WO1991011678A2

WO1991011678A2 - A method of, and apparatus for, measuring movements

Info

Publication number: WO1991011678A2
Application number: PCT/NL1991/000012
Authority: WO
Inventors: Jan Cornelis Stekelenburg
Original assignee: N.V. Nederlandsche Apparatenfabriek Nedap
Priority date: 1990-01-29
Filing date: 1991-01-29
Publication date: 1991-08-08
Also published as: NL9000205A; WO1991011678A3

Abstract

Method of measuring motion activity, in which a carrier whose motion activity is to be measured, is provided with an apparatus adapted to be read out in contactless manner using an interrogation field and comprising a movement sensor. Measurement occurs during successive fixed intervals, independently of the points in time when readout occurs, and a value representing the motion activity in a plurality of successive intervals, is stored in a storage of the apparatus. For determining the fixed intervals, the apparatus is provided with an internal clock.

Description

Title: A method of, and apparatus for, measuring movements

The invention relates to a method of measuring motion activity, wherein a carrier whose motion activity is to be measured, is provided with an apparatus for measuring motion activity, which apparatus is of the type that can be read out at random points in time in contactless manner using an interrogation field and wherein at readout a measuring result is obtained representing the motion activity in the period prior to the readout.

The invention further relates to an apparatus for measuring motion activity, which apparatus can be read out using an interrogation field and comprises a movement sensor, an activity measuring circuit for processing electric signals supplied by the movement sensor into a measuring result and a modulating device. Methods of measuring movements are known in various applications. It is known, for example, to record the shocks that valuable apparatus or goods are subject to. Further, it is known to measure motion activity in cows, which measurement may provide an indication of estrus when during a succession of movements a reference value for motion activity is exceeded. This use in cows is set forth, for example, in Netherlands patent application 8004704 and US-A-4, 618, 861. These publications describe an activity meter which can be read out by means of an interrogation field, the activity meter being coupled with an electronic identification circuit by which a cow can be identified. The drawback of this known technique is that the movements are recorded in, and read out at the end of, a period that extends between rather arbitrary points in time at which the measured values of the cows are read out. In practice, these two points in time do not define a fixed period. It depends on the operator of the read out apparatus and on the cow's behaviour whether the activity is measured regularly. In the case of estrus detection, it is important to measure when an increased activity occurred. The point is that, as stated above, . increased activity of the cow is an important characteristic of estrus. This characteristic, however, becomes manifest within a period of approximately 5 hours. The theoretically most favourable measuring period should cover these 5 hours. The detection of the period of increased activity is of importance for determining the optimum moment of insemination of the cow, i.e. the moment when the chances of the cow being fertilized are at a maximum. In the known technique, however, it may happen that a cow is not within the interrogation field for a period in excess of 10 hours, for example, which prevents timely detection of increased activity and hence determination of the optimum moment of insemination.

According to EP-A-0087015, this drawback is to some extent overcome in that the measuring apparatus comprises a microprocessor which compares an instantaneous activity value with a reference value. In that case, the measuring apparatus must be provided with a microprocessor that uses relatively much energy, which requires the provision of a relatively large battery. Readout and processing of the data are all done in the microprocessor. As a result, the measuring apparatus is rather complicated.

The object of the present invention is to remove the above-mentioned drawbacks and generally to provide a rugged, effective and accurate method and apparatus for measuring movements.

To that effect, according to the invention, a method of the type described hereinabove is characterized in that the motion activity is measured during predetermined fixed intervals using the apparatus for measuring motion activity and that the measuring results associated with a predetermined number of intervals together with an indication of the specific intervals in which a given measuring result was obtained, are stored in a storage device of the apparatus, the intervals being independent of the points in time when readout takes place. An apparatus for measuring movements is characterized according to the invention by an internal clock circuit which is'continuously in operation and which, each time a predetermined fixed interval has lapsed, supplies a clock pulse causing the measuring result obtained in the preceding interval to be stored in a storage of the apparatus together with an indication of the associated interval.

Hereinafter the invention will be further described, by way of example, with reference to the accompanying drawing of one embodiment of an apparatus for measuring movement.

The single figure schematically illustrates an embodiment of an apparatus 1 that can be attached to an animal, such as a cow, which is arranged to be read out using an electromagnetic interrrogation field generated by a transmitter/receiver 2. The transmitter/receiver has one or more antennae 5 and is connected to a computer or another recording apparatus 3 for recording and storing and optionally processing and/or reproducing the information supplied by the apparatus 1.

