Interfacing a PUMA 500 Robot with a PC-based Controller · Yellow PUMA (ECE4007L01) iii EXECUTIVE SUMMARY The Unimation PUMA (Programmable Universal Machine for Assembly, or Programmable

Proposal

Interfacing a PUMA 500 Robot with a PC-based Controller

ECE4007 Senior Design Project

Section L01, Yellow PUMA Team

Josh Chao, Team Leader

Francis Fernandes

Denny Lie

Jackson Tanis

Submitted February 4, 2009

Yellow PUMA (ECE4007L01) ii

TABLE OF CONTENTS

Executive Summary ........................................................................................................ iii

1. Introduction ............................................................................................................... 1

1.1 Objective ......................................................................................................... 1

1.2 Motivation ....................................................................................................... 1

1.3 Background ..................................................................................................... 2

2. Project Description and Goals .................................................................................... 3

3. Technical Specification ............................................................................................... 4

4. Design Approach and Details ...................................................................................... 8

4.1 Design Approach ............................................................................................. 8

4.2 Codes and Standards ........................................................................................ 10

4.3 Constraints, Alternatives, and Tradeoffs........................................................... 10

5. Schedule, Tasks, and Milestones ................................................................................. 11

6. Project Demonstration ................................................................................................ 12

7. Marketing and Cost Analysis ...................................................................................... 14

7.1 Marketing Analysis .......................................................................................... 14

7.2 Cost Analysis ................................................................................................... 15

8. Summary ..................................................................................................................... 17

9. References .................................................................................................................... 18

Appendix A ...................................................................................................................... 21

Yellow PUMA (ECE4007L01) iii

EXECUTIVE SUMMARY

The Unimation PUMA (Programmable Universal Machine for Assembly, or

Programmable Universal Manipulation Arm) 500 robot is a six-axis articulating arm robot.

Applications such as welding, packaging, palletizing, and parts installation have been automated

using industrial robots for higher efficiency and productivity. Application engineering, design

experience, and enhanced manufacturing techniques have resulted in a powerful robot line with

longer reach and higher payload capabilities. The advanced design and flexibility of the robots

offer new opportunities for productivity and quality improvement in a wide range of

manufacturing operations.

Georgia Tech’s ME department has donated one such robot to the ECE department.

Currently the robot’s controller is not functioning and the task involves inspecting the

mechanical aspects of the robot and replacing the robot’s control system with a Rockwell

Automation controller. The next phase would involve setting up all the components – PC, control

system, motor drivers, motors, and the robot, to communicate and interface with each other.

Once these components are functioning, kinematic equations need to be programmed into the

control system in order to make the end effector of the robot move to a specified x, y, and z

coordinate with a specified rotational direction within an error of ± 1 cm and ± 3 degrees

respectively.

PUMA robots have six degrees of freedom and re-programming ability which allows

them to handle various tasks with software updates thereby reducing production cost. With all

the costs combined the robot is worth $13,447 per unit installation. With successful completion

of the robot, the functional system can be used as an automated measurement tool for research

and groundwork for future ECE student’s projects.

Yellow PUMA (ECE4007L01) 1

Interfacing a PUMA 500 Robot with a PC-based Controller

1. INTRODUCTION

Industrial robots are reshaping manufacturing industries [1]. Many applications, such as

welding, packaging, palletizing, and parts installation, have been automated using industrial

robots for higher efficiency and productivity. In particular, the six-axis articulating arm robots

are extensively used due to their wide range of motion and reach [2].

Georgia Tech’s ME department has donated one such arm robot, the Unimation PUMA

500, to the ECE department. The team members will inspect the mechanical aspects of the robot

and replace the broken control system with a Rockwell Automation controller. The functional

system can then be used as an automated measurement tool for research and groundwork for

future ECE student’s projects.

1.1 Objective

The Unimation PUMA 500 robot will be mechanically and electrically repaired. Dr.

Thomas E. Michaels, an Electrical and Computer Engineering professor, requested for the

robot’s motors to be inspected and the control system to be replaced with a Rockwell

Automation controller. Then, given a single or a series of inputs, the robot shall move its end

effectors to a specific position in the spatial coordinates.

