Construction Machine Trajectory Control Without GNSS Signals
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Solution Overview
Problem
Self-propelled construction machines face challenges in maintaining accurate trajectory control when Global Navigation Satellite System (GNSS) signals are disrupted, leading to loss of position determination and requiring machine shutdown.
Innovation Solution
The machine employs a position determination device with a kinematic model that calculates the position and orientation of the construction machine using steering angle and speed sensors, allowing it to continue moving along a predetermined trajectory even without GNSS signals by compensating for factors like slippage and terrain interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS signals are used for position determination, then trajectory control accuracy is improved, but operation is interrupted when signals are disrupted
Solution Approach 1:
The system changes the position determination method parameter from GNSS-based to kinematic model-based when signal availability changes. The arithmetic unit switches between different determination parameters (GNSS coordinates vs. calculated coordinates from kinematic model) to maintain continuous operation while preserving accuracy where possible.
Solution Approach 2:
The kinematic model acts as an intermediary between the lost GNSS signals and the control system. When GNSS signals are unavailable, the kinematic model using steering angle and speed sensor data serves as a substitute position determination mechanism, allowing the control device to continue guiding the machine along the trajectory.
2Reliability
If kinematic model is used for position determination, then continuous operation is maintained, but measurement precision may be reduced compared to GNSS
Solution Approach 1:
The control device continuously receives feedback from sensors (steering angle, speed) and uses this feedback in the kinematic model to calculate current position. This closed-loop feedback mechanism maintains position determination accuracy by constantly updating the model with actual machine state data, compensating for potential drift or accumulation of errors.
Solution Approach 2:
The system performs preliminary determination of correction amounts for the kinematic model before full signal loss occurs. By pre-calculating and storing correction values when GNSS signals are still available, the system prepares the kinematic model for accurate operation during signal disruption, reducing the precision gap between GNSS and kinematic modes.
3Productivity
If automatic control is implemented, then productivity is improved, but system complexity increases
Solution Approach 1:
The control device is designed with multi-functionality, serving both as a GNSS signal processor and a kinematic model calculator. This universal control unit handles multiple functions (signal reception, position calculation, trajectory guidance, sensor data processing) within a single system, reducing overall device complexity despite the sophisticated automatic control capabilities.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
The construction machine has a positioning device 13 for determining the position of a reference point R on the construction machine in a coordinate system (X, Y, Z) independent of the construction machine, a navigation satellite system receiver 14 for receiving satellite signals from a global navigation satellite system 15 (GNSS), as well as a computing unit 16 and a control device 18.The computing unit 16 is configured such that, in a control mode in which the control of the construction machine is not based on the satellite signals of the global navigation satellite system 15, the position (xn, yn, zn) of the reference point R related to the construction machine and the orientation (ψ) of the construction machine in the coordinate system (X, Y, Z) independent of the construction machine are determined during the movement of the construction machine on the basis of a kinematic model 16A implemented in the computing unit 16, which describes the position (P) of the reference point R and the orientation (ψ) of the construction machine in the coordinate system (X, Y, Z) independent of the construction machine as a function of the steering angles and the speeds of the drives 3, 4, 6.