Traditional product design method has many problems on requirements elicitation, such as unitary method, poor timeless and strong subjectivity. So a method of product requirements analysis based on Big Data and rough set was put forward. By the web crawler technology, designer could real-time acquire vast and unstructured product requirements in a variety of information carrier. By the Big Data analytic tool and rough set, the types of different semantic user requirements could be acquired. By the house of quality, product requirements were converted to the corresponding engineering design parameters, thus making sure the direction of product design was right. In addition, taking the "Galaxy S6 Edge" for example, by the Big Data analysis of this mobile phone's user comments in micro-blogging and Jingdong MALL and the using of user requirements calculation method based on rough set, the effectiveness of the proposed method is verified.

The research on uncertainty requires many duplications and undoubtedly it puts forward a giant challenge to numerical simulations which is time-consuming. The amount of computation in the study of uncertainty can be effectively reduced through design of experiment method, but the current researches on design of experiment method about uncertainty mainly concentrate on traditional methods. Aiming at the problem, in order to address the problem and attain an accurate uncertainty assessment through reasonably allocating computational resources, the sequential design of experiment method with three stages was constructed based on the Stochastic Kriging metamodel with finite sampling. At the beginning, the criterion to choose the predetermined number and distribution of samples to attain certain accuracy of stochastic metamodel was proposed through the simplification of IMSE at specific sampling states. In addition, the criterion to obtain the optimum based on the predetermined information was also derived to simultaneously take the state and distribution of samples into account. Moreover, traditional methods were used to do the comparison with the proposed method, and the feasibility and advantages of proposed method were verified by examples with uncertainty, in which stochastic metamodel with more accuracy was achieved by using the same amount of sampling as traditional methods.

A new algorithm for obtaining concatenation curves between segments in operational space related to continuous trajectory planning of industrial robots is introduced, which is to improve motion speeds of industrial robots when they transit between segments. The main aim of the algorithm was to make full use of industrial robot, try to improve their speed and reduce the time needed in transition section with ensuring the precision in transition section and the physical constraints of industrial robot. And the computation procedure of the algorithm should be as simple as possible, so as to be easy for the online trajectory planning and improve the generality of the algorithm. The algorithm used the via-point as a reference to obtain two transition points according to the specified transition radius, and each transition point had a non-zero velocity. A novel finite sine series function was used to interpolate the trajectory between the transition points, while conventional linear or circular trajectory planning algorithms with boundary points satisfying velocity and acceleration constraints could be employed to interpolate the trajectory between transition points and other points. The effect of the algorithm was verified by simulation in MATLAB and experiment in a 2-DOFs high speed parallel manipulator. The algorithm can realize the online trajectory planning of typical robot paths. Its trajectory is fixed even when path velocity is modified, and its computation procedure is relatively simple, and hence has much potential in many applications.

Singular configuration seriously affects the performance of the parallel robotic mechanisms. It is essential to further investigate the singularity-avoidance problem on the basis of obtaining the singularity distributing regularity of the mechanism. The geometric property of the singularity-locus and the singularity-free path planning of the Gough-Stewart parallel mechanism were explored. The position-singularity locus equation of the mechanism was constructed and the case that every singularity locus in the series of the moving plane was a quadratic curve with obvious geometric property was pointed out. Based on the geometric property of the singularity locus, the general discriminating method for the presence and absence of the singularity-free motion path was represented when the starting point and the object point were given. When the singularity-free motion path was existent, the implemented method for the singularity-free path was provided. The validation of the aforementioned methods was tested and verified by applying numerical examples. The investigation has important theoretical significance and practical reference value for the exploration of the singularity-avoidance of the parallel robotic mechanisms.

To solve the large springback problems of sheet after the creep age forming, based on the displacement adjustment (DA) method, the die surface adjustment methods which considered horizontal direction displacement in different compensation directions were proposed. The finite element model of sheet forming was established by using the software ABAQUS, and the forming processes were simulated. The processes of springback compensation were carried out separately by using the original displacement adjustment method and the improved ones. The results showed that the forming parts could meet the precision requirement with 5 times of iteration by using the original method, while only 3 times were needed by using the improved methods and forming parts reached a higher precision. The advantages of improved methods which are fast convergence rate and high precision are confirmed.

The traditional spraying water and gas fire extinguishing system can not meet the growing fire-fighting requirements of large space buildings, and then intelligent fire water cannons have gradually become the new fire-fighting equipment for large space and industrial applications. For the jet fire of current intelligent fire water cannons had a big error, jet trajectory models for fire water cannons were built in consideration of air resistance. The characteristics of jet trajectory were analyzed based on the model, then initial elevation angle was solved with considering the positioning rotation angle. The initial parameters and mutual restraint between them for the proposed jet trajectory model were verified and improved through simulation experiments. In the actual test environment, the initial elevation angle calculated by the proposed model was corrected and section ally compensated. Experimental results showed that intelligent fire water cannons based on the proposed jet trajectory models considering air resistance would achieve positioning time of less than 30 s. The deviation between the drowning center point and ignition source was less than 0.3 m, and the range error met the national standard. This method can provide references for the control and research of the intelligent fire water cannons.

