AMR and Safety: How They Reduce Injuries to Personnel

Material handling is one of the industrial activities with the highest injury rate. Manual lifting, pulling and pushing strain the back and limbs; forklifts, when they share space with pedestrians, are at the root of impacts, tip-overs and often serious crushing incidents. Autonomous mobile robots (AMRs) are not only a productivity tool: they are also a prevention lever, because they remove the operator from the most dangerous tasks and spaces. This article explains, in a technical and neutral way, which injuries AMRs reduce and how, and which standards and functional-safety requirements govern a safe installation.

Typical material-handling injuries

Before talking about a solution, you need to map the risk. The two large families of injury in intralogistics are:

• Musculoskeletal disorders (MSDs) from manual handling: lifting, pushing, pulling and carrying loads cause cumulative injuries to back, shoulders and limbs. EU-OSHA documents how MSDs are among the most widespread occupational health problems in Europe, with a significant weight in lost days and indirect costs.
• Forklift accidents: pedestrian-vehicle impacts, tip-overs (lateral or longitudinal), load falls, crushing when reversing and turning. They are among the most serious events in warehouse and production environments. In Italy, data on injuries from handling and internal transport vehicles are collected and published by INAIL.

The common denominator is the presence of the operator at the point of risk: the body that lifts, the person on foot near a moving vehicle, the driver exposed to tip-over. Reducing exposure is the most effective prevention strategy, according to the hierarchy of safety measures (eliminate the hazard before protecting against it).

How AMRs reduce the risk

AMRs act on both families of injury, each with a different mechanism.

Less manual handling

By automating the repetitive transport of pallets, containers and rolls, the AMR reduces the lifting, pulling and pushing done by the operator. Less manual handling means less exposure to the risk factors of MSDs. The operator shifts from a role of physical force to one of supervision and added value, often with better ergonomics.

Fewer pedestrian-vehicle accidents

Compared with an operator-driven forklift, the AMR eliminates several accident causes at the root: no distraction, no unmanaged blind spots, no forced manoeuvres, no reversing without sensors. Above all, it travels at controlled speed and is equipped with safety laser scanners that monitor the space in front of and around the vehicle. When a person enters the area, the system slows or stops the AMR before contact. Trajectories are repeatable and free of human driving error.

Functional safety: laser scanners and protective fields

The heart of an AMR's safety is environmental perception. Safety laser scanners generate configurable two-dimensional fields around the vehicle. Typically these are defined:

• Warning/slowdown field (outer): when a pedestrian enters it, the AMR reduces speed and signals the presence.
• Stop field (inner): if the person comes closer and enters the stop field, the vehicle halts completely before contact.

These fields are not static: they adapt dynamically to speed and direction of travel, widening at higher speeds and in the direction of motion, because the stopping distance grows with speed and load. Correct sizing starts from the real stopping distance of the fully loaded vehicle, not from theoretical values. Safety laser scanners and other electro-sensitive protective devices comply with the IEC 61496 standard, while the reliability of the safety-related control chain (from sensor to actuator) is governed by ISO 13849-1 through the concept of Performance Level.

The regulatory framework

AMR safety is not left to good intentions: it is standardised. The main references:

The logic flow is clear: you start from the risk assessment (ISO 12100), apply the specific requirements of ISO 3691-4 for driverless trucks, design the safety functions with the required reliability (ISO 13849-1) using compliant devices (IEC 61496), and document everything for the purposes of CE marking under the Machinery Regulation.

Mixed human-vehicle areas

A substantial difference compared with many traditional AGVs is the ability of AMRs to operate in areas shared with people, without physically segregated routes. It is an important operational advantage, but it shifts the centre of gravity of safety onto the design of the environment:

• define speeds consistent with pedestrian density in the different zones;
• manage intersections and crossings with right-of-way logic and, where needed, signalling;
• take care of floor and vertical signage and lighting;
• plan procedures for non-nominal situations (fault, persistent obstacle, blockage);
• separate, where appropriate, high-speed flows from zones with greater human presence.

Near-miss and safety culture

Technology reduces the risk but does not remove the need for a safety culture. AMRs generate valuable data: safety stops, slowdowns, detected obstacles. Treating these events as near-misses — close calls to analyse, not nuisances to silence — makes it possible to identify layout weak points, risky behaviours and the need for redesign before a real injury occurs. Safety is a continuous process, fed also by fleet data.

What to verify in an AMR project

• CE marking of the vehicle and manufacturer's declaration of conformity;
• risk assessment of the application per ISO 12100, not only of the isolated vehicle;
• compliance with ISO 3691-4 and consistency of safety functions with ISO 13849-1;
• sizing of protective fields on the real stopping distances at full load;
• layout and management of mixed areas, intersections, crossings and signage;
• staff training and definition of operating and emergency procedures;
• near-miss monitoring and periodic review of the risk assessment.

To explore available technologies and configurations, see the PITECH industrial automation, robotics and material handling page. The economic side of this choice, with the calculation of ROI, TCO and payback, is covered in the article AMR: how to calculate ROI, TCO and payback. PITECH supports a neutral technical-commercial assessment, verifying with the client risks, layout and regulatory requirements before proposing the safest and most coherent AMR architecture.