Vehicle Torque Control for Sand Mode Side Slip
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Solution Overview
Problem
Off-road vehicles face challenges in maintaining traction and inducing side slip while driving in sand, as traditional four-wheel drive modes can limit forward momentum and make it difficult to achieve desired side slip due to torque distribution issues between the front and rear axles.
Innovation Solution
The method involves operating both propulsion sources in torque control mode, increasing the proportion of driver-demand wheel torque to the rear axle when a steering angle exceeds a threshold to induce side slip, while reducing it if side slip exceeds a threshold level and increasing torque to the front axle, thereby maintaining tractive effort and controlling side slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the vehicle operates in four wheel drive mode with 50% torque to front axle and 50% to rear axle, then forward momentum is maintained, but side slip is difficult to induce
Solution Approach 1:
The system dynamically adjusts torque distribution between front and rear axles based on detected side slip conditions. When side slip is detected, the controller increases torque to the rear axle and decreases torque to the front axle, creating a dynamic torque bias that enhances side slip capability while maintaining forward momentum. This dynamic adjustment resolves the contradiction by allowing the vehicle to transition between stable forward motion and controlled side slip as needed.
2Ease of operation
If the vehicle operates in two wheel drive mode to enable side slip, then side slip is achieved, but forward momentum is difficult to maintain
Solution Approach 1:
The system applies different torque characteristics to different axles locally. The rear axle receives increased torque to enable side slip, while the front axle maintains sufficient torque to preserve forward momentum. This localized torque differentiation allows the vehicle to achieve side slip without completely disengaging forward drive capability, resolving the contradiction between side slip ease and forward momentum maintenance.
3Ease of operation
If torque distribution is adjusted to induce side slip, then side slip is achieved, but vehicle stability may be compromised
Solution Approach 1:
The system continuously monitors side slip conditions and uses this feedback to adjust torque distribution in real-time. When side slip is detected, the controller modifies torque allocation to enhance side slip; when excessive side slip or instability is detected, the controller reduces torque bias to restore stability. This closed-loop feedback control resolves the contradiction by dynamically balancing side slip capability with vehicle stability based on actual operating conditions.
Data Source
AI summary
Methods and systems for operating axles of a vehicle are provided. In one example, a propulsion source of a first axle is operated in a torque control mode at a first torque and a propulsion source of a second axle is operated in a torque control mode at a second torque. Torque of the propulsion sources may be adjusted as a function of steering angle.