Unit 14 Competency 1 - Design and write a program for controlling a robot

Suggested Objective a: Analyze the factors for implementing robots in modern factories

 

With more companies looking for lean manufacturing Links to an external site. solutions, industrial manufacturing robots Links to an external site. provide many benefits Links to an external site.that companies require to stay competitive. The speed, repeatability, and efficiency thatindustrial robots Links to an external site. provide can increase productivity and profits, reduce costs, and keep jobs in the United States.

Productivity and Profits

With no need to take breaks and the ability to work 24/7, a manufacturing  Links to an external site.robot can increase productivity dramatically. Higher rates of throughput mean higher profits.Manufacturing  Links to an external site.robots help produce products much faster than traditional manufacturing Links to an external site.methods by decreasing part cycle times. The very nature of manufacturing  Links to an external site.robots lends itself to creating a leaner, more efficient manufacturing cycle.

Reduced Costs

Industrial manufacturing robots do not require an hourly wage. Other than the cost of maintenance Links to an external site., a company pays for a manufacturing robot once. The initial cost of an industrial manufacturing robot can seem daunting, but the return on investment (ROI Links to an external site.) can quickly be realized after implementation. A company can expect a ROI Links to an external site. on their industrial manufacturing robot in six months to one year.

Also, manufacturing robots provide better quality parts. For example, an arc welding Links to an external site. robot provides high quality weld seams, making the weld strong and the part more durable. Because of high repeatability, reworking time is nearly eliminated when using manufacturing robots.

Keeping Jobs in the United States

The myth that the implementation of industrial robots Links to an external site. in manufacturing will lead to massive unemployment is just that - a myth. The fact is that many companies that want to cut costs consider both outsourcing jobs to countries with cheaper labor costs and integrating industrial robots Links to an external site. into their production lines. Cost analyses have confirmed that outsourcing jobs and integrating robots provide about the same amount of savings, almost 60% in some cases. The benefits of integrating manufacturing robots and not outsourcing labor are that jobs will stay in the United States and product quality will actually improve. A manufacturing robot can typically produce parts at a much higher quality than outsourced labor.

Fears about Loss of Labor

As for the notion of manufacturing robots replacing workers, this is true to some extent. However, the jobs that are replaced are tedious, monotonous, and possibly dangerous jobs. Lifting heavy pieces onto a table or skid for eight hours a day can result in injuries and other health problems. A manufacturing robot can do the same work without putting humans in harm's way. The jobs that are lost to robots are minimal and counteracted by the opportunity of new Links to an external site. positions in the company. Instead of moving heavy parts, a worker can learn to program or perform maintenance on the manufacturing robot. In total, robots in manufacturing do not always result in a net loss of labor.

 

Watch the video of the bag gripper robot for pallets using the link below.

Information copied from http://www.robots.com/faq/show/what-are-the-advantages-of-an-industrial-manufacturing-robot Links to an external site.on December 15, 2014.

 

Suggested Objective b:  Evaluate safety issues of working with robots in manufacturing

 

Industrial robots are programmable multifunctional mechanical devices designed to move material, parts, tools, or specialized devices through variable programmed motions to perform a variety of tasks. Robots are generally used to perform unsafe, hazardous, highly repetitive, and unpleasant tasks. They have many different functions such as material handling, assembly, welding, machine tool load and unload functions, painting, spraying, and so forth.

Studies indicate that many robot accidents occur during non-routine operating conditions, such as programming, maintenance, testing, setup, or adjustment. During many of these operations the worker may temporarily be within the robot's working envelope where unintended operations could result in injuries.

There are currently no specific standards for the robotics industry.

Information copied from https://www.osha.gov/SLTC/robotics Links to an external site. on December 15, 2014.

Check out the Morals and the Machine Links to an external site. site from Economist.com.  It has a video regarding robotics and safety.  Information is available for reading as well.

http://www.economist.com/node/21556234 Links to an external site.

 

Suggested Objective c:  Analyze how robots are programmed for specific functions

 

Image copied from http://techweet.com/robotics-engineer.html Links to an external site. on December 15, 2014

Industrial robots are programmable multifunctional mechanical devices designed to move material, parts, tools, or specialized devices through variable programmed motions to perform a variety of tasks. An industrial robot system includes not only industrial robots but also any devices and/or sensors required for the robot to perform its tasks as well as sequencing or monitoring communication interfaces. 

