PURPOSE: To maintain favorable accuracy despite variations in accuracy from one unit to another at the shipment of products and deterioration due to long time use, by learning and correcting current values stored in a storing means based on the amount of stepping motor drive detected using a drive amount detecting means.
CONSTITUTION: When an internal combustion engine is idling, CPU 1 controls the opening of a throttle valve 10, a drive amount detecting means, so that the number of rotations of the engine will reach a target value. When a driving command is issued by the throttle valve 10, CPU 1 reads a current value from RAM 14, a storing means, and commands it. The current command value is converted from digital into analog by a digital-to-analog converter 2. A motor current corresponding to the current command value is fed from a power supply 12 for stepping motors to each phase of a stepping motor 6. The stepping motor 6 is thereby driven to a desired step position. This maintains favorable accuracy despite variations in accuracy from one unit from another of products, and the deterioration due to long time use.
NAKAYA YOSHIMASA
TASAKA HITOSHI
Next Patent: CONTROL DEVICE FOR STEPPING MOTOR DRIVEN IN MICROSTEP