Manufacturing in Industry 4.0 necessitates rapid, proactive responses to ever-changing consumers’ demands. This has led to a new trend of mass customization in certain aspects of the products, depending on their preferences and needs.
To meet the expectations and the requirements of individual customers, the manufacturing process must gain a great degree of flexibility without compromising sustainability, production efficiency, and quality throughout the product life cycle to maintain a competitive edge.
Industrial robots are truly capable of maintaining high efficiency and repeatability for mass production, but they lack the flexibility to deal with uncertainties resulting from mass customization. While humans, in such situations, can deal with such uncertainties and variability, they are restricted by their physical capabilities in terms of repeatability, physical strength, stamina, speed, etc.
A balance of automation and flexibility that combines the benefits of robots and human labor is thus required to achieve these overarching manufacturing goals during mass customization. Here is where Human-Robot Collaboration (HRC) emerges as a promising discipline that enables robots and humans to operate jointly to complete collaborative tasks.
What is a collaborative robot (cobot)?
A collaborative robot or cobot is a robot designed to collaborate with human workers. The purpose is to support the works within a defined collaborative workspace. They serve as tools for operators, not devices that replace human workers. Cobots typically mimic human actions and carry out repetitive or injury-prone tasks at similar or slower speeds, while the workers perform higher-value manual tasks. Typical cobots comprise small-footprint robotic arms only. They are safe for people to work with and around (i.e., no need for protective fencing) and are easy for ordinary operators to program, deploy and re-deploy.
Some of the key scenarios of human-robot collaboration (HRC) are as follows:
- Co-manipulation: In this scenario, the human worker and the cobot both hold and move an object. The human guides the object’s path, while the cobot handles the object’s weight.
- Handover: Here, the cobot safely hands objects to the human worker. Handover pace changes according to the human’s readiness to take an object.
- Assembly: It is a distributed action between the worker and the cobot, according to the expected workload.
- Pick-and-place: The cobot chooses objects to pick and place while accounting for distance, reachability, and the human’s predicted motion plans.
- Fetch: In this, the cobot fetches objects according to the human’s progress in the assembly task.
- Illumination: The cobot, with a light source mounted as a tool, provides direct illumination on the human’s workspace.
- Inspection: While the worker screws bolts in holes, the cobot inspects if all holes are screwed and issue a warning in case of a missing bolt.
There’s an argument for both industrial robots and cobots, but the decision to select depends on the application. Manufacturers must explore all of their robotic options and understand the pros and cons of different automation types to make the best long-term decision. This section will explore some of the key pros and cons of both cobots and industrial robots.
Cobots
Pros
- Cobots can share a workspace with human workers.
- Relatively simple to program, reprogram and integrate to the changing needs.
- Low primary cost for integration
- Less expensive than six-axis industrial robots
- No need for a safety cell or restricted area. This saves a lot of production floor space.
- Can achieve higher productivity without additional labor or extensive capital investment.
- Fast return on investment
Cons
- Since cobots are collaborative, they cannot work without human assistance and supervision.
- Limited reach, payload, speed, and accuracy.
- Not very powerful as most six-axis robots.
- Not suitable for high-speed and high payload applications
- Best fit in applications with lower payloads.
- Safety precautions can bring down productivity, result in very low operating speeds, and significantly increase integration costs.
- Thorough risk assessment is necessary to ensure safety measures
- Expensive fencing, if necessary, can cause substantial costs.
Industrial robots
Pros
- Industrial robots require less human supervision.
- Have a high-efficiency and high production rate.
- Ideal for handling tasks too risky for human workers
- Much faster, accurate, and precise than human workers, even with high payload
- Enable fully automated production lines that can handle applications at speeds that can’t be attained by humans
- Remove operators from unsafe or unclean environments
- Higher ROI due to the high rate of operation
- Has extensive programing and integration options
- It can be implemented in collaborative applications with appropriate risk assessment
Cons
- Not suitable for low volume production
- Require more space in the production floor due to fixed work cells
- Not easy to alter the processes
- Employees need the training to initiate, run and maintain the robot.
- Can add additional costs if outside resources are required for design changes, programing, or maintenance
- Adds system integration costs
