In order to investigate the specimen size dependence and grain size dependence on the mechanical properties for SS304 ultrathin sheet metal ,the uniaxial tensile tests were performed by using self‐designed special fixture for ultrathin sheet metal .The influence of ultrathin sheet metal thickness and grain size on the material properties were analyzed .The experiment results showed that with the decreasing of sheet metal thickness ,the material yield strength decreased at first and then increased significantly . Because when the sheet metal thickness was larger than 200μm ,surface layer effect played a dominant role;to the contrary ,be‐cause of the dual action of strain gradient effect and surface passivation membrane ,the yield strength is decreased .What's more , the grain size has been changed under the same thickness ,so when sheet metal thickness‐grain size ratio was less than 2 ,the dis‐location was easy to slip out of the free surface and the stress strain curve decreased significantly .

The springback problems of high strength steel sheet is one of the major problems in its application.Warm forming technology can significantly improve the formability of high strength steel.Taking a U-shaped part as the object,by changing the temperature and pressure force,the spring back and distortion of DP590 dual phase high strength steel was studied under warm forming process.The results show that,with the increase of temperature and pressure force,the rebound of parts gradually diminishes,but the temperature's change has no great effect on distortion,the increase of pressure force can decrease the distortion.

Warm tensile tests of B340/590DP dual phase steel and tailor welded blanks(TWBs) are carried out by using the testing machine CMT5205.The flow stress behaviors of base metal and TWBs are investigated in the temperatures range form 550 ℃ to 700 ℃ and strain rates from 0.000 1 s-1 to 0.1 s-1.Stress-strain curves for welding zone are obtained by calculation of equal jigging strain method.The models of base metal and tailor welded blanks are established by the improved model contained softening factor.The results show that the dynamic recovery and dynamic recrystallization occur obviously during warm tensile tests of base metal and TWBs.The flow stress increases with the increase of strain rates and decreases with the increase of temperature.The flow stress predicted by the proposed models well agrees with experimental results,which is reliable.

The process of vacuum forming is introduced in this article as well as the key technology of vacuum forming,including establishment of motion function and prediction of forming time.A vacuum mould for refrigerator liner is taken as an analyzing example to analyze the process of vacuum forming by numerical simulation,based on Polyflow software,which results show that the blowing time is the key factor to control the quality of products.If blowing time is too short,thinning in local or uneven will result,while if it is too long,local wrinkles and folds may occur.By combining numerical simulation technology and motion functions the optimization for forming technology is realized.

The sensitivity analysis of injection process parameters which influenced the sink marks of ABS injection parts in electronic dictionary lower cover was performed using numerical simulation technology based on Moldflow analysis.A sensitivity factor was introduced to evaluate the sensitive degree of every process parameter on the sink marks,in order to find the principal and secondary determining parameters on the sensitivity degree.The results showed that influence of the packing pressure,melt temperature and injection time on the sink marks of the ABS product were comparatively higher than that of the mold temperature and packing time.Through analyzing the diagrams of influential factors,the optimized process parameter scheme was obtained and further verified by simulation test.

In order to improve automatization of the mowing robot in its navigation ability, we use the GPS receiver and a digital box and needle. By using the technology of Kalman filter, the GPS/DR combination navigation system can improve other disadvantage of navigation technique in agriculture robots. In this paper, we introduce our GPS/DR system, and give our examination data and result

In order to solve the problems in control of the mowing robot in its avoiding stumbling bock, The method of fuzzy control with path layout is used based on the distance measure sensors .The disposal of the system of ultrasonic sensors and infrared sensors is given. The results of the experiments of the mowing robot in control of its avoiding stumbling bock through VC++ programmer show that the method is agile and steady.

根据增压柴油机废气再循环(EGR)系统的要求,采用动态矩阵控制(DMC)算法设计EGR系统控制器.通过仿真系统试验证实了所设计的控制器可以应用于柴油机EGR系统,并能够使EGR系统有效降低柴油机氮氧化物(NOx)的排放.