Parking Wheel Control With Dual-Loop Feedback for Fast Precision
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Solution Overview
Problem
Existing parking control systems suffer from long delays and poor precision, especially in the presence of road surface disturbances, leading to issues like oversteering, vehicle pitching, and excessive gear changes during automatic and manual parking.
Innovation Solution
A closed-loop control system with a short control path through a motor control unit, motor, and motor sensor, utilizing high-precision motor rotation information to quickly adjust wheel rotation and correct drive signals, enhancing precision and reducing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a traditional parking control system is used with a long control path through main control unit, motor control unit, motor, and wheel sensor, then the system structure is simple and easy to implement, but the control delay is long and response speed is slow
Solution Approach 1:
The control system is segmented into two independent control loops: a speed control loop handled by the motor control unit and a position control loop handled by the main control unit. This segmentation allows the speed loop to operate with high frequency for fast response while the position loop operates at lower frequency for strategic control, resolving the contradiction between response speed and system complexity.
Solution Approach 2:
The motor control unit acts as an intermediary between the main control unit and the motor. It receives both position commands from the main control unit and feedback from the motor sensor, then performs local closed-loop speed control. This intermediary structure shortens the control path for speed control while maintaining the overall system architecture.
2Manufacturing precision
If the control path is shortened to improve response speed, then control delay is reduced and parking precision is improved, but the system requires more sophisticated coordination between control units
Solution Approach 1:
A dual feedback mechanism is implemented: the motor sensor provides real-time speed feedback to the motor control unit for closed-loop speed control, and the wheel sensor provides position feedback to the main control unit for closed-loop position control. This multi-level feedback system enables high precision parking while distributing control complexity across different control units.
Solution Approach 2:
The motor control unit performs preliminary speed adjustment based on motor rotation information before the main control unit executes position correction. This preliminary action reduces the burden on the main control unit and enables faster overall response, improving precision without proportionally increasing coordination complexity.
3Reliability
If high-frequency closed-loop control is implemented on the motor control unit side, then control delay is reduced and road surface disturbances are quickly corrected, but the control algorithm complexity increases
Solution Approach 1:
The control system dynamically adjusts the frequency and complexity of control operations: the motor control unit executes high-frequency speed control for disturbance rejection, while the main control unit executes lower-frequency position control. This dynamic allocation of control tasks improves reliability without requiring maximum complexity throughout the entire system.
Solution Approach 2:
The motor control unit performs partial closed-loop control for speed regulation, handling the time-critical disturbance rejection function. The main control unit then performs the remaining position correction. This partial action approach achieves reliable disturbance rejection without implementing full high-frequency control across all control functions.
4Manufacturing precision
If motor rotation information is used for drive signal correction, then parking control precision is improved and gear changes are reduced, but the data processing requirements increase
Solution Approach 1:
The motor control unit performs preliminary conversion of motor rotation information into wheel rotation information and executes initial drive signal correction before the main control unit processes position data. This preliminary action reduces the data processing burden on the main control unit and enables high precision control without significant time loss.
Solution Approach 2:
The time-critical task of drive signal correction based on motor rotation information is extracted from the main control unit and assigned to the motor control unit. This extraction allows the correction to be performed with minimal delay using locally available data, improving precision without burdening the main control unit's processing timeline.
Data Source
AI summary
A parking control system comprises a main control unit that sends target wheel rotation information to a motor control unit of a vehicle during parking of the vehicle. The motor control unit determines a drive electrical signal corresponding to the target wheel rotation information, sends the drive electrical signal to a motor of the vehicle, and corrects a subsequent drive electrical signal based on motor rotation information collected by a motor sensor of the vehicle.