Robots are generally used to perform unsafe, hazardous, highly repetitive, and unpleasant tasks. They have many different functions such as material handling, assembly, arc welding, resistance welding, machine tool load and unload functions, painting, spraying, etc. See Appendix IV:4-1 Links to an external site. for common definitions. Most robots are set up for an operation by the teach-and-repeat technique. In this mode, a trained operator (programmer) typically uses a portable control device (a teach pendant) to teach a robot its task manually. Robot speeds during these programming sessions are slow.

Robot Programming By Teaching Methods. A program consists of individual command steps which state either the position or function to be performed, along with other informational data such as speed, dwell or delay times, sample input device, activate output device, execute, etc. When establishing a robot program, it is necessary to establish a physical or geometrical relationship between the robot and other equipment or work to be serviced by the robot. To establish these coordinate points precisely within the robot's working envelope, it is necessary to control the robot manually and physically teach the coordinate points. To do this as well as determine other functional programming information, three different teaching or programming techniques are used: lead-through, walk-through, and off-line. 

1. 1. Lead-Through Programming or Teaching. This method of teaching uses a proprietary teach pendant (the robot's control is placed in a "teach" mode), which allows trained personnel physically to lead the robot through the desired sequence of events by activating the appropriate pendant button or switch. Position data and functional information are "taught" to the robot, and a new program is written (Figure IV:4-3). The teach pendant can be the sole source by which a program is established, or it may be used in conjunction with an additional programming console and/or the robot's controller. When using this technique of teaching or programming, the person performing the teach function can be within the robot's working envelope, with operational safeguarding devices deactivated or inoperative. 
      
      FIGURE IV:4-3. ROBOT LEAD-THROUGH PROGRAMMING OR TEACHING
      
      
   
   
   1. Walk-Through Programming or Teaching. A person doing the teaching has physical contact with the robot arm and actually gains control and walks the robot's arm through the desired positions within the working envelope (Figure IV:4-4). 
      
      
      FIGURE IV:4-4. WALK-THROUGH PROGRAMMING OR TEACHING
      
      
      
      During this time, the robot's controller is scanning and storing coordinate values on a fixed time basis. When the robot is later placed in the automatic mode of operation, these values and other functional information are replayed and the program run as it was taught. With the walk-through method of programming, the person doing the teaching is in a potentially hazardous position because the operational safeguarding devices are deactivated or inoperative. 
      
      Off-Line Programming. The programming establishing the required sequence of functional and required positional steps is written on a remote computer console (Figure IV:4-5). Since the console is distant from the robot and its controller, the written program has to be transferred to the robot's controller and precise positional data established to achieve the actual coordinate information for the robot and other equipment. The program can be transferred directly or by cassette or floppy discs. After the program has been completely transferred to the robot's controller, either the lead-through or walk-through technique can be used for obtaining actual positional coordinate information for the robot's axes. 
      
      
      FIGURE IV:4-5. OFF-LINE PROGRAMMING OR TEACHING
      
      
      
      When programming robots with any of the three techniques discussed above, it is generally required that the program be verified and slight modifications in positional information made. This procedure is called program touch-up and is normally carried out in the teach mode of operation. The teacher manually leads or walks the robot through the programmed steps. Again, there are potential hazards if safeguarding devices are deactivated or inoperative. 
   
   Degrees of Freedom. Regardless of the configuration of a robot, movement along each axis will result in either a rotational or a translational movement. The number of axes of movement (degrees of freedom) and their arrangement, along with their sequence of operation and structure, will permit movement of the robot to any point within its envelope. Robots have three arm movements (up-down, in-out, side-to-side). In addition, they can have as many as three additional wrist movements on the end of the robot's arm: yaw (side to side), pitch (up and down), and rotational (clockwise and counterclockwise).

    

Information copied from https://www.osha.gov/dts/osta/otm/otm_iv/otm_iv_4.html Links to an external site.on December 15, 2014.

How Robots Sense, Plan, and Act Links to an external site.

Robots that Learn from People Links to an external site.