Dynamic Reference Point Control for Construction Machine Path Following
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Solution Overview
Problem
Existing self-propelled construction machines, such as slipform pavers, face challenges in automatically transitioning from straight to curved sections of a predetermined route, leading to erratic steering and difficulties in maintaining precise control, especially when entering tight curves or changing the working direction.
Innovation Solution
The solution involves continuously shifting the position of reference points used for controlling the drive unit within a coordinate system related to the machine, from a front position to a rear position before entering a curve and back to a front position after exiting the curve, allowing for smoother transitions and precise guidance along the target path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the construction machine uses fixed reference points for control, then the control system is simple, but the machine cannot accurately follow curved sections of the route
Solution Approach 1:
The reference point position is made dynamic rather than fixed. The control system continuously adjusts the reference point location along the machine's longitudinal axis based on the curvature of the target route, enabling accurate following of both straight and curved sections without requiring multiple physical sensors or complex switching mechanisms
Solution Approach 2:
The system changes the parameter of reference point position dynamically. By calculating the optimal reference point location based on route curvature parameters, the system adapts the control geometry to match the target path characteristics, improving following precision while maintaining a single fixed physical sensor
2Adaptability or versatility
If the machine switches between different feeler elements for straight and curved sections, then it can adapt to different route geometries, but the control process becomes discontinuous and erratic
Solution Approach 1:
Instead of switching between discrete fixed reference points, the system dynamically calculates a continuous reference point position that smoothly transitions as the machine moves along the route. This eliminates discontinuities and erratic behavior while maintaining adaptability to changing route geometries
Solution Approach 2:
The control system preliminarily calculates the optimal reference point position based on predicted route curvature before the machine reaches curved sections. This proactive adjustment ensures smooth transitions and continuous control without reactive switching that causes instability
3Ease of operation
If the middle feeler element is used for curved sections, then the control can be simplified, but the position control accuracy decreases due to dependency on curve radius
Solution Approach 1:
The system changes the reference point position parameter dynamically based on route curvature rather than using a fixed middle position. This maintains control simplicity with a single reference point while improving position accuracy by adapting the reference point location to match the specific curvature requirements of each section
Data Source
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Figure 3.2
AI summary
The construction machine has determining unit to determine deviation of reference point of construction machine with respect to target path. The control unit controls drive unit based on deviation of reference point of construction machine with respect to target path so that reference point on set travel distance or predetermined distance along target path is moved. The control and computing unit varies position of reference point during movement of construction machine in accordance with course of target path in construction machine related coordinate system. An independent claim is included for method for controlling drive unit of self-propelled construction machine.