Transport automation columnvol.4
It's too late after AMR is introduced.
"ISO3691-4" - the international safety standard you should know before installing it
table of contents
- Are you familiar with the international safety standard, ISO3691-4?
- What are the risks of introducing "ISO3691-4" without knowing about it?
- General construction process for an AMR system
- We have safety experts on staff. The role of a robot SIer (system integrator) is to ensure safety and security during installation and operation.
- The Importance of Robot System Integrators in Building AMR Systems that Coexist with People
- My Feelings, Then and Now
Are you familiar with the international safety standard, ISO3691-4?
We at IDEC Factory Solutions, a collaborative robotics company, have introduced "ISO3691-4" in several webinars and downloadable materials. We assume that many of you are already familiar with it, but for those who are not, we will explain it again.
The areas where automated guided vehicles such as AGVs and AMRs travel often overlap with worker work areas and walking areas, so ensuring safety is important.
For this reason, the international safety standard C Standard (Individual Machinery Safety Standard) specifies requirements for ensuring the safety of automated guided vehicles and automated guided vehicle systems, just as it does for industrial robots. This is ISO3691-4.
ISO3691-4: Industrial trucks – Safety requirements and verification –
Part 4: Driverless industrial trucks and their systems
This standard summarizes the safety functions that should be implemented in automated guided vehicles and the methods for ensuring safety when operating the system.
The first edition of ISO 3691-4 was published in February 2020, and the second edition was published in June 2. In addition, the first edition of ISO 2023-6 has been standardized as JIS D 3691:4. However, please note that the contents do not completely match as some technical requirements have changed.
Scope of ISO 3691-4:2023
The target is powered automated guided vehicles that are designed for autonomous driving and the automated guided vehicle systems that control and operate multiple of them.
Examples of automated guided vehicles include automated industrial vehicles driven by humans as defined in ISO 5053-1, as well as "AGVs", "AMRs", "bots", "automated guided carts", "tunnel tuggers", and "under carts".
However, this does not apply to vehicles that are guided by mechanical means (rails, guides, etc.) or remote-controlled vehicles that are not considered to be unmanned transport vehicles that must be operated by a human.
List of typical hazards and dangerous events (from ISO 3691-4 Annex B)
Risk assessment is essential to making automated guided vehicle systems safe. It is particularly important to thoroughly identify hazards and events that could lead to serious accidents. This is because if hazards are not identified at this stage, the system will be operated in a way that could potentially cause a serious accident.
ISO3691-4 provides a list of important hazards related to automated guided vehicles and automated guided vehicle systems in Annex B. This list is classified in the same way as the list in Annex B of ISO12100, and allows for the identification of hazards and dangerous events from various perspectives, such as mechanical, electrical, and ergonomic deficiencies. In addition, the measures for hazards and dangerous events are listed with the item numbers in ISO3691-4, and are compiled so that risk reduction measures can be implemented based on risk assessment.
Have you understood the outline of "ISO3691-4"?
Without knowing about "ISO3691-4"
What are the risks involved when introducing it?
So, what risks are anticipated if AMR is implemented without understanding "ISO3691-4"? Let's think about it.
There are some risks involved when introducing AMR without understanding ISO3691-4.
Anticipated risks
- Introducing an AMR that ignores the structure required by standards creates the risk of serious accidents (being crushed by falling loads, being run over)
- Introducing AMRs that do not have the safety features necessary for the intended operation creates a risk of serious accidents (collisions with people) occurring.
- When operating an AMR system, there is a risk that the route and speed will not be set appropriately according to the environment of the route, resulting in a serious accident (collision with a person, a person being trapped between a wall, etc.)
- Unable to implement effective measures against remaining risks, resulting in the risk of serious accidents (collisions with people)
Specific examples of serious accidents
- A general-purpose sensor is used for human detection, and if the device fails, it cannot detect people and may cause a collision.
- A worker's leg is run over by an AMR and fractured.
- A nearby worker was injured when a transported object fell from the AMR and hit him.
- The remaining risk is that a collision with an AMR cannot be avoided due to a person jumping out into the road.
What happens as a result?
- Increased risk of accidents and injuries
Dependence on humans for safe operation increases the risk of accidents and injuries - Reduced productivity and increased costs
Accidents may cause business to stop and lead to lost opportunities
Costly repairs and replacements of damaged equipment and machinery - Risk of legal liability and penalties
The Industrial Safety and Health Act requires that facilities be made safe based on risk assessments, increasing the risk of legal liability in the event of an accident.
Increased risk of criminal penalties, fines, business suspension and litigation
Increased risk of damage to business credibility and reputation
As mentioned above, when operating AMRs in a company's own factories or warehouses, compliance with standards and ensuring safety are essential, so it is essential that those in charge of implementing the system understand the contents of "ISO3691-4" at an early stage before implementation.
General construction process for an AMR system
Now let's look at what knowledge is required at each stage of the system construction process when introducing AMR. The general construction process for an AMR system is as follows:
Steps to implementation
1Clarification of system requirements specifications
● Main contents
・Understanding the characteristics of the transported items (luggage and materials)
- Understand needs such as transport routes, stopping points, number of vehicles, and transport frequency
・Check factory/warehouse layout and human work flow
・Check safety requirements and company rules (whether or not pedestrians and vehicles should be separated, whether or not an alarm is required, etc.)
