Sensors

Sensors

1. Vision

   • computer vision system
   • video camera linked to computer
     • view robots workspace
       • pick up objects at unknown location
       • find position and orientation of object
       • recognise objects
         • bin picking
     • on end effector
       • close up views of object
       • increasing accuracy of position
     • view end effector
       • tell robot if successfully picked up object
       • where object is in gripper
   • software to analyse images captured

2. Tactile

   • human sense of touch
   • pressure sensitive pads on inside of gripper fingers
   • convert pressure on pads to electrical signal
   • determine location of part in gripper
   • check part is in gripper
   • control force exerted by gripper
   • recognise shape of part
   • Lord Corporation
     • surface of tactile pad 2D array of pressure sensitive sites
     • pressure applied rod pushed down blocks light
     • amount of pressure determined by amount of light blocked
   • Polymers
     • pressure changes electrical properties of polymers
     • electrical circuit embedded in pad of polymers
     • detect pressure change and distribution
   • limited technology

3. Range

   • mounted on end effector
     • ultra sonic
     • laser
       • laser projects on spot on surface triangulation computes distance
   • measures distance to an object
   • find position of unknown object
   • maintain fixed distance between end effector and part

4. Force/ Torque

   • wrist of robot
   • measures forces and torques on end effector using strain gauges
     • measure small movements by applied forces/torques
     • microprocessor computers forces/torques from strain gauge values
   • maintain constant force between end effector and part
     • eg deburring , grinding
   • detect misalignment forces

5. sensory feedback

   • more complex info about environment provided
   • measure a variable and alter the computer programme based on these results
   • in end effector
   • around the workplace

6. Simple

   • binary
   • on or off
   • signals robot to stop/start