Dual Path Vehicle Steering via Differential Braking
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Solution Overview
Problem
Dual path vehicles face loss of steering control in emergency situations due to motor or pump failures, causing them to veer from their intended course when coming to a stop, as the propel system, which also serves as the steering system, fails to function properly.
Innovation Solution
A steering system that includes a propulsion controller and a brake controller, where the brake controller takes over steering control by applying differential brake pressures to the left and right brakes based on the position of the steering and brake elements, providing redundant steering in case of a machine failure detected by sensors monitoring the propulsion or brake systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the propel system serves as both propulsion and steering system in dual path vehicles, then the vehicle structure is simplified and cost reduced, but steering control is lost entirely when motor or pump failure occurs
Solution Approach 1:
The brake system is designed to perform dual functions: its primary function of slowing/stopping the vehicle, and a secondary function of providing emergency steering control. By making the brake system multi-functional, the patent eliminates the need for a separate dedicated steering system while maintaining steering capability during propulsion system failures.
Solution Approach 2:
The control system dynamically changes the operational parameters of the brake system. During normal operation, brakes apply equal force to both sides. During emergency steering, the controller creates differential brake pressure between left and right sides by modulating brake cylinder pressure, enabling the vehicle to turn even during propulsion system failure.
2Reliability
If separate dedicated propel and steering systems are used, then steering control reliability is maintained during propulsion failures, but device complexity and cost increase
Solution Approach 1:
The brake system is designed to perform dual functions: its primary function of slowing/stopping the vehicle, and a secondary function of providing emergency steering control. By making the brake system multi-functional, the patent eliminates the need for a separate dedicated steering system while maintaining steering capability during propulsion system failures.
3Reliability
If differential brake pressures are applied for emergency steering, then steering control is maintained during propulsion failures, but brake system wear and heat generation increase
Solution Approach 1:
The control system detects propulsion system failures early and activates the brake-based emergency steering system before complete steering control is lost. By anticipating the failure and switching to the backup steering method proactively, the system maintains continuous steering capability while limiting brake wear to only emergency situations.
Solution Approach 2:
The system continuously monitors propulsion system status through sensors and control signals. When a failure is detected, the feedback loop triggers automatic switching to brake-based steering control, ensuring seamless transition and maintaining steering reliability while minimizing unnecessary brake activation and wear.
Data Source
AI summary
According to the present disclosure, a system for providing steering control in a dual path machine includes a propulsion controller operatively connected to plants of the machine for driving ground contacting elements, the propulsion controller being configured to control steering of the dual path machine through drive signals sent to the plants, and a brake controller operatively connected to left and right brakes of the machine, the brake controller being configured to control steering of the machine by providing differential brake pressures to the left and right brakes. The system of the present disclosure provides redundant steering control by receiving an input signal at the brake controller with an indication of steering position, receiving an input signal at the brake controller with an indication of brake position, and providing a differential brake pressure to brakes of the dual path machine based on the steering input signal and brake input signal.