Steering Control Gain Adjustment for Vehicle Stability
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Solution Overview
Problem
The existing electric power steering systems with redundant motor torque configurations experience variations in motor drive modes, leading to inconsistencies in vehicle behavior during steering, influenced by factors such as load changes and abnormal system conditions, which affect the conformity of turning angles with target angles.
Innovation Solution
A steering control device that adjusts the control gain based on factors like vehicle speed, acceleration, lateral acceleration, and temperature to optimize the angle control, utilizing multiple coil groups with independent and cooperative control modes to manage torque generation and reduce the likelihood of excessive motor torque, thereby improving steering behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant control systems are used to ensure continuous motor torque application, then reliability is improved, but plant characteristics vary depending on drive mode causing inconsistency in vehicle behavior
Solution Approach 1:
The patent dynamically adjusts control parameters (control gain, proportional gain, integral gain, differential gain) based on the current drive mode (cooperative mode, independent mode, or residual mode). This dynamic adaptation ensures that despite changes in system configuration, the overall control characteristics remain consistent, resolving the contradiction between maintaining reliability through redundancy and保持稳定 plant characteristics.
Solution Approach 2:
The patent changes control parameters according to the drive mode. Specifically, it adjusts the control gain, proportional gain, integral gain, and differential gain based on whether the system is in cooperative mode (both control systems normal), independent mode (one control system abnormal), or residual mode (one control system abnormal with different torque distribution). This parameter adaptation maintains consistent vehicle behavior across different operational states.
2Manufacturing precision
If control gain is increased to improve angle control precision, then manufacturing precision is improved, but vehicle behavior becomes overly sensitive to load changes and abnormal conditions
Solution Approach 1:
The control gain is not fixed but dynamically adjusted based on drive mode and operating conditions. In cooperative mode, a baseline control gain is used. In independent mode, the control gain is increased to compensate for the loss of one control system. In residual mode, the control gain is further adjusted based on torque distribution requirements. This dynamic adjustment maintains angle control precision while adapting to different operational conditions.
Solution Approach 2:
The patent implements parameter changes by adjusting control gain, proportional gain, integral gain, and differential gain based on the drive mode and operating conditions. This ensures that the angle control remains precise (improving manufacturing precision) while the system adapts to load changes and abnormal conditions (improving adaptability).
Data Source
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AI summary
A steering control device configured to control a steering device (2) includes a control unit. The control unit is configured to calculate a torque command value which is a target value of the motor torque based on execution of angle control for adjusting a convertible angle which is able to be converted to a rotation angle of the motor to a target angle; calculate the motor control signal based on the torque command value; and change a control gain which is used for the angle control based on a change of a factor influencing a behavior of a vehicle in response to steering.