Three dimensional mechanical handling system

Quality componentry has given Austrian design engineers Schuster Messtechnik the confidence to develop a second generation, high performance version of its apple packing robot.

Quality componentry has given Austrian design engineers Schuster Messtechnik the confidence to develop a second generation, high performance version of its apple packing robot.

The original robot used a three dimensional mechanical handling system base on Hoerbiger-Origa linear actuators to present individual apples to a vision system for inspection, orientate them and precision place them into packing trays.

The Mark 2 robot now works at higher speeds, packs three trays at once, has a more flexible handling system that can happily accept different sizes of packing tray, has an all stainless steel construction and an uprated vision system.

Retail psychologists have long known that visual appearance is one of the key purchasing criteria for fruit on supermarket shelves.

In fact the best way to create a good impression with shoppers is a good fruit display, which is why they are always at the entrance to the supermarket.

Recent research has shown that making the effort to pack apples so that their best side is on show increases sales further, as does the practise of positioning all the stalks to point upwards and away from the shoppers at exactly the same angle.

Supplying supermarkets is a competitive business and such are the volumes of throughput that any saving in operating costs will quickly multiply up to being highly significant.

This has allowed Austrian engineer Hermann Schuster to build a successful business on driving efficiency into fruit handling operations.

The machine works in several discrete stages.

Apples are delivered via a conveyor and each is individually picked up by a suction cup on a belt-driven actuator, then an air stream is used to rotate the apple until the stalk stands vertically upright.

Next comes Apfelrobo's core function: the apple is rotated through 360deg under the watchful eye of the vision system, which is looking for the best side.

This is determined in real time and the apple rotated, backwards or forwards, as it is transferred and lowered onto the packaging pallet.

In fact over 100 different images of each apple are analysed in less than 500ms before the best side is decided upon.

For absolute perfection the stalks of all the apples are arranged to point backwards, away from the final customers' viewing position in the supermarket Apfelrobo finally packs the filled pallets into boxes and places them onto an exit conveyor belt to continue their journey to the high street.

All movement axes are based on Hoerbiger-Origa OSP-E electric linear drives.

In this case belt drive models are used in preference to ballscrew units because their robust construction requires minimal maintenance.

High speed and precision was required of the drive axes, as throughput is high.

Similarly the vision system was required to work in real-time, as no delays could be tolerated.

In fact the inspection rotation of the apple, the analysis to determine its best aspect and subsequent rotation to its final position has to be under taken in under 500ms.

The reliability of the OSP-E cylinder is unmatched in the marketplace.

Its long service intervals make a significant contribution to the economic efficiency of the machines' operation.

The basic principals for Apfelrobo were established with the original machine design, while development of a second generation has allowed enhancements in several areas that have taken overall performance to an even higher level.

For instance Hoerbiger-Origa engineers worked hard to redesign the handling system so that it could automatically adapt to different sizes of packing tray.

They were also able to find more secure ways to hold each apple (without damaging them) so that they could be processed at high speeds.

Finally the ergonomics of the machines lay out was rethought so that a single operator can comfortably over see the operation of four machines.

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