The apparatus 1 comprises a section 4 for detecting motion activity and an identification section. In the embodiment shown, the identification section is passive, i.e. the identification section derives the required supply voltage from the interrogation field. The identification section may for instance function in a manner similar to that of the responder described in Netherlands patent application 176404. The identification section comprises a digital circuit 6 in which an identification code is stored, as well as a modulator 7 comprising a receiver circuit attuned to the frequency of the interrogation field, for instance a LC circuit. Via rectifying means 8, the modulator in operation supplies a supply voltage Vdd for the digital circuit and further supplies clock pulses CL to the digital circuit, directly or via a separate oscillator.

In operation the digital circuit supplies the identification code which is used to modulate the signal in the receiver circuit. This modulation may be effected for example by short-circuiting the receiver circuit wholly or partly, in the rhythm of the identification code. Such a modulation can be detected in known manner by the transmitter/receiver. 5 In a responder intended exclusively for identification purposes, only the identification code is supplied to the modulator. In the present case additional information is supplied, as will be explained hereinafter.

The section 4 comprises a sensor 11, which may be a

10 movement and/or acceleration sensor. The sensor 11 may for instance comprise a mercury switch or a piezoelectrical element or a generator such as described for instance in NL-A- 8901720. The signals supplied by the sensor are detected and stored using an activity measuring circuit 12 which may for

15 instance comprise a counter adapted to count the pulses supplied by the sensor. The advantage of using a counter is that it supplies directly digital output signals. In principle, however, the circuit 12 may also be analog and comprise, for instance, a capacitor which is loaded in

20 correspondence with the activity of the cow.

According to the invention, periodically, during a predetermined interval the relevant activity is measured and stored in the activity measuring circuit, independently of the points in time when the apparatus for measuring activities is

25 read out. At the end of such an interval, the activity measured in the interval in question, indicated for instance by the position of a binary counter, is transmitted to a storage. Thereafter, during a subsequent predetermined interval, again a given counter position is reached, which in

30 turn is stored at the end of that interval, etc.

The predetermined intervals may each have a length of 3 hours each, for instance, so that every 24 hours 8 measuring values are obtained, each representing the measured activity in a specific interval.

3.5 For the beginning and the end of the predetermined intervals to be determined, the section 4 comprises a clock circuit 13 connected to a crystal 14. The crystal 14 may f.r instance be of the type that is also used for watches. Since the crystal 14 and the clock circuit 13 must be excited continuously, the section 4 comprises a battery indicated at 5 15, which provides a supply voltage _bat, which is further supplied to the circuit 12 and also to the storage 16 yet to be described.

At the end of each fixed interval, the clock circuit supplies a clock pulse causing the value stored in the 10 activity measuring circuit 12 to be written in a storage 16 in the proper storage location. To that end, the clock pulse is supplied to an addressing device 17, which may for instance comprise a counter and which makes a next location accessible to the information from the activity measuring circuit 12, 15 supplied via the line schematically indicated by line 18. Preferably, the clock pulse at the end of each fixed interval is also used to reset the activity measuring circuit 12, as indicated schematically at 19.

In addition to the activity value measured in a given 20 interval, information is stored in a location which indicates in what interval the measured value stored was measured. To that end, a number may be allocated to each interval.

Advantageously, the storage can be arranged such that the number of locations is equal to the number of fixed intervals 25 per 24 hours. If the fixed intervals were to last three hours each, 8 locations would be required. Further, each location may be associated with a predetermined fixed interval. Thus, location Si may be associated with the first interval of a 24- hour period, location S₂ with the second interval, etc. When 30 an activity value is written in a location, the previous value, which was written 24 hours before, is erased at the same time. Accordingly, the storage in this embodiment always contains all information on the previous 24 hours. This period, however, may be chosen to be shorter or longer, if so ^•35^' desired, with optional adjustment of the number of locations. If so desired, the information stored in the storage may already undergo further processing in the section 4, by determining, each time a new activity value has been written in the storage, the highest value of the activity values stored at that moment and storing this value together with the number of the associated interval in a separate storage section.

To that end, for example, in a simple manner a first value can be written in the separate storage section 20, whereafter that first value is successively compared with the values stored in the other storage sections, using for example a comparator 21. As soon as a higher value is found, it is written in the separate storage section.

This determination of the highest value could be done after each clock pulse or each time the apparatus is read out in an interrogation field. Naturally, it is also possible to read out all information stored in the storage and to have the computer 3 determine the highest value. This, however, requires a longer read-out time Readout may proceed as follows.

When the cow is located within an interrogation field, in addition to the identification code, the highest value measured in the previous eight 3-hour periods is transmitted. This occurs continuously as long as the circuit is within the interrogation field. This information is transmitted periodically in a cycle of 8 times, the value 8 having been selected as an example. In the first seven transmissions, in addition to said information, also the period in which the highest value occurred is transmitted. To that end, for example, the identification code, the highest value (via line 9) and the number of the associated time interval (for example, via line 20) are successively fed to the modulator. At 21 a synchronization line is shown, which initiates the information supply via the lines 9 and 10 after the identification code has been completed. In the eighth and final transmission of the cycle, however, the information transmitted is replaced. In this transmission, not. the allocated number of the period in which the highest value occurred, is transmitted along, but the number of the current, instantaneous period. These data are recorded by the computer connected to the transmitter/receiver and then processed.

