Dalian University of Technology

Yongqing Wang

Kuo Liu

Haibo Liu

Te Li

Bo Qin

Xu Li

Mingrui Shen

Haining Liu

Zhenyuan Jia

Jiakun Wu

Lingsheng Han

Dawei Li

Yongquan Gan

Mengmeng Niu

Dongming Guo

Zhisong Liu

Wei Han

Renjie Huang

Qile Bo

Meng Lian

Chengxin Wang

Yuhang Ge

Tian Lan

Boyao Cui

Xingjian Liu

Jianhui Deng

Kang Kuang

Xiaofei Ma

Qi Luo

Junpeng Wang

Heng Chu

Minghua Dai

Ziyou Ban

Tianran Liu

Fanze Kong

Zaiyou Ban

Honghui Wang

A process for conformal processing of a cylindrical shell inner weld seam by a special mobile robot includes using a laser scanner to scan a cylindrical shell inner weld seam to obtain point cloud data of a contour of a weld seam area first. Weld seam feature identification is carried out to each generatrix, and misidentified generatrices are filtered out to obtain weld seam left and right boundaries. An ideal weld seam processing contour is generated conformally according to the appearance of the weld seam area, weld seam coarse grinding is carried out after correction and compensation, and weld seam contour information after coarse grinding is obtained by scanning after the coarse grinding is completed. Process parameters of the grinding are controlled according to an actual weld seam contour, and weld seam fine grinding is carried out to obtain a smooth weld seam contour.

Process for conformal processing of cylindrical shell inner weld seam

An on line prediction method of part surface roughness based on SDAE-DBN algorithm. The tri-axis acceleration sensor is adsorbed on the rear bearing of the machine tool spindle through the magnetic seat to collect the vibration signals of the cutting process, and a microphone is placed in the left front of the processed part to collect the noise signals of the cutting process of the machine tool; the trend term of dynamic signal is eliminated, and the signal is smoothed; a stacked denoising autoencoder is constructed, and the greedy algorithm is used to train the network, and the extracted features are used as the input of deep belief network to train the network; the real-time vibration and noise signals in the machining process are input into the deep network after data processing, and the current surface roughness is set as output by the network.

On-line prediction method of surface roughness of parts based on SDAE-DBN algorithm

The present invention proposes an in-situ freezing machining method for an integrated thin-walled array structure. In the method, the area among cups is cut off first; then, the outer walls of a cup array are machined; and finally, water filling and freezing are carried out, and in-situ freezing machining of the inner walls of the cup array is carried out. Then, hoisting and turning over are carried out, and the area among cavities is cut off; then, the outer walls of a cavity array are machined; and finally, water filling and freezing are carried out, and in-situ freezing machining of the inner walls of the cavity array is carried out. The method realizes in-situ freezing clamping of workpieces, avoids error accumulation caused by repeated installation of a fixture, and can refrigerate efficiently, suppress ambient and cutting thermal interference, and ensure the stability of freezing fixture.

In-situ freezing machining method for integrated thin-walled array structure

A prediction method of part surface roughness and tool wear based on multi-task learning belong to the file of machining technology. Firstly, the vibration signals in the machining process are collected; next, the part surface roughness and tool wear are measured, and the measured results are corresponding to the vibration signals respectively; secondly, the samples are expanded, the features are extracted and normalized; then, a multi-task prediction model based on deep belief networks (DBN) is constructed, and the part surface roughness and tool wear are taken as the output of the model, and the features are extracted as the input to establish the multi-task DBN prediction model; finally, the vibration signals are input into the multi-task prediction model to predict the surface roughness and tool wear.

Prediction method of part surface roughness and tool wear based on multi-task learning

A toolholder matched with the internal jet cooling spindle for cryogenic coolant is mainly composed of a hollow toolholder body, a high-performance thermal insulation structure and a bidirectional sealing structure. They can guide the cryogenic coolant from the spindle to the internal cooling channel of cutting tool and realize the cryogenic thermal insulation and dynamic sealing. The high-performance thermal insulation structure inside the toolholder employs the material with a low thermal conductivity and a low linear expansion coefficient to restrain the low temperature impact of cryogenic coolant on the toolholder and spindle, to ensure the dimensional accuracy and assembly accuracy of the toolholder. The bidirectional sealing structure in the toolholder uses the ultra-low temperature resistant seal rings to prevent the cryogenic coolant from leaking towards the spindle and the cutting tool, to ensure the stability of the coolant transport.

