A METHOD FOR CONTROLLING THE MOVEMENT OF AN APPARATUS, IN PARTICULAR A PLACE TOOL OF A DIE BONDER

A method for controlling the movement of an apparatus with N = 2 degrees of freedom x1,...,x N -1, z, is presented. The method comprises the steps of: determining an approximate target x-position xend app = (x1,end app,..., x N -1,end app); computing a first z-trajectory zup(t); computing an approximate x-trajectory xapp(t) = (x1 app(t),..., x N -1 app(t)) for a movement of the apparatus from a start x-position xstart to the approximate target x-position xend app; starting a movement of the apparatus from a starting point qapp(0) = (xstart, zup(0)) along a first trajectory qapp(t) = (xapp(t), zup(t)) by means of a control system; upon obtaining a corrected target x-position xend = (-x1,end,..., x N -1,end) at a time t corr, determining a corrected x-trajectory xcorr(t) = (x1 corr(t),..., x N -1 corr(t)) to xend satisfying xcorr(t blend) = xapp(t blend), where t corr = t blend and moving the apparatus along a second trajectory qcorr(t) = (xcorr(t), zup(t)) for t > t blend by means of the control system; determining an earliest time t 2 : = min{t|xcorr(t) = xend} at which xcorr(t 2) = xend) computing a second z-trajectory zdown(t) from a maximum z-position zmax to a target z-position zend such that for t t 2, zdown(t) > z2 for a given safe height z2 with zmax > z2 > zend, and zdown(t down) = zup- (t down) = zmax for some time t down > t blend; and moving the apparatus along a third trajectory qfinal(t) = (xcorr(t), zdown(t)) for t > t down by means of the control system.