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Realization of biologically motivated algorithms in industrial applications is becoming a new research, especially in the field of electrohydraulic systems. One of the recent innovations named brain emotional learning–based intelligent controller has been catching eyes of the researcher as a model-free adaptive controller, which has effective capabilities to handle nonlinearities and uncertainties of controlled systems. The aim of this article is to develop a so-called self-tuning brain emotional learning–based intelligent controller for tracking control of electrohydraulic actuators. Here, the main control unit brain emotional learning–based intelligent controller is used to drive the system to desired targets. Meanwhile, a fuzzy inference is designed to tune online the reward function (RF) parameter of the brain emotional learning–based intelligent controller, which enables the system robustness and stability. A test rig employing an electrohydraulic actuator is then setup to investigate the system control performance. The experimental results implied that proposed controller has strong ability to drive the system to follow different reference trajectories with minimal errors.

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Abstract:In recent hydraulic actuation systems, conventional hydraulic spool valves with pressure compensators are becoming less popular, after the introduction of the independent metering concept for valves. Within this concept, four valves are needed for actuating a single cylinder. Subsequently, this increases the freedom of controlling both chamber pressures of the cylinder, and it then provides for electronically-controlled pressure compensation facilities. Additionally, this has the potential to save valuable energy. The primary focus of this paper is to develop a new generation of hydraulic circuits using the independent metering valve (IMV). This configuration can function well as a conventional IMV circuit while providing better pressure control. We first describe the working principles of five distinct modes of the proposed IMV system. Then, mathematical models for each working mode are presented. Finally, we present numerical simulations that have been carried out to evaluate the system performance, in comparison with that of the conventional IMV configuration. The simulation results demonstrate that the performance of the new IMV configuration is superior to the conventional IMV system in terms of energy savings.

Recent research on hydraulic systems has mainly focused on energy saving. This is because the efficiency of hydraulic systems is very low even though they have large power-to-size ratios. In mobile hydraulic equipment, conventional hydraulic spool valves with pressure compensators have already been replaced by valve assemblies with four-valve independent metering with electronically controlled pressure compensation. The independent metering concept and microprocessor control have much more potential to save more energy than conventional proportional valve control because of the increased controllability of the system. The primary focus of this study is to reduce the number of Independent Metering Valves (IMV) by introducing one directional control valve. This new model offers two degrees of freedom, i.e., controlling velocity and pressure, just as in conventional IMVs. In the system described here, two of the three independent valves are active during metering. In this paper, the theory behind a new method of flow control based upon load feedback is presented for two of the five distinct metering modes, and its performance is investigated and compared to that of a conventional IMV configuration.

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