Turning Control Assist Torque Regulation for Universal Joint Torque Variation
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Solution Overview
Problem
The variation in torque at the position closer to the turning wheel due to the universal joint in existing steering systems causes a strange feeling for the driver and interferes with intended vehicle behavior control.
Innovation Solution
A turning control device that includes a processor to manage the assist motor torque based on steering angle, restricting torque variation using a priority-based control process to maintain a balance between steering feel and vehicle controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the assist motor torque is varied depending on the steering angle to compensate for universal joint torque variation, then the steering torque variation is reduced, but the vehicle behavior control accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the assist motor torque based on steering angle to compensate for universal joint torque variation. The control device varies the assist torque parameter in response to steering angle changes, which reduces steering torque variation and improves steering feel while maintaining vehicle behavior control accuracy through priority-based control logic.
2Stability of the object's composition
If the torque at the position closer to the turning wheel is controlled to not vary depending on steering angle, then the steering torque is stabilized, but the torque given to the steering shaft varies depending on steering angle causing driver discomfort
Solution Approach 1:
The patent uses parameter changes by varying the assist motor torque parameter according to steering angle. This dynamic adjustment ensures that the torque given to the steering shaft remains stable despite universal joint effects, while the controlled variation in assist torque compensates for steering torque fluctuations, thereby maintaining both steering torque stability and driver comfort.
3Ease of operation
If the assist motor torque is adjusted to compensate for universal joint effects, then steering torque variation is reduced, but the complexity of the control system increases
Solution Approach 1:
The patent implements feedback control by using a steering angle sensor to detect the steering angle and then adjusting the assist motor torque accordingly. The control device receives feedback from the steering angle sensor and dynamically modifies the assist torque to compensate for universal joint torque variation, thereby improving steering feel without requiring complex mechanical modifications.
4Measurement precision
If the priority degree of control torque variable is considered in torque variation restriction, then vehicle behavior control accuracy is maintained, but the control process complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the priority degree parameter based on driving conditions. The control device changes the priority degree parameter to balance between steering feel improvement and vehicle behavior control accuracy, allowing flexible control without requiring complex control logic by simply adjusting this key parameter.
Data Source
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AI summary
A processor (52) included in a turning control device (50) is configured to execute a manipulation process of manipulating a drive circuit of an assist motor (42) depending on a torque that depends on at least one of the two values, the value of an assist torque variable and the value of a control torque variable. The processor (52) is configured to execute a variation torque control process of varying a torque as an input variable in the manipulation process, depending on a steering angle, based on the value of the steering angle variable as an input variable. The processor (52) is configured to execute a restriction process of restricting the magnitude of variation in the torque as the input variable in the manipulation process depending on the steering angle, to a small side, depending on the priority degree of the value of the control torque variable in the manipulation process.