Robots work to aid humans
The industry is moving toward using collaborative robots (cobots) with force-sensing technology that work alongside people
The relationship between humans and robots has evolved since the early days of industrial automation. When the first robots hit automotive assembly lines in the late 1970s, a robotic cell was an island unto itself — a wide area that people avoided during operation. Today, people work side-by-side with robots in many industrial applications, creating more productive lines, safer conditions and happier employees (see Figure 1).
This evolution has happened because of continual technological advances, including electric servo motors, advanced control software, state-of-the-art human-machine interfaces (HMIs) and safety components.
In the beginning
The first industrial robots were not built with human interaction in mind. Cells contained large areas on the shop floor, surrounded by fencing to cover the radius of a robot’s possible reach. Even if a robot wasn’t working directly in an area, that space needed to be sectioned off because the robot had the reach capability to breach that zone. At that time, there was no software to prevent the robot from using its full reach in all directions.
In the 1980s, electric servo-driven motors replaced hydraulic cylinders in robots (see Figure 2). This allowed robots to be in the feedback loop so they could sense force and be more accurate to control. Using newly developed software, a work envelope could be created for just the path where the robot was moving to do its task, thus reducing the required amount of fenced-in space.
Over time, the big fencing created a fear for some people that robots were extremely dangerous because many people misunderstand how robots work. Robots don’t provide those subtle indicators, giving people the sense that robots can be unpredictable. These fears are unfounded.
With the evolution of HMIs, more people are communicating directly with robots. HMIs have advanced from elementary push-button pendants to intuitive touchscreen tablets, making it easy to interface with robots. The early robots required a specially trained person with an engineering background to program them (see Figure 3).
Modern HMIs progressed from simple touchscreens to wireless tablets with graphical icons so user-friendly that even an unskilled operator can program the robot to work with the next part or to set up a different job (see Figure 4).
Cameras and vision systems
Robots once needed all inbound parts to be fixtured or oriented identically, which usually required a person to manually load those parts. Today’s cameras and vision systems allow robots to handle a variety of parts in different positions. Three-dimensional vision systems give robots the ability to pull different parts from a bin and compensate for the differences before loading into the system. An operator may only need to push a bin of parts up to the inbound side of a robot and then remove finished parts at the end of the line. While the robot is handling the dull, simple tasks, operators can work multiple lines, do different tasks and learn a variety of skills (see Figure 5). Reducing the repetitive jobs like loading and unloading parts gives workers a stronger sense of engagement and less chance of injury, resulting in happier, healthier employees overall.
Today, the industry is moving toward using collaborative robots (cobots) with force-sensing technology that work alongside people. By sensing force and stopping a robot immediately upon contact, the system may no longer need fencing, and the footprint shrinks (see Figure 6). Now robots work directly in tandem with people for a variety of applications that involve ergonomic challenges, safety concerns and repetitive motions. For example:
- Machine manufacturing: a robot holds and rotates a large, heavy machine part so an operator can weld and grind on that part
- Machine tending: an operator continually loads parts onto a grid plate so a robot can simultaneously remove parts to load into a machine
- Auto assembly: a robot lifts and positions a spare tire for a worker to load into a car trunk
- Metal fabrication: a robot holds a tray, a person loads parts onto the tray, then the robot inserts the tray into a furnace.
Robots and maintenance
A maintenance technician’s relationship with robots has changed significantly over time. Real-time monitoring and remote access to a robotic system allows the maintenance team to oversee operations while performing other functions. Essentially, the robot is continually reporting on itself. A system will identify a problem, create an alert on a technician’s device and provide diagnostics immediately, reducing downtime it would otherwise take to investigate a cause and identify the way to fix it.
To go one step further, monitoring systems can indicate a part is wearing excessively and predict when it will fail, allowing the manager to schedule downtime to replace it and avoid interfering with productivity. Long-term system data helps create regular maintenance intervals and identify bigger problems that need to be addressed.
By preventing emergency repair situations and reducing the time to diagnose a problem with the robot, maintenance personnel can be more proactive and focus on the most important tasks in the facility.
A certified robotics integrator will perform a risk assessment of any new or modified robotic system following safety standards set by the Robotics Industry Association (RIA). This is especially important with collaborative robotic systems with increased potential contact points. Trained assessors look at how people may interact with robots during required tasks and evaluate the hazards.
After appropriate assessment, the integrator will design the proper safety measures into the system, such as safety interlocks, sensors, switches, scanners and light curtains. Safety software creates zones in the robot to monitor those safety inputs and lets the operator safely enter a zone. If safety signals are violated in that zone, the robot immediately stops. This allows robots and humans to continue working in harmony.