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ObjectiveThe grid fault of voltage drop will cause severe variations to the load of wind turbines, and seriously affect the safe and stable operation of wind turbines. With the increasing of the wind turbine scale, the blade length and the tower height increase continually, leading to the increase of the sensitivity of load characteristics to the system parameter fluctuations. Therefore, it is necessary to study the load and vibration characteristics of key components in the process of grid voltage drop.MethodsA data interaction method based on dynamic link library and Socket communication was proposed, and a joint simulation method of Simulink and Bladed was established. Firstly, based on a 3.4 MW wind turbine model, the joint simulation platform was verified by a given wind speed variation condition. Then, the relationship between the overall performance of the unit and the load of the blade and tower during low voltage ride through (LVRT) was studied.ResultsThe amplitude of grid voltage drop has a great impact on the generator power, and has little impact on the wind turbine control parameters. In the process of LVRT, the blade pitch angle and rotational speed of the wind turbine fluctuate for a long time, the load change at the outer blade span is greater than that at the inner blade span, the blade tip displacement increases, and the vibration frequency of the tower is close to the natural frequency. These potential risks should be considered in wind turbine design.ConclusionThe joint simulation platform can effectively simulate the aerodynamic performance of the wind turbines and the transient characteristics of the component loads, and provide a reference for the optimal control of the unit.

Copyright of Power Generation Technology is the property of Power Generation Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A knotter is a core component for the automatic bundling of agricultural materials, and a knotter with double-fluted discs is one type. Currently, the research on knotters with double-fluted discs has gradually transitioned from structural design to reliability optimization. To address rope-clamping failures in the rope-clamping drive mechanisms in knotters, the specific failure position of the rope-clamping mechanism and the failure causes were analyzed first. The redesign of the rope-clamping drive mechanism in knotters with double synclastic fluted discs was proposed, including structure optimization and 3D modeling using the GearTrax/KISSsoft and SolidWorks software. A virtual prototype model of a knotter with a flexible rope was established by combining ANSYS with the ADAMS software. A rigid–flexible coupling dynamic simulation of the knotter was carried out using ADAMS, and the simulation results were used as the data input for the ANSYS nCode DesignLife module for the fatigue life simulation of the weak parts (the worm shaft) of the knotter. The operation test results for the rope-clamping drive mechanism indicate that the redesigned rope-clamping drive mechanism is reliable in transmission, with a rope-clamping success rate of 100%. The actual operation times for the worm shaft exceed the minimum fatigue life obtained through joint simulation. The applied joint simulation method has high simulation accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming at the problem that during continuous braking of pure electric commercial vehicles, low air source pressure will lead to slower braking force response speed of drive axle coupling and affect braking energy recovery efficiency, a scheme of uncoupled braking energy recovery system (URBS) based on proportional relay valve was proposed. Firstly, based on the hysteresis characteristics of the proportional relay valve, the feed-forward-single neuron PID control method was adopted to realize the accurate output of braking air pressure. Secondly, taking the battery SOC and vehicle speed as the constraints, the pressure supply mode was determined according to the pressure signal of the air source, and the uncoupled braking energy recovery control strategy was formulated. Finally, a joint simulation platform was built based on AMESim, MATLAB/Simulink and TruckSim, and a single braking condition and cyclic conditions were selected to verify the effect of the braking force coupling and the braking energy recovery of the system. The results show that URBS based on proportional relay valve can achieve rapid response of coupled braking force, with the time of less than 0.1 second to reach 75% of steady-state pressure value. The effective braking energy recovery rates under CHTC-HT（China heary-duty commercial vehicle test cycle for heavy truck) and C-WTVC(China world transient vehicle cycle) conditions are 10.13% and 17.17%, respectively. The proposed URBS scheme can effectively improve the response speed and coupling accuracy of coupled braking force of the drive axle, and can provide reference for the design of pneumatic URBS schemes for pure electric commercial vehicles.

