China Mechanical Engineering

Fractional-order Feedback Control Method for PMLSMs Based on Closed-loop Identification Model

ZHONG Yongbin, GAO Jian, FENG Fuyuan, ZHANG Lanyu,

2023, 34(23): 2773-2780，2793. DOI: 10.3969/j.issn.1004-132X.2023.23.001

Asbtract ( )

PDF (7146KB) ( )

References | Related Articles | Metrics

In order to improve the tracking accuracy of PMLSMs， a fractional-order feedback control method was proposed based on closed-loop identification model. By precisely adjusting the error amplitude characteristics of the feedback control system in a specific fractional-order form， the following errors of PMLSMs might be effectively suppressed. A closed-loop identification model was derived for the PMLSM and the parameter selection method of the fractional-order lead-lag compensator was determined based on analysis of the error amplitude characteristics. With the properly defined fractional-order parameters， the fractional-order feedback control system might accurately describe the frequency-domain characteristics of the PMLSM， and the identification accuracy and control performance of the PMLSM might thus be improved. The proposed method was experimentally validated on a PMLSM gantry motion platform through identification methods, tracking experiments with different motion planning, and circular trajectory motion experiments. The experiments on system closed-loop identification and motion tracking with different plannings were performed. The experimental results show that the closed-loop identification method may effectively suppress the influences of external interferences on the identification signals， and the closed-loop identification model is accurate for the control system， the proposed fractional-order feedback control method may greatly reduce the tracking errors of the PMLSMs， and compared to the PID control method， the proposed control method may reduce the root mean square error (RMSE) tracking errors by at least 82.47% under different motion scenarios. The experimental results demonstrate the effectiveness of the proposed method in improving the tracking accuracy of PMLSMs.

Failure Mode and Progressive Damage Analyses of Carbon-glass Hybrid Composite Single Nail and Single Shear Bolted Joints

ZHU Fuxian, QIU Gang, ZHU Xingmin, XU Xianyi, ZHOU Jinyu

2023, 34(23): 2781-2793. DOI: 10.3969/j.issn.1004-132X.2023.23.002

Asbtract ( )

PDF (27531KB) ( )

References | Related Articles | Metrics

The failure load, failure mode, and progressive damage processes of carbon-glass hybrid composite bolted connection structures were studied by using the method of experiments and numerical simulations. Based on the ABAQUS platform, the finite element models of 36 different types of connection structures with various width to diameter ratios(W/D) and end to diameter ratios(E/D) were established. According to the three-dimensional Hashin failure criterion and Chang-Chang failure criterion, the effects of structural dimensions E/D and W/D on the failure load and failure mode were analyzed, combined with the findings of the tensile tests. The impacts of E/D and W/D on the failure load and failure mode of the connection structures and the progressive damage processes of the connection structures under various failure modes were discussed. The results show that the failure modes of the carbon-glass hybrid composite bolted connection structures with a specific hybrid ratio include bearing failure, shear-bearing failure, and tensile failure. The structural dimensions E/D and W/D have a greater impact on the failure load and failure mode. The bearing failure mode of the connection structures is that the matrix of the laminated plates are damaged at the axis position on the extruding side of the bolt holes, and the failure extends outward in a sector shape along the axis to the structure failure. The shear-bearing failure mode is that a large number of fiber and matrix tensile damage occur from the bolt holes to the end face of the laminated plates, with the matrix bearing damage at the compression side of the bolt holes, generating a notch to the structural failure. The tensile failure mode is that the fiber and matrix tensile damage occurs at the upper and lower positions of the bolt holes of the laminates, and extends laterally to the upper and lower sides of the laminates, resulting in structural failure.

