Exercise 7. Industrial Application Simulation Using a Rotary Carousel EXERCISE OBJECTIVE

Transcription

1 Exercise 7 Industrial Application Simulation EXERCISE OBJECTIVE In this exercise, you will learn how to use the Rotary Carousel, Model You will experiment with its various features. You will use the Rotary Carousel to move objects and detect them with a limit switch. The output signal of the limit switch will be used to trigger a control instruction in the program. DISCUSSION A rotary carousel is a rotary conveyor. It is often used to move an object from one robot to another in a small area. The Rotary Carousel of your training system is shown in Figure 7-1. It is driven by a stepper motor mounted in the base. It can rotate either in the clockwise or counterclockwise direction. PLATTER CURSOR DISK DETECTION ZONE LIMIT SWITCH ACTUATOR Figure 7-1. Rotary Carousel As shown in Exercise 3, the number of degrees a stepper motor rotates depends on the degrees per step characteristic of the motor. For the stepper motor of the Rotary Carousel, this characteristic is "1.8". 7-1

2 However, the number of degrees the platter of the Rotary Carousel rotates is not only determined by the motor characteristic, it is also determined by the ratios of the gears that drive the platter. If you look at the gears under the platter, you will note that two gear ratios must be considered: the motor gear to intermediate gear (ratio 1), and the intermediate gear to platter gear (ratio 2). The degrees per step characteristic of the Rotary Carousel expressed in equation form is as follows: degrees (motor degrees/step) (ratio1) (ratio2) step teeth 12 teeth 72 teeth 108 teeth As an example, the number of steps required for the platter to rotate 90( is 1619 (90 degrees/ degrees per step). The operation of the Rotary Carousel is controlled as shown in Table 7-1. Action Rotate the Rotary Carousel in the clockwise or counterclockwise direction Teach Pendant-Controlled Robot System Model 5100 Key on the Teach Pendant Extrnl Mtr + and Extrnl Mtr - Computer-Controlled Robot System Model 5150 Command in the Robotus Application Carousel Table 7-1. Control instructions. Limit Switch The Rotary Carousel is provided with a limit switch. The limit switch is used to detect the presence of objects on the platter. Procedure Summary In the first part of the exercise, Set-up, you will install and connect the Robot Training System and the Rotary Carousel. In the second part of the exercise, Experiment with the Rotary Carousel, you will experiment with the operation of the Rotary Carousel. In the third part of the exercise, Additional Experiment, you will simulate a galvanizing process. A film canister will be used as a steel piece to be galvanized, and the metallic cylinder will be used as a zinc bath. 7-2

3 In the last part of the exercise, Shutdown procedure, you will shut down the system. EQUIPMENT REQUIRED Refer to the Equipment Utilization Chart, in Appendix A of this manual, to obtain the list of equipment required to perform this exercise. PROCEDURE CAUTION! When you work with moving equipment, make sure you are not wearing anything that might get caught, such as a tie or jewelry. If your hair is long, tie it out of the way. Avoid touching the stepper motors. They get hot. Set-up * 1. Install the Articulated-Arm Robot and the Rotary Carousel as shown in Figure 7-2. * 2. Connect the equipment as shown in Appendix B. For detailed instructions, refer to the User Guide of your training system. * 3. Connect the Rotary Carousel cable to the ACCESSORY output on the base of the Articulated-Arm Robot. Make sure the connector is all the way in. * 4. Connect the normally open terminal (NO) of the limit switch to TTL input 1. Connect the common terminal of the limit switch to the common terminal of TTL input

4 FILM CANISTER R0 R6 R7 PLATTER R8 R9 R10 R11 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 C0 Figure 7-2. Location of the equipment on the work surface. Experiment with the Rotary Carousel * 5. Turn the Power Supply on. Note: Suggested name for this program: EXE_7_A. * 6. Create a program that causes the platter to rotate 90( in the clockwise direction, then rotate 90( in the counterclockwise direction to return to its original position, and stop. Note: You may use the cursor disk on the Rotary Carousel to indicate the starting position of the platter. Refer to the User Manual of your training system to learn how to control the Rotary Carousel if necessary. * 7. Once your program is completed, tested, and debugged, save it. 7-4

5 Additional Experiment 1 Note: Suggested name for this program: EXE_7_B. * 8. Create a program that causes the platter to rotate in the clockwise direction, then change direction when the limit switch is actuated by an object (film canister). Then the platter rotates 180( in the counterclockwise direction and stops automatically. Note: Place some coins in a film canister to add weight, and place it on the platter of the Rotary Carousel as shown in Figure 7-2. The coins will prevent the film canister from slipping on the platter. * 9. Once your program is completed, tested, and debugged, save it. Additional Experiment 2 Simulation of a Galvanizing Process Galvanizing is a process by which the surface of an iron or steel piece is covered by a layer of zinc to prevent corrosion. One method of galvanization consists in dipping the piece in a bath of molten zinc (hot dip galvanization). You will create a program that simulates an articulated-arm robot that picks up a steel piece, dips it in a zinc bath, and places it on a carousel platter. Then the carousel will start to rotate. It will stop rotating when a sensor detects the presence of the galvanized piece. The film canister will simulate the steel piece to be galvanized and the metallic cylinder will simulate the zinc bath in which the steel piece is dipped. Note: Suggested name for this program: EXE_7_C. * 10. Place manually the film canister with a few coins in it at position (R8,C6), and the metallic cylinder, with the opening on top (without lid), at position (R7,C2), as shown in Figure

6 R0 R6 R7,C2 R7 R8 R8,C6 R9 R10 R11 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 C0 Figure 7-3. Location of the equipment on the work surface. * 11. Perform a home positioning. Record the point. With the Articulated-Arm Robot, pick up the film canister and dip it in the metallic cylinder as shown in Figure 7-4. Do not dip the film canister deeply in the film canister. Since this operation requires precision, the speed should be set very low. * 12. Take out the film canister from the metallic cylinder, and place it on the platter of the Rotary Carousel in the detection zone of the limit switch. Note: The detection zone of the limit switch ends at the black circle on the platter. * 13. Perform a home positioning. * 14. Start the rotation of the platter in the clockwise direction and stop it when the limit switch is actuated by the film canister. 7-6

7 Figure 7-4. Dipping the film canister in the metallic cylinder. * 15. With the Articulated-Arm Robot, complete your program by picking up the film canister (stopped at the limit switch) on the platter, and then by moving it to its original position (R8,C6). Once the film canister is positioned on the work surface, open the gripper and return the Articulated-Arm Robot to the home position. * 16. Once your program is completed, tested, and debugged, save it. * 17. Set the execution of your program for three repetitions. Shutdown Procedure * 18. Turn the Power Supply off. * 19. Disconnect the system and return the equipment to its storage location. 7-7

8 CONCLUSION In this exercise you were introduced to the Rotary Carousel operation. You learned how to control the Rotary Carousel, and how to use the output signal of the limit switch to trigger a control instruction in a program. REVIEW QUESTIONS 1. Which elements determine the actual degree of movement per step performed by the platter of the Rotary Carousel? 2. Determine the number of steps required for the Rotary Carousel of your training system to rotate 270( in the counterclockwise direction. 3. In the program EXE_7_B, explain what causes the rotation direction of the platter to change. 4. What is a rotary carousel often used for? 7-8

9 5. What is the limit switch used for on the Rotary Carousel? 7-9