Electro-hydraulic Actuator System Research Articles

Electro-hydraulic Actuation System for Multi-speed Electrified Drivetrains

Electro-hydraulic Actuation System for Multi-speed Electrified Drivetrains

Adaptive fast-finite-time extended state observer design for uncertain electro-hydraulic systems

This paper presents the design of an adaptive fast-finite-time extended state observer for electro-hydraulic actuator systems. First, state variables and subsequently the system model are divided into three independent parts, and fast-finite-time state observers with adaptive gains are designed independently for each part, guaranteeing the fast uniformly ultimate boundedness of the estimation errors. Then, based on the designed state observers and without any knowledge about the upper bounds of uncertainties or their derivatives, supplementary adaptive observers are presented to estimate the uncertainties. Besides, the adaptive gains of both observers are adjusted based on the evaluation of the absolute value of the observation errors in a straightforward manner, where rigorous analyses of the proposed strategy are provided through the Lyapunov approach. Finally, comparative simulations with respect to some leading strategies are presented to analyze the effectiveness of the proposed observers, where the convergence of the estimation errors to a small neighborhood of zero can be achieved almost regardless of the initial conditions. Indeed, in contrast to the earlier finite-time approaches which only have a relatively fast convergence rate around the equilibrium points, the proposed adaptive framework can also improve the convergence rate for zones far from the equilibrium points. It is concluded that the proposed scheme can compete with other leading strategies, making it a qualified alternative approach in the observer design with noteworthy potential.

Failures Mapping for Aircraft Electrical Actuation System Health Management

This paper presents the different types of failure that may occur in flight control electrical actuation systems. Within an aircraft, actuation systems are essential to deliver physical actions. Large actuators operate the landing gears and small actuators adjust passenger seats. As developing, aircraft systems have become more electrical to reduce the weight and complexity of hydraulic circuits, which could improve fuel efficiency and lower NOx emissions. Electrical Actuation (EA) are one of those newly electrified systems. It can be categorized into two types, Electro-Hydraulic Actuation (EHA) and Electro-Mechanical Actuation (EMA) systems. Emerging electric and hydrogen fuel aircraft will rely on all-electric actuation. While electrical actuation seems simpler than hydraulic at the systems level, the subsystems and components are more varied and complex. The aim of the overall project is to develop a highly representative Digital Twin (DT) for predictive maintenance of electrical flight control systems. A comprehensive understanding of actuation system failure characteristics is fundamental for effective design and maintenance. This research focuses on the flight control systems including the ailerons, rudders, flaps, spoilers, and related systems. The study uses the Cranfield University Boeing 737 as the basis to elaborate the different types of actuators in the flight control system. The Aircraft Maintenance Manual (AMM) provides a baseline for current maintenance practices, effort, and costs. Equivalent EHA and EMA to replace the 737 systems are evaluated. In this paper, the components and their failure characteristics are elaborated in a matrix. The approach to model these characteristics in DT for aircraft flight control system health management is discussed. This paper contributes to the design, operation and support of aircraft systems.

Third-Order Robust Fuzzy Sliding Mode Tracking Control of a Double-Acting Electrohydraulic Actuator

In the industrial sector, an electrohydraulic actuator (EHA) system is a common technology. This system is often used in applications that demand high force, such as the steel, automotive, and aerospace industries. Furthermore, since most mechanical actuators' performance changes with time, it is considerably more difficult to assure its robustness over time. Therefore, this paper proposed a robust fuzzy sliding mode proportional derivative (FSMCPD) controller. The sliding mode controller (SMC) is accomplished by utilizing the exponential law and the Lyapunov theorem to ensure closed loop stability. By replacing the fuzzy logic control (FLC) function over the signum function, the chattering in the SMC controller has been considerably reduced. By using the sum of absolute errors as the objective function, particle swarm optimization (PSO) was used to optimize the controller parameter gain. The experiment results for trajectory tracking and the robustness test were compared with the sliding mode proportional derivative (SMCPD) controller to demonstrate the performance of the FSMCPD controller. According to the findings of the thorough study, the FSMCPD controller outperforms the SMCPD controller in terms of mean square error (MSE) and robustness index (RI). Keywords—tracking control, electrohydraulic actuator (EHA), robust control design, fuzzy sliding mode proportional derivative (FSMCPD), particle swarm optimization (PSO).

