Distributed Control Gain Correction for Asymmetric Delay Consensus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In distributed control systems, time delays in signal information transfer between agents can cause state indicator values to fail to converge to a consensus value, leading to oscillations and deviations from the expected average value, making stable control challenging, especially in networks with asymmetric communication delays.
Innovation Solution
A new control protocol is introduced where each control device adjusts its control gain based on the communication delay times for both the transmission and reception of state indicator values, using the latest values and incorporating a control gain correction to compensate for delays, ensuring convergence to a consensus value even with asymmetric delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional control protocol is used in a distributed control system with communication networks, then the system structure is simple and easy to implement, but time delays in signal information transfer cause state indicator values to fail to converge to a consensus value, leading to oscillations and deviations from the expected average value
Solution Approach 1:
The patent modifies the control protocol by introducing a control gain correction mechanism that adjusts the control gain based on communication delay times. Specifically, the control gain is corrected using the formula Gij = Γ * max(Δij, Δji), where Δij and Δji are the communication delay times from agent i to j and from agent j to i respectively. This parameter change compensates for asymmetric communication delays and ensures convergence to the consensus value while maintaining system reliability.
2Adaptability or versatility
If communication delay compensation is implemented using symmetric delay assumptions, then the control protocol is simpler, but it cannot handle asymmetric communication delays which occur in real networks, leading to instability
Solution Approach 1:
The patent explicitly addresses asymmetric communication delays by using the formula Gij = Γ * max(Δij, Δji), which considers the maximum of the two directional delays (from i to j and from j to i). This asymmetric approach allows the control protocol to handle real-world network conditions where delays in different directions are not equal, thereby improving adaptability while managing complexity through a straightforward correction mechanism.
3Speed
If the control gain is increased to accelerate convergence, then the convergence speed improves, but oscillations are amplified and stability is compromised in the presence of communication delays
Solution Approach 1:
The patent implements a feedback mechanism where the control gain is dynamically corrected based on measured communication delay times. The control gain correction Gij = Γ * max(Δij, Δji) provides feedback about the network conditions, allowing the system to adjust the control gain appropriately. This feedback loop ensures that convergence speed is optimized without compromising stability, as the control gain is adapted to the actual communication conditions rather than being fixed or simply increased.
Data Source
AI summary
A system includes a plurality of control devices that respectively control the states of a plurality of apparatuses and are connected to each other via communication lines. When each of the control devices determines a state target value of its own apparatus using the current state indicator value of the own apparatus, and the distributed controller input which is a function of the state indicator value of an apparatus adjacent to the own apparatus and the state indicator value of the own apparatus, the control gain which adjusts contribution of the distributed controller input to the state target value is determined based on a communication delay time between the control devices.