Toolholder matched with the internal jet cooling spindle for cryogenic coolant

An online geometric/thermal error measurement and compensation system for computer numerically controlled (CNC) machine tools belonging to the technical field of error testing and compensation of CNC machine tools. The online CNC machine tool geometric/thermal error measurement and compensation system includes two parts: the hardware platform and the measurement and compensation software. The hardware platform includes a unidirectional acceleration sensor, a precision integrated circuit (IC) temperature sensor, a multi-channel temperature data collector, and a geometric/thermal error measurement and compensation host. The error measurement and compensation software runs in the geometric/thermal error measurement and compensation host and realizes testing and compensation of geometric and thermal errors in machine tools, which are communicated to the FANUC CNC system.

Online CNC machine tool geometric/thermal error measurement and compensation system

A method for determining the preload value of the screw based on thermal error and temperature rise weighting. Firstly, thermal behavior test of the feed shaft under typical working conditions is carried out to obtain the maximum thermal error and the temperature rise at the key measuring points in each preloaded state. Then, a mathematical model of the preload value of the screw and the maximum thermal error is established; meanwhile, another mathematical model of the preload value of the screw and the temperature rise at the key measuring points is also established. Finally, the optimal preload value of the screw is obtained. The thermal error of the feed shaft and the temperature rise of the moving components are comprehensively considered, improving the processing accuracy and accuracy stability of the machine tool, and ensuring the service life of the moving components such as bearings.

Method for determining the preload value of the screw based on thermal error and temperature rise weighting

The present invention relates to a slanting-bed feed processing machine tool of a large propeller. The machine tool comprises a slanting column feed bed, a machine tool spindle, a workpiece rotary worktable, a large propeller and a bed feed mechanism. The present invention coordinates the geometrical relationship between the machine tool and the large propeller to ensure that the slanting column feed bed moves between two blades, thereby reducing the overhang length of the spindle. Different forms of workpiece rotary worktables and bed feed mechanisms are selected according to different slanting column feed beds. Four types of slanting column feed beds are designed, which can be selected, optimized and applied for different processing objects. The present invention enhances the processing stiffness of the spindle and solves the problem of poor processing quality of the large propeller caused by machine tool vibration.

Slanting-bed feed processing machine tool of large propeller

A magnetic-induced stiffness changed soft robot drive module includes magnetic-induced stiffness changed layer, two-degree-of-freedom pneumatic driver, magnetic core and sealing fixing device. The magnetic-induced stiffness changed layer and two-degree-of-freedom pneumatic driver are printed and formed. The magnetic core can be deformed together with the driver, and a magnetic field can be generated when it is energized. After the magnetic core is installed into the two-degree-of-freedom pneumatic driver, then assembled with the sealing fixing device, a soft robot drive module with one end fixed is finished. The magnetic-induced stiffness changed layer has the fast, reversible and controllable stiffness adjustment ability under the action of electromagnetic field. As its hardness is greater than that of the two-degree-of-freedom pneumatic driver and its position is outside the air cavity, the two-degree-of-freedom pneumatic driver can be restricted from over-expansion and over-extension in the axial direction, making its pneumatic bending deformation controllable.

Magnetic-induced stiffness changed soft robot drive module and production method thereof

The invention provides a dynamic seal test device for cryogenic fluid medium. The dynamic seal test device includes stator unit, rotor unit, slipway, servo motor unit and sensors. The tested seal is installed inside the stator, and the thermal insulation stator and vacuum rotor together form a dynamic seal test structure. The seals and shaft sleeves can be flexibly replaced, which is beneficial to study the influence of different seal types, structure, and seal land configurations on the sealing performance. The servo motor provides power for the rotor and controls the rotation speed. The device greatly improves the thermal insulation capacity to avoid the gasification for the cryogenic fluid medium induced by the heat transfer from environment so that ensuring the stability of the test device.

