ArgoDrive: a compact and easily inte­grated drive system for a wide range of auto­mated guided systems. (Graphic | ebm-papst)

The usage scenarios for auto­mated guided vehi­cles in the health sector are very complex. Light, sensi­tive and fragile goods must be trans­ported as well as tons worth of medical devices. AGV manu­fac­turers there­fore require differ­en­ti­ated drive systems for the different solu­tions. Fan and drive specialist ebm-papst offers the right solu­tion here with a variety of drive combi­na­tions. With the “ArgoDrive”, a compact and easy to inte­grate driving/steering system including wheel was devel­oped, which can move loads of up to 100 kg, 300 kg or 500 kg per drive axis in the Light, Stan­dard and Heavy versions (Fig. 3). In the maximum expan­sion stage with four driving/steering systems in the Heavy version, it is easy to achieve a load capacity of two metric tons, i.e. even x-ray systems that weigh tons, like a CT scanner, are easy to move.

Compact despite high perfor­mance

The instal­la­tion dimen­sions and the elec­trical, mechan­ical and control inter­faces are iden­tical in all three vari­ants, only the impeller diam­eter (80 mm, 100 mm, 145 mm) and thus the ground clear­ance differ. Thanks to the ArgoDrive’s compact hori­zontal dimen­sions of 250 mm x 170 mm, the AGV manu­fac­turer has enough space to accom­mo­date other compo­nents, e.g. for control systems, safety modules or batteries. This keeps the overall vehicle height low, which meets the require­ments of goods transfer stations or the design of mobile robotics. The ArgoDrive is a safety extra-low voltage drive system (48 VDC), so the require­ment for docu­men­ta­tion is manage­able and commis­sioning is simpli­fied. In addi­tion, the battery voltage can be used directly without a voltage booster and/or inverter. The intel­li­gence inte­grated into the drives also enables condi­tion moni­toring and predic­tive main­te­nance depending on the version.

The Light, Stan­dard and Heavy versions cover load capac­i­ties of 100 kg, 300 kg or 500 kg. (Graphic | ebm-papst)

Each drive unit consists of two motors, trans­mis­sion, sensors and all the neces­sary connec­tion plugs. With the super­po­si­tion gear, the two motors contribute towards steering, accel­er­a­tion, move­ment and braking, depending on require­ments. The infi­nite steering angle enables free-range vehicle move­ment – even from a stationary posi­tion. The use of two driving/steering systems, mounted diag­o­nally on the left and right side of an AGV, guar­an­tees omni­di­rec­tional freedom of move­ment and narrow maneu­vering, e.g. when avoiding things.

Two addi­tional freely moving support wheels on the front and rear provide the AGV with the neces­sary load handling and stability. Depending on the size of the auto­mated guided system and the weight to be moved, three or four driving/steering systems can also be installed. Trans­port solu­tions equipped with the ArgoDrive can move large loads with full func­tion­ality, even on inclines of up to 10 percent. In other appli­ca­tions, it may make sense to use a single drive unit, for example as a maneu­vering aid for hospital beds.

Low-main­te­nance and fail-safe

Reli­able oper­a­tion is an impor­tant aspect for AGVs in all areas of medical tech­nology. Unsched­uled down­times reduce avail­ability, as does main­te­nance being required at regular inter­vals. The drive units are there­fore designed for reli­a­bility for the entire service life. If the wheel surface wears down after a long period of oper­a­tion, a simple “tire change” is possible without removing the drive unit. Nothing gets stuck on the closed wheels. The smooth surfaces of the wheel can be easily cleaned or disin­fected. Contact errors on the elec­trical inter­faces of the drive systems are also no danger because the neces­sary cables and plugs of the driving/steering system are perma­nently installed in the vehicle and tried-and-tested indus­trial connec­tors ensure a safe connec­tion to the control system. In the event of a defect, the entire unit can also be replaced quickly in just a few steps.

The use of two driving/steering systems, mounted on the left and right side of an AGV, guar­an­tees omni­di­rec­tional freedom of move­ment and narrow maneu­vering, e.g. when avoiding things. (Graphic | ebm-papst)

Safe on the move

To protect people, the safety of AGVs is even more impor­tant than reli­able oper­a­tion. The AGV must be able to initiate emer­gency braking imme­di­ately if protec­tive zones are breached in front of the vehicle. Appro­priate safety sensors ensure that the envi­ron­ment is contin­u­ally scanned. If the protec­tive zone is breached, the drive system must give the safety control system the command for a safe stop. Then a high braking power is the main thing required for the drives. Here, the ArgoDrive can enable a delay of up to 2.5 m/s2 using the elec­tric motor brakes, and imme­diate emer­gency braking is also possible using the addi­tional inte­grated brake. In order to prevent uncon­trolled move­ments, the drive unit also comes to a safe stop if the AGV power supply fails. This means that the ArgoDrive supports all typical and neces­sary safety require­ments.

The driving/steering system’s cables and plugs are perma­nently installed in the vehicle and tried-and-tested indus­trial connec­tors ensure a secure connec­tion to the control system. (Graphic | ebm-papst)

For this purpose, the indi­vidual driving/steering system is actu­ated by two external controllers. The signals for the steering angle are also redun­dant and the posi­tion can be queried at any time. The STO func­tion (Safe Torque Off) inte­grated in the controllers ensures a safe stop in the event of an emer­gency. This makes it easy for the AGV manu­fac­turer to achieve further colli­sion protec­tion measures. ebm-papst is happy to help if you have ques­tions relating to the safety of the entire vehicle. Since a drive system for AGVs also has to commu­ni­cate with higher-level systems, connec­tion via CANopen, EtherCAT or Profinet is possible depending on the external controller.

There­fore, the ArgoDrive provides a flex­ible drive solu­tion for AGVs that does not require compro­mises on free-range mobility and compact­ness, whether that is in hospi­tals, phar­ma­ceu­tical produc­tion, reha­bil­i­ta­tion equip­ment or health care appli­ca­tions in domestic envi­ron­ments.