Passivation can improve the service life of the cutter, the stability of the cutting process and the quality of the machined surface. The edge of passivated cutter is not a regular arc. This paper used the method of discretizing the cutting edge axially into micro element cutting edge and was based on the basic theory of slip line field. Comprehensively considering the variation of ploughing force with cutting thickness and the characteristics of asymmetric edge shear, it pointed out the different cutting stages experienced in the cutting process of asymmetric edge cutter, and established the instantaneous milling force model of asymmetric edge cutter. Finally, a comparative analysis was carried out combining with milling experiments. The results show that the proportion of ploughing force decreases with the increase of cutting thickness in the whole cutting process; the milling force obtained from the model well accords with the experimental results. The correlation coefficient of the two is greater than 0.7, the ave-rage error is less than 5%, and the peak error is less than 15%. 

With the computational fluid software Fluent, the Realizable k-ε turbulence model was used to simulate the flow characteristics of the tandem double trapezoidal column with different spacing ratios under the Reynolds number Re=6.6×105. Seven kinds of interval ratios with interval ratio S* between 0.5~6 were selected to explain the aerodynamic coefficient, vorticity diagram and streamline diagram of the double trapezoidal column. The results show that the flow characteristics of tandem trapezoidal columns are similar to tandem cylinders and rectangular columns, and there are three modes of flow with different spacing ratios: Mode Ⅰ(Shieldeing regime), Mode Ⅱ (Reattachment regime) and Mode Ⅲ (impinging regime). There is critical interval ratio S*cr between modes. A shielding area is generated between the double trapezoidal columns at the interval ratio of S*<1; the upstream trapezoidal column trails reattach to the upper and lower surfaces of the downstream trapezoidal column at 1<S*<3. The double trapezoidal column forms its own vortex shedding at S*<3, and the vortex of the downstream changes from a single row of alternating drop (Mode Ⅰ) to a double row of drop (Mode Ⅱ, Mode Ⅲ) with the increase of the interval ratio. Affected by the upstream trapezoidal column trails, the structural stability and aerodynamic parameters of Mode Ⅰ are better than those of other modes.

In fused deposition modeling, the quality of parts can be effectively improved by optimizing the control of the filling speed. However, the filling speed is intercoupled with layer thickness, nozzle temperature and contour corner angle, so it is difficult to optimize the speed control. Based on the bivariate printing experiments, this paper used multivariate nonlinear regression method to construct an optimized control function of the filling speed by considering multiparameter synergistic coupling effect. Combining error analysis, uniaxial tensile and bending test, the effect of the optimization control of the filling speed was tested. Results show that, under the same conditions of processing parameters, by employing the speed optimization method proposed in this paper, samples’ accuracy error values are less than or closed to the average minimum accuracy error value, and the tensile performance can be enhanced slightly. Finally, the influence of this method on the tensile properties is also verified through fracture microscopic morphology analysis.

The research on fault early warning method of large-scale nuclear power equipment has far-reaching significance for timely troubleshooting, reducing safety risks, cutting unnecessary costs and improving power generation efficiency. However, most of the traditional fault early warning systems of nuclear power equipment are real-time monitoring and alarm systems and havent made full use of the data value, so their early warning effects need to be improved. This paper proposed a fault early warning method based on Bayesian LSTM. The theoretical health value of time node was predicted by neural network and was compared with the actual value to find out the abnormal value. Firstly, the healthy historical operation data was extracted from the real-time database, and then a series of preprocessing were carried out on these data. Finally, the processed data was used as training set to establish the LSTM prediction model. The cross validation method was used to reserve the test set, and the goodness of fit, mean square error and Bayesian hypothesis test method proposed in this paper were used to comprehensively verify the accuracy of the model. After the generalization ability of the model was guaranteed, the data in the real-time database was predicted in real time, and the abnormal signals during fault creep were identified by threshold method. The experimental results show that the Bayesian-BiLSTM prediction model has better prediction accuracy than the LSTM model in the case of high time delay. In case 1, for the three time series outliers, the model proposed in this paper finds the abnormal signal and gives an alarm at least 15 hours in advance compared with the existing real-time monitoring systems, and its reliability is further verified by case 2.

