What's so Special About a Parallel Robot Gripper?
Posted on Jun 26, 2018 7:00 AM. 5 min read time
What's the benefit of a new type of robot gripper? The newest addition to the Robotiq family — the Hand-E Adaptive Gripper — answers this age-old question.
We have just released our Hand-E Adaptive Gripper. It's a translational, parallel gripper. You might be wondering what makes it so special compared to our existing range of Adaptive Grippers, which are rotational, parallel grippers.
You might also be wondering: Why should I use a translational gripper when the rotational grippers are so popular?
In this post, we tell the story of how these two types of gripper came into being and we address the question "Do I need a translational or a rotational gripper?"
Hand-E is the first UR+ gripper ready for the new Universal Robot e-Series
In the beginning: there was a problem with pneumatic parallel grippers
The question of "Which parallel gripper is best?" is a long-standing one. It stretches all the way back into the last decade.
The story starts with a related question: "Which is better: pneumatic grippers or electric grippers?"
You see, Hand-E is certainly not the first translational, parallel robot gripper on the market. In fact, the first ever industrial robot, the Unimate, had a rigid parallel gripper. For years, the vast majority of grippers were pneumatic — 80% in 2011, according to an article which was written in that year. While there were some advantages to pneumatic actuation (e.g. faster actuation times and lower cost), these grippers were not very flexible.
Traditional pneumatic parallel grippers had several problems:
- They were usually supplied with no fingertips — only an actuation block — so you had to make your own custom fingertips for every task.
- They lacked precise control, being either fully open or fully closed.
- They required compressed air which was a pain if you didn't have pneumatics already installed.
- They had no built-in grip detection.
An alternative is born: Robotiq's adaptive grippers
When Robotiq started making grippers a decade ago, our CEO, Samuel Bouchard, wanted to overcome the limitations of pneumatic grippers. In previous articles, he has explained the advantages of electric grippers and the problems with pneumatic grippers. He and co-founder John-Philip Jobin focused on making adaptive electric grippers which were inherently flexible and could be used out-of-the-box.
Since then, we have become renowned for our 2-Finger and 3-Finger Adaptive Grippers. Some of the unique properties of these grippers are:
- Wide stroke, which can just as easily pick up both large and small objects.
- No need for customized fingertips (unless you want them). You can attach the gripper in minutes and start using it immediately.
- Their patented mechanical linkage design means they can grip unknown items securely. See Mathieu's article for details about how the grippers work.
- Parallel grip and encompassing grip. This linkage design also means they can grasp objects with two grips: a parallel grip and an encompassing grip.
- Integrated part detection, position feedback and part validation.
Our existing grippers are also parallel grippers. Their fingers are constructed using parallel linkages which allow the fingertips to follow an almost-linear motion. However, the motion of the fingers follows a slight curve, which can make it challenging to use them for high-precision tasks.
Our electric grippers showed that you didn't need pneumatics to have a high performance, lightweight, reliable gripper at a reasonable cost. They also showed that adaptivity is very important, especially in high-mix environments where various objects need to be manipulated by the robot.
The world changes… and a new need appears
When Robotiq began, we were up against the received wisdom that pneumatic grippers were better than electric… boy, did we show that to be wrong!
The world has changed a lot since the early days of Robotiq. These days, electric grippers are quickly becoming the norm in some parts of industry.
Back in 2013, experts stated "The reasons why pneumatic grippers dominate electrical grippers are obvious" claiming they were more reliable, faster and offered more size options. Now, in 2018, those reasons are no longer so obvious, with experts explaining "Electrical grippers have clear advantages over pneumatic grippers…since electrical drives and motors are becoming smaller, lighter, and more powerful."
How things have changed in just 5 years!
Our grippers demonstrated the advantages of electric grippers and the industry finally agrees with us.
We probably could have kept making only rotational grippers. But, recently people started coming to us with a new need. They were missing some of the customization and high precision that those traditional translational, parallel grippers provided.
The new generation of electric translational gripper
We wondered: Could we combine the benefits of our electric rotational grippers into a translational, high-precision gripper?
And that was the birth of Hand-E.
Hand-E is a translational, parallel gripper. But, it is quite different from those early pneumatic grippers with all their limitations. It combines the advantages of today's electric gripping technology with the customization options of a translational gripper.
In its own way, Hand-E is also very adaptive. That's why it's part of the Adaptive Gripper range. Instead of adapting to objects by its flexible finger structure — as the 2-Fingered Adaptive Grippers do — it allows you to adapt the fingertip design (if you want to) to suit your application.
Here are some of the unique properties of Hand-E:
- Sub-mm precision.
- Built-in grip detection.
- Wide stroke, for its size.
- Able to work in tight environments.
Our 10 years experience making grippers has given us the expertise we needed. We've now created a plug-and-play gripper which has both the advantages of our rotational grippers and the advantages of translational grippers. But, without the disadvantages of those pneumatic actuators.
Do I need a rotational or an translational gripper?
You might be thinking: The new gripper sounds good, but how do I decide between an rotational and a translational gripper!?
The decision of which type of gripper you should purchase is often a hard one. There are so many options on the market! In the past, you may have seen catalogs with pages and page of actuators, including hundreds of models of similar-looking grippers.
Don't worry. At Robotiq, we like to make decisions as simple as possible.
Get in touch and we'll help you to decide which type of gripper is best suited to your application.