DISTANCE MEASURING

Technical field

This document relates to an agricultural implement having a sensor device for contactless distance measurement. The document also relates to a method for contactless distance measurement.

Background

Methods and devices which measure the distance either between parts of an agricultural implement or between predefined positions on the agricultural implement and soil, and which require direct or indirect physical contact of both end positions of the measured distance, have clear drawbacks. The contact device itself affects the distance due to its tendency to sink into the ground, or else there is a risk of the contact device becoming deformed if a slowdown or obstacles are found in its way. Moreover, such a contact device becomes greatly worn down and needs to be replaced over time. One solution is to use a contactless sensor for distance measurement. One challenge with contactless sensors, however, is that they may require a definite placement in order for the measurement to be optimal and achieve the required distance to be measured, since they primarily measure distance in a predetermined direction. The required target pattern on the measurement object, such as a part of the agricultural implement, or soil beneath the agricultural implement, can in some cases only be achieved with a special placement of the sensor, and this is a placement which might be undesirable. One such solution is indicated in EP 1349442 where a sensor for measurement of an earth embankment is arranged in front of the tool making the earth embankment. A sensor with too exposed a placement risks becoming damaged by objects, such as dirt, clay, stones, plants, etc., which get in its way, or which are thrown up by the agricultural implement or the tractor to which it is coupled. Moreover, the measurement can be adversely affected by such objects.

It would thus be desirable to create an agricultural implement having a device for distance measurement which is robust and reliable in a harsh environment. Summary

One purpose of this document is to create a concept for distance measurement in an agricultural implement which is robust and reliable in a harsh environment. The invention is defined by the enclosed independent patent claims.

Embodiments will emerge from the dependent patent claims, the following specification, and the accompanying drawings.

According to a first aspect of the invention, an agricultural implement is provided for working the soil, comprising a first part and a sensor device. The sensor device contains a contactless sensor arranged on said first part and configured to measure a distance to at least one measurement object by means of radiation. Said measurement object is one of a second part of the agricultural implement and the soil before, during, or after the working of the soil. Said sensor device further comprises a reflector arranged between said sensor and the measurement object in the radiation’s measurement direction, so that said radiation changes its direction from the sensor to the measurement object by means of the reflector.

With the aid of such a sensor device, containing a reflector, the sensor can be placed in a more protected place where its radiation does not need to be oriented directly toward the measurement object. In this way, it is possible to avoid exposing the sensor to potential damage from loose objects which may be in motion around the measurement location, or having the measurement affected negatively by disturbance from such objects.

The contactless sensor can be, for example, a radar sensor, an ultrasound sensor, a lidar sensor, a laser sensor or the like. In one embodiment, "radiation from the sensor" means both the radiation coming directly from the sensor in the direction toward a measurement object and the radiation reflected on a measurement object in the direction back toward the sensor. The reflector can thus be adapted to reflect and change the direction of the radiation in the direction to and from the sensor.

The measurement with the aid of the contactless sensor can occur in a soil- working agricultural implement, a sowing machine, or another agricultural implement. The measurement can be between two parts of the agricultural implement, such as between two parts which are movable relative to each other, and it can be set up according to the desired application or situation, for example between a frame and a soil-working element such as a wheel or processing tool. Moreover, the measurement can be from a predetermined place on the agricultural implement to the soil underneath the agricultural implement.

Measurement relative to the ground can occur in various situations. For example, it is possible to measure a height in relation to the agricultural implement on an earth embankment produced by a levelling tool or an earth flow from another implement, the distance between a point on the agricultural implement and the soil when working soil located beneath the agricultural implement, the height at ground level for various points directly after working the soil, and so forth. Such a measurement can then be used to adjust a part or a soil-working tool on the agricultural implement and its position in relation to the ground in order to produce the desired result. In a further example, the sensor device can be placed on the agricultural implement in the form of a sowing machine downstream from a position on the sowing machine for application of granular material in the soil, for measurement of a distance to the applied granular material, for example in order to determine the applied depth thereof in the soil. Such a measurement can be used to adjust the feeding and/or application of the material in the soil.

In the example with a levelling tool which performs a subsequent working of the ground, the ground is levelled out, thereby forming an earth embankment, and when a sensor is used to measure the size of the earth embankment so as to adjust the position of the levelling tool when necessary, the sensor is especially subjected to a high risk of dirt, stones, or other objects damaging the sensor. With the present invention where a reflector is used to redirect the radiation from the contactless sensor along the path to the measurement object, in the present instance an earth embankment, the sensor can be placed in a more protected location. The sensor for example does not need to be placed totally exposed near the earth embankment, but instead it can be placed more encapsulated in a protected place. When the sensor is measuring the distance to the measurement object, the radiation can cross the reflector on its way to and from the measurement object. Thus, no clear view is required between the sensor and the measurement object. The same holds for other applications, such as with the sowing machine described above.

