To improve the linearisation of the variable flow-regulate system under the open-loop control, a proportional solenoid valve with high-linearity performance was developed to meet that requirement of the high-precision and open-loop control. The design of the proportional solenoid valve evolves the optimisation of a magnetic circuit structure, the construction of a balanced pressure structure and the compensation of a feedforward control device. As for the solenoid, it is very challenging to meet the requirement of 95% linearity. A feedforward control device with the Bouc–Wen model and a quadratic inverse function model is a good solution to address the hysteresis problem and achieve better performance. The optimisation of a simple magnetic circuit with low sensitivity to the moving armature and a balance chamber for removing the pressure difference are both preconditions to make the compensation. The feedforward control device is the next step to eliminate the hysteresis problem and non-linear characteristics of the solenoid by solving model coefficients measured in the test. After the improvement in these aspects, the proportional solenoid valve can meet the demand of digital proportional flow control with >98% linearity and excellent repeatability, through the validation of both no-load and high-load performance tests.

In the helicopter hover refuelling system, the emergency breakaway device is an important component to ensure the safety of the helicopter. It requires automatic disconnection and sealing of the pipeline under the tension of 1700–2000 N. The claw type emergency breakaway device was designed, the three-dimensional model is established for dynamic analysis, and the optimal parameters of the breakaway device are obtained by orthogonal experiment. Then, the calculation equation of the braking force is obtained through analysis. The sealing structure of the emergency breakaway device adopts a pair of poppet valves. In order to verify the reliability of the braking force and the seal, the emergency breakaway device is subjected to a water-passing test. The results show that the emergency breakaway device is separated with the required breaking force and the leakage amount is zero after the breakaway.

To decrease the injury caused by an accidental collision between the hydraulic manipulator and human, a hydraulic rotating angle self-servo compliant robot driver joint is designed. Based on this joint, a variable stiffness passive servo-hydraulic rotary joint is improved. The passive follow-up characteristics of the improved servo-hydraulic rotary joint enable it to enter the low stiffness mode by itself when it encounters collisions beyond the force limit. Combining this characteristic, the research method of the hydraulic mechanical arm flexible configuration is proposed. Firstly, the joint motion mode is defined by the Euler angle, and a variety of configurations conforming to the motion characteristics of the manipulator are determined. Then, the virtual prototype and collision environment are built, and the dynamic characteristics of the end effector of the arm under high and low stiffness are measured. The results show that the flexible configurations with passive follow-up characteristics can significantly suppress the collision force. Finally, the visual method is employed to solve, draw, and compare the workspace of the selected compliant configuration, to obtain the optimal compliant configuration with both flexibility and motion, which provides theoretical guidance for the subsequent design of the compliant manipulator.

This study proposes a non-invasive method for estimating the pulsating flow and pressure difference, which uses the blood pump estimation model based on a multi-layer perceptron to calculate the flow and pressure difference under pulsating conditions. The model takes 11 parameters such as the rotational speed, power, and pulsation waveform of the blood pump as the input and uses the pressure difference and flow as the output. The experimental results of 119,590 sample data show that the flow error of the training set of the blood pump estimation model is 0.14 l/min and the pressure difference error is 7.50 mmHg; the flow error of the test set is 0.14 l/min and the pressure difference error is 7.50 mmHg. Compared with the traditional flow and pressure prediction method, this method has higher precision, which will provide a certain technical accumulation for accurately estimating the flow and pressure difference of the blood pump in the pulsating conditions.

Flow and pressure ripples of axial piston machines have received sustained attentions by researcher in flow power domain. Traditionally, almost all the axial piston pumps have been designed with odd number of pistons. This study presents a novel study focusing on the actual flow and pressure pulsations of even number piston pump. A fluid dynamic model based on lumped parameter approach is presented to predict the flow and pressure performance of axial piston pumps. Particularly, the cylinder and valve plate are re-designed to fit the ten-piston pump based on a commercial pump. Both the simulation and test results show that the pressure pulsation rate of ten-piston pump is actually few percent bigger than that of nine-piston pump. The relative difference is much smaller than what has been expected by the theoretical flow calculation. Therefore, the design of axial piston machines with even number of pistons may be feasible in some circumstances.

