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Deliverable D1.2 Dissemination Level (PU) 731968–BADGER

October 2018 1 UC3M

ICT-25-2016-2017: Advanced robot capabilities research and take-up

Project Title:

Robot for Autonomous Underground Trenchless Operations, Mapping and Navigation

BADGER Grant Agreement No: 731968

Research and Innovation Action (RIA)

Deliverable

D1.2. Overall system functionalities and system specifications

Deliverable No. D1.2

Workpackage No.

WP1 Workpackage Title and task type

Robotic system specifications, tunnelling specifications and system architecture

Task No. T1.3

Task Title Systems Engineering & Interface Engineering

Lead beneficiary UC3M

Dissemination level PU

Nature of Deliverable Report

Delivery date 30 June 2017

Status D

File Name: BADGER_Deliverable_1.2.doc

Project start date, duration 01 January 2017, 36 Months

This project has received funding from the European Union’s Horizon 2020 Research and

innovation programme under Grant Agreement n°731968

Ref. Ares(2018)5390388 - 19/10/2018


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Authors List

Leading Author (Editor)

Surname Initials Beneficiary Name Contact email

Menéndez E. UC3M [email protected]

Marín M. UC3M [email protected]

Co-authors (in alphabetic order)

# Surname Initials Beneficiary Name Contact email

1 Fischer S. TT [email protected]

2 Giakoumis D. CERTH [email protected]

3 Kouros G. CERTH [email protected]

4 Lalas A. CERTH [email protected]

5 Liberis Z. CERTH [email protected]

6 Molina R. ROB [email protected]

7 Simi A. IDS [email protected]

8 Vartholomeos P. SILO [email protected]

9 Worrall K. UoG [email protected]

Reviewers List

List of Reviewers (in alphabetic order)

# Surname Initials Beneficiary Name Contact email

1 Giakoumis D. CERTH [email protected]

2 Harkness P. UoG [email protected]

3 Simi A. IDS [email protected]


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Document history

Version Date Status Modifications made by

1.0 02/23/2017 1st Draft Elisabeth Menéndez

2.0 06/30/2017 Final Elisabeth Menéndez

3.0 10/19/2018 2nd Submission Marcos Marín


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List of definitions & abbreviations

Abbreviation Definition

WOB Weight on Bit

GPR Ground Penetrating Radar

SLAM Simultaneous Localization And Mapping


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Executive Summary The goal of BADGER (RoBot for Autonomous UnDerGround Trenchless OpERations, Mapping and Navigation) is to design and develop an integrated underground robotic system for autonomous construction of subterranean small-diameter and highly curved tunnel networks in urban environments. For that, advanced robotics control techniques will be used such as localization, mapping and autonomous navigation; sensor fusion including underground odometry and georadar; adaptation behaviours for different soils; machine learning; etc.

The robotic system will enable the execution of tasks in different application domains of high societal and economic impact including trenchless constructions (cabling and piping) installations, search and rescue operations, remote science and exploration applications, among others.

In this deliverable BADGER system functionalities and specifications are defined.


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Table of Contents Robot for Autonomous Underground Trenchless Operations, Mapping and Navigation ................................................................................................ 1 List of definitions & abbreviations ............................................................ 4 Executive Summary .................................................................................. 5 List of figures ........................................................................................... 7 List of tables ............................................................................................ 8 1. Introduction .................................................................................... 9

1.1 Scope of the deliverable .................................................................... 9 1.2 Relation to other deliverables ............................................................ 9 1.3 Deliverable structure ...................................................................... 10

2. System model procedure ............................................................... 11 3. Overall System functionalities and specifications ......................... 12

3.1 Hardware functionalities and specifications of the system .................... 13 3.1.1 Drilling head and transportation of cuttings mechanism functionalities and specifications ............................................................ 13 3.1.2 Propulsion mechanism functionalities and specifications ............... 17 3.1.3 Steering mechanism functionalities and specifications ................. 20 3.1.4 Tunnel wall support functionalities and specifications ................... 22 3.1.5 On-board GPR functionalities and specifications .......................... 24 3.1.6 Surface rover functionalities and specifications ........................... 25

3.2 Software functionalities and specifications ......................................... 28 3.2.1 Preliminary block diagram representation of SW architecture........ 28 3.2.2 GUI Specifications ................................................................... 32 3.2.3 Backend and Frontend specifications ......................................... 33

References ............................................................................................. 34 Annex I: Module I/O description ................................................................ 35


