The rapid-erection device is widely used in the engineering machinery and military field, such as dump truck and missile launching vehicle respectively. The hydraulic drive system is the core of the quick erecting device, so it is of great significance to diagnose its faults accurately. With the increase of the number of fault types, the accuracy of fault diagnosis of traditional BP neural network drops sharply, which is difficult to meet the engineering requirements. A fault diagnosis method based on BP neural network and AdaBoost algorithm is proposed for the hydraulic drive system of quick erecting device. Through the combination of BP neural network and step-by-step superposition modeling algorithm, a multi classification BP AdaBoost fault diagnosis model is established. Design the experimental system and set up 8 typical working conditions. The results show that the BP AdaBoost algorithm used in this paper has better classification performance than the traditional BP neural network method.

Soft actuators possessed highly flexible, complex environment adaptability and safe human-interaction. Firstly, in order to solve the limitation of stiffness control poorly of traditional soft actuators, based on the antagonistic mechanism of extensor and contractor muscles, a novel variable-stiffness fluid-driven soft actuator is proposed in this paper. The actuator can realize the composite action of elongation/contraction, and realize stiffness control by cooperatively adjusting the elongation and contraction forces. Secondly, based on the flexible deformation mechanism of the stretched and contracted fabrics, the mechanical model of the soft actuator is established and simulated. Finally, the mechanical properties of the actuator were tested under different pressures and deformation displacements, and the variable-stiffness characteristics of the actuator were verified. This research has significance to the research of soft actuator with variable stiffness.

In view of the traditional engineering equipment manipulator problems such as gravitational potential energy waste and poor operation characteristics, a hydraulic-electric hybrid semi-active driving system is proposed. Hydraulic cylinders with high power-weight ratio assist low power electro-mechanical actuators to drive the manipulator. Electro-mechanical actuators actively control the manipulator to improve the operation characteristics. Hydraulic cylinders are connected with the accumulator to form energy storage balance system, recycling the gravitational potential energy. According to different combination modes of electro-mechanical actuators and hydraulic cylinders, three different driving schemes are proposed. Taking the excavator boom as specific application object, detailed parameter matching design and simulation analysis of the three driving schemes are carried out. Compared with the load sensitive controlling system of three-chamber hydraulic cylinder, the hydraulic-electric hybrid semi-active driving system can further reduce energy consumption by 51%~56%. The boom velocity overshoot and fluctuation are small. The research provides a new direction for driving system of lifting mechanism, can realize green driving and has broad application prospects.

In order to find the ultimate energy saving boundary and clarify the energy saving mechanism of the independent metering system (IMS), static efficiency models and static energy consumption models of the conventional valve-controlled system (CVS) and the IMS are established, and then simplified to non-dimensional form by normalization method. Two kinds of working conditions which can be compared with the CVS are selected, that is, the same pump pressure source conditions and the same orifices area conditions. The comparison is made when the IMS is in the ultimate energy saving condition (the meter-out orifice is full-opened). Finally, the static efficiency and static energy consumption of two systems under different working conditions are analyzed by simulation. The comparison of efficiency distributions under all working conditions is obtained by the efficiency mapping. The results show that under the same pump source pressure, the IMS can improve the efficiency by about 5.7% and reduce the energy consumption by about 22.7% at most. Under the same orifices area, the IMS can improve the efficiency by about 19.4% and reduce the energy consumption by about 53% at most. The IMS can reduce the throttling loss of the orifices, and thus reduce the energy consumption of the CVS.

In order to reduce the impact of the folded control surface of the missile when it is unfolded under severe wind load condition in hypersonic flight, it's necessary to design an active damping gas actuator and develop the principle prototype. Based on the introduction of actuator structure and working principle, the main parts of the actuator are designed, and analyed by finite element method. Then it gives the method of wind load simulation on the control surface, and also provides the ground simulation loading system. The mathematical model and simulation model of the working process of the actuator are established, and the main technical parameters of the actuator are obtained through the simulation analysis by MATLAB/Simulink. Finally, ground simulation loading experiment shows that under the condition of downwind load, the piston rod of the actuator firstly accelerates, then decelerates, and finally moves to the final position at a smaller speed, so the actuator has a good load adaptive ability. The result of the experiment is almost consistent with the result of the simulation analysis, so the result can be a reference for subsequent engineering application.