Robot grippers play a key role in the reliable grasp and manipulation of easy-deformable micro objects. In order to realize gripper attitude adjusting at a large extent, this study designed a kind of hybrid compliant gripper based on electromagnetic drive. Firstly, the input stiffness, rotation couplings, displacement amplification and gri-pper force of the compliant gripper were modelled based on Catiglianos second theorem. Then the material and design structural parameters were defined through the proposed optimization method of staged compliant clamp me-thod, and a single optimal objective mathematical model was built. Based finite element analysis, the designed results were verified in the field of driving force, grasping range, and grasping force, which all reach the design requirements. Finally, the performance of compliant clamps was testified on the established experiment platform. The experimental results indicate that rotation range and precision of the designed gripper fit in with expectation, and can undertake the stable grasping task for flexible lithium-battery plastic shell.

Engineering structures are often subjected to multi-dimensional random loads, and the accurate simulation of multi-dimensional random load time history is of great significance to the reliability design of structures. Based on the rigorous theoretical formula derivation of spectrum representation method about the multi-dimensional random load, the cause for the large deviation between the spectrum density matrix of the synthetic load and that of target load was analyzed in detail, providing a theory support for the multi-dimensional random load time domain simulation correction. A multi-dimensional random load time domain simulation algorithm based on the spectrum correction method was proposed. By calculating the deviation between the spectrum density matrix of the synthetic time domain load and that of the target load, the iterative technique was developed to modify the spectrum density matrix of the synthetic time domain load through feedback of errors. Furthermore, the spectrum density matrix of the synthetic time domain load was made to approach to that of the target load. Finally, a numerical analysis about three dimensional random load model was carried out. The results show that the spectrum density matrix of the synthetic multi-dimensional random load time history based on the spectrum correction method can accurately match the spectrum density matrix of the target load.

When the plug-in hybrid electric vehicle (PHEV) starts the engine in motion process, the driving torque fluctuates greatly due to the different torque response characteristics of the motor and the engine. A torque coordinated control strategy was proposed in this paper to solve this problem. First of all, the hybrid electric vehicle power system model was established on the LMS.AMESim platform. Then, a torque coordination control strategy model of “clutch oil pressure fuzzy control + motor torque compensation + engine speed control + engine torque change rate limit” based on engine idling speed ignition was built on the Matlab/Simulink platform. Finally, based on the built co-simulation platform, the mode transition co-simulation was carried out and compared with different control strategies. The results show that the proposed mode switching control strategy can greatly improve the vehicle impact and clutch friction work, and improve the smoothness of mode transitions.

Aiming at the problem that the real working load is difficult to obtain in the fatigue analysis of hydraulic excavator working device, a method based on the measuring data and rigid-flexible coupling model was proposed to evaluate the fatigue life of working device. Taking a 21-ton excavator working device as the research object, the actual working pressures and displacements were measured by the pressure and displacement sensors during the digging process for different working mediums. Next, the excavating resistance on the bucket tip was calculated by the mechanical equilibrium equation. The forces of each hinge point was obtained by the rigid-flexible coupling virtual prototype simulation in ADAMS, then the real load-time history of hinge points for multi-working conditions was composed acoording to the proportion of the working mediums. Finally, the fatigue analysis for the boom and bucket rod were conducted in nCode, and the results were compared with that of the fatigue bench test. The results show that there is a good agreement between them. The method proposed in this paper can provide basis for anti-fatigue design of hydraulic excavator working device.

A horizontal stability optimization control strategy of port overload AGV under low attachment coefficient road surface was proposed based on three-layer control structure. The MPC algorithm was used in the upper controller, which can continuously sample and predict the AGV dynamic parameters and alleviate the time lag problem of the control system caused by the series connection with the middle and lower-level controllers. The genetic algorithm was used in middle-level controller to optimize the parameters of the fuzzy controller for application to the stable control of the port AGV body. The SQP algorithm was applied in the lower-level controller to convert the driving torque optimal distribution problem into a quadratic programming sub-problem  and find an online solution. The Matlab / Simulink and Trucksim joint simulation platform based on port AGV was constructed to verifies the validity and robustness of the proposed strategy.

