Tie Rod Force Estimation for Steer-By-Wire Systems by Means of Intelligent Model Transition

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This invention provides a method for estimating the force in the tie rod of a vehicle's steer-by-wire system using an intelligent combination of two different physical models. The method uses measured sensor data from the vehicle to evaluate two separate models, one optimized for very low speeds (including standstill) and another for higher speeds. The lateral forces calculated by these models are converted into tie rod forces and then combined through a weighted strategy that adapts according to vehicle speed or operating conditions. The resulting force estimate can then be refined for smoother integration into vehicle control systems, particularly for feeding force-feedback in electronic steering systems without a direct mechanical link.

Use CasesContent extracted from patent full text and abstract with AI.

• Steer-by-wire automotive steering systems requiring precise estimation of tie rod forces for safe operation and realistic driver feedback.
• Electronic power steering development, where physical sensors for tie rod forces are impractical or costly.
• Autonomous vehicle platforms that need accurate, model-based steering force calculation for motion control.
• Retrofit or upgrade kits for existing vehicles converting to steer-by-wire systems, providing advanced software-based force estimation.
• Testing and simulation environments where virtual models replace physical hardware for cost-effective development and validation.

BenefitsContent extracted from patent full text and abstract with AI.

• Enables accurate estimation of tie rod forces without the need for dedicated physical sensors, reducing hardware cost and potential points of failure.
• Provides a seamless transition between different physical models, ensuring accurate force estimation across the full range of vehicle speeds and maneuvers.
• Improves safety and the natural feel of steering feedback for drivers in steer-by-wire vehicles, enhancing driver confidence and comfort.
• Enhances software explainability and adaptability due to transparent model-blending approaches, which is valuable for safety-critical automotive systems.
• Facilitates integration with advanced driver-assistance and autonomous vehicle systems by enabling robust and sensor-efficient force feedback calculation.

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Patent Abstract

The invention relates to a method for estimating a tie rod force of a steering device of a vehicle, comprising the following method steps: (a) two models (1, 2) are first evaluated using measured values and/or sensor signals from the vehicle in order to obtain a first and a second lateral force, respectively; (b) the first and second lateral forces are converted into a first and a second tie rod force, respectively, using parameters of the steering geometry (3); (c) the first and second tie rod forces are combined with each other in order to obtain a third tie rod force, the third tie rod force being a weighted combination of the first and second tie rod forces.