Power Steering Abnormality Detection Circuit
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Solution Overview
Problem
Existing power steering apparatuses lack accurate abnormality detection, particularly in regions where steering direction changes, leading to potential operational failures due to factors like water ingress and rust development.
Innovation Solution
Incorporating an abnormality detection circuit that monitors changes in steering torque within a predetermined region where the steering direction signal is switched, allowing for early detection of operational anomalies, such as stuck steering, without requiring specialized foreign object detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If abnormality detection is performed in conventional power steering apparatuses, then operational failures may occur due to inaccurate detection, but the system lacks the capability to detect abnormalities at early stages
Solution Approach 1:
The abnormality detection circuit performs detection in advance during normal steering operations before failures occur. By continuously monitoring steering torque in predetermined regions including switching regions, the system detects abnormalities at early stages rather than waiting for operational failures, thus improving both detection accuracy and reliability
Solution Approach 2:
The detection circuit uses feedback from steering torque sensor signals to continuously monitor for abnormalities. By comparing actual steering torque with expected values in predetermined regions, the system provides continuous feedback to detect deviations indicating abnormalities, enhancing detection precision while maintaining operational reliability
2Reliability
If specialized foreign object detection functions are added to detect water ingress and rust, then detection capability improves, but device complexity and cost increase
Solution Approach 1:
The abnormality detection circuit serves multiple functions by monitoring steering torque characteristics in predetermined regions. It detects various abnormalities including water ingress, rust, and mechanical failures through a single unified detection mechanism, eliminating the need for separate specialized sensors and reducing system complexity while maintaining comprehensive detection capability
Solution Approach 2:
The existing steering torque sensor and control unit are utilized for abnormality detection without requiring additional specialized foreign object detection equipment. The system uses its own operational data to self-diagnose abnormalities, simplifying the overall system architecture while maintaining reliable detection of water ingress, rust, and other mechanical issues
Data Source
AI summary
One of objects of the present invention is to provide a power steering apparatus capable of improving accuracy of abnormality detection. A power steering apparatus includes a steering mechanism configured to transmit a rotation of a steering wheel to a turning target wheel, an electric motor configured to provide a steering force to the steering mechanism, a torque sensor configured to detect a steering torque generated on the steering mechanism, and a control unit configured to calculate, based on the steering torque, an instruction signal for controlling driving of the electric motor and output the instruction signal to the electric motor. The control unit includes a steering direction signal reception portion configured to receive a steering direction signal indicating a rotational direction of the steering wheel, and an abnormality detection circuit configured to carry out detection of an abnormality in the power steering apparatus based on a change in the steering torque in a predetermined region including a region in which the steering direction signal is switched.