A Nulling Algorithm for Pointer Meter

Abstract

The invention relates to a zero-returning algorithm of a pointer instrument. The specific zero-returning process is as follows: Step 1: Assume that the pointer is located at the farthest position from the pointer to the zero-returning mechanical limit when the instrument is working; Quickly rotate X° in the bit direction, step 3: take the current position as the imaginary zero position, and the stepper motor rotates from the remote mechanical limit to the zero return mechanical limit to be forward rotation; step 4: the stepper motor returns to zero in multiple times Rotate in the direction of the mechanical limit, and each time lasts only a few milliseconds; Step 5: Set the stepper motor to rotate from the zero mechanical limit to the remote mechanical limit to forward rotation. If the current position is set to the zero position of the scale, it is completed to zero. The invention makes it possible to quickly and accurately return to the same position no matter where the initial position of the pointer of the meter is, thereby solving the problem of zeroing errors caused by different initial positions of the pointers, and ensuring that the meter can return to zero after being powered on under any circumstances. use. This algorithm has the advantages of fast zeroing speed, good consistency and small error.

Description

technical field [0001] The invention relates to a pointer instrument driven by a stepping motor, in particular to an automobile pointer instrument using a special zero-returning algorithm. Background technique [0002] Stepper motors have the advantages of small size, low cost, and high reliability, and are very suitable for driving pointer instruments in automotive instruments. With the popularization of mass production of civilian vehicles, the technology and application of stepping motors are becoming more and more mature, and they have entered thousands of households unconsciously. [0003] However, the stepper motor itself cannot sense the rotational position and must be calibrated to zero before use. The accuracy of zero calibration directly determines the accuracy of the pointer instrument, thus affecting the use of the instrument. The stepper motor driver chip comes with zero-return and stop-return instructions. Due to its slow return to zero speed, in practical a...

AI Technical Summary

Problems solved by technology

And many algorithms will cause obvious pointer jitter

In addition, once the indicator does not stop near the zero position of the scale due to sudden power failure or other factors during use, when the power is turned on again, because the pointer is far away from the mechanical limit of zero return, the position where it stops after hitting a wall and rebounding, There is an imperceptible small deviation from the position where the initial position is near the zero position of the scale and bounces off the wall. This deviation will be greatly amplified by the next zero return and stop zero return commands, causing the pointer of the meter to deviate from the zero position of the scale. The error sometimes up to about 2°

Faced with this situation, it is generally necessary to turn off the power of the meter and turn it on again to let the stepper motor return to zero before returning to normal, which seriously affects the use of the pointer meter

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