The pressure signal of the piston motor is an important signal source of the hydraulic system,which changes the characteristics of pressure pulsation and reflects the local or global operation of the system state.In order to separate the component of pressure pulsation from the multi-component pressure signal and reconstruct its time domain feature,an extraction method of time-domain feature based on EEMD and wavelet packet decomposition is proposed.Firstly,the pressure signal and the interference signal are separated by EEMD.Secondly,according to the time-frequency characteristics of the pressure fluctuation of the piston pump and the piston motor,the pressure pulsation signal of the piston motor is obtained by wavelet packet decomposition and reconstruction,and the time-domain characteristics are extracted.Finally,combined with the experiment,the change regulation of the pulsating characteristic with the working condition is analyzed.The effectiveness of the proposed method is validated by the experiment,and the results show that:the amplitude of pressure pulsation decreases with increased speed,but increases with the increase of pressure,which is consistent with the mechanism of pressure fluctuation.The research achievement provides support for the operation condition monitoring of the piston motor.

Rare earth magnetostrictive transducer was a power to be able to convert electrical energy into sound energy.Terfenol-D bar was the driving force of the magnetostrictive transducer,it would produce a continuous axial vibration excitation by a magnetic field,thus promoting the radiant panel radiated sound field to a resonant cavity.Analyzed Terfenol-D bar by applying finite element software ATILA modal and harmonic response analysis module.Emphasis on the effects of Terfenol-D bar aspect ratio,excitation current and prestressed on the output characteristics(the frequency and the amplitude value when the magnetic rod in the piston modes).The results show that:magnetostrictive transducer may be due to demand conditions,select a different aspect ratio of Terfenol-D bar to reached the desired axial displacement of the output;output axial displacement Terfenol-D bar increased with external excitation current gradually;when the excitation current is constant,the appropriate size of prestressing can effectively increase the axial displacement output of the Terfenol-D bar,but too much will affect the prestressing Terfenol-D bar axial displacement output.

In the selective laser sintering process,the powdering efficiency and the powder density will directly affect the forming efficiency and molding quality of the molded parts.In order to improve the quality of powder,the powder device was analyzed and compared,and a new powder distribution scheme was put forward.Firstly,the structure of the powdering device is improved,and the kinetic analysis of the modified powder coating device is carried out.the force model of the powder particles under the action of powder was established.Then,based on the theoretical analysis of the model,the main parameters affecting the quality of the powder are the radius,roughness,rotation direction of the laying powder and the translation speed of the scraper and the laying roll.Finally the laser sintering equipment after the improvement of the powder coating device is used to study the experiment design.The results show that the improved powder coating device has a better effect on the molding quality of the molded parts,and it is concluded that with the increase of the roll speed,the dimensional accuracy of the molded piece will increase first and then decrease.

The time required by an optimal exact algorithm to solve the large-scale rectangle two-dimensional cutting problems may become unbearable.So an algorithm for two-stage homogeneous strip patterns for pieces is presented.The algorithm not only is appropriate for the shearing and punching process,but also reasonable in time.Firstly,vertical cuts divide the stock sheet into composite strips,and then horizontal cuts divide the composite strips into homogeneous strips.The algorithm uses a dynamic programming recursion to determine the optimal homogeneous strip layout,solves knapsack problems to obtain the homogeneous strip layout on the composite and the composite strip layout on the sheet.The algorithm is tested through benchmark problems,and compares with three famous algorithms,the classic two-stage algorithm,the TABU500 algorithm and optimal algorithm.The pattern value of this algorithm is better than that of the classic two-stage and TABU500 algorithm.What’s more,this algorithm can give solutions very close to optimal algorithm,and the computation time is shorter than optimal algorithm.

In order to improve the machine tool accuracy,a new modeling method of CNC machine tool thermal error which is based on the Kalman Filter is presented.Regard the regression coefficient of statistic model as a state vector,take the statistic model for the observation equation,and the statistic model has been realized by using the Kalman Filter method.Compared with the least squares,the Kalman method which is the least linear estimator of variance can be obtained the higher accuracy.The changing temperature of the spindle and the heat deformation is measured at the same time by using the transducer on the CNC machine tool.The model of Kalman filter is compared with the model of the least squares and the LS-SVM method.It shows that the accuracy of Kalman filter model is 10.5 % and 1.8 % higher than the LS and LS-SVM model.Moreover,the modeling time of Kalman method is 0.9 % and 6.8 % less than the modeling time of LS and LS-SVM method.