Disturbance observer-based nonlinear feedback control for position tracking of electro-hydraulic systems in a finite time

In this paper, a disturbance observer-based backstepping tracking control is designed for an electro-hydraulic actuator (EHA) system to estimate and track reference signals in a finite time. It is assumed that the system is uncertain with unknown upper bounds. Different from the existing ones, the proposed observer can deal with strong uncertainties in which the estimation error converges to an arbitrarily small neighborhood of zero in a finite time. Then, the disturbance observer-based backstepping tracking control is provided to compensate the uncertainties and estimation errors and to guarantee the finite-time tracking of the piston position toward the desired time-varying reference signal. The key idea is to employ a monotonically increasing function associated with the control objective to improve the control performance, where the finite-time boundedness criterion is guaranteed using Lyapunov stability analysis. Finally, the efficacy of the proposed robust scheme for the EHA system with unknown measurement noise is illustrated in numerical simulations as compared to a leading observer-based control strategy in the literature. It is shown that the proposed approach results in more accuracy and faster convergence than that in the literature, making it a qualified alternative approach with noteworthy potential.

Improved Third Order PID Sliding Mode Controller for Electrohydraulic Actuator Tracking Control

An electrohydraulic actuator (EHA) system is a combination of hydraulic systems and electrical systems which can produce a rapid response, high power-to-weight ratio, and large stiffness. Nevertheless, the EHA system has nonlinear behaviors and modeling uncertainties such as frictions, internal and external leakages, and parametric uncertainties, which lead to significant challenges in controller design for trajectory tracking. Therefore, this paper presents the design of an intelligent adaptive sliding mode proportional integral and derivative (SMCPID) controller, which is the main contribution toward the development of effective control on a third-order model of a double-acting EHA system for trajectory tracking, which significantly reduces chattering under noise disturbance. The sliding mode controller (SMC) is created by utilizing the exponential rule and the Lyapunov theorem to ensure closed-loop stability. The chattering in the SMC controller has been significantly decreased by substituting the modified sigmoid function for the signum function. Particle swarm optimization (PSO) was used to lower the total of absolute errors to adjust the controller. In order to demonstrate the efficacy of the SMCPID controller, the results for trajectory tracking and noise disturbance rejection were compared to those obtained using the proportional integral and derivative (PID), the proportional and derivative (PD), and the sliding mode proportional and derivative (SMCPD) controllers, respectively. In conclusion, the results of the extensive research given have indicated that the SMCPID controller outperforms the PD, PID, and SMCPD controllers in terms of overall performance.

Chattering Analysis of an Optimized Sliding Mode Controller for an Electro-Hydraulic Actuator System

Wear and tear are usually caused by various factors, which reduce the life span of a mechanical part. In the control engineering of an Electrohydraulic actuator system, the wear and tear can be caused by the system or the controller itself. This article examines the chattering effect that occurs during the sliding mode controller (SMC) design, and its effect on the nonlinear electrohydraulic actuator (EHA) system. To examine the chattering phenomenon, signum function is first applied on the switching function of the SMC. Then, parameters of the controller are obtained using single objective particle swarm optimization (PSO) method. These parameters are then applied to the switching function with hyperbolic tangent function. Lastly, the performance of both functions is analysed and compared based on graph and numerical data. From the output data, chattering phenomenon generated on the signum function is greatly eliminated by using hyperbolic tangent function.

