Vehicle Control System Synchronizing Update Cycles
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Solution Overview
Problem
Differing update cycles among sensors and subsystems in autonomous vehicles can lead to inefficient, jerky, or imprecise control of vehicle motion, such as stopping short of or alternately riding up on/falling back from a leading vehicle, due to asynchronous reactions between brake and engine-control systems.
Innovation Solution
A vehicle-control system with multiple controllers (first, second, and third) that allows precise command issuance to subsystems, utilizing a process to update identifiers for state-of-motion and achieve target values, ensuring smoother control by coordinating update cycles across the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If subsystems operate with different update cycles, then each subsystem can function independently with its own timing, but the overall vehicle control becomes jerky and imprecise
Solution Approach 1:
The patent merges the update cycles of multiple subsystems (brake, engine control, steering) into a unified coordination mechanism. The virtual driver sends coordinated commands to multiple subsystems simultaneously, ensuring they update together based on a common timing reference, thereby eliminating jerky motion while preserving independent subsystem functionality.
Solution Approach 2:
The virtual driver acts as an intermediary that receives state information from all subsystems and distributes coordinated control commands back to them. This intermediary layer synchronizes the update cycles by mediating between subsystems with different native timing requirements, ensuring precise coordinated control without requiring direct modification of each subsystem's internal timing.
2Device complexity
If the virtual driver update cycle is too long, then processing complexity is reduced, but the vehicle may stop short of or past the intended target
Solution Approach 1:
The system performs preliminary calculations of the optimal update cycle duration based on vehicle speed, distance to target, and subsystem response characteristics. This preliminary action determines the appropriate timing parameters before execution, allowing the virtual driver to operate with a manageable update cycle while still achieving precise stopping positions through pre-computed timing adjustments.
3Speed
If brake and engine-control systems react in alternating manner, then each system can respond quickly to commands, but the vehicle alternately rides up on and falls back from the leading vehicle
Solution Approach 1:
The patent implements periodic coordinated updates where the virtual driver sends synchronized commands to brake and engine-control systems at regular intervals. This periodic action ensures both systems respond at their maximum speed while maintaining stable coordination, preventing alternating reactions that cause vehicle oscillation. The periodic timing is optimized to match the slowest responding subsystem while keeping faster subsystems synchronized.
Data Source
AI summary
A current value of a state-of-motion from a second controller can be received by a first controller. The first controller determines a subset of a target value of the state-of-motion to be achieved by a subsystem and transmits a command to a third controller in communication with the subsystem to achieve the subset of the target value of the state-of-motion. The third controller commands the subsystem to approach the subset of the target value of the state-of-motion.