Basic HTML Version

|  | Table of Contents |  | View Full Version

Page 118 - Toucpad robotics C11
P. 118

    Working Principle
                      Simple Touch Sensor (Switch-Based): Works like a push-button switch. When physical contact is made, it closes an
                  u
                      electrical circuit, sending a digital signal (ON/OFF) to the robot’s controller.
                      Force/Pressure Sensors (Resistive/Capacitive): More advanced tactile sensors measure the amount of force or
                  u
                      pressure applied.
                      ∑  Resistive: Their electrical resistance changes when pressure is applied.
                      ∑	 Capacitive: Their electrical capacitance changes when they are pressed or touched.
                      These changes in electrical properties are then converted into an analogue or digital signal proportional to the
                  u
                      applied force.
                      Arrays of Sensors: Some advanced tactile sensors are arrays of tiny individual sensors spread over a surface (like
                  u
                      a robot’s fingertip or palm), allowing the robot to not just detect contact but also the shape and texture of an object,
                      or how pressure is distributed.
                  Applications in Robotics
                      Grasping and Manipulation: Essential for robotic grippers to detect when they have made contact with an object
                  u
                      and to adjust gripping force to avoid crushing delicate items or dropping heavy ones.
                      Collision  Detection: Detecting  unexpected  contact  with obstacles  or people  to  trigger  a safety  stop  (especially
                  u
                      important for collaborative robots).
                      Surface Following: Guiding a robot along a surface by maintaining light contact.
                  u
                      Assembly Tasks: Confirming that components are properly seated or fastened by feeling the force feedback.
                  u
                      Human-Robot Interaction: Enabling robots to respond to human touch, for example, a robot responding when its
                  u
                      hand is held.
                  Advantages

                      Direct Interaction: Provides direct information about physical contact, pressure, and force.
                  u
                      Simple for Basic Detection: Simple switch-based touch sensors are very easy to implement and cost-effective.
                  u
                      Safety Enhancement: Crucial for ensuring safe interaction between robots and their environment/humans.
                  u
                      Enables Delicate Tasks: Allows robots to perform tasks requiring a “sense of feel.”
                  u
                  Disadvantages

                      Limited Spatial Resolution: Simple touch sensors only provide point contact information. Advanced arrays are better
                  u
                      but more complex.
                      Wear and Tear: Mechanical touch sensors can degrade over time due to repeated physical contact.
                  u
                      Not for Remote Sensing: Cannot detect objects from a distance; requires direct physical contact.
                  u
                      Can be Fragile: Some highly sensitive force sensors can be delicate.
                  u
                  Gyroscopes and Accelerometers (Often Combined in an Inertial Measurement Unit - IMU)

                  These  two  types  of  sensors  are often  found  together  in  a single  unit  called  an
                  Inertial Measurement Unit (IMU). They are crucial for a robot’s understanding of
                  its own motion and orientation.

                  Gyroscopes

                  Description
                  A Gyroscope (specifically a Micro-Electro-Mechanical Systems or MEMS gyroscope
                  commonly used in robotics) is a sensor that measures angular velocity, which is
                  the rate of rotation around an axis.

                  116
                  Touchpad Robotics - XI

| 113 114 115 116 117 118 119 120 121 122 123 |