Moreover, the present invention can make it possible for a measurement to occur in a way which is otherwise difficult to achieve in situations where a certain part of the agricultural implement is blocking the clear view between the sensor and the measurement object. Instead of changing the placement of the sensor, which can be difficult or impossible, the reflector can be used to orient the measurement toward the measurement object.

The agricultural implement can be a soil-working agricultural implement.

In one embodiment, the contactless sensor can be a radar sensor and said radiation can be radar radiation. Radar radiation with a radar sensor can constitute an effective way of measuring a distance for an agricultural implement. It can also be robust to disturbances and is well suited for applications with a reflector. In one embodiment the reflector can be made of metal. Radar radiation can effectively bounce off a reflector made of metal.

In one embodiment, the reflector can have a concave surface against which the radiation can be reflected and changes direction. The concave shape of the reflector can thus be oriented such that the radiation from the sensor can reach it. The concave shape of the reflector, besides changing the direction of the radiation, can also change the dispersion of the radiation. Based on the concave configuration of the reflector, different target patterns can be created for the impinging of the radiation on the measurement object, such as a focal point, a focal line, or an elliptical or circular target pattern. Thus, a more exact and more practical measurement can be achieved. Moreover, an altered target pattern can make it possible to further adapt the placement of the sensor in order to protect the sensor when the target pattern would have otherwise been too wide for the measurement object. Instead of having to then place the sensor closer to the measurement object in order to avoid too widespread a target pattern, the sensor can be placed further away, more protected, while preserving the desired target pattern. The curvature of the concave reflector can be adapted to the distance being measured, the placement of the sensor and the reflector in relation to the measurement object, and/or the desired target pattern.

In one embodiment, the reflector can have a longitudinal extension in a direction away from the sensor, and the concave surface can have a concave shape along said longitudinal extension. The longitudinal extension can moreover extend along or in parallel with the measurement direction in which the sensor is oriented for the measurement. The concave surface can then provide an effective directing and/or focusing of the radiation along the measurement direction. In one embodiment, the sensor device can moreover comprise a protective cover which encloses the sensor and/or the reflector, and the protective cover can be made of a material which is substantially transparent to said radiation. For example, the protective cover can be made of plastic and the radiation can be radar radiation. The protective cover can then provide extra protection for the sensor and the reflector at the same time as the radiation reaches the measurement object for the measurement.

In one embodiment, the sensor device can moreover comprise a fastening element on which the sensor is arranged, the reflector and the fastening element being integrated in design. "Integrated in design" can mean that they are formed as a common piece. This can allow a simple and robust mounting of the sensor device on the agricultural implement. It also provides good protection for the sensor. The fastening element can have an opening through which the radiation from the sensor can be adapted to cross in the direction toward the reflector. The sensor can then be placed on a rear side of the fastening element in relation to the reflector. The sensor will then be placed even more protected.

In one embodiment, the reflector can have a longitudinal extension in a direction away from the sensor, and the reflector can comprise one or more wall elements extending along the reflector’s longitudinal extension. The longitudinal extension can furthermore extend along or parallel to the measurement direction in which the sensor is oriented for the measurement. The wall elements can then provide a protection for the reflector and the sensor from a sideways direction, not affecting the propagation of the radiation for the measurement. Given a concave surface on the reflector, the wall element can follow the curvature of the concave surface. The wall elements can extend in a direction perpendicular to the surface on the reflector against which the radiation is reflected and changes direction.

In one embodiment, the agricultural implement can furthermore comprise an adjustment device to adjust the placement of said first part, said second part, and/or another part of the agricultural implement based on measurement of the distance from the measurement object with said sensor device. For example, the adjustment can be done for the second part of the agricultural implement in relation to the first part, in relation to another part of the agricultural implement, or in relation to the soil beneath the agricultural implement. Moreover, the adjustment can be done for the second part or another part of the agricultural implement in relation to the soil before, during, or after the working of the soil, when the agricultural implement is adapted for working of the soil.

