A DEVICE AND METHOD FOR MILKING ANIMALS

Abstract: The invention concerns a device and a method for milking of animals whereby the teatcups are mounted on a milkrack and the milkrack can be moved with a positioning system in such a way that the teatcups are brought one after the other under a teat of the animal, whereafter the teatcups are brought upwards around the teat. For controlling the movements of the positioning system, a sensor system is used that can follow the position of a reference teat. In accordance with the invention, the detection field of the sensor system is movable in regard to the milkrack in a direction similar to the breadth direction of the animal to be milked.

Description: A device and method for milking animals The invention concerns a device according to the preliminary part of claim 1. Such a device is known from EP 0323875. In the known device the position of one of the teats is detected by the sensor system 15 with the sensors 16 whereafter the positioning means bring the teatcups one after the other under the respective teats and attach the teatcups around the teats . The disadvantage of the known device is that it is sometimes unclear in the controlsystem which of the front teats has been detected by the sensorsystem. Another disadvantage is that the detected teat can be brought outside the most sensitive part of the detectionfield when a teatcup is brought under a teat . The invention aims to remove these disadvantages and thereto the sensorsystem comprises sensors for generating a detectionfield in at least two positions viewed breadthwise. By bringing the detection- field in two breadth positions the frontteats will be irradiated from at least two directions so that additional position- information is generated and the position of both frontteats can be determined. Also one of the frontteats can remain in the most sensitive part of the detectionfield during moving of the positioning means breadthwise when a teatcup is positioned under a teat . In accordance with an embodiment the sensors are movable breadthwise relative to the positioning means . By making the sensors movable relative to the positioning means the detectionfield is moved in an easy way and simple sensors can be used. Also the movement can then be quick, so that the position of the cow and the teats is only little changed. The invention also comprises a method in accordance with the preliminary part of claim 4. This method is known from the earlier mentioned document. The disadvantage of the known method is that it is not always clear from which frontteats the position is determined by the sensors. In accordance with the invention for determining the position of a frontteat the detection- field is generated in at least two positions viewed breadthwise relative to the frontteats. By moving the detectionfield the sensors can generate additional position information, so that the position of a frontteat can be determined more accurately. Also the invention comprises a method in accordance with the preliminary part of claim 5. This method is known from the earlier mentioned document. In the known method during attaching of the teatcups the movements of the cow are followed by means of sensors. This is done by following the movements of one of the frontteats, after this frontteat has been brought in the detectionfield. During the positioning of a teatcup under a teat which is not followed by the sensors the position of the teat that has been followed will change in regard to the positioning means and also in regard to the detectionfield. This causes the teat to move outside the most sensitive part of the detectionfield which results in a deteriorated measuring signal, which is a disadvantage. In accordance with the invention during the attachment the detectionfield is moved breadthwise relative to the positioning means so that one of the two frontteats remains in the more sensitive part of the detectionfield. This prevents the earlier mentioned disadvantage . The invention is hereafter illustrated with help of an embodiment with a drawing wherein figure 1 shows a schematically topview of a milking parlour for cows, figure 2 shows a detail in topview from the sensorsystem shown in figure 1 for the detecting of the position of a teat, and figure 3 shows the sensorsystem of figure 2 in sideview. In the various figures the similar parts have been provided with similar numbers . In figure 1 a topview of a milking parlour is shown wherein a to be milked animal A has been indicated schematically. The attachment of teatcups around the teats is executed in hereafter described way with a positioning and attachmentsystem under control of a controlsystem, such a system is known under the name milkrobot. The following of the position of the teats during attachment is thereby important, whereby the invention inter alia concerns the sensorsystem used. Teatcups 6 and 7 are connected with a teatcup- arm 5 to a milkrack 2. This milkrack 2 is attached to the side of the milking parlour via hinges 3 and milkrack- arms 1 and a support 4. The milk flows from the teatcups 6 and 7 through a milkline 8 to a collector 9 and from there through a milkdrain 10 to a milktank which is not shown. During the attachment of the teatcups 6 and 7 around the teats the milkrack 2 is moved by a milkrobot with robotarms 12. The milkrobot is fastened to the side of the milking parlour with a support 11 or can be connected to a movable support that makes it possible that the milkrobot is moved to a different milking parlour for connecting teatcups of a different milkrack to a different cow. For that reason the milkrobot is detachable connected to the milkrack 2 with a