The stretching ratio is a crucial factor affecting the lubrication state of reciprocating seals. Traditional axisymmetric models oversimplify the problem by neglecting the influence of circumferential stretching, leading to insufficient accuracy in handling nonlinear issues. Additionally, the microscopic morphology of the sealing surface affects the fluid flow at the sealing interface. Therefore, a lubrication model incorporating the microscopic morphology of O-rings along with a three-dimensional simulation model is proposed. The study investigates the distribution patterns of macroscopic contact stress and oil film thickness under different stretching ratios. The results indicate that as the stretch ratio increases, the maximum contact pressure during both extension and retraction gradually decreases, while the oil film thickness increases. The simulation results closely match the experimental data, with the calculated friction force deviating from the experimental results by approximately 12.65%.

The independent control of power sources and power transmission components in positive control flow excavator transmission systems, and the unified control strategy for hydraulic systems under all operating conditions, lead to poor coordination between vehicle powertrain system and suboptimal fuel economy utilization. To improve overall fuel efficiency, this study focuses on 90° truck loading operations by analyzing the entire operational process. Based on hydraulic pilot pressure signals, the operational cycle is divided into four distinct phases. By examining the performance of the engine and hydraulic pump, this study analyzes load variation characteristics and responsiveness requirements across different phases. At the same time, based on the driver's operation, this study analyzes the evaluation indicators that affect the fuel economy of excavator vehicles, clarifies the influencing factors of fuel economy, and proposes a vehicle control strategy for excavator 90° loading operation conditions.Compare with the original vehicle test data, the results show that adopting a collaborative control strategy can make the engine and hydraulic pump tend to work in the optimal state. Compare to the pre optimized gears, the fuel efficiency can be improved by 10.2% to 12.1% while maintaining comparable efficiency.

The dynamic pressure signals of hydraulic systems have the characteristics of nonlinearity, multi-source coupling, and sensitivity to operating conditions. This results in high signal complexity and low feature discernibility, rendering traditional diagnostic methods ineffective. A deep learning diagnostic framework based on multi-sensor collaborative perception is proposed to address these issues. Multiple heterogeneous sensor signals are mapped into a multi-channel input tensor through spatial topology mapping, which preserves independent sensor features while achieving joint representation of multimodal information. A parallel convolutional architecture extracts spatiotemporal features from each channel, and an effective channel attention mechanism enhances fault-sensitive information, optimizing cross-modal features for precise classification. Experimental results show that the proposed method achieves over 95% accuracy in diagnosis of hydraulic pump leakage fault on the UCI standard hydraulic dataset. By introducing transfer learning theory, the pre trained model trained on the UCI standard hydraulic dataset is transferred to the forklift lifting hydraulic system, and the model still maintains an accuracy of 97.65%. These results confirm the model's strong generalization ability across different scenarios and provide an effective solution for fault diagnosis in complex hydraulic systems.

To reduce the overall energy consumption of hydraulic excavators and improve the energy utilization efficiency of the hydraulic system, this study proposes an energy recovery and reuse system for the potential energy of the excavator's boom, utilizing a hydraulic winch and an accumulator. The system recovers gravitational potential energy during boom descent and reuses it to assist in boom lifting, thereby reducing the working pressure of the hydraulic system and decreasing fuel consumption. First, the working principle of the system is elaborated in detail, and a mathematical model of the energy-saving device is established. Next, the system is modeled and simulated using AMESim software. The simulation results demonstrate that the system effectively recovers the gravitational potential energy of the descending boom and assists in boom lifting, achieving an energy-saving efficiency of approximately 55.6%. Finally, an experimental bench is constructed to validate the feasibility and effectiveness of the proposed energy-saving device.

Most domestic diesel generator sets in China use mechanical-hydraulic governors for throttle control. Analyzing the operating principles and characteristics of this mature and reliable governor provides critical reference for domestic independent design initiatives. This study constructs component models such as centrifugal flyweight of the governor in AMESim, and develops a diesel generator set dynamical model in Simulink based on the engine load, throttle opening and speed characteristics. Through AMESim/Simulink co-simulation, the study investigates the dynamic behavior of hydraulic buffer compensation in closed-loop speed regulation and its impact on performance. The results indicate that adding hydraulic buffer compensation effectively reduces both the settling time and speed oscillations of diesel generator sets under diesel generators load variations. This design concept not only applies to mechanical-hydraulic governors but also provides critical insights for the autonomous development of digital electronic governors.