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List of figures Figure 1. The V-model of the Systems Engineering Process [3] ....................... 11 Figure 2: Components of first version of the drilling head and the transportation of cuttings mechanism ............................................................................... 13 Figure 3: The scraper disc is located in the drilling head ................................. 14 Figure 4: An air nozzle provides cooling for the ultrasonic drill bit .................... 14 Figure 5: Transportation of cuttings mechanism conceptual design. ................. 15 Figure 6: Jet pumps could be integrated in the suction house to accelerate the airflow ..................................................................................................... 15 Figure 7: A cone is mounted on the drill head to enable robot retraction. ......... 16 Figure 8: Discrete Movement of the BADGER ................................................ 18 Figure 9: Preliminary design of joint module ................................................. 20 Figure 10: Joint tearing .............................................................................. 20 Figure 11: Standard Stewart Platform .......................................................... 21 Figure 12: Variant Stewart platform with collinear actuators ........................... 21 Figure 13:Preliminary design of the tunnel wall support mechanism ................ 23 Figure 14: Surface Rover Mapping System Architecture ................................. 26 Figure 15: Boustrophedon Motions .............................................................. 27 Figure 16: Computational power is provided by PC(s) on the Central Computer (surface station) and on the underground robot. Time-critical software modules are executed on board the underground robot, less time-critical modules but computationally more intensive, re executed on the Central Computer installed in the central station. The Central Coomputer block is connected to the underground robot block through the router and to rover robot block via bluetooth (Connection A). .......................................................................................................... 29 Figure 17: Computational power is provided by PC(s) on the Central Computer (surface station) and on the underground robot. Time-critical software modules are executed on board the underground robot, less time-critical modules but computationally more intensive, re executed on the Central Computer installed in the central station. The Central Coomputer block is connected to the underground robot block through the router and to rover robot block via bluetooth (Connection A). .......................................................................................................... 30 Figure 18: The computational power is installed on the surface station PC(s). All algorithmic computations are executed there and actuation and operation commands are dispatched directly to PLCs installed on the underground robot modules. The central computer block is connected to the rover robot block via bluetooth (Connection A). .......................................................................... 31 Figure 19: Preliminary schematic of central screen: Navigation and Visualisation screen. .................................................................................................... 32


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List of tables Table 1: BADGER Technical meetings and teleconferences ................................ 9 Table 2: Overall system specifications .......................................................... 12 Table 3: Auger boring drilling head combined with ultrasonic drill bit specifications ............................................................................................................... 16 Table 4: Transportation of cuttings specifications .......................................... 16 Table 5: Clamping mechanism specifications ................................................ 19 Table 6: Propulsion mechanism specifications ............................................... 19 Table 7: Steering mechanism specifications .................................................. 22 Table 8: Tunel wall support specifications ..................................................... 23 Table 9: On-board GPR specifications .......................................................... 24 Table 10: Surface Rover Functionality and Hardware Component Correspondence Table ....................................................................................................... 26 Table 11: Surface Rover Specifications ......................................................... 26


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1. Introduction This document describes overall system functionalities, abilities that the system needs to perform, and specifications of the whole system and each one of its components.

The specifications and functionalities of the system have been elaborated taking into account the user requirements and use cases described in deliverable D1.1 (D1.1.- Use Case analysis and user requirements). Moreover, thanks to the useful and mind-opening technical meetings and varied teleconferences, the functionalities and specifications were studied in depth (Table 1).

Table 1: BADGER Technical meetings and teleconferences

TECHNICAL MEETINGS

January 16-17th 2017 – Kick-off meeting in Leganés (Madrid), Spain.

March 22nd 2017 - Technical meeting in Edinburgh, Scotland, UK.

May 22-23rd 2017 - Drill design concept meeting in Glasgow (between TT and UoG).

June 21st 2017 - Visit to TT Test Field – Lennestadt, Germany.

September 12nd 2017 - System Design and Hardware Development Meeting – London, UK

November 13th - 14th 2017 - System Design, Hardware & Software Development Meeting - Glasgow (Scotland), UK

March 15th 2018 - System design, hardware and software development meeting - Tampere, Finland

May 8th 2018 - System design, hardware and software development meeting – London, UK

TELECONFERENCES

April 21st 2017 – BADGER Preliminary robot system requirements.

May 5th 2017 – BADGER Robot system requirements.

May 29th 2017 – BADGER Robot system requirements.

System specifications have been defined following the methodology described in the MESH (Multimedia semantic syndication for enhanced news services) project.

1.1 Scope of the deliverable This deliverable focuses on the functionalities and specifications of all BADGER subsystems and the way each one is integrated into the modules of the system. In this manner, the scope of this deliverable to describe the overall structure of the BADGER, the basic data required to start the design of each subsystem and some proposals of design to be the starting point of an iterative design process.

1.2 Relation to other deliverables This deliverable is part of the ‘WP1: System specification and system architecture’ which is the foundation of the BADGER project. Due to that, this deliverable establishes the basis of the developments performed in WP2, WP3, and WP4. The


October 2018 10 UC3M

functionalities and specifications presented here have been defined on the basis of the deliverable D1.1’s requirements.

1.3 Deliverable structure This deliverable report is structured into two main parts. In the first part of the deliverable, hardware functionalities and specifications of the whole BADGER system and every component is described. In the second part of the deliverable, software system functionalities and specifications are shown.



2. System model procedure Once the concept of operations has been defined, the next step in order to follow the development of the system should be to specify the requirements and architecture of the whole system. This development process is an example of the V-model of the System Engineering Process.

Figure 1. The V-model of the Systems Engineering Process [3]

It involve early and comprehensive identification of goals, a concept of operations that describes user needs and the operating environment (D1.1 & D1.3), thorough and testable system requirements (D1.2 & D1.4), detailed design (WP2), implementation (WP3, WP4, WP5), rigorous acceptance testing of the implemented system to ensure it meets the stated requirements, system verification (D6.1), measuring its effectiveness in addressing goals, system validation (WP6), on-going operation and maintenance, system upgrades over time, and eventual retirement (WP7 & WP8).

The topic related in this deliverable is a part of the process’ project definition where the requirements of the system are collected by analyzing the user’s needs.

