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Whiskered robots: from Whiskerbot toward SCRATCHbot
Many rodents have the ability to actively move their facial whiskers (vibrissae) in a rhythmic sweeping pattern as they explore their environment. This active movement, combined with the exquisite tactile sensitivity of each whisker, gives the rodents a superior sensory advantage in occupying and hunting in environments where visually dominant predators perform badly. Conventional robotic proximity sensors and vision based navigation strategies also perform badly in such environments which has significant implications for potential rescue or recovery robots operating in natural disaster sites or collapsed mines. By taking biological inspiration from the rodents to design and build an active artificial whisker sensor system we also have the opportunity to work collaboratively with biologists and neuroscientists to help further our understanding of the bio-mechanical and robust neural mechanisms behind tactile sensation and perception.
All the robots described below were designed in close collaboration with neuroscientists from the Active Touch Laboratory at Sheffield University, primarily as research tools to study the whiskers of a rat and the functional architecture of the mammalian brain. These are justifications for the robots’ development. The technology demonstrated on the robot, namely the active touch sense and the ability to explore an environment in a non-visual way, could be exploited further, and rescue operations is one possible application domain. Other applications which may benefit from this "technology" could be in the inspection of large fluid filled tanks found in the nuclear industry or inspection of pipes or conduits filled with dirty fluids or for textiles quality inspection. However, the point here is that none of the robots were specifically designed for any of these application domains.
In 2003 we began a collaborative project with the Adaptive Behaviour Research Group at the University of Sheffield. The study, funded by EPSRC, and referred to as Whiskerbot, investigated a bio-mimetic artificial whisker system which could provide a novel form of robot tactile sensor capable of texture discrimination and object recognition. The project involved mounting an array of actively-controlled artificial whiskers on a mobile robot to generate input for computational models of neural sensori-motor pathways in the rat brain. Video of Whiskerbot finding 2 pens
The work undertaken in the Whiskerbot project has been developed further as part of a large EU framework6 funded project called ICEA, or Integrating Cognition, Emotion and Autonomy (ICEA project website). Following on from Whiskerbot, therefore, a group of researchers from the University of Sheffield and the Bristol Robotics Lab, a partnership between the University of the West of England and the University of Bristol, based in the Bristol Business Park, have gone on to develop the SCRATCHbot (Spatial Cognition and Representation through Active TouCH bot), which is a significant milestone in the pan-European ICEA project. As part of this project Professor Tony Prescott, from the University of Sheffield’s Department of Psychology, is working with the Bristol Robotics Lab to design innovative artificial touch technologies for robots that will also help us understand how the brain controls the movement of the sensory systems.
The new technology has been inspired by the use of touch in the animal kingdom. In nocturnal creatures, or those that inhabit poorly-lit places, this physical sense is widely preferred to vision as a primary means of discovering the world. Rats are especially effective at exploring their environments using their whiskers. They are able to accurately determine the position, shape and texture of objects using precise rhythmic sweeping movements of their whiskers, make rapid accurate decisions about objects, and then use the information to build environmental maps.
Click the above images to play videos
SCRATCHbot has a number of improvements over the Whiskerbot platform, namely; the active whisker array consists of 18 rather than 6 whiskers. There is an additional non-actuated micro-vibrissae array located on the "nose". Tthe "head" is connected to the body by a 3 degrees of freedom neck, and the body is driven by 3 independently steerable motor drive units. These improvements have so far allowed us to model more closely the sensori-motor coordination of the active whisker array (brain stem) and spatial orientation behaviour (superior collicular inspired) to move the micro-vibrissae array to contact points in three dimensional space. We also plan to integrate the whisker sensory information with a hippocampal model (developed by other ICEA consortium members) to investigate how a rat may use it's whiskers to navigate through the environment. Video of SCRATCHbot exploring. More Details...
![[Etruscan shrew]](/images/160/shrew_square.jpg)
While vision supplies information about distant objects, touch is invaluable in sensing the nearby environment. However, in designing intelligent, life-like machines, such as robots, the touch modality has been largely overlooked. Current systems make only limited use of tactile sensors for simple tasks such as detecting physical contact. Biology, by contrast, reveals an abundant use of tactile sensing in the animal kingdom. Indeed, in nocturnal creatures, or those that inhabit poorly-lit places, touch is widely preferred to vision as a primary means of discovering the world. The tactile senses of many mammals are built around arrays of facial hairs known as "whiskers" or "vibrissae". In this project we will develop new technologies inspired by the whisker morphology and neural processing systems of two such tactile specialists: the Norwegian rat and the Etruscan shrew. These animals sweep their whiskers back and forth at high speeds in a controlled and feedback-sensitive manner. This "active touch" capacity allows them to: (i) maximise their intake of useful information (ii) solve perceptual tasks such as determining the position, shape, and surface texture of encountered objects (iii) encode tactile memories that allow recognition of familiar items and (iv) track and capture prey animals using touch signals alone. Using our understanding of these natural vibrissal systems we will develop two biomimetic artefacts endowed with similar sensing capabilities: a novel active tactile sensing array, termed a BIOTACT sensor, which will be mounted on a robot manipulator arm and incorporate a large number of whisker-like sensing elements and an autonomous whiskered robot that can seek-out, identify, and track fast-moving target objects.
Overall, our project will bring about a step- change in the understanding of active touch sensing and in the use of whisker-like sensors in intelligent machines. BRL is a partner in the BIOTACT consortium and is responsible for the majority of the robotics aspects of the project.
The BRL robot manipulator arm was designed and built by Elumotion Ltd (http://www.elumotion.com). in a partnership with BRL
The external BIOTACT project website
This file last updated Friday, 02-Oct-2009 16:25:28 BST
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