Teleoperation Model Synchronization Under Communication Delay
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Solution Overview
Problem
Model-mediated teleoperation systems face significant challenges due to communication delays, which can lead to outdated models of the controlled environment, resulting in reduced feedback accuracy and increased risk, especially in dynamic situations.
Innovation Solution
Implementing a method where both the master and slave systems use time-stamped model versions to ensure that both systems operate on the most current understanding of the environment, allowing for accurate and timely reactions by identifying and applying the relevant model version based on the timestamp, thereby reducing the negative impacts of delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If communication delay is reduced, then feedback accuracy is improved, but system complexity increases due to the need for time-stamped model version tracking and coordination
Solution Approach 1:
The system performs preliminary actions by continuously updating and storing multiple versions of the environment model with time stamps before they are needed for control decisions. This allows the slave system to have model versions ready and available when control commands arrive, eliminating the need to wait for model updates during time-critical operations.
Solution Approach 2:
The system implements feedback mechanisms where the slave system sends sensor data and model version information back to the master system, and the master system responds with updated control commands that include time stamp information. This closed-loop feedback ensures both systems remain synchronized on the current environment state despite communication delays.
2Reliability
If model updates are transmitted more frequently, then environment state accuracy is improved, but communication bandwidth consumption increases
Solution Approach 1:
The system extracts only the essential time stamp information from model updates and transmits it separately from the full model data. The slave system uses this time stamp to identify and retrieve the corresponding model version from its local storage, avoiding the need to continuously transmit complete model updates over the communication channel.
Solution Approach 2:
The slave system creates and maintains local copies of the environment model with time stamps. When control commands arrive, the slave system copies the appropriate model version from its local storage based on the time stamp in the command, eliminating the need to receive and process full model updates for every control cycle.
3Measurement precision
If the slave system always uses the most recent model version, then control accuracy is improved, but stability decreases when the master and slave systems operate on different model versions
Solution Approach 1:
The time stamp acts as an intermediary that bridges the master and slave systems. The master system includes the time stamp of the model version used to generate a control command in the transmitted command. The slave system uses this time stamp to identify and select the corresponding model version from its local storage, ensuring both systems operate on matching model versions and maintaining stability.
Solution Approach 2:
The slave system preliminarily organizes and stores multiple model versions with their associated time stamps before they are needed for control operations. This preliminary organization allows the slave system to quickly and accurately match the time stamp in incoming control commands with the corresponding model version, ensuring consistency without introducing delays.
Data Source
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AI summary
A method applicable in a slave system or a master system, when the master system is reacting on an environment via the slave system, connected to a master system, via a communication system. When a control message is determined and sent from the master system to the slave system, the control message is accompanied with a time stamp, indicative of the master model version of the environment which was applied when the control data was determined by the master system. When data, triggered by data provided from the environment to the slave system in the form of updated sensor data is provided from the slave system to the master system, also that data, indicative of an updated slave model version of the environment made by the slave system, is provided to the master system, together with a time stamp, indicative of when the update of the slave model version was made. By applying the suggested time stamp, a coordination of model versions can be obtained between the master system and the slave system.