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Hebei University of Science & Technology is the property of Hebei University of Science & Technology, Journal of Hebei University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT As weeds cannot be eradicated in corn fields, a crab claw toe was used as the research object and combined with the agronomic requirements of corn fields to design a bionic weed claw suitable for corn fields. The contour curve of the crab claw toe was extracted and fitted through the Matlab image processing technology and fitting tool to establish a bionic claw finger 3D model using Solid works. According to the mechanical soil dynamics theory of dynamics analysis, the root–soil aggregates are easily broken, loosened, and drained under the action of the bionic claw fingers. Based on single image inverse reconstruction technology, the weed root system–soil aggregates discrete meta-model was established. Recur Dyn was used in the bionic weed claw kinematics simulation to verify the reliability of the movement of the mechanism and to realise the expected action of the weeding operation. We analysed the movement speed, displacement, and trajectory of soil particles in different depth layers through the joint simulation and comparison test. Using the mechanism of weeding and resistance reduction of the bionic weeding claw, under the same working conditions, the average resistance reduction rate of the bionic claw finger compared with the flat claw finger in the grasping process was 16.4%. The resistance of grass roots was reduced 23.3%, making it easier to pull out the more intact grass roots.

In this study, the joint simulation flow of Adams and AMESim on the kinematics and contact dynamics of the marine high-power hydraulic drive gear clutch is studied, and the joint simulation interactive operation interface is developed. With the given parameters, the visual calculation results can be output. The simulation results show that the dynamic characteristics and impact load of the gear clutch during the axial engagement are affected by the torsional stiffness of the active end and the end face structure of the gear. The maximum opening pressure of the pressure reducing valve is 2.5 MPa, and the maximum thrust under this pressure is 1.884×105 N. When the inner and outer rings collide, the oil pressure will rise rapidly. If the flow of the pressure reducing valve is insufficient, the oil inlet will leak. After multiple joint simulations, it is found that the clutch engagement and disengagement process can be completed around 4 s when the inlet pressure is between 0.008 MPa and 0.01 MPa.

To address the challenges of sinking, imbalance, and complex control systems faced by hexapod robots walking on lunar soil, this study develops an umbrella-shaped foot lunar exploration hexapod robot. The overall structure of the robot is designed to mimic the body structure of insects. By incorporating a four-bar linkage mechanism to replace the commonly used naked joints in traditional hexapod robots, the robot reduces the number of degrees of freedom and simplifies control complexity. Additionally, an extension mechanism is added to the robot's foot, unfolding into an umbrella shape to provide a larger support area, effectively addressing the issue of foot sinking instability during walking. This study adopts and simplifies the Central Pattern Generator (CPG) model to generate stable periodic control signals for the robot's legs. Precise control of the extension mechanism's unfolding period is achieved through mapping functions. A joint simulation platform using Solid Works and Matlab is established to analyze the stability of the robot's walking. Finally, walking experiments are conducted on the prototype, confirming the smooth walking of the lunar exploration hexapod robot. The results indicate that the designed lunar exploration hexapod robot has a reasonable structure, excellent stability in motion, and the CPG control scheme is feasible. [ABSTRACT FROM AUTHOR]

