Autonomous forklifts are getting increasingly good at moving pallets through warehouses and factories without human intervention. They can navigate aisles, recognize obstacles, load trailers, pick loads from the floor or racking, interact with conveyors and respond to instructions from warehouse and fleet management systems.
But there is one warehouse obstacle that presents a very different problem: What happens when an autonomous forklift needs to go upstairs?
For most large, modern distribution centres, the question may never arise. They are typically sprawling, single-level buildings where forklifts and automated vehicles can reach virtually every storage and operating area without changing floors. Multi-story warehouses, older manufacturing plants, urban facilities, and operations incorporating mezzanines present a different challenge.
An autonomous forklift can move horizontally under its own control. To move vertically, however, it has to cooperate with another machine.
That machine might be a conventional freight elevator, a dedicated industrial lift, or a vertical reciprocating conveyor. Whatever equipment is used, autonomous movement between floors requires much more than programming another destination into the forklift’s route.
For the autonomous forklift to work automatically with the lift, they need to talk to each other.
An Old Material Handling Relationship Gets a New Twist
There is nothing new about forklifts interacting with freight elevators. Industrial elevator standards have long recognized applications involving powered industrial trucks. Under the ASME A17.1/CSA B44 framework, Class C freight elevator loading specifically addresses concentrated loads involving industrial trucks. Class C1 covers applications in which the industrial truck itself travels in the elevator, while Class C2 covers situations in which the truck loads or unloads the elevator but does not travel with the freight.
That distinction remains remarkably relevant to automation. An autonomous forklift can potentially drive into an appropriately designed freight elevator, travel to another floor and drive out again. Alternatively, it can deliver a pallet to a lift or conveyor interface, allow the load to travel vertically without the forklift, and leave another autonomous forklift on the destination floor to complete the move. In other words, the basic material handling choices have not changed as much as the technology controlling them.
What has changed is that there may no longer be a forklift operator standing there to press the elevator button, check that the doors are open, make sure the truck fits, select the floor and determine whether it is safe to drive out. All of those decisions have to become part of the automated system.
How Does an Autonomous Forklift Use an Elevator?
In a fully integrated application, an elevator becomes another automated resource available to the forklift fleet. Suppose an autonomous forklift receives an instruction to retrieve a pallet on the first floor and deliver it to production on the third. It picks the pallet and navigates to a waiting position near the elevator. The vehicle or fleet management system then requests the elevator.
Once the elevator arrives, the two systems establish that the lift is at the correct floor, the appropriate door is open, and access is available. The autonomous forklift approaches the doorway and confirms that it can safely enter.
Sensors may be used to verify the position of the elevator car and the available space inside. The truck then drives over the sill and completely onto the elevator platform.
Only after the forklift is correctly positioned can the next sequence begin. The elevator doors close, the lift travels to the requested floor, the doors open, and the autonomous forklift confirms that it has a clear route before driving out.
The elevator can then be released for another task. That sequence sounds relatively straightforward, but it represents a major change from normal autonomous forklift navigation. In an aisle, the forklift largely controls its own movement. At an elevator, it must temporarily become part of a larger automated system.
Research and industry are beginning to formalize that interaction. The M2X project, developed by TU Dortmund University and Fraunhofer IML with VDMA and industry partners, is creating standardized communication interfaces between mobile robots and peripheral equipment including doors, charging systems, load-handling stations and elevators.
Its June 2026 specification includes specific elevator requests covering calling the lift, requesting access, changing floors, exiting and releasing the elevator. It also requires the mobile robot to confirm that it is correctly positioned within the elevator before requesting movement to another floor.
That is a useful indication of where autonomous material handling is heading. The objective is not simply to make individual pieces of equipment smarter. It is to make independently controlled machines understand how to work together.
Autonomous Forklifts Are Already Going Between Floors
The application is more than theoretical. Reeman Robotics describes a three-story luggage manufacturing operation where three autonomous forklifts move materials between floors. According to the company, the trucks communicate wirelessly with the elevator, call it when required, use LiDAR to verify the elevator space, enter the car and continue their journey after arriving at the destination floor. The vehicles reportedly handle loads in the range of 600 to 800 kg.
As a supplier case study, the productivity claims attached to the project should naturally be viewed as vendor-reported results. The more important point is that it demonstrates a working example of an autonomous forklift riding an elevator as part of its normal transport cycle.
There is also another way to solve the problem. VisionNav describes an automated manufacturing and warehousing application where autonomous forklifts operate on different floors, but the trucks themselves do not make the trip. Finished goods headed for second-floor storage are placed onto a conveyor and transferred by a vertical lift. A second autonomous forklift receives the pallet upstairs and puts it into storage.
That approach removes the forklift from the elevator entirely. It also raises an interesting system design question. If pallet movements between floors are frequent, does it make sense to transport a relatively heavy and expensive autonomous forklift every time, or is it more efficient to move only the load and maintain autonomous vehicles on each level? The answer will depend on volume, building layout, equipment utilization and the number of movements required between floors.