Position Tracking Performance with Fine Tune Ziegler-Nichols PID Controller for Electro-Hydraulic Actuator in Aerospace Vehicle Model

Electro-Hydraulic Actuator (EHA) system is a third order non-linear system which is highly suffer from system uncertainties such as Coulomb friction, viscous friction and pump leakage coefficient which makes this system more complicated for the designing of the controller. The Proportional-Integral-Derivative (PID) controller has proposed in this paper to control EHA system and main problem in its application is to tune the parameter to its optimum value. Two different methods are used to tune the PID controller which are trial and error and Ziegler-Nichols method. MATLAB Simulink is used to simulate the system. In order to determine the performance of EHA system for the position tracking. 3 different of external disturbance such as 0N, 5000N and 10000N has been injected into the system. Simulation results show that the Ziegler-Nichols fine tuning method provides the better tracking performance when compared to the trial and error method for every specific disturbance setting. The Ziegler Nichols method provides better disturbance rejection as the performances indexes such as percentage overshoot, settling time and steady state error are not affected by the varying of disturbance.

Electrohydraulic proportional valve-controlled vane type semi-rotary actuated wind turbine control by feedforward fractional-order feedback controller

In this study, proportional valve-controlled semi-rotary electrohydraulic actuator proposed for horizontal axis wind turbine pitch movement. Semi-rotary actuator can be connected directly to the wind turbine blade, which reduces mechanical complexity compare to linear electrohydraulic actuator system. Adaptive torque control scheme has been adopted for the horizontal axis wind turbine in region II; however, adaptive pitch control has been adopted for region III. Optimum pitch demand and torque demand have been estimated through blade element momentum theory based on predicted wind speed. The control objective is to track maximum power through torque control in region II and to maintain rated power with structural safety by limiting thrust force in the region III. The proposed wind turbine model has been validated with 1.5-MW wind turbine experimental data. Feedforward fractional-order proportional–integral–derivative controller with adaptive teaching–learning based optimization algorithm has been developed for wind turbine control application. In region II, feedforward control signal generates due to torque demand and feedback control signal generates due to combined torque and pitch error. However, in region III, feedforward and feedback control estimated with pitch demand and combined pitch and torque error, respectively. The proposed controller performance has been tested with sinusoidal, step and actual wind data. The controller performance also compared with respect to other conventional controllers. Performance of the adaptive teaching–learning-based optimization has been compared with genetic algorithm and teaching–learning-based optimization process. Sensitivity analysis has been performed with proposed controller to check the effectiveness of the optimization. Furthermore, the proposed controller response has been compared with existing data of 1.5-MW wind turbine. Lyapunov-based stability analysis has been performed to ensure stability and convergence of the proposed system. Proposed controller performance has been found better compare to the existing result.

The Effects of Weightage Values with Two Objective Functions in iPSO for Electro-Hydraulic Actuator System

In this paper, the Proportional-Integral-Derivative (PID) controller with improved Particle Swarm Optimization (iPSO) algorithm is proposed for the positioning control of nonlinear Electro-Hydraulic Actuator (EHA) system. PID controller is chosen to control the EHA system due to its popularity in industrial applications. The PID controller parameters will be tuned by using the iPSO algorithm to get the lowest overshoot percentage and steady-state error. The conventional PSO algorithm has only one objective function to get the optimum parameters. However, this is not enough to increase the control performance of the EHA system. Therefore, an improved Particle Swarm Optimization (iPSO) that includes the mean error and overshoot percentage as the two objective functions is proposed in this paper. The most popular method in PSO that included two objective functions is Linear Weight Summation (LWS). In this method, the two objective functions are combined with certain weightage into one equation to give the best control performance. This paper focuses on determining the suitable weightage between these two objective functions so that the EHA system can produce the best control performance with less overshoot and less error. Overshoot percentage and steady-state error are used to indicate the best control performance. The results showed that EHA system can perform better by using suitable weightage between the mean error and overshoot percentage.

Active Disturbance Rejection Control for Position Tracking of Electro-Hydraulic Servo Systems under Modeling Uncertainty and External Load

In this paper, an active disturbance rejection control is designed to improve the position tracking performance of an electro-hydraulic actuation system in the presence of parametric uncertainties, non-parametric uncertainties, and external disturbances as well. The disturbance observers (Dos) are proposed to estimate not only the matched lumped uncertainties but also mismatched disturbance. Without the velocity measurement, the unmeasurable angular velocity is robustly calculated based on the high-order Levant’s exact differentiator. These disturbances and angular velocity are integrated into the control design system based on the backstepping framework which guarantees high-accuracy tracking performance. The system stability analysis is analyzed by using the Lyapunov theory. Simulations based on an electro-hydraulic rotary actuator are conducted to verify the effectiveness of the proposed control method.

