WO2001003503A1

WO2001003503A1 - Device for automatically controlling a spray boom inclination level

Info

Publication number: WO2001003503A1
Application number: PCT/FR2000/001460
Authority: WO
Inventors: Michel Barrau
Original assignee: Michel Barrau
Priority date: 1999-07-09
Filing date: 2000-05-29
Publication date: 2001-01-18
Also published as: FR2795913A1

Abstract

The invention concerns a device for automatically controlling the inclination level of a tractor pendular spray boom (10), comprising means for displacing its centre of gravity to modify its inclination. The invention is characterised in that it comprises means for detecting (2, 2') an angular displacement of the spray boom (10) relative to the tractor body (3) beyond a predetermined threshold, and means for acting (S) on the means modifying the inclination, activated as long as an angular displacement greater than a predetermined threshold is detected.

Description

"Device for automatic control of the tilt level of a spray boom"

The invention is in the field of electronic devices finding their place within the spraying equipment with which agricultural vehicles intended for processing crops are equipped.

The invention allows the farmer to carry out spraying operations on any terrain, in particular inclined, in complete safety and efficiency.

Current sprayers use a boom suspended pendularly at a point by a central shock absorber: the boom floats, it is not rigid with respect to the chassis. It is positioned naturally so that the center of gravity of the ramp is arranged vertically below the point of suspension.

This is why it was necessary to find a solution to allow the ramp to be always parallel to the surface of the soil to be treated, in particular when this ground is sloping, while keeping its suspension in order to obtain a perfect job. crop processing.

The means used in a manner known to those skilled in the art to tilt the sprayer boom is to place it on a slide, itself suspended from the anchor point on the tractor. A jack allows lateral movement of the ramp on this slide, and the center of gravity of the slide and ramp assembly is therefore displaced, which causes the inclination of the assembly.

This device is known per se and very widely used. However, it does not allow continuous correction of the inclination of the ramp according to the evolution of the slope of the terrain.

Certain automatic correction devices have been proposed. Such devices are based on the use of an ultrasonic sensor system: such a sensor is fixed at the end of the ramp, it controls the distance between the ends of the ramp and the ground, then causes a correction of the inclination of the ramp thanks to a hydraulic cylinder.

The main drawback of this system is that it does not work when the crops are already high.

The ramp does not follow the ground, so there is a problem of efficiency of spraying and the frequent risk that one end of the boom touches the ground, it is then necessary to touch up the compensation cylinder to restore the level of the boom.

Among the prior art documents describing spray boom tilt control devices, the following documents may be cited:

French patent n ° FR2779031, entitled "Pendulum boom assembly for agricultural spraying machine, equipped with a tilt correction device", filed on 02/06/98 by the company EXEL INDUSTRIES This document describes a control system semi-automatic, that is to say that the user of the machine must enter an inclination setpoint (by a setpoint button), and that means make it possible to control the inclination of the ramp to the setpoints given by the control panel C. The tilt correction device comprises a system of rods in the shape of a polygon, which is acted upon to make the ramp move.

This system therefore requires the installation of links and sophisticated mechanics, which are not necessarily adaptable to any type of tractor and sprayer.

French patent n ° FR2777746, "Suspension device for sprayer booms", filed on 22/04/98 by KUHN NODET SA

In this document, a suspension device is described capable of rapidly damping the various oscillations to which the spray bars are subjected. It also makes it possible to adjust the slope of the ramp, by means of adjustment members capable of acting on the mounting elements (connecting rods, rockers, blocking members), so as to modify the spacing between the center of gravity and the instantaneous center of rotation of the ramp.

This system is not automated. It is simply specified that "the behavior of the boom can advantageously be controlled by a computer having previously memorized the characteristics of the terrain on which the sprayer is moving."

French patents No. FR2734498 and FR2734499, entitled "Method for controlling the lifting of a spray boom" and "Method for adjusting the position of a spray boom", filed on 05/24/95 by a company AGROTRONICS SA

These various documents describe or cite spraying installations equipped with an adjustment device which comprises means:

- measuring the height of the boom arm relative to a support, such as the ground, and

- comparison of the heights measured with at least one set value,

- detecting a difference between each height measured and the set value, - developing an at least indirect control signal from each motor member of the appropriate ramp with a view to correcting the difference found. The first of the cited Agrotronics prior art patents relates to a spray monitoring means which, when it detects a spray fault, causes the boom to be raised (by changing the set values) and when it detects the setting depending on the spray, restores the working instructions.

This device does not seem to be working satisfactorily, and in any event does not allow the ramp to be tilted according to the slope of the terrain on which the tractor is moving. The second patent allows the ramp to be adjusted relative to a surface S substantially parallel to the carrier surface 2, but always by means of reference values previously defined by the user according to his observation of the slope of the field.

This document discloses a device in which the slope correction of the spraying boom is effected by a correction carried out in a fractional manner by proceeding by iterations, instead of carrying it out in a single operation.

According to the description in this document, you must measure the height of each of the arms of the ramp relative to a support, such as the ground, then make comparisons of the half-sum of the measured heights and the half-difference of the measured heights each with a set value.

