Fuzzy unknown observer-based robust adaptive path following control of underactuated surface vehicles subject to multiple unknowns

In this paper, an alternative method to predict the noise of a submersible Axial Piston Pump (APP) for different valve seat materials is presented. The proposed method is composed of an Artificial Neural Network (ANN) model trained using experimental data and integrated with a hybrid algorithm consists of Cat Swarm Optimization (CSO) and Firefly Algorithm (FA) algorithms. The hybrid CSFA algorithm is used as a subroutine in the ANN model to estimate the ANN weights. The FA is used as local operator to improve the exploitation ability of CSO. The obtained results prove the excellence of the proposed method in predicting the noise of APP considering four different valve seat materials (Polytetrafluoroethylene (PTFE), Polyetheretherketone (PEEK), Aliphatic polyamides (NYLON), and stainless steel (316 L)), five speed levels, and six system pressures. Moreover, the effects of different mechanical properties of the valve seat materials as well as operating conditions (speed and system pressure) have been investigated.

Noise prediction of axial piston pump based on different valve materials using a modified artificial neural network model

This paper investigates the problem of nonlinear path following control of underactuated marine vehicles in the horizontal plane. Firstly, appropriate kinematic and dynamic models are established, where the kinematic model is developed in terms of the relative velocity with respect to the ocean current disturbances, and the dynamic model is developed to include the effects of wind and wave disturbances. Based on the time delay control method and the reduced-order linear extended state observer (LESOs) technique, an improved compound line-of-sight (CLOS) guidance law is first proposed which can estimate the unknown sideslip angle and can compensate for the effects of time-varying ocean currents. Secondly, the control law is decomposed into the kinematic and dynamic controllers by the back-stepping technique. The high-order tracking differentiator is applied to construct derivatives of desired yaw angle, which are calculated by the CLOS guidance law. This approach resolves the problem of computational complexity inherent in the traditional back-stepping method and simplifies the overall controller. The lumped disturbances caused by waves and wind are estimated and compensated by the reduced-order LESOs. Finally, stability analysis of the closed-loop system is performed. The simulation results and comparative analysis validate the effectiveness and robustness of the proposed control approach.

Compound line-of-sight nonlinear path following control of underactuated marine vehicles exposed to wind, waves, and ocean currents

A numerical investigation in characteristics of flow force under cavitation state inside the water hydraulic poppet valves

In this work, WC–10Co–4Cr coatings were separately deposited on 300M steel by high-velocity oxygen fuel (HVOF) and high-velocity air fuel (HVAF) spraying processes. Microstructure, porosity, micro-hardness, bonding strength, wear and corrosion resistance of the coatings after different processing were investigated and compared. The result shows that dense and homogeneous microstructure existed in both two WC–10Co–4Cr coatings. Owing to lower temperature flames and higher particle velocity in the HVAF process, the HVAF-sprayed WC–10Co–4Cr coating exhibited less decarburisation, lower porosity (0.74%), higher micro-hardness (1162 HV0.3) and bonding strength (74.68 MPa) than HVOF-sprayed WC–10Co–4Cr coating. In addition, wear and corrosion resistance of these two coatings were evaluated by sliding wear test and electrochemical corrosion test. The HVAF-sprayed WC–10Co–4Cr coating also exhibited excellent wear resistance and superior corrosion property than HVOF-sprayed WC–10Co–4Cr coating.

A comparative study on wear and corrosion behaviour of HVOF- and HVAF-sprayed WC–10Co–4Cr coatings

Study on the control methods of a water hydraulic variable ballast system for submersible vehicles

Effect of materials on the noise of a water hydraulic pump used in submersible

Improving the performance of an AUV hovering system by introducing low-cost flow rate control into water hydraulic variable ballast system

Natural water is widely used as working or lubricating medium instead of the traditional oil. Hard materials have potential application to solve the abrasive wear caused by the silt suspending in natural water and poor lubrication of water. As the candidate materials can worked in water, the tribological characteristics of the tribological properties of high velocity oxy-fuel (HVOF) spraying WC–10Co–4Cr coating combined with sintered Si 3 N 4 were investigated under different natural water lubrication, including natural silt-laden and filtered water from sea and river. In addition, distilled water was used as typical water lubricants to study the effect on the tribological behaviours. The tribological results of the tribopair exhibit excellent friction and wear resistance behaviours under the natural waters. The average steady-state friction coefficients of the tribopair under natural water are below 0.009, whilst the average wear rates under all natural waters are below 9 × 10 − 12  cm 3 /(N·m) for both materials. The results indicate that the WC–10Co–4Cr/Si 3 N 4 tribopair owns wider applicability to different natural waters. The water hydraulic components with this tribopair can work in different water areas in word, even unfiltered natural waters as pressure medium.

Yinshui Liu

Papers

A numerical investigation in characteristics of flow force under cavitation state inside the water hydraulic poppet valves

Study on the control methods of a water hydraulic variable ballast system for submersible vehicles

Effect of materials on the noise of a water hydraulic pump used in submersible

Improving the performance of an AUV hovering system by introducing low-cost flow rate control into water hydraulic variable ballast system

The applicability of WC–10Co–4Cr/Si3N4 tribopair to the different natural waters