Control technology drives innovation

The result is a gantry robot design that can be easily adapted to different line layouts, which is robust, reliable and compact, and which above helps to minimise downtime.

The palletiser was built around a slim H-bridge for the gantry motion, ensuring the gantry could be kept as light as possible and with a minimal footprint. To this is fitted a telescopic mast for the Y-axis, with a gripper arm on the end. Use of a telescopic mast ensures that overall height of the palletiser is minimised.

Two servo motors drive the belts of the H-bridge, while a linear servo motor is fitted to the telescopic mast for the Y-axis. A direct drive servo motor on the gripper arm provides 360° rotation.

At first the control solution for this conceptually simple yet technically sophisticated palletiser seemed elusive, until New Motion turned to Omron through engineering services specialist Denissen Engineering. Ronald Dekker, responsible for engineering at New Motion explains: "We decided to use a direct drive motor because due to their design, there is no gearbox, which ensures there are no oil or grease spillages on the product. Also this reduces the overall weight, making the grab-arm more energy efficient and ultimately reduces cycle times.”

"But controlling a direct drive motor poses a problem in that most suppliers only offer fixed servo motor and drive combinations. But when we turned to Omron, they suggested incorporating the company’s servo drive with a third party direct drive motor, which meant simplified programming and commissioning. Additionally, Omron were also able to deliver the other control components, including servo drives, servo motors, PLC and HMI.”

In the new palletiser, all of the servo axes are controlled by Omron Accurax G5 compact servo drives with built in EtherCAT. Sequence control and motion profiles are provided by an Omron NJ machine controller, connected to the Accurax G5 servos via high speed EtherCAT link. Central to Omron’s Sysmac integrated automation platform, the NJ controller offers synchronous control of all machine devices.

A load cell in the gripper arm feeds data back to the NJ machine controller, monitoring weight anomalies that could be indicative of problems that would lead to stacking or loading issue, and so eliminating a potential cause of downtime.

The operator interface is provided by an Omron NA series HMI, which Dekker argues offers important user benefits on the machine. "The HMI makes the machine very easy to operate,” he says. "For example, operators can watch instructional videos directly on the HMI. Also, the HMI provides pictograms and wizards for pallet selection and loading, allowing operators to define and save their own stacking patterns.”

The control software for the palletiser was developed using Omron’s Sysmac Studio programming environment. With this integrated software providing a single environment for programming the controller, HMI and servo drives, New Motion engineers were able to complete the programming process just six weeks after the development of the initial palletiser concept.

A further innovative feature that will benefit customers is the ability for remote diagnostics over Ethernet, enabling New Motion service engineers resolve any control problems quickly.

New Motion introduced the innovative gantry palletiser robot at an international packaging exhibition, where it received great interest. With a capacity of 200-1000 boxes and the ability to work at speeds up to 360 boxes per hour, the new machine is ideal for a wide range of palletising applications.

Since its introduction, the machine has been running continuously and flawlessly stacking more than a million boxes without a single issue, providing ample demonstration of the robust and reliable design. New Motion sales manager Rubert Remijn comments: "We have high expectations for the new palletiser. Compared with existing gantry designs it is more compact, more reliable and more precise, while compared with an articulated robot it is a more cost-effective, compact and energy-efficient solution.”