Search Results (62)

As a key component in the hydraulic brake system of automobiles, the brake joint directly affects the braking performance and driving safety of the vehicle. Therefore, improving the quality of brake joints is crucial. During the processing, due to the complexity of the welding material and welding process, the weld seam is prone to various defects such as cracks, pores, undercutting, and incomplete fusion, which can weaken the joint and even lead to product failure. Traditional weld seam detection methods include destructive testing and non-destructive testing; however, destructive testing has high costs and long cycles, and non-destructive testing, such as radiographic testing and ultrasonic testing, also have problems such as high consumable costs, slow detection speed, or high requirements for operator experience. In response to these challenges, this article proposes a defect detection and classification method for laser welding seams of automotive brake joints based on machine vision inspection technology. Laser-welded automotive brake joints are subjected to weld defect detection and classification, and image processing algorithms are optimized to improve the accuracy of detection and failure analysis by utilizing the high efficiency, low cost, flexibility, and automation advantages of machine vision technology. This article first analyzes the common types of weld defects in laser welding of automotive brake joints, including craters, holes, and nibbling, and explores the causes and characteristics of these defects. Then, an image processing algorithm suitable for laser welding of automotive brake joints was studied, including pre-processing steps such as image smoothing, image enhancement, threshold segmentation, and morphological processing, to extract feature parameters of weld defects. On this basis, a welding seam defect detection and classification system based on the cascade classifier and AdaBoost algorithm was designed, and efficient recognition and classification of welding seam defects were achieved by training the cascade classifier. The results show that the system can accurately identify and distinguish pits, holes, and undercutting defects in welds, with an average classification accuracy of over 90%. The detection and recognition rate of pit defects reaches 100%, and the detection accuracy of undercutting defects is 92.6%. And the overall missed detection rate is less than 3%, with both the missed detection rate and false detection rate for pit defects being 0%. The average detection time for each image is 0.24 s, meeting the real-time requirements of industrial automation. Compared with infrared and ultrasonic detection methods, the proposed machine-vision-based detection system has significant advantages in detection speed, surface defect recognition accuracy, and industrial adaptability. This provides an efficient and accurate solution for laser welding defect detection of automotive brake joints. Full article

The hydraulic turbine serves as the cornerstone of hydropower generation systems, with the sealing system’s performance critically influencing energy conversion efficiency and operational cost-effectiveness. The sealing ring is a pivotal component, which mitigates leakage and energy loss by regulating flow within the narrow gap between itself and the frame. This study investigates the intricate flow dynamics within the gap between the sealing ring and the upper frame of a super-large-scale Francis turbine, with a specific focus on the rotating wall’s impact on the flow field. Employing theoretical modeling and three-dimensional transient computational fluid dynamics (CFD) simulations grounded in real turbine design parameters, the research reveals that the rotating wall significantly alters shear flow and vortex formation within the gap. Tangential velocity exhibits a nonlinear profile, accompanied by heightened turbulence intensity near the wall. The short flow channel height markedly shapes flow evolution, driving the axial velocity profile away from a conventional parabolic pattern. Further analysis of rotation-induced vortices and flow instabilities, supported by turbulence kinetic energy monitoring and spectral analysis, reveals the periodic nature of vortex shedding and pressure fluctuations. These findings elucidate the internal flow mechanisms of the sealing ring, offering a theoretical framework for analyzing flow in microscale gaps. Moreover, the resulting flow field data establishes a robust foundation for future studies on upper crown gap flow stability and sealing ring dynamics. Full article

