are used to determine the safe operational extremities of motion on the robot. Limit switches prevent hyperextension of joints that could cause serious damage to the robotic system. Additionally, Limit switches are commonly used to calibrate Joint
location in the initialization period of robotic activity.
Knowing when a joint or appendage has reached its limit of safe operation is important for the robot. Limit "switches" can be a host of different sensors since all they need to do is notify the robot somehow. They can include: Laser range finders, ultrasonic sensors, physical push-button / lever switches, Infrared
& light curtain switches, potentiometer limits, or even reed switches.
Limits of the robot can sometimes be determined without any limit switches during an initial Calibration
routine. in this case, a physical stop could be used where the robot slowly approaches its range of motion until it detects a change in force (current detection). Once this detection occurs, the robot will have determined its range of motion.