As a common fault type of the electro-hydraulic directional valve, the internal leakage vibration signal has the characteristics of non-stationary and non-linear, and it is easy to be submerged and corrupted by other signals. For the feature, an empirical mode decomposition (EMD) and one-dimensional densely connected convolutional networks (DenseNet) method is proposed to diagnose the internal leakage in the Electro-hydraulic Directional Valve. Firstly, a series of intrinsic mode functions (IMF) are obtained by decomposing the vibration signals with EMD, and the IMF components and the original vibration signals are stacked in parallel successively. Then, the parallel stacked signals are used as the input of one-dimensional densely connected convolution network for feature extraction and fault classification. Finally, compared with DenseNet and the traditional one-dimensional convolution neural network, it can be concluded that this method can accurately and effectively diagnose the internal leakage fault in the Electro-hydraulic Directional Valve.

The development trend of miniaturization and integration puts higher requirements for the design of the hydraulic valve block. It is difficult and complicated to process the internal flow channel of the valve block with traditional technology. And the flow characteristics need to be improved. The new manufacturing process, additive manufacturing shows great advantages to inflow channel processing. Based on additive manufacturing the transition region of the flow channel is optimized design. Simulation was carried out by Fluent to analyze the characteristics of the flow channel connected by three methods: A linear transition, a circular transition, and a B-spline curve. It is found that the pressure loss of the B-spline curve transitional flow reduces more than 55% compared with the straight line transitional flow channel. The circular arc transitional flow channel is reduced by 28%~56% differently. The results provide a theoretical basis for the necessity of flow channel design based on additive manufacturing.

Taking a semi-submersible floating wind turbine platform as the object, the anchor chain and polyester fiber rope are connected in sections to form a tension mooring system, and the mathematical model of environmental load and the dynamic equations of the platform and mooring system under the environmental load are established. By means of Simulink lumped parameter calculation and AQWA numerical simulation, the platform's response characteristics under wind load step input and wave load sinusoidal input are compared and analyzed. The results show that the Simulink lumped model calculation results are similar with the AQWA numerical simulation results, which shows the rationality of the lumped parameter modeling method to a certain extent. The study found that under the action of wind step input, the platform mainly shows the response of the three degrees of freedom of swaying, heaving, and rolling. The swaying stability time is short, but the offset is relatively large. The stability time of rolling is long and basically consistent. Under the action of wave sine input, the platform also mainly shows the response of the three degrees. The amplitude of the swaying is also larger than that of the heaving. The reason for the larger swaying displacement and amplitude is that the design of the semi-submersible platform with tensioned mooring is adopted. Further restricting this degree of freedom is the next research direction of the optimal design of the platform and mooring system.

Medical waterjet separation technology is a fusion and optimization of modern technology and traditional surgery. Its research work has a construction significance for the development of precise surgery. This research summarized the development process and technical route of jet separation equipment, summarized the current status of jet technology and its research methods, analyzed the shortcomings of medical jet separation research, and proposed the goal of jet technology for clinical fine application.

In order to test work performance of floating drilling heave compensation device, a heave compensation test system is designed based on a similar theory, and it mainly includes a heave simulation system, a load simulation system and a heave compensation system. We use the software ADAMS and AMESim to establish a joint simulation model of the system, and the influence laws of initial volume of accumulator, inflation pressure and compensation cylinder area on system performance, and the corresponding relationship between heave compensation rate and system energy consumption are obtained. The results show that the system can achieve platform heave simulation, drilling load simulation, heave compensation and other test functions; it runs smoothly with good dynamic characteristics, and compensation effect is good.