The vibration and noise of the bent-axis axial piston motor is investigated by a combination of test and simulation. Firstly, the vibration and noise excitation sources of piston motor are investigated and analyzed according to its structural composition and working principle. Secondly, the modal analysis and harmonic response analysis and calculations are carried out by using the simulation software to get the intrinsic frequency of the piston motor and the frequency curves of vibration-related parameters, and the accuracy of the simulation model and test method is verified with vibration tests.Finally, the noise radiation analysis and simulation of the piston motor is carried out by acoustic-vibration coupling method, and the reasonableness of the simulation results is verified with noise test. It is concluded that the peak frequencies of vibration and noise tests are around 700 Hz, which is highly consistent with the theoretical value of excitation frequency 700 Hz, and also close to the first-order intrinsic frequency 704 Hz of the piston motor shell. It proves that the piston motor system is in resonance at this frequency, and proposes optimization directions for vibration reduction and noise reduction of piston motor structure. This study reveals the main mechanism of the vibration noise of the piston motor and provides a basis for its vibration reduction and noise reduction.

Insufficient control precision is caused by strong nonlinearity in vacuum butterfly valve pressure control systems. A dual-mode switching strategy fusing Active Disturbance Rejection Control (ADRC) and PID control is proposed. The controller utilizes an extended state observer to uniformly estimate and compensate for aggregated disturbances including gas temperature drift, sealing friction, and gas source fluctuations. A pressure error threshold triggering mechanism is designed to activate ADRC exclusively during dynamic processes for rapid overshoot suppression, while automatically switching to lightweight PID control during steady-state operation to maintain precision. Compared with conventional PID control, settling time of proposed method is significantly shortened and overshoot substantially reduced. Compared with single ADRC control, steady-state error is effectively minimized. Under flow disturbances, pressure recovery time is 67% faster than that of PID control, with a steady-state error below 25 Pa. This approach significantly enhances system response speed, precision, and robustness, fully leveraging the cost advantage of butterfly valves. And it provides a high-performance, low-cost vacuum pressure control solution for semiconductor, aerospace, and related fields.

Aimed at the problem that it is difficult to levelling the lifting heavy-duty automatic guided vehicle and there exists the “floating leg” issue during leveling, a four-point support heavy-duty automatic guided vehicle hydraulic leveling system is designed and a position compensation mathematical model of hydraulic leveling system is established. The model consists of a highest-point chasing leveling mathematical model and a position compensation mathematical model. The highest-point chasing leveling model is used to execute the leveling process, and the position compensation mathematical model is used to solve the “floating leg” issue in the process. Based on the designed model, the conventional fuzzy PID control strategy is improved, and an enhanced fuzzy PID controller considering floating legs is proposed. A Simulink-AMESim co-simulation platform is built to validate the proposed strategy. The results show that compared with the conventional fuzzy PID method, the improved controller reduces the maximum tracking error of the lowest-point hydraulic cylinder by 86.59%, effectively alleviating the “floating leg” phenomenon.

To address the needs of deep-sea hydraulic systems under complex multi-actuator working conditions, this study investigates hydraulic power unit (HPU) technologies and proposes an externally mounted, integrated outboard HPU configuration. The design integrates a compensation oil tank, motor, and hydraulic pump into a unified structure which provides many capabilities like providing flow, pressure and power. To adapt to diverse hydraulic drive requirements. The HPU delivers a rated pressure of 21 MPa and a maximum flow rate of 90 L/min, meeting the demands for high-pressure and high-flow hydraulic power in deep-sea operations. This study conducts a series of performance validation tests, including land-based functional tests and pressure chamber tests. The test results demonstrate that the integrated deep-sea HPU operates stably under high-pressure conditions, with all performance indicators meeting design requirements. This provides an efficient and reliable solution for the hydraulic system of deep-sea manned platforms.

Magnetic fluid seals with large diameter are prone to deformation in the environment with a wide temperature range, resulting in a decrease of its maximum working pressure, which means a decline in its pressure resistance performance. In this research, a pressure resistance formula for magnetic fluid seals with the consideration of temperature effects is derived, and the saturation magnetization of magnetic fluids at different temperatures are measured and the simulation analysis of temperature-structure-magnetic field coupling on magnetic fluid seals with large diameter in a wide temperature range is conducted to address the above problems. The structural deformation of the seal at the temperature range of -60~+80 ℃ is analyzed. Furthermore, the magnetic field distribution after the seal deformation is analyzed and the theoretical pressure resistance values of magnetic fluid seals at different temperatures are calculated.Thereby, the reason for changes of pressure resistance of magnetic fluid seals is clarified, which provides a new design method for magnetic fluid rotary seals with large diameter in a wide temperature range. The sealing experiments verify that the magnetic fluid seals designed using this method meet the sealing design requirements.

