How to choose a Cobot for your research project
Collaborative Robots (Cobots) have been one of the most visible success stories of robotics and automation over the last few years.
With their intrinsic qualities and ease of integration, Cobots are being adopted in commercial and research projects worldwide.
Your research project may have a narrow scope for now but it may morph into something more demanding or you may want to use your Cobot for different research projects. Versatility is a key attribute of the Cobots and it provides the researcher with the possibility of using the Cobot for different projects and even share the Cobot between different research teams.
Many new and existing robotics manufacturers are offering Cobots that can be used for research projects. Researchers can now choose the best fit Cobot for their projects rather than adopting what is available in the market.
Here are some of the key options and capabilities that researchers should look for while selecting a Cobot:
Degrees of Freedom: Also called DoF for short or number of axes. DoF basically defines the number of independent displacements or aspects of motion that a Cobot is capable of. Most Cobots have 6 or 7 DoFs. The human arm for example has 7 DoFs, so if your project involves mimicking or understanding human arm movements then you need to pick a Cobot with 7 DoFs. If your project involves picking or sorting etc. then 6 DoF Cobots would suffice in most cases unless reaching the object requires complex movement of the Cobot.
Payload & Reach: This is a simple one, most Cobots have payload capacity ranging from 3 KG to 16 KG. However, you need to take a deeper look to see if it includes the necessary end of arm tooling, how heavy is the gripper that you want to use? Is the payload calculated at the maximum reach of the arm? It is best to leave some margin for future payloads while deciding on maximum payload capacity. Same goes for the total reach of the Cobot. Please be mindful that the Cobot movement may be limited at maximum reach.
Communication Rate: This will come into play for some typical research projects. For example if you are working on Human Robot Interaction (HRI) or any other project that requires near instantaneous communication, you may want to look at the Communication Rate of the Cobot. Some Cobots offer 1KHz rate as an option which effectively means a 1ms response time. This is ideal for near instantaneous communication.
ROS: Robot Operation System (ROS) is one of the most popular platforms for researchers. It is an open source platform with an extensive set of published libraries and support. Many researchers prefer ROS as it can provide them with a single interface to work with as all of the components like Cameras, LiDARs, GPS, IMUs etc. can work on ROS.
Not all Cobots offer out of the box ROS capability and support. If your project is ROS based please ask the Cobot provider for their ROS support. You can also search GitHub and Ros.org for this information.
Force/Torque Sensing: Some Cobots have Force/Torque sensing built into each joint. All Cobots offer external Force/Torque sensing capability. Having sensors in each joint is very helpful if your research entails getting force feedback. An end of arm external sensor will provide feedback only when the arm touches an object through that sensor. It would not provide feedback if the elbow or some other part of the Cobot comes into contact with any object.
Eco-System: You would definitely want to spend time and resources on your research and not on worrying about how to run the Cobot. Some Cobot manufacturers have an extensive Eco-System which includes third party hardware & software solutions and support. You can also find Research App Bundles from some Cobot manufacturers that can save you time and money.
Safety: Most Cobots have similar safety standards. Depending upon your project and how the Cobot interacts with humans you should look at the safety mechanisms and options like safety stop buttons, fall back capabilities etc. If you would like to use the Cobot for collaborative and non-collaborative projects then its best to opt for a Cobot that provides an option of turning off the collaborative mode.
If the Cobot is going to work close to humans you may want to look at the options for external e-stops and the stopping time of the Cobot once that switch is activated.
Mobility: Most Cobots can be easily integrated with mobile platforms. If you want a seamless integration with a mobile platform look for OEM options that some Cobot manufacturers provide. This enables stripping down of the control cabinet and installation of the Cobot electricals within the mobile platform body. Not all Cobots offer this option.
Please feel free to reach out with any specific questions regarding Cobot selection for your research projects.