Interactive robotics – the key to small series production?

Over the past couple of years, robotics has frequently made the headlines.  For example, Frost & Sullivan have listed robotics as one of the future megatrends. It is expected to gain a similar position as the Internet. The expectations of robotics are high, particularly in terms of its ability to increase efficiency in European and Finnish manufacturing.

Robotics to promote European manufacturing

Attitudes to robotics in production are contradictory: on the one hand, manufacturing is expected to get a boost in efficiency, but on the other hand, there are fears that jobs will be lost. However, more efficient production can mean the preservation of current jobs, the creation of new ones and a change in the nature of work in a more technical direction. Robotics can thus help European manufacturing to survive in the face of the competition from lower-cost countries.

Industrial robots and humans

In industrial robotics, cooperation between humans and robots is a new phenomenon that is referred to using terms such as interactive robotics, collaborative robotics or human–robot interaction. They all mean that a human and robot work simultaneously within the same space. The human can even be in physical contact with the robot. Interaction makes it possible to effectively utilise human perception abilities and powers of reasoning.

New standards as an enabler

The introduction of interactive robotics in industry has now been made possible by new safety standards for robots, ISO/TS 15066 in particular. It identifies four types of collaborative operations: safety-rated monitored stop, hand guiding, speed and separation monitoring, and power and force limiting. Within these categories, robots no longer need to be isolated from their operating environment in e.g. cages.  When a robot is performing an automatic task, a human approaching or even entering its workspace does not have to trigger an emergency stop – reducing speed and, if necessary, stopping movement is enough. When the human has left the space, the robot can continue operating as usual. Moreover, if the force exerted by the robot is sufficiently small and the robot reacts to contact, it can operate alongside humans. Possible dangerous situations caused by the robot tool must naturally be taken into account.

From a future concept to agile small series production

It took quite a while before technology – and standards in particular – developed to the level required by practical applications. Professor Aarne Halme, who at the time worked for the University of Oulu and later became a long-time Professor of Automation Technology at the Helsinki University of Technology and a prominent figure in the field of robotics in Finland, introduced interactive robotics as early as the beginning of the 1980s. I myself used the heading of this article as the title of my conference presentation in 1987. Today, interactive robotics accelerates production and increases efficiency. It makes the programming of tasks faster and enables the automatic or semi-automatic execution of production tasks.  These issues are of key importance in agile small series production, in which new goods are continuously put into production and batches of a few items or even single items are common.

Inexpensive force-limited robots

Several force-limited robot models – lightweight desktop robots – have been brought to the market whose accuracy is measured in hundreds of a millimetre at best. These robots can cost less than €20,000, meaning that investing in a robot now involves much less costs than before. Thanks to power and force limiting, cages are not needed to ensure safety. However, force-limited robots run at significantly lower speeds than regular industrial robots. Additionally, due to the less expensive materials and components used, their effective working hours can fall short of those of regular robots.

VTT's control stick enables faster teaching of paths

VTT’s control handle enables faster teaching of paths

Teaching a robot

In interactive robotics, a human interprets the environment for a robot and its sensors by pointing with a device or by using simple marking methods such as identifiers. The human tells the robot what the environment contains and, for example, which surface of a workpiece must be polished. The robot’s paths can also be programmed by showing the robot where to pick up and drop off a piece, or by teaching, for example, polishing paths with a tool attached to the robot and in contact with the workpiece. This can also be done without saving the robot’s path points, in which case the robot can be used as a skilful assisting device for moving heavy items. Heavy objects can even be assembled using this method. The human operator grabs the robot’s wrist or a control handle attached to the load and guides the robot to pick up the object and drop it off at the destination. In the interactive handling of objects or teaching of paths, it is essential that the robot is equipped with a sensor that recognises forces and with corresponding force/torque control.

VTT is a pioneer in interactive robotics

Technologies related to interactive robotics feature strongly on VTT’s robotics agenda. We have developed methods and wireless technologies for the observation and recognition of objects and humans, and have integrated these into the controls of robots and robot systems in order to provide flexibility and safety. Interactive robotics is a promising starting point for the needs of automation in small series production. VTT is ready to tackle challenges put forward by companies.

Tapio

Tapio Heikkilä

Principal Scientist

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