In deliverable 6.1 the system’s functional, interface, performance, data, etc. requirements are described in order to validate and test the system. Therefore, D6.1 serves as a guideline for the design of the system, as an iterative process.

In the system design phase, different possibilities are figured out to accomplish the requirements defined before. Those resolutions are collected in the system’s specification in section 2 of this deliverable.

Furthermore, the architecture design phase is also included in section 2 mentioning the hardware (section 2.1) and software architecture (section 2.2). The basis on selecting the architecture is that it should satisfy the validation and testing requirements.

Later on, the module design phase (detailed design) will be specified in the deliverable 1.4 and in the Work Package 2, in which the system is broken up in smaller units and each of them is explained with the corresponding specifications.



3. Overall System functionalities and specifications The BADGER robot will be modular and heterogeneous, as it shall be composed of different components. This section describes the functionalities and specifications of the overall system and its components. Furthermore, software functionalities and specifications are also explained. Table 2 shows overall system specifications. Table 2: Overall system specifications

Specification Specification Details Comments

Diameter 250 mm Adequate for the BADGER task such as installation of the service pipes, cables, etc.

Length 1500 mm Adequate for the maneuvering in the underground environment

Structure Modular Easy to attach/des-attach modules

Weight As minimum as possible The system should be easily transportable.

Speed As speedy as possible

Power Supply Off-board

On-board

Power supply will be initially located off-board, although on-board power is an option that should be considered.

Water resistance IP68 minimum Adequate for the wet underground conditions

Operating temperature range

-20 to +85 ºC minimum Idem

Soil conditions (1) Clay, sand, and gray

(2) Hard soil conditions

(1) Phase 1: The system will be initially prepared to drill and move in these types of soil.

(2) Phase 2: The system will be tested in hard soil conditions. Phase 1 is requisite for this phase.

Detection of obstacles Frontal and lateral (limited angle of view)

Its enough for the afe navigation

Operating modes Supervised (human in the loop)

Fully automatic – autonomous

In the approach phase, manual & supervised mode and during drilling autonomous onr

Technology Hydraulic, electric, pneumatic or mixed

All of these power technologies are necessary for different devises

In deliverable 6.1, initial trials for the different parts of the system have already been carried out. Each subsystem of the underground robot, surface rover, control hardware and software have been tested separately, configuring the requirements of the whole system.



Moreover, the soil study and soil interaction with the system is another source of requirements for the system, which are specified in detail in deliverable 1.3.

Since the requirements above mentioned are set, the system is designed based on them, and so the specifications will be mentioned in section 2 of this deliverable.

3.1 Hardware functionalities and specifications of the system

3.1.1 Drilling head and transportation of cuttings mechanism functionalities and specifications

The Ultrasonic drill head provides a lower feed force in displaceable soils like sand, gravel or clay. The auger looses the soil and promotes it a bit in the direction of the drill head. The auger could be solid or also made of single hard metal teeth. Figure 2 depicts the first design concept of the drilling head and the transportation of cuttings mechanism.

Ultrasonic drill head

Scraper disc Drive motors

Space for Georadar

(3x on the circumferential) Space for soil

High pressure air supply

Suction hose

auger

Figure 2: Components of first version of the drilling head and the transportation of cuttings mechanism

The scraper disc has several holes on the bevels (Figure 3), which do not pass larger stones, since these would otherwise hinder the subsequent removal. The stones are forced outwards into the surrounding soil by the slope (stones are sifted out).

Depending on the soil conditions, hard metal teeth can be applied to the slope of the scraping disc to loosen the soil. These can be arranged helically in order to promote larger stones to the outside.

On the outside diameter, it is also possible to mount swing-out wings that drill a larger diameter. When the drill head rotates counter-clockwise, they are retracted to retract the drill head through the new printed pipe.



Figure 3: The scraper disc is located in the drilling head

The Ultrasonic drill head sits in the scraping disc. An air nozzle provides cooling for the ultrasonic drill bit (Figure 4). A slip ring contact could be located in or to the right of the housing of the ultrasonic drill bit.

Figure 4: An air nozzle provides cooling for the ultrasonic drill bit

The drive medium has to be selected (hydraulic, electric or pneumatic). The motors transmit the power via pinions to an internal toothing on the drilling shaft. The drill head must be sealed at various points. The appropriate seals must be selected and tested.

The georadar is planned in the area of motors. Three antenna-modules are to be distributed on the circumference. The required space for the antennas has to be considered.

Transport of the cuttings is to be carried out by air transport (Figure 5). This type of transportation should be possible for most soils. Suction via a flushing fluid would also be conceivable, but would require more space and could create difficulties in the support in the soil.

Air nozzle for cooling

Space for a slip ring contact



Figure 5: Transportation of cuttings mechanism conceptual design.

The soil is sucked off via a suction hose. At the end of the suction line is a suction box or suction excavator, which can produce a vacuum of 0.2 to 0.4 bar.

Depending on the diameter and length of the suction hose, jet pumps must also be installed. They are operated with compressed air and accelerate the airflow in the suction hose.

The jet pumps could be integrated in the couplings of the suction hose and are thus distributed over the length of the suction hose (Figure 6). Since each jet pump conveys additional air into the intake manifold, the diameter of the intake manifold must gradually increase slightly step by step when several jet pumps are used one behind the other.

