PURPOSE:To ensure accurate positioning at a minute distance space for a traveling object which is affected by nonlinear friction, by giving attention to the elastic deformation degree between the traveling object and a driving motor and at the same time giving consideration to a sudden change of the frictional force. CONSTITUTION:A traveling object is affected by the nonlinear frictional force with a positioning device provided with said traveling object and a driving motor. When the traveling object is positioned toward the positive (negative) direction from its pause state by a distance DELTAY (DELTAY0), the pause position of the traveling object is referred to as Y=0 along with the position of the driving motor set at X=0 where the energy stored in an equivalent spring provided between the driving motor and the traveling object is set at 0. In such a case, the control is carried out in order of the next (1)-(3). That is, the driving motor is actuated until z(=Y-X)=-fs(+fs) is satisfied (1); the driving motor is accelerated in the negative direction until z=-fm(+fm) is satisfied (3); and the driving motor is accelerated in the positive (negative) direction until the revolving speed of the motor is set at 0. As a result, it is possible to perform accurate positioning down to a minute distance.
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