When the disk of tie-bolted fastened rotor contact each other,the thermal contact resistance between the disk contact surfaces play a critical role in heat transfer and the distribution of temperature field.On the basis of the surface fractal characteristics,combining Mandelbrot-Tian(M-T) fractal network model and the classical conduction theory,the Cantor set,which is not dependent on the observation scale,is chosen to obtain the pressure and heat transfer coefficient of the relationship between contact surfaces.The condition of rotor transient temperature field distribution are obtained through determining the contact thermal resistance.Analysis found that the thermal conductivity caused by the pre-tightening force has a little influence on the transient temperature field,when the rotor dynamics analysis can ignore the influence of the transient temperature field.

In view of the high precision requirement of the 3D printer of denture and the limitation of the traditional extrusion molding equipment,a design scheme for the special extrusion system for 3D printer is proposed.SolidWorks Motion is used to simulate the movement of the key components of the system to verify whether it can meet the requirements of motion continuity and ensure the continuity of the discharge from the motion continuity.According to the mechanics theory calculation and the ANSYS FLUENT software fluid simulation,the key components are analyzed to verify the rationality of the design scheme and parameters.Finally,the feasibility and accuracy of the system are further verified by the prototype experiment.The results show that the motion of the key components conforms to the required motion characteristics,and the rationality of the design parameters and the feasibility of the scheme can also be confirmed,which lays the foundation for the later research on the control algorithm for the extrusion system.

The LEBUS double-broken-line-groove winding systems are widely used in large tonnage winch drums which are safe and secure and can prolong the service life of the steel rope.In order to solve the batch processing problems of LEBUS grooves,a practical numerical control system for processing LEBUS grooves was designed in the paper which can be matched with the NC transformation of the old universal lathes.The design process of the numerical control system of the engine lathe for processing LEBUS grooves was discussed in detail,including the selection of the CPU chip,the expanding design of the memory,the expanding design of I/O interface,the expanding design of the keyboard and LED displaying interface and the expanding design of D/A interface.And the design idea of LEBUS grooves processing software was also given.The system has high control precision,simple structure,convenient operation,high ratio of performance to price and has certain popularization and application value.

Based on the requirement of food texture detection and quality evaluation,and the detection and evaluation of denture materials,a bionic chewing 6PSS parallel driven platform was designed.The basic structure of the parallel driven platform is introduced.The kinetic energy,potential energy and kinetic equation of the system are obtained by Lagrange method for dynamic modeling and analysis.The virtual prototype is established in Adams and kinematics simulation was carried out.A set of masticatory movement trajectory was given to the moving platform to simulate the right side of chewing food.The pose parameter curve of the moving platform was obtained.The parametric curve data of the moving platform centroid is taken as the input conditions of the dynamic equation,the generalized force of the system is solved and the dynamics simulation is carried out.The pose curve obtained by the simulation is compared with that obtained by the kinematic simulation,which verifies the correctness of the dynamic model and the bionics performance of the mechanism is proved.At the same time,the error between the two curves and the possible causes of the error are analyzed,which provides a reference for the subsequent control and optimization.

Selective Compliance Assembly Robot Arm (SCARA) runs fast with high repeated positioning precision in the horizontal plane.So adopts the method of modal analysis and topology optimization,in order optimizing the mechanical structure and reducing the weight of the SCARA robot.First,the SCARA robot arm was created with Solidworks software,then transmitted into finite element analysis software ANSYS Workbench for static analysis and modal analysis—as a result of the analysis,the first six order natural frequencies and vibration modes were obtained.Thirdly,to come up with the optimization direction of removing the arm’s material,the topology optimization method was used,and in the help with this method,the optimal structure of the arm was redesigned and the modal parameters of the optimized structure were calculated.Finally,by comparing the results from modal parameters before and after optimization, proved the fact that the optimized structure do well in reducing the arm’s weight and improving the arm’s mechanical properties.

The automobile electric seat memory box need to determine the status of the work by the sound interval of the buzzer before they leave the factory,ear recognition often misjudge the missing problem due to the interference of external environment.In order to solve this problem,the computer is used to collect the sound of the buzzer,and voice is detected by using dynamic variable window length with double threshold endpoint.The short-time energy with MFCC coefficient as the sound characteristic parameters are extracted into the improved DTW algorithm and template matching.Experimental results show that the system can identify the target sound and have good robustness under the condition of noise.

Liquefied Petroleum Gas(LPG),as a fuel,is easy to evaporate and also is convenient to be stored and carried.In this study,LPG is selected as the fuel of a two-stroke direct injection engine which is used as the power source of a light electric vehicle.The mixture formation process of the engine is numerically calculated using a CFD software Fire V2011.The injection timings at different running conditions are optimized at the first,then the evolution of the velocity and concentration fields during the process of mixture formation under typical conditions are analyzed.The results show that the fuel can be locked in cylinder at the timings of intake port closing(73 ℃A ABDC)and finally homogenous theoretical mixture can be formed at spark timings for all the calculated cases,including both warming condition(2 000 r/min) and electricity generation conditions(4 800 and 6 000 r/min).