Heating, ventilation, and air-conditioning systems account for 40–60% of the energy consumed in commercial buildings, and much of this load originates from sub-optimal piping layouts in chiller-plant rooms. This study presents an automated routing framework that couples Building Information Modeling (BIM) with an enhanced A* search to produce collision-free, low-resistance pipelines while simultaneously guiding component selection. The algorithm embeds protective buffer zones around equipment, reserves maintenance corridors through an attention-based cost term, and prioritizes 135° elbows to cut local losses. Generated paths are exported as Industry Foundation Classes (IFC) objects for validation in a BIM digital twin, where hydraulic feedback drives iterative reselection of high-efficiency devices—including magnetic-bearing chillers, cartridge filters and tilted-disc valves—until global pressure drop and life-cycle cost are minimized. In a full-scale shopping-mall retrofit, the method significantly reduces pipeline resistance and operating costs, confirming its effectiveness and replicability for sustainable chiller-plant design. Full article

As the core component of modern mechanical transmission, the precision rotary motion mechanism and its drive system have wide applications in aerospace, robotics, and other fields. This article systematically reviews the design principles, performance characteristics, and research progress of various rotational motion mechanisms and their driving technologies. The working principles, advantages, disadvantages, and applicable scenarios of gears, drive belts, sprockets, camshafts, ratchet claw mechanisms, and linkage mechanisms were analyzed in terms of traditional mechanisms. In terms of new mechanisms, we focused on exploring the innovative design and application potential of intermittent indexing mechanisms, magnetic gears, 3D-printed spherical gears, and multi-link mechanisms. In addition, the paper compared the performance differences of electric, hydraulic, pneumatic, and piezoelectric drive methods. Research has shown that through material innovation, structural optimization, and intelligent control, there is still significant room for improvement in the load capacity, accuracy, and reliability of precision rotary motion mechanisms, providing theoretical support and practical reference for innovative design and engineering applications of future mechanical transmission technologies. Full article

As a crucial component of the Beijing–Hangzhou Grand Canal’s hydraulic engineering, the Jiangnan Canal has historically played a pivotal role in China’s development as a key hydraulic infrastructure. This water conservancy project, connecting northern and southern water systems, not only facilitated regional economic integration but also nurtured unique cultural landscapes along its course. The Jiangnan Canal and its adjacent cities were selected as the study area to systematically investigate 334 tangible cultural heritage (TCH) sites and 420 intangible cultural heritage (ICH) elements. Through integrated Geographical Information System (GIS) spatial analyses—encompassing nearest neighbor index, kernel density estimation, standard deviation ellipse assessment, multi-ring buffer zoning, and Geodetector modeling, the spatiotemporal distribution features of cultural heritage were quantitatively characterized, with a focus on identifying the underlying driving factors shaping its spatial configuration. The analysis yields four main findings: (1) both TCH and ICH exhibit significant spatial clustering patterns across historical periods, with TCH distribution displaying an axis-core structure centered on the canal, whereas ICH evolved from dispersed to clustered configurations. (2) The center of gravity of TCH is primarily around Taihu Lake, while that of ICH is mainly on the south side of Taihu Lake, and the direction of distribution of both is consistent with the direction of the canal. (3) Multi-ring buffer analysis indicates that 77.2% of TCH and 49.8% of ICH clusters are concentrated within 0–10 km of the canal, demonstrating distinct spatial patterns: TCH exhibits a gradual canal-dependent density decrease with distance, whereas ICH reveals multifactorial spatial dynamics. (4) Human activity factors, particularly nighttime light intensity, are identified as predominant drivers of heritage distribution patterns, with natural environmental factors exerting comparatively weaker influence. These findings provide empirical support for developing differentiated conservation strategies for canal-related cultural heritage. The methodology offers replicable frameworks for analyzing heritage corridors in complex historical landscapes, contributing to both applied conservation practices and theoretical advancements in cultural geography. Full article

This paper presents a quasi-static model for assessing potential energy savings through partial electrification of a land leveler implement. The quasi-static model simulates the behavior of the hydraulic circuit components, including the pump and a spool-type flow divider, for a commercial land leveler used in agricultural applications. Two electrification schemes are presented. In the first scheme, the pump, originally driven at fixed speed by the PTO, is driven at variable speed by an electric drive, with no changes in the hydraulic circuit. In the second electrification scheme, the decentralization of the hydraulic system is implemented by using separate variable-speed pumps for each actuator. Results show significant potential energy savings of 9–22% with the first electrification scheme and 45–53% with the second scheme, compared to the traditional non-electrified setup. Our findings demonstrate that electrification could be a strategic choice to improve the efficiency of tractor implements and agricultural machinery. Full article

