Horizontal vibration response analysis of ultra-high-speed elevators by considering the effect of wind load on buildings

At present, the wind-induced vibration effects of super-high-rise buildings caused by wind loads can no longer be ignored. The wind-induced vibration effect of super-high-rise buildings will inevitably cause the vibration of ultra-high-speed elevators. However, for the study of the vibration characteristics of ultra-high-speed elevators, the wind-induced vibration effect of the ultra-high-speed elevator is often ignored. Based on Bernoulli–Euler theory, the forced vibration differential equation of elevator guide rail was established, and the vibration equation of elevator guide shoe and car was established by using the Darren Bell principle. The coupled vibration model of the guide rail, guide shoes, and car can be obtained through the relationship of force and relative displacement among these components. Based on the model, the effects of wind pressure and building height on the horizontal vibration of the ultra-high-speed guideway and passenger comfort were analyzed. The results showed that the influence of the wind load on the vibration of ultra-high-speed elevator can no longer be disregarded, and the maximum horizontal vibration acceleration of the guide rail is positively correlated with the height of building. The vibration acceleration of the same height rail increases with the increase in wind pressure. The vibration dose values (VDVs) increase with the increase in wind pressure and building height, respectively.

Straightness Detection Method and Accuracy Analysis of Guide Rail Parts

Guide rail is widely used in various machine tools. It mainly plays the role of guidance and support. The geometric accuracy of the guide rail, especially the straightness accuracy, directly affects the stability of the machine tool and the accuracy of the workpiece. By analyzing the common detection methods, application scope and detection accuracy of straightness of guide rail parts, the application occasions and detection accuracy of each detection method are clarified. It provides a theoretical basis and guidance for testers to detect straightness and deal with errors.

Evaluation of Bolt and Guide Rail Considering Surface Roughness and Bionics in Reciprocating Motion

The temperature rise in the contact area of the sliding friction pair is an important factor that causes the sliding friction pairs to adhere and affect the movement, and the temperature of the sliding friction pair is affected by many factors. The influential trend of these factors on the temperature is analyzed by using the finite element software, the bolt and guide rail of a Gatling weapon is simulated under the condition of considering the surface roughness and bionics. The results demonstrate that the stress of the result decreases a lot when the bolt is bionic, which is 41.1% lower than the normal condition. However, the displacement increases slightly, only 0.0016mm. Bionics has more benefits than roughness in reducing stress. In the thermal situation analysis of the 10000 firing rate, the combination which comes from the general guide rail and the bionics bolt is 168.130, but the combination which comes from the general guide rail and general bolt is 86.2580. This also explains why modern Gatling weapons do not use the bionics structure, because, with the friction, its temperature is high. For continuous firing weapons, too high a temperature is a problem. If the firing rate is lower, a bionics structure can be used.

Micro feed characteristic analysis of a new crawler guide rail dual drive servo system

This paper presents a new type of crawler guide rail dual drive micro feed servo system based on “crawler type” guide rail. Through the innovative design of the crawler guide rail and the change of the working mode, the table, and the crawler type movable rail are relatively static, and the influence of nonlinear friction in low-speed micro feed is eliminated, so that the system can have a lower stable speed limit and realize accurate micro feed control. The Euler-Bernoulli beam element with axial and torsional degrees of freedom is used to describe the axial and torsional vibrations of the ball screw, and the lumped parameter method is used to analyze other parts of the feed system, and the electromechanical coupling dynamic model considering the nonlinear friction is established. The transfer function block diagram is used to characterize the motion relationship of the crawler guide rail dual drive servo feed system. The response difference between the screw single drive system and the new crawler guide rail dual drive system is analyzed by simulation when feeding at constant or variable speed, and the influence of different feed speed on the dynamic performance of the system. The results show that the low speed micro feed performance of the new crawler guide rail dual drive servo system is obviously better than that of the screw single drive system under the condition of constant speed or variable speed.