The local temperature of the swash plate increases close to the tempering temperature of the material under the swash plate axial pistion pump slipper pair working condition of high speed and large load. As a result, the residual austenite phase transformation causes the material surface expansion, the formation of static pressure support oil film, the surface hardness and durability decrease and other problems. Based on the premise of improving the friction and wear performance of the axial piston pump friction pair under high speed operation. A comparative analysis between the substitute material and the finished sample through composition analysis, high temperature treatment, friction and wear experiments is conducted. The results show that the average surface hardness of B material is increased by 17.7% compared with the original finished material at room temperature. After being stored at 400 ℃ for 10 h, the surface hardness of B material can still remain above 700 HV, the average maximum surface deformation of no more than 1 μm on the surface, and the average wear is reduced by 5.9% compared to the finished sample. The possibility of substitute material selection for swash plate axial piston pump under high speed operation is verified, which provides a reference for the follow-up research on material selection of swash plate axial piston pump.

Porous graphite materials significantly influence the performance of porous restrictors, which are key components of aerostatic guideways. This study employs the compressible Darcy-Forchheimer equation to fit experimental data and determine the permeability and inertia coefficients of porous graphite with five different porosities (18%, 17%, 13%, 12%, 11%). A CFD model incorporating these coefficients is established, accurately predicting the flow velocity and pressure drop within the porous medium, with an error margin within 5%. Further analysis under various supply pressures and loading conditions reveals that restrictors made from low-permeability graphite materials exhibit superior load-bearing capacity and gas film stiffness. Specifically, under a supply pressure of 0.45 MPa, the stability of the aerostatic block is significantly enhanced. Based on this research, an experimental platform for an aerostatic guideway with an adjustable gas film thickness is constructed using low-permeability restrictors. The guideway surface straightness is verified using a Keyence laser sensor, achieving better than 2.5 μm/600 mm.

In order to provide a simulation model for the excitation current and an integrated testing method for the main steam isolation quick-closing solenoid valve in current nuclear power plants, a mathematical model of mass-spring-damping system for solenoid valve core is first established. The excitation current characteristics of the solenoid valve are then simulated and analyzed. Furthermore, based on the current characteristics principle of the solenoid valve and the LabVIEW measurement and control platform, an integrated testing device is designed. This device is used to test the excitation current characteristics of the main steam isolation quick-closing solenoid valve. The test results show that the difference compared to the motion simulation results does not exceed 15%, indicating the rationality of the hardware and software design of the testing device. This testing method has been applied to the detection of quick-closing solenoid valve for main steam isolation valve of the “Hualong One” reactor unit at unit 5 of the Fuqing Nuclear Power Plant, where multiple practical tests have been carried out. The results meet the expectations, providing data and theoretical support for operation and maintenance of the solenoid valve.

To investigate the friction and wear characteristics of slipper pairs in high-pressure and large-displacement radial piston pumps under impact loading, this study established a transient friction wear model for the stator-slipper contact surface using ANSYS Mechanical software with ANSYS parametric design language programming. The dynamic friction wear of stator-slipper pairs is analyzed under varying working pressures, impact pressure amplitudes, and impact pressure times, supplemented by experimental validation. Key findings reveal that during the 0~0.6 s transient phase, wear primarily occurs between the central oil reservoir and pressure-equalizing groove on the slipper surface, accompanied by uneven wear patterns and stress concentration near the pin hole. The average error of relative value between simulation and experimental results is 8.99%. Through orthogonal experiment analysis and Kriging interpolation fitting, the sensitivity hierarchy of wear factors is determined as impact times, impact pressure amplitude and working pressure. Experimental results under three impact times within 60 minutes show a wear volume of 824.1379 mm³, demonstrating significant structural degradation caused by impact loading and validating the predictive capability of the proposed simulation model for slipper pair wear assessment.

Aimed at the problems of low static accuracy and limited dynamic performance of pump control unit, a fuzzy PID pressure stability control method based on load prediction feedforward compensation is proposed to improve the pressure control capability of the pump control unit. Firstly, mathematical models for the servo motor and fixed displacement pump in the pump control unit are established. Secondly, a load prediction algorithm based on long short-term memory neural network is designed, and we train the model, optimize the hyperparameter setting, calculate the evaluation index and carry out simulation verification. Furthermore, the proposed fuzzy PID control method based on load prediction feedforward compensation is analyzed through simulations. Finally, experimental studies validate the control method's effectiveness. The load prediction model achieves high prediction accuracy confirmed by evaluation metrics. With the use of the load prediction results as feedforward signal input compensation, the error between output pressure and expected pressure under two signal responses is reduced by 72.2% and 71.1% respectively compared with that of traditional PID controllers, enabling high-precision pressure stability control in the pump control unit.

