JPH05196454A - Detecting device for absolute position - Google Patents

Abstract

PURPOSE:To obtain an absolute position data at an optional timing apart from sampling cycle. CONSTITUTION:A data change amount detection means 2 outputs data change amount X=PSf-PS1 based on the absolute position data (PSf, PS1) outputted from an absolute position detector 1, and a speed data generating means 3 outputs a speed data V by using the data change amount X and sampling cycle Ts. A time counting means 4 outputs the passage time Tc from sampling start timing to inputting of position data output request signal, and further a moving amount arithmetic processing means 5 processes the speed data V and passage time Tc to find out an estimated moving amount data (VXTc) and finally a summing means 6 adds the estimated moving amount data (VXTc) to the absolute position data PS1 to output the position data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absolute position detecting device for detecting the position of a moving body.

[0002]

2. Description of the Related Art In a control device such as a numerically controlled machine tool or an industrial robot, an absolute position detecting device is used to detect the absolute position of a moving body. In the conventional absolute position detection device, an absolute position of a moving body is detected at each sampling cycle using an absolute position detector including an absolute encoder or a combination of a resolver and a gear, and position data is output.

[0003]

However, the conventional absolute position detecting device cannot obtain the position data of the moving body between the samplings. Even so, if the moving amount of the moving body is not so large, there is no particular problem in using the moving body in the control device. However, there is a limit to shortening the sampling cycle, and when the moving amount of the moving body increases, the error of the position data output at each sampling cycle becomes large, and the control of the control device that uses the output of the absolute position detection device. The operation is adversely affected. Therefore, in such a case, the conventional control device synchronizes the control operation with the sampling cycle of the absolute position detecting device, but the control operation is limited to the sampling cycle.

An object of the present invention is to provide an absolute position detecting device which can output absolute position data at any time with high accuracy regardless of the sampling cycle.

[0005]

As shown in the block diagram of FIG. 1, an absolute position detecting device of the present invention includes an absolute position detector 1 for outputting absolute position data of a mobile unit at each sampling cycle, and an absolute position detector 1. A change amount detecting means 2, a speed data generating means 3, a time counting means 4, a movement amount calculating means 5,
And adding means 6. Data change amount detection means 2
Detects the amount of data change between the current absolute position data output from the absolute position detector 1 and the previous absolute position data output from the absolute position detector. The speed data generating means 3 generates speed data based on the data change amount detected by the data change amount detecting means and the sampling cycle. The time counting means 4 counts the time from the start of sampling of each sampling to the input of the position data output request signal. The moving amount calculating means 5 calculates the predicted moving amount data of the moving body from the speed data and the time counted by the time counting means, and the adding means 6 adds the absolute position data and the predicted moving amount data to output the position data. The position data of the moving body at the time when the request signal is input is output.

[0006]

According to the present invention, in order to obtain the position data of the moving body between the sampling of the absolute position detector 1, the data change amount detecting means 2 and the speed data generating means 3 first perform the immediately preceding sampling and the current time. The rate of data change between the sampling and the velocity data V is obtained from the difference X = PSf-PS1 between the immediately previous absolute position data PSf and the current absolute position data PS1, the sampling period Ts, and the necessary constant K (V = K.X / Ts). Then, the time counting means 4, the movement amount calculation means 5, and the addition means 6 obtain the predicted movement amount data (V × Tc) from the elapsed time Tc from the sampling start time when the current sampling is started and the speed data V. , This predicted movement amount data (V × T
c) is added to the absolute position data PSl of this time to obtain the position data. As described above, in the present invention, the predicted movement amount data of the moving body between the samplings is obtained and the data between the samplings is complemented, so that the absolute position data of the moving body between the samplings can be obtained almost accurately.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows an embodiment in which the invention of claim 1 is implemented by hardware, that is, a circuit configuration. The absolute position detector 1 is a known absolute position detector including an absolute encoder, a combination of a resolver and a gear, and the like, and outputs absolute position data measured for each sampling. Further, in this embodiment, the absolute position detector 1 outputs the latch signal LP synchronized with the sampling cycle. Of course, the latch signal LP may be obtained from another signal generating means. The absolute position data output from the absolute position detector 1 is input to the data change amount detecting means 2. The data change amount detecting means 2 of this embodiment is composed of first and second latch circuits 21 and 22, a subtractor 23 and an inverter 24. The first or previous absolute position data PSf is latched in the first latch circuit 21 by the rising edge of the first or previous latch pulse LP, and then the first latch circuit 21 is inverted by the rising edge of the inverted latch pulse inverted by the inverter 24. Is latched by the second latch circuit 22. As a result, the subtractor 23
Is the difference between the current absolute position data PSl latched by the first latch circuit 21 and the last absolute position data PSf latched by the second latch circuit 22, that is, the data change amount X = PSf-PSl. , Speed data generating means 3
Output to.