Emulsion concentration has a significant impact on working performance and service life of hydraulic support, and we analyze existing detection methods of emulsion concentration. According to theoretical analysis of the relationship between bare fiber bending loss and refractive index, experiments are conducted to study the relationship between bare fiber bending loss and concentration of emulsion, and we put forward a method to determine the concentration of emulsion by detecting bare optical fiber bending loss. A device for detecting bending loss of bare fiber in emulsion is designed, and the relationship between bending loss of bare fiber and different concentrations of emulsion is studied experimentally. The experimental results show that the refractive index of emulsion can be measured by bare fiber bending loss method, and then the emulsion concentration can be calculated indirectly according to the corresponding relationship between the refractive index of emulsion and its concentration. Finally, an online measurement method of emulsion concentration based on the principle of fiber bending loss refraction is studied.

 Aiming at the problem of low efficiency for cylinder motion system, we propose an energy saving circuit. The idea of this circuit is to use four valves to form a full bridge, and achieve separate control of inlet and exhaust amounts controlled by the onoff time sequence of the four valves. The principle is to make full use of expansion energy to do work. The focus of this study is how to use nonlinear dynamic optimization to get onoff time sequence. a schematic diagram of the circuit is designed, and a corresponding test platform is set up. The sequence calculation is realized based on the sequence quadratic programming method with air consumption as the optimization objective. The correctness of sequence is verified by experiments.

A model reference robust adaptive control method is proposed for electro-hydraulic servo system with the consideration of model uncertainty and state constraints. The approximation model of electro-hydraulic servo system is first taken as the design object of model predictive controller (MPC). The constrained desired states, which are thought as the reference signals of the subsequent servo control design, will be generated in the design of MPC. In order to overcome various model uncertainties in the hydraulic system, a robust adaptive controller (RAC) is designed based on the backstepping method, and it achieves state constrained control of hydraulic systems with various model uncertainties. The asymptotic stability of closed-loop system is proved via the Lyapunov stability theory. The simulation results show that the proposed controller has strong robustness against various model uncertainties and achieves specific constraints of the specified states effectively, which verifies the effectiveness of the proposed control strategy.

This paper introduces structure and working principle of deflector plate jet servo valve. The jet amplifier is a crucial part of the valve, and the parameters of nozzle, receiving hole and guide outlet have a significant impact on the valve performance. When the nozzle and the receiving hole are rectangular, we change the length of the rectangular guide outlet. The valve pressure characteristic is analyzed by Fluent and a set of optimal parameters are obtained therefrom. We maintain the rectangular guide outlet area unchanged while we change the shape of the guide outlet into round and square. We analyze the pressure and the flow characteristics of the three guide outlets. Through modeling and simulation by MATLAB/Simulink, we verify the correctness of the Fluent analysis. The theory analysis and simulation results can provide references to structure design and optimization for the deflector plate jet servo valve.

The fault damage of various Lincoln pumps on mining equipments including mining machine, transportation machinery and drainage machinery is counted. The fault types are classified, and the fault reasons are analyzed. The costs of different maintenance schemes are compared. The functions of Lincoln pumps’ inflation testing instrument are analyzed, and the inflation testing instrument’s scheme is drawn up, and an inflation testing instrument is designed and manufactured. The inflation testing instrument’s actual effect indicates that the instrument will improve the maintenance quality and reduce the re-maintenance rate in the actual maintenance and repair process of the failed Lincoln pump.

In order to study the influence factors of the internal flow field of cotton picker fan, the internal flow field is simulated and analyzed by the Fluent software, and the internal velocity field and the suction negative pressure field of fan under different rotating speeds and flow conditions are analyzed. The calculation results show that with the increase of the rotating speed, the fan outlet speed and the maximum transportation speed increase, and the suction negative pressure of fan presents a trend of increasing continuously;with the increase of the flow rate, the outlet speed and the maximum transportation speed increase, and the minimum suction pressure decreases and the maximum value increases. This conclusion provides an effective reference for the improvement of the performance of cotton picker fan.

Aimed at the demand for deep-sea hydraulic manipulator joints, a rotary vane actuator is designed, in which a combined sealing structure is adopted according to different internal leakage. The rotary vane actuator leakage theoretical calculation model is established. The influence of sealing size and compression to the output torque and the internal leakage at different sealing pressures is analyzed by experiments. The effectiveness of the seal form and leakage theoretical calculation model is verified through the experiment, which supplies a theory base for the rotary vane actuator sealing structure design.

