Steering Motor Control with Dead-Zone Alert Vibration Logic
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Solution Overview
Problem
Existing motor control devices fail to effectively apply alert vibration to a steering wheel based on vehicle driving conditions, particularly when integrating manual and automatic steering command values.
Innovation Solution
A motor control device that includes an assist torque command value setting unit, a manual steering command value calculation unit, an integrated angle command value calculation unit, a dead zone processing unit, and an alert vibration application unit, which uses road information to calculate manual steering command values when specific conditions are met, applying alert vibration torque as a component of the motor torque command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor control device integrates manual and automatic steering command values for angle control, then the steering control precision is improved, but the device complexity increases due to multiple calculation units and control pathways
Solution Approach 1:
The control system is segmented into distinct functional units: assist torque command value setting unit, manual steering command value calculation unit, integrated angle command value calculation unit, dead zone processing unit, and alert vibration application unit. Each unit handles a specific aspect of the control task, making the complex system manageable and maintainable while achieving precise integrated steering control
Solution Approach 2:
The motor control device integrates multiple functions into a single control system that can perform both manual steering control and automatic steering control, and additionally applies alert vibration to the steering wheel. The integrated angle command value calculation unit combines inputs from both manual and automatic steering systems, achieving multi-functional operation
2Ease of operation
If the dead zone processing unit is provided for input torques, then the ease of operation is improved by filtering out minor fluctuations, but the response time worsens when the steering torque is within the dead zone range
Solution Approach 1:
The dead zone processing unit dynamically adjusts the threshold for processing steering torque inputs. When alert vibration is being applied, the system determines whether to apply dead zone processing based on current operating conditions, making the dead zone range variable rather than fixed. This allows the system to maintain operational smoothness under normal conditions while improving response time when alert vibration is active
3Adaptability or versatility
If the manual steering command value calculation unit uses road information to calculate manual steering command value, then the adaptability is improved for different road conditions, but the device complexity increases due to additional information processing requirements
Solution Approach 1:
The system prestores a map that stores the relationship between steering torque and the peak value of vibration torque. This preliminary preparation allows the system to quickly access and apply appropriate vibration parameters based on current steering conditions, avoiding complex real-time calculations while adapting to different road conditions
Solution Approach 2:
The manual steering command value calculation unit acts as an intermediary that processes road information and integrates it with steering torque inputs. This intermediate processing layer adapts the raw road information into useful control commands, making the system adaptable to different road conditions while managing information processing complexity
4Reliability
If alert vibration torque is applied to the steering wheel, then the driver awareness is improved for safety alerts, but the manufacturing precision worsens due to increased mechanical stress and vibration on the steering system
Solution Approach 1:
The alert vibration application unit applies vibration torque in a periodic manner rather than continuously. The vibration is activated only when specific conditions are met (when the first condition is satisfied), and the system can suspend or reduce vibration when conditions change. This periodic application provides effective safety alerts while minimizing cumulative mechanical stress on the steering system
Solution Approach 2:
The system changes the parameter of vibration torque based on steering torque conditions. The vibration torque calculation unit sets the value of the vibration torque so that the value of the vibration torque increases as the steering torque increases and the value of the vibration torque decreases as the steering torque decreases. This adaptive parameter adjustment ensures effective alert vibration while reducing mechanical stress under high steering torque conditions
Data Source
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.