针对DELTA并联机械手的振动与冲击问题,提出一种适用于DELTA并联机械手P-A-P(pick and place)拾取轨迹的梯形加速度算法。该算法采用高次多项式为过渡曲线并考虑端点处的边界条件,与电机控制中常用的修正梯形、正弦和多项式加减速算法相...针对DELTA并联机械手的振动与冲击问题,提出一种适用于DELTA并联机械手P-A-P(pick and place)拾取轨迹的梯形加速度算法。该算法采用高次多项式为过渡曲线并考虑端点处的边界条件,与电机控制中常用的修正梯形、正弦和多项式加减速算法相比,能在满足并联机械手高速运行的情况下,尽可能地减小末端执行器的振动和电机轴的冲击。通过虚拟样机仿真,测得末端加速度和电机轴扭矩曲线,并与修正梯形加减速算法的结果进行比较,证明该算法在减小末端冲击和振动方面具有更大的优越性,满足机械手的要求。展开更多
Watershed segmentation is sensitive to noises and irregular details within the image,which frequently leads to a serious over-segmentation Linear filtering before watershed segmentation can reduce over-segmentation to...Watershed segmentation is sensitive to noises and irregular details within the image,which frequently leads to a serious over-segmentation Linear filtering before watershed segmentation can reduce over-segmentation to some extent,however,it often causes the position offset of object contours.For the purpose of reducing over-segmentation to preserve the location of object contours,the watershed segmentation based on the hierarchical multi-scale modification of morphological gradient is proposed.Firstly,multi-scale morphological filtering was employed to smooth the original image.Then,the gradient image was divided into multi-levels by the volume of three-dimension topographic relief,where the lower gradient layers were further modifiedby morphological closing with larger-sized structuring-elements,and the higher layers with the smaller one.In this way,most local minimums caused by irregular details and noises can be removed,while region contour positions corresponding to the target area were largely preserved.Finally,morphological watershed algorithm was employed to implement segmentation on the modified gradient image.The experimental results show that the proposed method can greatly reduce the over-segmentation of the watershed and avoid the position offset of the object contours.展开更多
文摘针对DELTA并联机械手的振动与冲击问题,提出一种适用于DELTA并联机械手P-A-P(pick and place)拾取轨迹的梯形加速度算法。该算法采用高次多项式为过渡曲线并考虑端点处的边界条件,与电机控制中常用的修正梯形、正弦和多项式加减速算法相比,能在满足并联机械手高速运行的情况下,尽可能地减小末端执行器的振动和电机轴的冲击。通过虚拟样机仿真,测得末端加速度和电机轴扭矩曲线,并与修正梯形加减速算法的结果进行比较,证明该算法在减小末端冲击和振动方面具有更大的优越性,满足机械手的要求。
基金National Natural Science Foundation of China(No.61261029)
文摘Watershed segmentation is sensitive to noises and irregular details within the image,which frequently leads to a serious over-segmentation Linear filtering before watershed segmentation can reduce over-segmentation to some extent,however,it often causes the position offset of object contours.For the purpose of reducing over-segmentation to preserve the location of object contours,the watershed segmentation based on the hierarchical multi-scale modification of morphological gradient is proposed.Firstly,multi-scale morphological filtering was employed to smooth the original image.Then,the gradient image was divided into multi-levels by the volume of three-dimension topographic relief,where the lower gradient layers were further modifiedby morphological closing with larger-sized structuring-elements,and the higher layers with the smaller one.In this way,most local minimums caused by irregular details and noises can be removed,while region contour positions corresponding to the target area were largely preserved.Finally,morphological watershed algorithm was employed to implement segmentation on the modified gradient image.The experimental results show that the proposed method can greatly reduce the over-segmentation of the watershed and avoid the position offset of the object contours.