A widely applicable post-adaptive input shaper algorithm was proposed to solve the residual vibration of multi-axis servo system caused by the flexibility of the system in the emergency stop section of high-speed motion. The algorithm does not need to identify the system modal parameters and it is based on the recursive least square method (RLS). The residual vibration signal was used as the input of the algorithm to optimize the shaper coefficient vector with the best vibration suppression effect under the current trajectory. The adaptive forgetting factor updating algorithm was introduced to improve the tracking performance of the shaper in non-stationary environment. A full connection multilayer neural network model was established and trained by using multiple sets of excitation tra-jectory samples. It solves the problem of the original algorithm that the cost of time is significantly increased due to multiple changes of trajectory and reoptimization. The experimental results show that the residual vibration amplitude of the post adaptive input shaper with adaptive forgetting factor is reduced by 28.3% averagely and 36.9% maximally, and the convergence time of residual vibration is reduced by 28.4%, compared with the traditional post adaptive input shaper. The residual vibration amplitude of the input shaper predicted by the multilayer perceptron model is reduced by 21.6% averagely and 29.8% maximally, and the convergence time of residual vibration is reduced by 23.7%, compared with the ordinary post adaptive input shaper. The algorithm proposed in this paper has certain application significance for improving the positioning accuracy of multi-axis servo system and shortening the positioning waiting time. The introduction of multilayer neural network model improves the overall work efficiency under the condition that the expected trajectory changes frequently.

Base on the analysis of melt flow characteristics in flow channel in T-type extrusion die, a new structure of flow channel with radius-varying manifold and two different thickness choke zones was proposed in this paper. The radius-varying manifold is beneficial to shorten the melt residence time, while two different thickness choke zones is beneficial to reduce the extrusion pressure. Under the condition of uniform melt exit flow rate across the width direction of the flow channel, the differential equation of demarcation curve between two choke zones was deduced based on rheology and solved by numerical method and fitted in design. Case design was conducted with the method proposed in this paper and compared with flow channel designed with constant radius manifold and choke zone thickness. The results show that the differential equation of demarcation curve is reliable and can be used to guide the design of flow channel in T-type extrusion die. When the flow channel with radius-varying manifold and two different thickness choke zones meets the requirement of the uniformity of melt exit flow rate across the width direction of the flow channel, it can not only shorten the melt residence time , but also decrease the extrusion pressure significantly.

Angle elements play a very important role in energy absorption characteristics of tubes. However, the existing researches only study the influence of specific angle elements on crashworthiness, which is not universal. In this paper, concave corners were introduced into the cross-section design of thin walled tubes, a new concave tube was put forward to investigate the influence of angle element between 90°and 180°on crashworthiness. Crushing responses of concave tubes were studied by using both experiments and numerical simulations, through which the finite element models were well validated. Further, a range of concave tubes were parametrically modeled with angle elements. The result showed that the angle elements observably affected deformation mode, when angle element changed from 100°to 170°, Fm decreased 45.64%. Finally, theoretical expression of the mean crushing force of concave tubes was derived and the mean crushing force decreased with the increase of angle element, which was coincident with the numerical result.

A soft wearable upper limb rehabilitation robot was designed based on the principles of light weight, flexibility, easy-wear and ergonomics to make up the shortcomings of traditional rehabilitation robot, such as heavy weight, difficult to wear and poor motion flexibility. The robot body was make of elastic cloth and the pneumatic artificial muscle（PAM）was used as the antagonistic driving joint of the actuator to realize the elbow flexion/extension and pronation/supination motion. Moreover, the dynamic model of the rehabilitation robot is established according to the mathematical model of the new PAM and Lagrange dynamic equation. Aiming at the control difficulties of the soft system driven by PAMs, such as easy chattering and delayed response, a PID controller based on RBF neural network was designed. Aiming at the problem that the initial parameters of PID controller depend on experience, the fuzzy PID controller was designed to determine the optimal initial parameters of PID controller. Finally, the performance of the RBF-PID controller was verified through simulation and experimental research, and was compared with the traditional PID controller. The results show that the RBF-PID controller has fast response speed and high control stability, and it can realize the stable control of the soft rehabilitation robot.

