多点二次曲面接触运动副的自由度方向识别方法

Determining the DOF's Directions in the Tangent Space of Multi-contact Joint

在多点曲面接触形成的多自由度运动副中,由于未知运动的显式表达,跟踪动体轨迹较为困难。一般来说,根据旋量理论由接触关系可以确定运动的切空间,但难以确定切空间中哪些矢量代表运动副自由度的切矢量;这是因为切空间是由运动副自由度切矢量生成的线性空间,包含比实际自由度切矢量多得多的成员。提出一种二阶干涉检测方法在运动副切空间中识别其自由度切矢量的方法。使用识别出的自由度切矢量可以进一步跟踪三维装配模型中的邻近接触状态,为建立机械系统整体位姿空间打下基础。

It is a difficult problem to trace the location of the moving body at a joint formed with a set of contact points on surface bodies because its motion is not explicitly expressed.Generally,the tangent space of the joint motions at the current location can be determined by using a method based on screw theory,but it cannot tell which vectors in the tangent space represent the tangent directions of the motions along individual motion parameters of the joint;this is because the tangent space is a vector space spanned from the tangent vectors of the joint＇s DOFs,which consists of much more elements than the DOF tangent vectors.An approach is presented for determining the DOF tangent directions in the tangent space of a multi-contact joint based on checking the second-order interference between the contacting surfaces forming the joint.By means of the identified directions,the neighboring configurations of the joint can be calculated,which supports the direct construction of the configuration space of a 3D assembly models.