Figure 6: Jet pumps could be integrated in the suction house to accelerate the airflow

The number of nozzles required depends on the material to be sucked, the diameter of the suction hose, the maximum vacuum of the suction box or suction excavator and the nozzles themselves.

The air quantity that is to be extracted from the drill head must be fed through a pressure line. With this construction, the suction is eccentric. For this purpose, it is important that the suction is below the drilling axis. It must therefore be ensured that the housing does not turn slowly in the ground during the drilling process.

Figure 7 depicts a cone used to compact the soil so as to enable a bore hole widther than the BADGER robot. This way, in case of mechanical or electrical failures, the BADGER robot could be retracted in the same bore hole and the cone would be separated from the robot and it would remain inside the bore.

Space for soil

High pressure air supply

Suction hose



Figure 7: A cone is mounted on the drill head to enable robot retraction.

Table 3 and Table 4 show drilling head and transportation of cuttings specifications.

Table 3: Auger boring drilling head combined with ultrasonic drill bit specifications

Specification Specification Details

Drilling methods Auger boring + ultrasonic drill bit

Impact moling + ultrasonic drill bit

Outer diameter 250 mm

Length 450 mm

Weight 40 – 60 kg

Torque 750 – 1000 Nm

Force 500- 750 N

Revolutions 60 rev/min

Energy consumption 7 – 8 Kw

Drilling speed 5 m / hour

Water resistance IP68 minimum

Drilling motion Continuous

Reversible Rotation Required but not continuously

Rotation Drive Electrical or hydraulic

Cooling Water or airflow

Table 4: Transportation of cuttings specifications


Transportation of cuttings technique

Air transport

Suction hose material Flexible material



The drilling head will be tested getting driven by an external hydraulic station and all operating parameters will be measured (lengths and weight, forces and torque, rotational and feed speed, energy consumption and loosen soil capacity for the scraper disc). The goal for this test is to reach the following specifications in order to obtain a successful system.

For the cutting transportations system, simulations and further experiments (check if the suction system works at different feed speeds) are performed with the purpose to determine the required performance of the intake system and to measure the maximum delivery rates for different soil types.

Afterward, a test in the test area of TT will be performed in real soil. Then, the basic drilling functions and the cutting transportation system will be tested. If the results are successful, the system is ready to work. Otherwise, the design phase will be repeated in order to give the system the required specifications for a correct operation.

3.1.2 Propulsion mechanism functionalities and specifications The propulsion mechanism has two main functions:

1. Provide linear motion for the BADGER robot 2. Provide the necessary forward drilling force (Weight on Bit (WOB))

Both the linear motion and forward drilling force are supplied by the same mechanism.

The proposed solution for the propulsion mechanism is a linear actuator contained within each module. The linear actuator is designed to push forward the module in-front. The force required to do this for the drilling head is between 600-800N. The current solution can achieve upwards of 1000N hence the required WOB can be achieved and the drilling can be maintained.

The linear motion is similar to that of a worm. Segments of the BADGER robot move forward while others remain stationary and act as clamps. This combination of moving and clamping segments provides a motion similar to a worms. To achieve a discrete movement pattern the gait in Figure 8 is used. This figure shows the drill head advancing by the length of one extension of a linear actuation. Discrete movement is defined as the overall movement of the system that requires the drilling to stop while the BADGER segments achieve a position ready for the next drill cycle. A method of achieving continuous drilling is being investigated. This method would allow the drill head to constantly move forward.



Figure 8: Discrete Movement of the BADGER

To allow this movement to occur there are two parts to the propulsion system: the linear actuator and the clamp.

During the validation and testing phase (D6.1) it has to be tested whether the selected system is able to perform the defined force and stroke to move the BADGER robot forward.

The tests that will be carried out will involve length and weight measurements and forces tests to check its strength.

3.1.2.1 Linear Actuation A number of methods can provide the linear actuation. At this time, two are being investigated: electromechanical and hydraulic. The electromechanical method is based on electrical linear actuators. This method is well known and easy to control. The required WOB can be delivered from the selected models. As a consequence of other designs, hydraulic fluid could also be present within BADGER. This allows the investigation of using a hydraulic system to provide the linear actuation. At present, both methods can provide the required velocity and WOB. In addition, both methods can be housed within the solid modules of the BADGER, which would result in a length of approximately 450mm each to achieve an extension length of 300mm. With the currently selected method, a maximum speed of 6mm/s can be achieved.

3.1.2.2 Clamp The clamp mechanism provides a point of contact between the walls of the tunnel drilled and BADGER. This system allows the modules to remain stationary while other modules are moving. In addition, the clamp is used to react the torque from the drill head. According to the present estimations, the required torque to be reacted is in the region of 750-1000Nm. The clamp, at this stage, is still in the



conceptual stage. There are currently two designs that are being considered: Feet and Airbag.

The Feet clamp is a module that pushes out a number of feet (placed around the circumference of the module) into the walls of the surrounding material. Once deployed the clamp acts as an anchor point. The advantage of this method is that a simple method of actuation can be used to achieve this (either electromechanical or hydraulic). However further analysis of the design is required before comment can be made on this methods ability to operate as expected.

The Airbag clamp inflates a bag that presses against the walls. The airbag will inflate creating a seal between the module and the walls. This seal will enable the module to react the necessary torques and forces. The basic method is understood and the design is simple. Though there are two disadvantages concerning the Airbag clamp. The first is the requirement to have a source of air to supply the Airbags and the second is the material choice for the bag. Again further analysis of the design is required before comment can be made on this methods ability to operate as expected.

