Design of a Bionic Self-Insulating Mechanical Arm for Concealed Space Inspection in the Live Power Cable Tunnels

Adopting mobile robots for high voltage (HV) live-line operations can mitigate personnel casualties and enhance operational efficiency. However, conventional mechanical arms cannot inspect concealed spaces in the power cable tunnel because their joint integrates metallic motors or hydraulic serial-d...

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Main Authors: Jingying Cao, Jie Chen, Xiao Tan, Jiahong He
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/13/7350
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author Jingying Cao
Jie Chen
Xiao Tan
Jiahong He
author_facet Jingying Cao
Jie Chen
Xiao Tan
Jiahong He
author_sort Jingying Cao
collection DOAJ
description Adopting mobile robots for high voltage (HV) live-line operations can mitigate personnel casualties and enhance operational efficiency. However, conventional mechanical arms cannot inspect concealed spaces in the power cable tunnel because their joint integrates metallic motors or hydraulic serial-drive mechanisms, which limit the arm’s length and insulation performance. Therefore, this study proposes a 7-degree-of-freedom (7-DOF) bionic mechanical arm with rigid-flexible coupling, mimicking human arm joints (shoulder, elbow, and wrist) designed for HV live-line operations in concealed cable tunnels. The arm employs a tendon-driven mechanism to remotely actuate joints, analogous to human musculoskeletal dynamics, thereby physically isolating conductive components (e.g., motors) from the mechanical arm. The arm’s structure utilizes dielectric materials and insulation-optimized geometries to reduce peak electric field intensity and increase creepage distance, achieving intrinsic self-insulation. Furthermore, the mechanical design addresses challenges posed by concealed spaces (e.g., shield tunnels and multi-circuit cable layouts) through the analysis of joint kinematics, drive mechanisms, and dielectric performance. The workspace of the proposed arm is an oblate ellipsoid with minor and major axes measuring 1.25 m and 1.65 m, respectively, covering the concealed space in the cable tunnel, while the arm’s quality is 4.7 kg. The maximum electric field intensity is 74.3 kV/m under 220 kV operating voltage. The field value is less than the air breakdown threshold. The proposed mechanical arm design significantly improves spatial adaptability, operational efficiency, and reliability in HV live-line inspection, offering theoretical and practical advancements for intelligent maintenance in cable tunnel environments.
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spelling doaj-art-d18d867844da40e18bef71453ef7eacb2025-08-20T03:16:52ZengMDPI AGApplied Sciences2076-34172025-06-011513735010.3390/app15137350Design of a Bionic Self-Insulating Mechanical Arm for Concealed Space Inspection in the Live Power Cable TunnelsJingying Cao0Jie Chen1Xiao Tan2Jiahong He3Electric Power Research Institute of State Grid Jiangsu Electric Power Co., Ltd., Nanjing 211103, ChinaElectric Power Research Institute of State Grid Jiangsu Electric Power Co., Ltd., Nanjing 211103, ChinaElectric Power Research Institute of State Grid Jiangsu Electric Power Co., Ltd., Nanjing 211103, ChinaSchool of Electrical Engineering, Southeast University, Nanjing 210096, ChinaAdopting mobile robots for high voltage (HV) live-line operations can mitigate personnel casualties and enhance operational efficiency. However, conventional mechanical arms cannot inspect concealed spaces in the power cable tunnel because their joint integrates metallic motors or hydraulic serial-drive mechanisms, which limit the arm’s length and insulation performance. Therefore, this study proposes a 7-degree-of-freedom (7-DOF) bionic mechanical arm with rigid-flexible coupling, mimicking human arm joints (shoulder, elbow, and wrist) designed for HV live-line operations in concealed cable tunnels. The arm employs a tendon-driven mechanism to remotely actuate joints, analogous to human musculoskeletal dynamics, thereby physically isolating conductive components (e.g., motors) from the mechanical arm. The arm’s structure utilizes dielectric materials and insulation-optimized geometries to reduce peak electric field intensity and increase creepage distance, achieving intrinsic self-insulation. Furthermore, the mechanical design addresses challenges posed by concealed spaces (e.g., shield tunnels and multi-circuit cable layouts) through the analysis of joint kinematics, drive mechanisms, and dielectric performance. The workspace of the proposed arm is an oblate ellipsoid with minor and major axes measuring 1.25 m and 1.65 m, respectively, covering the concealed space in the cable tunnel, while the arm’s quality is 4.7 kg. The maximum electric field intensity is 74.3 kV/m under 220 kV operating voltage. The field value is less than the air breakdown threshold. The proposed mechanical arm design significantly improves spatial adaptability, operational efficiency, and reliability in HV live-line inspection, offering theoretical and practical advancements for intelligent maintenance in cable tunnel environments.https://www.mdpi.com/2076-3417/15/13/7350cable tunnelbionic mechanical armlive-line operationself-insulation
spellingShingle Jingying Cao
Jie Chen
Xiao Tan
Jiahong He
Design of a Bionic Self-Insulating Mechanical Arm for Concealed Space Inspection in the Live Power Cable Tunnels
Applied Sciences
cable tunnel
bionic mechanical arm
live-line operation
self-insulation
title Design of a Bionic Self-Insulating Mechanical Arm for Concealed Space Inspection in the Live Power Cable Tunnels
title_full Design of a Bionic Self-Insulating Mechanical Arm for Concealed Space Inspection in the Live Power Cable Tunnels
title_fullStr Design of a Bionic Self-Insulating Mechanical Arm for Concealed Space Inspection in the Live Power Cable Tunnels
title_full_unstemmed Design of a Bionic Self-Insulating Mechanical Arm for Concealed Space Inspection in the Live Power Cable Tunnels
title_short Design of a Bionic Self-Insulating Mechanical Arm for Concealed Space Inspection in the Live Power Cable Tunnels
title_sort design of a bionic self insulating mechanical arm for concealed space inspection in the live power cable tunnels
topic cable tunnel
bionic mechanical arm
live-line operation
self-insulation
url https://www.mdpi.com/2076-3417/15/13/7350
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AT xiaotan designofabionicselfinsulatingmechanicalarmforconcealedspaceinspectioninthelivepowercabletunnels
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