Electroadhesion, also known as electrostatic adhesion, is an electrically regulated mechanism, that creates attraction between two materials. Utilized in robotic handling, climbing, and active adhesion[1].
This term was coined by Danish scientists Johnsen and Rahbek in 1923, while working with polished lithographic stone and metal surfaces to describe the physical phenomenon of significant adhesion that occurred when the highly resistive stone was placed on top of a metal plate and a high voltage was applied between them[2]. When a conductor and a semiconductor are in contact and a voltage is applied across the two materials, the conventional Johnsen–Rahbek (J-R) effect explains the attractive force experienced between the two materials.
To date, a wide variety of other standard adhesion techniques have been used to stick objects or materials together temporarily. Chemical adhesion, synthetic gecko feet, suction cups, mechanical and magnetic gripper are some of these techniques. However, they are still not enough to cover all the challenges.
Electroadhesion mainly takes its place where the standard solution creates damage and marks on the product or fails to stick it effectively and efficiently during the process.
Although this technology has improved over the years, two major problems remain. It is extremely difficult to adjust and eliminate the attractive force created, in a fast and controlled way. These points assume special importance when applied in industrial applications.
PoleAttraction™, an Engimotion development and the ultimate evolution of electroadhesion, intends to solve these challenges. Especially focused on non-conductive materials, it promises a fast and controlled delivery of the handled part at the delivery point, as well as handling of product stacks, with the defined number of layers, reliably.
Figure 1: Before PoleAttractionTM (left). After PoleAttractionTM (right). How does PoleAttraction™ Work?
PoleAttraction™ consists of an advanced electronic controller and a set of attraction pads. The controller is responsible for energizing each pad, generating a magnetic field that will polarize it and the non-conductive part or surface in contact, creating an attractive force between them[3], according the defined thresholds and orders received through the existent interfaces.
The pad is based on a capacitor model, where the part to be handled is included, and normally depending on the application, it can have various sizes, shapes, and levels of rigidity[4]. PoleAttraction™ uses a proprietary design that ensures effective attraction with over 90% non-conductive materials and surfaces.
Each PoleAttraction™ pad needs a specific combination of certified materials, applied through a very demanding and controlled manufacturing process, to ensure, beyond the good functioning, a fast and controlled attraction response.
Figure 2: Cross section of the PoleAttractionTM pad. Image credit: Engimotion.
Nonetheless, to achieve really interesting and viable performance results, the PoleAttraction™ controller was developed with an integrated closed loop control, empowered by artificial intelligence, which manages the amount of attraction with the part or surface in real-time.
PoleAttraction™ has a number of advantages over other standard adhesion techniques, such as pneumatic, mechanical, magnetic, and bioinspired, even if combined.
The following are some of the main advantages that make PoleAttraction™ so interesting for certain areas, products, and applications:
The PoleAttractionTM Pad. Image credit: Engimotion.
Applications of PoleAttraction™ in the Real World
PoleAttraction™ can help in a wide range of applications, in different areas and equipment. As a disruptive solution that offers new capabilities, the most demanding situations are those where standards adhesion solutions fail to effectivity and efficiently solve the challenge. However, the recent focus on electrical efficiency opened the door to a wide range of applications, where standard adhesion solutions has been applied.
In the next points we will present some particularly advantageous applications of PoleAttraction™ technology:
Several major applications have been presented since the inception of electroadhesion, enabling technical improvements ranging from robotic gripping and climbing to active adhesion and biomedical applications. It has been determined that an increase in electroadhesion research is both foreseeable and necessary. To that purpose, this article provides a presentation and overview of the new and disruptive PoleAttraction™ approach, including how it works, its benefits, and its applications.
With these in place, the industrial community has at its disposal a new technology capable of being applied in more sectors and applications, improving the efficiency of its processes. Some existing limitations are now solved with PoleAttraction™, increasing the quality of products, processes, and working conditions.
While it is unclear how near scientists and companies are to developing one efficient electroadhesive technology, one thing is certain: Engimotion’s PoleAttraction™ has arrived.
Engimotion is a Portuguese start-up based in Porto with an aim of making the cutting-edge world of robotics accessible to SME’s.
References
Embedded & Autonomous Robotic Systems Engineer.