How An XYZ Gantry Robot Is Used In A Shop in Italy?

Retail Picking Gantry Robot: A Wall-Mounted XYZ Project for a Shop in Italy

Author: ShanGong, Director of Engineering Department | Published: September 29, 2026 | Category: Projects

Most of the gantry robots we build end up in factories, bolted to machine frames above conveyors and fixtures. This one went into a small retail shop in Italy. It hangs from the walls about two and a half metres above the sales counter, picks packaged goods off floor-to-ceiling shelving, and hands each order to a delivery compartment that opens automatically on the customer side.

The client designed the retail workflow and integrated the rotary base, suction gripper, vision and order system. We supplied the motion platform: a four-axis retail picking gantry robot built from belt-driven linear modules, with servo motors, planetary reducers and sensors. This article follows the project from the first enquiry in October 2022 to the client’s on-site tests, and it covers the one change the client asked for after installation. The client is not named here, and the shop’s product brands are not discussed.

What the Shop Needed the Retail Picking Gantry Robot to Do

The picture that emerged from the client’s drawings and test videos is a counter-service shop turned into a self-service point. An order is placed at the front of the shop. The client’s software identifies the product and its shelf position, and a camera confirms the pick. The gantry then travels to the shelf, lifts the pack with a suction cup, turns it towards a short conveyor belt and releases it. The belt carries the pack to a pickup compartment in the shop front, where a door opens once the item arrives.

Three features of that job shaped every engineering decision that followed:

• The loads are light and the moves are long. Individual packs are light, but the robot has to cover a room about 4 m by 3.8 m and more than a metre of shelf height.
• There is no machine frame to mount on. The only rigid structure in the room is the building itself, so the axes had to be carried by the walls.
• People work underneath it. Staff still stand at the counter, so the robot has to stay overhead and out of the way whenever it is not picking.

Figure 1. Client layout: four-axis linear robot installed 2,500 mm above the floor and fixed to a reinforced concrete wall with six flanges.

The Client’s Brief data to expect for a Retail Picking Gantry Robot

The first enquiry arrived on 13 October 2022 as a complete specification rather than a loose request. The client listed the axes, the strokes, the drive type and even the bill of materials they expected. They also said plainly that the system would work at low speed with a light gripping load, so no special performance was required. That candour made the job easier, because it told us where the design margin should go: into envelope, mounting and reliability rather than speed.

Two differences between the request and the supplied system are worth explaining, because a buyer planning something similar will meet the same questions.

Stroke is not the same as module length

The client quoted working strokes. A belt module is always longer than its stroke, because the carriage, the drive end with its pulley and motor mount, the idler end and the over-travel margin all need room. That is why the X modules are 4,100 mm long for a 3,600 mm stroke and the Y module is 3,690 mm long for a 3,400 mm stroke. In a room this size, those extra millimetres decide whether the frame fits between the walls, so the module lengths had to fit inside the client’s maximum installation width of 3,800 mm and length of 4,000 mm.

Two synchronized X motors instead of a cross-shaft

The brief asked for a double X axis joined by a mechanical synchronization shaft. That is the classic way to keep both ends of a bridge moving together, and it works well on compact gantries. Across a span of more than three metres, however, the cross-shaft becomes a long rotating part of its own. It needs intermediate support, it winds up slightly under acceleration, and it has to cross the room overhead. The final order therefore gave each X module its own 400 W servo, with the two drives synchronized electronically. The bridge still moves as one piece, but nothing spins across the ceiling.

Figure 2. Front and side views from the client’s drawings. The suction tube reaches 450 mm from the rotary base, and the side view shows the hand-off to the conveyor belt.

Designing Around a Room Instead of a Machine

In a factory cell the gantry frame is the reference. Here the reference was a concrete wall. The client’s layout fixes the robot 2,500 mm above the floor with six flanges anchored into reinforced concrete. That height keeps the whole moving structure above head level, and it leaves the Z axis to do all the reaching down to the shelves.

The end of arm adds a second geometric problem. The client mounted an electric rotary base on the Z carriage and a suction tube that reaches 450 mm from the rotary centre. When the base turns, the cup sweeps a circle of 900 mm diameter. That circle has to clear the shelving on one side and the Z axis itself on the other, at every height the robot works at. In practice this means the rotation happens at a safe distance from the shelf face, and the approach to the product is a straight linear move once the cup is already pointing at it. The same logic applies to the conveyor belt on the other side of the move.