The electro-hydrostatic actuator (EHA) is a new type of high-performance servo actuator that originated in the field of aerospace, and it is gradually becoming a common basic component for various types of large equipment. A miniature EHA, mainly composed of a micro two-dimensional (2D) piston pump and a brushless DC motor, is designed in this article by simplifying the system structure. This paper analyzes the structure and working principle of this EHA and establishes the mathematical models of the brushless DC motor, micro two-dimensional pump, and hydraulic cylinder. Field-oriented control (FOC) is used to drive the brushless DC motor, and the models of the controller are established in Simulink. Furthermore, the models of the mechanical and hydraulic systems of the miniature EHA are established in AMESim. In addition to this, a prototype of this miniature EHA was fabricated in this paper and an experimental platform was built for experiments. In the joint simulation environment, the rise time of the EHA system at 6000 r/min is 0.158 s and the frequency response amplitude attenuation to −3 dB has a bandwidth of 20 Hz. On the other hand, the constructed miniature EHA prototype was dynamically characterized to obtain a rise time of 0.242 s at 6000 r/min and a bandwidth of 13 Hz. In this paper, the feasibility of the design scheme of the miniature EHA system is verified, and its excellent dynamic properties are verified with simulation and experiment. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Test & Measurement Technology is the property of Publishing Center of North University of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The application feedback on existing silicon nitride ceramic bearings and RCF experimental research all indicate that the primary failure mode of silicon nitride ceramic bearings is material spalling on the contact surface. Spalling failure occurs due to the initiation and propagation of cracks under rolling contact. However, silicon nitride ceramic bearings, owing to their unique manufacturing method, inevitably exhibit defects and cracks. Therefore, as silicon nitride ceramic bearings are increasingly prevalent, reducing the probability of spalling failure is crucial for extending their service life. This can only be achieved by gaining a clear understanding of the crack initiation and expansion mechanisms in silicon nitride ceramic bearings. This paper is based on silicon nitride rolling friction experiments. It involves the joint simulation of Franc3D-V8.4 and ABAQUS2020, wherein the crack front SIFs are calculated for each load contact position of the surface crack on the silicon nitride ceramic bearing ring during cyclic movement. The study also delves into the determination of the maximum effective stress intensity factors and explores the influence of the initial crack depth on the cycle life and direction of crack propagation. The research yields several valuable conclusions. The findings of this research offer theoretical guidance for formulating grinding technologies for silicon nitride rings and adjusting and controlling working parameters of silicon nitride ceramic ball bearings. These insights are crucial for enhancing the reliability and longevity of silicon nitride ceramic bearings in practical applications. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The research on electric drive wheel technology is an important direction of the research on the new energy drive system in the future. With the increasing requirements of the electric drive wheel on the speed, the oil churning power loss has become a non-negligible part, even up to 50%-80% of the total power loss. The existing calculation method of churning loss mainly adopts simple empirical formula, which cannot be applied to complex planetary gear transmission. The splash lubrication of the two-stage planetary gear drive is simulated by computational fluid dynamics (CFD) software and C language user defined function (UDF), and the visualization of oil gas two-phase transient flow field is realized; by extracting the surface pressure and the viscous force, the churning loss of the sun gears, planet gears and planet carriers are obtained; the simulation and analysis of the 25 working conditions show that the churning loss varies with the immersion depth and speed; the results show that the oil churning power loss increases with the oil immersion depth and the speed, and there is no obvious inflection point. To achieve the minimum oil stirring loss, the minimum oil immersion depth should be taken on the premise of ensuring full lubrication.

A knotter is a core component for the automatic bundling of agricultural materials, and a knotter with double-fluted discs is one type. Currently, the research on knotters with double-fluted discs has gradually transitioned from structural design to reliability optimization. To address rope-clamping failures in the rope-clamping drive mechanisms in knotters, the specific failure position of the rope-clamping mechanism and the failure causes were analyzed first. The redesign of the rope-clamping drive mechanism in knotters with double synclastic fluted discs was proposed, including structure optimization and 3D modeling using the GearTrax/KISSsoft and SolidWorks software. A virtual prototype model of a knotter with a flexible rope was established by combining ANSYS with the ADAMS software. A rigid–flexible coupling dynamic simulation of the knotter was carried out using ADAMS, and the simulation results were used as the data input for the ANSYS nCode DesignLife module for the fatigue life simulation of the weak parts (the worm shaft) of the knotter. The operation test results for the rope-clamping drive mechanism indicate that the redesigned rope-clamping drive mechanism is reliable in transmission, with a rope-clamping success rate of 100%. The actual operation times for the worm shaft exceed the minimum fatigue life obtained through joint simulation. The applied joint simulation method has high simulation accuracy.

This study investigates the efficiency and safety of regenerative brake energy recuperation systems for electric vehicles. A three-input single-output fuzzy controller is developed to allocate hydraulic and electric braking forces, considering brake intensity, vehicle speed, and battery SOC's impact on regenerative braking performance. Fuzzy neural networks are utilized due to their effectiveness in solving complex, nonlinear, and fuzzy systems, along with their robustness to parameter changes and external disturbances. The fuzzy process of the controller is optimized using a self-tuning algorithm for designing membership function parameters, resulting in a fuzzy neural network controller. Moreover, electric and hydraulic braking forces are redistributed. Simulation using AVL Cruise software is conducted under NEDC and FTP-75 working conditions. The suggested brake energy recovery control approach using fuzzy neural networks successfully recovers braking energy, achieving energy recovery efficiencies of 14.52% and 39.61% under NEDC and FTP-75 conditions, respectively.

