Loading robot hand, robot, and article holding method

An article holding method by a loading robot hand, the loading robot hand comprising:

• a first member;
• a second member capable of holding an article between the first member and the second member;
• a position sensor capable of detecting a position of the second member;
• and
• a drive unit that moves the second member toward and away from the first member, wherein:
• the drive unit includes:
• a drive source;
• a slidable moving base driven by the drive source;
• a fluid cylinder that is distinct from the drive source and is attached to the moving base;
• a pressure regulator capable of changing operating pressure of the fluid cylinder;
• and
• a controller that controls the drive source and the pressure regulator;
• and
• the controller controls at least one of the drive source and the pressure regulator depending on a detection result of the position sensor, and
• the article holding method comprising performing a stroke in which the second member is moved closer to the first member by
• (i) when the detection result indicates that a gap between one of the first and second members and the article is a first distance, executing a first process of driving, of the drive source and the fluid cylinder, only the drive source to move the moving base, the fluid cylinder, and the second member for a portion of the stroke, and
• (ii) when the detection result indicates that the gap is a second distance less than the first distance, then executing a second process of changing the operating pressure of the fluid cylinder so as to move the portion of the fluid cylinder that is movable relative to the moving base and thereby move the second member, which is not yet in contact with the article, closer to the first member for a remainder of the stroke so that the gap disappears.