MSNBC recently published an article attributing the significant increase in worker productivity to the use of robots: (click here to read the article)

Indeed robots are extremely effective at improving productivity and product quality. However, unsafe work practices, such as unauthorized entry into a robot cell or inadequate interlocks can and do result in serious injuries and fatalities. The best practice is to lockout the main electrical disconnect as well as any other energy sources when entering a robot cell. This is sometimes not feasible due to the need to perform repetitive, routine tasks inside the robot cell while the power remains energized. When this is the case, a robot risk assessment is needed to ensure there are adequate safeguards to protect workers. This risk assessment should be performed based upon the requirements specified in ANSI/RIA R15.06-1999: Industrial Robots and Robot Systems – Safety Requirements.

The risk assessment includes identifying every employee job task requiring entry into a robot cell while the equipment remains energized; frequency of occurrence; and existing safeguards (e.g., interlocks). As risk increases so does the category of interlock:

Category Circuit performance
R2A            Control reliable
R2B            Single channel with monitoring
R2C            Single channel
R3A            Single channel
R3B            Simple
R4              Simple

After performing the risk assessment, it may be determined the existing category of interlock is sufficient. Otherwise, the interlock needs to be upgraded based upon the table listed above.

Several of my clients require a risk assessment be performed on every new robot prior to initial use to ensure worker safety.

Jon