Single Cycle Offset Adjustment for Traffic Signal Controllers
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Solution Overview
Problem
Current offset correction methods in traffic signal controllers take several signal cycles to complete, causing delays and counteracting the goal of maximizing vehicle throughput by dwelling in a single phase for extended periods during transitions between signal control plans.
Innovation Solution
A method for single cycle offset adjustment that calculates the offset between current and new signal control plans, adjusting phase times in the next cycle by reducing or increasing them based on the offset percentage relative to the cycle length, allowing for seamless transitions within a single cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current offset correction methods are used to transition between signal control plans, then the offset correction is completed, but the transition takes several signal cycles causing delays and reducing vehicle throughput
Solution Approach 1:
The patent calculates the offset between current and new signal control plans in advance, before the transition occurs. This preliminary calculation allows the system to prepare the correction strategy ahead of time, enabling the offset to be corrected within a single cycle rather than requiring multiple cycles for gradual adjustment.
Solution Approach 2:
The patent dynamically adjusts phase time parameters within the next cycle based on the calculated offset. By changing the duration of phases proportionally to the offset amount, the system can absorb and correct the timing discrepancy in one cycle, eliminating the need for multi-cycle gradual correction and reducing transition delays.
2Reliability
If current offset correction methods are used to transition between signal control plans, then the offset correction is completed, but the system dwells in a single phase for extended periods counteracting the goal of maximizing vehicle throughput
Solution Approach 1:
The patent makes the phase timing dynamic by adjusting phase durations based on the calculated offset. Rather than dwelling in a single phase for extended periods, the system dynamically redistributes time across phases proportionally to the offset amount, maintaining continuous traffic flow and maximizing vehicle throughput while still achieving offset correction.
Solution Approach 2:
The patent changes phase time parameters within the next cycle to reflect the offset correction needs. By proportionally increasing or decreasing phase durations based on the offset, the system corrects timing discrepancies without causing extended dwelling in single phases, thus maintaining high vehicle throughput.
3Speed
If phase times are adjusted to correct offset within a single cycle, then transition speed is improved, but phase timing precision must be carefully controlled to maintain traffic flow
Solution Approach 1:
The patent incorporates a decision block that evaluates whether the calculated offset is less than a threshold percentage of the cycle length. This feedback mechanism ensures that phase time adjustments are only made when appropriate, preventing over-correction and maintaining precise control over phase timing while enabling rapid single-cycle transitions.
Solution Approach 2:
The patent carefully controls the magnitude of phase time adjustments by basing them on the calculated offset as a percentage of the cycle length. This precise parameter control ensures that phase durations are adjusted just enough to correct the offset without disrupting traffic flow, achieving both fast transition and timing precision.
Data Source
AI summary
Embodiments include a method for single cycle offset adjustment for a traffic signal includes receiving a current signal control plan and a new signal control plan. The method also includes calculating an offset between the current signal control plan and a new signal control plan and determining if the offset is less than a threshold percentage of a cycle length of the new signal control plan. If the offset is less than a threshold percentage of the cycle length, the method includes reducing a time period of each phase of a next cycle of the new signal control plan. If the offset is greater than the threshold percentage of the cycle length, the method includes increasing the time period of each phase of the next cycle of the new signal control plan. The method also includes executing the new signal control plan.