Elevators serve as essential vertical transportation systems for both passengers and heavy loads in modern buildings. Electromechanical lifts have become the dominant choice due to their performance advantages over hydraulic systems. A critical component of their drive mechanism is the Permanent Magnet Synchronous Motor (PMSM), which is subject to mechanical and electrical stress during continuous operation. This necessitates advanced monitoring techniques to ensure safety, system reliability, and reduced maintenance costs. In this study, a fault-tolerant PMSM is designed and evaluated through 2D Finite Element Analysis (FEA), optimizing key electromagnetic parameters. The design is validated through experimental testing on a real elevator setup, capturing operational data under various loading conditions. These signals are preprocessed and analyzed using advanced machine-learning techniques, specifically a Random Forest classifier, to distinguish between Normal, Marginal, and Critical states of motor health. The model achieved a classification accuracy of 94%, demonstrating high precision in predictive maintenance capabilities. The results confirm that integrating a fault-tolerant PMSM design with real-time data analytics offers a reliable solution for early fault detection, minimizing downtime and enhancing elevator safety. Full article

The practice of operating hydraulic machines and equipment shows that failures can occur earlier than the specified lifespan. At the same time, at the stage of carrying out strength calculations of the designed machines and equipment, significant safety margins are incorporated into parts and units. That is, calculated machine lifespans often exceed actual values. Accurate data require full-scale lifespan testing or observations of operation. However, resource tests are economically expensive, since they require a significant amount of energy, and, as a result, lead to a negative impact on the environment. It is possible to level out the listed shortcomings during resource tests by using energy-efficient and energy-saving technologies, such as energy recovery. This study enhances energy efficiency and assesses engineering systems during equipment design. In particular, we present a hydromechanical drive design for testing reciprocating hydraulic machines. The study analyzes energy-saving and energy recovery methods during operation. On the basis of the analysis and previously conducted studies, we developed a mathematical model for hydraulic equipment testing. The developed model is based on the volumetric stiffness theory, enabling analysis of the design and functional characteristics of test stand components on their dynamic behavior and energy efficiency. Full article

Direct injection of hydrogen at high pressures into an otherwise unmodified heavy-duty diesel engine offers a near-term pathway to near-zero greenhouse gas emissions for commercial vehicles. Hydrogen direct-injection engines maintain diesel-like performance with equal or better thermal efficiency. Supplying the hydrogen for injection pressures of ~30 MPa requires a high-pressure supply. Onboard hydrogen compression enables more complete utilization of the stored compressed hydrogen; however, it introduces a significant parasitic load on the engine. The magnitude of this load depends on factors such as the compressor’s configuration, capacity, pressure ratio, efficiency, and the engine’s operating conditions. This paper presents an exergy analysis of an onboard hydrogen compression system that uses hydraulically driven free-floating pistons, sized for heavy-duty commercial vehicles. Minimizing the parasitic loads from the compressor is essential to retain vehicle performance and maximize system-wide efficiency. The exergy analysis approach provides a comprehensive understanding of the whole compression system by comparably quantifying the losses across all components. A one-dimensional model of the compression system, developed in GT-SUITE^TM and validated with experimental data, is used to quantify the main exergy loss components. Exergy efficiency ranges from 12% to 45% under varying pressure ratios and cycle frequencies, with a pronounced increase in efficiency observed at higher cycle frequencies. Major exergy losses occur in the hydraulic driving system up to 79%, especially during retracting and idle phases for lower pressure ratios and cycle frequencies. Within the compression cylinder, exergy destructions account for less than 10% of the total work input, wherein heat transfer and piston friction are identified as the dominant contributors to exergy destruction, with their effects intensifying at higher pressure ratios. This work highlights the challenges of onboard gas compression and develops a systematic framework that can compare compressor design alternatives for different driving cycles. Full article