High-Precision Guide Stiffness Analysis Method for Micromechanism Based on the Boundary Element Method

The guide stiffness performance directly affects the motion of the micromechanism in accuracy and security. Therefore, it is crucial to analyze the guide stiffness precisely. In this paper, a high-precision guide stiffness analysis method for the micromechanism by the boundary element method (BEM) is proposed. The validity and accuracy of the analysis method are tested by a guide stiffness experiment. In order to ensure the accuracy and safety during the micromechanism motion, a guiding unit of the micromechanism was designed based on the guiding principle. The guiding unit can provide parasitic motion and additional force in the motion of the micromechanism. Then, the stiffness equations of the beam element are derived by the boundary element method. The stiffness equation of straight circular flexure hinge is analyzed by rigid discretization and rigid combination, and the guide stiffness of the mechanism is investigated by rigid combination. Finally, according to the actual situation, the stiffness matrix of the guide rail (Kb) was proposed, and the analytical value of the guide stiffness was calculated to be 22.2 N/μm. The guide stiffness performance experiment was completed, and the experimental value is 22.3 N/μm. Therefore, the error between the analysis method and the experimental results is 0.45%. This study provides a new method for the stiffness analysis of high-precision micromechanisms and presents a reference for the design and stiffness analysis of complex structures. This method is helpful for stiffness analysis of the microrotary mechanism with high accuracy.

An assembly precision prediction method for customized mechanical products based on GAN-FTL

Reliable prediction of assembly precision is important for quality control of customized mechanical products characterized by individual customization, small batch size, and multiple varieties, resulting in insufficient samples for predicting assembly performance. A customized mechanical product assembly precision prediction method based on generative adversarial networks and feature transfer learning (GAN-FTL) is proposed in this paper. A GAN is built based on high quality data (source domain) to generate auxiliary samples with high fidelity and large sample size. A support vector machine is used to generate pseudo-tags for auxiliary samples. Features of source domain, target domain and auxiliary samples from different distributions are transferred to the same distribution to achieve multi-source fusion of measured and simulated data using FTL. Data after FTL is used to train the assembly precision prediction model. The elevator guide rail assembly is taken as the case study. T70/B and T90/B guide rail assembly are selected as the source and target domains, respectively. FTL was performed between the source and target domains, with different sample sets for comparison and compared with five different methods. Experimental results show that the prediction accuracy of the target domain is improved when the auxiliary sample size is 300, 400, and 500, and the accuracy improvement of the five methods are 15.37%, 12.17%, 9.68%, 6.29%, and 4.31%, respectively, which verified the effectiveness and usability of the proposed assembly precision prediction method based on GAN-FTL.

A High-Speed Precision Bearing Internal Grinding Machine and Grinding Process

In order to meet the requirement of grade P2 bearing grinding, we designed a high-speed internal grinding machine used for bearing raceway and inner circle grinding. The machine adopts T-type layout and 4-axis NC linkage. It is supported by hydrostatic pressure and driven directly by torque motor. Besides, it is equipped with high-speed hydrostatic grinding wheel spindle of ELKA. Our design includes hydrostatic workpiece shaft, hydrostatic turntable and hydrostatic guide rail. The design of this machine can ensure the high-speed grinding process and research has good engineering application value. Finally, the designed precision grinding machine is used to grind the P2 bearing raceway with reasonable processing technology.

A Novel Error Equivalence Model on the Kinematic Error of the Linear Axis of High-End Machine Tool

The kinematic errors of the linear axis play a key role in machining precision of high-end CNC (Computer Numerical Control) machine tool. The quantification of error relationship is still an urgent problem to be solved in the assembly process of the linear axis, especially considering the effect of the elastic deformation of rollers. A systematic error equivalence model of slider is proposed to improve the prediction accuracy for kinematic errors of the linear axis which contains the base, the linear guide rail and carriage. Firstly, the geometric errors of assembly surface of linear guide rail are represented by small displacement torsor. According to the theory of different motion of robots, the error equivalence model of a single slider is established, namely the geometric error of assembly surface of linear guide rail and the pose error of slider is equivalent to the elastic deformation of roller. Based on the principle of vector summation, the kinematic error of a single slider is mapped to the carriage and the kinematic error of the linear axis is obtained. Besides, experiments validation of kinematic error model of the linear axis is carried out. It is indicated that the proposed model is accurate and feasible. The proposed model can provide an accurate guidance for the manufacturing and operation performance of the linear axis in quantification, and a more effective reference for the engineers at the design and assembly stage.