Phase 0 - Concept & Motion Feasibility Direction

0.1 Provisional Robot Selection

For preliminary motion validation, the ABB IRB 7710 (280 kg payload, 3.5 m reach) was selected. This configuration provides sufficient reach for sectional tunnel crown and wall inspection studies while offering documented industrial foundation load data for future structural validation.

Final robot selection will be confirmed during SIP408 after rail platform geometry, stability constraints, and structural load case definition are completed.

0.2 RobotStudio Station Architecture

The current RobotStudio station includes:

Simplified tunnel envelope
Provisional rail-aligned base geometry
ABB IRB 7710 industrial robot
Tool changer interface
Simplified GPR payload model

The rail platform is intentionally modeled as simplified geometry at this stage to isolate motion feasibility prior to structural validation and wheel interface modeling scheduled for SIP408.

IRB7710 3D Volume

A reach study was conducted to verify that the selected robot configuration can access the defined tunnel inspection arc without violating joint limits or entering singular configurations.

The 3.5 m reach configuration provides adequate radial access to sectional crown and sidewall regions from a rail-aligned mounting position.

0.4 Sectional Arc Inspection Path

0.5 RAPID Path Programming

Inspection Trajectory with the tool frame aligned to the surface.

A sectional arc inspection trajectory was developed to simulate ground-penetrating radar sweep coverage along the tunnel crown.

The tool frame is maintained in a controlled orientation relative to the tunnel surface to achieve consistent sensor alignment and a 25 mm standoff.

This implementation validates:

Programmed arc repeatability
Orientation control
Collision detection within the tunnel envelope

  
    PROC main()
    MoveAbsJ jHome,v1500,z100,tGPR2\WObj:=wobj0;
    Path_10;
    MoveAbsJ jHome,v1500,z100,tGPR2\WObj:=wobj0;
ENDPROC

PROC Path_10()
    MoveJ Target_380,v1000,z100,tGPR3\WObj:=wobj0;
    MoveL Target_390,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_400,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_410,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_420,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_430,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_440,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_450,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_460,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_470,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_480,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_490,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_500,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_510,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_520,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_530,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_540,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_550,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_560,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_570,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_580,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_590,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_600,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_610,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_620,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_630,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_640,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_650,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_660,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_670,v300,z10,tGPR3\WObj:=wobj0;
    MoveL Target_680,v300,z10,tGPR3\WObj:=wobj0;
    MoveJ Target_690,v1000,z100,tGPR3\WObj:=wobj0;
ENDPROC


  

Sectional Arc Inspection Demonstration – Motion Feasibility Study

0.3 Work Envelope Validation

IRB7710 2D Volume

The arc sweep is executed using linear motion commands with defined velocity and zone parameters. The active tool frame (toolGPR) ensures consistent orientation throughout traversal.

0.6 Motion Demonstration

The robot successfully completed the defined arc sweep without environmental collision or configuration instability.

0.7 Phase 0 Summary

Validated to Date (Pre-SIP408)

Conceptual rail-mounted robotic architecture
Provisional robot configuration (IRB 7710)
Sectional tunnel arc coverage feasibility
Tool orientation control during sweep
Envelope-based collision verification

Planned for SIP408

Final robot model selection
Track gauge assumption freeze
Wheelset + rail interface modeling
Robot mounting plate bolt pattern definition
ABB “Loads on Foundation” extraction
Static FEA (FoS ≥ 3.0)
Deflection validation (≤ 1.0 mm)
Anti-tip stability margin (≥ 1.5×)
EOAT + GPR mass/CG definition
Full inspection cycle validation

Engineering Process

Phased Validation Roadmap – Subway Sentinel