1. Key Safety Functions of AGV Safety Control Systems
With the increasing demand for AGV applications, many excellent AGV manufacturers and suppliers providing related solutions have emerged both domestically and internationally. The ISO 3691-4 standard, specifically addressing the safety of unmanned industrial vehicles and their systems, was officially released and implemented in 2020, filling a gap in industry standards.
ISO 3691-4:2020, while continuing the technical framework of EN 1525, further improves the safety architecture, expands the safety functional requirements, and sets higher requirements for the safety control system and usage scenarios of AGVs. The items covered are more detailed, specific, and comprehensive. The new standard specifies the safety requirements for the work area to ensure the safe operation of trucks.
(1) Work area
A clearance space of at least 0.5 meters wide and 2.1 meters high should be provided on both sides of the AGV travel path. This clearance space is measured between the AGV travel path and adjacent fixed structures along the path.
(2) Hazardous work areas
Areas with insufficient clearance or where personnel monitoring methods cannot provide protection are designated as "hazardous work areas" and marked accordingly. Hazardous work areas should be clearly marked with appropriate signs or floor/ground markings to avoid confusion with other signs and markings.
In this hazardous work area, the truck speed should comply with the requirements of Tables A.1 and A.2 in the standard, and the truck should emit additional audible and/or optical warnings.
If there is insufficient clearance and no pedestrian escape route at least 0.5 meters wide and 2.1 meters high, a personnel detection system should be activated to ensure that the area within 180 mm of the edge of the ESPE safety zone and surrounding objects can be detected to check for personnel in that area.
(3) Restricted Area
Areas with insufficient clearance and which cannot be protected by personnel detection systems should be designated as "restricted areas" and marked accordingly.
The following measures should be taken in restricted areas:
A. The area is clearly marked with signs and floor/ground markings;
B. Only authorized personnel who have undergone specific hazard training are permitted to enter the area;
C. The area must not contain any workplaces;
D. The area shall be equipped with fixed protective devices conforming to ISO 13857 and ISO 14120, and the height of the protective devices shall be at least 2.1 meters;
E. The area should be equipped with movable protective devices (doors) to provide access for authorized personnel.
(4) Enclosed area
An area that can be shielded from personnel detection systems and allows AGVs to operate at any speed should be designated as a "closed area" and appropriately marked. The closed area should implement the following measures:
A. The area is clearly marked with signs and floor/ground markings; B. Access to the area is limited to authorized personnel only;
C. The area must not contain any workplaces;
D. The perimeter of the area shall be equipped with fixed protective devices conforming to ISO 13857 and ISO 14120, and shall be at least 2.1 meters high;
E. The area should be equipped with a movable interlocking security device (door) with a protective locking function to provide access for authorized personnel.
(5) Loading and unloading area
Loading and unloading operations should only be carried out in designated locations and truck positions within this area. If the design of the loading and unloading area does not prevent personnel injury, this area should be considered a hazardous work zone.
The new standard also lists the following table regarding the clearance space on both sides of the AGV's travel path, the start and stop of the personnel detection system, the maximum operating range of the AGV, and the division of areas. This is to enable AGVs to operate more efficiently and safely within the factory, and to help factory employees better avoid unnecessary safety accidents involving AGVs.
2. Safety Laser Scanner: The Leading Role in AGV Safety Protection
Safety laser scanner work site
Safety laser scanners, used to detect personnel or objects in the path of AGVs, provide safety during high-speed AGV operation without affecting production efficiency, protecting both people and goods. Pilz's PSENscan safety laser scanner boasts a scanning angle of up to 275 degrees and a protected area width of up to 5.5 meters. Not only can warning and protected areas be freely configured, but it also possesses superior environmental adaptability, making it ideal for integration into AGV safety control loops, and particularly suitable for monitoring and protecting multiple areas.
Pilz Safety Laser Scanner PSENscan
In practical applications, two PSENscans can achieve 360° all-around safety protection. During the AGV's movement, the PSENscan can flexibly switch to the appropriate protection zone or warning zone according to the current travel path, ensuring safety even when the AGV is turning. At the same time, the PSENscan can also measure the distance to objects in the environment, and this information can be used for direct navigation of the automated guided vehicle.
