具有容错性能的6R机械手位置反解

Position reverse solution on 6R manipulator with error tolerance property

一般6R机械手在一个关节发生故障时,成为5R机械手或称欠自由度机械手。如果机械手抓取的是棒状物体,可以对手爪围绕棒中心线的转动姿态参数不加限制,从而把这一转动虚拟成一个未知的旋转关节,这样欠自由度机械手的位置反解问题就转换成含有6个未知量的位置反解问题。由于其结构参数将发生变化,且故障的关节是不确定的,因而反解程序须满足这一不确定性要求。一旦位置反解的运动学方程建立之后,解方程的过程与一般6R机械手的算法类似。通过数值算例,验证了机械手末端姿态γ不加限制时,这种单关节故障的一般6R机械手位置反解的个数是16。

while there happened a failure in a joint of an ordinary 6R manipulator it becomes a 5R manipulator or calls it an insufficient DOF manipulator. If the manipulator is holding a bar shaped object, there could be no restrictions added to the posture parameters for the fingers＂ rotation around the center line of bar, thus makes the rotation be virtualized as an unknown rotational joint, like this the problem of position reverse solution on the insufficient DOF manipulator was transformed into the problem of position reverse solution that includes 6 unknown quantities. On account of variations will occur on its structural parameters and the failure joint is indeterminate, as a result the reverse solution program ought to satisfy the need of uncertainty. Once the kinematics equations of position reverse solution were established, the equations solving course is similar to the algorithm of ordinary 6R manipulator. Through numerical computing example, it was verified that the number of position reverse solutions is 16 for this kind of ordinary 6R manipulator with single joint failure when there is no restriction on the posture of manipulator ends.