The stress analysis of contact stress field for a certain type of electrical connectors was carried out to find the law of stress change by using ANSYS. The numerical analysis was performed, which mainly included the stress field distribution,deformation of jacks and the change of contact force between pins and jacks with the temperature increase. Finally the experimental verification and the data analysis were done. The results showed that as the temperature increased,the maximum deformation increased,the maximum contact force and the contact areas were reduced. For small size jacks,the maximum equivalent stress at the slot bottom increased considerably with temperature rising,thus the phenomenon of fatigue or rupture was likely to occur under the alternating load conditions. Through the analysis, it is known that the change of the maximum equivalent stress is determined by the combined results of temperature softening effect and thermal stress enhancement. The feasibility of the proposed method is verified by contact pressure test, and it is a better method to study the working stress of electrical connectors.

According to the tooth surface equation of arc cylindrical gear and the characteristic of tooth surface composition, the tooth composition characteristics of a class of cylindrical gear with curvilinear shape were presented. One-parameter surface enveloping method in gear meshing principle was used, and the general mathematical equations and conjugate tooth surface equation were deduced by coordinate transformation. Taking the tooth surface equation derivation of arc cylindrical gear as an example, the space meshing mathematical model of arc cylindrical gear was derived. In order to validate the correctness of this method, the three-dimensional model of arc cylindrical gear was established by UG software. The study results offer theoretical supports for new tooth line design and studies on new cylindrical gear with curvilinear shape.

In order to alleviate the inherent problems which appear welding bond on the gear tooth surface caused by local high temperature in the process of meshing transmission, 27 groups of factors level test were designed based on quadratic regression orthogonal design method, a single tooth was analyzed using ANSYS software by adding boundary conditions, and the highest temperature of a single tooth was got by using the Design-Expert software to analyze the test data. The results showed that the mean square of speed z₁, torque z₂, gear tooth width z₃ and gear pressure angle z₄ was 556.82, 1813.69, 278.17, 20.02, respectively. The order of four factors affected the highest temperature of tooth body was torque z₂, speed z₁, gear tooth width z₃, gear pressure angle z₄; the highest temperature of gear body would increase with the increase of speed z₁, torque z₂ and gear tooth width z₃, the highest temperature of gear body would decrease with the increase of gear pressure angle z₄. The conclusion has reference value to the gear design.

Based on the inversion principle, a new compressive inside LET flexure hinge is presented to improve the axial compressive stiffness of inside LET flexure hinge. Firstly, the structure of compressive inside LET flexure hinge was designed considering the deformation characteristics of compliant segments comprehensively. Secondly, the theoretical calculating models of the equivalent compressive stiffness and the equivalent bending stiffness for the compressive inside LET flexure hinge were set up respectively by using spring model. Meanwhile, correctness of two theoretical calculating models was validated by finite element analysis. Finally, the finite element simulation results were demonstrated by comparing the compression deflection and bending deflection of the compressive inside LET flexure hinge with that of the inside LET flexure hinge. The results showed that bending stiffness of the compressive inside LET flexure hinge was only 1.195 times of that for the inside LET flexure hinge, but the compressive stiffness was 24.532-28.141 times of that for inside LET flexure hinge. The compression stiffness of compressive inside LET flexure hinge is significantly increased in the case that the bending stiffness does not change obviously, which also proves the superiority and the reasoning of the design of the compressive inside LET flexure hinge.

In order to obtain matching relation between swash plate and piston component in the balanced two-ring axial piston pump, the force condition of swash plate was analyzed theoretically. The simulation model of balanced two-ring axial piston pump and swash plate was established based on its multi inclined slope characteristic. And the influence of the parameters such as the piston distribution circle radius, the piston diameter and the inclined slope inclination angle on the swash plate moment was also established. The results showed that the increase in inner piston distribution circle radius would reduce the swash plate total moment, while the case of outer ring was on the contrary and the influence of outer piston distribution circle radius on the total moment was far greater than that in the inner ring, so the reduction of the distribution circle radius difference between the inner and outer rings was advantageous to the reduction of the moment, at the same time, the increase in the inner piston diameter would also make the total moment reduced and that of the outer ring was also on the contrary, it's better to make the inner and outer piston diameters close to each other. The total force's trace of the swash plate of balanced two-ring axial piston pump changed along the "triangle". The characteristics of this trace were less turning point, low directional mutation and gentle force change, which made the swash plate have better stress situation, more stable operation and less vibration. The research results provide the guidance for the optimal design of the balanced two-ring axial piston pump's swash plate.