In order to improving the energy efficiency of construction machinery, a potential energy regeneration and utilization in hydraulic based on balance cylinder for the boom is proposed. The working principle of the balance system is analyzed. The mathematical model of the boom down has been established to analyze the influence on hydraulic natural frequency and damping ratio with energy recovery unit. To determine the reasonable range of key parameters, the simulation model is built in AMESim and used to analyze the influence on response characteristics and stability of the boom down speed based on different volume of chamber, gas pressure of accumulator and the volume of accumulator. A 1.5-ton hydraulic excavator is used to be the research object and a test platform to verify the energy efficiency of balance system is established based on it. The experimental results show that the energy recovery efficiency of the proposed energy regeneration and utilization system is 58.2% under standard working conditions, and the energy-saving efficiency of power system is 21%.

In order to suppress the surplus force disturbance of the electro-hydraulic hybrid testing system subject to acceleration vibration and force loading, the structure and working principle of the hybrid testing system are analyzed. Then, a dynamic model of the hybrid testing system is established, and its precision is verified by experimental results. Based on the dynamic model, the mechanism of the surplus force is analyzed and a feedforward decoupling controller is proposed. The performance of the proposed method is validated through experiments by an electro-hydraulic hybrid testing rig, and the experimental results demonstrate that the proposed algorithm can help the controller exhibit a better tracking accuracy than the conventional PI controller.

Those who suffer from the lumbar disc protrusion or waist injuries are of lower capacity, and then a novel auxiliary vest powered by pneumatic muscle is developed to help the patient. The whole scheme of the auxiliary vest is designed, and the pneumatic muscle and its accessories are used to act in the crotch and armpit, respectively. The pneumatic muscle elongates when it is inflated to reduce the stress on the waist. A new kind of bellows lining slip pipe pneumatic muscle with small radial dimension and radial stiffness is designed, and the isometric property of the pneumatic muscle is tested. The support capacity of the pneumatic auxiliary vest is analyzed. The test shows that the pneumatic auxiliary vest can provide a supporting force of 120 N at the air supply pressure of 0.2 MPa.

The exoskeleton is a kind of complex control system, which is controlled by human body and driven by mechanical structure. Furthermore, the man-machine interaction system is highly coupled. In order to realize the stable and reliable operation of the exoskeleton for a long time, it is necessary to solve the problems of the power unit. This study focuses on the research of the exoskeleton hydraulic power unit. There are four main parts: the working principle of the hydraulic system, the load of the exoskeleton robot, the gait analysis of the hydraulic power unit and a prototype experiment. Based on the experimental results, it shows that the negative severe lower extremity exoskeleton system adopts throttling speed regulation system, and it can meet the load 60 kg to complete the basic human lower limb movement, as it has a good human-machine coupling.

The machine performance of water hydraulic piston pumps whose piston pairs are made of 17-4PH/CFRPEEK and 1Cr17Ni2/CFRPEEK are studied. The sizes of the piston and cylinder sleeve are measured before and after tests. The tribological properties of two kinds of pairing materials are investigated. The results show that the efficiency of the pump by the use of 1Cr17Ni2/CFRPEEK as piston pairs is higher than that using 17-4PH/CFRPEEK. The abrasion resistance of 1Cr17Ni2 is better than that of 17-4PH when paired with CFRPEEK. In addition, the abrasion resistance of the CFRPEEK cylinder sleeves is better than that of the 1Cr17Ni2 or 17-4PH pistons. Generally, the 1Cr17Ni2/CFRPEEK shows better tribological performance than 17-4PH/CFRPEEK in water hydraulic piston pump.

The variable displacement pump, driven by engine which is used as the power source in traditional hydraulic excavator, causes high energy consumption and low efficiency in the part-load condition. To solve these problems, taking a 6 t hydraulic excavator as the research object, we propose a constant pump driven by servo motor flow matching control system. A simulation model of the servo motor is built by the software SimulationX, and the accuracy of the simulation model is validated by comparing the simulation with the test result of the servo motor response characteristic. Then, the boom co-simulation model include the mechanical structure and the electro-hydraulic system is built to analyze the operation and energy consumption characteristics under different control modes. The simulation results show that the energy consumption of the boom controlled by the flow matching control system can reduce by 13.6% compared with the load independent flow distribution (LUDV) system.