Osteochondral grafts are used for repair of focal osteochondral lesions. Autologous grafts are the gold standard treatment; however, limited graft availability and donor site morbidity restrict use. Therefore, there is a clinical need for different graft sources/materials which replicate natural cartilage function. Chitosan has been proposed for this application. The aim of this study was to assess the biomechanics and biotribology of a bioresorbable chitosan/chitosan-nano-hydroxyapatite osteochondral construct (OCC), implanted in an in vitro porcine knee experimental simulation model. The OCC implanted in different surgical positions (flush, proud and inverted) was compared to predicate grafts in current clinical use and a positive control consisting of a stainless steel graft implanted proud of the cartilage surface. After 3 h (10 800 cycles) wear simulation under a walking gait, subsidence occurred in all OCC samples irrespective of surgical positioning, but with no apparent loss of material and low meniscus wear. Half the predicate grafts exhibited delamination and scratching of the cartilage surfaces. No graft subsidence occurred in the positive controls but wear and deformation of the meniscus were apparent. Implanting a new chitosan-based OCC either optimally (flush), inverted or proud of the cartilage surface resulted in minimal wear, damage and deformation of the meniscus.

In recent years, wind turbines are becoming larger, which will exacerbate the complexity of loads Complex load change affect the output power quality and wind turbine service life so that must be studied. Pitch control is usually used to reduce wind turbine load. In this paper, based on the Light Detection and Ranging (LiDAR) technology and incremental feedforward control theory, an incremental feedforward collective pitch controller is proposed. The controller can be directly superimposed on the traditional collective pitch controller so that the incremental pitch angle can fully compensate wind influence. The effectiveness of the controller is verified by multi-software platform joint simulation and hardware-in-the-loop experiment. The results show that the controller can effectively reduce the wind turbine power and load fluctuation when the variation trend of wind speed in the rotor plane estimate by LiDAR data is the same as the actual wind speed.

In the process of meshing transmission of nonbevel gear, there are problems of vibration and impact. Therefore, a simulation control method of non-bevel gear transmission based on ADAMS and MATLAB is proposed. Firstly, the design modeling of non-bevel gear is briefly introduced, and the influence of order and eccentricity on its transmission ratio is analyzed. Then, the established nonbevel gear model is imported into ADAMS, and the constraints, motion pairs, driving force, input and output variables are set. The data transfer relationship is established by using ADAMS/Control module and MATLAB/Simulink interface. The non-bevel gear mechanical system module is generated in MATLAB/Simulink. Finally, the co-simulation control system is built in MATLAB/Simulink module, and the control simulation analysis is carried out. The results show that: by comparing and analyzing the simulation results with only constant input and adding PI control module, it can be seen that after adding PI control module, the amplitude and frequency of the angular velocity and angular acceleration curve of the driving wheel are significantly reduced, that is, the vibration and impact in non-bevel gear transmission are reduced, which verifies the correctness and feasibility of the control strategy. It provides a new method for the control design and development of vibration damping performance of non-bevel gear drive. The results are beneficial to the application and popularization of non-bevel gears. [ABSTRACT FROM AUTHOR]

This paper analyzes the typical technical problems arising from dumping and tamping collision interferences in the working faces of conventional mechanized solid backfilling mining (SBM). Additionally, the technical and consecutive characteristics of the solid intelligent backfilling (SIB) method, the execution device, and the corresponding process categories of the SIB process are analyzed. A design for an SIB process flow is presented. Critical algorithms, including automatic recognition and optimization planning based on the cost function and laying the algorithm foundation, are proposed to develop a backfilling process control system. A joint simulation test system is built on a MATLAB/Simulink simulation toolkit (MSST) to simulate and test the optimized algorithms. The results show that the optimized algorithm can realize the automatic optimization planning and automatic interference-recognition adjustment of the backfilling process under actual engineering conditions. In conclusion, this paper analyzes typical technical problems in the conventional backfilling process, designs the SIB process flow, and develops key algorithms to achieve the automatic control of the backfilling process. [ABSTRACT FROM AUTHOR]

