Tire Normal Force Estimation via Suspension Sensors
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Solution Overview
Problem
Existing methods for determining tire normal forces rely on tire or wheel sensors, which are not always available or necessary, and require tire or road information, limiting their applicability in various devices like vehicles and robots.
Innovation Solution
A device with a suspension system and a controller that uses suspension sensors to determine real-time tire normal forces without requiring tire sensors, by calculating a transformation matrix based on predefined parameters such as distances, moment of inertia, and tire masses, allowing for the estimation of tire normal forces using suspension data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tire sensors are used to determine tire normal forces, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses suspension sensors as an intermediary component to indirectly measure tire normal forces. Instead of placing sensors directly on the tires, the invention measures suspension system parameters (forces, displacements, accelerations) and uses these as intermediate data to calculate tire normal forces through mathematical models and transformation matrices, thereby avoiding direct tire sensor installation
Solution Approach 2:
The patent replaces the mechanical sensor system (tire-mounted force sensors) with a computational approach using suspension system dynamics. The mechanical measurement problem is substituted by using equations of motion, transformation matrices, and parameter estimation algorithms that compute tire normal forces from suspension system behavior without direct mechanical contact with tires
2Measurement precision
If tire or road information is required for determination, then measurement precision is improved, but adaptability deteriorates
Solution Approach 1:
The patent creates a universal measurement system that works across different device types (vehicles, robots, farm implements) without requiring device-specific calibration or tire information. The suspension system dynamics approach is universally applicable to any device with a suspension system, making the solution multi-functional and highly adaptable to various applications
Solution Approach 2:
The patent transforms the measurement approach by changing from direct tire parameter measurement (requiring tire-specific information) to suspension system parameter measurement (forces, displacements, accelerations). This parameter transformation enables the system to determine tire normal forces without needing to know tire characteristics, road conditions, or device-specific parameters
Data Source
AI summary
A device includes a plurality of tires and a suspension system as subcomponents. The suspension system includes at least one suspension sensor configured to provide suspension data (S). A controller is operatively connected to the suspension sensor. The controller has a processor and tangible, non-transitory memory on which is recorded instructions for executing a method for determining respective tire normal forces (Fzi(t), i=1 . . . 4) for one or more of the plurality of tires, based at least partially on the suspension data (S). The tire normal force (Fz) is the net force acting on each tire (or wheel) in the vertical direction. The tire normal force acting on each tire may be determined without using the specific model of the tire, road information, wheel or tire sensors.