Cobots: towards safe human-robot collaboration
Since the 1970s, industrial robots have reshaped manufacturing, increasing automation by taking on high speed, high output repetitive tasks with very low error rates, often performing tasks that are dangerous, undesirable or unsuitable for humans. Applications include arc welding, painting, material handling and mechanical assembly.
Traditionally, these industrial robots - such as the robotic arms found on many automotive production lines - are bolted to the floor and encased in protective cages or otherwise physically separated on production lines isolated from people because their construction, heavy bulk and powerful, rapid movements making them unsafe for close human interaction. They also typically require very specialised programming and are consequently rarely reprogrammed or moved to address other tasks once installed.
As well as their relative inflexibility, cost has been a barrier to widespread adoption of industrial robots; both high initial purchase costs and the costs associated with programming, tooling and deploying the robot. While they often make sense for high volume, high value manufacturing production, small and medium-sized manufacturers with smaller volumes and higher mix have sometimes struggled to justify the expense. The move away from the mass production ethos to a more flexible and adaptive response to customer demands, together with a number of innovations in sensing and vision technologies, is now driving a reassessment of the relationship between man and machine to one which is based on collaboration, rather than segregation.
Modern manufacturing typically employs automation technology to carry out everyday tasks in factories such as gripping, moving and positioning goods and materials. Increasingly, these movements require precision with very small margins for error and a delicacy of touch that traditional industrial robots were never designed to deliver.
Nature performs these tasks instinctively and efficiently, applying just the right amount of force and speed to achieve complex tasks. So, what could be more logical than to examine these natural phenomena and learn from them? Festo’s Bionic Learning Network (BLN) is a research, development and innovation alliance that draws inspiration from nature to develop innovative biomimetic technology concepts that also have the potential to enhance industrial automation applications. Founded in 2006, it links the company’s design engineers to renowned universities and institutes, as well as external R&D partners, in a dynamic and open exchange of ideas.
Previous BLN Future Concepts have demonstrated intelligent subsystems and components drawing on natural examples. Previous iterations have included bionic ants, dragonflies, jellyfish and penguins and featured such innovations as the eMotionButterflies that use intelligent indoor GPS with infrared technology to move in an enclosed space without colliding; the BionicKangaroo that recovers kinetic energy on landing, storing it and efficiently using it for the next jump; and Air_Ray, which uses lightweight design and lift from helium to “swim” in a sea of air like a manta ray in water.
This year’s innovations, demonstrated for the first time at Hannnover Messe, focus on robotic concepts which are ideally suited for safe human-robot collaboration, due to natural movement patterns and inherently compliant pneumatics. The evolution of these lightweight collaborative robots, or ‘cobots’ offers a new, safer and more cost-efficient alternative for closer proximity working with humans. The BionicCobot is inspired by the natural movement of the human arm; the BionicMotionRobot mimics the way elephant trunks or octopus tentacles move; and the OctopusGripper is modelled on the way they grip.
The BionicCobot uses precision-controlled closed loop pneumatics in each of its seven joints to emulate the natural movement of the human arm it is modelled on. Its movements can be finely regulated from powerful and dynamic to delicate and yielding using Festo’s Motion Terminal, a new digital pneumatics platform combining high-precision mechanics, sensors and complex control. This allows the whole system to rapidly adjust to different dynamic requirements with extreme precision and reliability. Workers are protected as the system can simply ease off in the event of a collision. Operators can “teach” the BionicCobot actions via an intuitive graphical simulation interface which enables required movements to be parameterised as steps, which can then be sequenced as required.
The BionicMotionRobot features 12 degrees of freedom, emulating the fluent movements of an elephant’s trunk or an octopus’s tentacles, by using multiple segments, sturdy elastomer pneumatic bellows and inherently flexible kinematics. A 3D textile knitted fabric provides an outer skin that enables the force potential of the entire kinematic system to be fully deployed, with a payload of almost three kilograms. The textile replaces the rigid metal casings of traditional robots with something more tactile and soft, making contact with humans more forgiving.
The OctopusGripper consists of a pneumatically-controlled soft silicone structure which can bend inwards and wrap around the object to be gripped in a form-fitting and gentle manner. Two rows of actively and passively controlled suction cups increase its ability to pick up and hold a wide range of different objects. Paired with either the BionicMotionRobot or the BionicCobot, it can address a wide range of potential gripping applications and also fulfils the strict criteria for a soft robotics component.
Collaborative working spaces of the future
Advances in computing power and sensor and vision technologies are helping to drive the development of a new generation of more adaptable, lower-cost, lightweight and mobile robots, capable of collaborating more safely with workers on the shop floor. This makes them more compelling for small and medium enterprises, with a lower price entry point, and the flexibility to easily move and reconfigure the robot to address different tasks. Able to work safely alongside human co-workers, they can assist them in shared work processes. They use sensors to detect abnormal or unexpected activity in their environment and force limitation to eliminate or minimise contact. And they can typically be easily programmed without coding via graphical interfaces on a tablet or by simply moving them in the required pattern.
Increasingly in the factories of the future, strict separation between factory workers and industrial robots will give way to collaborative working spaces. In the production of tomorrow, humans and machines will be able to safely work together on the same work task or process, and this direct interaction between man and machine will be part of the daily routine. Festo’s lightweight bionic robotic concepts, utilising natural movement and the inherent flexibility of pneumatics, are destined for collaborative working spaces and help point the way to this smarter future.
Steve Sands, Head of Product Management, Festo