The contact parameters of joint interfaces have a great influence on the dynamic performance of the machine tool, and the dynamic performance determines the machining precision of the machine tool. Therefore, it is important to accurately identify the contact parameters of joint interfaces to improve the machining precision of the machine tool. In this paper, a method of identifying the joint interface stiffness parameters based on a joint simulation in Matlab and Ansys is first proposed, and then stiffness parameters of joint interfaces between the bed and column of the precision grinding machine are identified by applying the method. Finally, the feasibility and high efficiency of the proposed method are proved by comparing the natural frequencies of the simulation and the experiment. In order to further analyze the influence of joint contact parameters on the performance of the joint interfaces, the theoretical model of the normal stiffness of the joint interfaces based on fractal geometry is amended and verified by taking into account the asperity interaction and elastic–plastic deformation. Then, the modified model is extended to a three-dimensional model, which is more in line with the actual situation. Finally, the influencing factors of the joint interface stiffness are analyzed. The conclusions of this paper are of great significance in the dynamic performance analysis and structural design of machine tools. [ABSTRACT FROM AUTHOR]

The design of spacecraft servo mechanism plays an important role in the control of the spacecraft. The research of control algorithm and the construction of simulation platform have important practical value. This paper modelles and simulates the mechanical, electrical, hydraulic parts of the aerospace servo mechanism. The overall model of the whole servo system is established. The mechanical structure of the servo mechanism is built in ADAMS and the hydraulic module is built by AMESim. Based on HM theory, the robust controller is built with Matlab toolbox. Combined with the dynamics model of ADAMS and AMESim, as well as the Matlab controller model, the joint simulation of each module is realized. Through the joint simulation technology, the simulation of physical system is more realistic, and the experimental results are also displayed more intuitively. This simulation has a good guiding significance for the design and construction of actual spacecraft servo mechanism system. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quadruped robot has become a hot topic in the international community because it can adapt to the complex terrain environment using the way of detached feet. In view of the lack of bionic characteristics of the foot trajectory of the quadruped robot and the inconsistency between the walking effect and that of mammals, this study establishes the three-joint leg mechanism with the help of SolidWorks, obtains the leg kinematic model, and analyzes the leg trajectory motion by referring to the laws of biological movement. Combined with bionic characteristics and based on compound cycloid and quintic polynomial, a foot trajectory of compound cycloid quintic polynomial is planned in this study, which not only meets the law of bionic motion, but also meets the requirements of trajectory planning. In this study, MATLAB and ADAMS co-simulation is used to realize the kinematic simulation of single leg, and the prototype and control system are used to realize the physical motion of single leg. The experimental results show that the single-leg motion of the quadruped robot can realize the planned trajectory curve motion, and the acceleration is 0 at the second second, which is basically consistent with the simulation trajectory effect, which verifies the effectiveness of the proposed algorithm to a certain extent. [ABSTRACT FROM AUTHOR]

A motor synchronization control strategy based on fuzzy PID algorithm was proposed to solve the problem of unsynchronized track under tail offset load. Firstly, the hydraulic simulation of the self-moving tail was carried out by AMESim through the mathematical model of the track force. Then, taking the multi-way valve as the controlled object, the motor angular displacement as the control variable, and the valve opening as the controlled variable, the fuzzy PID control model was established by MATLAB/Simulink, and the AMESim/MATLAB co-simulation model was established. Finally, by adjusting the current signal of the multi-way valve, the opening of the multi-way valve was changed, and the synchronization of the left and right motors was realized. The co-simulation results show that the fuzzy PID control strategy can realize the synchronization of the left and right motors within 3 s and overcome the interference within 1 s. The results show that the adjustment time and overshoot of the left motor speed are respectively reduced by 1.97 s and 35.53%. The fuzzy PID algorithm not only improves the anti-interference ability, but also makes the system obtain better dynamic response performance, which provides a certain technical reference for the track deviation prevention in the later underground coal mining. [ABSTRACT FROM AUTHOR]

