Chapter 30: Traditional Safety |
Fences, interlocked gates, light curtains, and safety-rated controllers force protective stops when humans enter the workspace. |
30.1 A Short Summary of What This Chapter Covers |
This chapter explains the traditional approach to industrial robot safety. Traditional safety is the set of physical and electrical measures that keep people away from moving robots, or that stop the robot when a person gets too close. The main tools are hard fences, interlocked gates, light curtains, safety mats, area scanners, and safety-rated controllers. These devices are reliable, well understood, and accepted by regulators around the world. They do not require the robot to know where the human is at every moment. Instead, they create a clear boundary between the human world and the robot world. When that boundary is crossed, the robot stops. |
The chapter is written for a general technical reader. It avoids formulas and tables. It uses plain language and many real examples from different industries. The goal is to show how traditional safety works in practice, why it remains the backbone of robot safety, and where it fits in modern factories, warehouses, hospitals, and farms. The chapter also explains the limits of traditional safety, because those limits motivated the collaborative systems described in later chapters. |
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30.2 Why Traditional Safety Still Matters |
Robots are strong, fast, and tireless. A large industrial robot can move a payload of several hundred kilograms at a speed of two meters per second. If a person is in the way, the result can be fatal. For this reason, the first rule of robot safety has always been separation. Keep people out of the robot's workspace during operation. If they must enter, stop the robot first. |
This rule is simple, but it has deep consequences. It shapes the layout of factories. It determines how production lines are organized. It affects maintenance procedures. It even affects the training of operators. Traditional safety is not just a box of devices. It is a way of thinking about the relationship between humans and machines. |
Traditional safety remains important for several reasons. First, it is proven. Hard fences and interlocked gates have protected workers for decades. Second, it is accepted by standards organizations such as the International Organization for Standardization and the American National Standards Institute. Third, it is cost effective for many applications. A fence costs far less than a sophisticated vision system. Fourth, it is robust. A fence does not need software updates. It does not misinterpret a shadow. It does not fail because of a network problem. |
Finally, traditional safety is the foundation on which collaborative safety is built. Even a collaborative robot often needs a fence in some parts of its workspace. Even a mobile robot in a warehouse may need a safety-rated stop when it enters a restricted zone. Understanding traditional safety is therefore essential for understanding any robot safety system. |
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30.3 The Core Principle: Protective Stop |
The heart of traditional safety is the protective stop. A protective stop is a controlled stop of the robot that is initiated by a safety device. It is not the same as an emergency stop, although both stop the robot. An emergency stop is manual, usually triggered by a person pressing a button. A protective stop is automatic, triggered by a sensor or an interlock. |
A protective stop has three important properties. First, it must be reliable. The robot must stop even if a component fails. Second, it must be fast. The stopping time must be short enough to prevent injury. Third, it must be predictable. The robot must follow a defined stopping path, not veer off in an unexpected direction. |
Safety-rated controllers make this possible. A safety-rated controller is a computer that meets strict standards for reliability. It uses redundant channels, self-checking circuits, and fail-safe logic. If one channel fails, the other channel still stops the robot. If a wire breaks, the system detects the break and stops the robot. This is often called fail-safe design. The idea is that the safe state is the default state. Any failure leads to a stop, not to a dangerous motion. |
In practice, a protective stop may be a category 0 stop, a category 1 stop, or a category 2 stop. These categories come from international standards. A category 0 stop removes power immediately. The robot coasts to a halt. A category 1 stop removes power after the robot has stopped. A category 2 stop keeps power on but holds the robot in a safe position. The choice depends on the application. For a heavy robot carrying a fragile load, a category 1 stop may be better because it avoids a sudden drop. For a small robot, a category 0 stop may be sufficient. |
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30.4 Hard Fences: The First Line of Defense |
A hard fence is a physical barrier that surrounds the robot. It is usually made of metal mesh, polycarbonate panels, or a combination of both. The fence must be strong enough to withstand the force of a robot collision. It must also be high enough to prevent a person from reaching over it. The exact height and strength depend on the robot's size, speed, and payload. |
