Patent ID: 6343243
Filing Date: 2002-01-29
Classification: B25J,G05B

Abstract:
A method for determining a number of load parameters (ml, xl, rl, &agr;l, Ix, Iy, Iz) for a load (6) which is carried by a manipulator which comprisesa number of links (2,3,4) which are movable in relation to each other, a handling member (5) for supporting a tool or a work object, which handling member is movable in relation to said links, a number of axes (A1-A6) in relation to which the links or the handling member is movable, and a motor for each axis which drives the movements of the axis in accordance with supplied reference values for the torques of the motor, characterized in that it comprises the steps of: a) appointing at least two of the axes identification axes, b) the manipulator adopting a first axis configuration (K1), c) running both identification axes such that a first movement is imparted to them which has a substantially constant velocity and which at first takes place in a first direction and then in a second direction which is opposite to the first one, measuring and recording the torque and the angle of the identification axes during the first movement, calculating the moment of gravitational force (&tgr;grav,i({overscore (&phgr;)}))of the identification axes by summation of the mean value of the measured torque in one direction of movement and the mean value of the measured torque in the other direction of movement, d) running the identification axes separately such that a second movement is imparted to them which comprises an acceleration distance and a deceleration distance measuring and recording the torque and the angle of the identification axes during the second movement, determining the acceleration by deriving measured values of the angle, calculating product elements by multiplying measured values of the torques and the calculated accelerations, whereupon the mass inertia (Ji({overscore (&phgr;)})) is calculated by correlation as the sum of the product elements divided by the sum of the accelerations squared, e) the manipulator adopting a second axis configuration (K2), whereupon steps c and d are repeated for at least one of the identification axes, f) calculating the load parameters from the calculated moments of gravitational force and the mass inertias with the aid of the physical and geometrical relations of the identification axes.