In order to fully predict the performance of variable displacement vane oil pump (VDVP) during concept design phase， one-dimensional simulation software AMESim is used to model the centralised parameters of VDVP. Several important performance indexes of VDVP are predicted, including the flow, pressure, torque and initial variable point, it is proved by the bench test that the simulation results have a good correlation with the test results. In addition, the effect of leakage on volumetric efficiency is studied, external leakage is smaller than internal leakage, and the higher the temperature, the larger the leakage. The force characteristics of VDVP are studied. Under extreme conditions, the maximum pressure of the internal chamber is about 15.9 bar, and the maximum forces of the stator and rotor are 1920 and 1653 N, respectively. The effect of temperature on the frictional power is studied. Under low-temperature conditions, the viscous frictional power is much greater than the dry frictional power, while the high temperature is the opposite.

The kidney-shaped holes variable four-port hydraulic transformer of inlet and outlet equal flow is proposed, such as the theory, the flow of port A and port B is the same and equivalent to a hydraulic motor. The flow of ports O and T is the same, and the equivalent of a hydraulic pump. The A and B kidney-shaped holes of the valve plate are the same. The O and T kidney-shaped holes are the same. The transformer ratio can be changed by adjusting the control angle of the valve plate. The mathematic models of displacement, angular torque, and pressure transformation ratio about the four-port hydraulic transformer are built. The derivative relationship between the pressure transformation ratio and flow of port B, recycling pressure difference, and viscosity is deduced, respectively. Based on it, the influence characteristics of the three factors on the pressure transformation ratio are obtained. The result of theoretical analysis and simulation shows that the increment in the flow of load circuits leads to a decrease in the pressure transformation ratio, while the decrease in viscosity and the increment in recycling pressure difference lead to an increase in the pressure transformation ratio.

At present, there exists a problem that the frequency and phase are not synchronised in the blood pump pulsation flow control. After analysing the time sequence of the blood pump-heart coupling model, this study has designed a synchronous control strategy based on heart rate prediction and delay control. By predicting the next moment of cardiac action, the change in blood pump speed was delayed to match the frequency and phase of the cardiopulmonary system. The new prediction method increases the linear weight and state variables, and solves the problem that the traditional method has poor real-time performance, and still has better detection accuracy. Through the synchronous tracking experiments of the blood pump, the feasibility of the method has been proved, and the technical accumulation of the fully synchronised blood pump pulsation flow control method could be provided in the future.

A safety design method of a civil aircraft cargo door actuation system has been listed in this study in order to fulfil the requirements of airworthiness throughout the product's life circle, in which a safety design process has been illustrated to show the entire process which will have an impact on the function design. A safety analysis method of fault tree analysis has been chosen to realise the purpose, which is based on the fault modes provided from failure modes and effects analysis and the system reliability prediction results. A design refinement has been made according to the analysis results in order to realise a high safety system.

Smoothed particle hydrodynamics (SPH) is a meshfree, Lagrangian, particle method, which combines the advantages of Euler and Lagrangian method and has special advantages in simulating violent non-linear fluid–structure interaction problems. In this study, an improved SPH method is used to simulate four fluid–structure interaction cases. Firstly, the violent flow in the mould filling process is simulated to validate that the SPH model can obtain accurate flow patterns with any complex solid boundaries. Secondly, the dam-break flow against a vertical wall is simulated, and the pressure curves are compared with the experiment. Then liquid sloshing problems under different external excitations are simulated, and the complex coupling characteristics can be captured. Finally, the interactions between fluid and floating bodies are researched. The obtained numerical results show good agreement with the results from other sources, and clearly demonstrate the effectiveness of the presented SPH method in modelling fluid–structure interaction problems.

Based on the analysis of the structure and operation mode of low-floor urban trams, the structure, principle, components and technical parameters of the anti-kink hydraulic system which specially set up were described, and the application characteristics of the hydraulic system technology were pointed out.

