ADAPTIVE METHOD FOR MEASURING MOVEMENTS

Abstract

The invention can be used for determining absolute movements of objects. The problem to be solved consists in increasing the accuracy of the measurement of movements of an object when obstacles are present in the trajectory of motion thereof by eliminating error accumulation in the positioning of signal sources. A transducer is mounted on an object, separate sources of uniquely coded signals are used and/or groups of sources of a uniquely coded signal are formed, the separate sources of uniquely coded signals and/or formed groups of sources of a uniquely coded signal are placed randomly along the trajectory of movement of the object at any distance between any two consecutively mounted separate sources of a uniquely coded signal and/or between any two formed groups of sources of a uniquely coded signal, said distance not exceeding the measurement range of the transducer, a signal is directed at the moving object having the transducer, an output signal from the transducer regarding the position of the separate sources of uniquely coded signals and/or groups of sources of a uniquely coded signal is received, and the position of the object is determined.

Claims

1. An adaptive method for measuring movements, wherein a transducer is mounted on an object, separate sources of a uniquely coded signal are used and/or groups of sources of a uniquely coded signal are formed, the separate sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal formed are arranged randomly along an object's motion path at any distance between any two successively installed separate sources of a uniquely coded signal and/or between any two formed groups of sources of a uniquely coded signal not exceeding the transducer measurement range, the signal is directed on the moving object having the transducer, the output signal indicating the position of separate sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal is received from the transducer, and the object position is determined.

2. The method according to claim 1, wherein groups of sources of a uniquely coded signal are obtained by changing the number of signal sources and/or changing the distance between any two signal sources and/or changing the types of signal sources used.

3. The method according to claim 1, wherein separate sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal are positioned along the object's motion path, at an equal distance between any two successively installed separate sources of a uniquely coded signal and/or between any two formed groups of sources of a uniquely coded signal not exceeding the transducer measurement range.

4. The method according to claim 1, wherein chips, code carriers, tags being a part of the radio frequency identification system are used as separate sources of a uniquely coded signal.

5. The method according to claim 1, wherein magnets, light sources, heat sources, any kinds of radiation sources, kinetic energy sources, pressure sources, ultrasonic waves, and materials with inductive and/or capacitive physical properties are used as signal sources for forming groups of signal sources.

6. The method according to claim 1, wherein Hall sensors, photo cells, magnetostriction transducer, inductive and capacitive transducers, radio frequency transducers, radiation transducers, pressure transducers are used as transducers.

7. The method according to claim 1, wherein a processor and a connected or a built-in antenna, radar, reading/recording head are used as transducers.

8. The method according to claim 1, wherein the numbers of separate sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal are determined by the output signal from the transducer.

9. The method according to claim 1, wherein a coordinate grid is additionally built for determining the position of an object, the object is positioned with determining its absolute coordinate, and additions and exclusions of sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal, changes in the location of sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal in space are tracked with automatic adjustment of the table showing space location of separate source of a uniquely coded signal and/or a group of sources of a uniquely coded signal.

Description

[0023] FIG. 1 shows a system that implements the method as claimed while moving an object along a path without obstacles;

[0024] FIG. 2 shows an object being moved along a path with an obstacle.

[0025] An adaptive method for measuring movements is implemented using the system shown in the figure containing a transducer 1, located on an object 2, and groups 3 of sources 4 of a uniquely coded signal, by changing the number of signal sources 4 and/or changing the distance between any two signal sources 4 and by changing the types of the sources used. Separate sources of a uniquely coded signal (chips, tags, code carriers) can also be used.

[0026] For example, an object 2 is provided with a magnetostriction linear movement transducer having a movement measurement range a and being used as transducer 1. Groups 3 of signal sources 4uniquely coded magnetsare placed along the object's 2 motion path at any distance from each other, not exceeding the transducer measurement range a. Thus, there is always at least one group 3 of sources 4 of a uniquely coded signal or two magnets with unique distance therebetween on the path section of length a.