For either method, the crucial parameters are the deployment time, the torque reacted and the force reacted. At this time the numbers available are a torque of 750-1000Nm to be reacted and a linear force of 600-800N to be reacted.

First tests will be carried on checking the components into clay. After further tests the clamping system will be checked whether it is adequate or not, in which case new alternatives will be developed.

Those tests will consist on ensuring that the system inflates and deflates when instructed, diameter measurements after inflation/deflation, tests to withstand some torque and force, and time measurements for inflation/deflation.

Table 5: Clamping mechanism specifications


Diameter after inflation 300 mm

Torque reaction 750-1000 Nm

Force reaction 600-800 N

3.1.2.3 Overall System The basic three Module BADGER system will consist of two linear actuation systems and three clamps. The actuators and clamps work as shown in Figure 8. With respect to the current design of using 300mm electromechanical linear actuators. Table 6 shows the propulsion mechanism specifications.

There are currently no specifications for the clamp. At this stage two redundant propulsion mechanisms are being considered. These modules would allow recovery from a number of failures and faults.

Table 6: Propulsion mechanism specifications


Max. WOB and linear force 1000 N

Max. speed 6 mm/s



Max. solid module 450 mm

Drilling torque to react 750-100 Nm

Actuator Electromechanical

3.1.3 Steering mechanism functionalities and specifications With this first concept of combined discrete push movements with various clamping modules, the joint module must endure the torque created by the drill head.

This first version of joint, made of 3 independent cylinders will be able, in theory, to support this axial torque (Figure 9). Nevertheless, in practice, and because of the very high torque that can be provided by the drill (up to 1000Nm), the three cylinders would suffer from flexion stresses and strains, while cylinders have to work only in compression/extension. After a while of such operation, it could result some joint failures and the robot could be out of service (Figure 10).

DRILL COUNTER TORQUE

Figure 9: Preliminary design of joint module

JOINT FAILURE

Figure 10: Joint tearing

A solution to resolve this issue is to replace each joint module by a Stewart platform. Nevertheless, each module must include not 3, but 6 independent cylinders.



Figure 11: Standard Stewart Platform

Figure 12: Variant Stewart platform with collinear actuators

Advantages:

Each actuator is working in compression/extension No fail 6 DOF and possibility to displace the centers of rotation

Disadvantages:

Heavier More Expensive More complex



During the validation and testing phase it has to be tested whether the selected system is able to perform the defined some radius and angle to move the BADGER robot. Tests will involve tilt and strength measurements.

Table 7: Steering mechanism specifications


Steering radius 10 m

Steering angle 4 º

3.1.4 Tunnel wall support functionalities and specifications In order to have stable and secure conditions to the robot movement along the planned path, we need to ensure that the constructed tunnel will not collapse.

Clamping forces, ultrasonic vibrations of the drill head and unstable environment lead to the requirement for the enablement of the BADGER system with a wall support mechanism.

Another fact to have in mind is that wall support needs to have enough strength to resist clamping forces used for the robot movement, the torque produced by drilling and the axial forces generated with the robot movement.

The tunnel size is needed to be bigger than the maximum diameter of the robot so, the cavity produced by the hammer drill has to be compacted just before the drill head. This is mandatory to ensure any backward movement.

3.1.4.1 Wall support options. There is a lot of commercial resin-based and water-based products used for soil stabilization. Such products are used for outdoor pavement stabilization1.

Resin-based soil stabilizers.

Advantages:

Very strong and durable Water resistant

Disadvantages:

Resin needs time to cure Not easy to apply

Water- based soil stabilizer

Advantages:

Strength enough to this application Water resistant. Easy to apply with a sprayer Fast drying, only needs to evaporate.

Disadvantages: Needs that the soil is mixed and compacted with it.

The design of a wall support spraying device just before the drill head to mix a water-based product with the soil as it is being compacted seems the most plausible solution.

1 http://www.polypavement.com/index.php



Figure 13 depicts a preliminary design of the tunnel wall support mechanism towards reaching the final solution.

Figure 13:Preliminary design of the tunnel wall support mechanism

Since the wall support system consist on the pump and spraying mechanism and the material used, the requirements for the system while be based on 2 phases of experiments (D6.1).

The first phase will consist on the material testing, which has to be selected and will be deposed on the tunnel surface by the pump and spraying system.

The specifications for the material will be a result of the selected material in consideration of environmental, processing and price aspects.

The test performed to find out the viable compositions will be carried on different conditions concerning temperature, humidity and soil (D1.3).

The second phase of the system is the pump and spraying mechanism which must be selected in consideration with the characteristic of the material selected and the ground.

The integration with both phases will be the basis for the required specifications of the system.

The system will then be checked with the following tests: in order to check the roundness of the tunnel, a section of 250mm will be pushed through the tunnel; for the tunnel to avoid collapse, forces supported will be measured on fresh material at a certain depth; for checking the humidity resistance

Table 8 shows tunnel wall support general specifications.

