Asphalt Milling Machine Elevation Control via GNSS Floating Plate
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Solution Overview
Problem
Current asphalt milling machine controls face challenges in accurately controlling the depth and elevation of milled surfaces, especially in complex scenarios where obstructions and transitions require precise adjustments, often leading to suboptimal repaving results.
Innovation Solution
An asphalt milling machine control system utilizing a GNSS receiver, a floating plate with a vertically movable sensor, and a processor to determine the desired elevation and generate correction values for the milling drum, ensuring precise milling to a design elevation by combining three-dimensional surface maps and real-time sensor data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional side plate controls are used to sense string line adjacent the milling path, then the control system is simple and easy to operate, but the measurement precision of surface elevation is insufficient for complex scenarios with obstructions
Solution Approach 1:
The patent replaces traditional mechanical side plate controls with a GNSS receiver-based positioning system. The GNSS receiver determines the precise location of the floating plate, and a processor calculates elevation data by comparing actual position with design surface information, eliminating the need for mechanical string line sensing while achieving higher measurement precision.
Solution Approach 2:
The patent introduces a floating plate as an intermediary element that slides over the unmilled surface adjacent to the milling area. This floating plate serves as a reference point for the GNSS receiver to measure surface elevation indirectly, allowing accurate measurement even when direct access to the milling area is blocked by obstructions.
2Measurement precision
If total station with total station target is used to monitor machine movement and control grade, then measurement precision is improved, but the line of sight can be blocked by traffic or obstructions
Solution Approach 1:
The patent replaces the total station optical measurement system with a GNSS satellite-based positioning system. The GNSS receiver continuously tracks satellite signals to determine the floating plate's position and elevation without requiring line of sight, eliminating obstruction problems while maintaining high measurement precision.
Solution Approach 2:
The patent transitions from two-dimensional horizontal positioning (total station) to three-dimensional positioning including elevation (GNSS). The GNSS receiver provides vertical position data that enables accurate elevation measurement and grade control without line of sight requirements, allowing continuous operation in obstructed environments.
3Adaptability or versatility
If manual adjustment by operator is used for complex surfaces, then adaptability to different conditions is improved, but productivity decreases due to constant adjustment requirements
Solution Approach 1:
The patent implements a closed-loop feedback control system where the GNSS receiver continuously monitors the floating plate's position, the processor compares actual elevation with design surface information, and automatically adjusts the milling drum depth accordingly. This automated feedback loop provides adaptability to complex surfaces while eliminating manual adjustment time, significantly improving productivity.
Solution Approach 2:
The patent enables the milling machine to automatically adjust its own operation parameters based on real-time GNSS positioning data and design surface information. The system self-regulates the milling depth and elevation without requiring external manual intervention, combining adaptability with high productivity.
4Manufacturing precision
If floating plate with GNSS receiver and sensor is used to determine elevation and generate correction values, then manufacturing precision of milled surface is improved, but device complexity increases
Solution Approach 1:
The patent makes the floating plate a multi-functional element that serves as both a physical reference surface for sliding over the unmilled area and a mounting platform for the GNSS receiver and sensor. This universal design consolidates multiple functions into a single component, reducing overall system complexity while achieving high manufacturing precision.
Solution Approach 2:
The patent combines the GNSS receiver, sensor, and floating plate into an integrated positioning and control system. The processor merges data from the GNSS receiver (horizontal position) and sensor (vertical position) to calculate comprehensive elevation information, consolidating multiple measurement functions into a unified system that achieves high precision without excessive complexity.
Data Source
AI summary
In a method of milling asphalt, a relative elevation of an unmilled asphalt pavement surface adjacent to an area to be milled is sensed with respect to a milling machine body and rotatable milling drum of the milling machine. An elevation of a bottom surface of the rotatable milling drum is determined using a computer processor. Based on a map, stored in a computer memory, of a design surface specifying a design elevation of a milled surface over the area to be milled, the elevation of the milling machine body and the rotatable milling drum are automatically adjusted such that the rotatable milling drum mills the asphalt surface to the design elevation over the area to be milled.