Grade Control Using Stereo Camera and IMU
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Solution Overview
Problem
Conventional grade control systems for work machines rely on vulnerable sonic sensors and GPS, which can be damaged and lack precision, limiting machine operations and increasing theft risks.
Innovation Solution
Integration of stereo camera technology and onboard inertial measurement units (IMUs) for local reference system-based grade control, eliminating the need for sonic sensors and GPS, allowing for precise control of work implements relative to terrain features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sonic sensors are mounted on the work machine blade or screed, then grade control measurement is achieved, but the sensors are vulnerable to damage and theft
Solution Approach 1:
The patent removes the sonic sensors from the vulnerable location on the blade or screed and relocates them to the operator's station, protecting them from damage while maintaining their measurement function through the use of a camera system that captures images of the terrain feature
Solution Approach 2:
Instead of using physical sonic sensors in direct contact with the terrain, the system creates an optical copy or image of the terrain feature using a camera, and processes this visual information to achieve grade control without exposing physical sensors to damage
2Measurement precision
If GPS integration is used for grade control, then global reference system is provided, but precision is insufficient for some work contexts
Solution Approach 1:
The patent transitions from using GPS satellite-based positioning (three-dimensional space) to using a camera-based visual measurement system that captures two-dimensional images of terrain features, which are then processed to extract precise position and elevation information in the local reference system
Solution Approach 2:
The system introduces an intermediary element - a camera system with image processing capabilities - between the work machine and the terrain feature, allowing precise measurement of terrain features like curbs without direct sensor contact or reliance on GPS satellite signals
3Adaptability or versatility
If mast and sonic sensors are used for grade control, then terrain reference is achieved, but machine operations are substantially limited
Solution Approach 1:
The patent creates a universal grade control system that can measure various terrain features (curbs, string lines, existing surfaces) using a single camera-based platform, allowing the work machine to perform multiple operations including rotating and pitching the blade without being constrained by physical sensor mounting requirements
Solution Approach 2:
The system replaces the mechanical mast and sonic sensor assembly with an optical camera system and digital image processing, eliminating the need for physical structures that limit machine movement and enabling greater operational versatility
Data Source
AI summary
A work machine is provided with grade control capability using an imaging system, e.g., rather than GPS. The work machine includes at least one work implement for working at least part of a terrain, and first sensors (e.g., cylinder sensors) generate signals corresponding to positions of the work implement. Second sensors (e.g., stereo cameras) generate signals corresponding to positions of representative features of the terrain (e.g., curbs) in a field of view. A controller receives the signals and determines in a local reference system independent of a global reference system: first position information corresponding to the work implement; and second position information corresponding to the representative features. According to a selected control mode, target parameters for the work implement are determined based on the second position information corresponding to the representative features, and output signals are generated corresponding to a difference between the first position information and the target parameters.