Work Vehicle Creep Derating for Steering and Reverse Control
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Solution Overview
Problem
Conventional self-propelled work vehicles, such as skid steer loaders, face issues with undesirably slow reverse speed and underpowered steering when using certain attachments like dozer blades due to the universal application of scalar derate values to drivetrain speed commands, which limits the effectiveness of creep mode.
Innovation Solution
A novel system and method for selectively applying creep derate values to propulsion and steering drivetrain commands independently, allowing for separate derate settings for forward and reverse motion, and enabling or disabling creep functionality based on attachment types and work states detected by onboard sensors and user interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a universal scalar derate value is applied to drivetrain speed commands in creep mode, then forward propulsion speed is reduced for precision work, but steering power becomes underpowered
Solution Approach 1:
The patent separates steering commands from propulsion commands and applies derate values independently to each segment. Steering portion of the drivetrain command is excluded from the creep derate application, maintaining full steering power while still achieving reduced forward propulsion speed for precision work
Solution Approach 2:
Different derate characteristics are applied locally to different functional areas: the propulsion portion receives the creep derate for precision control, while the steering portion maintains full power. This ensures steering remains responsive and powerful even when forward motion is deliberately slowed
2Ease of operation
If creep functionality is universally applied to all drivetrain commands, then operational simplicity is maintained, but adaptability to different attachments and work states is reduced
Solution Approach 1:
The patent implements dynamic creep functionality that automatically adjusts based on detected attachment types and work states. The control system monitors sensor inputs and modifies derate application in real-time, enabling the system to adapt to different attachments (e.g., dozer blades) and work conditions without requiring manual reconfiguration, thus maintaining ease of operation while enhancing adaptability
Solution Approach 2:
The patent incorporates feedback mechanisms through onboard sensors that detect attachment presence and work state conditions. This feedback enables the control system to automatically adjust creep derate application, providing adaptability to different attachments and work states while maintaining operational simplicity through automated control
Data Source
AI summary
A method is provided for controlling a self-propelled work vehicle comprising a work attachment and at least left and right ground engaging units driven by respective first and second drivetrains. Upon determining transition from a first operating mode to a second operating mode (e.g., creep mode), the method includes selectively derating at least a portion of the drivetrain speed commands corresponding to propulsion of the work vehicle (e.g., the average of left and right track speeds), independent of a portion of the drivetrain speed commands corresponding to steering (e.g., the difference between the track speeds). The derate value may optionally be applied only to propulsion commands that produce forward motion, and not for reverse motion. Separate (non-zero) derate settings may optionally be provided for reverse and/or steering functions. Derate functionality may optionally be implemented upon detecting particular types (e.g. dozer) of attachments, or an associated work state.