JP2546346B2 - Position sensor compensation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for compensating a sudden change in a position sensor when a detection signal value is suddenly displaced by a sensor or the like for detecting a rotation angle of a motor. The present invention relates to a sudden change compensation processing method for keeping a detected signal value after change continuous and linear.

B. SUMMARY OF THE INVENTION In the present invention, in the sudden displacement compensation processing method for a position sensor when a detection signal value is suddenly displaced by a sensor or the like for detecting a rotation angle of a motor, the fluctuation rate of the detection signal exceeds a predetermined level. It is equipped with a sudden change detection circuit that determines that the detection signal and a compensation calculation circuit that corrects the detection signal after the sudden change by the amount of the sudden change, and keeps the detection signal value continuous and linear, thereby not limiting the measurement range and improving accuracy. It provides a technology that does not reduce the number of rotations, does not have to be multi-rotation type, does not need to use gears in multiple stages, has few errors, saves space, maintains signal continuity, and provides stable control. It is a thing.

C. Conventional technology There are various types of sensors that detect the rotation angle of a motor, such as potentiometers, resolvers, and encoders, but all of them cannot detect linearly until the motor rotates indefinitely, and detect when a certain finite rotation is reached. The signal changes suddenly.

FIG. 8 is an explanatory diagram showing a general sudden change in the detected angle, in which the abscissa indicates the elapsed time t and the ordinate indicates the detected signal value x. In the figure, P1, P2 ... Are sudden change points, and Δx1, Δx2 ... Are respective sudden change amounts. When this sudden change occurs, the control system that performs the position control by the detection signal is the same as the sudden change in the set value or the follow-up value, and the control becomes uncontrollable. Therefore, conventionally, the device is used in a range where no sudden change occurs, but it has been dealt with by expanding the measuring range by using a multi-rotation type sensor or gear.

D. Problems to be Solved by the Invention However, the above conventional coping methods have the following drawbacks.

(A) When the measurement range is limited, the range is 0-10 of the signal.
This means 0%, and the accuracy of the signal is relatively reduced.

(A) The multi-rotation type sensor is large and requires a lot of space for installation.

(C) If a gear is used, an error due to backlash, play, etc. becomes large, and an assembling space also becomes large.

The present invention was conceived in view of such a problem, does not limit the measurement range, maintains accuracy, does not need to use multiple gears in multiple rotations, does not need to use gears in multiple stages, has little error, and is space-saving. It is an object of the present invention to provide a sudden change compensation processing method for a position sensor, which does not need to be originally provided, maintains signal continuity, and enables stable control.

E. Means for Solving the Problems In the present invention, a means for solving the above problems is a sudden change compensation processing method for linearly compensating a detection signal of a position sensor for detecting a rotation angle position of a motor. In the above, a sudden change detection circuit for determining that the variation rate of the detected signal exceeds a predetermined level and a compensation calculation circuit for compensating the detected signal value after the sudden change by the sudden change amount are provided, and the detected signal value is continuously measured. It is based on the sudden change compensation processing method of the position sensor that keeps the linearity.

F. Action The present invention, as shown in FIG. 1 shows the basic principle of the present invention,
The continuity of the detected values is maintained by detecting the sudden change of the detection signal and also obtaining the amount of change (change amount) and subtracting this value from the detected value after the change.

The sudden change in the signal is detected by the sudden change detection circuit. For the sudden change detection circuit, predetermined threshold values are set in advance in both the positive and negative directions, and it is determined whether or not the variation rate of the detection signal, that is, the variation amount within a fixed time exceeds the level. "Sudden"
If it is determined that the fluctuation amount is a sudden change amount, the compensation calculation circuit corrects the detection signal value after the sudden change based on the sudden change amount. For example, with respect to the detection signal value Ha after the first sudden change shown in FIG. 1, by correcting only the first sudden change amount Δx1, a signal value Hn that continues to that time is obtained, and after the second sudden change. With respect to the detection signal value Hb of, the second sudden variation Δx2 is further modified to obtain continuous signal values Hn. In this way, by adding each sudden change amount for each sudden change and setting the total correction amount as Δx1 + Δx2 +, a continuous signal value Hn is always obtained. This also applies to the opposite direction (-t side).

G. Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of the sudden change compensation circuit of the present invention. In the figure, the sudden change compensation circuit is composed of a plurality of registers 1a to 1d, a sudden change detection circuit 2, and a compensation calculation circuit 3.

Each time the detection signal is input from the sensor 4, the register 1a holds the signal, and moves the signal held until then to the next register 1b. Therefore, the current signal value is always held in the register 1a, and the previous signal value is held in the register 1b. The brass threshold of the sudden variation per unit time is set in the register 1c, and the negative threshold is set in the register 1d.

The sudden change detection circuit 2 includes two comparison circuits 21 and 22, and the compensation calculation circuit 3 includes a variation amount calculation circuit 31, a compensation amount setting circuit 32, a compensation amount calculation circuit 33, and a signal value calculation circuit 34. These actions will be described later.

FIG. 3 is an explanatory diagram of the sudden change compensation processed by the sudden change compensation circuit. As shown in the figure, the actual sudden change does not occur instantaneously but occurs while a finite time T elapses. Therefore, a time Δt that is smaller than the time T required for the sudden change
The detection signal as the input cycle from the sensor
If it is taken into 1a, it is possible to calculate a continuous signal value Hn from the current signal value xn, the previous signal value xn-1 and the two-previous signal value xn-2.