1.2 Motivation

This project will give the team members a practical approach in building arm robot

control systems. This experience will prove to be useful for the team member’s future careers in

robotic industries, as articulating arm robots are widely used in manufacturing industries.


The functional system can be used by Dr. Thomas E. Michaels as an automated

measurement tool for research and groundwork for future ECE projects. In addition, the success

of this project will be useful for Rockwell Automation, as it proves that the Rockwell

Automation controller can be used to control Unimation PUMA 500 robots.

1.3 Background

Industrial Robots

As mentioned above, industrial robots are reshaping the manufacturing industries. North

American manufacturing companies have spent up to $877 million on industrial robots since

2003 [1]. Depending on the structures, industrial robots can be categorized into Selective

Compliant Assembly Robot Arm (SCARA), Gantry (Cartesian coordinate robot), and

Articulating Arm [3]. The articulating arm robots are widely used in manufacturing industries

due to their wide range of motion and reach [2].

Depending on the end effectors, an articulating arm robot can perform different tasks,

such as welding, assembly, painting, and packaging. Some of the commercial welding robots

include Panasonic VR-006, Motoman UP6, Fanuc, and ABB IRB 1600 [4].

Rockwell Automation Controller

Rockwell Automation is a global provider of industrial automation, power, control, and

information solutions. Brands in the industrial automation include Allen-Bradley and Rockwell

Software. In robotics industry, Rockwell Automation’s Programmable Automation Controllers

(PAC), such as CompactLogix system, ControlLogix system, and SoftLogix5800 controller, are

widely used. These controllers provide the reliability of a PLC, task flexibility, and computing

power of a PC for motion control. These PAC have built-in software called RSLogix 5000

(v.17), which supports kinematics control for multi-axes robots. The software eliminates the


expenses for additional robot controllers, software, and integration time in building the whole

robot system [5].

Other Related Research

The Unimation Puma 500 robot donated by the ME department was actually used for a

senior design project by two ME students in 1999 [6]. Although the focus of the previous project,

interfacing force or torque sensors on the robot, is irrelevant to the topic of this project, the

reports from the previous project might provide useful information about the technical

specifications and usage of the robot.

2. PROJECT DESCRIPTION AND GOALS

The Unimation PUMA 500 robot will be mechanically inspected and fixed, i.e. each of

the six motors in the robot joints. Next, the robot’s control system will be replaced with a

Rockwell Automation control system, which includes a Programmable Automation Controller

(PAC), motor drivers, and I/O module cards. After the robot and the controller are interfaced and

connected, the team members will program the robot to move its end effectors to a specific

position in the spatial coordinates. Once the system is built and functional, it will have the

following properties:

Functional motors in each of the robot joints

Interface connector between the robot and the controller

Compiled programs of kinematic principles to control the robot’s movement

The system will also meet the following goals:

Ability to move all of the six axes within the robot’s joint angles specification


Ability to read a single input and move the end effectors to a user-defined position

If time permits, the following goals shall be met:

Ability to read a series of inputs and move the end effectors to all of the specified

positions forming a trajectory

Ability to move to a position within an error of ± 1cm and ± 3 degree

3. TECHNICAL SPECIFICATIONS

The Unimation PUMA 500 robot has six revolute joints, and each joint is driven by a DC

servomotor. The orientation of each axis and the angle of rotation of each joint are shown in

Figure 1 and Table 1 [6]. The maximum static load at the tip of the end effectors is 25 N and the

maximum straight line velocity is 51 cm/sec. The arm is 86.6 cm long while the wrist is 5.6 cm

long shown in Figure 2. The height of the tower, i.e. the distance between the base of the robot

and Joint 2 in Figure 1, is 67.2 cm. The total weight of the robot is 54.4 Kg [7]. Detailed

technical specifications can be viewed in Table 2.


Table 1. Joints, Axis of Rotation, and Maximum Angle of Rotation

Joint Axis of Rotation Maximum Angle of

Rotation

Joint 1 – Waist Z 320°

Joint 2 – Shoulder X 250°

Joint 3 – Elbow X 270°

Joint 4 - Wrist Rotation Y 300°

Joint 5 - Wrist Bend X 200°

Joint 6 – Flange Z 532°

Figure 1. Schematic of Unimation PUMA 500 robot with joint angles,

axis of rotation, and maximum rotation range [6].


