Distributed Controller State Synchronization via Ambient Light Feedback
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Solution Overview
Problem
Distributed control systems for building automation, such as lighting control systems, face challenges in maintaining synchronized internal states across controller nodes, leading to unreliable communication and out-of-sync output values, which can disrupt the control functions.
Innovation Solution
A wireless mesh network system where controller nodes, such as luminaires, share and synchronize their internal states based on ambient light levels, using Proportional-Integral controllers to generate correction values and transmit synchronization messages, avoiding the need for acknowledgment messages and timing constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed control nodes operate independently without centralized coordination, then system reliability and fault tolerance are improved, but internal states across nodes become out of sync leading to inconsistent output values
Solution Approach 1:
The patent implements a feedback mechanism where controller nodes periodically exchange synchronization messages containing their internal state values. Each node receives messages from other nodes, compares state values, and adjusts its own internal state to maintain consistency across the distributed system without requiring centralized coordination.
Solution Approach 2:
The patent introduces synchronization messages as an intermediary mechanism that facilitates state exchange between distributed controller nodes. These messages act as a mediator that enables nodes to share and coordinate their internal states indirectly, maintaining system-wide consistency while preserving the distributed architecture's independence and reliability.
2Reliability
If acknowledgment messages are used to ensure reliable communication between nodes, then message delivery reliability is improved, but communication overhead and message transmission load increase
Solution Approach 1:
The patent merges the synchronization function with the existing message transmission protocol. Instead of sending separate acknowledgment messages, the system combines state synchronization data with regular control messages, allowing nodes to exchange both types of information in a single communication event, thereby reducing overall message transmission overhead.
Solution Approach 2:
The patent makes synchronization messages multi-functional by designing them to serve both as state synchronization carriers and as implicit acknowledgment signals. When a node receives and processes a synchronization message, it automatically acknowledges receipt by incorporating the received state information into its own state, eliminating the need for separate acknowledgment messages.
3Stability of the object's composition
If timing constraints are imposed to synchronize controller operations, then output consistency is improved, but system flexibility and ease of operation are reduced
Solution Approach 1:
The patent implements dynamic synchronization where nodes adjust their internal states based on received synchronization messages rather than operating under rigid timing constraints. The synchronization process adapts to the actual state values exchanged between nodes, allowing flexible timing while maintaining output consistency through state comparison and adjustment.
Solution Approach 2:
The patent changes the synchronization approach from time-based parameter control to state-value parameter control. Instead of enforcing synchronized operation through timing parameters, the system uses internal state values as the synchronization parameter, allowing nodes to operate at different times while maintaining consistent outputs through state value exchange and comparison.
Data Source
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AI summary
A distributed control system, comprising a data network with a plurality of controller nodes that maintain and share their internal states with one another while controlling a function. The controller nodes can be luminaires that are capable of controlling the ambient lighting within a building area. There are one or more ambient light sensors within the data network for sensing and reporting the ambient light level. The controller luminaire nodes are members of a defined group of nodes that share, with one another, information for synchronizing their internal states, based in part on the ambient light levels that the one or more sensors are reporting. Meanwhile, each luminaire node also continually updates its own internal state based on the synchronization data received from the other nodes.