In grain storage management, the curved surface structure of silo walls imposes stringent demands on the adhesion performance of wall-climbing robots. These robots must possess sufficient flexibility to adapt to curved surfaces while maintaining adequate rigidity to ensure stable support. We find that when a rigid suction cup is employed on walls with varying curvature, the limited deformation capacity of the suction cup body causes the sponge to adopt a “saddle-shaped” deformation during adhesion, which significantly diminishes the adhesion performance. To address this issue, we optimize the rigid suction cup structure, leading to the design of a semi-rigid suction cup with distributed rigid elements. The adhesion force experiments on various simulated substrates reveal that the rigid suction cup exhibit forces of 205.49 N, 307.56 N and 360.25 N on simulated substrates with curvature radii of 100 mm, 200 mm and 400 mm, respectively. In contrast, the semi-rigid suction cup exhibit slight fluctuations in adhesion force across different curved surfaces, yet maintain a stable overall value around 420 N. This solution achieves a significant enhancement in adhesion performance on complex curved surfaces, effectively reducing the risk of detachment during robot operation, which establishes a reliable foundation for expanding the application of wall-climbing robots in areas such as silos.

Deflector jet servo valve fault signals are limited and easily affected by noise under complex conditions, resulting in difficult feature extraction. This paper presents a fault diagnosis method combining starfish optimization algorithm-based variational mode decomposition, temporal convolutional network, and a self-attention bidirectional gated recurrent unit network. The starfish optimization algorithm selects variational mode decomposition parameters to improve decomposition accuracy and robustness. Main features are extracted from key intrinsic mode functions based on minimum envelope entropy. These features are entered into a temporal convolutional network and a self-attention-based bidirectional gated recurrent unit network to enhance fault classification. A fault simulation platform and dataset are built, with experiments under typical fault conditions. Results show that the fault recognition accuracy of the method achieves 97.33%, demonstrating strong robustness and high diagnostic performance.

The 6-DOF platform has been widely applied in various fields due to its exceptional performance characteristics including high precision, high load capacity, and high rigidity. To meet the spatial motion and positioning requirements of proton knife surgical beds, a 6-DOF motion positioning platform is developed. Firstly, based on workspace usage requirements, a reasonable structural design for the 6-DOF platform is implemented. Secondly appropriate hardware selection for the control system is carried out, along with programming design for the STM32 controller and the LabVIEW-based host computer. Subsequently, a prototype of the 6-DOF platform is fabricated, and control algorithm parameters are debugged. Finally, experiments are conducted to investigate the adaptability of the BP-PID control algorithm and nonlinear PID algorithm to different load cases, the real-time tracking error of slave cylinders under a master-slave cooperative control strategy, and the overall structural positioning error of the 6-DOF platform. Experimental results demonstrate that, for position control of a single electro-hydrostatic actuator under varying load cases, the BP-PID algorithm outperforms the nonlinear PID algorithm in terms of response speed and adaptive capability, while both algorithms exhibit almost no overshoot; During platform motion, the real-time cooperative error of slave cylinders remains within 0.43 mm, and the positioning accuracy of the 6-DOF platform is better than 0.05 mm/0.1°.

To investigate the dynamic characteristics of the working process of a helical tube hydraulic inerter, a numerical model of the helical tube hydraulic inerter is established. The dynamic mesh technique and User-defined Function are employed to simulate the dynamic changes in the internal flow field of the hydraulic inerter. The velocity and pressure field distributions at different time points are obtained, and the dynamic characteristics of the internal flow field are analyzed. Through bench tests, three excitation conditions—uniform speed input, square wave input, and sinusoidal input—are applied to the hydraulic inerter to explore the influence of excitation forms and impact velocity on the pressure drop, flow velocity, and friction coefficient of the helical tube. The results show that the hydraulic oil converges and diverges at the helical tube interface, forming significant vortices in the hydraulic cylinder. As the buffering progresses, the vortices intensify and the velocity distribution becomes uneven. The pressure drop is the largest under square wave excitation, followed by constant velocity excitation, and the smallest under sinusoidal excitation. The impact velocity is directly proportional to the pressure drop of the helical tube and inversely proportional to the friction coefficient. The findings provide a theoretical basis for the optimal design of hydraulic inerter devices.

The pilot solenoid valve regulates the internal oil flow of the shock absorber by controlling the main valve pressure, thereby affecting the damping force. A reasonable design of pressure-flow characteristics can broaden the range of damping adjustment to meet the needs of different working conditions. In this study, the pressure-flow characteristics of the pilot solenoid valve for an automobile continuous damping control shock absorber are optimized. Firstly, the hydrodynamic model and steady state force model of the oil flowing through each damping hole are established based on the fluid dynamics theory. The relationship between the electromagnetic force and the input current is determined with the electromagnetic magnetic circuit model of electromagnetic theory, and then the hydraulic simulation model is established. Subsequently, with the help of the solenoid valve performance test bench, experimental comparisons are carried out to verify the accuracy of the simulation model. Finally, the key structural parameters affecting the pressure-flow characteristics of the pilot solenoid valve were analysed to determine their importance using full factorial analysis of experimental design, and the key dimensions were optimised using a genetic algorithm, with the optimisation effect improved by 10.14%.

