In robotics, the robot "hand" is the ultimate touchpoint for every product or part that goes out the door. Smart factories can only achieve the agile, super-connected and collaborative environments envisioned by Industry 4.0 if all of the systems are intelligent, and add value to the overall enterprise. Robot grippers need to be smarter than average. Here are some new grasping systems that have moved to the front of the class.
One of the ways robot grippers are getting smarter is by learning to play nice with humans. Automation has become less about replacing humans. Now, it's more about humans sharing production responsibilities with their robot coworkers. Collaborative robots, or cobots, are at the center of the movement. This is focusing more attention on collaborative gripping solutions.
Gripper designed specifically for human-robot collaborative applications has limited force and no sharp edges or pinch points for safer operator interaction.
Co-act, which stands for collaborative actuator, is a family of collaborative grippers made by SCHUNK. The series is based on the company's tried-and-true gripping technology with modifications to limit force and prevent other potential hazards when working closely with people. The company took its standard, electric 2-finger parallel gripper and built a protective housing around it with rounded corners to eliminate sharp edges and pinch points.
The Co-act EGP gripper is force limited to comply with technical specifications that provide thresholds for maximum permissible pressure and force.
"The biggest difference between a standard EGP gripper and the EGP we use on the collaborative robot is that we safely limited the force to 140 newtons," says Markus Walderich, Automation Group Manager at SCHUNK Inc. in Morrisville, North Carolina. "We also made sure that if something should go wrong with the power supply, there's no way the peak force could ever surpass 140 newtons."
The Co-act gripper series is compatible with a variety of cobots on the market. These include the KUKA LBR iiwa (pictured), FANUC compact CR-4iA and CR-7iA, Rethink Robotics Sawyer, Techman TM5, Universal Robots UR series, and the Yaskawa HC10. The Co-act MPG-plus was specifically adapted for the ABB YuMi dual-arm cobot.
Prototype collaborative gripper uses multiple sensor systems, visual feedback, a built-in touchscreen interface, and other advanced features to deliver higher levels of human-robot interaction.
"Our grippers are plug and play," says Walderich. "You don't need any adapter plate and the electrical connection is already provided so you can connect it right at the wrist. You don't have to run a cable along the arm to wire it into the controller."
SCHUNK stocks the Co-act grippers with different mechanical and electrical connections, making them plug-and-play ready for the different robot brands. Walderich says the gripper is easy to integrate and control.
"We use discrete signals to control it, simple 24-volt signals," he says, explaining that by using discrete signals, there's no need for software drivers. "You only need one signal to open the gripper and one signal to close. Every robot already comes with a digital output that can open and close our gripper."
The Co-act grippers are best suited for material handling, machine tending, and simple assembly tasks.
More Sensors, More Collaboration
Sophisticated sensors will bring a whole new level of smarts to the SCHUNK Co-act gripper family.
The Co-act JL1 prototype gripper has a suite of sophisticated sensors to track the proximity of humans and trigger evasive movements to avoid direct human contact. A capacitive sensor creates an electric field around the gripper to detect when anything containing a lot of water enters this field. That way it can distinguish between a workpiece and a human body part. And it can do it within a narrow radius of 20 cm. If a human hand comes within proximity, the gripper automatically switches into safe operating mode.
Robot grippers designed for human-robot collaborative operation load and unload metal parts in a CNC machine tending application.
A force-moment sensor detects unexpected force effects, such as a collision or malfunction. It also allows for manual guidance, positioning and teaching. Tactile sensors in the fingertips give the gripper a sense of touch. Then it can determine the exact gripping force acting on an object, allowing it to apply the appropriate amount of force for fragile items.
The prototype gripper has built-in 3D cameras to help detect workpieces. An on-board touchscreen provides direct communication with the gripper for teaching or switching operating modes. Two different gripping types, parallel and angular, allow the JL1 to handle objects with varied geometries.
These advanced capabilities will help enable the agile manufacturing environments required for Industry 4.0 and beyond, where humans and robots work collaboratively.
Ease of Use, Flexibility for SMEs
On Robot grippers were designed with collaborative applications in mind. The startup likes to say that its grippers are built for "plug-and-produce" automation. This is especially advantageous for small and midsize enterprises with low-volume, high-mix production that need to stay agile as needs change.
The electric 2-finger parallel grippers have on-board smarts enabled by software. This not only limits the force for use in human-robot collaborative applications, but also makes the servo grippers easy to integrate and implement.
"Beyond safety, there's also the ease of use," says Kristian Hulgard, VP of Sales -- North America for On Robot A/S headquartered in Odense, Denmark. "When we go out and demo the product, it's ready to pick and place items in 5 to 10 minutes. We cut a lot of engineering and programming hours out of the installation. That's a huge part of what makes it collaborative."
A dual gripper enables the collaborative robot arm to handle more parts at a time, increasing productivity in this CNC machine tending application.
Hulgard says the CNC machining space is a huge market for collaborative robots, where cobots are often used to load and unload the machines.
"They are running 200 parts one day and then 300 parts the next day," explains Hulgard. "With our smart gripper, the flexibility comes with being able to grab different sizes of objects with different force. You simply enter the size of the item you want to grab and how much force you want to apply, and away you go. The option to change the gripper's functionality is a game changer. The return on investment is about 3 to 4 months. It's easy to see the value in that."
Software-Enabled Smart Gripping
Currently, On Robot's intuitive software interface is available for use with the Universal Robots UR series of cobots. On Robot grippers are part of the UR+ Solutions program for end effectors and other products certified for plug-and-play compatibility with UR cobots.
"You can mount our gripper on any robot you want and it will work. But where we see the value is how you control the gripper in the software," says Hulgard. "Right now, the software is only for Universal Robots, but we will introduce that software for other robot brands in the future."
By mounting the cobot on a mobile base, the customer can easily move the machine tending station from one CNC machine to another and handle a wide range of components of varying shapes and sizes. The On Robot gripper is able to determine whether it's gripping part A, B or C by detecting the different widths of the parts.
With a lot of development and a little tweaking, software is making grippers smarter and more adept.
Clever Grasping via the Cloud
RightHand Robotics' "RightPick" piece-picking solution relies on a host of intelligent hardware and software technologies. A compliant, rubber-jointed fingered hand with a suction cup grasps various items with the aid of 3D depth cameras and other sensors. The fingers help stabilize an item, so you can achieve a faster cycle time and pick heavier items. Computer vison helps the system figure out how to grasp the item. Artificial intelligence, specifically machine learning, is applied to improve the grasps over time. Data is shared with other robots via the cloud.
Robotic piece-picking solution for intralogistics combines innovative grasping technology, intelligent sensors, computer vision, and machine learning to automate individual item picking in plants.
"That's really where the magic is. It's about the datasets. We don't think the winning proposition is training a robot on each different item. We think the value is in training a more general set of capabilities. We can take something we've never seen before and based on our experience, pick that up effectively," says Leif Jentoft, one of the cofounders of RightHand Robotics, Inc. in Somerville, Massachusetts.
Grasping our Collaborative Future
Smart robot grasping has become a multidisciplinary endeavor. Solutions are coming from all corners of the engineer's toolbox. Mechatronics, soft robotics, sensor technology, intuitive software, and now AI and cloud robotics -- all are having an impact. The future will be collaborative at every level.
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