The speed data generating means 3 has a data change amount X
Then, the velocity data V is calculated from the sampling period Ts and
It outputs to the movement amount calculation means 5. In this embodiment, the speed data generating means 3 comprises a ROM 31. ROM3
1 stores a calculated value of speed data V = K · X / Ts according to the expected data change amount X, and the corresponding speed data V is output every time the data change amount X is input. To be done. Here, K is a constant. It is needless to say that the speed data generating means 3 may be composed of a calculator for calculating the speed data V = K · X / Ts.

The time counting means 4 is reset at the rising edge of the latch pulse LP, starts counting time, and outputs a position data output request signal RS from a position data output request signal generating means provided in a controller (not shown). It is constituted by a timer 41 that stops counting the time (at the falling edge of RS) and outputs the counting time Tc to the movement amount calculating means 5 when is input.

Speed data V from the speed data generating means 3
Based on these inputs, the moving amount calculating means 5 to which the time Tc from the time counting means 4 is input and the predicted moving amount data Y = (V * Tc) of the moving body is output to the adding means 6. To do. In this embodiment, the movement amount calculating means 5 is a multiplier 51.
Composed of.

The predicted movement amount data Y obtained by the movement amount calculation means 5 is input to the addition means 6 and added to the present absolute position data PSl. The adding means 6 of this embodiment comprises an adder 61 and a latch circuit 62. The addition result PS = PSl + V · Tc added by the adder 61 is
The position data output request signal RS is latched and output by the latch circuit 62 at the trailing edge of the signal RS.

The operation of the above embodiment is shown in FIG. In FIG. 3, the horizontal axis is time, and the interval (eg, t1 to t2) of each time is the sampling period,
The vertical axis shows absolute position data. P in this figure
Sφ corresponds to the previous absolute position data PSf, and PS1 corresponds to the current absolute position data PSl. In the conventional method, only absolute position data indicated by white circles in FIG. 3 can be obtained.

Although the above embodiment is an example in which the present invention is implemented by hardware, the present invention can also be implemented by software using a microcomputer. The configuration when implemented by software is the same as that shown in FIG. FIG. 4 is a flow chart showing an algorithm for carrying out the present invention with the configuration of FIG. 1 using a microcomputer. In the configuration of FIG. 1, the data change amount detecting means 2, the speed data generating means 3, the time counting means 4, the movement amount calculating means 5 and the adding means 6 are realized by software.

[0014]

According to the present invention, when a position data request signal is input, predicted movement amount data of a moving body between samplings is obtained and data between samplings is complemented. It is possible to accurately obtain the absolute position data of the moving body between the couplings.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining a configuration of the present invention.

FIG. 2 is a diagram showing an example of the present invention.

FIG. 3 is a diagram for explaining the operation of the embodiment.

FIG. 4 is a flowchart showing an algorithm when the invention of claim 1 is carried out using a microcomputer.

[Explanation of symbols]

1 ... Absolute position detector, 2 ... Data change amount detecting means, 3 ...
Speed data generating means, 4 ... Time counting means, 4 '... Elapsed time counting means, 5 ... Moving amount calculation means, 6 ... Addition means, 2
1, 22, 62 ... Latch circuit, 23 ... Subtractor, 31 ... R
OM, 41 ... Timer, 51 ... Multiplier, 61 ... Adder.

Claims (1)

[Claims] 1. An absolute position detector that outputs absolute position data of a mobile object at each sampling cycle, absolute position data output from the absolute position detector, and an absolute position immediately before output from the absolute position detector. A data change amount detecting means for detecting a data change amount between data, a speed data generating means for generating speed data based on the data change amount and the sampling period, and a position data output request from the sampling start point of each sampling Time counting means for counting the time until a signal is input, movement amount calculating means for calculating predicted movement amount data of the moving body from the speed data and the time counted by the time counting means, and the absolute position The data and the predicted movement amount data are added to output the position data of the moving body at the time when the position data output request signal is input. Absolute position detection device comprising comprising a adding means for.