| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to carry out adjustable-speed control without increasing the burden of treatment at control side by changing the rotation gently during ordinary forward and reverse rotations by revising excitation pattern to be used for power application to each phase of a stepping motor. SOLUTION: When control data transmitted from engine control ECU2 has changed from retention to open valve or from open valve to retention, a stepping motor 1b is rotated by 0.5 step in open valve direction; when a change occurs from retention to close valve or from close valve to retention, the stepping motor 1b is rotated by 0.5 step in close valve direction. When the control data are continuously open valve or already in open valve, the stepping motor 1b is rotated in 1 step unit for open valve or in open valve direction; if continuous retention occurs, the stepping motor 1b is stopped at that position. Thus, the stepping motor can be speed-adjusted adequately and step-out can be prevented. |
