As a new method for gravity compensation in two dimensions, it is prop
osed to decrease the time-average friction by use of in-plane vibratio
n. This dither effect is investigated by using a mass that slides at a
constant velocity on a level in-plane vibrating table, Its usefulness
is further demonstrated by an experiment. An application of the metho
d to gravity compensation is introduced. A motion test of a link struc
tural model with ball-bearing supports and a level in-plane vibrating
table is conducted to evaluate the performance. Experimental results s
how that the structure slides on the table with a drag-to-weight ratio
of about 10(-3) and drag-induced accelerations of about 10(-3)g.