Construction Machine GNSS Smoothing for Accurate Posture Tracking
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Solution Overview
Problem
Construction machines, such as hydraulic excavators, face challenges in maintaining accurate positioning and posture information due to changes in satellite positioning environments and movements without operator intervention, leading to inefficiencies in machine guidance and control.
Innovation Solution
A construction machine equipped with multiple sensors and a computing device that performs two-stage smoothing processing on positioning data, adjusting for satellite positioning changes and machine motion, to maintain accurate posture information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS positioning is used to obtain position information, then position data can be acquired, but positioning accuracy deteriorates when the number of available satellites is small
Solution Approach 1:
The system changes the parameter of smoothing strength dynamically based on the number of available satellites. When satellite availability is low, the smoothing strength is increased to maintain positioning accuracy. This is achieved by adjusting the smoothing coefficient or filter parameters according to the satellite count, transforming a static smoothing approach into a dynamic one that adapts to varying satellite conditions.
2Measurement precision
If smoothing processing is applied to positioning data, then positioning accuracy is improved, but response to actual machine movement is delayed
Solution Approach 1:
The system makes the smoothing strength dynamic rather than static. The smoothing coefficient is adjusted in real-time based on the number of available satellites and the variance of positioning data. When satellite conditions are good, smoothing is reduced to improve response speed. When satellite conditions deteriorate, smoothing is increased to maintain accuracy. This dynamic adjustment resolves the contradiction between accuracy and response time.
Solution Approach 2:
The system uses feedback from the positioning data variance and satellite availability to continuously adjust the smoothing strength. The variance of positioning results is calculated and fed back to modify the smoothing coefficient, creating a closed-loop control system that automatically balances accuracy and response time based on current conditions.
3Measurement precision
If work device motion is monitored to detect machine movement, then movement detection accuracy is improved, but system complexity increases
Solution Approach 1:
The system uses the work device motion as an intermediary indicator to detect machine body movement. Instead of directly monitoring the machine body, it infers movement from the work device's motion state. This intermediary approach provides accurate movement detection while avoiding the complexity of installing additional sensors on the machine body.
4Stability of the object's composition
If strong smoothing is applied to eliminate positioning variation, then positioning stability is improved, but accuracy of detecting actual machine movement is reduced
Solution Approach 1:
The system dynamically adjusts smoothing strength based on the variance of positioning data and satellite availability. When positioning variance is high (indicating poor satellite conditions), stronger smoothing is applied to eliminate variation. When variance is low (good satellite conditions), weaker smoothing is applied to preserve movement detection accuracy. This dynamic adaptation resolves the contradiction between stability and movement detection precision.
Solution Approach 2:
The smoothing parameter is changed based on the variance of positioning results. The system calculates the variance and uses it to modulate the smoothing coefficient, transforming a fixed smoothing parameter into a variable one that adapts to the quality of positioning data and the actual movement state.
Data Source
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AI summary
A construction machine includes: a work device attached to a machine body in a raiseable and lowerable manner; an antenna that is attached to the machine body and receives positioning signals from satellites; a machine body IMU that senses information on a posture and motion of the machine body; an IMU that senses information on a posture of the work device; and a computing device that computes posture information indicating the postures of the machine body and the work device. The computing device performs positioning computation that is to compute a position of the machine body and a variance value thereof based on the positioning signals received by the antenna, subjects the position as a result of the positioning computation to first smoothing processing that is to increase a degree of smoothing as the variance value as a result of the positioning computation becomes larger, and computes the posture information based on a result of the first smoothing processing and the information sensed by the machine body IMU and the IMU.