Table of Contents INTRODUCTION... 3 REQUIREMENTS... 3 HAND... 3 CONTROL GLOVE... 3 TRANSMITTER AND RECEIVER... 3 PROGRAM... 4 BLOCK DIAGRAM... 4 SPECIFICATIONS... 4 DESIGN APPROACH... 5 THE CONTROL GLOVE... 6 THE PROGRAM... 6 MANIFOLD AND SOLENOID OPERATION... 6 THE MECHANICAL HAND... 6 PRODUCT COST ANALYSIS... 7 STATEMENT OF WORK... 8 WBS TABLE... 10 WORK PACKAGES... 11 SCHEDULES... 12 GANTT... 12 PERT... 12 PROBABILITY ANALYSIS... 14 PROJECT COST ANALYSIS... 15 1
WORK REVIEW PLAN... 16 TEST PLAN... 16 CONTROL GLOVE... 16 PROGRAM... 17 MECHANICAL HAND... 18 AREAS OF CONCERNS WITH CONTINGENCY... 18 2
Introduction A mechanical system consisting of a robotic hand will be built, starting on September 23 rd, 2002. Ernesto Ayon, Eric Hamer, Ronald Huereca and Carmody Rauch will build the project. The mechanical hand will be built with metal and will be air powered. The estimated time to complete this project is 12.6 weeks, which should end the project on January 17 th, 2002. The project will consist of a mechanical hand that is powered by pneumatic components. The pneumatic components will be controlled electronically via a Motorola HC11. The HC11 will take inputs wirelessly from a control glove that a user will wear. The mechanical hand will base its movement on the control glove. The estimated labor hours are 339 hours, which should put the cost of labor at $6,780 dollars. The completed project, including labor, materials, and overhead is $23,207.60 dollars. The product cost for one unit (Bulk 1000) is $8,861.84. Requirements Listed below are the requirements for the overall system of the mechanical hand. The requirements cover the hand, control glove, manifold, and the program. Hand Metal hand will have an opposable thumb, and will be larger and stronger than a human hand. Mimic grasping motion. Movement of fingers will be by pneumatic cylinders. Elbow and wrist action will provide horizontal and vertical motion. Control Glove Senses motion of fingers. Converts raw data to transmittable data. Houses controls for elbow and wrist. Transmitter and Receiver Will transmit data quickly and simultaneously. 3
Will have short-range transmitter. Program Able to receiver inputs and control outputs. Try to attain simultaneous control glove-hand movement. Use feedback to correct errors. Block Diagram Shown below is the block diagram for our project. A glove worn by a user sends data to a micro controller. A pneumatic manifold receives this data and outputs it to the air compressor as well as the mechanical hand. User interface: initiates microcontroller protocol Glove: worn by user, senses hand movement, broadcasts data to microcontroller Microcontroller: accept data from glove, determines and outputs control signals Manifold: receives control signals from microcontroller, controls airflow to robotic hand Hand: pneumatically controlled mechanic hand, mimics glove movement Air compressor: supplies air for pneumatic system at 60 psi Specifications Listed below are the specifications for the completed mechanical hand. Specifications have been included for the standalone mechanical hand, as well as the control glove, transmitter & receiver, and the HC11 program. 4
Mechanical Hand: Will be approximately 2 feet in length. Will be able to lift 20 pounds. Each cylinder will have 1 inch of motion -> Each knuckle will have 90 s of movement. Elbow will have vertical motion of 0-1.5 feet. Elbow will have horizontal motion of 8 inches either way. Wrist will rotate hand. Control Glove: Knuckle movement will be sensed using brake cable attached to potentiometers. When a trigger voltage is reached, the movement will be translated to the hand. Each knuckle will have it s own cable and potentiometer. Circuit board will contain circuit that converts raw data to transmittable data. Circuit board will also have switches/dials that controls the position of the elbow and wrist. Will be battery operated. Transmitter and Receiver: Short-range transmitter of 0-10 feet. Nine transmitters, one for each knuckle. Program: HC11 will receive 9 transmitted signals. Program will decide which knuckle moved and then output to corresponding solenoid. Input to output time will be no longer than 0.5 seconds. Design Approach An overview of this project includes designing a mechanical hand that is to be pneumatically powered so that it mimics the movement of a user's hand. The mechanical hand will be connected to a microprocessor, specifically Motorola's 68HC11, which will wirelessly receive inputs from the controller's glove and send the corresponding data to the manifold controlling the pneumatic cylinders on the mechanical 5
