Slipform Paver Trajectory Control During GNSS Signal Loss
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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, such as behind buildings or in tunnels, leading to loss of positioning and control capabilities.
Innovation Solution
The machine is equipped with steerable and drivable running gears, a position-determining device that includes a GNSS receiver and a processor for independent coordinate system positioning, and a controller that switches to a kinematic model-based control mode when GNSS signals are inadequate, using steering angle and speed sensors to maintain trajectory accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS receiver is used for position determination, then positioning accuracy is improved, but reliability deteriorates when satellite signals are disrupted
Solution Approach 1:
The system changes the control parameter source from GNSS satellite signals to a kinematic model based on steering angle and speed data when signal availability changes. This parameter substitution ensures continuous operation by switching between different measurement sources depending on environmental conditions.
Solution Approach 2:
The kinematic model acts as an intermediary between the lost GNSS positioning function and the control system. It uses available sensor data (steering angle, speed) to compute position and orientation, serving as a bridge that maintains control functionality when direct satellite signals are unavailable.
2Extent of automation
If automatic control based on GNSS is implemented, then driver intervention is reduced, but control capability is lost when satellite signals are blocked
Solution Approach 1:
The control system dynamically adapts its operation mode based on GNSS signal availability. It transitions from fully automatic GNSS-based control to kinematic model-based control when signals are blocked, and can switch back when signals are restored. This dynamic adaptability maintains automation while ensuring continuous control capability.
Solution Approach 2:
The system prepares alternative control methods (kinematic model) in advance to cushion against potential GNSS signal disruptions. By having a backup control strategy ready, the system prevents complete loss of control capability when satellite signals are blocked by buildings or terrain.
3Reliability
If kinematic model is used instead of GNSS, then reliability is improved during signal disruption, but measurement precision may deteriorate
Solution Approach 1:
The system continuously monitors GNSS signal availability and feedback-controlledly switches between control modes. When signal disruption is detected, it transitions to the kinematic model; when signals are restored, it switches back to GNSS-based control. This feedback mechanism ensures the system uses the most accurate available method at any given time.
Solution Approach 2:
The control system is designed to perform multiple functions using different methods: GNSS-based positioning when available, and kinematic model-based positioning when GNSS is unavailable. This multi-functionality allows the system to maintain reliability across varying operational conditions while minimizing precision loss by using the appropriate method for each situation.
Data Source
AI summary
The invention relates to a self-propelled construction machine and to a method for controlling a self-propelled construction machine. The construction machine according to the invention has a position-determining 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. The position-determining device has a navigation satellite system receiver 14 for receiving satellite signals from a global navigation satellite system 15 (GNSS) and a computing unit 16 which is configured so that the position of a reference point (R) on the construction machine and the orientation (ψ) of the construction machine can be determined based on the satellite signals in a coordinate system (X, Y, Z) that is independent of the construction machine. Moreover, the construction machine has a controller 18 which cooperates with the position-determining device 13 configured to adjust the steering angles of the steerable running gears 3, 4, 6 so that the reference point R of the construction machine moves along a set trajectory T. The computing unit 16 of the position-determining device 13 is configured so 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) relating to the construction machine and the orientation (ψ) of the construction machine are determined in the coordinate system (X, Y, Z) that is independent of the construction machine while the construction machine is moving on the basis of a kinematic model 16A implemented in the computing unit 16 of the position-determining device 13 which describes the position (P) of the reference point (R) and the orientation (ψ) in the coordinate system (X, Y, Z) that is independent of the construction machine depending on the steering angles and the speeds of the running gears 3, 4, 6.