The γ-Reθt  transition model was used to numerically simulate the boundary layer on the surface of the plate. The development of the boundary layer in the normal and the flow direction, as well as the effect of factors such as wall roughness,incoming wind speed,turbulence intensity, and pressure gradient on the boundary layer were studied. The study show that, in the transition interval, skin-friction coefficient and the total pressure at a certain height from the wall undergo abrupt changes; in the flow direction, the boundary layer continues to thicken but its growth rate continues to decline; in the laminar boundary layer, the viscous stress is dominant, but in the turbulent boundary layer, the sub-layer is firstly dominated by viscous stress, then the viscous stress decreases rapidly and the Reynolds stress increases rapidly, finally Reynolds stress is dominant in the log-law region. During the transition process, the maximum value of the viscous stress near the wall continues to increase but its attenuation becomes faster. The maximum value of Reynolds stress continues to increase but the normal height corresponding to the maximum value continues to decrease. The increase in roughness makes the viscous sub-layer of the turbulent boundary layer disappears and the log-law layer moves down. The increase of turbulence intensity and wind speed advances the transition, shortens the transition interval, and reduces the growth rate of the turbulent boundary layer. The pressure gradient has a great influence on the growth rate of the turbulent boundary layer, and the adverse pressure gradient thickens the boundary layer quickly.

It is difficult to simultaneously balance the forming accuracy and printing efficiency when filling parts at corner contour locations in fused deposition modelling due to the structural defects such as repeated and missing deposition zones and the influence of parameters such as filling speed and corner angle. In this paper, firstly, the influence of filling speed on the forming accuracy and the printing efficiency of parts at corner contour locations was studied with experimental and mathematical methods. The research results show that the forming accuracy is negatively related to the filling speed, but meanwhile relatively high forming accuracy and high printing efficiency could also be realized under a higher filling speed at corner contour locations in fused deposition modelling. The higher the filling speed, the weaker the effect on the printing efficiency,and the printing time tends to a constant value when the filling speed increases. Then, by setting the weight coefficients for forming accuracy and printing efficiency, a continuous function of the optimal filling speed and the preliminary design idea of adaptive control were proposed.

In order to measure the force loaded on bogie test bench and improve the measurement accuracy, a three-dimensional (3-D) force measuring platform with multiple force sensors connected in parallel was designed. Its measurement principle was analyzed theoretically and a Wheatstone bridge measurement circuit was built. 3-D force measuring platform is a kind of shear stress sensor, and the analysis shows that the output voltage of its mea-surement circuit has a definite linear relationship with the force loaded. The static calibration test of 3-D force measuring platform under uniaxial load was carried out and the output characteristics under uniaxial load and the interdimensional coupling effect of load measurement were analyzed. It finds that under uniaxial load, the voltage output of the measurement circuit corresponding to the loaded axis has good linearity, but the voltage output of the non-loaded axis measuring circuit is small. In this paper, the coupling degree evaluating coupling effect between dimensions and the numerical decoupling method based on least square method and BP neural network were also proposed, and their effectiveness was verified by experiments. At the same time, the orthogonal method was used to carry out the multi-axis loading test of the three-dimensional force measuring platform. The results show that the single-axis measurement error and the overall measurement error are not more than 1.5%, thus the measurement accuracy meets the test requirements.

A model of aperture measurement based on quadratic curve invariants was proposed to deal with the low detection efficiency and the problem that detection accuracy was greatly affected by the environment. The conic invariant aperture of the hole was obtained by ellipse geometry fitting on the surface of the hole. Firstly, the world coordinate system was established and the transformation relationship between the world coordinate system and the camera coordinate system was determined by calibration. The improved candy algorithm was used to extract the sub-pixel coordinates of the hole edge, and the sub-pixel coordinates of the hole edge were projected onto the hole surface according to the coordinate transformation relationship. Then, the ellipse geometric fitting of the hole edge curve on the hole surface was performed to obtain the quadratic curve invariant. Finally, the conic invariant was used to measure the aperture on the test bench, and the results were compared with those of the inner micrometer to verify the accuracy of the conic invariant model. 