hand. The following is a detailed description of all the subsystems, their design, construction, and final integration. The Control Glove The control glove worn by the user will completely cover the user's hand and be made of a flexible, yet sturdy material such as neoprene. In order to "sense" the position of the fingers of the user's hand, a circuit containing pressure and/or position transducers will be designed and attached to the glove upon completion of its construction. One method of sensing the position of the user's fingers will be to attach cables from the ends of the corresponding pressure and/or position transducers. The outputs of this circuit will be sent to an Analog to Digital circuit, which will convert the information containing the positions of the fingers into binary words. These binary words will then be sent to a transmitting circuit so that the information can wirelessly reach the microprocessor. All three of the circuits mentioned above will initially be constructed and tested on breadboards, then reduced to their smallest possible size so that a permanent circuit board can be constructed and attached to the control glove, giving the user as much comfort as possible. The Program The data transmitted to the microprocessor will be received by a receiving circuit connected to Motorola's 68HC11. These binary words will be latched into one of several digital registers so that the program controlling the microprocessor can periodically scan the information. This program will be designed to control at least nine pneumatic cylinders; with each cylinder being able to achieve at least one opened and closed position. The program will decode the binary words to determine the position of the user's hand in the control glove and use the corresponding data to control several solenoid driving circuits. Manifold and Solenoid Operation The solenoid driving circuits will be controlling at least eighteen of the twenty available solenoids in the pneumatic manifold. Each cylinder has two input/output ports in which the air moves in and out of them. It requires two solenoids to control one cylinder since the movement of each solenoid allows air to flow into or out of its corresponding port. The solenoids controlling the airflow within the manifold require at least 12 volts and 150 mamps to activate. The Mechanical Hand The design and construction of the mechanical hand will consist of several steps and prototypes before the final product can be achieved. The mechanical hand will be made to be proportional to the appearance of the human hand, yet it will be much larger and stronger. Two pneumatic cylinders will control each finger, excluding the thumb. 6
One cylinder will be behind the base of the finger and will be responsible for providing a rotation of about 90 degrees around the "knuckle" of the hand. The base of the second cylinder will be at the end of the first cylinder and will be responsible for also providing a rotation of about 90 degrees, except, this rotation will bend each finger in half producing a life-like effect of the human hand. The thumb will be controlled by only one cylinder and like the all of the fingers, will have a curvature at the tip to provide the mechanical hand with the ability to grip objects. The first prototype will be made of cardboard and will be very primitive compared to the final product. Its purpose is to provide a model that can be used determine the placement of the cylinders in order to achieve the desired rotation, as well as provide a model that can easily be altered so that the shape and size of the final product can be determined. After the redesign and development is complete, a second prototype will be made of wood and will be an exact replica of the final product. This model will be used to test the design of the mechanical hand in conjunction with the cylinders, manifold, and microprocessor. Any necessary adjustments will be made before the final product is constructed. The final product will be made of a lightweight aluminum alloy in order to provide the mechanical hand with additional strength, without drastically increasing its weight