Figure 2. Schematic of Unimation PUMA 500 robot with dimensions of the robot in

inches [8].


Table 2. Detailed Technical Specifications of the Unimation PUMA 500 Robot

Axes 6 revolute axes

Configuration 6 degrees of freedom

Drive Electric DC servomotors

Power Requirement 110-130 VAC, 50-60 Hz, 1500 Watts

Repeatability ± 0.1 mm

Maximum Static Load 25 N

Maximum Straight Line Velocity 51 cm/sec

Reach

86.6 cm to the wrist

92.2 cm to the flange

Weight 54.4 kg

The motors will be driven by the Rockwell Ultra 3000 motor drivers [8]. The controller is

a ControlLogix PAC system by Rockwell Automation and can be connected to a PC and

programmed using the RSLogix 5000 programming language also developed by Rockwell

Automation [9].


4. DESIGN APPROACH AND DETAILS

4.1 Design Approach

The Unimation PUMA 500 robot needs a new control system and motor drivers, because

the old control system and motor drivers are not functioning. All six motor drivers of the

Unimation PUMA 500 robot will be replaced with the Ultra 3000 motor driver model number

2098-DSD-020 by Rockwell Automation. The motor driver produces 100 – 240 VAC with a

frequency range of 47 – 63 Hz and a 2000 Watt continuous power output. If the motors are

broken or do not comply with the motor drivers, the motors will be replaced. The motors will be

selected based on the rotation speed, torque, and dimensions of the mount. Motors will be

selected from the F-Series, Y-Series, 1326AB, or MP-Series Low-Inertia brushless servo motors

provided by Rockwell Automation [8].

Each motor will be controlled by the CompactLogix PAC system by Rockwell

Automation. The CompactLogix PAC system will be connected to a Windows based PC over a

network using Ethernet connection as shown in Figure 3. The PAC system is programmable

using the RSLogix 5000 programming language provided by Rockwell Automation.


Each motor will be removed from the robot and tested separately. As a safety measure,

the maximum range of rotation for each joint will be tested and programmed into the user

interface once the motor is mounted back into the robot. This procedure is to prevent twisting

and breaking of the robot. After all the motors have been mounted to the robot, forward

kinematics formulation will be programmed into the control system. Forward kinematic

principles are used to translate the joint angle configurations of the robot into the Cartesian

coordinate position of the end effectors in space. At this point, the application program will

move one motor at a time for the end effectors to reach its destination.

Next, a simple trajectory generation will be formulated based on the change or difference

between the initial and final joint angle configuration. The change in the joint angles is evenly

divided by the number of via points. For example, the change in an angle of a joint from its

initial state to its final state is 40 degrees, and 4 via points are desired to reach destination.

Figure 3. Block diagram of the components of the robot control system.

PC

PAC

Motor

Driver Motor

Driver

Motor

Driver

Motor

Driver

Motor

Driver

Motor

Driver

Motor Motor Motor Motor Motor Motor


Therefore the motor needs to rotate by 40 / (4+1) = 8 degrees per unit time. At this point, the

application will move all the motors simultaneously.

Once this phase of the project is accomplished and if time permits, inverse kinematic

functions will be formulated and added into the robot’s control interface. Inverse kinematics

allows translation from Cartesian coordinate to the joint angle configurations. If this

functionality is implemented, the user can input in Cartesian coordinates, i.e. the x, y, z

coordinates, and the angles of orientation of the wrist.

4.2. Codes and Standards

The design will use parts from Rockwell Automation. The connection between the motor

drivers and the motion controller will use the 2090-U3AE-D44xx cable connector by Rockwell

[10]. The motion controller is then connected to the PC using an Ethernet cable connection. The

programming language that will be used to program the motion controller is RSLogix 5000 by

Rockwell Automation.

4.3. Constraints, Alternatives, and Tradeoffs

The motor drivers need to be replaced with the Ultra 3000 motor drivers in order to

comply with the CompactLogix PAC system. The motors will have to be replaced if they are not

functioning properly or if they do not comply with the new motor drivers.

