Steering Motor Control With Dead-Zone Torque and Alert Vibration
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Solution Overview
Problem
Existing motor control devices for electric motors in steering systems do not effectively apply alert vibrations to the steering wheel based on vehicle driving conditions, and lack the ability to integrate manual and automatic steering command values efficiently.
Innovation Solution
A motor control device that calculates an integrated angle command value by combining manual and automatic steering command values, incorporates a dead zone processing unit to handle input torques, and applies alert vibrations using road information when specific conditions are met, ensuring the alert vibration is applied based on driving conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alert vibration torque is applied to the steering wheel based on driving conditions, then driver alertness and safety are improved, but steering control precision and comfort deteriorate due to unwanted vibrations during normal operation
Solution Approach 1:
The system changes the parameter of steering torque by superimposing vibration torque only under specific driving conditions (when lane deviation is detected), rather than maintaining a constant state. This allows the steering system to transition between normal precision control and alertness-inducing vibration modes based on operational context.
Solution Approach 2:
The dead zone range is made dynamic rather than fixed - it varies based on steering torque magnitude and driving conditions. During alert vibration application, the dead zone adjusts to prevent unnecessary vibrations while allowing intentional vibrations for driver alertness, creating a adaptive control system that responds to real-time operational states.
2Stability of the object's composition
If dead zone processing is applied to steering torque input, then control stability is improved by filtering out small fluctuations, but responsiveness to actual steering inputs deteriorates due to delayed response within the dead zone range
Solution Approach 1:
The dead zone range is dynamically adjusted based on steering torque magnitude and driving conditions. When steering torque exceeds certain thresholds or during specific alert conditions, the dead zone range changes to balance filtering of noise versus responsiveness to genuine steering inputs, preventing fixed dead zones from causing consistent response delays.
Solution Approach 2:
Different dead zone ranges are applied to different regions of steering torque operation. Small steering torques within the dead zone receive filtering treatment for stability, while larger torques or torques during alert conditions bypass the dead zone for immediate response, creating localized control characteristics throughout the operating range.
3Measurement precision
If road information is used to calculate manual steering command value, then steering accuracy is improved by compensating for road reaction torque, but system complexity increases due to additional sensors and processing requirements
Solution Approach 1:
The steering torque sensor serves multiple functions: it detects both driver steering inputs and road reaction torque. By processing the same sensor data through different calculation paths (with or without road information compensation), the system achieves high steering accuracy without adding dedicated sensors for road torque measurement, thereby avoiding increased hardware complexity.
Data Source
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AI summary
A manual steering command value calculation unit is configured to use road information including information on a road reaction torque to calculate a manual steering command value when a first condition that at least one of input torques for which a dead zone processing unit is provided is outside a dead zone range is satisfied, and not to use the road information to calculate the manual steering command value when the first condition is not satisfied. When alert vibration torque is being applied, the manual steering command value calculation unit uses the road information to calculate the manual steering command value for a predetermined period from a time when a state in which the first condition is satisfied changes to a state in which the first condition is not satisfied.