Mobiler Roboter AGV in Produktionsumgebung mit Werkstückträger und Sensoren zur Detektion und Navigation

Safety and transportation path safeguarding for mobile robots and AGVs

Safety at work is a key area of application, particularly for mobile robots and autonomous guided vehicles, due to their autonomous movement. This applies both to the area immediately surrounding the vehicle and to transfer and interaction zones. Being able to flexibly adapt safety zones to varying operating and environmental conditions is of crucial importance here.

Since people can cross the path at any point, high safety requirements must be met along the entire route. Reliable area safeguarding for mobile robots is often achieved using safety laser scanners. They enable the vehicle’s surroundings to be monitored in compliance with standards and thus make a significant contribution to ensuring safety at work for mobile robots.


Personal safety and safety along the route

As the automation of industrial workflows increases, it is becoming increasingly important to ensure safety at work and the protection of people. The basis for the design of safe machines and systems is a systematic risk assessment where potential hazards are identified and evaluated. Numerous standards and regulations must be taken into account in this process. The EN ISO 13855 standard is particularly relevant for calculating the required safety distance, as it specifies the positioning of protective devices with regard to people’s approach speed.


Sensor applications in detail

Sicherheitslaserscanner RSL  mit Navigation auf Fahrerlosem Transportfahrzeug im Lager mit Sensoren zur Fahrwe

1. Safeguarding the transportation path and navigation

Requirement:

If the principle of natural navigation is used, the safety sensor should provide the measurement data for the navigation software in order to determine the environment in addition to safeguarding the transportation path in different driving situations.

Solution:

The RSL 200 / RSL 400 safety laser scanner merges safety technology and high-quality measurement value output (navigation) in a single device. It features up to 100 configurable and switchable field pairs. The measurement data have a high angular resolution of 0.1° or 0.2°, which allows a very accurate map of the environment to be created for autonomous vehicles. Alternatively, a device solely for navigation would suffice.

Sicherheitsloesung einer Uebergabestation von FTS auf stationaeren Roboter mit dynamischer Schutzfeldanpassung bei Durchfahrt mit Sicherheitslaserscanner RSL

2. Safeguarding of the transfer station

Requirement:

The hazardous area of the robot and the working range of the transfer station must be safeguarded against entry by persons during the entire process. The vehicle must be able to enter and exit the working range fully automatically.

Solution:

As a safety solution, the entire area of the transfer station is safeguarded with RSL safety laser scanners. Their protective fields detect the entry and presence of persons. When an AGV passes through, its outline is dynamically detected and hidden from the protective fields. This allows the AGV to automatically enter the station, transfer the material at the parking position, and then leave the station again. This means that the station remains as safe as can be at all times.

> More about Safety Solutions

Kompakte Sicherheitssteuerung MSI zur Integration und Auswertung sicherheitsrelevanter Daten des Fahrzeugs

3. Safety function on the vehicle

Requirement:

A safety controller is used to record and monitor safety-related parameters such as velocity, steering angle and other driving status data to ensure that the AGV/AMR is functionally safe and operates in a way that is safe for personnel.

Solution:

The compact and modularly expandable MSI 400 safety controller enables safety-related functions to be programmed intuitively and without a license, with the integration of multiple safety sensors. This makes it particularly well-suited for mobile robots or AGVs.


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Frequently asked questions about safety and mobile robots

To prevent collisions, distance sensors arranged in the direction of travel are used to detect approaching obstacles and, if the distance falls below a defined safety threshold, trigger a signal to bring the AGV to a controlled stop. At very low travel speeds, safety can be further ensured by bumper contacts, which bring the robot to an immediate stop in the event of a collision.

The type of movement and the robot’s operating environment are decisive factors when it comes to selecting appropriate safety measures. Linear movements, for example, can be safeguarded by guards such as safety fences or non-contact protective devices (e.g. light curtains). Freely moving autonomous mobile robots (AMRs), on the other hand, must be equipped with sensors for area monitoring. In particular, measuring protective devices, such as safety laser scanners, are used for this purpose; these detect obstacles and people in the robot’s path and ensure a safe response from the robot.

To prevent collisions, the AGV is equipped with measuring sensors aligned in the direction of travel. These sensors detect obstacles in the travel area and trigger an automatic braking response when an obstacle is approached. At very low travel speeds, protection can alternatively or additionally be provided by bumper contacts, which trigger an immediate shutdown of the robot upon physical contact.

To ensure safe navigation and collision avoidance, the environment around the AMR, AGV or AGV system — at a minimum, the area in the direction of travel — is continuously monitored using measuring sensors. This allows for both obstacles and people to be detected within the travel area.

To minimize unnecessary downtime, software-based safety fields or detection zones are defined, and any objects detected within these areas are evaluated for their relevance to operation. The system typically responds in several stages, depending on the detected distance: In stage one, the travel speed is reduced and a warning signal is issued. If the distance falls below a critical safety threshold, the vehicle is automatically brought to a stop as part of stage two.