Magnetorheological (MR) shimmy damper has a good application prospect in aircraft landing gear shimmy control as a semi-active vibration control device; however, its non-linear and hysteretic characteristics bring difficulties to the control and restrict performance. It is necessary to develop a dynamic model of the damper that can effectively show these characteristics. This study is based on the experimental data of the damping force characteristics of MR shimmy damper with different control currents. Bouc–Wen model, apply to describe non-linear and hysteretic characteristics, was selected to establish the dynamic model of damping force, displacement and velocity. This study proposed an improved simulated annealing (SA) algorithm, which can improve the efficiency of identification, to identify the parameters of the model. Comparing with the original algorithm, the improved SA algorithm has the same solution quality and better performance in computational efficiency. The relationships between the identified parameters and the control current were obtained by curve fitting, and the experimental data with different amplitudes and frequencies are used to verify the result. It is shown that the established model can accurately show the dynamic characteristics of the damper under different excitation.

In this study, the structural composition and working principle of the single wedge two-way backstop are analysed, and the factors affecting the self-locking of the single wedge two-way backstop are explored. Two wedge shapes are established, the contact stress between the wedge and the outer casing is calculated by ANSYS and compared with the stress value calculated by Hertz theory, to verify the applicability of the finite element method.

The high-speed train transmission system is a complex electromechanical coupling system. In this study, the torsional vibration of a train transmission system was studied. The centralised mass model of the mechanical structure of the coupling system was established. The natural vibration characteristics of the mechanical mechanism system were analysed. The results show that the natural vibration frequency of the universal shaft was 4.08 Hz, the natural vibration frequency of the pinion was 7.24 Hz, the natural vibration frequency of the big gear was 35.6 Hz, and the natural vibration frequency of the wheelset was 107.48 Hz. The traction motor model was built, and by considering the electromechanical coupling of the system, a torsional vibration suppression strategy for harmonic components in the motor is proposed. The effectiveness of the suppression strategy was verified by MATLAB/Simulink model simulation.

To study the quality control technology and process specifications of solid–liquid two-phase abrasive flow research and development, the fourth-order variable diameter pipe is taken as the research object, and then the quality control method of abrasive flow polishing variable diameter pipe is established. Through the analysis of the abrasive flow of the fourth-order variable-diameter pipe, it is known that the surface texture of the variable-diameter pipe becomes smoother and denser after the grinding flow, and the surface roughness Ra of the variable-diameter pipe is reduced from the original 1.469 μm to after polishing 0.295 μm, the surface roughness is improved, and the ideal polishing quality is obtained. Under the experimental conditions, the optimal process parameters of solid–liquid two-phase abrasive flow were obtained, and the regression model of surface roughness and process parameters was established, which provided technology for engineering application of solid–liquid two-phase abrasive flow.

By exploring the effects of energy and velocity under different inlet speeds and abrasive concentrations, different inlet boundary conditions were selected for numerical analysis, and the intrinsic properties of the solid–liquid two-phase abrasive flow research and development calibre pipes were explored. The influence of law and process characteristics of solid–liquid two-phase abrasive flow is discussed. The fourth-order variable diameter pipe is taken as the research object. It is concluded that the inlet velocity is increased, the total energy and kinetic energy of the abrasive grains are also increased, and the total energy and kinetic energy are increased. The more intensely the abrasive grains collide with the workpiece wall, the more favourable is the effect of the abrasive flow on the wall surface finishing, and the increase of the abrasive concentration. The number of collisions of the disordered abrasive grains on the wall surface is increased, which is more conducive to the wall surface. The finishing process provides theoretical reference and technical support for the engineering application of solid–liquid two-phase abrasive flow.

The model of rotor vector (RV) reducer was established by 3D software, and was imported into ANSYS Workbench for transient dynamic analysis. The stress distribution diagram and total deformation diagram of the gear tooth surface during the meshing process of the cycloidal wheel and the pin wheel were obtained, and the stress distribution law of the cycloidal wheel in the process was also obtained. Comparing the calculation results of Hertz formula with the results of finite-element analysis showed that the deviation are smaller and within the allowable range, which provides the theoretical reference for the optimisation of the cycloidal wheel.

In this study, the authors used a steady jet from a slit nozzle to control the bi-stable aerodynamics of a simple vehicle model under crosswind conditions. In general, the aerodynamic coefficients of an automobile change continuously with variations in the relative wind direction (i.e. yaw angle). However, some vehicles show a significant change in their aerodynamics at a certain yaw angle because their wake flow structure changes at that yaw angle. Furthermore, around that critical yaw angle, their aerodynamics sometimes show bi-stability in which both the wake structures before and after the change are stable. The investigated model is the famous simplified model in vehicle aerodynamic research known as the Ahmed model. Its slant angle was set at 32° as a configuration that causes bi-stability at a specific yaw angle range larger than 6°. The active aerodynamic control method was demonstrated in both the model scale wind tunnel test and computational fluid dynamics analysis. The slit jet with 18% of the main flow velocity successfully changed the wake flow structure. This showed that it is possible to improve the aerodynamic characteristics.