Hard fences are used in almost every industry. In an automotive plant, a fence may surround a welding cell with six large robots. In a food processing plant, a stainless steel fence may surround a palletizing robot. In a semiconductor factory, a clear fence may surround a wafer handling robot so that operators can watch the process. |
The design of a hard fence is not trivial. It must allow access for maintenance. It must allow cables and hoses to pass through. It must allow air to flow for cooling. It must not create a trap where a person can be crushed between the fence and the robot. It must be anchored to the floor so that it does not move if the robot hits it. |
A common mistake is to build a fence that is too low or too weak. A robot moving at full speed can bend a thin panel or push a mesh outward. The fence must be rated for the worst-case impact. Standards provide guidance, but the final responsibility lies with the integrator and the end user. |
Another common mistake is to leave gaps. A gap at the bottom of a fence may allow a small person or a child to crawl through. A gap at the top may allow a person to reach over. A gap at a corner may allow a person to slip around. These gaps must be closed or protected by other devices. |
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30.5 Interlocked Gates: The Door That Stops the Robot |
An interlocked gate is a door in the fence that stops the robot when it is opened. The interlock is a switch that detects whether the gate is closed. If the gate is open, the safety-rated controller receives a signal and initiates a protective stop. The robot cannot restart until the gate is closed and the system is reset. |
There are several types of interlock. A mechanical interlock uses a key or a latch. A magnetic interlock uses a magnet and a reed switch. A radio frequency interlock uses a coded signal. A non-contact interlock uses an inductive or optical sensor. The choice depends on the environment. In a dirty factory, a non-contact interlock may be more reliable because it has no moving parts. In a clean room, a magnetic interlock may be preferred because it is sealed. |
Interlocked gates are everywhere. In a warehouse, a gate may protect a robotic palletizing cell. In a machine shop, a gate may protect a robotic loading cell. In a laboratory, a gate may protect a robotic sample handler. The gate is often equipped with a lock that prevents it from being opened while the robot is moving. This is called a trapped-key interlock. The operator must take the key with them when they enter, so that no one else can start the robot. |
A critical design issue is the reset procedure. After the gate is closed, the robot should not restart automatically. The operator must perform a deliberate reset, usually by pressing a button inside the cell or at a control panel. This ensures that no one is still inside. Some systems use a presence-sensing device, such as a scanner, to confirm that the cell is empty before reset. This is called a safe start-up check. |
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30.6 Light Curtains: Invisible Barriers |
A light curtain is a set of infrared beams that form an invisible barrier. When a person or object breaks a beam, the safety-rated controller initiates a protective stop. Light curtains are used where a physical fence would be inconvenient. For example, a robot may need to load and unload parts from a conveyor. A light curtain can protect the opening while allowing parts to pass through. |
Light curtains come in many sizes. A small curtain may protect a single opening. A large curtain may span several meters. The resolution of the curtain, meaning the spacing between beams, determines the smallest object it can detect. A curtain with a resolution of 14 millimeters can detect a finger. A curtain with a resolution of 30 millimeters can detect a hand. A curtain with a resolution of 50 millimeters can detect a body. |
Light curtains are common in the automotive industry. A robot may weld a car body inside a cell. The operator loads parts through an opening protected by a light curtain. When the operator reaches in, the curtain stops the robot. When the operator withdraws, the robot resumes. This is called a muted or blanked curtain if some beams are intentionally ignored to allow a part to pass. |
Light curtains are also used in packaging. A robot may pick and place items on a high-speed line. A light curtain protects the operator who feeds the line. If the operator reaches in, the robot stops. This prevents the robot from hitting the operator's hand. |
A key advantage of light curtains is that they do not take up floor space. A fence needs room for the gate to swing open. A light curtain needs only a transmitter and a receiver. This makes light curtains ideal for tight spaces. A key disadvantage is that they can be blinded by dust, steam, or sunlight. They must be cleaned and aligned regularly. They also cannot protect against a person who approaches from the side or from above. |
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30.7 Safety Mats and Edge Sensors |
A safety mat is a pressure-sensitive floor mat that detects when a person steps on it. When the mat is stepped on, the safety-rated controller initiates a protective stop. Safety mats are used around robots where a fence would block access. For example, a robot may be mounted on a pedestal in the middle of a work area. A mat around the pedestal protects the operator who approaches from any direction. |