and/or size. Once the final product is complete, all of the subsystems will be integrated, tested, and if necessary, debugged. Product Cost Analysis For 1/1000 units: $8,861.84 Total Materials per 1/1000 units: $858.40 All of the materials for this project will go down in price when bought in quantity. The final price for one unit for orders of 1000 units is 40% of the single unit price ($858.40). Total Labor Cost: $2,550.00 Since technicians will be used instead of engineers, the labor cost will go down when building 1000 units. Instead of an engineers $20 an hour, a technician would only receive $15 an hour. Since the design is already available, fewer workers will be needed to construct the units. 7
The total labor cost will be: 2 technicians @ $15 per hour x 85 = $2,550.00 Overhead for 1000 units: $5,453.44 Materials + Labor = $3,408.40 x 160% = $5,453.44 Total Price per unit for 1000 units: $8,861.84 Materials + Labor + Overhead: $8,861.84 Statement of Work Our work has been broken down into different subsections, with each team member responsible for a certain part of the project. Carmody Rauch is in charge of the control glove, Eric Hamer and Ernesto Ayon are in charge of the mechanical hand, and Ronald Huereca is in charge of the program. The tasks to be completed can be observed in the attached Work Breakdown Structure Tree & Table. 8
1.1 Sensory 1.11 Brake Line and Sheath 1.12 Linear POT Connection 1 Control Glove 1.2 Wireless Portion 1.21 Transmitter 1.22 A to D Conv. 1.3 Glove Construction 1.31 Plexi-Glass Box 1.32 Circuit Board Pneumatically Powered Mechanical Hand 2 Mechanical Hand Program 3 2.1 Prototype Actual Hand Manifold Designing Wood Cutting Construction Testing 2.11 2.12 2.13 2.14 2.15 Re-Designing Metal Cutting Assembly Testing 2.2 2.21 2.22 2.23 2.3 2.31 Solenoid Driver Setup 2.32 Air Compressor Power Amplification 2.33 Pressure Testing 2.34 Timer Testing 3.1 Program Construction 3.12 Flow Chart (Brainstorming) 3.13 Writing the Program 3.14 Debugging Testing 3.2 3.21 Program with Glove 3.22 Program with Manifold 3.23 Program with Mechanical Hand Project Work Breakdown Structure 9
WBS Table Task # Task Name Team Member Responsible Prerequisites Ronald Huereca Ernie Ayon Eric Hamer Carmody Rauch 1 Control Glove X X 1.1 Sensory X 1.11 Brake Line & X Sheath 1.12 Linear POT X 1.31 Connection 1.2 Wireless Portion X X 1.1 1.21 Transmitter X 1.22 Analog to X Digital Conversion 1.3 Glove Construction X 1.31 Plexi-Glass Box X X 1.32 Circuit Board X 1.31 2 Mechanical X X X Hand 2.1 Prototype X X 2.11 Designing X X 2.12 Wood Cutting X X 2.13 Construction X X 2.12 2.14 Testing X X 2.13 2.15 Re-Designing X X 2.14 2.2 Actual Hand X X 2.1 2.21 Metal Cutting X X 2.22 Assembly X X 2.21 10
2.23 Testing X X 2.22 2.3 Manifold X X X 2.31 Solenoid Driver Setup X 2.32 Air Compressor X 2.31 Power 2.33 Pressure Testing X X X 2.32 2.34 Timer Testing X X X 2.33 3 Program X X X X 3.1 Program X Construction 3.12 Flow Charting X 3.13 Writing the X 3.12 Program 3.14 Debugging X 3.13 3.2 Testing X 3.1 3.21 Program with Glove 3.22 Program with Manifold 3.23 Program with Mechanical Hand X X 1 X 2.3 X X X 2 Work Packages Shown on the proceeding pages are the work packages for the minor blocks on the WBS Tree. Calculations, such as a, m, and b are in days. Those calculations are recalculated in weeks for the PERT chart. Please refer to the Work Packages PDF for the complete work packages. 11
Gantt Schedules The overall schedule for the project is shown below. The project has been broken down into three main projects. The first main project is the control program that is to be written for the Motorola HC11. This task will be completed when the all other work is done because of its need to be tested with the complete system working. The second subproject is the mechanical hand that is the end goal of the full project. The mechanical hand takes the longest because it is the most difficult part of the project physically. Much design and labor must be contributed in order for the hand to perform as expected. The third part is the control glove that is a required part of the project. The control glove is the only way the movements of the user can be measured and communicated to the HC11. The project is started on September 23 rd, 2002 and is expected to wrap up January 17 th, 2002. Please open the additional Gantt.pdf in order to view the Gantt chart. PERT Shown below is the PERT chart for the project. The critical path is highlighted. The project is estimated to take 12.6 Weeks. 12