・Check the possibility of changing facility layout and select the optimal route
・Determine the safety features required for AMR
At this stage, we have not yet reached a point where we can carry out specific risk assessments or designs, but we need to understand the outline of ISO 3691-4 in order to determine the extent to which safety measures are necessary.
2Selection of AMR and concept design of top module
● Main contents
-Compare AMR manufacturers (navigation methods, sensor specifications, etc.)
・Conceptual design of top modules (cart pullers, lifters, conveyors, etc.)
・Define interface requirements with higher-level systems (WMS, etc.)
At this stage, the AMR we are consideringDo the sensor configuration (detecting people in the path), braking system, speed control, etc. meet the safety requirements of ISO 3691-4?This perspective is important.
3Top module detailed design
● Main contents
・Structural and operational design of the top module (work handling section)
・Control sequence, emergency stop and operation interlock design
-Evaluation of contact and pinch risks
This is where risk assessment comes in. ISO 3691-4 requires a safety design for the entire AMR system, including not only the AMR but also the top module and peripheral devices and equipment.
Knowledge of ISO 12100 (the basic standard for risk assessment) and design considerations for control circuits based on the required performance level (PLr) are also required.
4Assembly of transport robot system (manufacturing and assembly of top module, cart, etc.) ⇒ Initial setting
● Main contents
・Parts assembly and wiring
・Initial settings of the control software
- Check the operation of emergency stop buttons and human detection sensors
・Testing bumpers, lights, buzzers, etc.
We check for blind spots in sensors, whether safety equipment is working properly, and whether other factors increase risk.
5On-site delivery, map creation, driving job creation, driving adjustment
● Main contents
・Build a map that matches the actual work environment
- Job linking settings with peripheral equipment and higher-level systems
- Setting deceleration points, waiting areas, and no-entry areas
・Safety checks (risk assessment of human contact, mixing, and the environment)
Create a driving map for the AMR at the actual site and define jobs (transport start and end points, trigger conditions, etc.). Adjust driving routes, priorities, and behavior at intersections.
We then conduct a risk assessment to determine things like setting speed control zones on the map, speed limits and no-entry settings in areas with a large number of people, and procedures for maintenance work.
6System Operation
● Main contents
・Handover and operation training
- Error detection and countermeasures during operation
・Establish a system for inspections and risk reviews
Even after the system is operational, it is necessary to create a safety operation manual for training, conduct regular inspections and keep records, reassess risks associated with software updates and configuration changes, etc. ISO 3691-4 is a standard that is necessary not only when introducing an AMR system, but also during operation.
We hope you found this article useful. By understanding "ISO3691-4" from the design stage onwards, you can use AMR with peace of mind.
We have safety experts on staff to ensure safety and security during installation and operation.
The Role of Robot System Integrators
We have just mentioned the benefits of understanding "ISO3691-4" from the design stage onwards, but it can be difficult to complete the implementation on your own. This is where a robot SIer like us can help.
General role of robot SIer
A robot SIer is a specialized company that supports the introduction and utilization of robots, and plays the following roles:
- Analyzing on-site issues faced by companies considering introducing robots and building optimal robot systems
- Proposal for introduction of the entire system, design, assembly, start-up, etc.
- Providing comprehensive support from robot selection and implementation to operation
- Ensuring the safety of on-site workers and providing after-sales maintenance
Robot system integrators can be broadly divided into two groups: robot manufacturer-affiliated and independent.
- The robot manufacturer group is an SIer business run by companies that handle robots, such as major electronics manufacturers, and specializes in large-scale projects.
- Independent systems integrators are systems integrators that do not have capital ties with major electronics manufacturers, and many of them are small or medium-sized enterprises that specialize in their areas of expertise.
There are the following benefits to using a robot SIer:
- The time required to introduce a robot can be significantly reduced.
- You can get proposals for robot implementation that fit your site's budget and scale
- Consumables will be provided
- You can get personnel who are familiar with robot operation
- Analyze the robot's operation data and receive improvement suggestions
In building an AMR system that coexists with humans
The Importance of Robot System Integrators
As long as it is a collaborative workspace between workers and AMRs, there will be residual risks that cannot be sufficiently reduced technologically.
For AMR, the human detection function is important for preventing contact with workers, but as a safety feature, the vehicle must also stop to avoid contact with obstacles in its path, including stationary workers.
The ISO3691-4 test requires the AMR to stop before colliding with a stationary obstacle in its path, but does not require it to avoid collisions with people approaching the vehicle or jumping out from the side. This is technically impossible to stop, and is the limit of current safety features.
This means that the residual risks for AMRs operating in collaborative workspaces include collisions with workers approaching the AMR or jumping out from the side.
To reduce this residual risk, equipment such as warning sounds and lights on vehicles, visibility of operating areas, and clearly marked driving routes can be mentioned. However, since there is no distinction between humans and AMRs, workers also need to be educated and trained to avoid dangerous incidents.
These efforts must be carried out to ensure optimal operation while promoting risk communication between the equipment manufacturers (SIers, robots) and the equipment operators (users).
My Feelings, Then and Now
The key to achieving both productivity and safety is to design a system that increases productivity while complying with "ISO3691-4." Therefore, it is desirable to work with a robot SIer that is familiar with the standards from the system design stage before introducing AMR.
We have experts in "ISO3691-4" who will support you from design to model selection and installation according to your situation and environment. We will also support you after installation. Please feel free to contact us.
