HORIZONTAL SELF-LEVELING CONTROL SYSTEM FOR IMPLEMENTS OF TRACTOR VEHICLES AND SIMILAR VEHICLES.

Abstract

A horizontal self-leveling control system for implements of tractor vehicles and the like, tractor vehicles (1), harvesters or spraying equipment on which an implement (2) is installed, linked to a positioning system (3) equipped with control means for its lifting and tilting by means of a hydraulic circuit in which the different movements are carried out by means of hydraulic cylinders (4) whose actuation is in turn controlled by means of solenoid valves (5, 5',...), characterized in that it comprises: - At least one inertial sensor (8) integral with the implement, configured to measure the actual angular orientation of the implement under operating load conditions; - An electronic control unit (6); - Electrohydraulic actuation means connected to the hydraulic positioning system of the implement; Where the control unit (6) is configured to establish an operational reference plane defined by the instantaneous orientation of the implement under working conditions, continuously compare the measured orientation with said plane, determine lateral geometric deviations caused by variations in ground support or changes in the attitude of the carrier vehicle, and generate hydraulic corrections intended to compensate for said deviations, maintaining the functional geometry of the implement substantially constant and independent of the inclination or roll of the carrier vehicle, without requiring ground contact sensors.

Description

Horizontal self-leveling control system for implements of tractor vehicles and similar TECHNICAL SECTOR The invention falls within the agricultural machinery sector, specifically in electrohydraulic control systems intended for the positioning and stabilization of implements attached to tractor vehicles, as well as to harvester cutting platforms. More specifically, it refers to automatic control systems for the working geometry of agricultural implements during their operation on deformable, muddy or low load-bearing capacity terrain. The developed system allows the implement to transmit direct and autonomous commands to the tractor, optimizing its operation without constant operator intervention. More specifically, the system of the invention offers the following features: It maintains a constant horizontal level of the implement without continuous corrections from the operator. It prevents physical and mental exhaustion of the driver. It improves the quality of the final work, leaving the ground uniform for subsequent work (satellite or laser leveling). It reduces the time needed for this final preparation. The system described is compatible with vertical self-leveling control systems, and can work autonomously or in combination with this type of system. The system of the invention is applicable to any implement-tractor or harvester assembly that has a hydraulic system and electronic lift. BACKGROUND OF THE INVENTION In modern agricultural machinery, the use of hydraulic systems to control the lifting and tilting of implements attached to tractors or combine harvester cutting platforms is common. Current leveling solutions are based on: ground contact sensors, such as feeler wheels, skates or mechanical skis; systems that use the frame of the supporting vehicle as a geometric reference; automatic leveling systems integrated by machinery manufacturers; manual control assisted by level indicators. However, these solutions have significant limitations when working on low bearing capacity terrain, such as water-saturated, muddy soils, soils with lodged crops or with differential subsidence. Under these conditions: The sensors in contact with the ground sink, slide, or lose firm support, generating unrepresentative measurements; The sensing devices do not have a stable reference surface; The chassis of the supporting vehicle suffers tilting, swaying and twisting induced by the deformation of the terrain, ceasing to constitute a geometrically reliable reference plane; Conventional leveling systems do not distinguish between the actual slope of the terrain and the asymmetrical sinking of the vehicle; Manual control requires continuous corrections, is physically demanding, and its precision is limited to the working speed. As a result, the functional geometry of the implement cannot be maintained with operational precision using existing solutions, affecting the quality of work, uniformity of the terrain, or cutting height. Therefore, there is an unsolved technical problem in maintaining the stable functional geometry of an agricultural implement when the carrier vehicle does not constitute a reliable geometric reference and when the ground contact sensors are not usable. EXPLANATION OF THE INVENTION The proposed horizontal self-leveling control system for tractor implements fully and satisfactorily resolves the aforementioned problem, allowing the implement to maintain a constant position at a depth and tilt previously set by the operator. This stability is so consistent and precise that it would be impossible to achieve manually at the same working speed. The invention proposes an automatic geometric stabilization system for an agricultural implement attached to a tractor or harvester equipped with a hydraulic positioning system. The system comprises: At least one inertial orientation sensor structurally attached to the implement, configured to measure the actual angular attitude of the implement under operating load conditions; An electronic control unit; Electrohydraulic drive means connected to the implement positioning hydraulic system, such as a lateral implement correction cylinder. The control unit is configured to: 1. Establish an operational reference plane defined by the instantaneous orientation of the plane in a working condition selected by the operator; 2. Continuously compare the measured orientation of the implement with said reference plane; 3. Determine lateral geometric deviations caused by variations in ground support, differential subsidence, or changes in the attitude of the supporting vehicle; 4. Generate electro-hydraulic correction signals intended to act on the implement's hydraulic system to compensate for these deviations. The system operates without requiring physical contact sensors between the implement and the ground. The reference plane can be dynamically redefined during operation, allowing the operator to establish new geometric conditions under actual load. The system functionally overlays the original vehicle control, always maintaining priority over any manual operator intervention. Based on this structuring, the system of the invention achieves the functional geometric stabilization of the implement under conditions in which the carrying vehicle does not constitute a reliable spatial reference. In that sense, the system: It maintains the operational geometry of the implement regardless of the oscillations, inclinations or torsions of the vehicle; It allows operation on soils where mechanically referenced systems lose reliability; It eliminates dependence on the vehicle frame as a reference plane; It allows maintaining functional geometric tolerances not achievable through continuous manual control; It reduces the operator's workload while maintaining safety. In short, the overall technical effect is the automatic preservation of the implement's working geometry in low load-bearing capacity environments, through inertial reference located on the implement and electro-hydraulic corrective control decoupled from the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS To complement the description that follows and to aid in a better understanding of the characteristics of the invention, according to a preferred embodiment thereof, a set of drawings is included as an integral part of said description, in which, for illustrative and non-limiting purposes, the following has been represented: Figure 1 shows a perspective view of a tractor vehicle on which an implement is installed, an assembly in which the horizontal self-leveling system of the present invention is implemented. Figure 2 shows an electrical diagram of the system of the invention in its simplest variant. Figure 3 shows a view similar to that of Figure 2, corresponding to a more complex embodiment variant, specifically for larger machinery, such as harvesters. Figure 4 shows a view of the system of the invention applied to a combine harvester. Figure 5 shows, finally, a view of the system of the invention applied in a spraying system. PREFERRED EMBODIMENT OF THE INVENTION Figure 1 shows a tractor vehicle (1) on which an implement (2) is installed, linked to a positioning system (3) that controls both its elevation and inclination by means of a hydraulic circuit to adapt to the irregularities of the terrain, the different movements of said positioning system being by means of hydraulic cylinders (4) whose actuation is controlled in turn by means of solenoid valves (5, 5, ). Well, according to the invention, the system of the invention is constituted from an electronic control unit (6), whose outputs (7) are connected to the solenoid valves (5, 5, ) of the hydraulic system. The electronic control unit (6) is connected to a three-axis (X, Y, Z) inertial tilt sensor (8) located on the implement (2), of which only the X axis is used. This sensor will be installed on the implement itself, and not on the vehicle. For reading the sensor data and managing the output signals, proprietary software has been developed that allows for adjusting working times, intensities, and angles. The operator can modify the zero point level at any time, establishing a new control position within the range of -45° to +45°. This is possible via a switch (9) that activates and deactivates the electro-hydraulic functions controlled by the tractor's ECU. A push button (10) then allows the sensor's zero point to be reset to adapt to the terrain's topography, freezing the system outputs for greater accuracy when adjusting the working zero point. The system of the invention is applicable to both open and closed center hydraulic systems, so that, in the first case, an additional outlet is required for the operation of an auxiliary solenoid valve called the common (11) to perform the required movements. As previously stated, the system of the invention is equally applicable to longer platforms, such as harvesters, in which a variant of the software is used that incorporates adjustments to the operating parameters and allows compatibility with the different hydraulic configurations available on the market. In closed-center systems, a potentiometer (12) has been included to adjust the reaction speed of the hydraulic system, because proportional solenoid valves are commonly present in this type of hydraulic system.

