In-wheel Motor Resolver for Rough Road Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle state detection systems require a large number of sensors to detect external forces, leading to increased costs, weight, and installation space requirements.
Innovation Solution
A vehicle state detection device that utilizes a rotational angle sensor, including a magnetism detection signal output part and a rotational angle calculation part, to detect variations in the magnetism detection signal or calculated rotational angle not caused by changes in the motor's rotational angle, allowing for the acquisition of external force indices without additional dedicated sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated sensors for detecting forces acting on the vehicle are mounted, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The rotational angle sensor originally designed for detecting motor rotor position is made to serve dual purposes: its primary function of detecting rotational angle and a secondary function of detecting external forces acting on the vehicle. By analyzing variations in the magnetism detection signal that cannot be explained by rotor position changes, the system extracts force information from an existing sensor without adding dedicated force sensors.
Solution Approach 2:
The rotational angle sensor performs self-service by providing both rotational angle data for motor control and external force data for vehicle state detection. The sensor's inherent magnetism detection capability is utilized to detect force-induced variations in the magnetic field, allowing the sensor to contribute to multiple detection functions simultaneously.
2Measurement precision
If multiple sensors are installed to detect vehicle state, then measurement precision is improved, but weight increases
Solution Approach 1:
The rotational angle sensor is designed to perform multiple detection functions simultaneously. By analyzing the magnetism detection signal variations that cannot be attributed to rotor position changes, the system extracts external force information from the same sensor used for rotational angle detection, thereby avoiding the need for additional dedicated force sensors and reducing overall system weight.
3Measurement precision
If dedicated force detection sensors are added, then measurement precision is improved, but installation space requirements increase
Solution Approach 1:
The rotational angle sensor's magnetic detection mechanism is utilized for dual purposes: detecting rotor position for motor control and detecting external forces through signal variation analysis. This multi-functional approach eliminates the need for separate force detection sensors and their associated installation space.
Solution Approach 2:
The force detection function is merged with the existing rotational angle detection function within the same sensor unit. By combining both detection capabilities in a single sensor system, the patent avoids the need for separate force sensors and reduces the total installation space required for sensing components.
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
Enables the detection of external forces acting on a vehicle using existing motor sensors, reducing the need for additional sensors and minimizing costs, weight, and installation space while providing accurate force magnitude and direction information.
Implementation Method 1
a magnetism detection signal output part including a rotor (42) to be rotated by a rotation of the motor, and a stator (43) arranged around the rotor, the magnetism detection signal output part being configured to output a magnetism detection signal changing in response to a relative positional relationship between the rotor and the stator
Data Source
AI summary
An unsprung state detection part (140) calculates a variation amount X (=|φ−φ′|), which is a magnitude of a difference between a detected angle φ output from a resolver rotational angle sensor (40) for detecting a rotational angle of an in-wheel motor (30) and an estimated angle φ′ of a motor rotational angle (S11 to S13). The estimated angle φ′ can be calculated by adding an estimated angle of the rotation of the motor (30) in one calculation cycle to a detected angle φn−1 of the previous calculation cycle. When the variation amount X is more than a road surface determination threshold Xref, the unsprung state detection part (140) determines that the travel road on which a vehicle (1) is traveling is a rough road (S14, S15). As a result, the road surface determination can be made by using the rotational angle sensor (40).