Tactile Sensing: New Directions, New Challenges

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Tactile Sensing New Directions, New Challenges

• By
• Ramya Bandaru
• 00544366

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Tactile sensing

• A form of sensing that can measure given
  properties of an object through physical contact
  between the sensor and the object.
• The forces and torques experienced through points
  of contact with a surface are very important for
  manipulation and grasping tasks.
• Most of the tactile sensing deals with surface or
  skin like sensors and so does not concern force
  or torque sensing.

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Development in 1970s

• Great deal of robotics activity but little
  research on tactile sensing.
• Good ideas were put forward but devices were
  primitive.

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1980s

• Period of growth and exploration.
• A great variety of device designs, transduction
  methods and sensing physics was examined in this
  period.
• Successful devices were built that could detect
  object properties.
• Importance to device centered approach and
  hardly any emphasis on task centered approach.

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Work of Leon Harmon

• Survey on the determination of requirements for
  tactile sensing in industrial tasks.
• Devised desirable performance specifications

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Drawbacks of Harmons survey

• Survey was speculative and many of his
  conclusions appear optimistic.
• Much of the analysis focused on factory based
  robotics and automation.

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Industrial tactile sensors
Touch sensor for micromanipulation with pipette
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Failure to penetrate into industrial applications

• Basic specifications such as that of Harmon could
  not be achieved.
• Performance problems made them unsuitable for
  simplest tasks.
• Laboratory prototypes were unreliable and
  difficult to reproduce.

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1990s

• Continued growth of research in tactile sensing.
• Notable developments
• Better engineering and new materials
• Increased understanding of the role of sensors
• Improved dexterous robot hands
• New medical applications
• Shift in area of research from factory based
  robotics towards the world of natural systems.

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New opportunities for tactile sensing in robotics

• Difficulty levels for robotic tasks can be
  distinguished as
• - irregularities in objects to be handled
• - disorder in the working environment
• - both occurring together
• Examples Food processing in a factory, under
  water repair work, and surgical operations,
  respectively.
• Contact events are more significant in these
  areas
• Tactile sensing may offer solutions that cannot
  be matched by other sensing modalities, such as
  vision.

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Three main application areas as identified by
Lee and Nicholls (1999)

• Surgery and medicine
• Health care and service robots
• Agriculture and food processing

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Surgery and medicine

• Surgery is a visual and tactile experience
• Limitations on the surgeons sensory abilities
  -undesirable.
• Tactile sensors in minimal invasive surgeries,
  palpation.
• Scope for new sensing instruments
• Need for restoring full freedom of manipulation
  during remote procedures.

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Prototype palpation instruments
The motions of the surgeon's finger are
transmitted to the tactile sensor on the
instrument tip through a cable drive mechanism. 
Tactile sensations measured with the sensor are
recreated on the surgeon's fingertip with the
tactile shape display.
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Health care and service robots

• Demands for health care and support of the
  elderly.
• Robotics in this area will have demanding,
  specific and unusual requirements.
• Dexterous manipulators will be important here.
• Big challenge low cost design and engineering
  of such systems.

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Another concern

• Unique nature of each individual environment.
• Predefined functions will have a limited role
• Each system needs to be customized
• High level of human friendliness, compatibility,
  acceptance.
• High levels of safety, reliability
• Any failure must carry low risk for the user.

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Service robots using tactile sensors
RI-MAN the worlds first robot designed for
lifting and carrying humans.
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Agriculture and food processing

• These industries are automated but do not employ
  robotic or tactile sensing.
• Fully automated factories have better environment
  for food processing but hazardous for humans and
  hence require robotic handling systems.

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• Robotic grippers have to be adaptive and
  automatically accommodate size and shape variation

A cooperative robot with visual and tactile
sensing
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Detects deformations and vibrations during the
tactile contact with an object
Robot hand holding egg
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Conclusions

• Tactile sensing has matured considerably
• General shift of emphasis
• Contact tasks in unstructured environments.
• Dexterous manipulation
• New applications in the living world