Next to vision in importance is tactile sensing or touching. Imagine the blind can do delicate jobs relying on his/her sensitive tactile.Cnc machining A blind robot can be extremely effective in performing an assembly task using only a sense of touch. Touch is of particular importance for providing feedback necessary to grip delicate objects firmly without causing damage to them.
To simulate tactile in human hands, a complete tactile-sensing system must perform three fundamental sensing operations: (1) joint force sensing which senses the force applied to the robot’s hand, wrist and arm joints; (2) touch sensing which senses the pressure applied to various points on the hand’s surface or the gripper’s surface; (3) slip sensing which senses any movement of the object while it is being grasped.
The joint forces are usually sensed using various strain gauges arranged in robot wrist assembly.Cnc machining A strain gauge is a force—sensing element whose resistance change in proportion to the amount of the force applied to the element. The simplest application of touch sensor is a gripper equipped with an array of miniature microswitches. This type of sensor can only determine the presence or absence of an object at a particular point or an array of points of the robot hand. A more advanced type of touch sensors uses arrays of pressure-sensitive piezoelectric material (conductive rubber or foam, etc.). The arrangement allows the sensor to perceive changes in force and pressure within the robot hand. Since the force at each point can be determined, the force on its surface can be mapped and the shapes of objects grasped in the robot hand can be determined respectively. Slip sensing is required for a robot to create the optimum amount of grasping force applied to be picked up without the danger of being dropped. The gripping force is increased step by step until the object has been firmly grasped and no more slip occurs
The integration of tactile sensing and vision sensing can dramatically enhance robotic assembly task. An example of this type of sensors would be a vision sensor used to locate and identify objects and positing of the robot itself, combined with a tactile sensor used to detect the distribution of force and pressure, and determine torque, Cnc machiningweight, center of mass and compliance of the material it handles. The hand-eye coordination for general-purpose manipulation will be extremely powerful in the industrial world.