After being processed, the data may serve as a starting point for determining estrus and the associated optimum moment of insemination.

The change in the meaning of the information in the cycle of eight transmissions is indicated in this embodiment by a bit especially reserved for this purpose in the code to be transmitted. Through this bit, the computer, which is connected to the transmitter/receiver, obtains information so as to determine the frequency and phase of the internal clock of the measuring apparatus. By virtue of this synchronisation protocol, the computer itself can use an internal clock for each cow, which clock has been coupled to the real clock of the measuring apparatus as accurately as possible through the synchronisation. According as the number of readings-out increases, the accuracy of the synchronisation will increase with it.

Although a relatively simple clock is used in the measuring apparatus, in this manner, using the synchronisation protocol, the location of the fixed intervals can still be determined accurately. By varying a very limited part of the information transmitted, the information can be transferred to the computer efficiently and compactly. This is of importance in view of very brief readout times that sometimes occur. In this embodiment the structure of the information is chosen such that the most relevant information is transmitted first.

In the present invention, the starting-point is to record a measured value and to compare it with the highest value recorded, each time an interval has ended. As stated above, it is possible to determine the highest value at each readout, rather than 8 times per 24 hours. This variant may appropriately be used when readout is not time- critical.

When there is sufficient readout time for the purpose, in addition to the highest value, further all other measured values can be read out, so that a better view of the course of activity can be obtained.

It is observed that hereinabove the invention has been explained with reference to use for detection of estrus in cows. In principle, however, the invention can be used in all situations where it is of importance for movements and/or accelerations of a human, animal or object to be measured. One example that may be mentioned is the measurement of movements and/or accelerations that easily damaged apparatus or other goods are subject to in transit. It is further observed that after the foregoing, various modifications will readily occur to those skilled in the art. Thus, different types of movement sensors and different types of storages with associated addressing circuits can be used. Such modifications are understood to fall within the scope of the invention.

Claims

C AIMS

1. A method of measuring motion activity, wherein a carrier whose motion activity is to be measured, is provided with an apparatus for measuring motion activity, which apparatus is of the type that can be'read out at random points in time in contactless manner using an interrogation field and wherein at readout a measuring result is obtained representing the motion activity in the period prior to the readout, characterized in that the motion activity is measured during predetermined fixed intervals using the apparatus for measuring motion activity and that the measuring results associated with a predetermined number of intervals together with an indication of the specific intervals in which a given measuring result was obtained, are stored in a storage of the apparatus, the intervals being independent of the points in time when readout occurs.

2. A method according to claim 1, characterized in that each time an interval has elapsed, the measuring result obtained in said interval is stored, followed by determining in what interval the measuring result with the highest value occurred; and that at readout the measuring result with the highest value is produced, together with the indication of the associated interval.

3. A method according to claim 2, characterized in that the measuring result with the highest value and the associated interval is not determined until at readout.

4. A method according to claim 1, characterized in that an apparatus is used provided with an identification code detectable by means of an interrogation field and that at readout both the identification code and the measuring result associated with at least one fixed interval are read out.

5. A method according to claim 1, characterized in that at readout it is also determined in what fixed interval readout occurs.

6. A method according to claim 5, characterized in that t result of the readout is fed to a processing device which comprises an internal clock, and that on the basis of the information regarding the intervals during which a readout occurred, the internal clock is synchronized with the predetermined fixed intervals.

7. An apparatus for measuring motion activity, which apparatus can be read out using an interrogation field, and comprises a movement sensor, an activity measuring circuit processing electric signals supplied by the movement sensor and a modulating device, characterized by an internal clock that is in operation continuously, and that produces a cloc pulse each time a predetermined fixed interval has lapsed, said clock pulse causing the measuring result obtained in t preceding interval to be stored in a storage of the apparat together with an indication of the associated interval.

8. An apparatus according to claim 7, characterized by an identification section that can be read out using an interrogation field, a binary identification code being sto in said identification section.

9. An apparatus according to claim 7, characterized by me for comparing with each other the measuring results stored the storage and determining the highest value thereof and b separate storage portion in which the highest value is stor together with an indication of the associated fixed interva

10. An apparatus according to claim 7, characterized in th the clock pulse resets the activity measuring circuit.

11. An apparatus according to claim 7, characterized in t the clock circuit is provided with a watch crystal element.