Grasping Static Electricity for Revolutionary Robotics

Levitating one’s hair to demonstrate static electricity by using a charged balloon is a classic science experiment. But, imagine if the same static cling could be harnessed to handle a material as flimsy as soft fabric, as fragile as an egg — or to assemble the uppers of Nike trainers at 20 times the pace of a human worker. Envisioned in the heart of Silicon Valley, in Sunnyvale, California, robotics start-up Grabit is harnessing static electricity, machine learning and automation from Toshiba Machine partner, TM Robotics, to accomplish just that.

Material handling is one of the most labor-intensive and costly aspects of manufacturing, and when dealing with a range of different materials, the process is difficult to automate. Putting together a pair of Nikes requires nearly 40 pieces of material to be stacked and heated to create the upper — the flexible part that sits on top of the foot. For a human worker, assembling the pieces of material can take up to 20 minutes. However, Grabit’s technology allows a machine to achieve this in as little as 50 seconds.

Despite its evocative name, Grabit’s material handling invention does not imitate the human grabbing motion that can be found in many robots. Instead, the start-up harnesses static electricity — called electroroadhesion — to handle materials in a way no robot has before.

Electroroadhesion

The electroroadhesion concept was discovered at non-profit organization, SRI International, by Grabit’s co-founder and chief technology and products officer, Dr. Harsha Prahlad. The process uses a flat pad of electrodes to produce positive and negative charges on the surface. When charged properly, the electrodes produce an electric field that adheres to virtually any surface, allowing the robot gripper to pick up the part that is being handled.

Prahlad and company currently hold 36 separate patents associated with electroadhesion and the total number of patents issued, pending, granted and applied for is 75. However, upon identifying that materials handling was accountable for 60 to 80% of labor in manufacturing, he decided that it should be the first application in which he applied the technology. Following Grabit’s launch in 2013, Nike Inc. made an investment in the company and later became one of the first customers to purchase its materials handling robot system, Stackit. Using Stackit, Nike can make 600 pairs of shoes within one eight-hour shift.

The new system would eventually be able to assemble precise layers, such as those found in the Nike shoe upper, twenty times quicker than a human being. Its return on investment period would be only two years.

Stackit

The formation of Stackit commenced in summer 2015, but before the manufacturing process could start, the company had to decide on the right robot to mount the ground-breaking electroadhesive gripper on. Having witnessed a Toshiba Machine robot arm used to mount one of its grippers by a customer — a Japanese circuit board manufacturer — Grabit was fascinated to see how the robot manufacturer’s machines could be used as a larger part of Stackit’s development.

Choosing the wrong robot could have a detrimental effect on the entire design of the system. Two members of our team already had extensive experience in robot design, and both had been involved in the development of several SCARA robots. This prior understanding of industrial robots enabled us to fine tune our requirements before approaching any manufacturers.

Greg Miller, President and CEO, Grabit

After choosing a few promising robot manufacturers, Grabit planned a wide-ranging test and selection procedure to test the potential of each one. “The process looked at several factors,” explained Prahlad. “Because of the vast applications for Stackit, we needed a robot with a large reach, that would not lose the high levels of precision needed for exacting material handling applications like the shoes from Nike. What’s more, because Grabit’s electroadhesion gripper is so large, the robot needed to be able to withstand a big moment of inertia and offer the ability to rotate accurately.”

Despite preliminary excitement, the off-the-shelf Toshiba Machine robot that the company tried, did not meet Grabit’s demands.

Meeting Stackit’s ‘twenty times faster’ productivity goals rely heavily on the inertia of the gripper and ensuring that the settling time of the robot remained accurate. But the robot also needs to move fast enough to provide customers with the cycle times we wanted. It became plainly obvious that there was no standard robot that could meet every one of our requirements.

Dr. Harsha Prahlad, Co-founder and Chief Technology and Products Officer, Grabit

Locating a customizable robot at a competitive price point was difficult, but manufacturing in the footwear and apparel sectors is driven by costs. Integrated with the additional financial pressure of low labor rates in many manufacturing countries, Grabit required a cost-effective robot. This was the moment when TM Robotics, Toshiba Machine’s American and European distributor, truly proved its worth on the project.

“As a start-up, we needed a robot provider that could support us through the entire process, not simply sell us the product and leave,” explained Miller. “Despite being an official partner for Toshiba Machine, TM Robotics could also provide the careful and attentive sales, service and support of a much smaller company.”

Grabit’s demands were unusual. In contrast to many robotics applications, there was no need for several complex motions and the company did not require the array of movement provided by a standard, six-axis robot. However, as Grabit wanted to employ its own control system to supervise the whole machine, they needed deep access to low level internal control code and the control package had to be sufficiently small to fit into a tight space in the design.

Following some modifications to the off-the-shelf Toshiba Machine robot, the equipment was still not stabilizing quickly enough. As a result of the inertia of the gripper, followed by the time taken for the gripper to rotate and the robot to settle and stabilize, it was unable to hit the cycle times the company had aimed. In fact, to hit the cycle times Grabit wanted, a special transmission was developed for the system.

To help realize this, TM Robotics flew Toshiba Machine’s chief engineer from its headquarters in Japan to Grabit’s base in California.

“TM Robotics’ support and customization process was not limited to phone calls and e-mails,” explained Prahlad. “Working in collaboration with Grabit’s knowledgeable robot engineers, they were able to talk to us in a language our technical team understands and allowed us to fine tune the machine to our exact requirements — not many robot companies allow for that level of personalization.”

“We worked alongside the TM Robotics team until we got to a point where the robot was ready to be used in a manufacturing facility.”

Toshiba Machine’s THL1000 SCARA Robot

Grabit used Toshiba Machine’s THL1000 SCARA robot in the Stackit application, a horizontal multi-joint machine with four controlled axes. Having a 1000 mm arm length, the THL1000 has the largest reach of the THL robot range. The allowable moment of inertia is only 0.2 kg/m2 and, because of using absolute encoders, the robots’ repeatability in X-Y is 0.01 mm.

As standard, the robot offers the highest payload of 10 kg against a total mass of 37 kg. With a tested load of 2 kg, the machine can accomplish a cycle time of just 0.48 seconds. However, because of the specific load requirements for Stackit, Grabit’s tailored version was created using a different ratio of gears, causing an improvement in payload capability. This enhancement, integrated with the repeatability of the machine ensured it was able to deliver the necessities for Grabit’s gripper.

Automation trade shows and magazines are full of humanoid robots with hand-like grippers, built to automate jobs that humans have been performing for years. However, until the launch of electroadhesion, manufacturers have been incapable of automating the task of fine materials handling. Grabit’s electroadhesive gripper introduces this technology to the industry, stacking materials like meshes, leathers, and composite fibers without a snag.

Grabit’s electroadhesion technology was not only impressive, but innovative enough that we were keen to get involved. Grabit’s experts knew exactly what they needed, and our close collaboration led to an insightful process of experimenting and fine tuning the capabilities of our existing Toshiba Machine robots.

Nigel Smith, CEO, TM Robotics

Conclusion

The number of industrial robots used globally is predicted to increase to about 2.6 million by 2019. That’s about one million more robots than 2015, which was a record breaking year for robotics. Grabit’s deployment of electroadhesion boosts the time-saving and resource-saving potential of these units and its unparalleled flexibility opens doors to completely new possibilities in automation — remarkable stuff for the same force that lifts strands of your hair using a balloon.

TM Robotics

This information has been sourced, reviewed and adapted from materials provided by TM Robotics (Europe) Ltd.

For more information on this source, please visit TM Robotics (Europe) Ltd.

Image credit: TM Robotics

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