Four-Wheel Steering Control for Cross-Track and Yaw Correction
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Solution Overview
Problem
Agricultural machines face challenges in correcting cross-track and track-angle errors while minimizing vehicle rotation, leading to reduced productivity and potential damage to equipment due to dynamic movement and oscillations when switching between steering modes, which requires different tuning parameters and complex steering algorithms.
Innovation Solution
A steering controller that independently steers each axle to correct positional and rotational errors relative to a guidance path using shared tuning parameters, converting input parameters to a common unit through a control model based on vehicle behavioral parameters, allowing dynamic switching between steering modes without requiring different code bases or tuning sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional single-mode steering control is used, then the steering algorithm is simple, but the machine cannot efficiently handle both near-path and far-path correction scenarios
Solution Approach 1:
The patent implements a universal steering controller that can operate in multiple steering modes (single-axle and dual-axle) using the same control algorithm and tuning parameters. The controller automatically selects the appropriate steering mode based on machine configuration, eliminating the need for separate control systems for different steering scenarios and achieving multi-functionality without proportional increase in complexity.
Solution Approach 2:
The patent enables dynamic switching between different steering modes during operation. The controller can transition between single-axle and dual-axle steering modes based on real-time conditions such as path deviation magnitude, allowing the system to adapt its steering behavior dynamically rather than being locked into a fixed steering configuration.
2Reliability
If different tuning parameters are used for different steering modes, then each mode can be optimized, but the machine characterization becomes complex and switching between modes requires different code bases
Solution Approach 1:
The patent employs parameter adaptation within a unified control framework. Instead of using completely different tuning parameters for different steering modes, the system adjusts specific parameter values based on the active steering mode while maintaining the same underlying control algorithm. This approach allows optimization for each mode while avoiding the complexity of multiple code bases and extensive machine characterization.
Solution Approach 2:
The patent segments the steering control into distinct operational phases (single-axle steering phase and dual-axle steering phase) that can be activated based on current needs. Each phase uses appropriate control parameters for that specific scenario, but both phases are managed by the same overall control system, reducing the need for comprehensive machine characterization across all possible modes simultaneously.
3Ease of operation
If the machine traverses large areas during row transitions, then it can reach the next crop row, but it causes significant dynamic movement in equipment, wastes time, and consumes agricultural products
Solution Approach 1:
The patent applies preliminary steering actions to guide the machine along an optimal curved path during row transitions. By pre-calculating and executing the appropriate steering sequence before the machine reaches the transition zone, the system minimizes unnecessary traversal distance and reduces dynamic movements during critical transition phases, thereby improving operational efficiency and reducing agricultural product waste.
4Speed
If high yaw rate is used during row transitions, then the machine can quickly change direction, but it causes whipping of implements and stresses the equipment
Solution Approach 1:
The patent implements periodic or pulsed steering corrections during row transitions rather than continuous high-intensity steering. By applying steering inputs in controlled pulses or periodic sequences, the system achieves necessary direction changes while allowing the implement to settle between corrections, reducing whipping effects and structural stress on equipment.
Data Source
AI summary
A device for steering an agricultural machine having independently steerable axles includes first and second steerable axle interface to couple with a first steering mechanism of a first steerable axle and a second a second steering mechanism of a second steerable axle. The device includes a planning module having a guidance path for the agricultural machine, and a steering control module to coordinate steering of the steering mechanisms. The steering control module includes a translational comparator to determine a translational difference between a location of the agricultural machine relative to the guidance path, an angular comparator to determine an angular difference between an angular orientation of the agricultural machine relative to the guidance path, and a translation steering controller to actuate the first and second steering mechanisms according to the translational difference. The device includes an angular steering controller to actuate the second steering mechanism according to the angular difference.