摘要 |
In a system, an actuator is linked to a valve rotatably installed in a passage through which gas flows. The actuator changes torque to be applied to the valve so as to adjust a rotational position of the valve based on a deviation between a current position and a target position. In the system, a first storing unit stores therein a first threshold. The first threshold is defined in a variation range within which a torque parameter is variable depending on change in the torque to be applied to the valve. The first threshold allows whether there is a possibility that an operation of the actuator is unstable. If the torque parameter substantially shifts either to or through the first threshold in the variation range, a restricting unit restricts variation in the torque parameter with the gas-flow being substantially kept through the passage.
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