Autonomous Steering Control Mode Switching for Consistent Steering Feel
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Solution Overview
Problem
Existing autonomous driving systems do not account for the change rate of steering torque, leading to inconsistent steering feel based on vehicle speed, causing discomfort for the driver.
Innovation Solution
An autonomous driving control device that switches between control modes based on the driver's steering operation, adjusting the steering force and reaction force to match the speed of steering wheel manipulation, using a detection unit to determine the appropriate timing for mode change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the target steering torque is reduced at a uniformly determined change rate, then the control is simplified, but the steering torque becomes too small when the steering wheel is turned at low speed and too large when turned at high speed, causing driver discomfort
Solution Approach 1:
The patent applies dynamics by making the change rate of target steering torque variable rather than fixed. The control device dynamically adjusts the reduction rate based on the actual steering speed detected during driver operation, ensuring the steering torque changes appropriately whether the wheel is turned slowly or quickly, thereby resolving the contradiction between simplified control and comfortable operation.
Solution Approach 2:
The patent changes the parameter of target steering torque reduction rate based on steering speed. By detecting the actual steering speed and adjusting the reduction rate accordingly, the system maintains appropriate steering torque characteristics across different operating conditions, solving the problem of uniform reduction rate causing discomfort.
2Speed
If the target steering torque is reduced rapidly, then the response to driver input is faster, but the steering torque changes too abruptly causing sudden shifts in steering feel and driver discomfort
Solution Approach 1:
The system dynamically adjusts the torque reduction process based on actual steering speed. When steering speed is high, the reduction rate is increased for faster response; when steering speed is low, the reduction rate is decreased to maintain smooth steering feel. This dynamic adjustment resolves the contradiction between rapid response and stable steering characteristics.
Solution Approach 2:
The control device uses feedback from the detection unit that monitors actual steering speed and operation amount. This feedback loop allows the system to adjust the target steering torque reduction rate in real-time based on actual driver input characteristics, ensuring both rapid response and consistent steering feel throughout the transition.
3Stability of the object's composition
If the steering torque is maintained at high levels, then the steering control is more stable during autonomous driving, but the driver experiences difficulty when needing to operate the steering wheel
Solution Approach 1:
The system dynamically transitions from a high-stability autonomous driving mode to a driver-assisted mode based on detected steering operation. When the detection unit identifies driver input, the control device begins reducing the target steering torque at an adjusted rate, allowing the system to maintain stability during autonomous operation while becoming more responsive and easier to operate when the driver intervenes.
Data Source
AI summary
An autonomous driving control device includes a steering determination unit that determines whether a driver has operated a steering unit while driving with an actuator controlled in a first control mode, an operation speed calculation unit that calculates at least one of a deviation speed, which is the change rate of deviation between a target steering angle during autonomous driving and an actual steering angle, and a steering speed, which is the change rate of the actual steering angle, and a control mode switching unit that, when it is determined that the driver has operated the steering unit, changes an instruction value to be output to the actuator from a first target control amount in the first control mode to a second target control amount in the second control mode at a change rate corresponding to at least one of the deviation speed and the steering speed described above.