Hydrostatic Transmission Straight-Tracking Control for Work Vehicles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Work vehicles with dual-path electronically controlled hydrostatic transmissions often veer off course due to manufacturing tolerances, hydraulic inefficiencies, and tire differences, despite operator inputs for straight travel, as existing systems fail to efficiently account for these variations.
Innovation Solution
A computer-implemented method and system that utilize speed sensors and a controller to modify speed signals with a speed scaling factor, adjusting control commands to ensure equal drive outputs on both sides, using a closed-loop control algorithm to maintain straight tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual trim adjustment is applied to joystick commands, then straight tracking can be achieved, but the system complexity increases and adjustment precision is limited
Solution Approach 1:
The patent implements a feedback mechanism where speed sensors continuously monitor the actual speeds of left and right drive systems, and the controller automatically adjusts pump commands based on detected speed differences. This closed-loop feedback eliminates the need for manual trim adjustments while maintaining straight tracking capability, thereby improving reliability without increasing device complexity.
Solution Approach 2:
The control system performs self-adjustment by automatically detecting speed asymmetries and correcting them through modified pump commands. The system serves itself by eliminating the need for operator intervention in trim adjustments, thereby achieving straight tracking without adding complex manual adjustment mechanisms.
2Measurement precision
If speed sensors and automated control are implemented, then tracking precision improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces manual mechanical adjustment mechanisms with an automated electronic control system. Speed sensors detect tracking deviations, and the controller automatically modifies hydraulic pump commands to correct the vehicle's path. This substitution of mechanical adjustment with electronic automation improves tracking precision while keeping the overall system complexity manageable through integration with existing hydraulic controls.
3Ease of operation
If equal joystick commands are provided for straight travel, then operator input is simple, but vehicle veering occurs due to manufacturing tolerances and hydraulic inefficiencies
Solution Approach 1:
The system maintains simple operator input through equal joystick commands while automatically compensating for veering through feedback from speed sensors. The controller detects speed differences between left and right drive systems and adjusts pump commands accordingly, thereby ensuring straight travel accuracy without complicating operator input.
Solution Approach 2:
The control system automatically corrects veering caused by manufacturing tolerances and hydraulic inefficiencies without requiring operator intervention. The system monitors drive system speeds and self-adjusts pump commands to maintain straight travel, thereby preserving ease of operation while improving straight travel accuracy.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for executing straight tracking control may include receiving an input command(s) associated with controlling the operation of a first-side drive system and/or a second-side drive system of a hydrostatic transmission of a work vehicle to drive the vehicle along a straight path. The method may also include receiving first and second speed signals associated with the output speeds of the drive systems, and modifying the first speed signal or the second speed signal based on a speed scaling factor to generate a corrected speed signal. In addition, the method may include determining an adjusted control command for controlling the operation of the hydrostatic transmission as a function of the input command(s) and a control output determined based on the corrected speed signal. Further, the method may include controlling the operation of the hydrostatic transmission based at least in part on the adjusted control command.