Safety mats are common in assembly. A robot may cooperate with a human in a shared workstation. The mat defines the robot's zone. If the human steps into the zone, the robot stops. If the human steps out, the robot resumes. This is a simple form of zone control. |
Safety mats must be designed carefully. They must not create a tripping hazard. They must be sealed against liquids. They must be tested regularly. A mat that fails to detect a step is a serious hazard. A mat that triggers too easily is an annoyance that leads operators to bypass it. |
An edge sensor is a strip that detects contact. It is often used on the edge of a moving robot or on the edge of a door. When the strip is touched, the robot stops. Edge sensors are common on collaborative robots, but they are also used on traditional robots. For example, a robot may have an edge sensor on its end effector to detect a collision with a fixture. This protects both the robot and the fixture. |
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30.8 Area Scanners: Watching the Whole Space |
An area scanner is a device that uses laser or radar to scan a region of space. It detects when a person enters the region. When a person enters, the safety-rated controller initiates a protective stop or a speed reduction. Area scanners are more flexible than light curtains because they can cover a complex shape. They can also have multiple zones. For example, a scanner may define a warning zone and a stop zone. When a person enters the warning zone, the robot slows down. When the person enters the stop zone, the robot stops. |
Area scanners are common in mobile robots. A mobile robot in a warehouse uses scanners to detect people and obstacles. The scanner may define a protective field in front of the robot. If a person steps into the field, the robot stops. If the person steps aside, the robot resumes. This is essential for safe navigation in a shared space. |
Area scanners are also used in fixed cells. A robot may be surrounded by a scanner instead of a fence. The scanner defines a virtual fence. When a person crosses the virtual fence, the robot stops. This is called a virtual fence or a safeguarded space. It is popular in factories where a physical fence would block the flow of materials. |
Area scanners have limitations. They can be blocked by dust, fog, or reflective surfaces. They can have blind spots. They can be confused by multiple people. They must be configured carefully to avoid false stops. Despite these limitations, they are a powerful tool for traditional safety. |
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30.9 Safety-Rated Controllers: The Brain of the System |
A safety-rated controller is the device that receives signals from all the safety devices and decides when to stop the robot. It is the brain of the traditional safety system. It must be designed to a high level of reliability. It must be certified by a recognized body. It must be tested regularly. |
A safety-rated controller typically has two independent channels. Each channel processes the same inputs. If the two channels disagree, the controller stops the robot. This is called diversity. It prevents a single fault from causing a dangerous failure. The controller also monitors the robot's speed, position, and direction. If the robot moves too fast or too far, the controller stops it. |
Safety-rated controllers are used in every industry. In a steel mill, a controller may manage the safety of a robot that handles hot metal. In a pharmaceutical plant, a controller may manage the safety of a robot that handles toxic compounds. In a warehouse, a controller may manage the safety of a fleet of mobile robots. |
A key feature of modern safety-rated controllers is the ability to configure them with software. This makes it easy to change the safety zones when the layout changes. It also makes it easy to diagnose problems. The controller can log events, such as a gate opening or a curtain breaking. This log is invaluable for troubleshooting and for proving compliance. |
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30.10 Applications in Automotive Manufacturing |
The automotive industry is the largest user of industrial robots. It is also the industry where traditional safety is most highly developed. A typical automotive body shop has hundreds of robots. Each robot is surrounded by a fence. Each fence has one or more interlocked gates. Each gate has a trapped-key interlock. The robots weld, seal, and handle parts. The operators load and unload parts, inspect welds, and perform maintenance. |
In this environment, traditional safety is a way of life. The plant is divided into cells. Each cell is a safeguarded space. The boundary of the cell is a fence or a light curtain. The entrance is a gate. The gate is interlocked. The robot cannot move unless the gate is closed and the cell is clear. The operator cannot enter unless the robot is stopped. This is called a lockout-tagout procedure. The operator takes a key, enters the cell, and performs the task. When the task is done, the operator leaves, closes the gate, and returns the key. The robot can then restart. |
