To do so, however, they need to bring a lot to the table – they must be intelligent, robust, and maneuverable; they must be able to transport high loads; and, of course, they need to guarantee the safety of everyone in the surrounding area. This also places high demands on the drive technology used in these AGVs.
In order to bridge the gap between automated warehouses and automated Production departments, Magazino has developed the mobile logistics robot SOTO (Fig. 1), which intelligently handles and transports SLCs (small load carriers) in warehouse and production environments. The special feature of this robot is that it takes SLCs from passive shelves (i.e., shelves without any conveyor elements) as from heights of 400 mm (Fig. 2).


Fig. 1a,b: The mobile logistics robot SOTO from Magazino bridges the gap between automated warehouses and automated Production departments. It takes SLCs from passive shelves. (Images | Magazino)
In total, it can transport up to 24 SLCs (300 x 200 / 400 x 300 / 600 x 400 mm) with a maximum payload of between 200 and 249 kg. With a transport height of 2160 mm and a virtual footprint of 2500 x 1310 mm, the robot fits through aisles with a width of 1650 mm. It can be deployed by itself or as a fleet in both brownfield and greenfield applications. SOTO brings materials directly to the assembly line according to the just-in-time principle. Its built-in “intelligence” enables it to complete transport tasks independently, even complex ones, and react flexibly to changes in the surrounding area or changing requirements. It can completely replace tugger trains or work effectively with them. SOTO is typically deployed in automotive and electronics production environments or around injection molding equipment, for example.
200-249 kg
payload
24
SLCs
2160 mm
transport height
When developing the mobile robots, the experts invested a lot of time in selecting, thoroughly testing, and comparing potential drive units. The second version of the robot is now available, and it relies on the ArgoDrive driving steering drive from ebm-papst because it was the best at meeting the various application requirements (Fig. 3).
ArgoDrive: the driving steering system for AGVs
Thanks to its innovative combination of drive and steering motors, the ArgoDrive enables precise omnidirectional movement, making automated guided vehicles highly maneuverable. (Video | ebm-papst)
A flexible and robust drive
Warehouse logistics areas and production environments both have one thing in common: Space equals money. When it comes to autonomous robots, this means that they have to navigate flexibly in tight spaces. This, in turn, calls for drive units which enable the robot to make omnidirectional movements (Fig. 4). With ArgoDrive, each drive unit consists of two brushless DC motors, transmission, the corresponding safety sensors, and all the necessary connection plugs. Thanks to a superposition gear, the two motors contribute to steering, driving, acceleration, or braking, depending on what is required at the time. This gives the robot an infinite steering angle which enables it to make omnidirectional movements, even from a stationary position. As a result, the mobile robot can navigate safely in tight spaces, move to the exact pick-up and set-down positions, and make adjustments on the spot to ensure accurate positioning (e.g., when entering the charging station). In addition, the driving steering system ensures that the available space is optimally used and that the robot can flexibly avoid people or other vehicles in tight spaces.
Robustness was another key requirement because components that are installed in a moving environment are always exposed to vibrations and other forces. All the necessary connecting cables of the drive unit are therefore permanently fixed in place, which prevents annoying problems with the contact points while the robot is in use. Weak contacts are currently the number 1 reason why automated guided vehicles fail.
Compact design

Magnus Eldevik (Fig. 5), Product Marketing Manager at Magazino, is delighted with the drive’s compact design: “Because ArgoDrive has such a flat design, we have achieved a low gripping height of just 400 mm, ensuring that expensive storage space can be used as efficiently as possible. Compact drives also mean more space for grippers or the payload – and the higher the payload, the more efficient the mobile robot ultimately is.” The driving steering system is available in different models: Light (up to 100 kg capacity), Standard (up to 300 kg), and Heavy (up to 500 kg). All models have a drive housing measuring 250 x 170 mm (length x width), while the height varies between 103 and 205 mm depending on the model.
Safe interaction with others
Safety is paramount if mobile robots share the space with people and other vehicles – it is crucial that the robots reliably detect obstacles around them. If the protective zone is breached, they must ensure sufficient braking power is provided. They must also ensure that the stop command issued by the safety controller is executed reliably. In this context, the developers of the mobile robot value the fact that, as standard, ArgoDrive supports various safety functions for safe operation of automated guided vehicles (see technology box). All safety indicators that are relevant for safety certifications, such as MTTFd and B-10 values, are available to ensure compliance with the requirements set out in the AGV standards ISO 13849 and ISO 3691-4.

Because ArgoDrive has such a flat design, we have achieved a low gripping height of just 400 mm, ensuring that expensive storage space can be used as efficiently as possible.
Magnus Eldevik, Product Marketing Manager at Magazino
Simple integration
The logistics robot SOTO can be easily integrated into a wide range of controller systems thanks to standardized communication and safety interfaces such as CANopen, EtherCAT, or Profinet. For the safety controller, the developers at Magazino opted for a solution from the company SICK. They also chose an industrial PC to control the vehicle. Among other things, this controls the ArgoDrives using the ebm-papst drive controllers. Eldevik comments: “We benefited greatly from the excellent support provided by ebm-papst here. As beta testers of the drives, we were in regular contact with the manufacturer. Both sides benefited greatly from this in-depth and enjoyable collaboration.”
Drives for the lifting movement and grippers
Another reason to choose the drive for this application was its high degree of efficiency, which enables a 5:1 ratio of operating time to charging time (i.e., 8 hours of operation with approx. 1.5 hours of charging). A further advantage is the green brake function, which significantly reduces the energy demand compared to other brake actuation concepts by lowering the energy consumption when the brake is released. Eldevik adds: “Of course, we also found it very useful that ebm-papst offers a wide range of drives which we can use for other things, such as ECI motors for receiving SLCs, i.e., for tipping movements in the storage unit. The fact that we can work with different drives from the same manufacturer throughout the mobile robot naturally makes the interfaces much easier for us.” Magazino is pleased with the quality of the drives used and the enjoyable cooperation, and can certainly see itself collaborating on other joint projects in the future.
Ruling out collision risks
Safety is a key issue when operating mobile robots and automated guided systems. If the working environment of personnel overlaps with the routes of the AGV, collision risks must be ruled out. ArgoDrive offers several options for this. If the protective zone is breached, for example, the drive system must reliably execute the command for a safe stop issued by the safety controller. Above all, a high level of brake power must be available for the drives. Here, the ArgoDrive achieves deceleration of up to 2.5 m/s2 using the electric motor brakes, and emergency braking is also possible using the additional integrated mechanical brake. In order to prevent uncontrolled movements, the drive unit also comes to a safe stop if the AGV power supply fails. As a result, the drive supports all typical and necessary safety requirements that apply to warehouses and production environments.
For this purpose, the individual driving steering system is actuated by two external controllers. The signals for the steering angle are also designed with redundancy and the position can be queried at any time. The STO function (Safe Torque Off) integrated into the controllers ensures a safe stop (PLe). STO and, if necessary, the emergency stop function of the mechanical brake can be triggered together. In addition, the drive monitors that a defined maximum speed is not exceeded (SLS, Safe Limited Speed) and the vehicle only moves in the permitted direction (SDI, Safe Direction). To ensure this, both motors integrated in the ArgoDrive have two independent feedback systems as standard: The integrated hall sensors for commutation and the high-resolution incremental encoder for closed-loop control. By comparing both signals, the electronics can record the speed of the motors while ensuring functional safety.
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