robotgripper 13. For ensuring that the milkrack 2 remains in the same direction during attaching of the teatcups a guiderod 14 is attached along the robotarms 12. For following the position of a referenceteat the milkrobot is provided with sensors 16. When the milkrobot and the milkrack 2 are connected these sensors 16 when in a middle position are directed with a centre- line 1 at the teatcup 7, wherein the referenceteat will be brought. The sensors 16 are placed on a sensorsupport 15 which is connected to a slideguide 17, which can move in slide 18 in a direction P perpendicular to the longitudinal direction of the milking parlour. The position of the slide 18 relative to the slideguide 17 is recorded in the controlsystem. As the sensors 16 have a in the controlsystem known position relative to the milkrack 2, the milkrack can follow the movements of the udder of the animal to be milked, for instance by following the movements of the referenceteat. Through the now known position of the referenceteat the teatcup 7 can now be brought around the referenceteat by the milkrobot. With the teatposition sensor 19 the position of the other three teats relative to the referenceteat can be measured. In this way the positions of all teats are known in the controlsystem and the teatcups 6 can also be brought under their respective teats. In addition to measuring the relative teat- positions with the teatposition sensor 19 these can be determined also in other ways. It is for instance possible to calculate the relative positions of the teats from the known teatposition of a certain animal directly after milking and the time that has passed since the last milking. Due to the relative teatposition of a certain animal usually being not identical to the relative positions of the teatcups on the milkrack, the reference teat will not be directly above teatcup 7 when the teatcups 6 are brought under their respective teats and will no longer be in the centre of the detectionfield of the sensors 16 that are in the middle position. As the deviation is known in the controlsystem the sensors 16 will be moved in this known distance in direction P until the referenceteat is well detectable again. In figure 2 the sensorsystem is shown in topview. The sensors 16 are directionsensitive ultrasonic sensors with a centreline 1 of the ultrasonic beam, whereby each sensor 16 in the direction 1 can measure the distance to the object to be detected, in this case the referenceteat. Both sensors 16 together determine the detectionfield D wherein the presence and the position of the teat can be determined in the horizontal plane. In this case the detectionfield has been generated by the centrelines 1 of the detectionbeams making an angle α of approximately 80° so that it is more or less elliptical shaped. As this angle α; goes to 90° the shape will be more or less circular and with smaller angles a the ellipse will get narrower. By moving the sensorsupport 15 with the sensors 16 connected thereto in the direction P over a distance a in the one or the other direction the detectionfield moves to D' or D" . During this movement the slideguide is moved by a slidedrive 20 which slidedrive 20 is provided with means for determining the position of the slide relative to the milkrack 2. The slidedrive can be made in various known ways, for instance with a steppermotor, a servomotor or for instance with a single or multi-stage aircylinder whereby the slide can be brought in two or three positions relative to the slideguide. In the shown embodiment the angle oi is relative large and the distance between the detectionfield and the sensors 16 is small . In this way the to be detected teat gives a stronger reflection and for that reason its position can be determined accurately. This is made possible as the teat does not leave the detectionfield anymore as the changing position of the teat when bringing the teatcups 6 under a teat is followed by movement of the sensor in the direction P. Due to the more or less elliptical form of the detectionfield D the movements in the longitudinal direction of the animal have less influence. It is known that the dimension of the detectionfield D is no absolute boundary, but that in the centre of the ellipse the detectionfield D has the highest sensitivity, and that this sensitivity diminishes as an object is further from the centre. The ellipse D indicates the points whereby the sensitivity is more or less equal and outside of which the sensitivity comes under a value that is deemed acceptable. In figure 3 a sideview of figure 2 is shown, whereby the shown shape of the detectionfield D is as a field that is created with the ultrasonic sensor 16 with a transducent placed as shown in EP A 0323875 above a cone shaped mirror and whereby a substantially flat detectionfield is created. In the detectionfield D a to be detected teat S is shown. The invention can also be used in other sensor- systems for detecting the position of a teat and which have a limited detectionfield so as for instance position-determination systems which are based on the reflection of light. In addition to the herefore described use during attachment of teatcups around teats the movable detectionfield D of the sensors 16 is also used in another way. When the udder of the cow is approached from the front and the sensors 16 approach the teats, it is possible that there is no success in bringing the desired teat directly in the centre of the detectionfield D. It may happen for instance that the two frontteats of the udder are both irradiated by the sensors 16 and give reflections. It is then for the controlsystem of the sensorsystem not possible or very difficult to determine