Because of the special forging material and complex pipe structure of the main pipe of the AP1000 nuclear power plant, a single general equipment can not meet the requirements of machining the inner hole of the bending section. At present, most of them adopt the method of approaching theoretical dimension by manual grinding, which makes the labor intensity of workers large, the work cycle is long, and it is difficult to ensure the machining accuracy of the workpiece. In view of the practical difficulties in processing the elbow inner hole of nuclear power main pipeline, the copying processing equipment is designed. The fixed circular arc guide rail is used in the equipment. The arc curvature of the guide rail is the same as that of the workpiece. The boring cutter head moves axially along the fixed circular arc curvature guide rail for copying boring. After testing, it fully meets the requirements of the shape, position and size accuracy of the inner hole in the bending section of the nuclear power main pipeline. The method is efficient, accurate and innovative, and provides reference for similar product processing schemes.

Wheeled skid-steered vehicles have the advantages of compact structure, small steering radius and wide application. However, poor steering performance is an important limitation restricting the development of wheeled skid-steered vehicles. A kinematic model for analysing the relationship between wheels’ rotation speed and the motion state of the vehicles’ mass centre based on Newton's second law was established, then the correctness of the kinematic model was verified by comparing the calculation results with simulation results. The key design perimeters affecting the steering performance were analysed by a control-variable method based on the established kinematic model. The results indicate that the established kinematic model can evaluate the steering performance of skid-steered vehicles correctly and can provide a reference for optimising the design of the vehicles.

Based on the electromagnetic induction Hall zero position sensor, a multi-stage reducer motor structure system with a brush DC motor is designed using an aviation fuel on–off valve. The output shaft of the motor structure can respond to commands, rotate double directions, and lock the brake shaft after reaching the designated position. After that, the current position and on/off situation of pipeline fuel can be derived accurately. The system has the advantages of light weight, small volume, fast response, high precision, high reliability, and integration.

An integrated Matlab model comprising of an electro-mechanical actuator (EMA) model, load model and state model has been constructed to investigate the cargo door actuator motion control, operation and working states, of which, a Simulink® servomotor system model is adopted to mimic the EMA actuator, a SimMechanics® model is used to compute the actuator's load, a Stateflow® state transition model is employed to simulate the working process. The results indicated that the motion is well controlled, generated load force is valid, working states and their transition logics are reasonable. The simulation verified the effectiveness and easiness of the integrated modelling method.

A certain type of proportional valve has been optimised in design by adding a damping hole in its structure, which solves the problem of pressure rise in the fuel chamber due to gap leakage when closing. An integrated circuit electromagnetic model is used to mesh the model. Based on FLUENT software, the flow characteristics of the proportional valve at different valve opening have been analysed to get the curve of turbulent kinetic energy, pressure, and flow in internal field changing with different valve opening. The results show that the proportional valve with a damping hole has faster response speed and less pressure loss at the inlet and outlet of the valve. The data and conclusion obtained in this study are very important for the performance improvement of the proportional valve.

The accumulator is a crucial component of the hydraulic power for servomechanisms of the launch vehicle, which has a significant effect on the performance and the mass power. Traditional design methods are mostly based on empirical formulas, which do not meet the requirements of the fine design of aerospace products. The physical model, the mathematical model of the accumulator and joint simulation model of the energy and the control loop are established, and parameters satisfying the extreme flight operation profiles are obtained, including the discharge volume, charge volume and charge pressure. The flight data of third-stage servomechanisms of the Long March 3 series Launch Vehicle were analysed, which is consistent with the simulation data, indicating that the accumulator has exerted the maximum capability in the extreme flight condition, and the maximum mass power has been realised.