In response to the failure issues of the piston-slipper ball joint in high-speed axial piston pumps, dynamic characteristic analysis of the piston-slipper assembly is systematically conducted. Piston cavity dynamics model of the piston-slipper pair is established. The pressure variation within the piston chamber is analyzed by using computational fluid dynamics simulations. Subsequently, the interaction forces between the piston and slipper are quantified through multi-body dynamics simulation. Finally, the augmented Lagrangian method integrated with the steady-state structural analysis module of finite element software is employed to evaluate the deformation and stress distribution in both components. The results reveal that with increasing the load pressure, swash plate angle, and rotational speed leads to elevated negative pressure in the piston cavity, higher discharge pressure, and amplified interaction forces within the piston-slipper assembly. The maximum stress reach 80.4 MPa and deformation of the piston is 0.0213 mm respectively. For the slipper, the peak stress (168.4 MPa) and deformation (0.0057 mm) are localized at its closure. These findings provide critical insights for optimizing the design of piston-slipper ball joints in high-speed axial piston pumps.

This study addresses control challenges in mold demolding systems under nonlinear and time-varying load conditions. A tracking differential fuzzy PID compound control strategy is proposed to enhance system performance by integrating tracking differentiator technology with fuzzy PID control. The strategy features rapid error signal tracking and dynamic self-tuning of PID parameters. The co-simulation experiments combining AMESim and Simulink validate the proposed method. The results demonstrate significant improvements over conventional PID and fuzzy PID controllers: reduced response lag and steady-state error, enhanced tracking precision under high-frequency noise and superior disturbance rejection against unknown large-load interference. The control strategy maintains stable performance in complex operating environments while achieving faster dynamic response. These findings provide theoretical support for high-precision hydraulic servo control in mold demolding systems, particularly in scenarios requiring robust adaptability to nonlinear disturbances. The proposed method offers a practical solution for optimizing industrial mold demolding processes with time-varying dynamics.

In order to enhance the linear regulation capability of solenoid high-speed switching valves and achieve precise control of brake fluid flow, an influence factor characterizing the radial force on axial force of valve core is proposed. The numerical simulation of the internal flow field in the apply valve is carried out, additionally, it is found that the existing structure of valve seat and spool significantly affects brake fluid jet characteristics under Coanda Effect, coupled with asymmetric outlet geometry. These factors collectively increase the vortex probability and instability of flow field in the throttling region, which inducing substantial radial force during the opening and closing cycles. Structure optimization is implemented by reducing the spool spherical throttle ineffective area, implementing of variable-cone-angle surfaces on the valve seat and incorporating symmetrical supplementary outlet ports to improve flow field symmetry. The results show that the flow field of throttle area in new structure is more stable, the radial force on the spool is 0.1 N or less, which is with the opposite direction of the bias and is conducive to self-alignment of the spool. Finally, the new structure effectively weakening the radial force's impact on the linear regulation, reliability and life of the solenoid valve.

In order to reduce the power losses in construction machinery, a novel variable displacement opposed piston pump is proposed. The pump adds a piston on the basis of the traditional single-plunger pump, and the two pistons are arranged symmetrically, which not only attenuates the pressure fluctuation and eliminates the unbalance force of the single-plunger pump, but also realises variable displacement by adjusting the phase difference of the pistons. An AMESim model of the pump is developed and calibrated via equivalent modeling. The lag time of the distribution valve of this pump is compared with that of the traditional piston pump, and it is found that the lag time is relatively less, but there still exists a lag phenomenon, which led to a decrease in the performance of the pump, so the influence of different parameters of the inlet valve on the lag time of the distribution valve is comparatively analysed and the parameters are optimized using the orthogonal method. The results show that: the inlet valve parameters all have a greater impact on the inlet valve closing lag time, which is manifested as with the increase of spring stiffness, spring preload, spool diameter, respectively, the closing lag time is decreased by 10.9, 10.72, 1.73 ms, and is increased by 5.7 ms with the increase of spool mass; after parameter normalisation, the closing lag time of the outlet valve is decreased by 61.6%, 84.1%, and 8.9% with the increase of spring stiffness, spring preload, and spool diameter, respectively, with the increase of spool mass increasing by 37.1%. After orthogonal optimisation, the lag time of the outlet valve closure of the simulation model is decreased by 81.43%, which effectively reduces the return loss and improves the performance of the pump.

To study the impact of different dynamic sealing forms on dynamic characteristics of solenoid valve, based on the application cases of high-pressure solenoid valve, an AMESim model of pilot-operated solenoid valve is established. Three typical dynamic sealing forms, retaining ring, O-ring, and variseal are selected to investigate their respective impacts on the dynamic characteristics of solenoid valve. The result shows thatthe fact that the poor sealing effect of retaining ring leads to the opening and closing action of main valve of solenoid valve easily affected by environmental temperature results in negative impact on dynamic characteristics; Better sealing properties of O-ring leads to worse dynamic characteristics of solenoid valve, therefore a solution of cutting a pressure relief groove on sealing area is proposed;The sealing performance of variseal under normal and ultra-low temperature conditions is markedly different. Therefore the measures that should be considered in the design of the system are put forward to avoid affecting the dynamic characteristics of solenoid valve.

