In Human Robot Collaboration, a collaborative robot, Cobot for short, encounters its human colleague without barriers. To do this, the robot has to meet various requirements. Read here which ones and much more.
Robot Human Collaboration (HRC) refers to all processes in which humans and machines work and interact with each other in the same work flow, without any barriers between the individual work areas. People and HRC robots therefore share a single workspace, which does not require separating protective equipment. A more precise and technically optimized definition is given by DIN EN ISO 10218-1, which specifies international standards for the use of industrial robots.
Use of collaborative robots in production
First, the advantages of human-robot interaction must be examined in detail. Companies can benefit from the use of collaborative robots in manufacturing:
- Maximum flexibility in a wide variety of production areas
- Professional execution of processes that can be reproduced at any time without the need for component-relevant investments
- Intelligent sensor technology can improve plant complexity over the long term
- Higher productivity due to reduced downtime and higher load capacity of the collaborative robot
- Reduction of potential hazards by avoiding injuries, e.g. by using appropriate grippers
- Reduction of strain on employees in production: Process steps that were previously impossible to automate can now be handled by grippers and HRC robots.
In order for companies to benefit from the advantages of human-robot collaboration, a number of requirements must be met. But, a collaborative robot alone or the use of grippers is only half the rent.
Important prerequisites for human robot collaboration
In order for a collaborative robot to be used in a productive environment, different prerequisites and standards must be fulfilled. After all, a collaborative robot must work directly with people across a wide range of production areas and must not harm them in any way. On the one hand, this means that there must be suitable and sufficiently dimensioned safety systems for human robot interaction. Furthermore, the type of production must be suitable for the use of a human robot collaboration in the first place. This can be the case, for example, when parts of human production can only be carried out with difficulty or in non-ergonomic positions. Such a case can either be handled by a collaborative robot equipped with a gripper, or it can support the human operator in these steps.
Where do HRC robots pay off?
There are hardly any restrictions or limitations on the use of human robot collaboration in different industries. After all, an HRC robot can be designed and deployed in different sizes and with different functions. Starting with small grippers for production in the fine parts segment through to semi-automatic production in vehicle construction or industrial manufacturing, many systems are feasible and already exist in some parts.
The more important question for many companies is how profitable the use of a human robot collaboration actually is. This is usually a question of economic calculations. Human-robot collaboration can, for example, replace employees in different manufacturing processes or simplify production steps and thus save direct costs. By assuming undesirable tasks that can only be performed by people under physical strain, a collaborative robot also saves secondary costs caused by sick leave and corresponding production downtimes or overtime. In addition, a comprehensive and complex human-robot collaboration system can also streamline the entire production process, resulting in higher output, better workflow, and higher production output. The better the human-robot interaction can be integrated into a production process, the more economically this process can be used.
Implementation of HRC in the actual production process
Various collaborative robots and grippers are already in use in certain applications. The first HRC robot that has been approved worldwide is the lightweight robot LBR iiwa from Kuka. Thanks to the integrated sensor technology, the gripper can be easily trained for human-robot interaction and thus integrated into a wide variety of processes. This HRC robot, for example, detects the correct and required installation position and can therefore assemble individual parts quickly and with maximum precision. In the area of human-robot collaboration, the LBR iiwa assumes those tasks that would burden the employees because of unergonomic and monotonous tasks. As a collaborative robot, the LBR iiwa reacts to the human being in its surroundings and can be adapted to its field of work by this person without any further knowledge. Various safety systems ensure that a collaborative robot does not pose a danger to employees. The HRC robot thus serves as the third hand of the employees in small-scale production processes and supports the human being as required.
A look into the future of human robot interaction
The current systems, however, are only a first step in the field of human-robot interaction. Thanks to further research in artificial intelligence (AI), the programming of HRC robots will probably become much easier or even unnecessary in the future. Self-teaching programs can certainly make it possible for human robot collaboration to reach a whole new level and for the various grippers and HRC robots, for example, to independently improve production processes and thus ensure even higher productivity. In addition, the robot systems themselves will also become better and more flexible. The use of modern materials and the associated reduction in wear will also significantly reduce maintenance efforts and costs in the long term.
There are still significant developments to be expected in the field of human-robot collaboration, which can hardly be anticipated from today's perspective. Basically, experts assume that human-robot collaboration will only last to a certain extent before human beings no longer need to be involved in the active production process. In this scenario, production will be handled exclusively by robots, while humans will only be responsible for the control of the processes. A collaborative robot might still be a real asset in this day and age, but in fifty years' time the world of manufacturing will have changed significantly.