Cable management matters more in a shop than on a factory floor, because the cable chains are in plain view and hang over the staff area. Each axis carries its own chain, and the 10 m motor cable sets leave room to place the drives in a cabinet away from the counter.

Factory Assembly and Test for this Retail Picking Gantry Robot

The axes were built on our assembly line and then put together as a complete gantry on a test platform before shipment. Running the full XYZ structure in the factory let us check the motion of the complete robot, including the two-motor X axis, before it left the building. The robot was then packed in a custom export wooden crate for the journey to Italy.

Figure 3. Belt-driven X and Y modules being assembled with their planetary reducers.

Figure 4. The complete XYZ gantry running on the test platform before shipment.

Installation and First Tests in the Shop

On 6 April 2023 the client wrote to say the whole structure was installed, and sent photographs of the robot in the shop. The X modules run along two walls just under the suspended ceiling, fixed with black corner brackets. The Y bridge spans the room between them, and the Z axis drops from the bridge to the level of the shelves.

Figure 5. The gantry installed in the shop, with the X modules along the walls just below the ceiling.

Figure 6. Corner bracket joining the Y bridge to an X module carriage.

The client’s own test videos show the robot doing the complete job. The Z axis travels down beside the shelving, the cup picks a single pack from its slot, and the robot carries it to the hand-off point. On the shop front, the pack arrives in a stainless-steel pickup compartment behind a door that opens automatically.

Figure 7. On-site test: the Z axis working beside the shelving during a pick.

Figure 8. The customer-side pickup compartment. The sign asks customers to wait for the automatic opening.

The Change After Installation: Turning the Z Motor Vertical

In the same email the client raised the only change of the project, which came out of the installation itself. The Z-axis motor was mounted horizontally at the top of the Z carriage, as it had been on the drawings. Once the robot was in the room, that horizontal motor stuck out sideways and took up space the shop needed. The client asked whether the motor could stand vertically alongside the Z axis instead, using a 90-degree gearbox.

Figure 9. The Z axis as first installed, with the motor mounted horizontally at the top of the carriage.

This is a common situation on long-stroke vertical axes, and it is solved by inserting a right-angle gearbox between the reducer interface and the motor. The motor then folds down parallel to the Z module, so the drive package no longer projects across the working area. We returned a revised 3D proposal showing exactly that arrangement, and the client placed a follow-up order for the right-angle gearbox so the Z drive could be rebuilt on site.

Figure 10. Revised Z-axis drive, supplied as a follow-up order: a right-angle gearbox lets the motor fold down parallel to the Z module.

Three points had to be checked before the gearbox was supplied:

• The brake stays with the motor. The holding brake is inside the Z servo motor, so it moves with the motor to the new position and still holds the vertical axis when power is off.
• The total ratio must stay the same. If the right-angle stage adds reduction, the controller’s scaling and speed limits have to be updated, otherwise the Z axis would move by the wrong distance.
• The new envelope must clear everything else. The folded motor now travels with the Z carriage, so it has to clear the rotary base, the suction tube and the shelf edge over the full 1,500 mm stroke.

What This Project Shows About Retail Picking Gantry Robot Automation

Retail picking turns the usual gantry priorities around. Payload and speed were modest, and the 0.2 mm repeatability target was comfortable for belt-driven axes. The difficult parts were all physical: fitting long modules between walls, carrying the robot from the building structure, keeping moving parts above the people who work underneath, and packaging the motors so they do not intrude on a small room.

For anyone planning a similar project, the most useful information to send at enquiry stage is the room itself. The wall material and height, the maximum installation width and length, the shelf layout and depth, the end-of-arm geometry, and where the drives and cabinet can sit all matter. With those in hand, module lengths, motor positions and mounting brackets can be settled on the drawing, before the client has to ask for changes on site.

For the general principles of three-axis systems, see our 3 axis Cartesian robots page, and for multi-axis architecture see the Cartesian linear gantry system overview. If you are planning an overhead picking system for a shop, pharmacy counter or small warehouse, send us your room drawing and shelf layout at info@tallman-robotics.com and our engineering team will propose a configuration.

Want check more projects?