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In gear skiving, tool-chip contact condition becomes complicated when using multiple radial infeed strategy. We are interested in calculating a precise boundary of the uncut chip geometry to capture its topological variation especially in semi-/finishing-passes. To achieve this, we propose a level contour method to implicitly construct the uncut chip and gear gap geometries with contour curves. By comparing the artificial potential energy defined on the different contours, geometries of uncut chip and gear gap are successfully obtained. In addition, the implicit contour provides an efficient and comprehensive way to express the topology changes of the uncut chip geometry from the I to the U shape. By changing the radial and axial infeed rates, the proposed method is proven can advance the understanding of tool-chip contact area variation with the active contour, which can smoothly present merging, emerging and separation, for the development from single-contact to multiple-contact areas during a single-cut.

Gear skiving is a state-of-the-art technique for machining internal gears with high efficiency. Numerical simulation method being able to analyze the eccentricity error e of cutter is critical to the understanding on the formation of surface roughness in skiving process. In this work, we proposed a novel Z-map-based numerical model to calculate the surface of gear flanks with eccentricity errors up to 9 μm. Correlation between eccentricity error and gear flank profile was clarified by numerical simulation and supported by experimental verification. The results show that the eccentricity error imposed a low-frequency motion during the generation of scallop height, leading to a surface roughness with a maximal error about four times that of the theoretical roughness. The e-induced scallop height became the majority factor account for variation of surface roughness when e exceeds 1.4 and 2.3 μm for feed rates of 0.4 and 0.8 mm/rev, respectively. The experimental result further supported the capability of proposed simulation model in providing detail surface features of gear flanks in skiving process.

Power skiving is a promising method that can enhance the efficiency of gear machining. The machining mechanism is complicated due to several factors, such as the continuous variation in the rake angle and undeformed chip thickness. The tool wear process is also difficult to be evaluated due to the constantly varying in cutting conditions. Hence, to make a comprehensive understanding of the cutting process, we proposed a parametric modeling process based on the kinematics of power skiving. In this model, the undeformed cutting chip was calculated in each pass and shows the consistency with deformed cutting chip in experiments. The effective rake angle and undeformed cutting chip thickness were defined, calculated, and displayed on undeformed cutting chip for a better understanding of the cutting process. The cutting force and tool crater wear were calculated by estimating the distribution of the stress and temperature on the rake face of the cutting tool. Multiple radial-feed experimental evaluations were conducted with the gears of construction vehicles. In the results, the predicted margin of the absolute error of the normal force on the rake face was under 5% in every pass. The wear distribution on the rake face is consistent with the superimposed tool-chip contact area. The results show high potential for the optimization of the cutting tool or cutting conditions in gear power skiving.

In gear skiving, large variations in cutting features significantly affect the cutting condition and surface integrity of a newly formed gear flank (NGF). This study aimed to improve the understanding of the effects of local cutting features on the surface integrity of approach and recess NGFs from the resulting microstructure produced by the multiple radial-infeed (MRI) strategy. For the first time, the boundary of the NGF regime and associated local cutting features were calculated from the uncut chip geometry (UCG) using a novel boundary-based level contour method. The theoretical and experimental results revealed that the local rake angle and uncut chip thickness are the most influential factors altering the plastic deformation conditions of the approach and recess NGFs. For the finishing pass, the uncut chip thickness developments within approach and recess NGFs were elucidated, showing the burnishing regime dominated the recess NGF formation. The strain–stress characteristics of the recess NGF show the strain-hardening effect due to the severe plastic deformation. Kernel average misorientation mapping showed a partial reduction in the misorientation angle under the recess NGF. This points to the accumulated deformation in the interaction between successive skiving passes further facilitating the localized recrystallization. Proposed local cutting feature calculations can be applied for further kinematic parameter optimization and MRI infeed rate design.

In gear skiving, tool wear is one of the primary issues owing to the large thermomechanical cutting load. However, the effective rake angle and depth-of-cut can vary continuously throughout a single cut, leading to a complex uncut chip geometry that significantly hinders the understanding of the cutting characteristics and adds further difficulty to the prediction of tool wear. This study proposes a parametric modeling method for calculating the uncut chip geometry for each cutting pass. Developments in the rake angle and depth-of-cut (as subjected to an uncut chip) were comprehensively investigated with an aim to advance the understanding of the cutting characteristics during a single cut. Based on the uncut chip geometry, the crater wear was successfully predicted using the derived stress and temperature data, followed by a single-tooth skiving wear test verification. By comparing numerical and experimental results for crater wear, an error of less than 5 % was obtained in both depth and area. The proposed method provides a non-CAD/CAM-engine-software/environment-based alternative for calculating the process of an uncut chip geometry, clearly advancing the flexibility in further potential applications such as cutting parameter optimization and cutter design.