FIG. 4 is a flow chart showing a calculation process for compensating the sudden change of FIG. 3 by the sudden change compensating circuit of FIG.

The detection signal is input to the register 1a from the sensor 4 of FIG. 2 at each predetermined timing Δt, and as a result, the current signal value xn is always held in the register 1a and the previous signal value xn− is stored in the register 1b. 1 is reserved. Fluctuation calculation circuit 31
Outputs the fluctuation amount F by subtracting the previous signal value xn-1 from the current signal value xn, as shown in the first stage of the flow. This fluctuation amount F is input to the sudden change detection circuit 2, and when it is positive, it is compared with the threshold value D1 of the register 1c by the first comparison circuit 21, and when it is negative, the second value is detected. Comparison circuit
At 22 it is compared with the threshold D2 of register 1d. As a result of comparison, when the absolute value of the fluctuation amount F exceeds each level,
The fluctuation is determined to be a “sudden change”, and thereafter, the fluctuation amount F is processed as a sudden change amount G. On the other hand, the calculation result of the fluctuation amount calculation circuit 31 is input to the compensation amount setting circuit 32 and stored as the previous fluctuation amount I. The compensation amount setting circuit 32 may be a holding circuit, but a register for the signal value xn-2 before the second is provided, and
It may be an arithmetic circuit for calculating = xn-1−xn-2.

Now, when the sudden change detection circuit 2 determines that "a sudden change", the compensation amount calculation circuit 33 adds the output of the variation amount calculation circuit 31 and the output of the compensation amount setting circuit 32 to the calculation J = GI. The compensation amount J is calculated by. The calculated compensation amount J is input to the signal value calculation circuit 34, and the signal value calculation circuit 34 calculates the compensation amount J.
And the signal value Hn after compensation is output by the calculation Hn = xn-J for adding the current signal value xn.

If it is not determined to be “abrupt change”, these calculations may be passed or J = 0 may be processed.

Each of FIGS. 5 to 7 is an explanatory diagram showing an example in which the above-mentioned sudden change compensation circuit of the present invention is applied to bumpless, which is one of position control by a servo motor. First, the fifth
The figure is a block diagram showing normal bumpless control, in which 51 is position setting means such as a potentiometer, 52 is a driver, 53 is a motor, and 54 is a position sensor attached to the motor 53. In such a servo system, if the detection signal of the position sensor 54 suddenly changes while the motor 53 follows the position setting means 51, the continuity of the detection signal becomes uncertain and the range of position control becomes inaccurate. Therefore, bumpless control will not be achieved. Therefore, as shown in FIG. 6, bumpless control can be performed by adding the amount of sudden change Δx from the position sensor to the position setting output. FIG. 7 is a block diagram showing an application example of the present invention. FIG. 71 shows position setting means.
72 is a driver, 73 is a motor, and 74 is a position sensor attached to the motor 73. The sudden change compensation circuit 75 according to the present invention is
When the detection signal PV from the position sensor 74 is fed back to the front stage of the driver 72, the detection signal PV is taken in and the sudden variation Δx (the compensation amount J) is further set to the position setting means in the front stage.
It is connected so that it can be added to the 71 side. This is the same as if the detection signal PV from the position sensor 74 and the position setting signal SP from the position setting means 71 were suddenly changed at the same time, and the relationship of PV = SP is maintained even during the sudden change and bumpless control is performed. It will be possible.

The sudden change compensation processing method of the above embodiment has the following advantages.

(A) Since the measuring range is not limited, the accuracy does not decrease.

(B) Since it does not need to be a multi-rotation type, it does not take up space.

(C) Since it is not necessary to use gears in multiple stages, there is little error due to play or play, and space is not required.

(D) Since the signal continuity is maintained, the control is stable.

H. Effects of the Invention As described above, according to the present invention, the measurement range is not limited, the accuracy is maintained, the multi-rotation type is not required, and the gears do not have to be used in multiple stages. It is possible to provide a position sensor sudden change compensation processing method that does not need to be originally provided, maintains signal continuity, and obtains stable control.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the basic principle of the present invention, FIG. 2 is a configuration diagram of an embodiment of the present invention, FIG. 3 is an explanatory diagram of the embodiment, and FIG. 4 is a sudden change compensation process of the embodiment. A flow chart, FIGS. 5 to 7 are explanatory views of an application example of the present invention, and FIG. 8 is an explanatory view of a general detection angle sudden change. 1a to 1d ... Register, 2 ... Temporary change detection circuit, 3 ... Compensation calculation circuit, 4 ... Position sensor, 21,22 ... Comparison circuit, 31
...... Variation amount calculation circuit, 33 …… Compensation amount calculation circuit, 34 …… Signal value calculation circuit.

Claims (1)

(57) [Claims] 1. A sudden change compensation processing method for continuously and linearly compensating a detection signal of a position sensor for detecting a rotational angle position of a motor, wherein a judgment is made that a variation rate of the detection signal exceeds a predetermined level. A position sensor sudden change compensation processing method, comprising: a change detection circuit; and a compensation calculation circuit that corrects a detection signal after a sudden change according to a sudden change amount, and keeps the detection signal value linear.