Safety systems and safety concepts for HRC robots
In human-robot collaboration, elaborated safety systems have an important role to play. After all, a collaborative robot will be operating in direct human-robot interaction without any protective partitions or grids and is often far superior to humans in terms of weight and strength. In human-robot collaboration, humans must therefore be protected by existing and elaborate safety systems at every step of the work process. In total, there are four different approaches that can be applied to human-robot interaction.
1. Power and force limitation of HRC robots
- With this system, a mechanical, electronic or even sensory restriction of the force is used in the HRC robot to make human robot collaboration safer. It is based on the so-called force atlas consisting of ISO/TS15066 and ISO 10218-2. It comprises so-called biomechanical limit values, which must not be exceeded by robots in direct contact with humans.
- These safety systems can be applied to any human robot interaction and offer a high level of safety. For example, a gripper cannot exert more force than a human can withstand when their hand is caught by the gripper. In this respect, a collaborative robot must operate with a clearly limited force.
2. Continuous control of speed and distance
- For this form of human-robot collaboration, a person recognition system must be installed at the HRC robot. The working speed of the robot must be reduced as soon as a person approaches the robot. If the person enters a certain boundary area, the safety systems activate. In this case, a collaborative robot must stop immediately and safely to allow clear control. The human can therefore not get injured because the robot stops all work within a danger radius.
3. Immediate and controlled stop at human interaction
- This safety system for human-robot interaction is a variant of continuous control. This variant is mainly used when human and HRC robots share a workspace, for example in consecutive production, but do not use this space simultaneously. If a person enters the workspace, the safety systems immediately engage and the HRC robot reliably interrupts its work. In this way, human injury caused by the movement of the robots can be avoided.
4. Manual control of the robot
- A collaborative robot can be guided manually by a joystick or by a force-moment sensor. In this case, the HRC robot can be guided by simple human contact during human-robot interaction. An important aspect of these safety systems is the clear limitation of the robot's force and speed. In addition, an emergency stop device must always be available in the vicinity of the operator.
- This makes human-robot collaboration much easier, especially for smaller and delicate productions. The larger the robot in human-robot collaboration, the more difficult it is to effectively implement these safety systems.
The limits at the fringes of human robot collaboration
It is not easy to explore human robot collaboration further, as there are many boundaries that must not be crossed in this form of development. Human-robot collaboration can only take place within certain boundaries and standards, which are defined by the appropriate professionals in the different disciplines. Since in human robot collaboration the human being is usually always the weaker and limiting factor, the above mentioned values for pressure or pain must be considered in all developments. Although this slows down the development of human-robot collaboration, it also ensures a very high safety standard during development and thus a higher acceptance among employees.
This takes us to a difficult topic. If you want to introduce human robot collaboration in your company, for example through the use of grippers, this can only be done with the support of your employees. For many employees in production, a collaborating robot is first and foremost a competitor with a significantly higher level of performance. A collaborating robot is therefore not seen as a good thing by most employees. HRC robots and grippers should above all be considered as a means to facilitate work. The more unpleasant and uncomfortable tasks are performed by the HRC robot or the gripper, the easier it is for employees to understand the benefits of human-robot collaboration. Comprehensive information of the employees is necessary for human robot interaction to be implemented successfully.
The efficiency increases expected from human-robot collaboration
Overall, a sound and, above all, well implemented human-robot collaboration can change and restructure the entire production process in a company. A collaborating robot in different application areas can speed up parts of the production and thus enable new processes. For this reason, human-robot collaboration should only be introduced if companies are aware of the effects it will have on the entire production cycle. A collaborative robot can influence many processes in a sustainable way and above all in the long term. If it is possible to implement such a system, experts expect an increase in efficiency of at least 30 to 40 %. This increase will be achieved on the one hand through higher productivity, but also through the reduction of workforce and sick leave. However, it is not possible to quantify the exact amount of the increase in efficiency achieved by human-robot collaboration, as this can vary significantly from company to company and industry to industry.
The way ahead to industry 4.0 and the use of automation and robotics in production
By developing ever better sensors and ever better HRC robots, human-robot collaboration will improve significantly over the next few years and be applied in more and more companies. Sooner or later, however, humans will be pushed out of most production processes because grippers and robots will be able to do most of the work faster, more efficiently, and in a shorter time. It will take time for human-robot collaboration to lead to complete automation, but the trend itself is indispensable and irrefutable. Human-robot collaboration marks the beginning of a new era of production that will fundamentally change many companies.