Cause Analysis on Multi-point Contact between Steel Ball and Raceway of Four-point Contact Ball Bearings

WANG Yatao, QIU Ming, ZHANG Jiaming, WANG Huijie

2023, 34(23): 2794-2804. DOI: 10.3969/j.issn.1004-132X.2023.23.003

Asbtract ( )

PDF (10503KB) ( )

References | Related Articles | Metrics

Aiming at the problems of premature bearing failure caused by multi-point contacts between the steel ball and the raceway of four-point contact ball bearings， taking QJ214 four-point contact ball bearings as the research object， the ball and the raceway contact models were established， and the causes of multi-point contacts between the ball and the raceway were analyzed when the structural parameters and working condition parameters were changed. The results show that with the increase of the coefficient of inner and outer raceway groove curvature radius or the thickness of inner and outer gasket， the contact state between the ball and the raceway may be changed from three-point contact to two-point contact， and then to three-point contact. At constant speed condition， with the reduction of axial load， the contact state between the ball and the raceway may be changed from two-point contact to three-point contact. When the rotational speed and the axial load are constant， the increase of radial loads may make the contact state of some steel balls and the raceway change from two-point contact to three-point contact， and then to four-point contact. The research findings may provide reference for avoiding the cats eye ring wear failure caused by multi-point contact during the running of four-point contact ball bearings.

Design and Processing Research of Dynamic Pressure Assisted Non-Newtonian Fluid Polishing Tools

ZHANG Qicong, JIANG Chen, YE Hui, SHEN Lingxin, JIAO Mengdie

2023, 34(23): 2805-2811，2823. DOI: 10.3969/j.issn.1004-132X.2023.23.004

Asbtract ( )

PDF (8987KB) ( )

References | Related Articles | Metrics

To overcome the problems of low and uneven material removal rate when polishing with NNFL, the design and processing research of dynamic pressure assisted non-Newtonian fluid polishing tools(DNNFTs) were carried out. The DNNFT was designed by adding the pressure-controllable center-int to form a dynamic pressure film. The mechanics properties of the filling material Silly-putty were analyzed, numerical simulation of NNFL fixed point polishing was carried out. The influences of liquid supply pressure on the dynamic pressure field, total pressure field and velocity field of liquid film in the processing area of DNNFT were analyzed based on FLUENT. The material removal function models were constructed based on Preston material removal principle. The polishing process experiments were carried out on 304 stainless steel workpieces. It is concluded that the material removal rate and uniformity may be effectively improved by adding the pressure-controllable center-int. The smallest value of surface roughness(Ra=19 nm) and the best material removal rate(2.431 mg/min) are obtained when the liquid pressure is as 0.8 MPa, the rotational speed is as 1200 r/min and the feed rate is as 6 mm/s. The results prove that DNNFT effectively improves the quality and efficiency of polishing, and improves the uniformity of material removal.

Research on Influences of Tooth Friction and Geometric Eccentricity Errors on Mesh Stiffness of Profile Shifted Spur Gear Pairs

HAO Zhuangzhuang, ZHANG Qingchun, HU Yunbo, GUO Yibin, WANG Donghua, LI Wanyou

2023, 34(23): 2812-2823. DOI: 10.3969/j.issn.1004-132X.2023.23.005

Asbtract ( )

PDF (12063KB) ( )

References | Related Articles | Metrics

Taking the involute spur gear pairs with profile shift as the research object， the mesh stiffness calculation models including nonlinear Hertzian contact stiffness， tooth profile curve， fillet foundation stiffness with structure coupling effect were established based on the potential energy method. Considering the influences of gear profile shifts， the calculation formulas for tooth profile curve， half tooth angle of base circle and half tooth angle of dedendum circle in mesh stiffness calculation were revised. The fillet foundation stiffness models were revised by considering tooth surface frictions. The pressure angle models of gear mesh point were derived by considering geometric eccentricity errors. The effects of profile shifted， tooth surface frictions and geometric eccentricity errors on mesh stiffness were studied. The results show that the center distance， stiffness amplitude and contact ratio of the profile shifted gear pairs have great changes. Owing to the profile shift， the moment when the direction of frictional force changes on a pair of meshing gears no longer occurs within the single tooth meshing interval， thereby affecting the characteristics of the mesh stiffness. Geometric eccentricity increases the peak-to-peak values of the mesh stiffness， and at the same time， sideband frequencies with intervals corresponding to the rotational frequencies appear in the frequency domain of the meshing stiffness. In the presence of eccentricity errors in both the driving and driven gears， a new sideband frequency arises with an interval equal to the difference in rotation frequency. Considering the combined effects of three factors， the mesh stiffness characteristics may be significantly influenced. The research results provide the references for further researches of the dynamics of profile shifted gears.