The electro-hydraulic servo valve is a critical component that transforms electrical signals into hydraulic signals, thereby controlling the hydraulic system. It finds extensive application in precision control systems. The stability of the electro-hydraulic servo valve is primarily influenced by the armature assembly. Unlike integral armature assembly, the separated armature assembly, comprising the armature, spring tube, flapper, and feedback spring, is joined through an interference fit, which introduces prestress within the assembly. The existence of prestress may affect the operational mode of the armature assembly. Consequently, this paper investigates the vibration characteristics of the separated armature assembly under interference fit conditions. Comparative analysis reveals that interference fit indeed generates prestress, which cannot be overlooked. To further validate the reliability of the simulation results, the natural frequency of the separated armature assembly is determined by applying a sweeping frequency signal to the torque motor using an electric drive, thereby verifying the feasibility of the simulation analysis. Additionally, the impact of interference on the vibration characteristics of the separated armature assembly is examined, confirming the accuracy of the simulation analysis method based on the interference fit. The research on vibration characteristics of a separated armature assembly provides technical support for the structural optimization design of the electro-hydraulic servo valve, thereby enhancing its performance. Full article

There are extensive areas of mugwort cultivation in China, making efficient harvesting crucial for the industry’s economic performance. However, the lack of specialized harvesting machinery for hilly and mountainous regions leads to reliance on manual operations, characterized by high labor intensity and low efficiency. To address these issues, a self-propelled mugwort harvester is designed based on mugwort planting patterns and the physical characteristics of mugwort during the harvesting period. Key structural components, such as drum dimensions, tooth shapes, and tine arrangements, are developed, and a defoliation force model is established to identify factors influencing the net rate of mugwort leaf harvesting, impurity rate, and mugwort leaf usability. The harvester employs a fully hydraulic drive system, for which the hydraulic system is designed and components are selected. A quadratic regression orthogonal rotary test determines the optimal parameters: a forward speed of 0.8 m/s, drum speed of 200 r/min, and cutting table height of 50 mm. Field tests show that the harvester achieves a net rate of mugwort leaf harvesting of 93.78%, an impurity rate of 13.96%, a mugwort leaf usability of 86.23%, and an operational efficiency of 0.155 hm²/h, while maintaining stable operation under field conditions. Beyond these performance metrics, the harvester reduces dependency on manual labor, lowers operational costs, and increases profitability for farmers. By improving the sustainability and mechanization of mugwort harvesting, this study provides an efficient solution for mugwort cultivation in hilly and mountainous regions and contributes to the sustainable development of the industry. Full article

Hydraulic motors have been widely used in large-scale machinery such as ground heavy equipment and heavy-duty vehicles, ships, and so on because of their high-power drive capability. However, the driving device is confronted with constraints related to its size and weight. Typically, the hydraulic axial piston motor is preferred for its simplicity and efficiency. However, the oil distributor in traditional hydraulic motors faces significant challenges, such as evident oil leakage and power loss from the mating surfaces of the fixed oil distributor and rotating cylinder block. To enhance the reliability and performance of hydraulic motors employed in paper driving applications, this paper introduces a digital radial hydraulic motor used for heavy-duty vehicle traction. The motor is powered by an on-board pump station from which several on/off valves can distribute the hydraulic oil. This design effectively mitigates the performance degradation issues associated with friction and wear in traditional hydraulic motor oil distributors. The drive characteristics of the motor can be flexibly adjusted through the combination of valves. Our investigation into the motor’s design principles and parameter analysis is poised to make an indirect yet significant contribution to the optimization of heavy-duty vehicle traction systems. This paper delineates the application conditions and operational principles of the digital hydraulic motor, thoroughly analyzes the intricate topological interrelationships of its parameters, and meticulously develops a detailed component-level model. Through comprehensive calculations, it reveals the impact of configuration and flow valve parameters on motor efficiency. A simulation model is established for the purpose of verification. Furthermore, the influence of the flow allocation method on efficiency and pressure pulsation is examined, leading to the proposal of a novel flow allocation strategy, the efficacy of which is substantiated through simulation. In conclusion, this paper formulates critical insights to inform the design and selection of components for digital hydraulic motors. These findings may provide a feasible solution for heavy-duty vehicle traction application scenarios. Full article