C Mechanical Hand M Research Control Glove Research Pneumatic Components 1 D 0.5 1 Program Brainstorming A Set up Wireless Transmitter R Test Transmitter on circuit board Build & Test Linear Potentiometer Circuitry P Connect A to D Converter F Design and build Hand 1 st Prototype Test A to D on circuit board Q N 2 O Build Solenoid Driver Circuit E B Writing the Program Debugging Test Reaction time of cylinders H Design & build 2 nd Hand Prototype Draw Blueprints for metal cutting G 3 1 J 3 K 1 2 2 Have metal cut Integrate cylinders with mechanical hand Integrate with Program and Mechanical Hand S L Build final Mechanical Hand 0.1 I 2 1 1 Integrate with Program T 1 0.1 0.1 0.1 1 2 1 Test Control Glove, Mechanical Ha nd, and Program Together U Letters Correspond to Each Activity = Critical Path Numbers Correspond to Weeks D, F, G, J, K, L, T, U Total Time = 12.6 Weeks 13
Probability Analysis a m b te V Program Brainstorming 0.5 1 2 1 0.0625 Writing Program 0.5 1 2 1 0.0625 Debugging 0.5 1 2 1 0.0625 Research Pneumatics 0.25 0.5 1 0.5 0.015625 Build Solenoid Drivers 0.05 0.1 0.2 0.1 0.000625 Test Reaction Time 0.05 0.1 0.2 0.1 0.000625 Integrate Cylinders with Hand 0.05 0.1 0.2 0.1 0.000625 Design 1st Prototype 0.05 0.1 0.2 0.1 0.000625 Design 2nd Prototype 1.5 3 4 3 0.173611 Draw Blueprints 0.5 1 2 1 0.0625 Have metal cut 1.5 3 4 3 0.173611 Build Final Hand 1 2 3 2 0.111111 Integrate with Program 0.5 1 2 1 0.0625 Research Control Glove 0.5 1 2 1 0.0625 Build and Test POTS 1 2 3 2 0.111111 Connect A to D Converter 0.5 1 2 1 0.0625 Set up Xmitter 1 2 3 2 0.111111 Test Xmitter on board 1 2 3 2 0.111111 Test A to D 0.5 1 2 1 0.0625 Integrate with Hand 0.5 1 2 1 0.0625 Test Final 1 2 3 2 0.111111 Vp(CP) = 0.363472 Te(CP) = 12.6 Ts = 14.5 Weeks Z = 3.15 Probability of completion is: 99.99 % 14
Project Cost Analysis For One Unit: $23,207.60 Materials Price Air Regulator $15 Air Compresssor $80 Slide Pots (9) $20 Pneumatic Cylinders (11) $33 Cylinder Fittings $245 10 Valve Manifold $1,300 Metal Work $50 Gloves $20 Air Tubing $10 Circuit Board $25 Reservoir Tank $30 Manifold Fittings $90 ADC IC $5 Solenoid Driver (6) $30 Wood & Woodwork $50 Screws & Bolts $13 Transmitter $50 Receiver $50 Brake Cable $30 Total Labor Cost per unit: $6,780 Total hours worked is 339 hours times $20 an hour = $6,780 Overhead Cost per unit: $14,281.60 Materials + Labor = 8,926 x 160% = $14,281.60 Total Cost per unit: $23,207.60 15
Materials + Labor + Overhead = $23,207.60 Work Review Plan Work and progress of the project will be reviewed on a regular basis. Ronald Huereca (Project Manager) and Ernesto Ayon (Meeting Facilitator) will determine what needs to be worked on during the scheduled project lab in the eighth semester. Each week, the team will meet with the senior advisor to determine progress on the project. In addition, every Thursday the team will meet to discuss miscellaneous project issues. This meeting will be at least ten minutes, but can carry on for up to an hour. If an emergency meeting needs to be conducted, the project manager will let the team know at least a day in advance. The purpose of an emergency meeting is if something drastic has happened to the project, or if something specific needs to be done right away. Test Plan The purpose of this test plan is to make sure the project meets the requirements, as well as fulfills the overall purpose of the project. The tests below will ensure that all parts of the mechanical hand system work seamlessly together. Control Glove Linear Pot Connection Flex each finger individually and make sure the linear potentiometer extends the same length for each finger. Test the voltage with a voltmeter to ensure the voltage ranges from 0 5 volts so the input is adequate enough to go to the analog to digital converter. Analog to Digital Converter Test the input to ensure the voltage given is within 0 5 Volts. Test the output to ensure that 19.6mV step is achieved. Ensure that the correct binary word is reaching the transmitter on the control glove. Transmitter Test an input of a binary word and transmit and make sure the binary word reaches its destination intact. Note the amount of errors received and make sure this is 16