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For the hydraulic drilling tool under deep water, an integrated structure of a water hydraulic electrohydraulic motor is proposed, which consists of three parts: pump unit, motor unit, and DC brushless motor. The two-dimensional piston in the pump unit has two degrees of freedom of motion: rotation and reciprocation, so it is compact and can be matched with a high-speed motor to become a high-speed motor pump; the two sets of plungers in the motor unit are balanced with two end-facing cam drive mechanisms to achieve axial force, which is also suitable for high-speed rotation. In this paper, the mechanical structure and working principle of the electrohydraulic motor are described, the mathematical model of the output characteristics of the electrohydraulic motor is established, and the joint simulation model of Adams and AMESim is built, then the relationship between the dynamic characteristics of the electrohydraulic motor and the structure and working parameters is studied. The results show that the higher the speed of the pump unit, the smoother the characteristics of the electrohydraulic motor, when the motor speed is increased from 1000 r/min to 3000 r/min, the pulsation amplitude of the electrohydraulic motor speed is decreased by 200%; the plunger sub of the motor unit should take proper clearance, if the plunger sub clearance is increased to $12~\mu \text{m}$ , the output speed is decreased by 40% and the leakage volume is increased by 25 times; the motor unit should have proper back pressure to facilitate the smoothness and life of the motor, when the back pressure value is increased from 0.2 MPa to 1.2 MPa, the pressure pulsation at the beginning of the start-up is also greatly reduced.

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to improve the active safety of vehicles, the control strategy of the vehicle automatic emergency braking system is studied. The hierarchical control idea is used to model the control strategy. The upper controller is a collision time model for the decision-making of vehicle braking deceleration, and the collision time threshold is determined under the condition of considering comfort. According to the braking deceleration output by the upper controller, the lower controller controls the vehicle by adjusting the throttle opening and braking pipeline pressure through PID control. Based on the typical test conditions of C-NCAP, a joint simulation test of CarSim and Matlab/Simulink for hierarchical control strategy is carried out. In order to achieve further verification, several groups of test conditions are conducted, and finally its effectiveness is verified, which can ensure the safety of drivers. [ABSTRACT FROM AUTHOR]

A new approach is proposed for simultaneous diagonalisation of variance-covariance matrices to generate spatially orthogonal factors using based on simulated annealing method. Simultaneous diagonalisation was applied to three quality attributes of a coal seam. The proposed method was successful in diagonalisation due to creating factors with cross-variograms that lie in tighter intervals compared with minimum/maximum autocorrelation factors (MAF). Simulation through the proposed approach showed variable dependent results in terms of reproducing mean values, variances, correlation coefficients, and auto-variograms of variables. However, the new approach showed advantage over MAF in reproducing the cross-variograms of variables, especially in the downhole direction. [ABSTRACT FROM AUTHOR]

The process of intelligent multi-objective parametric optimization design for mirrors is discussed in detail in this paper, with the error of the mirror surface shape and the total mass being examined as the optimization objectives. The establishment of complex objective functions for solving the optimization problem of the mirror surface shape error was realized, and manual modification of the model was avoided. Moreover, combining this with a non-dominated sorting genetic algorithm (NSGA) helped the Pareto front move towards an ideal optimal set of solutions. To verify the effectiveness of the proposed method, an aluminum alloy mirror with an aperture of 140 mm was taken as an example. The Pareto optimal solution set of the mass and surface shape error under 1 g gravity was obtained for finding the required solution and satisfying the optimization goal. In addition, this method is applicable to other complex structural design problems. [ABSTRACT FROM AUTHOR]