[0027] Let's consider the case when, in each path section of length a, groups 3 of uniquely coded magnets are used, having the same number of magnets, but a variable distance therebetween. That is, in the first path section of length a the magnets of the group 3 are positioned at a distance from each other to form the first unique set, in the second path section of length a the magnets of the group 3 are positioned so that the rightmost magnet is moved away by a distance of 24, in the third path section of length a the magnets of group 3 are positioned so that the rightmost magnet is moved away by a distance of 34, and so on. As a result, in any object's motion path section of length a opposite to the transducer sensitivity zone, there is a non-repeating (unique) combination of signal sources 4 within the group 3 located at distances therebetween with non-repeating values, which allows for clear identifying the object 2 position and determining its movement (FIG. 1).

[0028] Also, the magnets of the group 3 can be positioned so that the distance between them remains the same, but their number changes, that is, in the first path section of length a two magnets can be placed and in the second path section of length athree magnets can be placed, etc. In this case, in any path section of length a opposite to the sensitivity zone of the movement transducer 1, a non-repeating combination of signal sources 4 of group 3 will be located, which allows for clear identifying the object 2 position and determining its movement.

[0029] It is also possible to place the magnets of the group 3, when both the number of magnets and the distance between any two magnets change, that is, in the first path section of length a a group 3, for example, with two magnets at a distance 4 therebetween is placed, in the second path section of length a group 3 with three magnets at a distance 2 therebetween is placed, etc. In this case, in any path section of length a opposite to the sensitivity zone of the transducer, a non-repeating combination of signal sources 4 of the group 3 will be located, which allows for clear identifying the object position and determining its movement.

[0030] This method can be used when an obstacle 5 difficult to remove is present on the object's 2 path, the size of the obstacle not exceeding the measurement range of the transducer. If before the presence of an obstacle the groups 3 of sources 4 of a uniquely coded signal were optimally positioned, that is, at a maximum distance from each other, then in the presence of an obstacle 5, the next group 3 of sources 4 of a uniquely coded signal is placed in front of the obstacle 5, and the subsequent group 3 of sources 4 of a uniquely coded signal is placed already behind the obstacle 5, for example, at the maximum distance from the previous group 3.

[0031] Groups 3 of sources 4 of a uniquely coded signal are randomly placed on each path section of length a. When moving the object 2 along the path with groups 3 of sources 4 of a uniquely coded signal arranged, the movement transducer 1 outputs the position value for each said group 3, opposite which the object 2 with the movement transducer 1 mounted thereon is located. At the time point the object's first motion is started the processing equipment receives information about the object position coordinate at the starting point. This coordinate is taken as the zero of the coordinate system. During the progressive motion of the object in the direction of increasing its coordinates, set groups 3 of sources 4 of a uniquely coded signal come into the active zone of the transducer. In this case, at the moment when the successive group 3 of signal sources 4 enters the transducer active zone, according to the placement conditions for the group 3 of signal sources 4 the previous group 3 of signal 4 sources will always be present in the transducer active zone. Thus, given the absolute coordinate of the previous group 3 of signal sources 4, the absolute coordinate of the next group 3 of signal sources 4 is calculated. The resulting values are transmitted to the processing equipment, which, after receiving information about the object position relative to each specific group 3, calculates the absolute position of the object along the path. If it is necessary to measure the absolute value of the object position after switching the equipment power supply off, the obtained values of the position for each group 3 of signal sources 4 should be stored in the non-volatile memory of the processing equipment.

[0032] Also by the output signal from the movement transducer it is possible to determine the numbers of the groups 3 of signal sources 4, the effect of which was exerted on the transducer 1, as well as any other parameters of said groups 3, if needed.