DAIC Design for an Electro-Hydraulic Actuator via FASS-NLMS Algorithm

In this paper, it is proposed a new version of Normalized Least Mean Square (NLMS) algorithm, performed through a linguistic description based on the expert’s knowledge and implemented in a fuzzy rule base. In order to obtain a good trade-off between convergence speed and steady-state Mean Square Error (MSE) during the update of the estimate of the weights vector, it is used a Mamdani Fuzzy Inference System (MFIS) to adapt the step size of NLMS algorithm, whose inputs are the squared error and the normalized time instant. The validation of the proposed optimization algorithm was performed in Direct Adaptive Inverse Control (DAIC) design and applied to a non-minimum phase plant referring to an Electro-Hydraulic Actuator (EHA) system, shuch that a disturbance signal was added to the control signal.

Real time position control of electrohydraulic system using PID controller

In this paper, piston position of an electrohydraulic actuation system is controlled by implementing proportional integral derivative controller. At first, open loop technique is applied, and performance is observed. Secondly, closed loop method with proportional integral derivative controller is implemented and observed the transient and steady state parameters which shows better position control of the differential cylinder. The practical outcomes show that proportional integral derivative controller can track the reference trajectory within the operating range.

Automated Multi-Level Dynamic System Topology Design Synthesis

Designing new mechatronic systems for vehicle applications is a complex and time-consuming process. The increasing computational power allows us to generate automatically novel and new mechatronic discrete-topology concepts in an efficient manner. Using state-of-the-art computational design synthesis techniques assures that the complete search space, given a finite set of system elements, is processed to find all feasible topologies. The topology generation is done by converting the design synthesis problem into a constraint satisfaction problem. Accordingly, this mathematical problem is solved by assigning the presence of components and connections to variables, whereby a set of mathematical constraints need to be satisfied. These constraints capture, in essence, formalized engineering knowledge. After solving this problem, the results are post-processed to discard redundant topologies due to isomorphism. In this paper, a newly developed software application with automated constraint generation is presented that facilitates the topology generation with multiple system levels in a loop. The scalability of the problem and the different levels of expressiveness are analyzed, and the influence of the abstraction level choice on the search space is discussed. Finally, a relevant mechatronic design study from the automotive engineering field is discussed concerning the topology synthesis of alternative electro-hydraulic actuation systems being part of new continuously variable transmission topologies, thus showing its applicability.

A high-efficient solution for electro-hydraulic actuators with energy regeneration capability

This paper proposes a cost-effective, robustly practical solution for a high-efficient electro-hydraulic actuator (EHA) for linear drives. The solution addresses the challenges of high costs and limited efficiency that limit the application of EHA for the electrification of many off-road vehicles. Based on a variable-speed electric motor and a low-cost technology for a fixed-displacement pump, the proposed solution is suitable for a compact implementation and it is capable of energy regeneration under overrunning load conditions. Two different architectures—an open circuit and a closed circuit one—are considered to determine the most practical and efficient configuration as well as the control features. Both architectures minimize throttling losses associated with the conventional regulation of hydraulic actuators. Actuator velocities below the minimum and beyond the maximum allowable pump flow rate are achieved in both architectures using a proportional valve that bypasses the pump flow. The paper describes the design methodology as well as the simulation and experimental activities performed to verify the control strategies as well as energy efficiency. Considering an EHA system of about 20 kW, a complete efficiency map of the system is determined for all the possible four quadrants of operation thus including both resistive and overrunning loads, where energy recuperation is implemented. Simulation and experimental results show that the energy efficiency of the hydraulic systems can reach 84.7% in resistive phases. In assistive phases, the hydraulic system can recover up to 81.8% of the actuator energy. The comparison between open-circuit and closed-circuit structures shows the advantages of the former in terms of energy efficiency. The proposed solution is suitable for electrified hydraulic actuation systems, in both industrial and mobile applications. With the advantages of the low cost of the hydraulic unit and high energy efficiency, it is particularly suitable for mobile applications such as construction machines, that are recently experiencing a significant electrification trend.

