Steering Angle Sensor With Slotted Magnet Encoder
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Solution Overview
Problem
Existing vehicle systems face challenges in accurately measuring the steering angle of the steering column, leading to potential loss of wheel contact with the road and deviation from the intended trajectory, which existing vehicle dynamic control systems struggle to correct effectively.
Innovation Solution
A vehicle equipped with a steering angle sensor that includes an encoder with a circular first magnet and a second magnet, where the magnets are orthogonal to the rotation axis and displaced in the rotation direction, and a magnet sensor positioned axially displaced from the encoder, with specific geometric configurations such as a through hole or slot, to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional encoder without a slot is used, then the structure is simpler, but the measurement precision of the steering angle is reduced
Solution Approach 1:
The encoder is segmented by introducing a slot that divides the magnetic field into distinct regions. This segmentation allows the magnet sensor to detect different magnetic field characteristics on either side of the slot, thereby improving the precision of steering angle measurement while adding only a simple structural element.
Solution Approach 2:
The slot acts as an intermediary element that modifies the magnetic field distribution between the encoder magnet and the magnet sensor. By introducing this intermediate structure, the magnetic field lines are redirected and concentrated in specific areas, enhancing the sensor's ability to detect precise angular positions.
2Measurement precision
If the magnet sensor is placed closer to the encoder, then the measurement sensitivity increases, but the magnetic field interference from the slot increases
Solution Approach 1:
The slot is designed with specific local characteristics - its position, width, and depth are optimized to create a controlled magnetic field disturbance only in the immediate vicinity of the slot, while maintaining stable magnetic field conditions in the regions where the magnet sensor operates. This localized modification allows close sensor placement without excessive interference.
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 solution provides improved accuracy in measuring the steering angle, enabling better vehicle dynamic control and preventing wheel deviation by ensuring precise steering angle detection and correction, thereby enhancing driving stability and control.
Implementation Method 1
a steering angle sensor for measuring a rotation angle of the steering column around a rotation axis with an encoder that is stationary to the steering column, and with a magnet sensor that is disposed axially displaced from the encoder on the rotation axis
Data Source
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AI summary
The invention relates to a vehicle (2) comprising - a chassis (4) that is moveable in a driving direction (3), - two rear wheels (6) moveably carrying the chassis (4) on the rear side seen in the driving direction (3), - two front wheels (6) moveably carrying the chassis (4) on the front side seen in the driving direction (3), - a steering wheel (7) for turning a steering column (26) around a rotation axis (28) for steering the front wheels (5), and - a steering angle sensor (32) for measuring a rotation angle (8) of the steering column (26) around the rotation axis (28) with an encoder (34) that is stationary to the steering column (26) and with a magnet sensor (36) that is disposed axially displaced (72) from the encoder (34) on the rotation axis (28), characterized in that the encoder (34) includes a first magnet (38) with a top side (48) directed to the magnet sensor (36) and a second magnet (40) attached to the first magnet (38) opposite to the top side (48), wherein the first magnet (38) includes a recess starting (50) from the top side (48) and extending at least until the second magnet (40), wherein each magnet (38, 40) is magnetized orthogonal to the rotation axis (28), and wherein regarding from the magnetizations (42, 44), the first magnet (38) and the second magnet (40) are displaced against each other in rotation direction (46).