Automating Industrial Cable Assembly in Constrained Environments: Practical Approaches and Current Challenges

Core Concepts

Robotic solutions for the complete cable assembly process, including cable gripping, routing, and plug insertion, in tight industrial workspaces with realistic tolerances and space constraints.

Abstract

This paper presents an analysis of the complete industrial cable assembly process and demonstrates solutions for two types of connectors - FASTON and a cubical industrial connector. The key highlights are:

Cable Gripping:

Customized gripper fingers with form-fit designs to reliably grip both the cable and plug.
An orientation correction device to ensure consistent plug orientation for the second plug insertion.

Cable Routing:

A method to route the cable by sliding the gripper along the cable and inserting it into the routing points.
Challenges in routing the cable in tight workspaces with limited robot maneuverability.

Plug Insertion:

A contact-based insertion method for the FASTON plug to compensate for tight tolerances.
Direct insertion using position control for the industrial connector with more relaxed tolerances.

Experimental Results:

The proposed solutions can reliably perform the complete cable assembly process for both connector types.
Identified limitations in robot accuracy, cable routing, and the need for a finger switching system.
Recommendations for improving the automation-friendliness of product design.

The paper demonstrates practical robotic solutions for industrial cable assembly tasks, while also highlighting the current challenges and opportunities for further improvements.

Stats

The duration of each assembly phase (in seconds) is:

FASTON Connector: Gripping 5s, Insertion 5s, Routing 48s, Orientation Correction 9s
Industrial Connector: Gripping 9s, Insertion 5s
The system achieved a 3.0mm tolerance window in the y-direction for the FASTON plug insertion.

Quotes

"Feasibility for the robotic grasping and insertion of plugs, as well as the manipulation of cables, have been shown in research settings. However, in many industrial tasks the complete process from picking, insertion, routing, and validation must be solved with one system."
"The proposed method can perform cable assembly with mere position control, foregoing complex control approaches."
"The proposed finger mechanism consists of four beams, whereby two beams are double the length of the other two. One end of the long beams is attached to the horizontally moving gripper, while their midpoint is attached to the shorter beams. Both of the second end of the long beams are attached to the finger tip, which moves vertically."

Key Insights Distilled From

Industrial Cabling in Constrained Environments: a Practical Approach and Current Challenges

by Tanureza Jay... at arxiv.org 04-18-2024

https://arxiv.org/pdf/2404.10829.pdf

Deeper Inquiries

How can the cable routing process be further automated to reduce the teaching effort and cycle time?

To enhance the automation of the cable routing process and minimize the teaching effort and cycle time, several strategies can be implemented:

Advanced Path Planning Algorithms: Utilize sophisticated path planning algorithms that can automatically generate optimal routes for the cables to follow. These algorithms should take into account the geometry of the workspace, the location of routing points, and any obstacles present to plan efficient cable paths.

Machine Learning for Teaching: Implement machine learning algorithms that can learn from demonstrations provided by human operators during the teaching phase. This can help the robot understand how to navigate the cable routing process more effectively and reduce the need for manual programming.

Force Sensing and Feedback: Incorporate force sensors into the gripper or end effector to provide feedback on the amount of force being applied during cable routing. This feedback can help the robot adjust its grip and movement to ensure smooth and accurate routing without causing damage to the cables or components.

Vision Systems for Cable Tracking: Integrate vision systems that can track the position and orientation of the cables in real-time. This visual feedback can assist the robot in accurately manipulating the cables and inserting them into routing points without the need for precise manual positioning.

By implementing these strategies, the cable routing process can be automated more effectively, reducing the teaching effort and cycle time required for successful cable assembly.

What alternative gripper designs or actuation mechanisms could enable a more versatile finger switching system for handling different connector types?

To create a more versatile finger switching system for handling various connector types, the following alternative gripper designs or actuation mechanisms can be considered:

Modular Gripper Fingers: Develop gripper fingers that can be easily swapped or reconfigured to accommodate different connector shapes and sizes. These modular fingers can be equipped with interchangeable tips or attachments to provide a customized grip for each connector type.

Soft Grippers: Implement soft grippers made of flexible materials that can conform to the shape of different connectors. These grippers can adapt their shape and grip strength based on the connector being handled, allowing for a more versatile handling capability.

Compliant Mechanisms: Utilize compliant mechanisms in the gripper design to provide flexibility and adaptability when gripping various connector types. Compliant mechanisms can adjust their stiffness and compliance to securely hold different shapes without the need for complex actuation systems.

Parallel Jaw Grippers with Variable Width: Design parallel jaw grippers with adjustable jaw width to accommodate connectors of different sizes. By incorporating actuators that can dynamically change the distance between the jaws, the gripper can effectively handle a range of connector dimensions.

By exploring these alternative gripper designs and actuation mechanisms, a more versatile finger switching system can be developed to enhance the handling of different connector types in the cable assembly process.

What advancements in sensor technologies or control strategies could help overcome the limitations imposed by tight workspace constraints and improve the overall robustness of the cable assembly process?

To address the challenges posed by tight workspace constraints and enhance the robustness of the cable assembly process, the following advancements in sensor technologies and control strategies can be leveraged:

Force/Torque Sensors: Integrate advanced force/torque sensors into the gripper or end effector to provide real-time feedback on the forces exerted during cable handling. This sensor data can enable the robot to adjust its grip strength and positioning to prevent damage to the cables or components in confined spaces.

3D Vision Systems: Implement 3D vision systems that can accurately perceive the environment and detect obstacles or cable misalignments in tight workspaces. This visual feedback can guide the robot in navigating complex cable routing paths and ensuring precise insertion of connectors.

Predictive Control Algorithms: Develop predictive control algorithms that can anticipate potential collisions or constraints in the workspace and proactively adjust the robot's movements to avoid such issues. By predicting and mitigating obstacles in advance, the cable assembly process can be executed more smoothly and efficiently.

Adaptive Gripping Strategies: Employ adaptive gripping strategies that can dynamically adjust the grip force, orientation, and position of the gripper based on sensor feedback. This adaptability allows the robot to handle variations in cable shapes and workspace constraints effectively, improving the overall robustness of the assembly process.

By incorporating these advancements in sensor technologies and control strategies, the cable assembly process can overcome limitations imposed by tight workspace constraints and achieve greater efficiency and reliability in industrial cabling tasks.