Electro-hydraulic servo system adaptive robust control method based on low-frequency learning

Abstract

The invention discloses an electro-hydraulic servo system adaptive robust control method based on low-frequency learning. The method comprises a step of establishing a mathematical model of a hydraulic system and making the following assumptions that the total interference of the system is sufficiently smooth such that the total interference exists and is bounded, a desired position trajectory isthree-order derivable and is bounded, the uncertainty change range of parameters is bounded, and decreasing function absolute value and integral about time are smaller than a predetermined value, a step of constructing an adaptive robust low-frequency learning controller, based on a traditional backstepping control method, integrating the ideas of adaptive control and expected compensation, andadding a correction term into a controller parameter self-adjustment law, and a step of proving stability by using the Lyapunov stability theory and obtaining a global asymptotic stability result of the system by using the Barbalat lemma. According to the method, high-frequency tremor caused by a high gain and the influence of measurement noise on the high tracking performance of the system are effectively avoided, and better tracking performance is obtained.

Description

technical field [0001] The invention relates to the technical field of electromechanical servo control, in particular to an adaptive robust control method for an electro-hydraulic servo system based on low-frequency learning. Background technique [0002] In modern industrial production, hydraulic systems are widely used in many heavy-duty mechanical equipment such as cranes and truck-mounted cranes to ensure fast and heavy-duty operation. Hydraulic (such as hydraulic motor and hydraulic cylinder) system eliminates some mechanical transmission problems related to gears, such as backlash, strong inertial loads, etc., and these nonlinear problems are the main factors affecting system performance, and their existence will affect the system. Therefore, the advanced controller design of the hydraulic system can obtain high-precision control performance. However, when designing the controller of the hydraulic system, it is necessary to face many modeling uncertainties, such as pa...

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Problems solved by technology

However, the discontinuous controller designed by the classical sliding mode control is likely to cause the flutter problem of the sliding mode surface, thereby deteriorating the tracking performance of the system; the adaptive control method is a very effective method for dealing with parameter uncertainty, and can obtain gradual Steady-state performance for close tracking

However, uncertain nonlinearities such as external load disturbances are insufficient. When the uncertain nonlinearities are too large, the system may be unstable.

However, there are uncertain nonlinearities in the actual hydraulic system, so the adaptive control method cannot obtain high-precision control performance in practical applications; the adaptive robust control method is proposed, and the control method is uncertain in two kinds of modeling. The system can obtain definite transient and steady-state performance under the condition that the characteristics exist at the same time. To obtain high-precision tracking performance, it is necessary to increase the feedback gain to reduce the tracking error. However, too large feedback gain will increase the frequency of the closed-loop system. Wide, which may stimulate the high-frequency tremor of the system to destabilize the system, thereby deteriorating the control performance, and even causing system instability. Therefore, the traditional adaptive robust control method has certain engineering limitations.

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