importance is now also given to operator comfort and machine productivity in off highway applications. Mobile, off – highway vehicles like Skid-steer loaders are widely used in labour saving applications like loading earth into a truck, dig and move material on construction sites to, clean roads, clear snow from roads etc. To carry out these jobs in limited spaces, skid steer loaders need tight turning radius. For this reason, these machines have a short wheelbase which prevents the use of suspensions in these vehicles. The absence of a suspension system exposes the vehicle to ground vibrations of high magnitude and low frequency. Vibrations reduce operator comfort, productivity and life of components. This thesis will discuss control strategies for vibration damping of skid steer loader using the hydraulic boom cylinder as the active suspension element, which is equivalent to a spring–damper. Along with vibrations, the machine productivity is also hampered by material spillage which is caused by the tilting of the bucket due to the extension of the boom. This dissertation will discuss the development of a robust path-planning control algorithm which adapts to the position of the boom to maintain a level load to achieve bucket self-leveling. Another reason for reduced productivity in skid steer loaders is slow in site travel speeds. This dissertation also concentrates on reducing the in-job cycle time by developing a control strategy to smooth speed shift the drive motors keeping the pump flow constant. To synthesize these proposed control algorithms, high fidelity hydraulic and mechanical models of the skid steer loader are created. Ultimately, the control algorithms derived in this dissertation help in improving operator comfort and machine productivity

Finite-Time Composite Position Control for a Disturbed Pneumatic Servo System

This paper investigates the finite-time position tracking control problem of pneumatic servo systems subject to hard nonlinearities and various disturbances. A finite-time disturbance observer is firstly designed, which guarantees that the disturbances can be accurately estimated in a finite time. Then, by combining disturbances compensation and state feedback controller together, a nonsmooth composite controller is developed based on sliding mode control approach and homogeneous theory. It is proved that the tracking errors under the proposed composite control approach can be stabilized to zero in finite time. Moreover, compared with pure state feedback control, the proposed composite control scheme offers a faster convergence rate and a better disturbance rejection property. Finally, numerical simulations illustrate the effectiveness of the proposed control scheme

Control de fuerza en actuadores hidráulicos mediante válvula de alivio proporcional

El control de fuerza tratado en el presente trabajo es aplicado en actuadores hidráulicos mediante una válvula de alivio proporcional. Inicia con una revisión bibliográfica sobre algunas aplicaciones industriales y artículos de carácter investigativo. De acuerdo con ciertas necesidades académicas y los elementos disponibles en el Laboratorio de Sistemas Dinámicos, se optó por el modelo de control de fuerza por medio de una válvula proporcional de alivio. Dada la importancia de las válvulas proporcionales se hizo necesario realizar la caracterización y verificación del comportamiento de este componente, con el fin de evaluar su condición de funcionamiento. Posteriormente se adicionaron los demás elementos necesarios para completar el sistema y se estableció la comunicación e interacción de las señales presentes, obtenidas mediante un módulo de adquisición de datos (NI-USB 6008). El tratamiento de las señales y el control sobre la válvula proporcional de alivio se efectuó mediante el software LabVIEW, previa simulación del sistema en Matlab y la retroalimentación de la planta fue implementada mediante una celda de carga que registra la fuerza ejercida por el actuador; concluyendo con ello la implementación del control de fuerza en cilindros hidráulicos

Volume 3 – Conference

We are pleased to present the conference proceedings for the 12th edition of the International Fluid Power Conference (IFK). The IFK is one of the world’s most significant scientific conferences on fluid power control technology and systems. It offers a common platform for the presentation and discussion of trends and innovations to manufacturers, users and scientists. The Chair of Fluid-Mechatronic Systems at the TU Dresden is organizing and hosting the IFK for the sixth time. Supporting hosts are the Fluid Power Association of the German Engineering Federation (VDMA), Dresdner Verein zur Förderung der Fluidtechnik e. V. (DVF) and GWT-TUD GmbH. The organization and the conference location alternates every two years between the Chair of Fluid-Mechatronic Systems in Dresden and the Institute for Fluid Power Drives and Systems in Aachen. The symposium on the first day is dedicated to presentations focused on methodology and fundamental research. The two following conference days offer a wide variety of application and technology orientated papers about the latest state of the art in fluid power. It is this combination that makes the IFK a unique and excellent forum for the exchange of academic research and industrial application experience. A simultaneously ongoing exhibition offers the possibility to get product information and to have individual talks with manufacturers. The theme of the 12th IFK is “Fluid Power – Future Technology”, covering topics that enable the development of 5G-ready, cost-efficient and demand-driven structures, as well as individual decentralized drives. Another topic is the real-time data exchange that allows the application of numerous predictive maintenance strategies, which will significantly increase the availability of fluid power systems and their elements and ensure their improved lifetime performance. We create an atmosphere for casual exchange by offering a vast frame and cultural program. This includes a get-together, a conference banquet, laboratory festivities and some physical activities such as jogging in Dresden’s old town.:Group 8: Pneumatics Group 9 | 11: Mobile applications Group 10: Special domains Group 12: Novel system architectures Group 13 | 15: Actuators & sensors Group 14: Safety & reliabilit