Well-designed robot grippers are the key to connecting robots with the world around them. Engineers have to consider many things when developing a robotic gripper design. They are complex pieces of machinery, from the precise motion to how force will be applied to objects.
Engineers typically use a few key steps to design robotic grippers, from concept to final production.
Engineers work through a detailed planning process before any prototyping or mockups. This is an important step in designing a robotic gripper. It establishes the specific task or tasks the machine will be used for and physical size and shape requirements. Engineers will usually work with the client or project manager to go over all these specifications.
At this stage, the design team usually chooses the type of gripper they want to use. There are several types they can select based on what it has to pick up. For example, a robotic gripper that has to gather metal pieces in an automotive assembly line might be magnetic.
Servo-electric robotic grippers use motors to perform their tasks. These streamlined, no-fuss grippers are connected to a computer that provides precise instructions. This allows the gripper to apply just the right amount of pressure on the objects it interacts with.
Pneumatic and hydraulic robotic grippers are similar but slightly different. Both use pressurization to operate the gripper and interact with objects.
Pneumatic grippers use pressurized air to accomplish this. A compressed air supply opens to move the gripper jaw. Precision is key, though — just the right amount of pressure needs to be applied, not too much and not too little.
Hydraulic grippers use a similar mechanical approach except with pressurized liquid instead of compressed air, hence the use of “hydro” in the name. The liquid pressure is adjusted to operate pistons that open and close the gripper carefully. Precision is crucial.
The final category of the most common robotic gripper types is vacuum and magnetic grippers. They aren’t particularly similar, but they are distinctly different from the options mentioned above. They use special surfaces on the gripper claw or interaction surface to pick up objects.
Vacuum grippers do this using suction. Like a consumer vacuum cleaner, these grippers use the force of air being sucked out of a space to lift objects. Magnetic grippers perform the same task using magnets. They can only work with magnetic metals, such as nickel or cobalt.
After the initial planning and concept phase, the next step in designing robotic grippers is choosing the specific components. This stage moves past the general type of robotic gripper, such as those mentioned above. Design teams can get into the details of how exactly it will work once they know what style they want to use.
How many fingers will it have, if any? How will it move? What jaw configuration will it use? These are all questions engineers will ask during the detailed design phase. For example, robotics engineers have explained that they consider things like the exact shape, size and material of the object the robot needs to pick up. They’ll also consider different actuators, controllers and sensors to determine how to control the robot.
A virtual mockup will often be created using CAD software during this part of the process. Designing robotic grippers is complex, so these tools can be extremely useful.
The design team can employ several configurations, assuming a claw-style gripper is used. Robotic gripper designs vary extensively, with different numbers and types of fingers and various motion styles. The amount of fingers will depend entirely on the object the machine is designed to interact with.
Engineers must also consider the jaw configuration of the robotic gripper design. This refers to how it applies force to the objects it picks up. There are two main types: friction and encompassing. Friction presses two straight surfaces against the object, relying on strength to hold it in place. Encompassing forms a hook-like shape to help grip the item with edges that curl underneath it.
Engineers can move on to analyzing the design to see how well it might work once they have a detailed robotic gripper design. Teams will have different preferred methods for conducting testing. Usually, though, designing robotic grippers requires force analyses and running simulations.
A force analysis will mathematically assess the forces a robotic gripper would apply on objects it picks up. Other simulations may be used to demonstrate how it would work in action. This helps the team spot any potential problems or flaws in their design before creating an actual physical prototype of the gripper.
After thorough digital testing, the robotic gripper design team will usually go ahead with a physical prototype or mockup. Today, these can be 3D printed. Many engineers use pre-existing components and would simply purchase a few of each one they need to create their prototype. This real-life version of the robotic gripper allows the design team to test their gripper on real objects where it might operate.
Some teams will also send in their prototype or design for application analysis. This is more common among businesses that might not have much experience working with robotics yet. An application analysis is a thorough testing process used to evaluate whether a robot is ideal for the specific process someone has in mind.
Robotics engineers will run several performance tests and conduct careful functional analyses. The result is a proof of concept detailing how well the robot and gripper would perform in their intended functions. The design team can use this information to polish and optimize their product to maximize effectiveness.
The design team is now ready to create a finalized design. It is important to note that engineers often go through numerous iterations of their robotic gripper before arriving at the final product. Each round of prototyping and testing helps the team find new ways to improve the gripper.
After the design is finalized, the team will be ready to scale up their item for real-world use. Robotic grippers are vital for countless applications today, such as industrial automation, space exploration and medicine. Dozens or even hundreds of the same gripper may be made for a single client. At this stage, the gripper is finally ready for integration into real robots where it will perform the task it was carefully designed to carry out.
The process of designing robotic grippers is complex but highly creative. Engineers must be able to think of innovative solutions to countless challenges they may face in the design process. Their product may even fail before the gripper works just right. These are incredible feats of engineering, carefully designed to use physics to change the world around them.