According to another aspect of the invention, a method is indicated, involving the steps of arranging a sensor device containing a contactless sensor and a reflector on a first part of an agricultural implement and measuring a distance to a measurement object by means of radiation from said sensor, wherein said measurement object is one of a second part of the agricultural implement and the soil before, during, or after the working of the soil, and wherein the radiation during said measurement is reflected and changes direction by means of said reflector arranged between the sensor and the measurement object in the radiation’s measurement direction. In the same way as described above for the embodiments of the agricultural implement, the described method can provide a measurement technique which is reliable and robust in a harsh environment where the measurement occurs in a more protected placement of the sensor. The sensor device can be a sensor device as described in one of the above embodiments.

In one embodiment, the measurement object can be a second part of the agricultural implement and the method can further involve the step of adjusting said second part in relation to said first part, or another part of the agricultural implement, based on the measurement of the distance to said second part.

In one embodiment, the measurement object can be soil beneath the agricultural implement before, during, or after the working of the soil, and the method can involve the step of adjusting a part of the agricultural implement in relation to the soil based on the measurement of the distance to the soil.

Brief description of the drawings

Fig. 1 shows a side view of one part of an agricultural implement according to the prior art.

Fig. 2 shows a schematic side view of one part of an agricultural implement according to one embodiment of the present invention.

Fig. 3 shows a side view of one part of an agricultural implement according to one embodiment of the present invention. Fig. 4 shows a perspective view of an agricultural implement according to one embodiment of the present invention.

Fig. 5 shows a side view of an agricultural implement according to one embodiment of the present invention.

Fig. 6 shows a side view of an agricultural implement according to one embodiment of the present invention.

Fig. 7 shows a perspective view of a sensor device according to one embodiment of the present invention.

Fig. 8 shows a flow chart of a method according to one embodiment of the present invention.

Detailed description

Fig. 1 illustrates a portion of an agricultural implement 100 according to the prior art, where a distance to a measurement object 140 is measured by means of radiation from a contactless sensor 110. In order to get a correct measurement, it is necessary to place the sensor 110 so as to make a right angle with the measurement object 140. In the illustrated instance, the distance is measured to an earth embankment which is built up in front of the agricultural implement 100 with the aid of a levelling tool 103. The sensor 110 must then be placed in a position which can then be exposed, for example, to dirt, stones, gravel, plants, and the like, which can ruin the sensor 110 or disturb the measurement.

Fig. 2 illustrates schematically the principle of the present invention. A sensor device 2 is arranged to measure the distance to a measurement object 40. The sensor device 2 comprises a contactless sensor 10. The sensor 10 is placed on a first part 30 of an agricultural implement 1. The sensor 10 is arranged to measure a distance to the measurement object 40 by means of radiation 12. The sensor device 2 further comprises a reflector 20. The radiation 12 along the measurement direction from the sensor 10 to the measurement object is reflected on the reflector 20 so that the radiation changes direction. The radiation 12 can be, for example, radar radiation, ultrasound radiation, lidar radiation or laser radiation. Thanks to such a configuration of the arrangement on the agricultural implement 1, the sensor 10 can be placed more protected, since it does not need to be oriented with a particular angle relative to the measurement object 40. Instead, the reflector 20 is designed and placed such that it is not equally vulnerable to disturbing objects, and adapted so that the radiation 12 impinges on the measurement object 40 in the desired manner. In the embodiment illustrated in Fig. 2, the reflector 20 has a straight surface 22 against which the radiation 12 is reflected and changes direction.

Fig. 3 illustrates an embodiment where a sensor device 2 is placed on a first part 31 of the agricultural implement 1. The sensor 10 measures the distance to a measurement object 41 by means of radiation. In the illustrated example, the measurement object 41 is composed of an earth embankment which is built up by a levelling tool 3 coupled to the first part 31 of the agricultural implement 1. The first part 31 can be adjusted in relation to the ground in order to affect how an earth embankment is built up. This adjustment can be based on the distance measurement with the sensor device 2. In the same way, the distance measurement can occur in relation to other ground on which the agricultural implement 1 and the sensor device 2 are moving. This can occur before, during, and/or after the working of the soil which the agricultural implement 1 is adapted to perform.

The reflector 21 reflects the radiation 12 so as to change its direction toward the measurement object 41. The reflector 21 has a concave surface 23 against which the radiation 12 is reflected and changes direction. The concave surface 23 means that the radiation 12 from the sensor 10 is focused on a smaller surface at the measurement object 41 so that a desired target pattern is created. The curvature of the concave surface 23 at the reflector 21 can be adapted to create a desired target pattern on the measurement object 41.

The agricultural implement 1 further comprises an adjustment device 50 adapted to enable an adjustment of the first part 31 in relation to the ground. In this way, the level at the earth embankment formed by the harrow board 3 can be adjusted, based on the measurement of the distance measured by the sensor device 2. Since the measurement object 41 is composed of a portion of the ground being the earth embankment so formed, the size of the earth embankment can be measured and if necessary adjusted with the aid of the adjustment device.

