Robot controller

A robot controller for having a workpiece held by a robot in a hand thereof and for having said workpiece machined by moving it through control over the position and attitude of said hand against a tool fixedly mounted on a tool bed, comprising:

• a first memory means for storing the position of the tip of said tool fixedly mounted on said tool bed as well as the attitude of said tool, said position and said attitude being stored in the form of a four-row, four-column tool matrix represented by homogeneous coordinates of a stationary coordinate system fixed in space;
• a second memory means for storing the position of the origin of a coordinate system fixed to said hand of said robot as well as the attitude of said hand with respect to a plurality of teaching points along a machining path determined on said workpiece, said position and said attitude being stored in the form of a four-row, four-column teaching matrix at each of said plurality of teaching points represented by homogeneous coordinates of said stationary coordinate system fixed in space;
• a means for calculating as a tool transformation matrix at each of said plurality of teaching points a transformation matrix represented by homogeneous coordinates for transforming said teaching matrix into a tool matrix, with a calculation being performed by said means for calculating through the use of said tool matrix stored in said first memory means and of said teaching matrix at each teaching point stored in said second memory means;
• a first interpolation means for setting interpolation points along the machining path between any adjacent two of said teaching points according to a specified machining velocity, in order to calculate as an interpolation tool transformation matrix a tool transformation matrix at each of said interpolation points by the use of said tool transformation matrix in effect at said two adjacent teaching points;
• a second interpolation means for calculating a four-row, four-column interpolation teaching matrix which is represented by homogenous coordinates of said stationary coordinate system fixed in space and which indicates the attitude of said hand and the position of the origin of said coordinate system fixed to said hand of said robot at each of said interpolation points, through the use of said interpolation tool transformation matrix at each interpolation point calculated by said first interpolation means and of said tool matrix stored in said first memory means;
• and
• a control means for calculating rotation angles on movable axes of said robot based on said interpolation teaching matrix in effect at each interpolation point and calculated by said second interpolation means, in order to control the origin position and attitude of hand of said robot by having said movable axes follow said rotation angles.