Work Machine Braking Control With Deadband-Free Pedal Feedback
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Solution Overview
Problem
Work machines with multiple braking systems face challenges in providing consistent and reliable responses to operator inputs due to 'deadband' issues, where additional braking force is not applied until the pedal position exceeds a certain threshold, leading to inconsistent and uneasy operator experiences, especially in high-braking-demand scenarios like downhill operations.
Innovation Solution
A braking system with a controller that automatically applies braking force without operator input and provides force feedback through a dynamic pedal, ensuring no deadband by seamlessly transitioning between braking sub-systems, thus providing consistent and reliable machine response for the same operator input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If automatic braking features are implemented to apply braking force without operator input, then braking reliability is improved, but device complexity increases due to the need for intelligent control systems
Solution Approach 1:
The brake pedal assembly incorporates a force feedback mechanism that provides tactile feedback to the operator about the braking force being applied. This feedback loop allows the automatic braking system to communicate its action to the operator through the pedal, improving reliability by ensuring the operator is aware of automatic braking while maintaining a relatively simple mechanical feedback structure rather than requiring complex electronic interfaces.
2Force
If multiple braking sub-systems are used to handle high braking demands, then braking capability is improved, but deadband issues occur causing inconsistent operator experience
Solution Approach 1:
The system merges multiple braking sub-systems (electronic brake, exhaust brake, friction brake) into a unified braking control architecture. The controller seamlessly transitions between different braking sub-systems based on operating conditions, eliminating deadband by ensuring continuous braking force application. The force feedback mechanism on the pedal provides consistent tactile response regardless of which braking sub-system is active, improving operator experience consistency while maintaining high braking force capability.
Solution Approach 2:
The brake pedal assembly uses a dynamic force feedback mechanism that adjusts the tactile feedback characteristics based on the active braking sub-system and operating conditions. This dynamic adjustment ensures consistent operator perception and experience across different braking regimes, eliminating the deadband effect that would otherwise occur when transitioning between static braking force thresholds.
3Loss of information
If force feedback is provided through the brake pedal, then operator awareness is improved, but mechanical complexity of the pedal assembly increases
Solution Approach 1:
The brake pedal assembly incorporates a self-service force feedback mechanism where the actuator applies force directly to the pedal in response to braking commands. This mechanical self-service approach provides operator feedback information through the natural tactile sense of pedal resistance, improving operator awareness without requiring complex electronic displays or additional control interfaces. The system uses the existing pedal structure as the feedback delivery mechanism.
Data Source
AI summary
A work machine with a frame, an engine, a drivetrain powered by the engine, a ground-engaging member connected to the drivetrain, an operator cabin supported by the frame, a work implement, and a braking system connected to the ground-engaging member. The braking system including a brake input device located in the operator cabin for providing an input from an operator, at least one braking sub-system associated with the drivetrain, and a controller having at least one advanced braking feature, the braking system applying an automatic braking force in response to the at least one advance braking feature, and applying an additional progressive braking force in response to the input from the operator.