A specific example is a robotic welding cell. The cell has two robots on opposite sides. The robots weld a car frame. The frame is loaded by a conveyor. A light curtain protects the loading opening. When the frame enters, the curtain is muted. When the frame is in position, the curtain is unmuted. If an operator reaches in, the curtain stops the robots. This allows the operator to inspect the weld without stopping the line. If the operator needs to enter the cell, they must open the gate. The gate stops the robots. The operator takes the key and enters. The robots cannot restart until the gate is closed and the key is returned. |
Another example is a robotic painting cell. The cell is enclosed to contain the paint mist. The robots paint the car body. The cell has a light curtain at the entrance. The curtain is designed to detect a person, not a car body. The car body is large, so the curtain must be muted when the body enters. This is done with a muting sensor that detects the body and temporarily disables the curtain. If a person follows the body into the cell, the muting sensor does not detect them, and the curtain stops the robots. This is a sophisticated use of traditional safety. |
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30.11 Applications in Electronics Manufacturing |
The electronics industry uses small robots for assembly, testing, and handling. The robots are often fast and precise. They may handle fragile parts such as wafers, circuit boards, and displays. Traditional safety is used to protect both the operator and the product. |
In a semiconductor factory, a robot may handle a wafer cassette. The robot is inside a mini-environment. The mini-environment is a sealed box with a clear window. The operator loads and unloads cassettes through a port. The port has a light curtain. If the operator reaches into the port while the robot is moving, the curtain stops the robot. This prevents the operator from being injured and prevents the wafer from being damaged. |
In a circuit board factory, a robot may place components on a board. The robot is inside a cell. The cell has a fence with an interlocked gate. The operator loads boards through a magazine. The magazine is inside the cell. The operator must open the gate to load the magazine. The gate stops the robot. The operator loads the magazine, closes the gate, and restarts the robot. This is a simple and effective use of traditional safety. |
In a display factory, a robot may handle a large glass panel. The panel is fragile and expensive. The robot is inside a clean room. The clean room has a fence with a light curtain. The curtain is designed to detect a person, not the panel. The panel is moved by a conveyor. The conveyor has a muting sensor that disables the curtain when the panel passes. If a person tries to enter, the curtain stops the robot. This protects the person and the panel. |
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30.12 Applications in Food and Beverage |
The food and beverage industry uses robots for palletizing, packaging, and processing. The environment is often wet, cold, or hot. The robots may be washed with water or chemicals. Traditional safety must be designed for these conditions. |
In a meat processing plant, a robot may cut and pack meat. The robot is inside a stainless steel cell. The cell has a fence with an interlocked gate. The gate has a washdown-rated interlock. The interlock is sealed to prevent water from entering. The robot is washed daily. The operator must enter the cell to clean the robot. The operator opens the gate, takes the key, and enters. The robot cannot restart until the gate is closed and the key is returned. |
In a bakery, a robot may pick and place bread. The robot is inside a cell. The cell has a light curtain. The curtain is designed to detect a person, not the bread. The bread is moved by a conveyor. The conveyor has a muting sensor that disables the curtain when the bread passes. If a person tries to enter, the curtain stops the robot. This prevents the person from being burned by the oven or injured by the robot. |
In a bottling plant, a robot may palletize bottles. The robot is inside a cell. The cell has a fence with an interlocked gate. The gate has a trapped-key interlock. The operator loads bottles onto a conveyor. The conveyor moves the bottles into the cell. The robot palletizes the bottles. The operator must enter the cell to clear a jam. The operator opens the gate, takes the key, and enters. The robot cannot restart until the gate is closed and the key is returned. This is a classic use of traditional safety. |
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30.13 Applications in Logistics and Warehousing |
The logistics and warehousing industry uses robots for palletizing, depalletizing, sorting, and transporting. The environment is often dynamic. People and robots share the same space. Traditional safety is used to separate them. |
In a distribution center, a robot may palletize boxes. The robot is inside a cell. The cell has a fence with an interlocked gate. The gate has a trapped-key interlock. The operator loads boxes onto a conveyor. The conveyor moves the boxes into the cell. The robot palletizes the boxes. The operator must enter the cell to change the pallet. The operator opens the gate, takes the key, and enters. The robot cannot restart until the gate is closed and the key is returned. This is a simple and effective use of traditional safety. |
