Flexible Skid Sensor for Combine Header Height Control
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Solution Overview
Problem
Existing header height control systems in agricultural combine harvesters face issues with incorrect measurements and potential damage due to lateral forces exerted on sensor assemblies during turns, particularly when navigating uneven terrain.
Innovation Solution
A sensor assembly with pivotable skids connected through a flexible arrangement featuring a support bracket and an elastic element, such as a coil spring, which allows lateral deflection and returns to its original position when forces exceed a threshold, preventing damage and maintaining accurate ground level measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rigid connections are used between skids and pivot pin, then measurement precision is improved, but reliability deteriorates due to damage risk under lateral forces
Solution Approach 1:
The connection between skid and pivot pin changes from rigid to flexible by introducing an elastic element (coil spring). This parameter change allows the connection to be rigid enough for accurate measurement transmission while flexible enough to withstand lateral forces during turns, resolving the contradiction between measurement precision and reliability
Solution Approach 2:
The elastic element acts as a cushioning mechanism that absorbs lateral forces before they can damage the sensor assembly. By providing this protective element in advance, the system maintains both measurement accuracy and durability under varying operating conditions
2Reliability
If flexible connections are used to protect against lateral forces, then reliability is improved, but measurement precision deteriorates due to potential interference with angular displacement
Solution Approach 1:
The elastic element is designed with specific local qualities: it is constrained to bend only in the longitudinal plane (parallel to pivot pin) while being rigid in the lateral direction (perpendicular to pivot pin). This localized flexibility allows the connection to be protective without interfering with measurement accuracy
Solution Approach 2:
The connection transitions from a static rigid structure to a dynamic flexible connection that adapts its stiffness based on operating conditions. During normal operation, the elastic element remains linear and maintains measurement precision; during lateral forces, it bends to provide protection
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The flexible connection reduces the risk of damage to sensor assemblies during turns and ensures accurate header height adjustments by allowing lateral deflection without interfering with ground level displacement measurements.
Implementation Method 1
The elastic element is configured to bend when lateral forces acting on the skid exceed a given threshold. The elastic element returns to a linear shape when the lateral forces drop below the threshold, thereby returning the skid to its non-deflected position.
Implementation Method 2
a pivotable skids or plates which are dragged along the ground surface, and sensors configured to measure the rotation of the skids or plates about an axis oriented in the longitudinal direction of the header
Data Source
Figure 1
Figure 2~3
Figure 4a~4b
AI summary
A sensor assembly for an agricultural header according to the invention comprises a pivot pin (13) and one or more skids (10) attached thereto and configured to translate changes in the ground level into a rotation of the pivot pin, and a sensor (16) for measuring the rotation of the pin. At least one skid is attached to the pivot pin (13) through a flexible connection comprising a support bracket (19) and an elastic element (35) mounted between the pivot pin (13) and the end of the skid (10). The skid is pivotably connected to the support bracket (19) so as to be able to deflect laterally, and the elastic element (35) is configured to bend when lateral forces acting in the skid exceed a given threshold. The elastic element (35) returns to a linear shape when the lateral forces drop below the threshold, thereby returning the skid (10) to its non-deflected state. Bending of the elastic element (35) in a direction perpendicular to the pivot pin is obstructed so that the elastic element does not interfere with the angular displacement of the skid (10) caused by variations in the ground level.