This paper presents the results of a study on the effects of low car speeds and the elastic-damping properties of tires on steering effort. “Steering effort” is a measure of the demand/energy consumption of the power steering system that limits the force applied by the driver to the steering wheel. Low driving speeds, on the other hand, are characteristic of urban traffic, where we would like to see as many electric cars moving as possible. An increase in “driver effort” means a higher electricity consumption and shorter car range. In this study, energy intensity was evaluated for a typical maneuver such as a double lane change. For this purpose, measurements were made of the torque on the steering wheel, the speed of the car, and the lateral accelerations acting on the car. A torque wheel, an optoelectronic sensor for measuring the components of the car’s motion, and an acceleration sensor were used for the study. The test subjects were two passenger cars with hydraulic power steering systems. The tests were carried out for four values of air pressure in the tires. This made it possible to determine four work charts for each wheel. The work charts made it possible to identify the stiffness and damping coefficients of the tires for the tested cars. The values of the coefficients were used to determine the correlation between the directional coefficient of the regression lines of the skeletal axes of the elastic and damping characteristics and the index determining steering effort. Full article

This paper introduces a control method tailored for the speed regulation of monorail cranes in coal mines. Initially, an analysis of the structure and load conditions of the monorail crane drive components is conducted to calculate the traction force, clamping force, and target travel speed across varying operational scenarios. Subsequently, the hydraulic system schematic of the monorail crane is analyzed to develop a mathematical model for speed control, enabling the assessment of system stability using transfer functions. A simulation model of the monorail crane speed control loop is then created in AMESim, where fuzzy adaptive PID controllers and MPC controllers are optimized in a collaborative simulation with Simulink. Experimental findings reveal that in a single acceleration condition, both controllers demonstrate superior dynamic response compared to a traditional PID controller, with the MPC controller exhibiting an overshoot of merely 8.9%. In speed variation conditions, the MPC controller achieved a settling time in the range of 0.26–0.3 s. Notably, the MPC controller displays a maximum overshoot of 11%, substantially enhancing the dynamic response performance of speed regulation in monorail cranes. Full article

The results of the first stage of work aimed at improving a hybrid drive system in which the combustion engine is supported by a pneumatic–hydraulic motor are presented. The purpose of the described work was to show that a heat exchanger with a design adapted to the operating conditions of a pneumatic–hydraulic motor would allow sufficient air heating at the expense of waste heat from the combustion engine, thus increasing the efficiency of the drive system. It was assumed that the key component of the heat exchanger would be copper foam in order to increase the heat exchange surface. A prototype modular heat exchanger was designed and tested. An open-cell copper foam with a porosity of 0.9 and a pore density of 40PPI was placed in the heat exchanger. Experimental and numerical air heating studies were carried out under various heat exchanger operating conditions. The tests were conducted at initial air temperatures of −123 °C, −71 °C, and 22 °C and air pressures of 2.5 × 10⁶ and 7.0 × 10⁶ Pa. The air mass flux was in the range of 3.6–1644 kg/(m²s). It was found that the tested heat exchanger allows a reduction in air consumption in the drive system of 11% to 58% and increases the efficiency of the air expansion system by 16% to 30%. The maximum efficiency of the heat exchanger is 96%. The results of the work carried out will help to improve the pneumatic–hydraulic drive systems of work machines and vehicles. Full article