1. ECE 450 Introduction to Robotics
Section:
Instructor: Linda A. Gee
10/26/99
Lecture 13

2. Tactile and Proximity Sensing
Tactile Sensors
provide collision indication with surroundings in terms of direct physical contact; used on automated guided vehicles (AGVs)
Proximity Sensors
provide advance warning of the presence of an object and are non-contact devices
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3. Tactile Sensors Tactile sensor methods Contact closure Magnetic
Piezoelectric
Capacitive
Photoelectric
Magnetoresistive
Piezoresistive
Ultrasonic
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4. Tactile Sensors for Mobile Robots
Tactile feelers or antennae
Tactile bumpers
Distributed surface arrays
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5. Tactile Feelers Active Passive possess mechanical components
rely on relative motion between the robot and the object
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6. Tactile Bumpers Simple sensor
designed to form a contact closure when pressure is applied to the bumper
other actuators can be used to trigger control or decisions concerning course of action
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7. Distributed Surface Arrays
Skin-like sensor used with manipulators
uses an outer surface, typically rubber to determine the contact or compression of the surface
provides robotic orientation sensing for industrial applications
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8. Proximity Sensors Proximity sensor methods Magnetic Inductive
Capacitive
Ultrasonic
Microwave
Optical
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9. Magnetic Proximity Sensors
Types of magnetic proximity sensors
Magnetic reed switches: hermitically sealed
Hall Effect sensors: voltage and magnetic field
Magnetoresistive sensors: change in resistivity with motion
Giant Magnetoresistance devices (GMR): linear operation
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10. Inductive Proximity Sensors
Commonly used in industrial sensors
capable of sensing through non-metallic materials
operating characterisitics are versatile
insensitive to cosmetic alterations
can be submerged in fluids and maintain operation
size variation determines sensing range capability
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11. Capacitive Proximity Sensors
Detects a change in capacitance or electric field due to object presence
Capable of sensing
dielectric materials
metals
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12. Ultrasonic Proximity Sensors
Reflective sensor
Responds to the change in the energy emitted and returned to a detector: acoustics
Distance characteristics
Detects
liquids
objects
solids
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13. Microwave Proximity Sensors
Reflective sensor
Emits electromagnetic energy in the microwave region of the RF spectrum
Doppler shift indicates the presence of an object
Transmitter - Receiver pair required
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14. Optical Proximity Sensors
Photoelectric sensors
Three groups
opposed: electric eye; emitter/detector beam interrruption
retroreflective: uses an object to reflect from emitter to the detector
diffuse: uses the target object to return the energy from the emitter to the detector
Lecture 13