Based on the lay up design features, the structure optimization design methods and processes for the bearing structure using carbon fiber reinforced polymer were proposed. This method considered the sequence relationships of the geometry of structure, type of lay up, laminate thickness and stacking angles in the design process. Structural design could be achieved by modeling of the geometric design space, multi-objective optimization of discrete variables and the optimal decision based on the technological feasibility. The lightweight design of carbon fiber reinforced composite suspension control arm was carried out as an example. Firstly, the geometric design space of composite control arm was established on the basis of the steel control arm. Then, the convenience of lay up was treated as the principle during its structural design, and the laminate thickness was designed using the quasi-isotropic plies. Furthermore, in order to improve the stiffness and 1 order vibration natural frequency of control arm, the multi-objective optimization of stacking angles was carried out by using optimization algorithm. Finally, the technological feasibility as constraints was used during the filtering of the optimization results and finalized the structure design. Results showed that the designed composite control arm had higher stiffness and vibration natural frequency while having 47.9% less weight. The proposed method can better take into account the relationship between the structure characteristics and composite design requirements, and provide a useful reference for the development of composite structure optimization design theory and method.

Traditional design methods of underfloor lifting system tend to be conservative. In order to take full advantages of the bearing capacity of its material, a structure weight optimization method was proposed and combined with the response surface approximate model method and optimization technique. The method was based on multidisciplinary optimization software ISIGHT and ANSYS. With the analysis of design variables on the sensitivity of the response by optimal Latin hypercube experimental design method, and the final design variables were obtained. Then, the approximate model was optimized by using the multi-island genetic algorithm after the response surface model was established. Results showed that the method could greatly improve the efficiency of optimization, and the structure weight of underfloor lifting system reduced 20.64%,and the lightweight effect was obvious. The research results can provide theoretical guidance for the design of underfloor lifting system.

In the process of medical examination, the traditional manual detection method has the characteristics of low efficiency, high subjective error and high cost. According to the defects of artificial detection and the requirements of biochemical analysis system with high precision and miniaturization, a full automatic biochemical sampling system was developed. In the mechanical structure, the system had the functions of moving the liquid and taking and withdrawing the suction head. In the control method, the actuator control algorithm was optimized. Firstly, the whole system structure was designed and the control system based on the STM32 control chip was completed to meet the actual needs of the automatic sampling system. Secondly, by demonstrating the stepper motor control algorithm, the S type curve control algorithm was used, and the algorithm was optimized and implemented, thus, the control accuracy and speed was improved. Finally, in order to further improve the robustness of the system, we collated and analyzed the experimental data, and got the system error compensation curve and the method of correction. The results show that the improved system has higher accuracy of sampling, meets the actual needs more extensively, and has guiding significance for the development of medical devices.

Aiming at the problems existing in the automatic feeding, quantitative filling process of the capacitor aluminum shell such as low automation degree, low filling accuracy and so on, the control system of automatic feeding and quantitative filling for the capacitor aluminum shell was designed. The PLC of Mitsubishi FX3GA series was used to conduct the reasonable configuration of hardware and software for the control system and the hardware composition and software flow of the system were designed in detail. The touch screen of Mitsubishi GS series was used to achieve the system parameter modification and state monitoring. The system had been applied in the practical application of capacitor production enterprise and application effect showed that the system ran reliably and stably, the operation period was 10 s, the error of the quantitative filling for aluminum shell was less than 2%, and the product quality and production efficiency were improved, which could meet the production requirements of enterprises. The system has a certain popularization value.

According to the difficult problems of multimedia signal acquisition and the poor channel transmission circumstances due to the facts such as the insufficient lightness, the gas explosion proof and the zigzag mine tunnels, and so on, a new efficient wireless fidelity (WiFi) video transmission system was developed and used on the underground mine communication occasions. In the aspect of hardware for the proposed system, it mainly exploited the devices of embedded ARM processor, infrared charge-coupled device (CCD) camera, WiFi module, and so on. In the aspect of software for the proposed system, it used H.264 video codec, real time control protocol (RTP)/user datagram protocol (UDP) encapsulation, quick WiFi handover and some other information acquisition and transmission mechanism. Finally, an efficient and low power consuming underground mine wireless multimedia communication prototype was developed to meet the requirement of under ground mine multimedia supervision. Through practical testing and verification, the proposed scheme was found to be suitable for the poor working conditions such as weak lightness, explosion proof, complex transmission link, and so on. Thus it obtains efficient and reliable under-mine WiFi video transmission effect. Therefore, the designed underground mine WiFi transmission system can overcome the terrible circumstances of the transmission channel and realize the low cost real time broadband video information transmission. And it can be widely used on the occasions of the underground mine security surveillance and management.

The powered caster wheel without special decoupled mechanism that is used by the omnidirectional mobile robot can produce an extra rolling motion output of the wheel when it is making the wheel turn. It is due to the motion couple between the steering motion and driving motion. This phenomenon can lead to the motion instability and increase the complexity of the robot's motion control algorithm, which is not beneficial to the mobile robot's practical application and maneuverability. In order to solve the powered caster wheel's motion couple problem between the steering motion and driving motion, a differential planet gear was mounted between the steering transmission system and driving transmission system. By setting reasonable output transmission ratio and right motion orientation of the differential planet gear, the extra rolling motion could be decoupled from the steering motion, which could make a great contribution to the stability of the robot's motion and accurate motion control. Finally, the kinematics of the robot had been analyzed, from which the relationship of the input motor speed and the robot's velocity could be obtained. Through utilizing, the result of kinematics analyzing the robot's ability of the omnidirectional mobility can be testified and the foundation of the robot's motion control can be provided.