Fault-tolerant synchronization control for a dual redundant electro-hydraulic actuator system based on velocity estimation

Fault-tolerant synchronization control for a dual redundant electro-hydraulic actuator system based on velocity estimation

Multi-Fault Diagnosis Approach Based on Updated Interacting Multiple Model for Aviation Hydraulic Actuator

The aviation hydraulic actuator (HA) is a key component of the flight control system in an aircraft. It is necessary to consider the occurrence of multiple faults under harsh conditions during a flight. This study designs a multi-fault diagnosis method based on the updated interacting multiple model (UIMM). The correspondence between the failure modes and the key physical parameters of HA is found by analyzing the fault mode and mechanism. The key physical parameters of HA can be estimated by employing a series of extended Kalman filters (EKF) related to the different modes of HA. The models in UIMM are updated once the fault is determined. UIMM can reduce the number of fault models and avoid combinatorial explosion in the case of multiple faults. Simulation results indicate that the multi-fault diagnosis method based on UIMM is effective for multi-fault diagnosis of electro-hydraulic servo actuation system.

Adaptive neural-bias-sliding mode control of rugged electrohydraulic system motion by recurrent Hermite neural network

This paper deals with design and implementation of a real-time position control scheme based on the synergistic combination of a recurrent neural network, an integral sliding mode controller and a bias controller for a rugged electrohydraulic actuation system. The controller design is based on recurrent Hermite neural network comprising a single hidden layer with orthonormal Hermite polynomial basis functions as activation functions for each hidden neuron and an integral sliding surface as the input. The bias controller is designed as a hyperbolic tangent of the error. Additionally, an adaptive scheme has been formulated based on the Lyapunov criterion and its convergence has been established. The performance of the proposed scheme has been evaluated on a laboratory scale single-rod electrohydraulic actuation system with a large dead band (∼10%) proportional valve in real-time. The experimental results suggest a significant improvement in the position tracking performance of the system for conventional tracking trajectories compared to other established methodologies.

Review of Advancement in Variable Valve Actuation of Internal Combustion Engines

The increasing concerns of air pollution and energy usage led to the electrification of the vehicle powertrain system in recent years. On the other hand, internal combustion engines were the dominant vehicle power source for more than a century, and they will continue to be used in most vehicles for decades to come; thus, it is necessary to employ advanced technologies to replace traditional mechanical systems with mechatronic systems to meet the ever-increasing demand of continuously improving engine efficiency with reduced emissions, where engine intake and the exhaust valve system represent key subsystems that affect the engine combustion efficiency and emissions. This paper reviews variable engine valve systems, including hydraulic and electrical variable valve timing systems, hydraulic multistep lift systems, continuously variable lift and timing valve systems, lost-motion systems, and electro-magnetic, electro-hydraulic, and electro-pneumatic variable valve actuation systems.

Proportional–Integral–Derivative Controller Design Using an Advanced Lévy-Flight Salp Swarm Algorithm for Hydraulic Systems

To improve the control ability of proportional–integral–derivative (PID) controllers and increase the stability of force actuator systems, this paper introduces a PID controller based on the self-growing lévy-flight salp swarm algorithm (SG-LSSA) in the force actuator system. First, the force actuator system model was built, and the transfer function model was obtained by the identification of system parameters identifying. Second, the SG-LSSA was proposed and used to test ten benchmark functions. Then, SG-LSSA-PID, whose parameters were tuned by SG-LSSA, was applied to the electro-hydraulic force actuator system to suppress interference signals. Finally, the temporal response characteristic and the frequency response characteristic were studied and compared with different algorithms. Ten benchmark function experiments indicate that SG-LSSA has a superior convergence speed and perfect optimization capability. The system performance results demonstrate that the electro-hydraulic force actuator system utilized the SG-LSSA-PID controller has a remarkable capability to maintain the stability and robustness under unknown interference signals.