Vehicle Motion Control Timing for Synchronized Brake Actuation
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Solution Overview
Problem
The increasing complexity of vehicle motion control systems, with over a hundred electronic control units (ECUs) interconnected via networks like CAN and Ethernet, poses a risk of unforeseen interference, leading to potential instability and the need for measures to mitigate these risks, especially with advancements in autonomous driving.
Innovation Solution
A vehicle motion control unit featuring a central controller and actuator control modules that operate in a common reference time frame, ensuring coordinated action among actuators like brakes and steering, with features such as encrypted instruction messages and synchronization mechanisms to maintain coherence and stability, even in the presence of network delays or interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a network-based communication system is used to connect multiple ECUs, then system adaptability and ease of adding/exchanging components is improved, but system reliability deteriorates due to unforeseen interference and message transmission delays
Solution Approach 1:
The patent introduces a central controller as an intermediary that receives motion control instructions and distributes them to multiple actuator control modules. This mediator coordinates message transmission and ensures that all actuators receive synchronized control signals, thereby maintaining system reliability while preserving the adaptability benefits of the network architecture.
Solution Approach 2:
The system implements feedback mechanisms where actuator control modules report their status and message reception timing back to the central controller. This feedback enables the central controller to detect and compensate for transmission delays, ensuring synchronized actuator operation and maintaining reliability in the adaptive network system.
2Device complexity
If multiple actuator control modules operate independently without centralized time coordination, then system complexity is reduced, but motion control coherence deteriorates due to dispersions in brake torque application
Solution Approach 1:
The patent establishes a common reference time frame that all actuator control modules share, creating an equipotential temporal baseline. This ensures that all modules interpret control instructions consistently and execute actions simultaneously, maintaining motion control coherence without requiring complex inter-module communication protocols.
Solution Approach 2:
The system merges the time-keeping function of all actuator control modules into a single centralized time reference managed by the central controller. This consolidation eliminates timing dispersions across modules while keeping individual module complexity low, as each module simply follows the centralized time reference.
3Speed
If instruction messages are transmitted without encryption, then communication speed is improved, but system reliability deteriorates due to potential interference and unauthorized access
Solution Approach 1:
The system applies encryption to instruction messages before transmission occurs. This preliminary protective action ensures message integrity and security is established beforehand, allowing fast transmission without compromising reliability. The encryption overhead is minimized through efficient algorithms suitable for real-time automotive communication.
Data Source
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AI summary
The present disclosure provides a vehicle motion control unit (100) for controlling motion of a vehicle (10) that comprises a control system network (8) that has communicatively coupled thereto a central controller (6), and a plurality of actuator control modules (40; 40FL, 40FR, 40RL and 40RR) each for controlling respective sets of one or more motion control actuators (45; 45FL, 45FR, 45RL and 45RR) to control a motion of the vehicle (10). The central controller is configured to transmit a respective motion control instruction message conveying a motion control instruction to one or more of the plurality of actuator control modules, a motion control instruction instructing an actuator control module to cause its set of one or more motion control actuators to perform a motion control action as a function of time in a common reference time frame. The actuator control module having received the motion control instruction message is configured to accordingly execute said motion control instruction. The present disclosure further provides a vehicle (10) comprising the vehicle motion control system, a smart brake actuator (4) for use in the vehicle motion control system and a method for controlling vehicle motion.