COLLABORATIVE, ROBOTIC WORKCELL

For Real World Manufacturing

Introduction

According to the International Federation of Robotics (IFR), 2014 was a record year for robot deliveries with over 225,000 units delivered worldwide – an increase of 27% over the previous year (see Figure 1). Over 62% of these deliveries went to countries in Asia led by China (40%), South Korea (28%), and Japan.[i]

Figure 1: Worldwide Robot Sales

Figure 1: Worldwide Robot Sales

In their most recent market study, the Boston Consulting Group (BCG) speculates that several key factors are responsible for this spike in robot sales. One significant factor sited by the study is the rising cost of labor around the world, which has caused manufacturers to take steps to increase their output per worker in order to stay competitive.  In addition, BCG sites advances in peripheral technologies like machine vision and end effector systems as enabling robots to perform more complex tasks at a significantly lower price point than ever before.[ii] In addition to these factors, the introduction of low cost, easy to program, “collaborative” robots has expanded the potential market for “robot systems” to much smaller manufacturers who traditionally did not have the engineering support for this type of automation.  The ability of these robots to be “taught” a task by a worker on the manufacturing line without the need for traditional programming allows them to be deployed quickly and cost effectively.[iii]

Collaborative Robot Examples

Figure 2: Collaborative Robot Examples

Figure 2: Collaborative Robot Examples

Figure 2 presents examples of collaborative robots currently on the market.  Although different in terms of configuration, all of these robots are characterized by their ability to work alongside humans without the need for additional safety shielding.  This is accomplished through the use of lightweight materials, the elimination of sharp edges, and sophisticated sensor networks which constantly monitor the forces encountered by the robot arm during its task execution.  The speeds and payloads of these robots are usually limited to allow the system to be quickly brought to a stop in the event of unexpected encounters with workers or workplace obstacles. 

In addition to the above mentioned safety features, the collaborative robots shown in the figure are all intended to be used directly by factory floor workers without the need for sophisticated programming.  Instead, the robots are “taught” each task by manually moving the arm joints to their desired configuration for each step in a production process.  The robot is able to remember the taught points and then repeat the process indefinitely.

Applicable Safety Standards

The safety standards for industrial robots and robotic systems are defined by the International Standards Organization (ISO) as ISO 10218-1 and ISO 10218-2 respectively. The first standard covers just the robot itself and does not account for the specific task the robot is performing or the tools (end effectors) that are required. These system related factors are covered in ISO 10218-2. The important point here is that although a robot may be considered “collaborative”, the function of the entire workcell must be considered when evaluating the safety of the complete system.  In other words, the use of a “collaborative” robot does not guarantee the safety of the entire system.

As mentioned above, the specific end effector used for a given task can have a significant effect on the safety requirements for the system. For example, equipping a robot (even a “collaborative” one) with a welding head or a spray gun results in a system which requires additional protection to provide safety to nearby workers.

Figure 3 Worcell with Optional Rotary Table

Figure 3 Worcell with Optional Rotary Table