Steerable Axle Calibration Using Sensor Feedback
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Solution Overview
Problem
The calibration of steerable axles in towed or self-propelled commercial vehicles, such as agricultural tractor-trailer combinations, is complex and error-prone due to manual methods, which can lead to inaccuracies and increased tire wear from mechanical tolerances in the hitch coupling.
Innovation Solution
An automated method for calibrating the positions of end stops and straight-ahead travel positions of steerable axles, using sensors and control devices to determine and adjust axle positions both when stationary and during straight travel, ensuring accurate and error-free calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manual calibration methods are used for steerable axles, then calibration can be performed with simple equipment, but the calibration process becomes complex and error-prone
Solution Approach 1:
The calibration system uses the vehicle's own sensors (drawbar angle sensor, axle angle sensors) and control device to automatically determine end stop positions and straight-ahead positions without external equipment like lasers or alignment beams. The control device autonomously processes sensor signals to calculate calibration data, making the system self-calibrating and eliminating manual intervention errors.
Solution Approach 2:
The patent replaces manual mechanical calibration methods (using lasers, alignment beams, and physical positioning) with an automated sensor-based electronic system. The drawbar angle sensor and axle angle sensors electronically detect positions, and the control device computationally determines calibration parameters, substituting mechanical precision tools with electronic measurement and calculation.
2Measurement precision
If automated calibration is implemented, then calibration accuracy improves, but system complexity increases
Solution Approach 1:
The control device performs multiple functions: it controls the steerable axles during active steering mode, processes signals from the drawbar angle sensor and axle angle sensors, determines end stop positions, calculates straight-ahead positions, and generates calibration data. By making the control device multi-functional, the patent avoids adding separate dedicated calibration equipment, thus improving precision without proportionally increasing system complexity.
Solution Approach 2:
The system continuously monitors the actual positions of the steerable axles using axle angle sensors and compares them with target positions (end stops and straight-ahead positions). The control device uses this feedback to automatically adjust and refine calibration data, ensuring high measurement precision through iterative correction rather than requiring overly complex initial calibration mechanisms.
3Productivity
If manual calibration is performed, then equipment requirements are minimal, but time consumption and labor increase
Solution Approach 1:
The system performs preliminary detection of end stop positions using the drawbar angle sensor and axle angle sensors before final calibration is needed. The control device pre-calculates straight-ahead positions based on detected end stop positions, so that when calibration is required, the system can quickly apply pre-computed calibration data without time-consuming manual measurements or iterative adjustments.
Data Source
Figure 1~2
AI summary
Method for calibrating a towed or self-propelled commercial vehicle (3) with at least one steerable axle (9) or a combination (1) of a self-propelled commercial vehicle designed as a towing vehicle (2) and a towed commercial vehicle designed as a trailer (3) with at least one steerable axle (9), namely for calibrating at least the positions for the end stops and for straight-ahead travel of the or each steerable axle (9) of the commercial vehicle (3), wherein, when the commercial vehicle (3) is stationary, the end stops of the or each steerable axle (9) of the commercial vehicle (3) are automatically approached and the positions of these end stops are automatically determined for calibration; wherein, for the or each steerable axle (9) of the commercial vehicle (3), a preliminary position for straight-ahead travel of the respective steerable axle (9) is automatically determined from the positions of the end stops by averaging;and wherein, when, during a straight-ahead journey of the commercial vehicle (3) in a plane, the or each steerable axle (9) of the commercial vehicle (3) is released in such a way that it passively engages during the straight-ahead journey, a final position for the straight-ahead journey of the respective steerable axle is automatically determined for calibration.