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 cobots, and it provides the researcher with the possibility of using cobots for different projects and even share cobots between different research teams.
Many robotics manufacturers are offering cobots that can be used for research projects. Researchers can now choose the cobot that best fits their projects rather than simply adopting what is available in the market.
Below are some key options and capabilities researchers should consider while selecting cobots.
Key specs of cobots for research projects
Degrees of Freedom: Also called DoF or number of axes, this basically defines the number of independent displacements or aspects of motion a cobot is capable of. Most cobots have six or seven DoFs. The human arm 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, then a 6-DoF cobot 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 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. The same goes for the total reach of the cobot. Please be mindful 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.
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 about its 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.
Ecosystem: 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 ecosystem that 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 it’s 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’s electrical within the mobile platform body. Not all cobots offer this option.
About the Author
Shahab Khokhar is Business Manager, Components, at Clearpath Robotics. He is responsible for the P&L of the Components Business Unit and heads up new product selection and sourcing, vendor management, e-commerce store management, marketing and sales.
Clearpath Robotics is leader in self-driving robots for research and industry. Based in Kitchener, Canada, Clearpath Robotics was founded in 2009 by a group of four University of Waterloo graduates.