Table 8: Tunel wall support specifications


Tunnel diameter after 3d printing

>max. diameter of BADGER system

Tunnel wall support strength

It should be strong enough to resist torques and forces generated during the drilling

Feed rate Should be synchronized with the forward movement of the robot



Durability The constructed tunnel wall support should be as durable as possible

Faster Drying The material should dry fast

Water resistance The chosen material should be water resistant

3.1.5 On-board GPR functionalities and specifications

3.1.5.1 Detection The primary function of the GPR onboard the robot is to detect objects that are likely to affect the progress of the drilling, with the aim of avoiding damages to any adjacent objects during this operation. Table 9 shows the on-board GPR specifications. With respect to the position of the robot, this can be set as requirement on the detection range in the bore-sight (straight ahead) and azimuth (sideways) directions.

In general, the shape of buried objects may be of a linear or of an amorphous nature, and different requirements apply to the minimum required size at which they must be detected, regardless of whether they are composed of conducting or non-conducting material.

3.1.5.2 Resolution and accuracy Preferably, the GPR shall be able to determine the presence of multiple objects when they are separated by more than 300 mm up to 0.5 m.

It is important for the operator to know where the detected object is located relative to the robot. It needs to be able to determine whether the detected object poses any problem for the success of the bore or any hazard to the operations.

3.1.5.3 Operational The GPR shall support:

o System settings / adjustments via Laptop / PC must be possible prior to use

o An interface to transfer data to a Laptop / PC in order to create an alarm event report

o A communication protocol that ensures there is permanent communication between down-hole electronics and the operator at the surface

o System auto-diagnosis. o Data logging (logging device: Laptop/SBC)

The specification for the GPR onboard the robot will be tested in D6.1 by several tests regarding each of its components.

For the GPR module specifications to be determined, a single module will be tested by a sandbox test will be performed to check some parameters such as SNR, bandwidth, time jitter, amplitude jitter and noise level. Another test will be carried on the test pit where several objects of different materials are buried. This will lead to the specifications about the capability of detection.

Concerning the Radar control unit, it will be connected to a specific testbed in order to check the specifications about the required input and output signal.

Table 9: On-board GPR specifications




Antennas size (Transmitter or Receiver)

200x90x50 mm

Configuration of the antennas 3 Transmitter-receiver pairs

Weight <2 kg

Power consumption <20 W

Operating temperature range -20 - +50 °C

Water resistance IP65

Frequency of operation 600MHz

Transmitted power <1mW

Sensitivity of the receiver 70 dB

Detection range Bore-sight Direction

Minimum 1 m

Preferred 2 m

Azimuth Direction

Minimum 1 m

Preferred 2 m

Minimum size to detect objects

Linearly Shaped Objects

50 mm across the longest cross section up to 0.5m from the GPR

300 mm across the longest cross section up to 1m from the GPR

Target detection percentage in absorptive soil conditions

Minimum 95% of all real targets

Resolution (min. distance between objects to be located)

More than 300 mm up to 0.5 m

Accuracy (max. error tolerance of the position in axial and radial direction)

50 mm up to 0.50 m distance from the robot

Less than 10% of the distance where the object is located

3.1.6 Surface rover functionalities and specifications The surface rover of BADGER will be responsible for the construction of an initial 3D metric map of the operational area and for providing assistance in the localization of the underground robot.

The rover will navigate above the underground robot’s operational area and as shown in Figure 14, it will use a stereo camera for visual odometry and surface mapping (enabling its own localization), as well as a surface GPR for the detection of underground objects and utilities. By registering the surface GPR measurements on the basis of the rover’s localization outcome, the 3D subsurface map will be developed. This map will be the initial representation of the underground robot’s operational environment, which will be later on, during the



robot’s operation, refined through underground SLAM. During the robot’s operation, the surface rover will be responsible, either through its GPR or further sensors (e.g. beacons) to facilitate the localization of the underground robot.

The above tasks will be realized by five functionalities and their corresponding hardware components (Table 10) as described in the following subsections.

Figure 14: Surface Rover Mapping System Architecture

Table 10: Surface Rover Functionality and Hardware Component Correspondence Table

Functionality Stereo Camera

GPS GPR Antenna-Beacon Pair

3D Surface Mapping ✓

Surface Rover Localization ✓ ✓

Surface Rover Navigation ✓ ✓

3D Subsurface Mapping ✓

Underground Robot Localization

✓ ✓

These hardware components will be installed on a surface rover with the specifications showed in Table 11.

Table 11: Surface Rover Specifications


Dimensions 731 x 578 x 440 mm

Weight 65 Kg

Load capacity 65 Kg

Speed 3 m/s

Water resistance IP54

Operating temperature range -20 - +50 ºC

3.1.6.1 3D Surface Mapping One of the roles of the surface rover is to construct an initial rough 3D metric map of the surface above the underground operational area, which will enable the surface rover to navigate and cover the surface of the operating area while recording GPR data. For this purpose, the surface rover will utilize a simultaneous localization and mapping (SLAM) algorithm that will produce a 3D metric map of the surface of the operating region, using 3D pointclouds produced from stereo camera image pairs (utilizing the rover’s on-board stereo camera).



3.1.6.2 Surface Rover Localization The surface rover will utilize visual odometry techniques, which can be integrated in the aforementioned SLAM algorithm. If needed, the fusion of the VO outcome with wheel odometry data could be considered so as to provide more accurate localization, while GPS can be also utilized to obtain georeferenced localization. The accurate localization of the surface rover is crucial for both the production of consistent 3D surface map and for the progressive registration of GPR data that will be used for the production of the initial rough 3D subsurface metric map. In addition, accurate localization is required for robust autonomous navigation behavior of the surface rover in both the initial mapping operation and the underground robot tracking.