The steering movement characteristic of buggy ladle was analysed,and the formula of rotation angles for each wheel as buggy ladle turned were derived based on the theory of vehicle steering.The minimum error between practical and theoretical rotation angle was treated as optimization objective,then the optimization mathematical model of steering mechanism of multi-axis vehicle was established.The typical steering mechanism of six-axis buggy ladle was analysed using simulation and optimization software,and the results showed that the coordination of wheel group was improved greatly after optimizing although that has problems before optimizing.

According to the structure characteristics of articulated dump truck,a model of 7 degrees of freedom was built.Based on the non-linear stiffness theory,the differential motion equations of the suspension system model were built.The vehicle system dynamics analysis model and the road model in time domain were built based on Simulink.The time domain characteristics of the vertical acceleration of the front and rear suspension were analyzed.The results showed that the vehicle loaded operating condition,the front suspension system inherent characteristics without significant changes,indicating that the rubber spring stiffness has obvious non-linear characteristic,played a very good effect of vibration reduction.The damping effect of the rear rubber spring is limited,and there is a need for further optimization.The bench test verifies the non-linear model accuracy,which provides a reference for the further research and design.

A 450 t heavy-duty bridge crane in a steel plant often appears in the operation of wheel-rail contact abnormalities and the phenomenon of stripping off the surface of the wheel and rail.In order to explore the reasons,first detect the track on-site and found that there is a straightness deviation of the track center of J-K/10-1 crane beam.Maximum deviation is 34 mm.In order to explore the reasons of the stripping of the wheel and rail surface and the influence of the anomaly on the wheel-rail contact,the finite element method is used to analyze the wheel and rail under different load conditions and straightness anomalies.Summarizes the variation law of the contact stress distribution of wheel and rail with the increase of load,and analyzes the reason of stripping and detachment of wheel and rail surface.The analysis of the straightness anomaly shows that the inside of the wheel is gradually in contact with the outside of the track after the deviation of 10 mm in straightness.When the offset is 30 mm,the contact pressure is increased by 31.39 % from 525.54 MPa,which is the main reason for the wheel side wear.

Using the platform of ANSYS Workbench response surface optimization and Six Sigma reliability analysis,based on the static analysis of the motorized spindle,the optimization design of the reliability is carried out with the quality as the optimization state variable and the maximum deformation as the optimization objective;The geometric dimension,external load,elastic modulus and front and rear bearing stiffness of the spindle are chosen as random input variables,and the reliability analysis of the motorized spindle is carried out.The results show that the optimized static stiffness of the spindle increases by19.44 %,which can satisfy the design standard value.The reliability sensitivity analysis shows that the random changes of Young’s modulus,external load,bearing stiffness of the front axle and inner circular hole radius have a greater influence on the static stiffness of the motorized spindle.Which shows that the structure reliability is higher and the reliability of the optimized motorized spindle is 98.459 %.

Green manufacturing is not only a modern manufacturing mode which considers the environmental impact and resource efficiency,but also an important guarantee for the sustainable development of manufacturing industry.The reasonable selection of cutter is the key to improve the green performance of cutting.Based on the concept of green manufacturing,the cutter selection evaluation system and the mathematical model are established with the processing time T,the processing quality Q,the processing cost C,the resource consumption R and the environmental impact E as the index.The model is solved by triangular fuzzy analytic hierarchy process and grey relational analysis method.Combined with an case of the optimization selection of the cutter which is used in an enterprise elevator parts iron core cutting process,the method can reasonably and effectively solve the problem of cutter selection.

The tool coatings have been widely applied in machining field and their evaluation methods are being gain more attention.Existing evaluation methods for tool coating characterization such as the microhardness,scratch and indentation test can simulate the failure behaviors under static loads.However,these methods are hard to characterize the tool coating performances such as impact resistance under dynamic forces caused by impact loads.In this paper,TiN tool coatings were repeatedly impacted using a specially designed impact tester driven by piezoelectric actuator.Experimentation and analysis concerning failure mechanism and repeated impact resistance were presented.Coating fracture initiation and propagation mechanism for TiN tool coatings under repeatedly impact test were studied.Experimental results indicate that the failure mechanism transform from cohesive failure to adhesive failure with the increase of impact cycles.The fracture initiation of TiN tool coatings can be characterized by oxidation wear and the fracture propagation rate can be evaluated by failed area ratio.The results of this research provide the characterization of tool coating performance and detailed explanation for failure mechanism with repeated impact loadings,which can be applied to the optimization of the tool coating materials and the strengthening coating performance evaluation with micro-blasted post treatment.