Flow Field Design and Experimental Research of ECM of Array Spherical Groove Structures with Variable Cross-sections

YAN Dinghu, ZHAO Jianshe, ZHANG Changhao, GAO Weizheng, ZHU Yin,

2023, 34(23): 2824-2831. DOI: 10.3969/j.issn.1004-132X.2023.23.006

Asbtract ( )

PDF (10544KB) ( )

References | Related Articles | Metrics

Variable cross-section spherical groove structure had high surface hardness and complex 3D shape. ECM had better technical and economic advantages， but the processing accuracy and processing stability were affected by the flow field obviously. In order to improve the uniformity of the electrolyte flow field， the influences of the electrolyte flow mode and channel structure on the flow field distribution were discussed based on the flow field simulation analysis， and the ECM experiments were carried out. The simulation and test results show that the zonal liquid flow in directional channel is conducive to improving the stability of the flow field and the consistency of the flow rate distribution， which may improve the processing stability. Optimization of the inlet and outlet flow channel structures may further improve the surface quality of the spherical groove， which may meet the requirements of machining stability and machining accuracy.

Dynamics Simulation Data Driven Domain Adaptive Intelligent Fault Diagnosis

YU Shubo, LIU Zhansheng, ZHAO Chen

2023, 34(23): 2832-2841. DOI: 10.3969/j.issn.1004-132X.2023.23.007

Asbtract ( )

PDF (7710KB) ( )

References | Related Articles | Metrics

High-quality labeled data was a crucial prerequisite for the effectiveness of deep learning-based fault diagnosis methods. However， obtaining a substantial number of industrial labeled fault cases was challenging， which led the models generalization ability weak. A novel domain adaptive intelligent diagnosis method driven by dynamics simulation data was proposed to address the above issue. This method considered the fundamental disparity between simulation data and actual data， and introduced a feature separation network for domain adaptation in diagnostic modeling. Based upon traditional domain adaptation models， a unique feature extractor that was specific to the target domain was incorporated to explicitly separate environmental noises present in actual data. This enhancement improved fault feature representation and clustering capabilities through other features that remain invariant across domains. Furthermore， a novel training strategy was proposed that leveraged diagnostic results obtained from the shared feature extractor to iteratively update the model parameters of the unique feature extractor， thereby enhancing training stability even further. The proposed method was evaluated using the bearing dataset from Case Western Reserve University， demonstrating improved feature extraction and clustering capabilities compared to other transfer methods for comparison， as evidenced by enhanced performance and diagnostic accuracy. Additionally， the hyper-parameter sensitivity was analyzed empirically.

Optimization of Process Parameters in Process Manufacturing Based on Ensemble Learning and Improved Particle Swarm Optimization Algorithm

LIU Xiaobao, YAN Qingxiu, YI Bin, YAO Tingqiang, GU Wenjuan

2023, 34(23): 2842-2853. DOI: 10.3969/j.issn.1004-132X.2023.23.008

Asbtract ( )

PDF (12172KB) ( )

References | Related Articles | Metrics

Considering the complexity of technological processes， the serious coupling between multiple processes and the difficulties in optimizing process parameters during the process manufacturing， a multi-process technological parameter fusion optimization method was proposed based on LSTM neural network， XGBoost algorithm and IPSO algorithm. A data preprocessing model was established based on LSTM neural network， and the time series characteristics of processing data were extracted through LSTM neural network， which realized the processing of outlier in process data. And a PSO-XGBoost quality prediction model was constructed by fitting the nonlinear relationship between processing parameters and quality indexes with XGBoost and combining with particle swarm optimization algorithm. Then the output of the quality prediction model was taken as the fitness， and the improved particle swarm algorithm was used for trolling the global optimal processing parameters， which realized the fusion optimization of the quality of process manufacturing. A process production line of an enterprise was taken as an example to verify the effectiveness of the multi-process technological parameter fusion optimization model.

