Method and apparatus for robotic force controlled material removal with programmable overload release function

An electromechanical robotic force controlled material removal apparatus, comprising:

• a housing defining an inside space and attached to a distal end of a robot arm;
• an electromagnet having an electromagnet coil fixed within said housing;
• a follower disposed within the inside space of said housing and movable when multi-directional linear and rotational motions are given to said follower, said follower including:
• a disk-like portion disposed within the inside space of said follower and magnetically attracted by a magnetic attraction force of said electromagnet, and
• a shaft portion connected to the disk-like portion and defining a cylindrical hollow such that a lower end protrudes from a bottom of said housing, said lower end being fixed to a tool clamp for supporting a material removal tool;
• engagement support means protruding inwardly within said housing and contacting the disk-like portion of said follower;
• and
• elastic engagement means disposed within the cylindrical hollow of said follower for maintaining contact between said follower and said housing thereby allowing said follower to move both linearly and angularly in the inside space of said housing;
• means for adjusting electric current supplied to the electromagnetic coil of said electromagnet.

A method for robotic force controlled material removal through a robot having a programmable electromechanical force release mechanism connected to a material removal tool by a damping medium, the electromechanical force release mechanism comprising:

• a housing,
• an electromagnet located within the housing,
• a follower with a disk portion located within the housing and a shaft portion connected to the disk portion and the material removal tool, the shaft extending out of the housing,
• an engagement support within the housing,
• an elastic engagement means which applies a mechanical force which causes the follower to contact the engagement support,
• a means for adjusting electric current in the coil which causes the electromagnet to apply an electromagnetic force on the follower;
• said method comprising the steps of:
• setting initial threshold values of holding strength for the force release mechanism wherein the damping medium absorbs some of the vibration produced through material removal by said material removal tool;
• holding the material removal tool with the force release mechanism set to the initial threshold values;
• adjusting the initial threshold values to a desired level during a test material removal operation;
• applying the material removal tool to a workpiece;
• and
• retreating the material removal tool from the workpiece when a force acting on the tool has exceeded the adjusted threshold values.

An electromechanical robotic material removal apparatus comprising:

• a robot arm;
• a housing defining an interior space and attached to a distal end of the robot arm, wherein said housing further includes an interior shoulder protruding inwardly from an interior surface of said housing;
• an electromagnet disposed within the interior space of said housing, wherein the strength of the electromagnet is adjustable;
• a follower disposed within the inside space of said housing including:
• a disk-like portion magnetically attracted to said electromagnet and movably contacting the interior shoulder of said housing, and
• a shaft portion connected to the disk-like portion and defining a cylindrical hollow, wherein a lower end of said shaft portion protrudes from said housing and is fixed to a tool clamp for supporting a material removal tool;
• and
• an elastic element disposed within the cylindrical hollow of said follower and maintaining contact between said follower and the interior surface of said housing, wherein said elastic element allows said follower to move both linearly and angularly within the interior space of said housing.