This device uses ultrasonic sensors to measure the heights of the ramps relative to the ground. In the case of tall crops, the accuracy of the measurements made by this device is naturally affected, and the operation of the device is uncertain.

Other patent documents are known which disclose devices for adjusting the inclination of a spray boom, using for their operation measurements of the height of the boom relative to the ground (in particular the patent documents EP157592 and FR2603453). Each of these documents describes a device suitable for reproducing with the sprayer boom a setpoint set beforehand by the user, most often from the driver's cabin of the tractor, in view of the estimated slope of the field.

It is clear that these devices are not adapted to accommodate rapid changes in the slope of the field, or to react to the effects of tilting of the spray boom during tractor turning operations, which conventionally pose problems of friction on the ground of the end of the ramp.

The object of the present invention is to optimize the spraying treatment operations by ensuring maximum efficiency for the farmer by ensuring both total stability of the sprayer boom and a permanently parallel position. on the ground at a height where the treatment is most effective, regardless of the height of the vegetation or crops treated.

The device according to the invention is moreover adaptable mainly to any type of spray boom of the pendulum type.

It is simple to implement and economical to carry out.

The invention proposed for this purpose an automatic device for controlling the level of inclination of a pendulum type sprayer boom for a tractor, of the type comprising means for moving its center of gravity to modify its inclination, characterized in that 'It comprises means for detecting an angular displacement of the sprayer boom relative to the chassis of the tractor beyond a predetermined threshold, and means for acting on the means for modifying the inclination, actuated as long as an angular displacement greater than a predetermined threshold is detected.

It is understood that by this arrangement, the device according to the invention uses a measurement of angular position relative to the chassis of the tractor and not relative to the height of the arms of the ramp at its ends above the ground or crops, which is both much simpler and significantly more effective.

Furthermore, the choice of an inclination correction device as long as the sensors have not returned to the initial position allows the implementation of a servo loop which is both simple and inexpensive, and whose reaction speed simply depends on the reactivity parameters of the hydraulic cylinder for lateral movement of the ramp, and on the mechanical parameters of said ramp.

Finally, it is clear that this device is then very easily adaptable to most of the pendulum spray booms, by simple addition of a sensor and an electronic control unit.

The description and the drawings of a preferred embodiment of the invention, given below, will make it possible to better understand the aims and advantages of the invention. It is clear that this description is given by way of example, and is not limiting. In the drawings: - Figure 1 schematically illustrates a tractor with a pendular spray boom;

- Figure 2 shows a block diagram of the automatic slope adjustment device according to the invention.

Figure 1 shows schematically the conventional arrangement of a pendulum type spray boom 10, mainly suspended at a point 11 of a frame 3 secured to a tractor 12, so as to permanently take a determined position of equilibrium by placing the center of gravity of the ramp under the suspension point 11. A hydraulic cylinder 5, arranged on a slide suspended at point 11, allows the lateral movement of the ramp 10 relative to its suspension point 11. As we as said, this type of device is known to those skilled in the art, and does not constitute the subject of the present invention.

In the present case, a pendulum type ramp is used, provided with a means for modifying the angular position of the ramp. The lateral displacement cylinder is simply the currently most widely used means in practice.

The device according to the invention then consists of an electronic unit 1 and two sensors 2, 2 'fixed to the chassis 3 mounted on the tractor 12. These sensors 2, 2' are arranged on either side of the point suspension 11 of the spray boom, facing a predetermined part of the boom (for example a horizontal bar of the boom).

It can be an optical sensor (cell and LED) or, in the case described here without limitation, a simple electric brushed contactor which establishes a contact only when the sensor is located opposite a conductive area (here the horizontal bar).

It is understood that this type of sensor makes it possible to create a contact area of predetermined width, so that in fact an acceptable tilt threshold is determined, beyond which the sensor changes state and causes the action on the cylinder 5.

The electronic unit 1, which is favorably fixed to the chassis 3, comprises an electronic assembly including an electronic card equipped:

- A voltage regulation supply circuit to have a precise 5 Volt supply, connected to the tractor's electrical network. - A conventional microcontroller.

- Various control circuits, relays, logic circuits and power circuits, adapted to control the hydraulic cylinder 5 in motion.

- An RS 232 plug so that it can be reprogrammed at any time with a laptop on the work site. The description of the electronic unit and the drawing (Figure 2) relate to a preferred embodiment and operation of the invention; this description is given by way of example and is not limiting.

It describes the articulation between the various elements of the device organized around the box 1 comprising in particular the “intelligent” electronic card, the position sensors 2, electrical outputs 3 going to actuate the jack 5 or hydraulic solenoid valve, a remote control 6 fixed in the tractor cabin 4, twelve volts power supply 5 and laptop 8.

As can be seen in FIG. 2, the information emanating from the position sensors 2, 2 ′ is entered into the electronic unit 6 and transmitted to the microcontroller. The microcontroller is also interface with the control 6, placed in the tractor cabin 12. This control 6 includes a button 7 allowing to pass from an automatic control by the microcontroller to a manual control, and actuation buttons of the jack 5 in one direction or the other, as well as indicator lights for movement of the ramp (for example an indicator for each direction of inclination of the ramp), a stable position indicator (for example a central green indicator).