[0033] In addition, the pre-formed groups of sources of a uniquely coded signal and/or separate sources of a uniquely coded signal from several path sections of length a can be randomly reversed, if necessary, to ensure the location of at least one separate source of a uniquely coded signal and/or one such group at a distance not exceeding the transducer measurement range. Also, if necessary, any number of additional separate sources of a uniquely coded signal and/or formed groups 3 of sources 4 of a uniquely coded signal can be added in any path section of length a. The adaptability of the suggested method for measuring movements allows for increasing the measurement accuracy while excluding its dependence on the accuracy of the signal sources positioning. In its turn, the absence of the need to locate separate sources of a uniquely coded signal and/or groups 3 in a certain order contributes to the freedom of their arrangement, allowing for performing this arrangement simultaneously by several separate groups, which significantly reduces the deployment time of the object measurement system.

[0034] The extension of the distance to which it is possible to move an object can be calculated as follows. For example, a transducer by Balluff GmbH is used as magnetostrictive linear movement transducer, the nonlinearity of which is 30 m, the measurement range is 4500 mm. If this transducer and a group with two signal sources are used, the distance change therebetween making 31 m at each path section, and the minimum required distance between signal sources should be at least 60 mm, it is possible to obtain:

[00001]$\begin{array}{cc}\frac{\frac{4500}{2}-60}{0.03+0.001}=70645& \left(1\right)\end{array}$

unique positions of signal sources.

[0035] Thus, the total measurement range when using groups with two sources of a uniquely coded signal is:

450070645=317902500 mm=317.9 km(2)

at a repeatability of 30 m.

[0036] Repeatability is a characteristic of the quality of measurement results, which reflects the degree of approximation of one to another by the results of repeated measurements for the same physical quantity, carried out under the same conditions.

[0037] As a result, an adaptive method for measuring the movements of an object allows for increasing the accuracy when measuring the movements of an object with a significant increase in the movement distance and in the presence of obstacles difficult to remove along the object's path. This greatly simplifies the process of positioning signal sources arranged into uniquely coded groups before they are placed along an object's motion path, which reduces the labour required when implementing the method in general and improves its usability.

[0038] It also increases the speed of determining the object position and its movement throughout the production area, which ensures an increase in the efficiency of the production process as a whole. In addition, to measure the movements in cases with passive power sources, it is necessary to provide power to only one transducer mounted on the object, which also simplifies the measurement method.

[0039] The advantage of the adaptive method is the ability to automatically build a coordinate grid consisting of separate sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal for determining the position of an object by passing an object through all or a part of said signal source variants. With this purpose the absolute coordinate of any separate source of a uniquely coded signal and/or a group of sources of a uniquely coded signal are determined along the object's path, the distance between successively located separate sources of a uniquely coded signal or groups of sources of a uniquely coded signal is calculated relative thereto, the absolute coordinates of each separate source of a uniquely coded signal and/or a group of sources of a uniquely coded signal in space are automatically calculated, provided that any two successive separate sources of a uniquely coded signal and/or two successive groups of sources of a uniquely coded signal are located within the transducer measurement range. Thus, a table showing space location of separate source of a uniquely coded signal and/or a group of sources of a uniquely coded signal is automatically generated, being the basis the object to be positioned on.

[0040] Moreover, when using the adaptive method, it becomes possible to track location changes of sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal in space without stopping positioning, as well as increasing the path and distance of positioning by adding new sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal on the object's motion path. The system implementing this method continues its operation in the case of individual or mass loss of separate sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal, if the space location conditions for signal sources and/or groups of signal sources are not violated. In other words, when using the adaptive method, two functions are simultaneously and continuously performed: positioning an object with determining its absolute coordinate, and tracking additions and exclusions of sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal, and changes in the location of sources of a uniquely coded signal and/or groups of sources of a uniquely coded signal in space with automatic adjustment of the table showing space location of separate source of a uniquely coded signal and/or a group of sources of a uniquely coded signal, if the necessary conditions for their location are not violated.

[0041] It is also important that for the implementation of the method different signal sources, transducers and the corresponding equipment for processing the output signal can be used, which makes it universal.