Dynamic seal test device for cryogenic fluid medium

A spindle thermal error compensation method which is insensitive to the disturbance of the cooling system is provided, belonging to the technical field of error compensation in numerical control machine tools. First, the spindle model coefficient identification test, based on multi-state speed variable, is performed; after which, based on the correlation analysis between temperature and thermal error, the temperature measurement point, significantly correlated with the axial thermal error of the spindle, is determined. Next, a spindle thermal error model is established, which is insensitive to the cooling system disturbance. In addition, the coefficients in the model are identified under constraint condition, according to the nonlinear quadratic programming algorithm. Finally, based on the OPC UA communication protocol, the compensation value, as calculated by the model, is input to the numerical control system, in order to realize the compensation of the spindle thermal error.

Spindle thermal error compensation method insensitive to cooling system disturbance

A large-panel ultrasonic on-machine scanning thickness measurement equipment and method is disclosed. A GNCMT is adopted as the measuring machine main body on which a measured large panel is clamped and conducts scanning measurement motion; a non-contact ultrasonic measurement device is installed on the spindle of the machine tool for realizing transmission and acquisition of ultrasonic signals; a coupling liquid circulation system with the functions of multi-layer filtering, flow monitoring and regulation is set up; a jet flow immersion coupling mode is adopted on the surface of the measured large panel, and micro-emulsion cutting fluid is used as compatible coupling liquid of ultrasonic on-machine thickness measurement; and the coupling liquid is recycled, purified and stably supplied circularly. The thickness measurement equipment has high multi-function integration and reliable performance. It is easy to operate and highly automated, which effectively realizes nondestructive, accurate, efficient on-machine wall thickness measurement of the large panel.

Large-panel ultrasonic on-machine non-contact scanning thickness measurement equipment and thickness measurement method

A self-adaptive compensation method for feed axis thermal error, which belongs to the field of error compensation in NC machine tools. First, based on laser interferometer and temperature sensor, the feed axis thermal error test is carried out; following, the thermal error prediction model, based on the feed axis thermal error mechanism, is established and the thermal characteristic parameters in the model are identified, based on the thermal error test data; next, the parameter identification test is carried out, under the preload state of the nut; next, the adaptive prediction model is established, based on the thermal error prediction model, while the parameters in the measurement model are identified; finally, adaptive compensation of thermal errors is performed, based on the adaptive error prediction model, according to the generated feed axis heat.

Self-adaptive compensation method for feed axis thermal error

A rapid detection method for the geometric accuracy of the linear motion axis of an NC machine tool, uses accelerometers to measure the acceleration perpendicular to the direction of motion when the linear motion axis moves at a uniform speed. Firstly, the measuring device is mounted on the linear motion axis, and the upper measurement system automatically performs multi-channel acquisition and storage of the motion point acceleration data. Then, filter the acceleration data at the different speeds. Finally, the displacement data is obtained by quadratic integration of the filtered acceleration data in the time domain. Then calculate the straightness of the linear motion axis using the End Point Fit method, and complete the rapid measurement of the straightness of the linear motion axis of the machine tool. This can realize the rapid measurement of the geometric accuracy of the linear motion axis of the machine tool.

Method for the rapid detection of the geometric accuracy of the linear motion axis of an NC machine tool

An application method of the thermal error-temperature loop in the spindle of a CNC machine tool. This uses a bar and two displacement sensors to determine radial thermal errors of the spindle. Meanwhile two temperature sensors are used to determine the temperature of the upper and lower surfaces of the spindle box. Then, the thermal error-temperature loop is drawn with the temperature difference between two temperature sensors as the abscissa and the radial thermal error of the spindle as the ordinate. Finally, the loop is employed to analyze the mechanism of the radial thermal deformation of the spindle and the thermal error level is evaluated. Since the method is based on measured data, the results of the analysis are closer to the reality, compared to those from the numerical simulations.

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Dalian, China

Yongqing Wang