摘要：为提高商用车的紧急避撞性能,采用了转向和制动联合避撞方式。而针对半挂汽车列车在紧急转向时容易失稳的问题,设计了考虑防止侧翻和横摆失稳的非线性模型预测控制器,并在紧急避撞场景的不同载荷和不同速度工况进行仿真验证。鉴于该控制器实时性能的不足,以其为跟踪性能的基准,设计了考虑质心侧偏角约束的线性时变模型预测控制算法,在满足避撞轨迹跟踪精度要求条件下,改善算法实时性。最后,制作了缩小版的半挂汽车列车试验车,进行紧急避撞工况的轨迹跟踪验证。结果表明,所设计的控制算法能准确跟踪目标轨迹,满足实际应用需求。

摘要：The visual inspection is an economical and effective method for welding. For measuring the feature sizes of grooves,a method based on line structured light is presented. Firstly,an adaptive algorithm to extract the subpixel centerline of structured light stripes is introduced to deal with the uneven width and grayscale distributions of laser stripes,which is based on the quadratic weighted grayscale centroid. By means of region-of-interest(ROI)division and image difference,an image preprocessing algorithm is developed for filtering noise and improving image quality. Furthermore,to acquire geometrical dimensions of various grooves and groove types precisely,the subpixel feature point extraction algorithm of grooves is designed. Finally, experimental results of feature size measuring show that the absolute error of measurement is 0.031—0.176 mm,and the relative error of measurement is 0.2%—3.6%.