Artificial Intelligence in Underwater
Manipulation Peter Kampmann
Frank Kirchner
DFKI Bremen & Universität Bremen
Robotics Innovation Center
Director: Prof. Dr. Frank Kirchner
www.dfki.de/robotics
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Underwater Manipulators
Orion 7P, Schilling Robotics
Predator, Kraft Telerobotics
Underwater Electric Arm, Robotnik
Lift capacity: 250 Kg Grip force: 4448 N Sensors: Encoders
Lift capacity: 25 Kg Sensors: Encoders
Lift capacity: 227 Kg Grip force: 1334 N Sensors: Encoders Force Feedback
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Underwater Manipulators
• Examples for underwater manipulation tasks
Images courtesy of ROPOS ROV, Neptune Canada team
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Underwater Manipulators
• Challenges while working with manipulators under water
Missing 3D Information
Turbulences on your operating vessel
Turbulences acting on the ROV/AUV
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The CManipulator Project
Scene-Camera
High resolution Digital-Videocamera
Dynamic
controllable
Lighting
Primary-
Manipulator
ORION 7P
(hydraulic)
ROV Movement Simulation
Manipulation-Objects
Secundary-Manipulator:
SubAtlantic 123+2
(electric) Wrist-Camera
Digital-Videocameras
Scene-Camera
High resolution Digital-Videocamera
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CManipulator working principle
• Computer control system is connected between master arm
and slave arm
Enabling the operator to take over from computer control at
any time
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CManipulator contributions
• Development of a cascaded position/speed controller on
the Orion 7P manipulator
• Realisation of cartesic movements using fast kinematics in
closed analytic form
• Underwater image processing
Detection of predefined objects (e.g. transponders)
Visual servoing approaches
Visually guided pick and place tasks
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CManipulator Kinematic
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CManipulator Pick & Place
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CManipulator Position Control
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CManipulator – Position control
Disturbances of 2 cm/sec
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CManipulator – Position control
Disturbances of 5 cm/sec
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CManipulator Plug Handling
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Further obstacles in underwater manipulation
• Low visibility
• No force feedback on the gripper
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Working in Deep Sea
• Interest of building construction sites in deep sea increases
(Source: Marine Mineral Society)
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Working in Deep Sea
Divers cannot reach the depths where current construction sites are build
and have to be maintained
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Working in Deep Sea
„Working there is like doing an operation at the open heart in 1500 m depth.
In complete darkness, using robot-controlled miniature submarines.“
Lamar McKay, BP America President (Berliner Tagesspiegel, 10th of May 2010)
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Fine-Manipulation in Deep-Sea
• Development of a gripper system for deep-sea
environments that is capable of performing form- and force-
closed manipulation tasks having tactile feedback.
The SeeGrip Manipulation System
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The SeeGrip project
• Development of a hydraulic gripper system with a sense of
touch
Challenges
► Selection of applicable sensor measurement principles
► Finding suitable actuators for the gripper system
► Secure electronics against ambient pressure
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SeeGrip - Sensors
• Tactile Sensing
Sense as much different modalities of touch as possible in
order to gain information on
► Material properties (Texture, Hardness, Heat transfer)
► Geometric properties
► Weight (Absolute, Distribution)
Sensors measuring touch mostly need to be in direct contact
with the object that has to be explored
► Surface area becomes crowded
The water column has effect on the sensor selection
► Need to achieve highest accuracy for force induced by touch
► Measuring ambient pressure is not desirable
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SeeGrip Sensors
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SeeGrip Sensors – Strain gauge
• Strain gauge sensors have
been widely used in
underwater sensor setups.
• Measurement principle
based on deformation of
cantilever resulting in an
deformation of the strain
gauge sensor.