adequate enough for the HC11 s input. If the error is too great, a transmitter may not be feasible and standard wire will have to be implemented in place of the transmitter. Circuit Board Test the linear potentiometer, analog to digital converter, and transmitter to ensure that the correct data is being collected. Check the solder connections for any missing grounds and power. If the circuit board is not adequate, a standard breadboard may have to be used. Program Program with Control Glove Test the program and make sure the program is receiving and storing the nine data entries from the control glove. Make sure the nine entries are being verified and outputted correctly. Make sure the program fits within the specified 512 bytes of memory on the 68HC11. If more memory is needed, the EEPROM may be used, or the board will have to be set up in expanded mode. Be sure the onboard analog to digital converter is working correctly and ensure that the receiver input is true to the transmitted data on the control glove. Program with Manifold This test ensures that the program is outputting the correct data to the correct solenoid. The wearer of the control glove will flex each finger one at a time to ensure that the 68HC11 is outputting the data to the assigned solenoid for each finger. If an incorrect solenoid is activated, the program will have to be debugged. If each solenoid lights correctly, the program will then test the control glove for fingers being flexed simultaneously. The worst-case scenario is that only one finger may be flexed at one time. Program with Mechanical Hand The wearer of the control glove will flex each finger one at a time to ensure that the 68HC11 is outputting the correct data to the solenoid. If this test is passed, the manifold will then be hooked up to the mechanical hand to ensure that each cylinder is being given the correct amount of air. If the air is not outputted correctly, the timing mechanism in the 68HC11 will have to be modified. If each cylinder works correctly, the whole mechanical hand will be tested to ensure simultaneous motion. If the HC11 has passed all tests and the cylinders do not behave as planned, the mechanical hand will have to be redesigned to fit the application. 17
Mechanical Hand Air Compressor Ensure that the power supply is giving the required 17 Amps and 12 Volts for correct operation. Make sure that industrial leads are being used in order to take the amount of power dissipated by the air compressor. Test the PSI rating to make sure the required 60-PSI is going into the manifold. If the manifold is receiving inadequate PSI, the air regulator will have to be adjusted. Solenoid Drivers Test the solenoid drivers to ensure that the 145mA at 12 volts is being applied to each solenoid in the manifold. If the chip is not delivering the appropriate ratings, ensure proper connections. Replace the chip if the requirements are still not met. Timer Testing Test the cylinders with bursts of air to achieve multiple positions for each cylinder. If the cylinder cannot achieve multiple positions, adjust the timing to a minimum on the HC11 s output and determine if this solves the problem. The worst-case scenario would be there is only one position per cylinder. Mechanical Hand Prototype Test the prototype to ensure that if a cylinder s piston is flexed 1 inch, that the degree of movement is no less than 90 degrees. If the cylinder s position is less than 90 degrees, the prototype will have to be redesigned. Test the prototype to ensure that if all fingers move simultaneously, that none of the fingers will interlock or have impact. If any of the fingers interlock or have impact, the prototype will have to be redesigned. Mechanical Hand Final Test the hand to ensure that if a cylinder s piston is flexed 1 inch, that the degree of movement is no less than 90 degrees. Test the hand to ensure that if all fingers move simultaneously, that none of the fingers will interlock or have impact. If any of the fingers interlock or have impact, the hand will have to be adjusted to fit the prototype. Areas of Concerns with Contingency area. This section will highlight the areas of concern with a contingency plan for each Time What if we run out of time for the project? 18