To address the challenges of sinking, imbalance, and complex control systems faced by hexapod robots walking on lunar soil, this study develops an umbrella-shaped foot lunar exploration hexapod robot. The overall structure of the robot is designed to mimic the body structure of insects. By incorporating a four-bar linkage mechanism to replace the commonly used naked joints in traditional hexapod robots, the robot reduces the number of degrees of freedom and simplifies control complexity. Additionally, an extension mechanism is added to the robot’s foot, unfolding into an umbrella shape to provide a larger support area, effectively addressing the issue of foot sinking instability during walking. This study adopts and simplifies the Central Pattern Generator (CPG) model to generate stable periodic control signals for the robot’s legs. Precise control of the extension mechanism’s unfolding period is achieved through mapping functions. A joint simulation platform using Solid Works and Matlab is established to analyze the stability of the robot’s walking. Finally, walking experiments are conducted on the prototype, confirming the smooth walking of the lunar exploration hexapod robot. The results indicate that the designed lunar exploration hexapod robot has a reasonable structure, excellent stability in motion, and the CPG control scheme is feasible.

The electro-hydrostatic actuator (EHA) is a new type of high-performance servo actuator that originated in the field of aerospace, and it is gradually becoming a common basic component for various types of large equipment. A miniature EHA, mainly composed of a micro two-dimensional (2D) piston pump and a brushless DC motor, is designed in this article by simplifying the system structure. This paper analyzes the structure and working principle of this EHA and establishes the mathematical models of the brushless DC motor, micro two-dimensional pump, and hydraulic cylinder. Field-oriented control (FOC) is used to drive the brushless DC motor, and the models of the controller are established in Simulink. Furthermore, the models of the mechanical and hydraulic systems of the miniature EHA are established in AMESim. In addition to this, a prototype of this miniature EHA was fabricated in this paper and an experimental platform was built for experiments. In the joint simulation environment, the rise time of the EHA system at 6000 r/min is 0.158 s and the frequency response amplitude attenuation to −3 dB has a bandwidth of 20 Hz. On the other hand, the constructed miniature EHA prototype was dynamically characterized to obtain a rise time of 0.242 s at 6000 r/min and a bandwidth of 13 Hz. In this paper, the feasibility of the design scheme of the miniature EHA system is verified, and its excellent dynamic properties are verified with simulation and experiment.

The application feedback on existing silicon nitride ceramic bearings and RCF experimental research all indicate that the primary failure mode of silicon nitride ceramic bearings is material spalling on the contact surface. Spalling failure occurs due to the initiation and propagation of cracks under rolling contact. However, silicon nitride ceramic bearings, owing to their unique manufacturing method, inevitably exhibit defects and cracks. Therefore, as silicon nitride ceramic bearings are increasingly prevalent, reducing the probability of spalling failure is crucial for extending their service life. This can only be achieved by gaining a clear understanding of the crack initiation and expansion mechanisms in silicon nitride ceramic bearings. This paper is based on silicon nitride rolling friction experiments. It involves the joint simulation of Franc3D-V8.4 and ABAQUS2020, wherein the crack front SIFs are calculated for each load contact position of the surface crack on the silicon nitride ceramic bearing ring during cyclic movement. The study also delves into the determination of the maximum effective stress intensity factors and explores the influence of the initial crack depth on the cycle life and direction of crack propagation. The research yields several valuable conclusions. The findings of this research offer theoretical guidance for formulating grinding technologies for silicon nitride rings and adjusting and controlling working parameters of silicon nitride ceramic ball bearings. These insights are crucial for enhancing the reliability and longevity of silicon nitride ceramic bearings in practical applications.

