FEATURE PLCS, HMIS & INDUSTRIAL PCS
Robot control is changing, with PLC-based solutions offering different benefits and opportunities over the traditional dedicated robot controllers. So what needs to be considered when selecting the right solution? Barry Weller, product manager at Mitsubishi Electric, comments
electing a robot control solution greatly influences the overall machine capabilities, as well as its ease of set-up and operation. Get the choice right and system flexibility can be improved, commissioning simplified, changeover time for operators minimised, and it can avoid compromising performance. By following a few best practices and principles, it is possible to select a control option that meets the requirements of the application whilst maximising productivity and Return On Investment (ROI).
S
PLC-BASED OPTIONS With a number of current PLC or motion control products – such as the Mitsubishi Electric iQ-R – the kinematics to control many different types of system are available. This enables the OEM to design and build a bespoke robotic solution: for example, a 2-axis gantry pick and place or a 4-axis delta arm for packaging. While dedicated robot controllers provide off- the-shelf solutions that are suitable for a wide range of applications, PLC based control options can empower robot integrators to develop their own bespoke systems. There is an argument that suggests that designing a bespoke system
ROBOT CONTROL... Making the right choice
cost. The robot mechanical system is already designed and its CAD model can be imported into the machine design, saving time and cost. When the system is being built the robot is also simple to install, needing just four bolts to mount it into a machine, and it can be programmed in less than an hour to do a simple operation. The controllers contain hundreds of dedicated instructions that
make the more complex functions – such as tracking a product along a moving conveyor or complying with an external force – easy to integrate as they are already built into the system. Of further benefit, robot controllers have to conform to
By following a few best practices and principles, it is possible to select a control option that meets the requirements of the application whilst maximising productivity and ROI
industry standards that cover their design, which includes safety. This means that it is much easier for the system designer to achieve an integrated safety system for the total machine by using compliant components.
may offer a price advantage as it is often less expensive to buy a kit of parts and build the system from scratch than invest in a traditional robot arm. Indeed, this may suit an OEM with multiple systems to build. While the application will determine the best approach, designing in this way can allow an OEM to create a tailor made solution. An example would be the control of a bakery tin store. The motion
profile of this application is a very simple pick and place operation with maybe two or three axes of control. However, the mechanics can be very large, having to span tens of metres of the store. Using the built-in kinematics of the iQ-R PLC system, the set-up times and programming of the control system can be reduced, as the tin positions can be taught or the co-ordinates calculated in the control system. This system also allows other axes to be easily integrated into the system. It could, for example, be expanded to include the control of the delivery system, bringing the tins into, or away from, the store.
DEDICATED ROBOT CONTROLLERS Choosing a PLC-based robot control option may seem like the most cost-effective option. Yet, it is important to consider the design time of the mechanical system, the flexibility required from the manufacturing cell, the cell footprint, and also the configuration and engineering time. This is taken care of by selecting an off-the-shelf dedicated robotic system. A typical 4-axis SCARA (Selective Compliance Articulated Robot Arm) system, for instance, can now be supplied at a very competitive
30 SEPTEMBER 2019 | DESIGN SOLUTIONS
SELECTING THE MOST SUITABLE SOLUTION If the choice between dedicated or PLC-based robot control is still in the balance, then manufacturers that provide both, such as Mitsubishi Electric, can support machine builders and robot integrators alike in selecting the most suitable alternative. Customers can choose between state-of-the-art PLCs and dedicated robot controllers to match the requirements of their systems. The company offers advanced MELFA robot controllers which allow
users to programme the robots by using the powerful Mitsubishi Electric RT-Toolbox engineering environment. When PLC-based control is preferred, Mitsubishi Electric’s iQ Monozukuri Handling Suite empowers users to take control of movement and information management tasks. This features a handling application package and a control program that connects the MELSEC iQ-R PLC series of high-performance and scalable controllers with robots, HMIs and other compatible automation components. In addition, when the best of both systems is needed, Mitsubishi Electric
offers the option of integrating a dedicated robot controller directly into the PLC rack. The controller is compatible with the company’s iQ modular PLC platform, which can seamlessly integrate a range of different functional controllers along with I/O and networking options. In the end, the control requirements and the physical attributes of the
application often dictate which option is best. But, for machine builders and integrators alike, it would be sensible to adopt a flexible, integrated automation solution that offers choice and scalability.
Mitsubishi Electric
gb3a.mitsubishielectric.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