A novel PDMS electromagnetic microvalve which can be used in the pneumatic pressure control for lab-on-a-chip applications is presented. The structure and the working principle of the pneumatic electromagnetic microvalve are introduced. The mathematical models of the electromagnetic actuator are given, and the simulation models of the self-inductance coefficient, the coil current, the motion voltage, the mechanical motion, and the electromagnetic force are researched. The multi-physical field coupling mathematical models of the electromagnetic force, the elastic deformation force of the valve-membrane, the flow force of gas and liquid in pneumatic microchannels are developed. The deformable model of the valve-membrane, the outlet flow rate model of the PDMS electromagnetic microvalve, and the five sub models of the electromagnetic actuator are given by the software MATLAB/Simulink. The simulation of the dynamic response of the electromagnetic actuator and the dynamic flow rate of the PDMS electromagnetic microvalve is carried out. The predicted characteristics of the valve-spool driving force, the valve-spool response time, and the dynamic flow rate of the PDMS electromagnetic microvalve are given.

Focused on solving the problem that the helical pressure-regulated spring of the relief valve is easy to fail currently, a design method of the direct-actuated relief valve with permanent magnet spring is proposed. We discuss the mechanical performance of the permanent magnet spring by using the magnetic charge integration method and the finite element analysis by COMSOL. According to aerial servo system index requirements, we design the whole structure and critical parameters of the relief valve with permanent magnet spring.

By using the software AMESim to build the mathematical model of the grooved vane pump, we obtain the characteristics of the pouring flow when the pressure is dropped. The pressure pulsation rate is reduced to 0.05% by the method of the precompression and the pump’s outlet flow is compensated to the transition zone, and the phenomenon of the pressure drop when the low pressure oil is connected with the high pressure oil is basically eliminated. By the use of some devices to detect pressure and adjust the pressure amplitude, the pump becomes a closed-loop system that can be adaptively adjusted, and the pressure pulsation of the flow is always very small under varying loads.

The matching between the slipper the swash plate, the piston, the retainer plate important to ensure the normal operation of the piston pump. First of all, the theoretical analysis of the force on the slipper of the A4VG125 type piston pump is carried out and we apply SimulationX to establish one-dimensional hydraulic model and three-dimensional MBS model of the piston pump to simulate the pressure at the bottom of the piston. Then the hydraulic model is combined with the dynamic model established by ADAMS and ANSYS to complete the rigid-flexible coupling and fluid-solid coupling simulation model of the piston pump. The dynamic characteristics of the friction pair between the slipper and the swash plate, piston and retainer plate are analyzed by the simulation. The results show that, when the angle of the swash plate and the spindle speed are increased, the influences on the stress of the slipper and the working condition between slipper and piston pump are larger, and the force fluctuation of the spherical friction pair is more serious.

Continuum manipulator has many features, such as flexible movement, flexible joints, and can adapt to muti-obstacle environments. It will have great application value in the field of limited, narrow and dangerous space operations. The current continuum manipulator is mainly driven by motor, and its end bearing capacity is limited, generally less than 5 kg. In this study, a hydraulic-driven continuum manipulator is designed, and its joints are made of metal and connected by universal joints. The kinematic model is analyzed and the experimental system is built to verify the correctness of the model.

According to the nonlinear and time-varying characteristics of the valve controlled asymmetric cylinder, we establish the mathematical model of the system with the variable effective bulk modulus considering the influence of the oil compressibility. A fuzzy adaptive PID control method optimized by the particle swarm optimization (PSO) is proposed. Fuzzy logic inference is used to adaptively adjust the proportion, integral and differential coefficient of the PID controller, and the PSO is aimed to optimize the scaling factors and the quantization factors of the fuzzy controller. The combination of two methods ensures the adaptive control of the system with the best parameters. At the same time, AMESim and Simulink are used to simulate the dynamic response characteristics of the valve controlled cylinder model with different air contents under two control methods of the traditional PID and PSO_FPID. The results show that the PSO_FPID, which combines the high precise advantage of the PID controller and the flexible character of the fuzzy controller, can effectively restrain the effect of nonlinear dynamic compression properties of the oil and enables the system to maintain a good dynamic and static quality.