Claims

1. Horizontal self-leveling control system for implements of tractor vehicles and the like, tractor vehicles (1), harvesters or spraying equipment on which an implement (2) is installed, linked to a positioning system (3) equipped with control means for its lifting and tilting by means of a hydraulic circuit in which the different movements are carried out by means of hydraulic cylinders (4) whose actuation is controlled in turn by means of solenoid valves (5, 5',...), characterized in that it comprises: - At least one inertial sensor (8) attached to the implement, configured to measure the actual angular orientation of the implement under operating load conditions; - An electronic control unit (6); - Electrohydraulic drive means connected to the hydraulic positioning system of the implement; Whereas the control unit (6) is configured to establish an operating reference plane defined by the instantaneous orientation of the implement under working conditions, continuously compare the measured orientation with said plane, determine lateral geometric deviations caused by variations in ground support or changes in the attitude of the carrier vehicle, and generate hydraulic corrections intended to compensate for said deviations, maintaining the functional geometry of the implement substantially constant and independent of the inclination or roll of the carrier vehicle, without requiring ground contact sensors. 2.A horizontal self-leveling control system for implements of tractors and similar vehicles, according to claim 1, characterized in that the control unit (6) includes a switch (9) that activates and deactivates the electro-hydraulic functions controlled by the vehicle's control unit, as well as a push button (10) for resetting the zero point of the gyroscopic sensor (8).

3. A horizontal self-leveling control system for implements of tractors and similar vehicles, according to claim 1, characterized in that the control unit (6) includes means for giving priority over any manual action by the operator.

4. A horizontal self-leveling control system for implements of tractors and similar vehicles, according to claim 1, characterized in that the electro-hydraulic means act on at least one lateral correction cylinder of the implement. 5.A horizontal self-leveling control system for implements of tractor vehicles and the like, according to claim 1, characterized in that when the hydraulic system of the tractor vehicle is open center, the control unit (6) includes an additional output for actuating an auxiliary solenoid valve or common (11).

6. A horizontal self-leveling control system for implements of tractor vehicles and the like, according to claim 1, characterized in that when the hydraulic system of the tractor vehicle is closed center, the control unit (6) includes a potentiometer (12) for adjusting the reaction speed of the hydraulic system.