Control apparatus for a linear motion stage, and linear motion system

A linear motion system comprising:

• a linear motion stage including:
• a linear motor;
• and
• a linear encoder;
• and
• a control apparatus including:
• a first filter adapted to filter a frequency of a signal received from a linear encoder of the linear motion stage;
• an adder adapted to add an input signal representing a command position and a negative of an output signal of the first filter;
• a control unit adapted to generate a control signal to control the linear motion stage based on an output signal of the adder;
• and
• a second filter adapted to filter a frequency of the control signal;
• wherein input terminals of the first filter and the second filter include a correction table for storing cut-off frequencies and damping rates measured according to driven positions of the linear motion stage, the first filter and the second filter adapted to apply the correction table to determine a cut-off frequency of the first filter and the second filter and the damping rates according to the driven positions of the linear motion stage;
• and
• wherein if the linear motion stage is placed between two adjacent ones of the driven positions, the cut-off frequency of each of the first filter and the second filter and the damping rate are obtained by an interpolation between the cut-off frequency and damping rate of one of the adjacent driven positions and the cut-off frequency and damping rate of the other of the adjacent driven positions.