the position of the teats, as the received sensor information is contradictory. By moving the sensors 16 for instance in the direction P to the left and to irradiate the teat with the sensors 16 from the new position new reflections will be received, whereby it will then be possible that reflections of only one teat are received. After that the sensors 16 can be moved to the right whereby further additional information can be become available. By placing the sensors 16 on a sensorsupport 15 that is movable in the direction P the movements of the sensor 16 can be executed quickly as this sensorsupport 15 with sensors 16 has a far smaller mass that remaining part of the construction that moves to the udder. As a result of this quick movement the cow has often moved very little and the combination of the different viewpoints results in good position information. Due to this small mass the teats can be irradiated quickly with the sensors 16 on several positions breadthwise of the parlour, so that with the help of the detectionfield D the desired teat can be found and can be followed further during the attachment of the teatcups. It maybe possible to use this method of working also with sensors that are fixed to the positioning means. The movements of the sensors will then take more time, so that the accuracy is reduced. The construction though is more simple. In addition to an application as described with the above mentioned embodiment the invention can also be used in milksystems whereby not four but two teatcups are attached at a time, or whereby one teatcup at a time is attached to a teat. Also in that case the quick movement breadthwise of the detectionfield D is used for detecting quickly the desired frontteat. Thereby the sensor can move quickly breadthwise which saves time and the robot can remain moving slowly. This has the advantage that the robot under the animal to be milked makes quiet movements which reduces the irritation of the animal . In another embodiment the possibility to use two detectionfields is used for detecting the position of the hindteats as well. As the udder is irradiated from two different directions at least in one direction a hindteat will not be in the shadow of the frontteats. In this way with a single sensorsystem that can irradiate the udder from two positions the position of all four teats can be determined.

Claims: Claims 1. Device for milking animals comprising a milking device with teatcups (6,7), positioning means (11-13) for approaching the frontside of the udder with a teatcup, positioning a teatcup under a teat and attaching the teatcup around the teat, control means for controlling inter alia the milking device and the positioning means, a sensorsystem for detecting the position of a teat with at least one sensor (16) and a detectionfield (D) generated by the sensors which is substantially in a horizontal plane behind the sensors, whereby the sensors are coupled with the positioning means and whereby the sensorsystem feeds the control means with position information of the teats detected in the detectionfield, characterised in that the sensor- system comprises sensors (16) for generating a detectionfield (D) in at least two positions viewed breadthwise (P) . 2. Device according to claim 1, characterised in that the sensors (16) are movable breadthwise (P) relative to the positioning means. 3. Device in accordance with claim 2 , characterised in that the sensors (16) are connected to the positioning means (11-13) with a longitudinal guide (17) provided with a drive and with means (20) for determining the positions of the sensors relative to the positioning means . 4. Method for milking animals by moving teatcups (6,7) with positioning means (11-13) from the front to the udder of the animal to be milked, positioning them under a teat of the udder and attaching them to the teat whereafter milking is started, whereby during attaching the positioning means are controlled by a controlsystem and whereby the controlsystem is provided with information concerning the position of the teats by a sensorsystem coupled to the positioning means with a detectionfield (D) generated by at least one sensor (16) in a substantially horizontal plane behind the sensors and which can determine the position of at least one of the two frontteats, characterised in that the detection- field is generated in at least two positions viewed breadthwise (P) relative to the frontteats for determining the position of a frontteat. 5. Method for milking animals by moving teatcups (6,7) with positioning means (11-13) from the front to the udder of the animal to be milked, positioning them under a teat of the udder and attaching them to the teat whereafter milking is started, whereby during the attaching the positioning means are controlled by a controlsystem and whereby the controlsystem is provided with information concerning the position of the teats by a sensorsystem coupled to the positioning means with a detectionfield (D) generated by at least one sensor (16) in a substantially horizontal plane behind the sensors and which can determine the position of at least one of the two frontteats and whereby during attaching the teatcup has a fixed position relative to the positioning means, characterised in that during attaching the detectionfield (D) is moved breadthwise (P) relative to the positioning means so that one of the two frontteats remains in the more sensitive part of the detectionfield.

Inventors: OOSTERLING PIETER ADRIAAN, OOSTERLING, PIETER, ADRIAAN
Applicants: OOSTERLING PIETER ADRIAAN, PROLION BV, OOSTERLING, PIETER, ADRIAAN, PROLION B.V.
Application year: 1997
Main classification: A01J5
IPC codes: A01J5