In a parcel sorting center, a robot may sort parcels. The robot is inside a cell. The cell has a light curtain. The curtain is designed to detect a person, not a parcel. The parcels are moved by a conveyor. The conveyor has a muting sensor that disables the curtain when a parcel passes. If a person tries to enter, the curtain stops the robot. This prevents the person from being injured by the robot. |
In a warehouse, a mobile robot may transport goods. The mobile robot uses area scanners to detect people and obstacles. The scanner defines a protective field in front of the robot. If a person steps into the field, the robot stops. If the person steps aside, the robot resumes. This is essential for safe navigation in a shared space. The mobile robot may also use a safety-rated controller to manage its speed and direction. If the robot enters a restricted zone, the controller slows it down or stops it. |
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30.14 Applications in Pharmaceuticals and Healthcare |
The pharmaceutical and healthcare industries use robots for dispensing, compounding, testing, and surgery. The environment is often clean and precise. Traditional safety is used to protect both the operator and the product. |
In a pharmaceutical plant, a robot may dispense toxic compounds. The robot is inside a glovebox or an isolator. The isolator is a sealed box with gloves. The operator manipulates the robot through the gloves. The isolator has a fence with an interlocked gate. The gate has a trapped-key interlock. The operator must enter the isolator to change a container. The operator opens the gate, takes the key, and enters. The robot cannot restart until the gate is closed and the key is returned. This protects the operator from the toxic compound. |
In a hospital, a robot may deliver medications. The robot is a mobile robot. The robot uses area scanners to detect people and obstacles. The scanner defines a protective field in front of the robot. If a person steps into the field, the robot stops. If the person steps aside, the robot resumes. This is essential for safe navigation in a crowded hospital. The robot may also use a safety-rated controller to manage its speed and direction. If the robot enters a restricted zone, the controller slows it down or stops it. |
In a surgical robot, traditional safety is used in a different way. The surgical robot is not separated from the patient by a fence. Instead, the robot is designed to be inherently safe. It has redundant sensors, limited force, and a surgeon who is in control. Traditional safety devices such as light curtains and safety mats are not used. However, the principles of traditional safety, such as redundancy and fail-safe design, are still applied. |
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30.15 Applications in Agriculture and Construction |
The agriculture and construction industries use robots for harvesting, planting, welding, and inspection. The environment is often unstructured. Traditional safety is used to protect the operator from the robot. |
In a greenhouse, a robot may harvest tomatoes. The robot is a mobile robot. The robot uses area scanners to detect people and obstacles. The scanner defines a protective field in front of the robot. If a person steps into the field, the robot stops. If the person steps aside, the robot resumes. This is essential for safe navigation in a crowded greenhouse. The robot may also use a safety-rated controller to manage its speed and direction. If the robot enters a restricted zone, the controller slows it down or stops it. |
In a construction site, a robot may weld a beam. The robot is a mobile robot. The robot uses area scanners to detect people and obstacles. The scanner defines a protective field in front of the robot. If a person steps into the field, the robot stops. If the person steps aside, the robot resumes. This is essential for safe navigation in a cluttered site. The robot may also use a safety-rated controller to manage its speed and direction. If the robot enters a restricted zone, the controller slows it down or stops it. |
In a farm, a robot may plant seeds. The robot is a mobile robot. The robot uses area scanners to detect people and obstacles. The scanner defines a protective field in front of the robot. If a person steps into the field, the robot stops. If the person steps aside, the robot resumes. This is essential for safe navigation in a field. The robot may also use a safety-rated controller to manage its speed and direction. If the robot enters a restricted zone, the controller slows it down or stops it. |
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30.16 The Limits of Traditional Safety |
Traditional safety has limits. It is based on separation. It assumes that the human and the robot are in different spaces. When they are in the same space, traditional safety stops the robot. This is safe, but it is not efficient. Every time a human enters the workspace, the robot stops. This reduces productivity. It also creates a temptation to bypass the safety devices. Operators may disable a light curtain to keep the line running. This is dangerous. |
