Method of returning pointer to origin point

Abstract

There is provided a method of returning a pointer driven by a motor to an origin point disposed between a starting point and an endpoint of a movement range of the pointer, the method comprising the steps of: moving the pointer from an arbitrary point in the movement range to a reference point that is away from the starting point by not less than a distance between the starting point and the origin point; thereafter moving the pointer from the reference point toward the starting point; detecting the pointer by a sensor at a detection point whose relative position with respect to the origin point is known; and stopping, when the pointer at the detection point is detected, the pointer moving from the reference point toward the starting point at a predetermined point of time based on timing of the detection of the pointer at the detection point.

Description

technical field [0001] The present invention relates to a technique of moving a pointer by a driving force of a motor so that the pointer stops at a predetermined indicating position so as to coincide with the controlled indicating position of the pointer. Background technique [0002] For example, stepping motors have been increasingly used as a driving force for pointers of gauges of vehicles. The advantage of the stepping motor is that the amount of rotation of the pointer and the indicated position after rotation can be easily defined by the number of input driving pulses. However, since the control of the stepping motor is open-loop control, there are cases where the controlled rotation amount (or rotation position) and the actual rotation amount (or rotation position) differ from each other due to loss of synchronization. [0003] Therefore, when the pointer is driven by the stepping motor, it is necessary to perform pointer return-to-origin processing as required. F...

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Problems solved by technology

However, in the above moving mechanism, since no pushing force in the winding direction is applied to the linear member when the pointer stops at the zero indication position, the current flowing through the coil of the stepping motor does not change, so that it cannot be detected. pointer stop

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