Vehicle Front Dig Torque Control for Tight Turning
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Solution Overview
Problem
Modern vehicles are limited by a large turn radius, making it difficult to navigate tight corners, as they rely on traditional steering and torque application to two wheels.
Innovation Solution
The implementation of a front dig mode and tank-turn mode, utilizing independent control of front and rear drive shafts, wheels, and brakes, allowing for reduced turn radius through specific torque and braking strategies managed by on-board processing circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional steering and torque application to two wheels is used, then the vehicle structure is simple and reliable, but the turn radius is large making it difficult to navigate tight corners
Solution Approach 1:
The vehicle's drive system is segmented into four independently controllable wheels, allowing each wheel to receive individual torque commands. This segmentation enables the front dig mode where only the front wheels receive forward torque while rear wheels receive backward torque, creating a pivoting effect that reduces turn radius without requiring complex mechanical steering modifications
Solution Approach 2:
The control system dynamically adjusts torque distribution to each wheel based on operating conditions. In front dig mode, the system applies forward torque to front wheels and backward torque to rear wheels, creating a dynamic torque vectoring effect that enables tight turning. The system can transition between different driving modes (normal driving, front dig mode, tank turn mode) based on real-time conditions
2Ease of operation
If independent control of all four wheels with torque vectoring is implemented, then the turn radius is reduced improving maneuverability, but the control system complexity increases
Solution Approach 1:
The independent wheel control system serves multiple functions: normal driving mode, front dig mode for tight corners, and tank turn mode for extreme maneuvering. This multi-functionality justifies the increased system complexity by providing versatile operational capabilities across different driving scenarios without requiring separate systems for each mode
Solution Approach 2:
The system changes torque parameters independently for each wheel based on the selected operating mode. In front dig mode, front wheels receive positive torque while rear wheels receive negative torque. The control system monitors wheel speeds, steering angle, and vehicle state to dynamically adjust these parameters, enabling precise control of turn radius and vehicle orientation
3Ease of operation
If front dig mode with differential torque application is used, then the turn radius decreases enabling tight corner navigation, but the energy consumption increases due to opposing torque on rear wheels
Solution Approach 1:
The front dig mode applies torque only to the necessary wheels (front wheels for forward motion, rear wheels for pivoting resistance) rather than all four wheels simultaneously. This partial action reduces energy consumption compared to applying full torque to all wheels, while still achieving the tight turning effect by creating a moment arm through differential torque application
Data Source
AI summary
Systems and methods are provided herein for operating a vehicle in a front dig mode. The front dig mode is engaged in response to determining that speed of the vehicle is below a speed threshold and determining that the amount that at least one of the front wheels of the vehicle is turned exceeds a turn threshold. While operating in the front dig mode, forward torque is provided to the front wheels of the vehicle. Further, resistance is applied to forward rotation of the inner back wheel of the vehicle. Yet further, forward torque is provided to the outer back wheel of the vehicle.