In this research, we mainly studied the Site selection problem of cold chain logistics in northwest of China. In the first place, we counted the demands of cold chain products in northwest territories, and then classified it into the Site selection problem in five provinces in northwest territories(Xinjiang, Qinghai, Gansu, Ningxia, Shanxi); Next, we used the Center of gravity Method to select initial location; Finally, we established the location of distribution by using Analytic Hierarchy Process (AHP)and fuzzy comprehensive evaluation method. Comparing with the traditional method, this method not only considered the cost of transportation and distance, but also deliberated the physical condition, social environment and economics condition which associated with Site selection problem.In this research, we mainly studied the Site selection problem of cold chain logistics in northwest of China. In the first place, we counted the demands of cold chain products in northwest territories, and then classified it into the Site selection problem in five provinces in northwest territories(Xinjiang, Qinghai, Gansu, Ningxia, Shanxi); Next, we used the Center of gravity Method to select initial location; Finally, we established the location of distribution by using Analytic Hierarchy Process (AHP)and fuzzy comprehensive evaluation method. Comparing with the traditional method, this method not only considered the cost of transportation and distance, but also deliberated the physical condition, social environment and economics condition which associated with Site selection problem.

This paper presents the analysis of an orthogonal multi-beam Lloyd's mirror interferometer for fabrication of two-axis gratings, which is employed as a measurement standard. Conventionally, for the fabrication of such complicated micro patterns, ultra-precision turning with a fast tool servo or lithography process with masks has been employed. However, they require long machining or fabrication time. Meanwhile, laser interference lithography such as the Lloyd's mirror interferometer is expected as a candidate for fabrication of such periodic micro patterns. In this paper, a new optical configuration is designed based on the Lloyd's mirror interferometer. In the proposed design, differing from the one in the previous study, two mirrors and a substrate are set to be perpendicular with each other to fabricate two-axis grating patterns having both symmetric profiles and uniform depths over the wide fabrication area, which has been difficult to be achieved in the previous study. A design and fabrication of the optical configuration for the orthogonal multi-beam Lloyd's mirror interferometer, and some experimental results with the interferometer will be reported.

Polarization control is of vital importance in two-axis Lloyd's mirror interference lithography to achieve the preferred interference fringes. In this work, we first establish a three-dimensional polarization ray-tracing model to trace the evolution of polarization states of incident beams through the corner-cube-like interferometer unit of an orthogonal two-axis Lloyd's mirror interferometer. With the established model, we then derive the optimal combination of initial polarization directions of the incident beams according to the orthogonality of polarization states and the contrast of interference fringes. The comparison between the simulated and experimental interference fringes obtained under different combinations of initial polarization states of incident beams verify the feasibility of the established model and the achieved optimal polarization modulation.

This paper presents a detailed analysis on the influence of misalignment errors of optical components in an orthogonal two-axis Lloyd's mirror interferometer, which can fabricate two-dimensional grating structures in a single exposure. In an ideal condition, defect-free two-dimensional grating structures can be fabricated by the interferometer. However, in a real case, visible stripes caused by misalignment errors of the optical components in the interferometer always appear on the fabricated grating structures. In this paper, theoretical analysis and experiments are carried out to analyze the influences of the misalignment errors of the optical components in the orthogonal two-axis Lloyd's mirror interferometer.

A novel progressive genetic algorithm was developed for motion planning of a three-limbed robot. The proposed motion planning method can be used to find a optimal joints trajectory from the initial to the final position and orientation. On the basis of the genetic algorithm a kind of variable structure genetic algorithm was proposed to solve the problem of motion planning of the three-limbed in dynamic environments. The variable structure genetic algorithm changes the original structure by abandoning Elitist Model, expectation selection, reproducing population and changing the probability of crossover and mutation. Experiments results show that the former algorithm is effective in static environments and the latter algorithm is adapted to dynamic environments.

It's an important step to find out the best matching scheme in the self-reconfiguring process of self-reconfigurable robots. In this paper, some relative concepts of self-reconfigurable robot and its topological representation and configuration matching are defined, and a matching arithmetic is designed and tested by genetic arithmetic. Testing results show that this matching arithmetic can search out the best matching scheme to improve the self-reconfigurable efficiency of self-reconfigurable robot.