Patent ID: 6922034

Claim:
A method for designing an arm structure for a robot having an arm which can rotate vertically and forward over a prescribed angle around an axial line extending substantially between two shoulders, the method comprising: selecting a vertical region in front of the robot to be accessed by the arm in a fully extended state, the location of the selected vertical region being determined with respect to a reference plane; selecting a height of the axis of rotation of the arm as a midway point between an upper end and a lower end of the selected region; approximating an arcuate path of a free end of the arm caused by rotational motion of the arm in accessing the selected region with a straight line that passes through a position of the free end of the arm extending in a horizontal direction and a position of the free end of the arm for accessing the upper or lower end of the selected region, and selecting a length of the arm so that a maximum error between a linearly approximated for-and-aft distance to the free end of the arm based on the straight line approximating the arcuate path of the free end of the arm and an actual for-and-aft distance to the free end of the arm based on the arcuate path of the free end of the arm is smaller than a prescribed maximum tolerated error.