Slipper wear is a common failure in piston pumps. Aimed at the failures of the flow rate decrease and excessive vibration of the pump caused by slipper wear in the fuel piston pump of a certain type of aero-engine, a comprehensive failure diagnosis method is proposed within the framework of multiple disciplines including dynamics, tribology, fluid lubrication, and structural strength. The calculation and simulation of the oil film thickness, structural strength, and pv value of the slipper of this type of fuel piston pump under multiple operating conditions are carried out, and the associated mechanism between each operating condition and the wear failure is analyzed. The research results show that the structural strength of the slipper of the fuel piston pump meets the requirements within the full operating condition range, and the oil film characteristics are favorable when the rotational speed is below 4500 r/min. However, when the rotational speed of the fuel piston pump gradually increases, the proportion of the axial inertial force and centrifugal force acting on the slipper pair in the contribution to the pressing force gradually increases. When the rotational speed increases to 5000 r/min, the supporting force cannot effectively compensate for the external pressing force, resulting in the rupture of the hydrostatic oil film of the slipper pair. The slipper and the swash plate change from the fluid lubrication state to the boundary lubrication state or the direct contact state. Moreover, the pv value of the material of the slipper pair is in an over-limit state under the high rotational speed operating condition, which ultimately leads to wear failure.

The ultra-high-pressure large-diameter quick-opening valve, is the core component of an ultra-high-pressure gas release device, its flow characteristics and gas flow force play a decisive role in the system performance. A mass flow model of the quick-opening valve is established, and numerical simulations are carried out based on CFD technology. The flow coefficients under different valve port openings and opening pressures are calculated, and the reason why the flow coefficient decreases as the valve port opening increases is analyzed, which is the formation of non-choked flow and the energy loss caused by eddies. Numerical simulations of the gas flow force acting on the quick-opening valve are conducted. The steady-state gas flow force acting on the conical surface and end face of the quick-opening valve core are quantitatively calculated, and it is analyzed that their values fully meet the requirements for quick-opening. A mathematical model of the gas flow force acting on the valve port is obtained through numerical fitting. The research results provide theoretical support for the optimal design and experimental verification of the quick-opening valve.

Shear thickening fluid is a kind of intelligent material, and when applying the shear thickening fluid to the damper, we obtain the shear thickening fluid damper. Based on the reason that shear thickening fluid damper will be subjected to huge resistance due to the existence of velocity gradient when the fluid flows through small pores or gaps, the shear thickening fluid damper plays a key role in energy absorption and shock absorption. Through the way of Fluent simulation, the shear thickening fluid which is made of 20% mass fraction of nano-silica-polyethylene glycol solution is used as the working medium of the shear thickening fluid damper, and the flow of the shear thickening fluid in the damping holes is used to simulate the working process of the damper, and then draw the force-displacement hysteresis curves at different frequencies. The energy produced by the resistance force during the working process of the shear thickening fluid damper is calculated according to the results of the hysteresis curve to analyze the energy absorption effect. From the results, it is known that under the condition of the low-frequency working environment (f≤2 Hz), the force-displacement curve shows a good characteristic of symmetry, and the energy consumed in the retraction process of the damper is almost equal to that in the process of extension. But with the increase of frequency (f>2 Hz), the symmetric characteristic of the force-displacement curve becomes worse, and the energy consumed in the retraction process of the damper and the extension process are quite different.

The disc spring hydraulic mechanism is a key equipment in the power system, and its performance directly impacts the reliability of the system. Dynamic characteristic analysis of its key components aims to enhance operational stability. The mechanism's structural composition and operational principles are analysed firstly. Subsequently, Fluent-based simulations investigate the pressure variation characteristics in both rodless and rod cavities of the working cylinder piston. These simulations reveal the intrinsic correlation between piston velocity and pressure fluctuations. Further research focuses on gas pressure dynamics in the arc-extinguishing chamber during circuit-breaking operations, employing pressure cloud diagrams to analyse the spatial-temporal pressure distribution patterns in both the disc spring hydraulic mechanism and the arc-extinguishing chamber. Experimental validation confirms the accuracy of this dynamic analyses, establishes a theoretical foundation for optimizing mechanism design and improving operational stability.