In order to study the fluid flow characteristics of the key components in the hydraulic excited rotary valve, then determine the area of vortex and negative pressure to find the weak link in the structure and analyse the performance of the valve. Simulate the flow field in the rotary valve by Fluent fluid analysis software and set different opening degrees under the same boundary conditions. Studies showed that the velocity at the exit junction of the fluid in the rotary valve and the vortex degree of pressure are large at the oil groove. When the opening degree is small, the negative pressure is large, the vortex is obvious. When the opening becomes large, the negative pressure and vortex are improved. The research provides a theoretical basis for the optimisation and improvement of the rotary valve.

This study designs one kind of hydraulic auto-brake-valve calculates its driving force and velocity, simulates its braking force and stability, in order to accomplish auto brake in the landing condition and keep braking in cruising condition of the unmanned aerial vehicle. The auto-brake-valve uses a servo motor to drive lead screw and nut. The output press of the auto-brake-valve is changed by the variation of rotate speed and direction of servo motor, that can be completed the control of the brake device.

In order to solve the problems of low production efficiency, poor quality of blanks, high labour intensity and inability to meet the market demand with the manual gypsum mould, a novel design of the gypsum mould to be applied into the automatic production of the planks was developed for ceramic handicrafts. This mould inherits the advantages of the manual mould with tenon–mortise connection and adopts six-piece combination. According to the spherical radial movement, the new mould opens and closes, mostly avoiding movement interference and significantly improving service life. The connection technique of ‘six-point positioning principle’ was proposed and adopted to embed the connection device of four side die pieces with manipulator, so as to realise the strength of gypsum die pieces and effectively connect with the manipulator. Based on the group technique, the standard eigenvector and norm for the grouping of geometric elements of target blanks were proposed to realise the grouping of many different kinds of blanks into a few number of groups with all the blanks. Within a group, the gypsum mould keeps the external geometric features and tenon–mortise connection unchanged, while the working cavity of different blanks only alters, for the flexibility of gypsum mould. Thus, the universality of the mould is gained, and the design and manufacturing efficiency is greatly improved, with the considerable reduction of the cost, and the digitisation of design, manufacturing and management processes is realised. The gypsum mould provides a new technological method and technical guarantee for changing the labour-intensive production mode of ceramic handicraft blank cast and forming, realising the intellectualisation and automation of the main production link of ceramic handicraft blank cast and efficiency automatic and intellectualised production of ceramic handicraft blank with high identity.

Cone pyrolysis liquefaction reactor is the key core device of biomass energy production equipment. The study of the dynamics of the cone is of great significance to the bioenergy conversion technology. Proper control of the movement time of the heat carrier in the cone can prevent it. Biomass superheated carbonisation can increase the ratio of gas and liquid formation. It is a difficult and key technology in the design of the cone pyrolysis liquefaction reactor. The kinetic differential equation of the relative motion of heat carrier particles can be obtained by kinetic analysis and calculation. It can play a key role in the in-depth study of the structural size design of the cone and the optimisation of the structural size parameters. This study conducts a dynamic simulation of the physical simplification model of biomass energy production equipment. The computer simulation software was used to simulate the running process of the simplified cone mechanism model. A reasonable physical prototype that meets the process parameters is designed. In view of the above complex dynamic phenomena, it is necessary to comprehensively analyse various methods of dynamics, and use appropriate numerical analysis and computer-aided design methods to carry out system equipment research and design.

Biomass fuel production has a variety of methods, and the use of biomass cracking to produce biofuels is an advanced technology used in many countries. In the control of the biofuel production process, how to get the motion law of the heat carrier in the cone relative to the cone becomes a problem that must be solved. This study uses the basic theory of dynamics and computer simulation calculation function to carry out dynamic analysis of each of the above contents, and analyses the response problem of comprehensive factors, and obtains the simulation results in accordance with the experimental results. This analysis provides a detailed design rationale for the optimal design of biomass cone pyrolysis equipment.

Grape covering machine as key equipment casing mechanised grape winter is drawing more and more attention. To analyse the performance of the grape covering machine, the soil cutting process of opening soil knife with a 3PF-240 grape covering machine is studied. Based on the finite-element analysis software ABAQUS, the three-dimensional dynamic contact non-linear finite-element analysis of the soil cutting process was carried out, and the cutting force curve of the cutting tool in the case of the tool was obtained. To verify the correctness of the simulation results, the grounding work of the prototype was carried out. The experimental results show that the established mechanical model of the opening soil knife is correct, which provides a theoretical basis for the further development and optimisation design of the grape cover.