Here is a cross orthogonal ceramic parts composed of three sections of SiC ceramic pipe,two intersecting curved surfaces are formed at the both ends of the parts.The design requirements need to meet precision fit and achieve sealing at the both intersecting curved surfaces by grinding.To ensure the quality of grinding process and to meet precision fit and the sealing technology requirements at the both intersecting curved surfaces.In present work,design and manufacture of cross-intersectional ceramic pipes had been systematically investigated.Lapping finishing technics of pipe intersection line also had been discussed.Special clamp tool and differential screw fine-tuning mechanism were designed and fabricated in order to reach the required sealability.The results showed that accuracy and quality of crossed ceramic pipe met the accepted engineering requirement after lapping process.

The traditional defect detection system usually has one offline function,which sends an alarm when the cable diameter exceeds its standard value.A new online defect detection system has been developed.First,designing functions in this new defect detection system,such as dynamic display of the cable diameter datum,review of detection results,remote access and monitoring.Second,determine the connection mode of the system hardware.At last,build software framework.During the datum processing,linear interpolation has been used to connect the diameter and the location in the cable,and integral amplification algorithm has been used to detect the defect of fiber diameter.Besides,the error of cable diameter position’s estimation has been analyzed,which provides some help in setting the information of data acquisition card.The new defect detection system in this paper has been proved running successfully and efficiently.

There may be missing workpiece and other defects when circular workpieces are packed.To ensure the quality,need to check the number of workpieces in the box.A new auto counting system based on Faster-RCNN is proposed to save labor cost.To handle the problem that the workpiece may be undetected when be sheltered by something,a newly fragmentation training method is proposed.After that,it merges the sub-proposal by horizontal projection and vertical projection and clustering the centroid of the sub-proposals when testing.Realistic experiments prove that the method improves detecting efficiency as well as ensuring very high reliability and compatibility.

According to the structural characteristics of gantry crane,the parametric finite element model of gantry crane is built based on ANSYS APDL.To get the gantry crane maximum equivalent stress and deformation distribution of dangerous conditions,its finite element model is analyzed in both dangerous conditions.On the basis of this analysis,the section size and shape size,which have a great influence on the volume,are obtained through the sensitivity analysis of gantry crane structure.Under the condition of meeting the stiffness and strength requirements,the size of gantry crane is optimized with the use of sub-problem inside ANSYS algorithm.The optimization effect is obvious and the weight of the gantry crane is greatly reduced by 19.3 %.

Besides causing a high mortality rate,the traditional method of releasing fish fry has a low level of safety and comfort.A new releasing device was thus designed based on ergonomic principles.In order to verify the rationality and superiority of releasing device,used ergonomics software DELMIA to simulate the process of releasing and tested the muscle fatigue of the testers.Contrast the results of software simulation and muscle fatigue test between the releasing device and the traditional one,the releasing device is more reasonable and reliable.

The driving system of hydraulic chassis of high-speed rice transplanter is designed.Under the premise of ensuring work quality,the designed chassis adopt whole hydraulic driving system in order to change speed continuously,enhance power density,and improve layout flexibility.This chassis also can provide a platform of intelligence and automation.The close cycle system of single pump and four motors is designed in the driving system.The flow divider valve is used to prevent slipping.The slip rate measurement in paddy field is conducted for the more precise calculation results.The kinds of hydraulic pumps and motors are selected according to the calculated pressure,flux and displacement for ensuring that the pump works in its efficient speed range.The project has some significance for designing hydraulic chassis of other machineries.

In order to make the products meet the market and customer demand,this around design method of combining the target patent information with the functional requirements of the product is proposed.Firstly,the claim of the patent in the target document is decomposed,and the function structure model is established.And the product market and customer demand is investigated.Secondly,according to the function ontology knowledge base,the function requirement and the function of the original patent product model are compared.If two kinds of contrast functions belong to the same category,the contrast function in the original function model is replaced by the function requirement;conversely,the demand function is added to the original function model.And then realize function reconstruction.Finally,the feasibility of this method was verified by a rotation type femoral head neck external guidance and internal fixation configuration device.

The domestic and foreign remanufacturing laws and regulations are reviewed,especially parts remanufacturing which is involved in the recycling of End-of-Life Vehicle (ELVs).Makes a systematic exposition and comparative analysis from the aspects of policies and regulations,standards and regulations for the management of market,which provide experience and suggestions for our country’s ELV recycling and auto parts remanufacturing.