Remote Vehicle Latency Control With Cancelable Emergency Stop
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Solution Overview
Problem
Existing methods for controlling remotely operated vehicles (ROVs) are limited by high communication latency thresholds, which restrict the maximum speed of the vehicle and may lead to frequent interruptions in operation.
Innovation Solution
A method that monitors communication link latency and requests an emergency stop if the latency exceeds a predetermined threshold. The emergency stop is cancelled if the communication link is recovered within a brake reaction time period, allowing for a lower latency threshold without increasing the number of emergency stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a higher latency threshold is set to avoid frequent interruptions, then the operation continuity is improved, but the maximum allowed speed of the vehicle must be reduced to ensure emergency stop within maximum distance
Solution Approach 1:
The patent applies dynamics by making the latency threshold adaptive rather than static. The threshold is dynamically adjusted based on the vehicle's current speed: at lower speeds, a higher threshold allows operation continuity; at higher speeds, the threshold is lowered to ensure safety. This dynamic adaptation resolves the contradiction by allowing the system to optimize for productivity at low speeds and for safety at high speeds.
Solution Approach 2:
The patent changes the parameter of latency threshold based on operating conditions. By varying the threshold value according to vehicle speed and other factors, the system can maintain operation continuity when appropriate while ensuring emergency stop capability is preserved. This parameter change strategy allows the system to navigate the trade-off between productivity and speed restrictions.
2Speed
If a lower latency threshold is set to allow higher vehicle speed, then the maximum allowed speed is improved, but the number of emergency stop interruptions increases
Solution Approach 1:
The system dynamically adjusts the latency threshold based on real-time vehicle speed. When the vehicle travels at lower speeds, a higher threshold is applied to maintain operation continuity. When the vehicle accelerates to higher speeds, the threshold is automatically lowered to ensure safety. This dynamic behavior allows the system to achieve higher maximum speeds without causing excessive interruptions, as the threshold adaptation compensates for the increased speed.
3Productivity
If a high latency threshold is used, then operation interruptions are reduced, but the emergency stop distance increases beyond acceptable limits at high speeds
Solution Approach 1:
The patent changes the latency threshold parameter based on vehicle speed to control emergency stop distance. At high speeds, where stopping distance is a critical safety concern, the threshold is lowered to ensure that emergency stops are triggered at appropriate distances. At lower speeds, the threshold can be higher without compromising stop distance. This parameter adaptation resolves the contradiction between operation continuity and emergency stop distance constraints.
Data Source
AI summary
Embodiments of the invention pertain to a method of controlling a remotely operated vehicle operated from a remote operation station via a communication link, the method comprising: monitoring a latency (L) of the communication link, requesting (S2) an emergency stop maneuver in response to the latency exceeding a predetermined threshold (T), and cancelling (S3) the requested emergency stop maneuver, in response to the communication link being recovered within a brake reaction time (A). Embodiments of the invention also relate to a remotely operated vehicle having a control unit configured to: monitor a latency (L) of a communication link between the vehicle and a remote operation station, request an emergency stop maneuver in response to the latency exceeding a predetermined threshold (T), and cancel the requested emergency stop maneuver, in response to the communication link being recovered within a brake reaction time period (A).