Output Feedback Control for Active Suspension Electro-Hydraulic Actuator Systems With a Novel Sampled-Data Nonlinear Extended State Observer

Abstract

In this paper, an output feedback controller based on a novel sampled-data nonlinear extended state observer (SDNLESO) is proposed for an active suspension electro-hydraulic actuator (ASEHA) system to address the heavy nonlinearities, model uncertainties and sampled-data behavior. The designed controller only requires little prior knowledge about the controlled system for the purpose of position tracking. The SDNLESO, integrating a novel nonlinear extended state observer and an output predictor, is developed to simultaneously and continuously estimate the unmeasurable states and total disturbance for an error dynamic system rather than the original ASEHA system, where the actual discrete displacement tracking error between measurement output and the reference signal serves as the observer input. Then, a compensated controller is synthesized based on the obtained estimates, which is robust against the matched and mismatched disturbances of the system while being able to ensure an expected transient tracking performance and final tracking accuracy. By constructing weighted error system and using the geometric homogeneity theory, the SDNLESO convergence is proven, while the maximum allowable sampling period is derived theoretically for guiding the selection of the actual sampling interval. Moreover, the closedloop system stability and the tracking error exponential convergence are guaranteed within the Lyapunov framework. Finally, a number of practical experiments are carried out on the ASEHA system test platform. The results show that the proposed control method is applicable and valid for nonlinear and uncertain ASEHA system despite the existence of a large actuator area ratio. INDEX TERMS Active suspension elctro-hydraulic actuator (EHA), nonlinearity, output feedback, sampled-data observer, uncertainty.

Robust Finite-Time Convergence Control Mechanism for High-Precision Tracking in a Hybrid Fluid Power Actuator

“…where p  is the pressure drop level, A is the function of the opened area of the outlet port, which is calculated as The requirements of varied pressure inside the brake chamber lead to an imbalance in designing the directional servo valve. According to (5), an increase in hydraulic pressure in the entire brake chamber coincides with the connection of ports P and B in the proportional directional valve. In case A, the brake pressure surge over time can be computed as…”

“…Moreover, the reduction in brake pressure coincides with the positive value of the servo valve spool displacement. Therefore, the dynamic system modeling that involves (1) and (5)(6)(7)(8)(9) is deemed reliable.…”

“…High-precision gain-scheduled acceleration is used by various industries in crash simulations [1], safety tests [2], absorbance system design [3], deconstruction machines, and dummy tests [4]. Fluid power control, which uses electro-hydraulic system [5] and pneumatic control technologies [6], has attracted the attention of academics and industrial practitioners for many decades. Rapidly decelerating an actuator has a great impact on the external mass and internal reaction force inside the system.…”

“…In a control strategy with a dynamic system (1), (5)(6)(7)(8)(9), an input command signal (voltage) is sent to the servo valve to control the spool movement. Spool displacement determines the level of hydraulic pressure inside a brake chamber and controls the movement of a pneumatic piston.…”

Model‐free linear active disturbance rejection output feedback control for electro‐hydraulic proportional system with unknown dead‐zone

“…However, the practical problem is that most of the control algorithms mentioned above require full state feedback, which means more sensors are needed. Such conditions cannot be met in many cases, limited by cost and installation restrain [19]. To solve this problem, the output feedback control method has been extensively investigated.…”