The safety transfer on the sea is threatened by wind, wave and surge loads. An offshore gangway ensures smooth and safe transfer by compensating the ship's motion. In a mixed offshore gangway system, the transfer gangway is a huge asymmetric load on top of the stable platform, and the displacement of its center of gravity causes it to exert a large dynamic load on the stable platform. A dynamic model of the offshore gangway under dynamic load is established in this work. The Lagrange equation is used to establish the dynamic model of the transfer gangway; the equivalent center of gravity method is used to visualize its dynamic load. The dynamic of the stable platform is modeled by the virtual work principle. Finally, the accuracy of the mathematical model was verified by the joint simulation. Simulation results indicate that under the influence of dynamic load, the tractive force of the second drive support chain is 2–3 times greater than the tractive force of the first and third drive support chains. With the same excitation, the tractive force of the second drive support chain is 2.83 times higher than that under the static load. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The contact parameters of joint interfaces have a great influence on the dynamic performance of the machine tool, and the dynamic performance determines the machining precision of the machine tool. Therefore, it is important to accurately identify the contact parameters of joint interfaces to improve the machining precision of the machine tool. In this paper, a method of identifying the joint interface stiffness parameters based on a joint simulation in Matlab and Ansys is first proposed, and then stiffness parameters of joint interfaces between the bed and column of the precision grinding machine are identified by applying the method. Finally, the feasibility and high efficiency of the proposed method are proved by comparing the natural frequencies of the simulation and the experiment. In order to further analyze the influence of joint contact parameters on the performance of the joint interfaces, the theoretical model of the normal stiffness of the joint interfaces based on fractal geometry is amended and verified by taking into account the asperity interaction and elastic–plastic deformation. Then, the modified model is extended to a three-dimensional model, which is more in line with the actual situation. Finally, the influencing factors of the joint interface stiffness are analyzed. The conclusions of this paper are of great significance in the dynamic performance analysis and structural design of machine tools.

This paper analyzes the typical technical problems arising from dumping and tamping collision interferences in the working faces of conventional mechanized solid backfilling mining (SBM). Additionally, the technical and consecutive characteristics of the solid intelligent backfilling (SIB) method, the execution device, and the corresponding process categories of the SIB process are analyzed. A design for an SIB process flow is presented. Critical algorithms, including automatic recognition and optimization planning based on the cost function and laying the algorithm foundation, are proposed to develop a backfilling process control system. A joint simulation test system is built on a MATLAB/Simulink simulation toolkit (MSST) to simulate and test the optimized algorithms. The results show that the optimized algorithm can realize the automatic optimization planning and automatic interference-recognition adjustment of the backfilling process under actual engineering conditions. In conclusion, this paper analyzes typical technical problems in the conventional backfilling process, designs the SIB process flow, and develops key algorithms to achieve the automatic control of the backfilling process.

Arterial‐branch intersections are important components of urban road network but are greatly ignored of its role in maintaining an efficient traffic operation in regional networks. Arterial‐branch intersections are generally featured with significant fluctuations in the flow ratio of the branch road to the arterial road. So, in order to adapt the signal timing to this kind of intersection, an optimization control algorithm based on fuzzy control and nonlinear programming (FCNP) was proposed. To verify this optimization algorithm, the Python and Vissim joint simulation was employed. Prior to the simulation, traffic flow data were collected in 12 consecutive hours at an arterial‐branch intersection in China. The simulation results show that, after signal timing optimization with FCNP, the average vehicle queue length and delay reduced 25.8% and 17.3%, respectively, when compared with the performance of the traffic‐actuated control, which also outperformed previous equivalent research. Besides, the overall operation of the intersection was verified to be greatly improved and stabilized by using the proposed algorithm. The findings of this study provide a reasonable solution of distributing the right‐of‐way at arterial‐branch intersections and suggest the advantage of combining fuzzy control and nonlinear programming in dealing with the signal timing optimization. [ABSTRACT FROM AUTHOR]

In order to address the problems of low energy storage capacity and short battery life in electric vehicles, in this paper, a new electromechanical-hydraulic power coupling drive system is proposed, and an electromechanical-hydraulic power coupling electric vehicle is proposed based on this system. The system realizes the mutual conversion between mechanical energy, hydraulic energy, and electric energy through the electromechanical–hydraulic coupler. This paper describes the structural characteristics and working principles of the system and analyzes the different working modes during the driving of the vehicle. We established a mathematical model of the hydraulic accumulator and the hydraulic pump and motor. Based on the vehicle dynamics model, an AME Sim vehicle model was built and the vehicle, and the relevant hydraulic parameters were set in combination with the actual situation. The braking energy recovery and release process was jointly simulated by AME Sim and Simulink. The simulation results show that the hydraulic accumulator size of the accumulator volume can influence the maximum working pressure of the accumulator and the SOC of the vehicle battery, and it is verified that 35 L is the best capacity. This study has an important reference value for matching electromechanical–hydraulic coupling parameters of electric vehicles. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)