There are problems of unstable control accuracy and imperfect matching of various types of equipment in current proportional control valve drivers, which cannot meet the flexibility, rapidly and localization requirements of modern electro-hydraulic control systems a digital-analog hybrid proportional control valve driver based on the GD32F450ZKT6 control chip is developed. The designed driver integrates a main control module circuit, power amplification circuit, ADC sampling circuit, and CAN/USB communication circuits, thereby enabling the realization of multiple command signal inputs, host computer parameter configuration, and output precision control functions. A test platform is further established to conduct the performance of the hybrid proportional control valve driver. The results show that the developed driver achieves an output accuracy of less than 2% under diverse signal command inputs, incorporates comprehensive control parameter configuration capabilities, and effectively satisfies the electro-hydraulic control requirements across multiple operational scenarios.

Due to strong nonlinearity, complex multivariable coupling and difficulty in real-time state observation, pneumatic soft robotic arms pose significant challenges for dynamic control. To address these issues, this study proposes a real-time motion control method integrating visual localization and neural network modeling. A vision system is constructed using YOLOv8 object detection and semi-global stereo matching to generate sequential datasets. A long short-term memory network is then employed to model the dynamic relationship between chamber pressure and end-effector position. The results show that compared to neural networks trained on discrete data, the long short-term memory model significantly reduces the mean absolute error in three-channel pressure prediction from approximately 1.65 kPa to 0.44 kPa. Further experiments demonstrate that the proposed method achieves average mean absolute error of 1.503, 1.506, 2.825 mm along the three spatial axes, validating the effectiveness of the vision-based sequential neural network control strategy in dynamic trajectory tracking of soft robotic arms.

Sticking mayoccur in drilling different coal rocks for a coal mine anti-impact drilling robot, and it may lead to drilling failure, which seriously affects the safety of drilling pressure relief operations, the quality and efficiency ofanti-impact pressure relief hole formation. To this end, an anti-sticking electro-hydraulic control strategy is proposed for coal rock drilling system. The mechanism of sticking is analyzed based on the variation of drilling parameters during drilling, and the drilling state is judged by combining support vector machines. The electro-hydraulic control strategy of anti-sticking based on sliding mode variable structure is designed. A joint simulation model of AMESim and MATLAB/Simulink is established, and the control characteristics of the anti-sticking is analyzed. The designed anti-sticking electro-hydraulic control experimental platform is executed for verification. The results indicate that the proposed anti-sticking electro-hydraulic control strategy can effectively identify the drilling status and reduce the risk of sticking, and can improve drilling efficiency and safety under different coal rock conditions.

Multi-degree-of-freedom hydraulic manipulators prominently exhibit strong joint coupling characteristics and large dynamic model errors, which leads to degraded control performance. To achieve high-precision pose control, a dual robust integral of sign error controller with prescribed performance function is proposed. Based on the prescribedperformance function, the transformed error signal is obtained, simultaneously limiting the rate and range of error convergence. Combined with the backstepping method, a dual robust integral of sign error controller is designed to suppress both matched and unmatched uncertainties, enhancing the robustness of system. The semi-global stability of the system and the boundedness of all signals are proved by Lyapunov stability theory. The results show that the proposed control strategy significantly improves the joint tracking accuracy and error convergence rate of multi-degree-of-freedom hydraulic manipulators, fully verifying the effectiveness of this control strategy.

To address the challenge in the domestic substitution of high-pressure hydraulic pumps, this paper proposes a tandem dual-output hydraulic pump power source. By connecting a secondary pump in series to the outlet of the primary pump, the system achieves stage-by-stage pressurization, fulfilling high-pressure requirements without modifying low-performance pumps. The tandem structure significantly reduces the pressure difference across single pumps, extends their service life, and isolates load impacts through accumulators. SimulationX-based analyses on flow pulsation and energy efficiency performance reveal the following results: Under conditions of 20 MPa and 1500 r/min, the flow pulsation rate is reduced by 37% compared to single-stage gear pumps. The system energy efficiency for driving high and low-pressure load hydraulic cylinders reaches 61% when adopting the proposed tandem power source, substantial improvement over the 36% efficiency of a single-stage variable displacement axial piston pump. These findings provide innovative insights for the design of power sources in complex high-pressure hydraulic systems.

The existing on/off high pressure large-flow electromagnetic unloading valves suffer from issues such as pressure regulation difficulty and discontinuous fluid supply, which struggle to meet the requirements of rapid response and on-demand adjustment of high-pressure pump output pressure in pumping station fluid supply systems. To address these challenges, an unloading valve utilizing proportional pilot valve control for main valve spool displacement regulation is developed, enabling on-demand rapid fluid supply and multi-range pressure modulation. A simulation model of the unloading valve is established using AMESim simulation software to investigate the influence patterns of main valve spring cavity, spring stiffness, spring preload, and damping hole diameter on the dynamic characteristics of the main valve, with subsequent experimental validation. The results demonstrate: Reduced spring cavity shortens both pressure build-up and relief times; Spring stiffness and preload primarily affect residual pressure and pressure relief duration; Damping hole diameter mainly impacts residual pressure and pressure rise time. Through prototype testing with optimized structural parameters, the experimental data revealed pressure rise time is 388 ms, pressure relief time is 436 ms, and residual pressure is 1.88 MPa.

