Electronic Braking System Software Loop Synchronization
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Solution Overview
Problem
In combined brake systems with hydraulically and electromechanically actuated wheel brakes, there is a loose temporal relationship between the software loop times of the central controller and electromechanical brake units, leading to delays in braking processes, which can be hazardous and reduce vehicle stability.
Innovation Solution
Synchronizing the software loop times of nodes in the braking system via a data bus, such as a CAN bus, to ensure that messages from the central controller arrive within the target arrival time window of the electromechanical actuator units, allowing for immediate processing and adjustment of braking forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a distributed control system with independent software loop times is used for central controller and electromechanical brake units, then system autonomy and modular control are improved, but message processing delays and temporal coordination issues worsen
Solution Approach 1:
The slave control unit dynamically adjusts its software loop time based on the synchronization offset calculated from timestamp comparisons. This dynamic adaptation allows the system to maintain autonomous operation while optimizing response timing to minimize processing delays in message transmission and execution.
Solution Approach 2:
The system implements a feedback mechanism where the slave control unit compares timestamps of received messages with its local timing, calculates synchronization offsets, and adjusts its software loop time accordingly. This closed-loop timing synchronization ensures that despite independent operation, the slave unit responds to master controller commands with minimal and consistent delay.
2Device complexity
If independent software loop execution is maintained in distributed brake control units, then system complexity and coordination overhead are reduced, but braking process delays and safety risks increase
Solution Approach 1:
The slave control unit performs preliminary timing synchronization by continuously monitoring message timestamps and pre-calculating synchronization offsets before actual braking commands are executed. This preliminary timing adjustment ensures that when braking commands are received, they are processed with minimal delay, thereby maintaining safety without requiring complex real-time coordination protocols.
3Stability of the object's composition
If software loop time is fixed in distributed control nodes, then system stability and predictability are improved, but response flexibility and adaptability to varying braking conditions worsen
Solution Approach 1:
The system transitions from fixed to dynamic software loop timing by allowing the slave control unit to adjust its loop time based on synchronization requirements. This dynamic adjustment maintains system stability through controlled adaptation rather than rigid fixed timing, enabling the system to respond flexibly to varying braking conditions while preserving overall temporal coordination.
Data Source
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AI summary
The invention relates to an electronic braking system (50) for motor vehicles (60), comprising at least one wheel brake (7, 8, 9, 10) actuated by an electromechanical actuator (11, 12), wherein the electromechanical actuator (11, 12) is associated with an electronic control and/or regulating unit (WCU) (18, 19, 20) in which a data processing program for controlling and/or regulating the electromechanical actuator (11, 12) is executed, and comprising a data bus, in particular a CAN data bus, by means of which the electronic control and/or regulating unit (WCU) (18, 19, 20) associated with the electromechanical actuator (11, 12) is connected at least one additional control and/or regulating unit (ECU) (18, 19, 20), particularly a central electronic or electrohydraulic control and/or regulating unit (5). In said braking system, a temporal coordination is to be achieved between an electronic control and regulating unit (18, 19, 20) associated with an electromechanical actuator (11, 12) and an additional control and regulating unit of the braking system. To this end, the loop time of the data processing program for controlling and/or regulating the electromechanical actuator (11, 12) may be altered via the data bus.