Electric control apparatus for industrial robot

An electric control apparatus for an industrial robot the arm of which is actuated to carry out machining of a workpiece by means of a machining tool attached thereto, comprising:

• memory means for memorizing a plurality of teaching points representing the contour of said workpiece to be machined;
• and
• execution means for operating said robot such that said machining tool is moved along a teaching line defined by the teaching points to carry out machining of said workpiece;
• wherein the electric control apparatus further comprises:
• a force sensor connected to detect reaction force acting on said machining tool;
• second memory means for memorizing a plurality of split points dividing the teaching line into a plurality of split sections;
• third memory means for memorizing a maximum reaction force detected by said force sensor during each machining process of said workpiece in the split sections of the teaching line;
• setting means for setting a value indicative of a limit of reaction force acting on said machining tool;
• comparison means for comparing the memorized maximum reaction force with the set value and for producing an instruction signal therefrom when the memorized maximum reaction force exceeds the set value;
• control means for ascertaining as to whether or not said comparison means produces the instruction signal therefrom at each time when said machining tool arrives at each terminal point of the split sections and for producing a control signal therefrom when applied with the instruction signal from said comparison means;
• and
• wherein said execution means is connected to operate said robot in response to the control signal from said control means such that said machining tool is once moved away from said workpiece and returned to each start point of the split sections to repeat machining in the same section.