Steering Paddle Control for Off-Road Crawl and Tank Turns
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Solution Overview
Problem
Vehicles face challenges in maneuverability and traction on difficult off-road terrain, particularly when wheels lose traction, leading to inability to move forward or backward.
Innovation Solution
A vehicle with four-wheel steering capabilities and a controller that executes specific wheel steering and driving sequences, including diagonal driving, forward and reverse crawl operations, and tank-turn modes, to enhance maneuverability and traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional two-wheel steering is used, then the vehicle structure is simple, but the vehicle cannot maneuver effectively on difficult off-road terrain when wheels lose traction
Solution Approach 1:
The steering system is segmented into independent front and rear steering actuators, allowing each axle to be controlled separately. This enables four-wheel steering capabilities where front and rear wheels can be steered in different directions and angles, providing enhanced maneuverability on difficult terrain while maintaining a modular architecture that manages complexity
Solution Approach 2:
The steering system transitions from static two-wheel steering to dynamic four-wheel steering with variable steering angles. The front and rear steering actuators can independently adjust wheel angles based on terrain conditions, enabling adaptive maneuvering strategies such as crabbing, tank turning, and diagonal driving modes
2Adaptability or versatility
If four-wheel steering actuators are added for off-road capability, then the vehicle can traverse difficult terrain, but the device complexity increases
Solution Approach 1:
The four-wheel steering system provides multiple functions beyond traditional steering: it enables crabbing mode for lateral movement, tank turning for rotation in place, diagonal driving for enhanced traction, and conventional steering for normal operation. This multi-functionality justifies the added complexity by providing a single system that handles various off-road scenarios
Solution Approach 2:
The front and rear steering systems are merged into a coordinated four-wheel steering control architecture. The controller integrates inputs from both steering actuators and coordinates their operation to achieve complex maneuvers that would be impossible with independent systems, optimizing the complexity-to-capability ratio
3Force
If wheel forces are increased to improve traction, then the vehicle can move forward, but the wheels may lose traction on difficult terrain
Solution Approach 1:
The vehicle transitions from forward-only propulsion to multi-directional movement capabilities. By enabling lateral crabbing motion and diagonal driving modes, the vehicle can move in directions that optimize traction by engaging different ground surfaces, effectively adding dimensional freedom to force application
Solution Approach 2:
Instead of increasing forward wheel force to overcome lack of traction, the system inverts the approach by applying lateral forces through crabbing mode or diagonal forces through angled wheel positioning. This redirects the force vector to engage different ground contact points that may provide better traction
Data Source
AI summary
A vehicle comprising a steering-wheel assembly, left and right driver-actuatable paddles supported by the steering wheel assembly and each including a variable-force sensor; and a controller. The controller is programmed to command one of: (i) a steering angle to a steering actuator according to a force applied to one of the paddles such that the steering angle increases as the force applied increases, or (ii) command a speed to left and right wheels according to a force applied to one of the paddles such that a differential between the speed commanded to the left wheel and the speed commanded to the right wheel increases as the force applied increases.