Electric Power Steering Torque Integral Mode Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric power steering systems face challenges in accurately switching from automatic to manual steering mode due to noise in torque sensors and inertia, leading to uncomfortable driver experiences and potential failure to stop automatic steering control when required.
Innovation Solution
An electric power steering apparatus that integrates steering torque and uses motor-state information (motor angular speed, acceleration, or centrifugal acceleration) to determine when to switch modes, eliminating the need for multiple threshold values and reducing calculation complexity by using a torque integral judging section to compare integrated values with predetermined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional threshold-based torque detection is used to switch from automatic to manual steering mode, then the system can detect driver input, but noise and inertia cause false detection leading to driver discomfort and unreliable mode switching
Solution Approach 1:
The system performs preliminary integration of torque values over time before making mode switching decisions. By accumulating torque data in advance and evaluating the integrated value against thresholds, the system filters out transient noise and inertia effects, enabling more reliable detection of genuine driver steering input while maintaining sensitive response to actual steering commands.
2Measurement precision
If multiple threshold values are used to improve mode switching accuracy, then detection precision improves, but system complexity and calculation load increase
Solution Approach 1:
The mode switching judgment is segmented into two independent threshold comparisons: one for detecting the start of manual steering mode (when integrated torque exceeds first threshold) and another for detecting return to automatic mode (when integrated torque falls below second threshold). This segmentation simplifies the control logic while maintaining accurate detection, avoiding the need for complex multi-threshold evaluation systems.
3Speed
If the system responds immediately to torque threshold exceedance, then switching speed is fast, but noise causes premature switching and driver discomfort
Solution Approach 1:
The system performs preliminary integration of torque values over time before making mode switching decisions. By accumulating torque data in advance and evaluating the integrated value against thresholds, the system filters out transient noise and inertia effects, enabling more reliable detection of genuine driver steering input while maintaining sensitive response to actual steering commands.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
[Problem] An object of the present invention is to provide an electric power steering apparatus that detects that a driver steers the handle by using a steering torque from the torque sensor, switches to the manual steering mode due to a capacity (an integrated value) corresponding to a generated torque, and does not give an uncomfortable feeling to the driver [Means for solving the problem] An electric power steering apparatus comprises a steering angle control section to calculates a motor current command value 2, a torque integral judging section to output a steering torque judging signal by integrating the steering torque and comparing with a threshold, and a switching section that inputs the motor current command values 1 and 2 and is switched by a switching signal or the steering torque judging signal, wherein the torque integral judging section comprises a torque value comparing section, a torque-sensitive or a motor-state information-sensitive type gain section, an integral calculating section and a switch judging section, wherein the switching section is switched in correspondence with a switching command of the automatic steering mode and the manual steering mode, or the steering torque judging signal.