If the project cannot be completed on time, several tasks will be removed. The critical tasks are the mechanical hand, control glove, and program. If time doesn t permit, the elbow and wrist can be removed from the mechanical hand. Also, if there isn t enough time to set up the wireless transmitter, standard wire inputs will be used instead. This cut in components should be a sufficient decrease on the time burden facing the project. Funds What if we run out of funds for the project? The first contingency would be to ask our relatives for the additional funding. If the relatives are unable to provide, a possible bank loan will be used. If a bank loan is not feasible, tasks will have to be cut from the project. Such tasks would be removing the elbow and wrist, which would cost the most money to implement. Additionally, if wireless is not feasible with the budget, the wireless capabilities of the control glove can be cut down to just standard wire. Hand What if we are unable to make the cylinders do two positions? If the cylinders are unable to do two positions (up and down), the manifold will have to be troubleshooted thoroughly. If all else fails, the manifold will be brought back to the manufacturer for fixing. If time does not permit returning the manifold, the project will be unable to complete according to the requirements and specifications. What if the hand can't stand the pressure of the cylinders? The cylinders are very lightweight and this does not seem to be a problem at the moment. However, if the hand cannot stand the pressure of the cylinders, a tougher metal will have to be used. If time does not permit, the hand will have to work with fewer cylinders, which would modify the program and control glove. The worst-case scenario is that only one finger (made of cylinders) will be used. What if we can't work out the wrist and elbow? The wrist and elbow are one of the beneficial components of the mechanical hand, making the hand seem life-like. However, if the elbow and wrist cannot be implemented, most of the requirements can still be met. The elbow and wrist are not a crucial component of the mechanical hand design, so disregarding them in the project would be feasible. 19
What if the hand crushes itself? Stronger material must be used. If time does not permit, the hand will have to work with fewer cylinders, which would modify the program and control glove. The worst-case scenario is that only one finger (made of cylinders) will be used. Program What if the program is too slow? If the program is too slow, two HC11 s may have to be used. If using two HC11 boards is not feasible, the mechanical hand will have to be brought down to fewer cylinders. What if we can't get the program debugged? If the program cannot be debugged, we will meet with Professor Plotnick and have him go over the program with us. However, if the program still cannot work, the project will be unable to complete. What if the HC11 can't handle our project? If the HC11 cannot handle the project, another microprocessor will be needed. However, this calls for learning a new assembly language and chip set. Considerable time will be needed for this task. According to the PERT chart, the program has the most slack. However, if the time does not permit, the project will have to be scaled down so that the HC11 can handle all the inputs and outputs. Glove What if the motion sensors won't stay on the glove? It is critical the motion sensors stay on the glove, however, if there isn t enough room on the glove for the motion sensors, they may be mounted on a circuit board near the glove. The glove, however, will have to remain stationary and the motion sensors setup so that they interact seamlessly with the glove. What if the glove's power supply doesn't last long enough? We will keep adequate amounts of batteries around to ensure the power does not interrupt while in operation. However, if the battery operation isn t feasible, the lab s power supply must be used. 20
What if the transmitter's quit working? Standard wire will have to be used to send inputs to the HC11. What if the ADC's stop working? Standard wire will have to be used to send inputs to the HC11. Pneumatics What if the manifold breaks? The manifold will be sent to the manufacturer for repairs. However, if time doesn t permit, the project will ultimately be unsuccessful. What if tubes start getting plugged? Troubleshooting into the problem will begin. If the manifold is plugging the tubes, the manifold will be sent in for repairs. If the tubes are just building up particles, the tubes will be replaced. 21