In this study, a U shaped silencing groove structure of the water hydraulic piston pump is studied. In order to decrease the fluid vibration, pressure and flow ripples of the water hydraulic piston pump, the pressure and flow characteristics of the pump with different silencing groove geometries are investigated through CFD simulation. And the optimal silencing groove structural parameter of the valve plate is selected to abtain the minimum pressure and flow ripple rates. The results based on the CFD simulation show that when the width, depth of the silencing groove, and the pre-compression angle of the valve plate are respectively are set as 2 mm, 0.8 mm and 11.8°, the pressure and flow ripple rates of the water hydraulic piston pump are the minimum. The vibration test of the water hydraulic piston pump with different silencing grooves is conducted, and the experimental results indicate that the optimal design of the silencing groove can effectively reduce the vibration on the port flange and the shell of the pump.

The performance of swash-plate type axial piston pump in the operating condition of low rotation rate is a significant factor, which influences the efficiency of the pump-controlled system driven by the servo motor. In this study, the mathematical model is checked to determine the optimized simulation model. According to a series of simulation, the flow rate characteristic of swash-plate type axial piston pump is studied in various rotation rates. Combined with the mathematical model, simulation model and experiment, the results of the fluctuated output pressure and flow rate characteristic in different rotation rates are obtained, which provide the basis and guidance to research the performances of the pump-controlled system driven by the servo motor.

We divide the human gait law of natural walk into 5 phases, and get the angles motion law of hip and knee in lower limb by human action capture test. Combined with the motion law of posture for the hip and knee, the knee motion of lower extremity exoskeleton is constructed and the characteristic of human-machine coordinated motion is analyzed theoretically to obtain the hydraulic cylinder dynamic load reference value with the pose servo control method. Using the servo valve to realize the servo-control for the displacement of the hydraulic cylinder, we design the feedback PID control law of the hydraulic cylinder displacement to carry out the force-assisted demanded in portable system under changed conditions of different weights, different poses. The overload-carrying test shows that the exoskeleton can bear more than 50 kg man-machine overloaded portable have a significant labor-saving effect for the tester.

Hydraulic cylinders are common execute components of the engineering machinery, and the internal leakage is a common fault mode of hydraulic cylinder that can affect the efficiency and safety of the machinery, so the in-time detection of internal leakage can assure the normal work of the hydraulic cylinder. Based on the wavelet decomposition, the signal features of the inlet pressure of hydraulic cylinder could be extracted and the internal leakage could be intelligently detected through a BP neural network classifier. The test results show that the accuracy of the classification is acceptable. Consequently, the efficiency of the fault diagnosis of the internal leakage of hydraulic cylinder is improved and this study provides a basement of the intelligent condition based monitoring for hydraulic cylinder.

Rated flow and frequency response are two important indexes of the high speed on/off valve but the biggest internal contradiction is also between them. To the high speed on/off valve product, its flow characteristics are basically determined when assembled. However, its frequency response characteristics can be improved through an optimization of the subsequent control algorithm, and the internal contradiction of flow and frequency response can be relieved. In this study, a high speed solenoid simulation model is built, and based on this model, the dynamic performance of the high speed on/off valve with different control strategies is analyzed when the flow characteristics remains stable. At the same time, the advantages of three voltages control strategy are verified by simulation.

Target object can achieve low detectivity when its infrared radiation characteristics are reduced or changed by infrared radiation stealth technology. Water mist, based on its characteristics of the particles' absorption, dispersion and overlay of water film, is an effective way to weaken the infrared radiation intensity. Water mist, which has special phase transition and flowing characteristics of water film, has gradually been applied in the project. Effects caused by water film thickness, velocity and droplet diameter on infrared radiation intensity of the tested model have been studies. Based on the theory of the infrared radiation, Mie scattering and atomizing nozzle, the infrared stealth model is built to determine its characteristic parameters by ANSYS and MATLAB. In addition, designed nozzles are applied in certain tested models to further validate the simulation results. Finally, the experimental data of the water mist are further analyzed and summarized to obtain better infrared radiation parameters.