The user interface can be developed using LabView, Matlab, or Python. Programming in

any one of those languages will require an OPC library to communicate with the hardware. A

possible economic choice for an OPC library is the Open OPC [11]. However, this project will

utilize the RSLogix 5000 programming language, provided by Rockwell Automation. This

approach will eliminate driver issues from using other programming languages. In addition, the


RSLogix 5000 programming software includes Kinematics Robot Control Package, which is

capable of coordinating up to three axes [12].

In programming the robot, taking a forward kinematics approach is more preferable than

an inverse kinematics approach, because solving for a forward kinematics problem yields to a

single unique solution, while solving for an inverse kinematics problem yields to multiple

solutions making it more challenging. In addition, implementing inverse kinematics feature into

the robot requires a complex algorithm to determine the most efficient solution. Due to time

constraints, this project might not be able to implement the inverse kinematics feature into the

robot.

5. SCHEDULE, TASKS, AND MILESTONES

The design team will work as one entity towards each component of the project.

Successful completion of each phase of the project is important to move onto the next level and

hence all members will work together every step of the way. Table 3 displays the scheduled

tasks, duration, start dates, end dates, level of difficulty, and the main person responsible for the

task.


Table 3. Schedule, Tasks, and Milestones

January 12th

marks the commencement of the project and April 24th is the anticipated end

date. Appendix A shows the Gantt chart of the project.

6. PROJECT DEMONSTRATION

The demonstration of the project will take place in the Van Leer building Room 113, in

the last week of April. The goal of the demonstration is to show that the interface between each

component is established. The demonstration will be consisted of the following steps:

Desired position of each motor will be randomly generated and entered in the PC.

The motor in the arm robot will then move to the desired position one at a time.


Angle of each motor will be measured and compared to the input value. The goal is

achieved when the difference is within three degrees.

If time permits, the following steps will be performed:

Desired position of each motor will be randomly generated and entered in the PC. All

six motors in the arm robot will then move to the desired position simultaneously.

Angle of each motor will be measured and compared to the input value. This step is

accomplished if the difference is within three degrees for each motor.

Desired position of the end effectors will be randomly generated and entered in the

PC. The arm robot will then move the end effectors to the desired position. Location

and orientation of the end effectors will be measured and compared to the input value.

This step is accomplished if the error is within one cm and three degrees in any

Cartesian axis.

A spreadsheet of the desired positions will be loaded in the PC. The arm robot will

execute every instruction to form a smooth trajectory, such as drawing figure eight

with its end effectors.

During the demonstration, each of the four team members will have his own duty:

Enter numeric inputs provided by the PC or an audience and also demonstrate the PC

user interface.

Measure the angle of each motor in the robot or the location and orientation of the

end effectors and report the result.


Record all the results on the board and explain if the results meet specifications and

the reason for success and failure.

Explain concepts behind each step and prepare for an emergency stop in case of any

unexpected event.

7. MARKETING AND COST ANALYSIS

7.1 Marketing Analysis

The Unimation PUMA 500 robot has six degrees of freedom that allows it to reach any

point in space with any orientation. In 2004, about 5% to 15% of the industrial robots in injection

molding industry were six-axis articulated robots [12], leaving a big market for PUMA 500

robots to grow. However, since PUMA 500 series arm robot was manufactured in 1985 [7], it is

not equipped with modern technology such as a high speed microprocessor or zero-backlash

mechanism such as harmonic drive gearing [13]. Compared to the KUKA 5 sixx R850 [14], a

modern arm robot in the same class, the PUMA arm robot is inferior in many aspects such as

speed, repeatability, and payload, and is shown in Table 4.

Table 4. Comparison between PUMA 500 Robot and KUKA 5 sixx R850 Robot

Technical Specifications PUMA 500 KUKA 5 sixx R850

Axes 6 6

Repeatability ± 0.1 mm ± 0.03mm

Maximum Static Load 2.5 kg 5 kg

Maximum Speed 0.508 m/s 7.6 m/s

Reach 914 mm 814 mm


Although the PUMA 500 arm robot does not excel in comparison, it is capable of

completing any task where speed and accuracy is not critical.

Hand-held teach pendants are commonly used for programming arm robot in the current

market. Motoman NXC100 is an example of a hand-held teach pendant [15]. A PC-based

controller will replace the original hand-held teach pendant to control the PUMA arm robot.