• Ambient pressure keeps
sensor in static condition
ATI Nano 25 FT-Sensor
ROV Sensor setup from [1]
[1] Force Control Test Bench for Underwater Vehicle-Manipulator System Applications
Sylvain Lemieux, Julien Beaudry und Michel Blain, 32nd Annual Conference on IEEE Industrial Electronics 2006
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SeeGrip Sensors - Piezoelectric
• Piezoelectric materials are
also widely used in
underwater applications
Sonars
Bottom Pressure
Recorders
• Signal response of
piezoelectric sensors is
dynamical
Ambient pressure leads to
static condition while not
activated
Customized piezoelectric sensorfield
for the SeeGrip project
Bottom pressure recorder using
piezoelectric transducers. [2]
[2] Image from Neptune Canada Team
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SeeGrip Sensors – Fiber optic
• Fiber optic measurement
principles that measure
cavities have not been used
in underwater applications
so far
• Foam is floated with
transparent fluid
Similar behavior as natural
sponges which live in up to
5000m
• Signal output not affected by
water column
Working principle of KINOTEX Sensor
KINOTEX Sensor idented at 600 bar
ambient pressure at DFKI RIC Bremen
Towards a fine manipulation system with tactile feedback for deep-sea environments,
Peter Kampmann and Frank Kirchner, Robotics and Autonomous Systems, to appear
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SeeGrip Sensors – Fiber optic
Towards a fine manipulation system with tactile feedback for deep-sea environments,
Peter Kampmann and Frank Kirchner, Robotics and Autonomous Systems, to appear
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SeeGrip Sensors – Fiber optic
Towards a fine manipulation system with tactile feedback for deep-sea environments,
Peter Kampmann and Frank Kirchner, Robotics and Autonomous Systems, to appear
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SeeGrip Sensors - Multimodality
• Combining strength of each
measurement principle
• Strain gauge for
quantitative forces using
intrinsic tactile sensing
• Piezoelectric sensors for
texture, slippage and
dynamic impacts
• Fiber optic sensor for
geometry detection, force
distribution
Combining static and dynamic force
measurement at the same contact area.
Completely setup prototype of
multimodal tactile unit A Tactile Sensing System for Underwater Manipulators,
Peter Kampmann and Frank Kirchner,
Workshop on Advances in Tactile Sensing held in conjuncion with the
HRI 2012 conference, Boston, USA
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SeeGrip Sensors - Summary
Total sensors per finger:
648 Fiber optic sensels
40 Piezoelectric sensels
6 Strain gauges
2082 tactile sensing units
+ 25 Proprioceptive Sensors
On the complete system
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SeeGrip Actuation
• Compatibility to existing deep-sea manipulators, choose
hydraulics as actuation system
• Hydraulic modules are commonly used for applying high
forces
Project goal is to design a gripper for fine-manipulation
High forces are not needed
• Goal: Find hydraulic actuators that are small in their
dimensions in order to be integrated into the gripper system
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SeeGrip Actuaction
Graphics are to scale
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SeeGrip Actuation
• Chose dosing valve for
actuating the system
• Setup using two valves on
inlet and outlet of hydraulic
circuit
• Pretensioning chambers of
the hydraulic circuit allows
for a variable compliance in
the manipulator
Hydraulic circuit schematic
A small-scake actuator with passive compliance for
a fine-manipulation deep-sea manipulator,
Johannes Lemburg, Peter Kampmann and Frank Kirchner,
Ocean‘s 2011, Kona, USA
Hydraulic system in action
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SeeGrip Electronics
• The ambient pressure
exposes a lot of mechanical
stress to electronics
underwater
• Until now, two different
possibilites exist
Housing
Pressure Tolerance
• Enhanced this by a hybrid
approach, saving integration
space and manufacturing
costs
Hybrid Pressure-Tolerant Electronics,
Peter Kampmann, Johannes Lemburg, Hendrik Hanff and Frank Kirchner,
Ocean‘s 2012, Virginia, USA
Electrolytic capacitor exposed to deep-sea
ambient pressure conditions
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SeeGrip Electronics
• Hybrid pressure tolerance
Shielding components that
are affected by ambient
pressure
Other components are
exposed to water column
• Pressue tolerant modules
SMD parts are manufactured
without gas inclusion
Oscillators often have
nitrogen included
► Switch to MEMS Oscillators
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SeeGrip Electronics - Summary
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Summary
• Handling tasks in deep-sea environments will increase in
complexity within the next years
Divers cannot work in the depths where current offshore
construction sites are built
The used technology will increase in complexity which leads
to more complex setup and maintenance tasks
• Underwater manipulation still has a lot of potential to gain
from robotics on land or in space
Thank you!
DFKI Bremen & Universität Bremen
Robotics Innovation Center
Director: Prof. Dr. Frank Kirchner
www.dfki.de/robotics
