Hydraulic Excavator Blade Positioning Using Single GNSS Antenna
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Solution Overview
Problem
Hydraulic excavators with a blade face challenges in calculating the positional data of the blade using a GNSS antenna installed on a swing structure, as the positional relation between the swing structure and the blade changes during operation, potentially interfering with the antenna and being expensive, necessitating a system that can calculate blade position with a single antenna.
Innovation Solution
A hydraulic excavator system that includes a track structure, a swing structure with a work implement, a lift cylinder, a travelling lever, operation sensors, a height sensor, and a satellite positioning system antenna, where a controller calculates the blade's positional data by determining the track structure's orientation and blade height based on antenna data and stored relations, allowing for precise positioning without requiring multiple antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the GNSS antenna is installed on the blade, then the positional data can be obtained directly, but the soil scraped up by the blade and the work implement may interfere with the antenna
Solution Approach 1:
The GNSS antenna is extracted from the blade and relocated to the swing structure. This separation removes the antenna from the harmful environment created by soil and work implement interference, while still enabling positional data acquisition through the swing structure's movement characteristics
Solution Approach 2:
The swing structure serves as an intermediary carrier for the GNSS antenna. By mounting the antenna on the swing structure rather than directly on the blade, the system uses the swing structure's predictable movement pattern as a mediator to indirectly determine blade position through calculation rather than direct measurement
2Object-affected harmful factors
If the GNSS antenna is installed on the swing structure, then interference from soil and work implement is avoided, but the positional relation between the swing structure and the blade changes as the swing structure swings
Solution Approach 1:
The system performs preliminary action by storing in advance the positional relation data between the swing structure and the blade in a memory device. This pre-stored information enables the controller to calculate accurate blade position even though the actual positional relation changes during operation, as the calculation uses the known geometric relationship rather than direct real-time measurement
Solution Approach 2:
The system replaces the mechanical/direct measurement approach with an information-based calculation approach. Instead of directly measuring the blade position, the system uses GNSS data combined with pre-stored positional relation information and mathematical calculations to determine blade position, substituting physical measurement with computational derivation
3Measurement precision
If multiple GNSS antennas are installed to determine blade position, then positional data can be obtained accurately, but the system becomes more expensive
Solution Approach 1:
The single GNSS antenna on the swing structure serves multiple functions: it provides positional data for the swing structure itself, and through mathematical calculation using pre-stored positional relation information, it indirectly provides positional data for the blade. This multi-functionality eliminates the need for separate antennas on both the swing structure and the blade
Solution Approach 2:
The system creates a virtual copy of the blade's positional information through calculation rather than using a physical copy (second antenna). By mathematically deriving the blade position from the swing structure position and pre-stored geometric relationships, the system produces accurate positional data without requiring additional physical sensing equipment
Data Source
AI summary
In a hydraulic excavator including a track structure, a swing structure swingably disposed on an upper portion of the track structure, a work implement coupled to the swing structure, an earth removal device including a blade coupled to the track structure and a lift cylinder configured to raise and lower the blade, an operation sensor configured to detect an operation of a travelling lever, a height sensor configured to measure a height of the blade with respect to the track structure, an antenna for a satellite positioning system, the antenna being mounted on the swing structure, and a controller configured to calculate positional data regarding the blade, the controller is configured to determine a travelling operation on the basis of a signal of the operation sensor, calculate a travelling direction of straight forward travelling of the track structure as an orientation of the track structure when the straight forward travelling of the track structure is detected from a trajectory of the antenna with a state in which no turn travelling operation is being performed as a precondition, calculate horizontal coordinates of the blade on the basis of the orientation of the track structure, and calculate the height of the blade on the basis of a position of the antenna and a measured value of the height sensor.