Paving Machine Screed Extension Control for Surface Consistency

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Solution Overview

Problem

Paving machines often produce inconsistencies in the road mat due to differences in elevation between the main screed and screed extensions, leading to undesirable surface conditions like transition marks and texture differences.

Innovation Solution

A system and method using sensors and a controller to identify and characterize undesirable surface conditions, adjusting the height and angle of attack of screed extensions to maintain consistency with the main screed, ensuring the screed extensions remain within a predetermined threshold to prevent such issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the tow arms are adjusted to change the vertical height, then the paving machine can adapt to different base conditions, but the trailing edge of the main screed and screed extensions are disposed at different elevations causing inconsistencies in the paved mat

Engineering Contradiction:

Improveadaptability to different base conditionsVSAvoidelevation consistency of screed trailing edges

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The screed extension angle of attack actuator enables dynamic adjustment of the screed extension's angle of attack independently from the main screed. This allows the system to adapt to changing base conditions while maintaining elevation consistency between the main screed and screed extensions by continuously adjusting the extension's angle to compensate for tow arm position changes.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The angle of attack sensor provides real-time feedback on the screed extension's angle of attack to the controller. The controller uses this feedback to adjust the angle of attack actuator, ensuring the screed extension maintains the correct angle relative to the base and remains aligned with the main screed's trailing edge elevation.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If manual adjustments are used to maintain screed extension alignment, then elevation consistency can be maintained, but operator intervention is required increasing labor and reducing productivity

Engineering Contradiction:

Improvealignment consistency of screed extensionVSAvoidcontinuous paving operation capability

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The automated control system performs self-adjustment of the screed extension's angle of attack based on sensor feedback. The controller continuously monitors the angle of attack sensor data and automatically actuates the angle of attack actuator to maintain proper alignment, eliminating the need for manual operator intervention and enabling continuous productive operation.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The manual mechanical adjustment process is replaced with an automated electromechanical control system. The angle of attack sensor and controller work together with the angle of attack actuator to automatically maintain screed extension alignment, substituting manual mechanical operations with an automated closed-loop control system that maintains precision without operator intervention.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the screed extension angle of attack is not adjusted, then the structure remains simple, but undesirable surface conditions like transition marks and texture differences occur

Engineering Contradiction:

Improvescreed extension control mechanismVSAvoidsurface uniformity of paved mat

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The screed assembly is segmented into independently controllable components: the main screed and the screed extension with separate angle of attack adjustment mechanisms. This segmentation allows the extension's angle of attack to be adjusted independently to optimize surface uniformity at the extension interface without complicating the overall structure, as each segment has its own dedicated control actuator and sensor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The angle of attack parameter of the screed extension is dynamically changed based on real-time sensor feedback. By adjusting this geometric parameter through the angle of attack actuator, the system prevents formation of transition marks and texture differences, improving surface uniformity through controlled parameter variation rather than complex structural changes.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11746480B2System, apparatus, and method for controlling screed extender of paving machine

Publication Date: 2023.09.05 CATERPILLAR PAVING PROD INC

AI summary

A system, apparatus, and method can control one or more screed extensions or extenders of a paving machine. Such control can include identifying a location of an undesirable surface condition of a mat paved on a base by the paving machine using data from one or more sensors associated with a screed extension; characterizing the undesirable surface condition of the mat; and adjusting a height and/or an angle of attack of an extension plate of the screed extension to prevent future occurrences of the undesirable surface condition responsive to the identification and characterization of the undesirable surface condition. The location of the undesirable surface condition can represent a start of the undesirable surface condition in a transverse direction of the paving machine and can be associated with either an interface between the screed extension and a main screed or outward of the interface, along a length of the extension plate of the screed extension.