Traditional safety also has limits in unstructured environments. A fence works well in a factory. It does not work well in a hospital or a farm. A mobile robot cannot be surrounded by a fence. It must use area scanners and other devices to detect people. These devices have blind spots and can be confused by the environment. They are not as reliable as a fence. |
Traditional safety also has limits in collaborative applications. A collaborative robot is designed to work alongside a human. It cannot be separated by a fence. It must use force limiting, speed limiting, and other techniques to avoid injury. These techniques are the subject of later chapters. |
Finally, traditional safety has limits in cost. A fence, a gate, a light curtain, and a safety-rated controller can cost tens of thousands of dollars. This is acceptable for a large automotive plant. It is not acceptable for a small workshop. For this reason, many small companies use collaborative robots that do not require a fence. This is one of the reasons for the growth of collaborative robots. |
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30.17 Designing a Traditional Safety System |
Designing a traditional safety system is a systematic process. It begins with a risk assessment. The risk assessment identifies the hazards, the people who are exposed, and the severity of the potential injury. It also identifies the tasks that require access to the robot. The risk assessment is used to determine the required safety measures. |
The next step is to select the safety devices. The choice depends on the application. A fence is used where access is not required during operation. A light curtain is used where access is required but the opening is small. An area scanner is used where access is required and the space is complex. A safety mat is used where access is required and the floor is the only path. |
The next step is to design the safety-related control system. The controller must be safety-rated. It must have redundant channels. It must be able to detect faults. It must be able to stop the robot in a controlled manner. The controller must also be able to reset the system only after the hazard is removed. |
The next step is to install and validate the system. The installation must follow the manufacturer's instructions. The validation must include a functional test. The test must verify that each device stops the robot when it is triggered. The test must also verify that the robot cannot restart until the system is reset. |
The final step is to document the system. The documentation must include the risk assessment, the design, the installation, and the validation. The documentation must be kept for the life of the robot. It is used for training, for maintenance, and for compliance. |
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30.18 Training and Procedures |
Traditional safety is not just about devices. It is also about people. Operators, maintenance workers, and engineers must be trained. They must understand the hazards. They must understand the safety devices. They must understand the procedures. |
A key procedure is lockout-tagout. Lockout-tagout is a procedure that ensures that the robot is stopped and cannot be restarted while a person is inside the cell. The procedure involves placing a lock on the energy isolation device and a tag that identifies the person who placed the lock. The person who placed the lock is the only one who can remove it. This prevents someone else from restarting the robot. |
Another key procedure is safe start-up. Safe start-up is a procedure that ensures that the cell is clear before the robot is restarted. The procedure involves a visual inspection, a audible warning, and a deliberate reset. The visual inspection confirms that no one is inside. The audible warning alerts anyone who may be inside. The deliberate reset ensures that the operator intends to start the robot. |
Another key procedure is maintenance. Maintenance must be performed with the robot stopped. The maintenance worker must follow the lockout-tagout procedure. The maintenance worker must also be trained on the specific robot and the specific safety devices. The maintenance worker must not bypass a safety device. If a safety device must be bypassed for testing, the bypass must be temporary and must be controlled. |
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30.19 Standards and Regulations |
Traditional safety is governed by standards and regulations. The most important international standard is ISO 10218. This standard has two parts. Part 1 covers the robot itself. Part 2 covers the robot system and integration. The standard specifies requirements for protective stops, safety-rated controllers, and safeguarding. |
Another important standard is ISO 13849. This standard specifies the performance level of safety-related control systems. It defines categories and performance levels. A higher performance level means a more reliable system. The performance level is determined by the risk assessment. |
In the United States, the relevant standard is ANSI/RIA R15.06. This standard is harmonized with ISO 10218. It provides guidance for the design, installation, and use of industrial robots. |
In Europe, the relevant directive is the Machinery Directive. This directive requires that machines meet essential health and safety requirements. The directive is supported by harmonized standards such as ISO 10218 and ISO 13849. |