The microcontroller has the role of managing the inputs and outputs of the information and directing the correction operations (sensor 2, 2 'to the hydraulic cylinder 5 or equivalent solenoid valve). It is programmed to provide an RS 232 serial link.

It is understood that the use of a microcontroller makes it possible to preset parameters such as speed of catching up of slope by the hydraulic jack 5, or time delay before actuating the jack, for example so as not to take into account all the small vibrations of the tractor linked to local variations in ground level.

During use, if the sprayer boom 4, following a start of inclination of the agricultural tractor 12 and sprayer boom 4 due to work on a slope, comes to activate one of the two sensors 2, 2 ', information is transmitted to the electronic unit 1 which corrects the compensation cylinder 5 in order to reposition the ramp 4 parallel to the ground. When neither of the two sensors 2, 2 'is actuated, this means that the ramp 4 remains parallel to the chassis of the tractor, that is to say substantially parallel to the ground.

In the example described here, two sensors are used, for redundancy, but it is clear that a single angular displacement sensor could be used.

It is indeed a functional diagram of the device for self-checking the level of inclination of a sprayer boom.

The automatic tilt control process also makes it possible to manage and activate a sprayer boom fitted with a hydraulic compensation cylinder.

In a certain number of cases, the spraying boom is in fact made up of two separately articulated arms arranged around a generally horizontal central segment, so that they can be arranged in a "V" shape.

This arrangement is particularly useful in the case of fields of non-constant slope, for example in the case of downward slope in superelevation, which is followed by a flat or an ascending slope. It is understood that in this case, the parallelism of the ramp with the ground is no longer ensured over the entire length of the ramp. A manual correction of the angle of the "V" by the tractor driver is carried out, but it must then be taken into account by the automatic slope control according to the invention.

In this variant, the modification of the angle of the 'V of the two arms of the ramp is also automated, which then involves adding height sensors of each arm relative to the vegetation, and no longer relative to the chassis of the tractor, previously considered to be representative of the local slope of the agricultural soil.

For example, a carbon brush is used which is placed completely at the end of each arm, in which an electric current is passed. During a contact of the broom with the vegetation if the arm of the corresponding ramp is too low, the current flows through the vegetation to ground, and a variation in current is then detected. This variation is used to modify the angular position of the arm.

In this case, the position sensors of each arm relative to the ground determine the action of the means for modifying the inclination of each arm (determination of the angle of the "V"), and a central means for positioning the ramp. places the center of gravity so as to obtain a correct overall inclination of the 'V with respect to the slope of the terrain. This second means is similar in nature to the device of the present invention.

According to a favorable implementation, the angular position control begins with a correction of the slope by the central means, then with a correction of the positions of the ends of the ramp above the vegetation. An iteration of the process is naturally carried out, so as to closely follow the evolution of the soil.

The scope of the present invention is not limited to the details and embodiments specified above, which must be considered by way of example, but on the contrary extends to modifications within the scope of the professional.

Claims

1. Device for automatically controlling the inclination level of a pendulum type spray boom (4) suspended at one point (11) from a chassis (3) secured to a tractor (12), the boom (4) being of the type comprising a means of displacement (5) of its center of gravity to modify its inclination, characterized in that it comprises means of detection (2, 2 ′) of an angular displacement of the spraying boom (4) relative to the chassis (3) of the tractor beyond a predetermined threshold, and means of action (1) on the means (5) of inclination modification, actuated as long as an angular displacement greater than a predetermined threshold is detected.

2. Device according to claim 1, characterized in that the detection means (2, 2 ') of an angular displacement of the spraying boom (4) relative to the chassis of the tractor beyond a predetermined threshold comprise two sensors (2) fixed to the chassis (3) of the tractor with regard to the spraying boom (4) on either side of its suspension point (11), suitable for causing an electrical signal modification when the angular position of the ramp leaves a predetermined range with respect to the chassis.

3. Device according to claim 2, characterized in that the sensors are electric brushed contactors.

4. Device according to any one of claims 1 to 3, characterized in that the action means (1) on the inclination modification means comprise a housing / electronic card (1) comprising a microcontroller adapted to control the operation of the means of displacement of the center of gravity of the ramp according to information emanating from the detection means (2, 2 "),

5. Device according to any one of claims 1 to 4, characterized in that it comprises a means for disengaging the microcontroller, and for manual control of the inclination of the ramp (4).

6. Device according to any one of claims 1 to 5, characterized in that it comprises, in the case of a spray boom in two arms articulated separately and inclined by two means for modifying inclination, control means (1) separated from the two arms of the ramp (4), according to information emanating from displacement detection means (2, 2 ′) and from means for detecting the height of each arm above the vegetation.

7. Device according to claim 6, characterized in that the height detection means of each arm above the vegetation each comprise a carbon brush disposed completely at the end of each arm, and means for passing an electric current in this brush, and means for detecting an electrical signal variation in the brush.