Centrifugal Pump Fault Diagnosis Methods Based on Dislocation Superposition Methods and Improved Probabilistic Neural Networks

CHEN Jian, XU Chang, XU Tingliang,

2023, 34(23): 2854-2861. DOI: 10.3969/j.issn.1004-132X.2023.23.009

Asbtract ( )

PDF (6256KB) ( )

References | Related Articles | Metrics

Based on dislocation superposition method and improved probabilistic neural network， a fault diagnosis method of centrifugal pumps was proposed to solve the problems of online fault diagnosis using acoustic radiation signals of centrifugal pumps under strong background noise. Firstly， the acoustic radiation signals of centrifugal pumps were denoised by dislocation superposition method to enhance the fault information in acoustic radiation signals and improve the signal-to-noise ratio. The time domain features of acoustic signals were extracted to construct the time domain feature matrix. After dimensionality reduction of the obtained time domain feature matrix through principal component analysis， which was used as the inputs of machine learning probabilistic neural network. At the same time， Harris hawk optimization algorithm was used to optimize the parameters of the probabilistic neural network to get the diagnosis model， and then the improved probabilistic neural network was used to recognize the patterns of the centrifugal pump faults， and compared with a variety of diagnostic methods. The experimental results show that the dislocation superposition method may highlight the signal characteristics and realize signal enhancement， and the improved probabilistic neural network has a good ability of online fault diagnosis of centrifugal pump acoustic radiation signals.

Study on Surface Integrity in milling of TC11 Titanium Impellers

WU Zegang, HOU Yongfeng, MIAO Qing, LI Jing, ZHANG Dinghua, LUO Ming,

2023, 34(23): 2862-2872. DOI: 10.3969/j.issn.1004-132X.2023.23.010

Asbtract ( )

PDF (11094KB) ( )

References | Related Articles | Metrics

Based on the real machining parameters， this paper investigated the effects of milling speed， feed per tooth， stepover， milling depth and coolant on the surface integrity of the integral impellers， which includes the aspects such as surface roughness， surface morphology， surface microhardness， microstructure and residual stress. The results show that stepover and feed per tooth have the most significant influence on the surface roughness， the smaller stepover and feed per tooth value result in smaller blade surface roughness. Specifically， when the stepover is decreased from 0.3 mm to 0.16 mm， the average roughness value reduces from 0.64 μm to 0.48 μm； as the feed per tooth is decreased from 0.1 mm to 0.06 mm， the average roughness value decreases from 0.62 μm to 0.4 μm. Both of the stepover and feed per tooth significantly impacts the surface morphology. As the stepover and feed per tooth increase， the row spacing residual height and feed residual height also increase. Since the selected machining parameters are relatively reasonable， blade surface is observed to be smooth without the production of defects such as scratches， scrapes， and burrs， etc. Moreover， under the reasonable machining parameters， the generated force and heat are insufficient to alter the surface microhardness， which fluctuates around 335HV for each machining parameters， leading to no distinct difference in the surface hardening layer compared to the substrate. The residual stresses observed are predominantly compressive stresses， with limited correlation to the stepover and milling depth. When considering the milling speed and feed per tooth， the surface compressive stress initially increases and
then decreases. Along the depth direction， compressive stress initially slightly decreases， reaches a peak， and finally stabilizes within the matrix. The maximum residual stress reaches to 275 MPa and 400 MPa in the parallel and perpendicular feed directions， respectively. Surface residual stress under the water-based coolant is much higher than that under the oil-based coolant， but decreases significantly in the depth direction.