Fig. 4-6 illustrate an embodiment of the invention where the sensor device 2 is arranged on a first part 32 of the agricultural implement 1 and adapted to measure the distance to a measurement object 42, consisting of a second part of the agricultural implement 1. In this embodiment, the sensor 10 can be placed in the same way in a more protected manner and the radiation 12 can be oriented optimally to the measurement object 42 by means of the reflector 21. The illustrated reflector 21 has a concave surface 23 which at the same time as it orients the radiation 12 to the measurement object 42 can also focus the radiation 12 to a desired target pattern. In this way, it is possible to create, with the aid of the reflector 21, a target pattern which prevents the radiation 12 from striking unwanted parts of the agricultural implement 1, for example.

A distance measurement from the sensor 10 to a second part 42 of the agricultural implement can be used to adjust, for example, the second part in relation to the first part 32. This can be done with the aid of the adjustment device 51 coupled at one end to the second part 42 of the agricultural implement 1. The other end of the adjustment device 51 can be coupled to the first part 32 of the agricultural implement 1 or another part of the agricultural implement 1.

In the illustrated example, the agricultural implement 1 is moving over ground 4, which can be seen in Fig. 5-6, and the second part 42 consists of a wheel axle, the placement of which in relation to the first part 32 of the agricultural implement 1 can be adjusted. The agricultural implement 1 further contains a processing tool 5 to work the soil 4. An adjustment of the second part 42 thus changes the working depth in the soil 4 for the processing tool 5. The processing tool 5 can be fixed in height to the first part 32 of the agricultural implement 1.

Fig. 7 illustrates a sensor device 2 comprising a sensor 10 and a reflector 21 for measuring a distance to a measurement object 40, 41, 42 as described above by means of radiation 12. The reflector 21 has a concave surface 23 adapted to reflect radiation 12 from the sensor 10 to the measurement object 40, 41, 42. For an effective and protected mounting and placement of the sensor device 2, the sensor device 2 comprises a fastening element 24 for fastening the sensor 10. The fastening element is integrated with the reflector 20. The fastening element 24 may have an opening 25 so that the sensor 10 can be mounted on a rear side of the fastening element 24, which is facing away from the reflector 21. Such a mounting of the sensor 10 on a fastening element 24 can provide further protection for the sensor 10. Radiation 12 from the sensor 10 is then oriented through the opening 25 onto the reflector 21. The sensor device 2 further comprises a fastening device 26 for fastening the sensor device 2 to a first part 30, 31, 32 of the agricultural implement 1. The fastening device 26 can have various configurations, depending on the application and how the sensor device 2 is designed to be mounted on the agricultural implement 1.

In the illustrated embodiment, the reflector 21 comprises two wall elements 27 which extend along the concave surface 23 in a longitudinal direction of the reflector 21. The wall elements 27 can provide stability to the reflector 21 and additional protection for the sensor 10 and the reflector surface 23. The wall elements 27 extend along respective longitudinal edges of the reflector 21. The wall elements 27 can also extend along edges of the fastening element 24.

In one embodiment, the sensor 10, the fastening element 25 and the reflector can together be adjustable in relation to the fastening device 26. In this way, the sensor device 2 can be mounted on a first part 30, 31, 32 of the agricultural implement 1, and a more precise adjustment of the sensor device 2 for distance measurement can then be done in relation to the fastening device 26.

What has been described above for a sensor device 2 in the embodiment of Fig. 7 with a concave surface 23 on the reflector 21 will be applied in the same way to a sensor device 2 having a reflector 20 with a straight surface 22. For example, it will have a fastening element 24 with opening 25, a fastening device 26, and wall elements 27.

Fig. 8 illustrates a method 200 for measuring a distance to a measurement object 40, 41, 42 involving the steps of arranging 202 a sensor device comprising a sensor 10 and a reflector 20, 21 on a first part 30, 31, 32 of an agricultural implement 1, and measuring 204 a distance with said sensor 10 to said measurement object 40, 41, 42. The measurement 204 is done with radiation 12 from the sensor 10. The measurement object 40, 41, 42 is one of a second part 42 of the agricultural implement 1 and the soil 41 before, during, or after the working of the soil, when the agricultural implement 1 is used for working of the soil. The radiation 12 during the measurement 204 is reflected and changes direction by means of the reflector 20, 21 arranged between the sensor and the measurement object in the radiation’s measurement direction. The sensor device 2 used in the method 200 can be configured according to any embodiment as described above.