Full throttle for intral­o­gis­tics: drives for shuttle vehi­cles

The same applies to shuttle appli­ca­tions as to all intral­o­gis­tics: the faster the vehi­cles can accel­erate and brake, the higher the throughput rate and the more goods can be picked or supplied. Accu­racy when driving up to the storage loca­tions and handling the prod­ucts or product carriers is also an impor­tant require­ment for this, as is reli­a­bility, because if the hard-working vehi­cles fail, the ware­house processes come to a stand­still.

Tough require­ments for the drives

Drives that ensure that shut­tles move in a targeted manner within the shelf systems play a key role here. For example, the one – or some­times two – trac­tion drives must be dynamic, accu­rate and robust for the move­ments in the direc­tion of the x-axis and it must be easy to inte­grate them into the appli­ca­tion. The latter not only applies to the drive’s dimen­sions, but also to its connec­tion to the vehicle’s control system. The tele­scopic drives for the pick-up device that removes the goods from or adds them to the shelf is just as impor­tant for smooth shuttle oper­a­tion.

Here, there is often even less instal­la­tion space for the neces­sary motor-trans­mis­sion combi­na­tions than there is for the trac­tion drive. In some types of ware­house, shut­tles do not only travel in one direc­tion, they can also travel across the ware­house. This requires similar drive concepts to the trac­tion drive, in some cases with much more compact dimen­sions.

Fig. 1: In the Modular drive system, all indi­vid­u­ally selected drive compo­nents are placed in a common housing. (Graphic | ebm-papst)

Manu­fac­turers are well-advised to find a motor manu­fac­turer that can give them skilled support in selecting a motor and that has a broad range. Drive solu­tions from a single source not only provide logis­tical bene­fits, they usually simplify coor­di­na­tion and shorten the time to market. That is why ebm-papst offers a wide selec­tion of motors, control elec­tronics, trans­mis­sions, and brake and sensor modules that can be combined to create a tailor-made drive (Fig. 1).

The elec­tron­i­cally commu­tated ECI motors, for example, cover a contin­uous power range from 30 to 750 watts in sizes 42, 63 and 80 mm. Then, different trans­mis­sions matched to the drives ensure the neces­sary reduc­tion ratio of the high-speed internal rotor motors. The trans­mis­sions can also be combined with the external rotor motors in the VDC series.

The latter cover a power range of 5 to 125 watts in the smallest instal­la­tion space and also boast a long service life and good control prop­er­ties. The modular drive system offers several thou­sand vari­ants in total. Defined preferred types are ready for ship­ment within just 48 hours, making them avail­able for sampling excep­tion­ally quickly. In addi­tion, the motor and trans­mis­sion special­ists offer project-specific engi­neering, e.g. when it comes to fine tuning the motors or special trans­mis­sons and when adap­ta­tions to the overall length, cable assembly or addi­tional encoders are required.

Dynamic trac­tion drives

The modular drive system enables stan­dard solu­tions to be imple­mented for many appli­ca­tions. For example, the ECI internal rotor motors are ideal for use as shuttle trac­tion drives, depending on the required power, either in size 63 or 80 (Fig. 2). They require little instal­la­tion space, achieve high torques at 24 or 48 V, and are able to deliver three times the nominal power for a short time. Combined with the Optimax trans­mis­sions, which already have over­load capacity, compact, robust drive systems are created, which can also be controlled based on the appli­ca­tion through the motor elec­tronics chosen.

Fig. 2: The ECI internal rotor motors, for example, are ideal for use as shuttle trac­tion drives. (Graphic | ebm-papst)

The K1 elec­tronics module is designed for oper­a­tion with external control elec­tronics. If the drives are to commu­ni­cate via CANopen, EtherCAT or other common BUS systems, the K5 elec­tronics module is the right choice. It can have an external or inte­grated design. Config­urable, inte­grated control elec­tronics for speed, torque and posi­tion are avail­able for analog actu­a­tion.

The plan­e­tary gears in the Optimax series also have a high power density and are also very robust and durable. Another special feature of the trans­mis­sion series is the high torques. The medium variant, for example, offers peak torques of up to 150 Nm with an instal­la­tion edge dimen­sion of 63 mm and a length of just 102 mm in the two-stage version.

Bespoke tele­scopic drive

In the shut­tles, space for the tele­scopic drive is usually at a premium. This is a typical area of appli­ca­tion for the VDC 49.15 external rotor motor (Fig. 3), for example.

Fig. 3: The VDC 49.15 external rotor motor is an ideal tele­scopic drive. With a power of 110 W, it is just 52 mm long with a diam­eter of 63 mm and can be easily combined with the robust Optimax plan­e­tary gear. (Graphic | ebm-papst)

With a power of 110 W, it is just 52 mm long with a diam­eter of 63 mm and can also be easily combined with the robust Optimax plan­e­tary gear. This compact design means that one drive can be used per tele­scopic arm, thus two drives per tele­scope, which massively increases the power density of the shuttle and the throughput rate of the ware­house. It is also possible to adapt the trans­mis­sion design, with the appro­priate number of units.

Fig. 4: The compact tele­scopic drive exhibits impres­sive results. (Graphic | ebm-papst)

The test stand proves what this type of tele­scopic drive can achieve. All shuttle drives can be tested before they are used and the profiles required for the appli­ca­tion can be run off. If neces­sary, the values then form the basis for fine tuning, as the motors can often do far more than what it says on the data sheets. In any case, the tele­scopic drive described above delivers impres­sive results on the test stand (Fig. 4).

In combi­na­tion with a two-stage Optimax plan­e­tary gear, a drive unit delivers a torque of 10.5 Nm to the output shaft. There­fore, the tele­scopic mech­a­nism can move 50 kg cargo load with an accel­er­a­tion of 1.1 m/s².

A drive solu­tion like this is also recom­mended if the width of the gripper system has to be adjusted to adapt it to different product carriers. If there is no stan­dard solu­tion, the motor and trans­mis­sion special­ists can help with the selec­tion and engi­neering.