A Current Limit can be set in software to limit the amount of current sent to a motor or joint. This will reduce the maximum motor power and is commonly used to prevent the robot from damaging itself, such as when stuck. This pairs with the robot's current monitor, which when it detects too high of a current can be used to alert the robot in various ways.
A current limit can be set to prevent something from spinning too fast, or gripping an item too h...
Read More -> | A fuse is a “weak link” in a circuit that is built in to provide protection for other components within your robot. A fuse generally consists of a thin wire that is designed to melt/vaporize when a certain amount of current is passed through the fuse. Fuses are made to “blow” before any other portion of a circuit and will protect electronics from situations that could otherwise destroy sensitive parts or lead to fire.
Fuses come in all sorts of sizes, and current ratings. They are also cl...
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The Emergency Stop (E-Stop) is a physical button is placed on a robot that allows anyone within reach to physically disable the robot. This feature acts as a critical safety device on large robots that have the potential to cause significant harm to other machinery or people. Usually the E-Stop is a large red colored button that is placed on an easily accessible part of robot. Depending on the robot design, the E-stop will usually disable the power elec...
Read More -> | Grounding is used as a safety feature on some circuits and equipment to prevent the device from shocking the user. Robots that might source power from the mains (wall socket) sometimes have a third prong on the power cable. This third prong (common on all computer power cables) contains an "earth ground" connection which is connected to any exposed metal surface - such as a metal case or body panel.
Earth ground is an important safety feature becaus...
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An Interlock is a safety feature that when triggered will place a robot into a safe condition to reduce the hazards that could injure you or your robot. Many industrial robots have interlocks that will shutdown the system when tripped to prevent harm. Interlocks are usually placed on access doors or panels of robots that notify the robot that it is not in a normal operational mode. Usually if the problem is fixed (such as closing an access panel), the robot wil...
Read More -> | Leak detectors can be used to sense when a robot might be operating in an unsafe or humid environment. If a robot commonly operates in or around water, the robot may contain a Leak Detector circuit. A leak detector circuit will allow the robot to move to a safer place, trigger a warning alarm, or shutdown to prevent damage.
Leak detectors usually contain a pad or a set of electrodes that when immersed in a slightly conductive liquid, can detect the chan...
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Limit switches 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....
Read More -> |  Cheetah by Boston Dynamics tethered to the ceiling. A Tether can be used to restrain a robot’s movement. Tethers can prevent robot damage by restricting motion into a dangerous area, or can be used to safely extract a robot from its environment if a loss of power or control occurs. A tether might be used in a situation where a robot is operating near a hazard, such as other robotic equipment, water, or a large drop off, where it is necessary to restrict movement or prevent the robot from falling over. Tethers are m...
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A Thermal Fuse is a fusible link that is placed into a circuit that will “blow” when a certain temperature is reached. Thermal fuses are common in lithium-ion battery packs where there is a higher potential for fire. To reduce the potential for fire, a thermal fuse will cut battery power. Once the thermal fuse blows, the fuse’s conducting path is physically destroyed and must be replaced.
In contrast, a thermal cut off switch (TCO) will reset itself...
Read More -> | A Thermistor is a temperature sensor that can be used to monitor internal temperatures of the robot. Usually thermistors are used on battery packs to monitor the it while charging and discharging. If a battery pack gets too hot, the robot or charging system will acknowledge that and take steps to reduce the temperature (stop charging, shutdown the system, etc.). A thermistor is an important element in the battery monitoring system.
Thermistors are ...
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The Watchdog Timer is a timer that is integrated into software or hardware that will trigger a system reset or put the system in a fail-safe mode if the program stalls for an unknown reason. A watchdog timer is set to run for a certain amount of time and when the timer runs out - it enters the system into the designated state. If the timer is reset before this occurs, then the system will continue to operate as normal until it runs out again. Management...
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