According to [16], PC-based controllers have an advantage of reduced cost, improved

robustness, and open architecture platform. Six degrees of freedom and re-programming ability

allows the PUMA robot to handle different types of tasks with software updates, and thereby

reducing production cost and increasing its potential in the market.

7.2 Cost Analysis

Four major components required for the project are: motors in the arm robot, motor

drivers, PAC, and PC. The cost and status of each of the components is listed in Table 5.


Table 5. Cost and Status of Major Components

Item Description Part Number Typical

Cost Status Notes

Arm

Robot

[17]

Unimation

PUMA 500 N/A $5,000

Donated by

Dr. Harvey

Lipkin

Discontinued

Product; Used

robot is available

at auction sites

Motor

Drivers

(6) [18]

Ultra 3000

500W

2.5A/7.5A

2098-DSD-

005 $5,820

To be

Purchased

Sponsored by Dr.

Thomas E.

Michaels

Compact

Logix

[18]

EtherNet

Controller, 512

Kbyte memory,

16DI, 16DO,

24VDC

1769-L23E-

QB1B $1,816

Provided by

Rockwell

Automation

L2x Platform

PC [19]

Dell D600 P-M

1.4GHz/256MB

/20GB/XP

N/A $240

Provided by

Dr. Thomas

E. Michaels

and Phillip

Marks

Software

[18]

RSLogix 5000

Service Edition

9324-

RLD000ENE $571

Same as

Above

Total $13,447

As shown in Table 5, most hardware components are provided free of cost for the project.

he robot is donated by Dr. Harvey Lipkin, an Associate Professor in Automation and

Mechatronics. A laptop with RSlogix 5000 software is provided by Dr. Thomas E. Michaels and

Phillip Marks, an ECE graduate student. CompactLogix system is provided by Rockwell

Automation. The major components that are not present are the six Ultra 3000 motor drivers,

which cost $5,820 in total.

Dr. Thomas Michaels is the sponsor for this project and will cover the cost above the

$403 allowance for the Senior Design Project class. Real costs may vary as the functionality of

the motors is currently unknown, special harness may be required, and discounts from Rockwell

Automation may apply.


The other cost of the project would be the labor, which in this case is the work put in by

the group members. Table 6 projects the number of hours spent on a particular task for each

member.

Table 6. Estimated Labor Hours

Task J. Chao (Hr.) J. Tanis (Hr.) D. Lie (Hr.) F. Fernandes

(Hr.)

Class

Lecture 26 26 26 26

Reports 34 34 34 34

Website development 0 0 12 0

Project

Project Definition 32 32 29 32

Robot Inspection and Testing 48 48 45 48

Interface Components 26 26 23 26

Code Implementation 28 28 25 28

Total per Person 194 194 194 194

Total Hours 776

8. SUMMARY

The design team is continuing research on parts and components that need to be

purchased and implemented. Gathering information on Rockwell ControlLogix PAC system,

RSLogix 5000 software, motor drives, I/O module cards, and MP-Series Low-Inertia brushless

servo motors provided by Rockwell Automation [8]. The group has met with Dr. Thomas E.

Michaels who has stated the goals and objectives, and provided useful insight for a successful

working Unimation PUMA 500 robot controlled by a Rockwell Automation PLC. Next two

weeks will be dedicated in disassembling the motors from the robot, testing each motor

individually, repairing if possible, and replacing if necessary. Implementation will then take

place once all the parts have arrived.


9. REFERENCES

[1] J.M. Pethokoukis. (2004, Mar. 7). Industrial robots are reshaping manufacturing. U.S.

News [Online]. Available:

http://www.usnews.com/usnews/biztech/articles/040315/15eerobots.htm

[2] ATSI. (2008). Articulating Arm Robot [Online]. Available:

http://www.atsi.cc/articulating-arm-robot.htm

[3] ATSI. (2008). Robot Basics [Online]. Available: http://www.atsi.cc/robotbasics.htm

[4] RobotWorx. (2009). Industrial Arc Welding Robot Application [Online]. Available:

http://www.robots4welding.com/applications.php?app=arc+welding

[5] Rockwell Automation. (2007). Rockwell Automation Incorporates More Than 30 Product

