Planning and execution of straight line manipulator trajectories
Planning and execution of straight line manipulator trajectories
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DOI：
10.1147/rd.234.0424
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发表时间：
1979-07
影响因子：
1.3
通讯作者：
R. Taylor
中科院分区：
文献类型：
--
作者：
R. Taylor
最近开发的机械手控制语言通常将运动指定为固定在机械手末端的工具要通过的点序列。如果刀具在用户指定的点之间沿直线移动，则这种运动规范形式的有效性大大提高。本文描述了实现这种直线运动的两种方法。第一种方法是对R.Paul在1974年提出的方法的改进。在运动过程中，中间点沿笛卡尔直线路径以规则的间隔进行插补，并求解机械手的运动学方程以产生相应的中间关节参数值。这里开发的路径内插函数具有几个优点，包括更少的计算成本和更好的运动特性。第二种方法使用运动规划阶段来预计算出足够多的中间点，以便在保持刀具在近似直线路径上的同时，通过关节参数值的插补来驱动机械手。这种技术大大减少了实时计算，并允许更容易地处理因退化关节对齐而产生的问题。规划是通过一种高效的递归算法来完成的，该算法只生成足够的中间点来保证刀具对直线路径的偏差保持在预先指定的误差范围内。
Recently developed manipulator control languages typically specify motions as sequences of points through which a tool affixed to the end of the manipulator is to pass. The effectiveness of such motion specification formalisms is greatly increased if the tool moves in a straight line between the user-specified points. This paper describes two methods for achieving such straight line motions. The first method is a refinement of one developed in 1974 by R. Paul. Intermediate points are interpolated along the Cartesian straight line path at regular intervals during the motion, and the manipulator's kinematic equations are solved to produce the corresponding intermediate joint parameter values. The path interpolation functions developed here offer several advantages, including less computational cost and improved motion characteristics. The second method uses a motion planning phase to precompute enough intermediate points so that the manipulator may be driven by interpolation of joint parameter values while keeping the tool on an approximately straight line path. This technique allows a substantial reduction in real time computation and permits problems arising from degenerate joint alignments to be handled more easily. The planning is done by an efficient recursive algorithm which generates only enough intermediate points to guarantee that the tool's deviation from a straight line path stays within prespecified error bounds.