Industrial Lifts Provide Another Option
Not every vertical movement system needs to be a conventional freight elevator.
Vertical reciprocating conveyors, commonly known as VRCs, are widely used to move materials between floors and mezzanines. They are material-handling devices rather than passenger elevators and are governed differently. In the United States, for example, VRC manufacturers typically design the equipment around ANSI/ASME B20.1 rather than the passenger and freight elevator code. People are not permitted to ride them.
An unoccupied automated vehicle is another matter. Lift manufacturer Autoquip describes systems designed specifically to integrate VRCs with AGVs and AMRs. The mobile vehicle communicates with the lift control system, requests access and enters the platform. Sensors and interlocks confirm proper positioning before the lift moves, after which the vehicle can exit and continue operating on another level. Other configurations have the autonomous vehicle simply deliver or retrieve the pallet while the lift handles the vertical portion independently.
That flexibility could make dedicated material lifts particularly attractive in facilities being designed around automation from the beginning. Retrofitting an existing freight elevator to communicate with an autonomous forklift may be possible, but a purpose-designed lift can be engineered around the dimensions, weight, controls and traffic requirements of the automated system.
Weight Is Only the Beginning
The physical requirements also deserve attention. An autonomous forklift carrying a pallet can represent a substantial concentrated load. The elevator must accommodate the combined weight of the truck and payload as well as the way that weight is transferred through the forklift’s wheels.
This is one reason Class C elevator loading matters. It does not simply ask whether the total weight is below a number posted inside the elevator. Industrial truck loading creates concentrated forces as the forklift enters, stops and exits. Elevator design requirements account for those loading conditions.
Car dimensions are another obvious consideration. The forklift needs sufficient width and length not only to fit in the elevator but to position itself accurately enough for doors to close safely.
Then there are the finer points of navigation. A human forklift operator can look at a slightly uneven elevator sill, slow down and make an adjustment. An autonomous forklift must detect the situation and respond consistently. Accurate elevator leveling becomes especially important when small wheels, low-clearance autonomous vehicles or sensitive loads cross the gap between the building floor and elevator car.
The old freight elevator and the latest autonomous forklift therefore share a surprisingly basic requirement: the physical interface has to work before the digital interface matters.
Elevators Can Become a Traffic Bottleneck
Perhaps the most interesting problem is not whether one autonomous forklift can use an elevator. It is what happens when several want to use it. An autonomous forklift fleet operating across multiple floors creates a traffic-management problem that does not exist to the same degree in a single-level warehouse.
One truck may be waiting on the first floor to travel up while another is approaching the elevator on the third floor. A third vehicle may have a higher-priority production delivery. Another truck might already occupy the lift.
The elevator has become a shared fleet resource. That means the control system may need to decide which vehicle receives priority, prevent multiple trucks from entering the elevator area simultaneously, manage queues at each floor and reroute vehicles if the lift is temporarily unavailable.
The M2X specification reflects this complexity. Its proposed elevator interface includes not only requests for access and floor changes but elevator status information, capacity management and error handling.
This is where vertical automation begins to look less like an elevator problem and more like three-dimensional traffic control. A system that automates every pallet movement but leaves autonomous forklifts sitting in line for an elevator has simply moved its bottleneck.
Should the Forklift Ride or Should the Pallet Ride?
There may therefore be no single best way for autonomous forklifts to work with industrial elevators. Where moves between floors are occasional, allowing the autonomous forklift to ride a suitable freight elevator could provide considerable flexibility. The same truck can retrieve the pallet, travel between levels, and complete the delivery without another transfer.
For operations with heavy and predictable cross-floor traffic, separating horizontal and vertical transportation may make more sense. An autonomous forklift can place the pallet onto a conveyor or material lift, with another truck receiving it at the destination. The elevator carries only the load instead of repeatedly transporting both the load and the vehicle.
Dedicated VRCs offer another variation, particularly where mezzanines, automated storage systems or purpose-built vertical material flows are involved.
The best solution will depend on throughput, lift availability, travel distance, vehicle utilization, building constraints and the cost of integrating the various control systems. What is becoming increasingly clear is that autonomous forklifts cannot be considered in isolation.
Taking Autonomous Forklifts into the Third Dimension
Warehouse automation has traditionally been easiest to understand in two dimensions. A forklift travels from Point A to Point B, avoiding workers and obstacles along the way.
Industrial elevators add the third dimension. Doing so requires autonomous forklifts, fleet management software, building controls, doors, sensors and lifting equipment to behave as parts of the same material handling system. The elevator must know when the forklift is coming. The forklift must know when the elevator is ready. Both must know when it is safe to proceed.
The challenge has been around for far longer than autonomous forklifts. Freight elevators have been moving industrial trucks and palletized loads between floors for generations. What automation changes is the conversation between them.
The forklift no longer needs someone to push the button. But before it can truly operate across an entire multi-level facility, the autonomous forklift and the elevator have to learn how to talk to each other.
