Rear Wheel Toe Angle Controller Actuator Feedback
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Solution Overview
Problem
Existing toe angle controllers for vehicle rear wheels may fail to set target toe angles due to insufficient actuator output, leading to deteriorated vehicle motion performance.
Innovation Solution
A toe angle controller system that includes actuators, a control unit, toe angle detection units, and correction units, which corrects target toe angles based on differences between calculated and actual toe angles, using lateral acceleration to enhance the setting of toe angles for both rear wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an actuator with large thrust force is used to compensate for insufficient output, then the turning amount of the rear wheel is improved, but the weight, size, and cost increase
Solution Approach 1:
The system uses feedback control by detecting the actual toe angle with a detection unit, comparing it with the target toe angle calculated by the control unit, and adjusting the actuator output accordingly. This closed-loop feedback mechanism ensures the rear wheel achieves the correct turning amount without requiring an oversized actuator, thus avoiding increased weight while maintaining operational effectiveness.
Solution Approach 2:
The control unit dynamically adjusts the actuator's output parameters (torque, speed) based on the difference between target and actual toe angles, vehicle speed, and steering angle. By optimizing these parameters in real-time, the system achieves sufficient turning performance without requiring an actuator with excessively large thrust force, thereby preventing weight increase.
2Manufacturing precision
If the actuator output is insufficient, then the target toe angle cannot be set accurately, but increasing actuator size increases cost and complexity
Solution Approach 1:
The toe angle detection unit provides real-time feedback on the actual toe angle, which is compared with the target toe angle by the control unit. This feedback loop enables precise correction of any deviation, ensuring accurate toe angle setting without requiring an overly complex or oversized actuator system.
Solution Approach 2:
The system replaces reliance on purely mechanical actuator strength with an electronic control system that uses sensors, signal processing, and algorithmic control to achieve precise toe angle positioning. This substitution of mechanical brute force with electronic intelligence reduces both actuator size and overall system complexity while maintaining or improving precision.
3Reliability
If one rear wheel's toe angle cannot be set to target value, then vehicle motion performance deteriorates, but using larger actuators on both wheels increases weight and cost
Solution Approach 1:
The independent feedback control for each rear wheel detects when the actual toe angle deviates from the target value and automatically adjusts the actuator output to correct the deviation. This ensures reliable vehicle motion performance is maintained even under varying conditions, without requiring heavier actuators on both wheels.
Solution Approach 2:
The control system applies localized correction to each rear wheel independently based on its specific conditions (actual vs. target toe angle). This localized quality control ensures that each wheel receives the precise amount of correction needed, maintaining overall vehicle performance without unnecessarily increasing the capacity and weight of both actuators.
Data Source
AI summary
It is possible to drive a motor (7) with a high output during a low-speed travel and perform steering with a high resolution during a high-speed travel. An electric power steering device (1) causes the motor (7) to generate an auxiliary torque based on the steering torque specified by a driver for operating steering wheels (9), thereby reducing the steering torque specified by the driver. A control device (10) uses the vehicle speed signal (Vs) from a vehicle speed sensor (11) so as to drive the motor (7) with a high output during a low-speed travel and perform steering with a high resolution during a high-speed travel without increasing the motor output. Moreover, during a low-speed travel, a large steering torque is required and during a high-speed travel, steering should be performed with a high resolution. Thus, the driver's feeling in steering is not affected.