The support and friction characteristics of the valve plate pair in piston pumps are crucial for reliability and lifespan. Various micro-texture models are constructed, and the entire pump flow field is simulated using Fluent software to compare the dynamic pressure characteristics and support forces of different micro-textures. The study further investigated the effects of slanted rectangle texture angle and rotational speed on oil film performance. Results show that all micro-textures improve dynamic pressure and support force, with slanted rectangle textures outperforming others. The dynamic pressure characteristicsincrease with pump speed but initially increase and then decrease with larger slanted rectangle texture angles, peaking at0.1455 MPa. The minimum oil film support force occurres at 75° angle, while the maximum friction is at 15°. The larger angles have a greater impact on friction coefficient at speeds above 2000 r/min, whereas below 2000 r/min, smaller angles have more significant effect.

It is crucial to select appropriate control parameters to improve the motion control accuracy of the pneumatic sliding table. However, the traditional trial-and-error method is inefficient and heavily reliant on experience of parameter adjusters. Therefor, a novel improved particle swarm optimization algorithm is presented. This algorithm applies an improved Gaussian-sine chaotic mapping technique to generate initial particles so as to enrich the diversity of the population. It introduces sine disturbance and Lévy flight strategy to help particles escape local optima. Additionally, it integrates the sine-cosine algorithm and an improved slime mold algorithm to improve search accuracy. The experimental results from linear active disturbance rejection motion control tests on the pneumatic sliding table show that the proposed novel particle swarm optimization algorithm can effectively improve control accuracy. Compared with the trial and error method,it reduces the maximum steady-state error by 15.9% and 23.4% respectively when tracking sinusoidal trajectories with an amplitude of 150 mm and frequencies of 0.25 Hz and 0.5 Hz. And it reduces the maximum steady-state error by 13.5% when tracking multi frequency curves.

By designing different anti-friction lubricating structures and comparing the oil film characteristics, the influence of different anti-friction lubricating structures on the servo hydraulic cylinder to overcome the radial load and reduce the friction is studied, the best shape structure of anti-friction lubricating structure is obtained, and tests are verified. Based on the rectangular structure of anti-friction lubricating, I-shaped structure and trapezoidal structure are proposed. The pressure distribution and bearing capacity characteristic curves of different anti-friction lubricating structures are obtained by theoretical analysis and flow field simulation. The anti-friction lubricating structure of trapezoidal structure can provide more bearing capacity, and the temperature rise of oil film is smaller. The anti-friction lubricating structure can effectively overcome the radial load on the piston rod and reduce the friction of the servo hydraulic cylinder. The results show that the oil film characteristics of different anti-friction lubricating structures are different, which can effectively overcome the partial load, greatly reduce the friction of the servo hydraulic cylinder, and improve the control precision and service life of the servo hydraulic cylinder.

Aiming at the challenges of poor road conditions, complex environments, this study proposes an active vibration reduction scheme using a tractor electro-hydraulic suspension based on digital valves in order to improve stability and comfort during tractor transportation. Highly responsive digital hydraulic valves are used to adjust the speed and displacement of the implement hitch cylinder in real time to counteract vibration. Firstly, a dynamics model of tractor vibration system with suspended implements is derived. A sliding mode controller is designed, and a simulation model is developed to investigate the active vibration reduction performance under random road, sinusoidal road, and pulse road conditions. The results demonstrate that effective vibration suppression is achieved under all three road conditions. Specifically, under a 20 km/h random road excitation, the peak vertical acceleration of the tractor can be reduced by the active vibration reduction system of electro-hydraulic suspension from 2.13 m/s² to 1.01 m/s², and the root mean square value decreases from 0.84 m/s² to 0.28 m/s², achieving a 63% reduction compared to passive vibration reduction systems, which results in excellent vibration reduction.

To address the issue of insufficient adjustability of low-frequency dynamic characteristics in heavy-duty special vehicle mount systems, this study proposes a magnetorheological fluid mount with controllable multi-inertial channel combined squeezing mode. A multi-channel magnetorheological fluid damper is developed, and experimental methods are employed to validate the switching effect of controllable flow channels. An aggregate parameter model for the magnetorheological fluid mount with controllable multi-inertial channel combined squeezing mode and a model of magnetorheological fluid mount system for 1/4 heavy-duty special vehicle are established. Finally, dynamic characteristics and vibration isolation performance are investigated based on these models. The results demonstrate that by the application of large current on different inertial channels, the peaks and peak frequencies of dynamic stiffness and hysteresis angle in the magnetorheological fluid mount become adjustable within 0~50 Hz. Additionally, under squeezing mode operation, the mount exhibits high-stiffness and high-damping characteristics at low frequencies.