Moving-magnet type linear motor controlling system and manufacturing method of parts
A moving-magnet type linear motor controlling system which can highly accurately control carts even when a plurality of coil units apply forces to the carts is provided. The moving-magnet type linear motor controlling system has: a plurality of coil units having a plurality of coils; a position detecting unit for detecting the positions of the plural carts which are moved along the plurality of coil units; and a controlling unit for determining a ratio of currents which are supplied to the plural coil units on the basis of the positions of the plural carts and an impedance and thrust characteristics of each of the plural coil units.
1. A moving-magnet type linear motor controlling system comprising:
a plurality of coil units each having a plurality of coils;
a position detecting unit configured to detect positions of a plurality of carts which are moved along the plurality of coil units; and
a controlling unit configured to control currents which are supplied to the plurality of coil units on the basis of the positions of the plurality of carts,
wherein, the plurality of coil units include a first coil unit, and second and third coil units adjacent to the first coil unit, and the plurality of carts include a first cart and a second cart, and
when the first and second carts exist at positions where they receive a thrust from the first coil unit, the controlling unit controls the currents which are supplied to the first, second and third coil units on the basis of the positions of the first and second carts.
2. The system according to claim 1 , wherein when the first cart exists at a position where it receives the thrust from the first coil unit and receives a thrust from the second coil unit, and the second cart exists at a position where it receives the thrust from the first coil unit and receives a thrust from the third coil unit, the controlling unit shuts off a current which is supplied to the first coil unit.
3. The system according to claim 1 , wherein when the first cart exists at a position where it receives the thrust from the first coil unit and receives a thrust from the second coil unit, and the second cart exists at a position where it receives the thrust from only the first coil unit, the controlling unit controls the second coil unit to supply a thrust compensating for the thrust which the first cart receives from the first coil unit.
4. The system according to claim 1 , wherein the controlling unit changes a ratio of the currents which are supplied to the first, second and third coil units in accordance with an elapse of time on the basis of the positions of the carts at a predetermined time.
5. The system according to claim 1 , wherein the controlling unit determines a ratio of currents which are supplied to each of the plurality of coil units on the basis of the positions of the plurality of carts, and thrust characteristics and an impedance of the each of the plurality of coil units.
6. The system according to claim 1 , wherein the controlling unit has a switch for electrically turning off the coil unit.
7. A manufacturing method of a part, wherein the part is manufactured using a moving-magnet type linear motor controlling system comprising:
a plurality of coil units each having a plurality of coils;
a position detecting unit configured to detect positions of a plurality of carts which are moved along the plurality of coil units; and
a controlling unit configured to control currents which are supplied to the plurality of coil units on the basis of the positions of the plurality of carts,
wherein, the plurality of coil units include a first coil unit, and second and third coil units adjacent to the first coil unit, and the plurality of carts include a first cart and a second cart, the method comprising:
controlling, by the controlling unit, when the first and second carts exist at positions where they receive a thrust from the first coil unit, the ratio of the currents which are supplied to the first, second and third coil units on the basis of the positions of the first and second carts.
8. The system according to claim 1 , wherein the controlling unit controls a ratio of currents supplied respectively to the first, second and third coil units, according to a ratio of thrust constants of the first, second and third coil units.