In this study, a mathematic model of double nozzle flapper servo valve is introduced. This model includes three parts: motor toque, armature baffle components and slide valve in the double nozzle flapper servo valve. For motor toque, the facts, including magnetic flux leakage and reluctance of permanent magnets, reluctance of magnetic components and working air gaps, are considered. Two DOFs (translation and rotation) of the armature baffle components are considered while an ordinary model is adopted for slide valves. Also, the impacts that the spring tube on the synergic movement position system and amplitude swing system are discussed by using and comparing with two different AMESim models.

A novel method for early fault recognition of rolling bearing is proposed. The method integrates the variational mode decomposition (VMD) denoising method and the kernel fuzzy C-means (KFCM) clustering method. Firstly, a new method for determining the present scale K of VMD is proposed by the leaked energy and cross-correlation coefficient function synthetically. Shortage of the traditional empirical selection method for K in VMD is overcome. Secondly, the faulty vibration signal is decomposed by VMD to obtain the K band-limited intrinsic mode function (BIMF) components. And in order to find BIMF including noise, the principle is utilized that the normalized energy concentration ratio of auto-correlation coefficient function is greater than 0.9. Then, the BIMF including noise are eliminated and the residual BIMF components are reconstructed to realize denoising. Finally, the root mean square value and the normalized energy of every sample are calculated. The two-dimensional characteristic vector sample sets are obtained, and they are put into KFCM clustering algorithm for fault diagnosis. Analysis of measured fault data of bearings show that the proposed method can realize the early fault diagnosis of rolling bearing effectively when compared with the empirical mode decomposition (EMD) method.

The control method of the water hydraulic proportional valve is studied. The proportional valve is designed with two-stage structure, in which the spool displacement of the valve in the second stage is controlled by the valves in the pilot stage consisting of four poppet valves. Based on structure characteristics of the proportional valve, the proportional valve is simplified into the physical model of double rod symmetric cylinder which is controlled by four independent variable orifices. By adding constraints and through referring to the model of symmetrical cylinder which is controlled by symmetric four-way slide valve, the transfer function of this simplified model is derived. Then, a self-tuning fuzzy-PID control algorithm is designed to control the proportional valve. Two parameters are chosen as the input of the fuzzy controller, which includes the deviation between expected value and measured value of the proportional valve opening, as well as the change rate. The three parameters of the PID controller are adjusted dynamically through calculating the increment of the parameters, which are exported by the fuzzy controller. Finally, the results of the MATLAB/Simulink simulation show that the self-tuning fuzzy-PID control algorithm has more obvious advantages compared with PID control algorithm.

Taking the end of the “smooth” rounded salvage as an example, we put forward the structure of the sinking ship lifting test platform, and build up a platform for simulating the sinking and heave compensation of the wreck. In view of the two-degree-of-freedom heave compensation platform, the kinematic inverse solution is built and the Simulink model based on kinematics control is built. The simulation of the wave motion is realized by the two-degree-of-freedom platform based on the valve-cylinder servo control system, and the model of the motion control and heave compensation control system is built up. The motion control ability and the dynamic response ability of the two-degree-of-freedom platform heave compensation control system are verified by ADAMS and MATLAB. The compensation characteristics of the system are proved by comparison of the displacement of the heave platform before and after compensation.

A hydraulic system based on vibration energy converter is proposed in this study for the vibration of the main engine with the consideration of the construction environment features. The structure and the working principle of the vibration energy absorption converter are introduced,and the simulation software AMESim is used to establish the model of the converter. The influences of the structure parameters and the working conditions on the performance of the vibration energy absorption converter are analyzed based upon the simulation results. The analysis indicates that the vibration energy converter presented in this study can achieve the expected function. Meanwhile, under the structure, the shaft speed of the hydraulic motor increases first, and then decreases with the frequency of the piston, and the shaft speed increases with the moving amplitude of the piston is not obvious, and the angular acceleration of the shaft decreases with the volume of the accumulator. Moreover, the vibration energy converter will be at fault as the spring rate of check valve is not suitable.