These standards and regulations are not optional. They are legal requirements in many countries. They are also good engineering practice. Following them ensures that the safety system is effective and that the company is protected from liability. |
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30.20 Common Mistakes and How to Avoid Them |
There are many common mistakes in traditional safety. One mistake is to use the wrong device. A light curtain is not a fence. It does not protect against a person who approaches from the side. An area scanner is not a light curtain. It can be blocked by dust. The device must be selected for the specific application. |
Another mistake is to install the device incorrectly. A light curtain must be aligned. A safety mat must be sealed. A fence must be anchored. An interlock must be positive-acting. The installation must follow the manufacturer's instructions. |
Another mistake is to bypass the device. Operators may bypass a light curtain to keep the line running. Maintenance workers may bypass an interlock to test the robot. Bypassing is dangerous. It must be controlled and temporary. It must be documented. It must be removed as soon as possible. |
Another mistake is to forget the reset. A safety system must not restart automatically. The operator must perform a deliberate reset. The reset must be located outside the hazardous area. The reset must not be reachable from inside the hazardous area. This prevents an operator from resetting the system while still inside. |
Another mistake is to forget the training. A safety system is only as good as the people who use it. Operators must be trained. Maintenance workers must be trained. Engineers must be trained. Training must be repeated regularly. Training must be documented. |
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30.21 The Future of Traditional Safety |
Traditional safety is not going away. It is evolving. New devices are more capable. New controllers are more flexible. New standards are more comprehensive. The trend is toward integration. Safety devices are becoming part of the robot's control system. They are becoming smarter. They can distinguish between a person and a part. They can predict a collision. They can slow the robot instead of stopping it. |
The trend is also toward collaboration. Traditional safety is being combined with collaborative safety. A robot may have a fence around its high-speed zone and a collaborative mode in its low-speed zone. A mobile robot may have a protective field for safety and a warning field for efficiency. The combination provides both safety and productivity. |
The trend is also toward wireless. Wireless safety devices are becoming available. They can reduce wiring and increase flexibility. However, they must meet the same reliability standards as wired devices. They must be secure. They must be resistant to interference. |
The trend is also toward data. Safety devices are generating data. This data can be used to improve safety. It can be used to predict failures. It can be used to optimize the layout. It can be used to train operators. The data is a valuable resource. |
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30.22 A Detailed Summary of This Chapter |
This chapter has explained traditional safety for industrial robots. Traditional safety is based on separation. It uses hard fences, interlocked gates, light curtains, safety mats, edge sensors, area scanners, and safety-rated controllers. These devices create a boundary between the human world and the robot world. When the boundary is crossed, the robot stops. |
The chapter began with a short summary. It then explained why traditional safety still matters. It described the core principle of the protective stop. It described each of the main devices in detail. It gave examples from many industries, including automotive, electronics, food and beverage, logistics and warehousing, pharmaceuticals and healthcare, agriculture, and construction. It explained the limits of traditional safety. It explained how to design a traditional safety system. It explained the importance of training and procedures. It explained the relevant standards and regulations. It explained common mistakes and how to avoid them. It explained the future of traditional safety. |
The key points are as follows. First, traditional safety is proven, accepted, and cost effective. Second, traditional safety is based on reliable devices and fail-safe design. Third, traditional safety requires a risk assessment and a systematic design process. Fourth, traditional safety requires training and procedures. Fifth, traditional safety is governed by standards and regulations. Sixth, traditional safety has limits, especially in unstructured and collaborative environments. Seventh, traditional safety is evolving and will remain a foundation for robot safety. |
For the reader who is new to robot safety, the most important takeaway is that safety is not an add-on. It is an integral part of the robot system. It must be considered from the beginning. It must be designed, installed, validated, and maintained. It must be understood by everyone who works with the robot. Traditional safety is the starting point. Collaborative safety is the next step. Together, they provide the foundation for a safe and productive workplace. |
cs@easiersoft.com