Robot Control Tunneling for Deterministic Wireless Frame Timing

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Solution Overview

Problem

Current industrial robot control systems face challenges in using wireless connections due to delay and jitter issues, which are not adequately addressed by existing solutions that fail to consider the specific requirements of state-of-the-art industrial protocols, making it difficult to transition from wired to wireless communication effectively.

Innovation Solution

A tunneling unit is introduced to emulate wired connectivity between robot devices and a controller by receiving and timestamping uplink frames, determining relative time offsets, and buffering them to ensure simultaneous delivery, thereby mitigating delay and jitter in wireless transmissions and maintaining deterministic data frame transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless connection is used for robot control, then flexibility and ease of deployment are improved, but transmission delay and jitter increase

Engineering Contradiction:

Improveease of deploymentVSAvoidtransmission reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces a wireless connection as an intermediary medium between the controller and robot devices, replacing traditional wired connections. This mediator enables flexible deployment while managing transmission challenges through protocol design and error correction mechanisms inherent in wireless communication systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent adjusts transmission parameters such as packet size, transmission power, and modulation schemes to optimize wireless communication performance. By dynamically changing these parameters, the system maintains reliable control signals while benefiting from wireless flexibility and adaptability to different environmental conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If retransmission mechanisms are added to wireless connection, then transmission reliability is improved, but transmission delay increases

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidtransmission delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements forward error correction (FEC) codes that add redundant data to transmitted packets in advance. This preliminary action allows the receiver to correct errors without requiring retransmission, thereby improving reliability while minimizing additional delay compared to retransmission-based approaches.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies selective retransmission mechanisms where only packets with errors are retransmitted rather than all packets. This partial action approach maintains reliability for critical control signals while reducing overall transmission delay by avoiding unnecessary retransmissions of correctly received packets.

Inventive Principle:

Principle #16Partial or excessive action

3Stability of the object's composition

If update time of industrial protocol is increased, then wireless connection stability is improved, but control responsiveness deteriorates

Engineering Contradiction:

Improveconnection stabilityVSAvoidcontrol responsiveness

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent divides control communication into different priority levels and message types. Critical control commands use shorter update intervals with higher priority, while non-critical telemetry data uses longer intervals. This segmentation allows the system to maintain connection stability for overall communication while preserving fast responsiveness for time-critical control functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic control cycles with fixed update times optimized for wireless transmission. By using regular periodic intervals rather than event-driven communication, the system achieves stable predictable timing that improves wireless connection reliability while maintaining adequate control responsiveness through appropriate cycle duration selection.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS11277807B2Method and arrangement for deterministic delivery of data traffic over wireless connection

Publication Date: 2022.03.15 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present disclosure relates to delivery of data traffic over a wireless connection. In more particular, it relates to methods, a tunneling unit (208), and system for emulating wired connectivity between two or more robot devices (202, 204) and a controller (222). Buffering (212) of data frames, from two or more robot devices, received up-streams a wireless access network (206) is performed. Based on the time-stamps extracted (210) from data frames a relative time offset is determined for the two or more robot devices. Buffered uplink frames are forwarded (216) to the controller in a pre-define order, enabling using the relative time offset when forwarding downlink frames (232), being received over the wireless access network (206), to said two or more robot devices, such the that the downlink frames reach each one of two or more robot devices simultaneously. A deterministic delivery of data frames over a wireless connection is provided.