3.1.6.3 Navigation For the complete coverage and mapping of the operational area, the surface rover will support both autonomous and teleoperated operation. In both cases the rover must cover the whole surface of the operational area using boustrophedon motions (Figure 15) when it is feasible considering ground traversability constraints. In the autonomous mode, the primary target will be augmented teleoperation, where the human operator will be receiving constant path correction assistance. Further extensions to the autonomous mode could be considered, by employing for instance an autonomous coverage algorithm that performs target selection while considering the desired boustrophedon motion pattern, however in such case there could be increased navigation errors.

Figure 15: Boustrophedon Motions

3.1.6.4 3D Subsurface Mapping The surface rover will be responsible for the construction of the initial rough 3D subsurface metric map of the operational area, where the underground robot will work. This will be accomplished by registering the GPR data obtained by the surface GPR with the localization estimation of the surface rover. GPR data will be obtained in the form of B-scans, which consist of a collection of A-scans measured along the direction of motion of the GPR. By processing the B-scans, the surface rover will extract information about the ground, as well as position, shape and scale information about buried objects and utilities. The 3D subsurface metric map will be used for the initial path planning of the underground robot. This map is expected to be further enhanced through GPR measurements and corresponding underground robot localization, both taken from the subsurface robot.



3.1.6.5 Localization of the Underground Robot Due to the limited localization information sources that are available for subsurface operations, the surface rover will assist in the localization of the underground robot by tracking it from above ground. This will be realized through a walk-over technique, by utilizing either the surface GPR or an antenna-beacon pair (signal emitted by a beacon mounted on the underground robot). More specifically, the surface rover will navigate on the surface over the underground robot when feasible and provide it with additional localization information.

3.2 Software functionalities and specifications The BADGER software will be implemented using ROS Kinetic on Ubuntu 16.04 Linux OS. The ROS nodes will be programmed in C++ or Python, or both. The integrated software will execute a number of processes connected in a peer-to-peer topology, according to a distributed-network computing paradigm. The partners opted for this topology because it enables the simultaneous execution of the basic BADGER software modules, such as navigation, perception, sensing, actuation and system supervision modules. Heavy computational load due to execution of SLAM, object segmentation and 3D world reconstruction algorithms might demand the use of more than one computers equipped with powerful GPUs. The actual hardware architecture (number of PCs, GPUs etc.) will be specified after the major software components will have been built, integrated and tested.

3.2.1 Preliminary block diagram representation of SW architecture

Two software architectures will be investigated. The first architecture assumes that at least one PC will be installed on the surface station and at least one on the underground BADGER robot. Hence, software modules are distributed between the surface station and the on-board PCs. Computationally intensive code runs on the surface station, where there are no space restrictions, and more than one PCs and GPUs can be accommodated. Less computationally demanding code runs on the PC(s) installed on the underground robot. The second architecture assumes that for economy of space all PCs are installed on the surface station and that the underground robot is equipped only with PLCs and microcontrollers. In this case, all important software modules run on the surface station and control commands are transmitted to the robot through Ethernet communication. Figure 16 and Figure 18 present preliminary indicative designs of these two architectures.



Figure 16: Computational power is provided by PC(s) on the Central Computer (surface station) and on the underground robot. Time-critical software modules are executed on board the underground robot, less time-critical modules but computationally more intensive, re executed on the Central Computer installed in the central station. The Central Coomputer block is connected to the underground robot block through the router and to rover robot block via bluetooth (Connection A).



Figure 17: Computational power is provided by PC(s) on the Central Computer (surface station) and on the underground robot. Time-critical software modules are executed on board the underground robot, less time-critical modules but computationally more intensive, re executed on the Central Computer installed in the central station. The Central Coomputer block is connected to the underground robot block through the router and to rover robot block via bluetooth (Connection A).



Figure 18: The computational power is installed on the surface station PC(s). All algorithmic computations are executed there and actuation and operation commands are dispatched directly to PLCs installed on the underground robot modules. The central computer block is connected to the rover robot block via bluetooth (Connection A).



3.2.1.1 Preliminary Description of SW modules The major software modules presented in Figure 16 and Figure 18 are described in the Annex, in terms of Actions, Inputs and Outputs.

3.2.2 GUI Specifications Partner TT, based on their long-standing experience with end-users at the working site, has specified the expected content of the GUI. The GUI will comprise a central screen, which will be supported by four other complementary screens. The following paragraphs provide brief description for each screen.

3.2.2.1 Screen 1 (central screen): Navigation and Visualization The central screen shows the on-line monitoring of the BADGER robot operation. Its contents are:

• Navigation monitoring

o Top view and side view

• Presentation of underground utilities (based on GPR image view)

o Top view and side view

• Performance data

• Health data

• 3D visualization of the process

The content, (apart from the 3D visualization), is schematically depicted in Figure 19.

Figure 19: Preliminary schematic of central screen: Navigation and Visualisation screen.

3.2.2.2 Screen 2: Robot Planning and Configuration Screen It provides the tools for designing the Path of the BADGER robot:

• Motion Planning in 3D

o Top view of path

o Side view of path

o Graphical modality where the user specifies the entrance and exit points and if needed additional intermediate waypoints/constraints that should be subjected on the path. The motion planning algorithm then generates the path and the trajectory.