A directly robust adaptive controller based on the radial basis function (RBF) neural network was proposed to solve the problem of the trajectory tracking for anti-sway control of an underacuated overhead and gantry crane with the parameter uncertainties and external disturbances. Firstly, the dynamic model of a double-pendulum crane was established by Lagrange equation of the second kind, and an ideal controller was designed for undisturbed conditions. Secondly, the RBF neural network was introduced to fit the ideal control output and its weight update rate was designed considering the effects of disturbances, after that the Lyapunov stability of the system was proved. Finally, a simulation test was carried out to verify the controller performance. The controller only takes the real-time position and speed information of the trolley as the control input, and no system parameter information is needed. The control accuracy depends on the fitting accuracy of the RBF neural network. The simulation results show that the controller proposed in this paper has excellent trajectory tracking and anti-sway performance and strong robustness.

The pre-stage asymmetry is the main factor causing the zero deviation of the jet-pipe servo valve. In view of the uneven size of two receiving holes, the misalignment of jet-pipe and the receiver and the asymmetry of the receiving hole center, a mathematical model of the jet-pipe pre-stage was established. A modified model based on definite integral was designed to deal with the asymmetry of the receiving hole center. Considering the asymmetry of the receiving area of the pre-stage, the quantitative analysis method and model of the pressure characteristics and the zero deviation value were established. The results show that the pre-stage processing, assembly and environmental effects will cause the asymmetry of the geometric structure and directly cause the zero deviation of the servo valve. The initial assembly error between the jet-pipe and the receiver, the initial error of the radius of the recei-ving hole will seriously cause the servo valve to produce a zero deviation. The servo valve produces a positive zero deviation, when the right receiving hole is smaller than the left receiving hole, the jet-pipe has an offset error to the right, and the angle between the axis of the right receiving hole and the vertical is smaller than the angle between the left receiving hole and the vertical. The experimental results are in accordance with the theoretical results. In the processing and assembly process of the servo valve, the symmetry of the pre-stage structure should be guaranteed as much as possible.

A clonal selection algorithm (CSA) for multi-robot collaborative scheduling was proposed to solve  the difficulties in controlling and optimizing the task assignment and scheduling of multi-robot in the same period in intelligent manufacturing system. Firstly, the initial conditions of multi-robot task were analyzed. Then taking the task completion as the constraint condition and taking task flow time, single robot maximum cost and multi-robot total cost as the objective function, a mathematical model of multi-robot task allocation and scheduling optimization was constructed. The affinity function was introduced to dynamically change the parameters of clone, mutation and selection, so as to improve the computational efficiency. Finally, the scheduling method was verified by Gantt chart analysis. The results show that the proposed method is stable and feasible. Meanwhile, the experiments show that the clonal selection algorithm has the superiority of fast convergence speed and high calculation accuracy, and can optimize various indicators under complex multi-task conditions.

The surface wettability and mechanical properties of Nd: YAG crystals were investigated to study the influence of plasma jet on Nd: YAG crystals by using self-developed plasma equipment at room temperature． The results show that the plasma has significant effects on surface properties of Nd: YAG crystals，and the wettability of Nd: YAG crystals with three different roughness is improved after plasma modification． Especially，the smooth surface changes from hydrophobic to super-hydrophilic，and the good state of hydrophilicity lasts 30 hours． The improvement of wettability of Nd: YAG surface mainly lies in the increase of oxygen-containing functional groups on the surface of the modified Nd: YAG crystals． The microhardness remains unchanged within 0 to 11h，decreases first and then increases within 11 to 22h，and remains stable within 22 to 35h after the modification． Especially，a minimal microhardness occurs between 11 to 22 h after the modification． Under the peak load of 15. 0，30. 0 and 70. 0mN，the average microhardness decreases by 56. 2%， 45. 0% and 31. 6%，respectively． And the morphology of some indentations shows features of“ladder”and“shadow” due to the rapid increase of plasticity on Nd: YAG surface 11 hours after the modification．