Geometric State Comprehensive Control Method for Aerospace-oriented Thin-walled Conical Cylinders Roll-forming Processes

XIE Han, WANG Xiaokai, HAN Xinghui, HUA Lin, ZHANG Ke, ZHENG Gefei

2023, 34(23): 2873-2880. DOI: 10.3969/j.issn.1004-132X.2023.23.011

Asbtract ( )

PDF (15727KB) ( )

References | Related Articles | Metrics

In order to solve the problems of difficult control of geometric deformations in roll-forming processes of aerospace thin-walled conical cylinders， three typical abnormal deformation states and formation mechanism of thin-walled conical cylinders were revealed， such as axis deviation， axis tilt and small end retraction. A conical roller motion coordination control method was proposed based on linear velocity feedback of cylinders， and a conical roller motion control model was established. The billet optimization design methods of thin-walled conical cylinders were proposed， and the corresponding core roll inclined feed control strategies were established， which ensured the consistency of the diameter growth rate of conical cylinders and eliminated the small end shrinkage phenomenon caused by the mismatch between the axial and circumferential flows of metal. The finite element models of thin-walled conical cylinder rolling with improved control methods and strategies were established based on ABAQUS software and VUAMP subroutine development. The forming effect of the cone rolling processes under conventional planning control， independent control and comprehensive control was compared and analyzed. The results show that the indexes such as axis offset， roundness error， concentricity error and inclination angle error of cylinder using the comprehensive control method are reduced by 93.6%， 75.3%， 95.1% and 97.2% in the modulation stage， respectively， compared with the conventional planning control.

Compensation and Correction Method of Compound Tire Pressure Monitoring Considering Influences of Tire Load Transfer

TANG Xianzhi, ZHANG Xiaozhuang, HAO Shaopeng, WANG Bo, ZHANG Yu

2023, 34(23): 2881-2888. DOI: 10.3969/j.issn.1004-132X.2023.23.012

Asbtract ( )

PDF (6683KB) ( )

References | Related Articles | Metrics

The vehicle would produce load transfer during acceleration and hill climbing， which led to the interference of tire pressure monitoring results. To address this problem， a tire pressure monitoring result compensation correction method was proposed based on tire loads herein. Dual estimation of vehicle mass and center of mass position was carried out based on Dual-UKF， and recursive least square (RLS) was used for slope identification. The data of load， vehicle speed， tire pressure and tire sinkage were collected by using a tire rotation hub test bench. The relational expression of load, speed, tire pressure and tire sinking were obtained by fitting the data. Using slope identification， the four-wheel independent load was calculated by estimating the vehicle mass and center of mass position to correct the corresponding wheel speed pulse. The test results show that the calculated values of tire pressure without load correction have 20% stable error and large fluctuation. with load correction， although there is a certain hysteresis and fluctuation， it will eventually converge to the true value quickly and the stable error is within 5%， which solves the problem of inaccurate tire pressure estimation due to load changes.

Research on Active Power Control of Hydraulic Wind Turbines Based on Feedback Linearization and Nonlinear Disturbance Compensation

CHEN Lijuan, WU Die, GAO Wei, WEI Longzheng, CAO Shengwei, AI Chao, LI Jingbin

2023, 34(23): 2889-2897. DOI: 10.3969/j.issn.1004-132X.2023.23.013

Asbtract ( )

PDF (6922KB) ( )

References | Related Articles | Metrics

The hydraulic wind turbine could not directly generate electricity after being connected to the grid， it was necessary to control the active power. The wind energy had randomness and volatility. The system had time-varying and nonlinear characteristics， and it was necessary to solve the accurate control of the active power of the fans under external disturbances. The nonlinear problem of the hydraulic main drive system was solved by feedback linearization. The nonlinear disturbance observer was used to quickly and accurately observe the influences of external disturbances on the output power of the system. An active power compensation controller under mismatched disturbances was proposed to accurately compensate the influences of disturbances on the output power of the system， and the active power control strategies of the hydraulic wind turbine were obtained. Based on the semi-physical simulation experimental platform of 30 kV·A hydraulic wind turbine， the output active power of the unit may accurately follow the target speed changes. The absolute error of active power is as ±0.05 kW， and the steady-state errors are within the range of 3%～5%.

Table of Content