Steering Force Detection with Inertial Correction
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Solution Overview
Problem
Existing steering operation force detection devices struggle to accurately detect the force applied to a steering wheel due to the interference of inertial forces, such as centrifugal force and gravitational force, which affect the measurement.
Innovation Solution
A device that includes input detection, steering angle detection, inertial force correction, gravitational force correction, and force applied point transformation to isolate and eliminate the effects of inertial and gravitational forces, allowing for precise detection of steering operation force by using load cells, sensors, and a control device to calculate and correct the detected forces in a coordinate system centered on the force applied point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the steering wheel rotates during operation, then the steering function is achieved, but inertial forces (centrifugal force and reverse rotation inertial force) act on the steering wheel rim, interfering with the detection of steering operation force
Solution Approach 1:
The patent detects inertial forces (centrifugal force and reverse rotation inertial force) that naturally occur during steering wheel rotation, and uses these detected inertial force components as correction values to eliminate their interference from the steering operation force measurement. By converting the harmful inertial forces into useful correction data, the system achieves accurate force detection despite the wheel's rotation.
Solution Approach 2:
The patent calculates and applies correction values for inertial forces before they interfere with the force detection. By deriving correction values based on steering angle changes and applying them in advance to compensate for inertial force effects, the system prevents interference rather than merely reacting to it.
2Measurement precision
If the steering wheel rim has empty weight, then the steering wheel structure is complete, but gravitational force acts on the steering wheel rim, interfering with the detection of steering operation force
Solution Approach 1:
The patent detects gravitational force components acting on the steering wheel rim due to its empty weight, and uses these detected gravitational force components as correction values to eliminate their interference from the steering operation force measurement. By converting the harmful gravitational interference into useful correction data, the system achieves accurate force detection.
3Measurement precision
If multiple correction systems are added to eliminate inertial and gravitational forces, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent uses a single force detection device that simultaneously detects multiple components including steering operation force, inertial forces (centrifugal and reverse rotation), and gravitational force. By making the detection device multi-functional, the system avoids needing separate detection systems for each force type, thereby reducing overall device complexity while maintaining high measurement precision through comprehensive correction capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively eliminates the impact of inertial and gravitational forces, enabling more accurate detection of steering operation force, thereby improving the precision of steering force measurement.
Implementation Method 1
inertial force that acts on an outer side in a radial direction of the rotating steering wheel (i.e. centrifugal force)
Implementation Method 2
inertial force acts on the rotating steering wheel
Implementation Method 3
gravitational force component acting on the steering wheel rim caused by an empty weight of the steering wheel rim
Data Source
AI summary
A steering operation force detection device for a steering wheel including a steering wheel rim having a right-side rim section and a left-side rim section. The device includes load cells that detect six component forces of the steering operation force acting on the right-side rim section and the left-side rim section consisting of forces in three axial directions and moments about three axes. The device includes a steering angle detection sensor that detects a steering angle of the steering wheel, and an inertial force component correcting unit that derives an inertial force component acting on the right-side rim section and the left-side rim section due to rotation of the steering wheel, based on an amount of displacement of the steering angle detected by the steering angle detection sensor, and that corrects the component force detected by the load cells to eliminate an effect of the derived inertial force component.