Vehicle Wheel Lock Detection and Targeted Freeing Control
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Solution Overview
Problem
Locked wheels in vehicles can prevent movement and cause undesirable yaw moments due to frozen or corroded brake components, and existing systems lack a reliable method to detect and free such wheels, especially in autonomous or partially autonomous vehicles.
Innovation Solution
A method that identifies locked wheels through various sensors and vehicle models, selects a suitable wheel freeing strategy, and applies it to free the wheel, including increasing torque, alternating torque, or dragging the wheel, while considering the vehicle's environment and obstacles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locked wheel is not detected and freed, then the vehicle cannot move or reacts unexpectedly to steering/torque requests, but implementing a detection and freeing system increases device complexity
Solution Approach 1:
The system segments the wheel detection problem by individually monitoring each wheel's rotational status through wheel speed sensors. The control unit evaluates each wheel separately to identify locked conditions, allowing targeted freeing strategies for specific locked wheels rather than treating all wheels uniformly. This segmentation enables precise intervention while maintaining overall system reliability.
Solution Approach 2:
The system performs preliminary detection of locked wheels by continuously monitoring wheel speeds and comparing them against vehicle motion status. Before the locked wheel prevents vehicle movement or causes unsafe conditions, the control unit identifies the locked state and automatically initiates freeing strategies such as applying propulsion torque or releasing brake pressure, preventing the harmful effects of undetected locked wheels.
2Reliability
If generic freeing strategies are applied to all wheels without identification, then the system is simpler to implement, but the chances of success are reduced
Solution Approach 1:
The system applies local quality by tailoring the freeing strategy to the specific locked wheel identified. Different wheels may receive different treatments based on their individual locked conditions, vehicle motion state, and which propulsion actuators are available. For example, if wheel A is locked and the vehicle is stationary, the system applies torque to wheel A; if wheel B is locked during motion, the system may use drag forces from other wheels. This localized approach maximizes freeing success rates.
Solution Approach 2:
The system dynamically adapts the freeing strategy based on real-time vehicle conditions. The control unit continuously evaluates the locking scenario, considering factors such as whether the vehicle is moving, which wheels are locked, and available propulsion actuators. The freeing strategy changes dynamically - using propulsion torque when stationary, drag forces when moving, or alternating torque patterns - optimizing the chance of success for each specific situation rather than applying a static generic approach.
3Productivity
If multiple freeing strategies are implemented for different locking scenarios, then the effectiveness of freeing locked wheels is enhanced, but the control logic and system complexity increase
Solution Approach 1:
The control unit dynamically selects and switches between multiple freeing strategies based on the identified locking scenario. When a locked wheel is detected, the system evaluates current vehicle conditions (motion state, available actuators) and automatically applies the most appropriate strategy: propulsion torque for stationary vehicles, drag forces from free wheels for moving vehicles, or alternating torque patterns. This dynamic adaptation achieves high freeing effectiveness without requiring manual intervention for each scenario.
Solution Approach 2:
The system provides self-service by automatically detecting locked wheels, evaluating the locking scenario, selecting appropriate freeing strategies, and executing the freeing action without external intervention. The control unit monitors wheel speeds, identifies locked conditions, and autonomously applies the necessary torque or brake pressure adjustments. This self-service capability handles multiple locking scenarios effectively while keeping the control logic centralized and automated, reducing the need for complex manual control procedures.
Data Source
Figure 1~2
AI summary
The disclosure relates to a method for freeing at least one locked wheel (12) of a vehicle (10). One step of the method relates to identifying a locking scenario comprising the identification of the at least one locked wheel (12). A further method step is selecting a wheel freeing strategy being suitable for the identified locking scenario. Another step is directed to applying the selected wheel freeing strategy. Furthermore, the disclosure is directed to a propulsion system (14) for a vehicle (10) having at least one wheel (12). The propulsion system (14) comprises at least one propulsion actuator (16). Moreover, at least one wheel speed sensor (18) is provided, the wheel speed sensor (18) being configured for detecting the rotational speed of the at least one wheel (12). Additionally, the propulsion system (14) has at least one brake unit (20) being configured for braking the at least one wheel (12) and a control unit (28) being configured for performing the above method.