Biased Drive Control for Work Vehicle Traction in Turns
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Solution Overview
Problem
Existing work vehicles face issues with traction loss and spin-out conditions due to varying speeds of longitudinally offset wheels during turns, which are not effectively managed by mechanical differentials.
Innovation Solution
A drive system with a computing system that adjusts the differential shaft ratios of front and rear axles based on wheel sensor data to maintain equal traction and prevent wheel overpowers or underpowers, ensuring each wheel rotates at the appropriate speed for the commanded trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical differential is used to regulate wheel speeds during turns, then lateral wheel speed differences are accommodated, but longitudinal wheel speed variations cause traction loss and spin-out conditions
Solution Approach 1:
The patent replaces the purely mechanical differential system with a hybrid system that incorporates electronic sensors and a controller. The controller receives signals from wheel speed sensors and actively adjusts differential shaft ratios through actuation mechanisms, substituting passive mechanical speed regulation with active electronic control to maintain optimal traction during turns
Solution Approach 2:
The system dynamically adjusts the differential shaft ratios based on real-time wheel speed measurements and commanded trajectory data. The controller continuously modifies the speed relationship between front and rear axles to accommodate varying longitudinal wheel speed requirements during turning maneuvers, transforming a static mechanical differential into a dynamic, adaptive system
2Ease of operation
If longitudinal wheel speed variations are allowed during turns, then turn execution is facilitated, but traction loss and spin-out conditions occur
Solution Approach 1:
The system employs wheel speed sensors that continuously monitor actual wheel speeds and feed this information back to the controller. The controller compares measured speeds against expected speeds based on commanded trajectory, and actively adjusts differential shaft ratios to correct deviations, maintaining optimal traction while accommodating necessary speed variations for turn execution
3Device complexity
If equal shaft ratios are maintained between front and rear axles, then mechanical simplicity is preserved, but wheel overpowers or underpowers occur during turns
Solution Approach 1:
The system transforms the static, equal shaft ratio configuration into a dynamic system where the controller actively adjusts front and rear differential shaft ratios based on real-time operating conditions. During turns, the controller differentially adjusts shaft ratios to optimize power distribution to each axle, preventing wheel overpowers or underpowers while maintaining overall system coordination
Solution Approach 2:
The system changes the shaft ratio parameter dynamically based on commanded trajectory and actual wheel speed measurements. The controller modifies the speed ratio between front and rear axles as a controllable parameter, adjusting it to accommodate varying longitudinal wheel speed requirements during different phases of turning maneuvers, thereby optimizing power distribution and preventing wheel slip
Data Source
AI summary
A drive system for a work vehicle includes a chassis, a first front wheel and a second front wheel operably coupled with a front axle assembly, and a first rear wheel and a second rear wheel operably coupled with a rear axle assembly. At least one wheel sensor can be associated with the first front wheel, the second front wheel, or both. A transfer case can be operably coupled with a front differential input shaft and a rear differential input shaft. A computing system can be operably coupled with the at least one wheel sensor and the transfer case. The computing system can be configured to receive an input related to a commanded vehicle trajectory, determine a correlation of a front axle reference point to a rear axle reference point, and determine a differential shaft ratio based at least partially on the correlation.