3.2.2.3 Screen 3: Manual Operation Screen When Manual Operation is selected, a new screen appears which combines a Manual Control pane together with the Navigation and Visualization pane. The user is able to adjust the path of the robot and at the same visualize the path adjustments on the visualization pane. The Manual Motion control screen contains:

• Virtual slider buttons for adjusting robot speed and thrust

• Virtual buttons for activation/de-activation of functionalities

• Connectivity with joysticks

o Left joystick: Activate and control the locomotive propulsion mechanism backwards and forwards

o Right joystick: Steering of the robot (up/down/left/right)

3.2.2.4 Screen 4: Control of 3D Printer This screen depicts:

• Operating status of the 3D printer

• Cartridge status

• Settings of the 3D printer

3.2.2.5 Screen 5: Rover Configuration and Navigation This screen depicts:

• The operating status of the rover

• The desired trajectory

• Actual trajectory

• Virtual buttons for activating/deactivating functionalities

• Pane for configuration and programming the rover

3.2.3 Backend and Frontend specifications

3.2.3.1 Backend The BADGER consortium will employ the MariaDB open database software as a backend solution. It is an enhanced, drop-in replacement for MySQL. MariaDB is used because it is fast, scalable and robust, with a rich ecosystem of storage engines, plugins and many other tools make it very versatile for a wide variety of use cases. It is developed as open source software and as a relational database it provides an SQL interface for accessing data. The latest versions of MariaDB also include GIS and JSON features, which facilitates the integration of the database with ROS nodes.

3.2.3.2 Frontend The frontend solution will be based on a Webserver implemented using JSON and PhP.7 on an Apache server 2.4.28. The webserver will employ WebSocket protocol (TCP based) for faster operation. The partners have verified that JSON can be interfaced with ROS node using ROSBridge libraries. Rosbridge provides a JSON API to ROS functionality for non-ROS programs. There are a variety of front ends that interface with ROSBridge, including a WebSocket server for web browsers to interact with.



References [1] BADGER Grant Agreement Annex I – “Description of Action” (DoA)

[2] MESH Deliverable D6.3 - User and System Requirements

[3] Clarus Concept of Operations. Publication No. FHWA-JPO-05-072, Federal Highway Administration (FHWA), 2005



Annex I: Module I/O description BADGER::Supervision_ Decision Actions:

Implements supervision and decision unit for the BADGER system Communication between GUI and software modules Communication between host computer and other computers Transmit control packets {control commands} receives acknowledgments Monitors the status of each process {success, fail, running}

Inputs [from GUI] Outputs Application description [XML file] Application or Tasks ID

Application related parameters Control commands {Start, Terminate, Pause}

Control signals

BADGER::FSM Actions:

Implementation of Finite State Machine Model the BADGER operation as a set of finite states Dictate the state transition according to input (events) from supervision module

and from controller Inputs Outputs Control signals [from Supervision module] State transition Task execution status {success, running, fail} BADGER::Motion Planning Actions:

Real-time generation of operational space trajectories for the first module (drill head module)

Inputs Outputs Desired path: waypoints {(x,y,z), (roll,pitch,yaw)} [from GUI]

Desired thrust Desired steering force

[to Inverse Simulation module]

BADGER::Inverse_Simulation Actions:

It generates actuators’ commands Inputs Outputs

Desired propulsion force and drill head RPM

Desired steering force [from Motion planning module]

Force and torque commands of the actuators

BADGER::Hardware_Controllers {multiple modules: Drill head controller, Steering controller, Thrust controller} Actions:

It generates servo (or servovalve) commands Inputs Outputs

Force and torque commands of the actuators [from Inverse simulation module]

PWM commands [to hardware servo drivers]

BADGER::Object_Localisation Actions:

Object identification Object segmentation Object localization

Inputs [from GPR processing unit] Outputs [to world model]



Point cloud Object ID Representation of object 3D geometry Position and orientation of the object

BADGER::GPR_Processing Actions:

- Generates point cloud data Inputs [from GPR hardware] Outputs [to Object localization]

Radar raw data Point cloud

BADGER::SLAM Actions:

- Performs SLAM of the underground robot Inputs [from GPR hardware] Outputs [to Object localization]

Estimate of BADGER current position [from BADGER localization (surface rover)] Landmark features [from World model]

Updated localization Updated landmark

ROVER::Motion_Tracking_Controller Actions:

- Motion tracking of the rover robot while it scans the surface Inputs Outputs

- Desired path (x,y,θ) [from GUI] - Current state (x,y,θ) [from

localization]

Motors velocity [To motor drivers]

ROVER::Localisation

Actions: - Estimation of BADGER location (x,y,z)

Inputs Outputs - GPR processed signal [from GPR

processing module] Motors velocity [To motor drivers]

ROVER::GPR_Processing Actions:

- Generates point cloud data Inputs [from GPR hardware] Outputs [to Object localization]

Radar raw data Point cloud

ROVER::Surface_Mapping Actions:

- Generates 2D map of the surface - Detects and estimates landmarks

Inputs [from RTAB] Outputs [Localization] RTAB map Annotated surface mapping

ROVER::VO-based RTAB map Actions:

- RGB-D Graph-Based SLAM approach based on an incremental loop closure detector

Inputs [from on-board cameras] Outputs [Localization] RGB-D or stereo-camera image Updated RTAB map locations

Documents

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