Enhancements into Latest Version of Rockwell Software RSLogix 5000 Programming

Software [Online]. Available: http://phx.corporate-

ir.net/phoenix.zhtml?c=196186&p=irol-newsArticle&ID=957142&highlight=

[6] W. Bihr and F. Degrange. (1999). Interfacing of a Force/Torque sensor on a PUMA 500

robot. Georgia Inst. of Technology. Atlanta, GA. [Online]. Available:

http://helix.gatech.edu/Students/SiouxWill/project.html

[7] Unimation (1985, March). PUMA Mark II Robot 500 Series Equipment Manual for VAL

II and VAL PLUS Operating System.

http://www.usnews.com/usnews/biztech/articles/040315/15eerobots.htm

http://www.atsi.cc/articulating-arm-robot.htm

http://www.atsi.cc/robotbasics.htm

http://www.robots4welding.com/applications.php?app=arc+welding

http://phx.corporate-ir.net/phoenix.zhtml?c=196186&p=irol-newsArticle&ID=957142&highlight

http://phx.corporate-ir.net/phoenix.zhtml?c=196186&p=irol-newsArticle&ID=957142&highlight

http://helix.gatech.edu/Students/SiouxWill/project.html


[8] Rockwell Automation (2004, September). Ultra 3000 Digital Servo Drives [Online].

Available:

http://literature.rockwellautomation.com/idc/groups/literature/documents/br/2098-

br002_-en-p.pdf

[9] Rockwell Automation (2008, July). CompactLogix Controllers Selection Guide [Online].

Available:

http://literature.rockwellautomation.com/idc/groups/literature/documents/sg/1769-

sg001_-en-p.pdf

[10] Rockwell Automation (2004, April). Ultra 3000 Digital Servo Drives Installation Manual

[Online]. Available:

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/2098-in003_-

en-p.pdf

[11] SourceForge.net. OpenOPC for Python [Online]. Available:

http://openopc.sourceforge.net/

[12] M. Knights, Six axis robot: where they fit in injection molding, Plastics Technology

[Online Article]. October 1, 2004. Available:

http://goliath.ecnext.com/coms2/summary_0199-1325378_ITM

[13] A. Lauletta (2006, April), The Basics of Harmonic Drive Gearing, Power Transmission

Engineering, [Magazine]. pp.32.

http://literature.rockwellautomation.com/idc/groups/literature/documents/br/2098-br002_-en-p.pdf

http://literature.rockwellautomation.com/idc/groups/literature/documents/br/2098-br002_-en-p.pdf

http://literature.rockwellautomation.com/idc/groups/literature/documents/sg/1769-sg001_-en-p.pdf

http://literature.rockwellautomation.com/idc/groups/literature/documents/sg/1769-sg001_-en-p.pdf

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/2098-in003_-en-p.pdf

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/2098-in003_-en-p.pdf

http://openopc.sourceforge.net/


[14] KUKA Roboter GmbH, “KR 5 sixx R850,” [Company Website], Available:

http://www.kuka-

robotics.com/usa/en/products/industrial_robots/small_robots/kr5_sixx_r850/start.htm

[15] RobotWorx, “Motoman NX100 Teach Pendant,” [Company Website], Available:

http://www.robots.com/motoman.php?controller=nx100

[16] M. Faroog, “Implementation of a new PC-based Controller for a PUMA robot,” Journal

of Zhejiang University-Science A,” vol. 8, no.12, pp. 1962-1970, Nov. 2007.

[17] Ebay Inc., ”Staubli PUMA 500 Robotic Robot Arm 1621 hrs CS4 Panel,” [Company

Website], Item number: 270328501673, Available: http://cgi.ebay.com/STAUBLI-

PUMA-500-ROBOTIC-robot-ARM

[18] Rockwell Automation Shop, [Company Website], Available:

http://shop.rockwellautomation.com/RA/index.jsp?scrnCurrentStore=RA

[19] Ginstar Computer Inc., “Dell D600 P-M 1.4GHz/256MB/20GB w/CD-ROM/XP,”

[Company Website], Available: http://www.ginstar.com/productList.aspx?category=41


APPENDIX A – PROJECT GANTT CHART

See next page for project Gantt chart.


Documents

Interfacing a PUMA 500 Robot with a PC-based Controller · Yellow PUMA (ECE4007L01) iii EXECUTIVE SUMMARY The Unimation PUMA (Programmable Universal Machine for Assembly, or Programmable