METHOD FOR EVADING SUDDEN ATTITUDE CONTROL OPERATION OF COAXIAL WRIST ROBOT

摘要

PURPOSE: To evade sudden operation as to the attitude control operation when the coaxial wrist robot is almost at a specific attitude. ;CONSTITUTION: The robot which has a coaxial wrist consisting of an α, a β, and a γ axis is placed in smooth attitude control operation from a point P to a point Q. An operation command is corrected which determines the attitude so that an operation track P' surely passing a range B wherein the robot is considered to be at the specific attitude is changed into P'A from a point P' before the robot enters a dangerous area where sudden operation is caused. In the figure, A is a singular attitude point. A wrist style determining process is performed almost when the coaxial wrist robot reaches the point A from P' so that flip/non-flip inversion is performed, and the abrupt rotations of the α axis and γ axis are evaded. The robot is made to gradually approach a broken line P'Q' from the point A and return to the original operation track from a point Q'. The approach (to P') to the singular attitude is judged by comparing a β value at an interpolation point on the original operation track with a previously set critical value K of |β|. The wrist style determining process utilizes algorithm using an index for considering the (β, γ) value at a last interpolation point.;COPYRIGHT: (C)1996,JPO