Feeding system for disabled report

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Feeding system for disabled report

  1. 1. Feeding System for Disabled Submitted by Group 2 Mayank Awasthi 2006033 Md Sadhiq 2006034 Anand Kumar 2006076 Under the supervision of Mr. Awadesh Kumar Singh Design Project (MN-302) Instructors: Prof. Amit Ray Dr. Puneet Tandon Dr. M.K. Roy Pandit Dwaraka Prasad Mishra IndianInstitute of Information Technology Design and Manufacturing, Jabalpur i
  2. 2. DEDICATION To Our Project Guide, Faculty members,Workshop, Lab Assistants & SeniorsFor Letting Us to Fulfill Our Dreams ii
  3. 3. ACKNOWLEDGEMENTFirst of all, we would like to express our sincere thanks to our supervisor Mr.Awadesh Kumar Singh for his intellectual guidance, continuous interest,generous support, infinite patience, and constant encouragement throughout thisproject work. He has devoted his valuable time to discuss this project, hisexpertise and broad knowledge in Engineering Design played a major role in therealization of this work. We appreciate Mr. Awadesh Kumar Singh for hisconfidence boosting start up to our project work and encouragement in creativeendeavors.We especially appreciate the company of our classmates, seniors, workshop &lab assistants and who have made useful to this work by way of discussions andsuggestions from time to time. Group II Mayank Awasthi (2006033) Md Sadhiq (2006034) Anand Kumar (2006076) iii
  4. 4. ABSTRACTPeople with disabilities constitute a large percentage of the population, includingthose who have difficulty using their hands and arms to control and manipulatetheir environment. In order to live their daily lives, they must be under constantsupervision. Often, this requirement is not met because such care is hard to finddue to lack of assistance or for financial reasons. If a feeding system could bedesigned and manufactured for these people, the need for constant supervisioncould be reduced drastically. The feeding system could assist them in feedingthemselves. It would rebuild confidence and self-esteem lost in the depth ofillness. iv
  5. 5. CONTENTS I. Objective ……………….................1 II. Research …………………………...2 III. Technical Details ……………………4 IV. Fabrication Process ………………...8 V. Working …………………………… 12 VI. Costing ……………………………….13 VII. Conclusion …………………………...16 VIII. References …………………………17 IX. Appendix ……………………………. i. Microcontroller Program ii. Product Photos v
  6. 6. ObjectiveThe aim of this project is to design a lightweight, easy to use, and low costrobotic feeding arm, which would act as an extension for the affected people toregain their independence from disease. The functional requirement of the deviceis that it should allow the user to manipulate a feeding utensil and to bring theliquid to the mouth.We have divided this project in two phases:Phase I: In last semester we did the CAD modeling & simulation of our design &also completed a working prototype of our design.Phase II: In this semester we have done the fabrication and microcontrollerprogramming for servo controlled precise movement of the arm. vi
  7. 7. ResearchThere are basically two robotic arms out on the market currently, the HelpingHand and the MANUS. The Helping Hand was produced by Kinetic RehabInstruments (KRI), they have since gone out of business. It is controlled by ajoystick interface and has four degrees of freedom not including the gripper. TheMANUS is produced by a company called Exact Dynamics. It is controlled by asixteen key, keypad interface and has seven degrees of freedom.The marketing difficulties are the same for both of these devices. Those whohave heard about robotic devices aren’t convinced about the benefits and theusability of the devices. Therefore potential users of a robotic arm are findingalternative solutions. For example: smart homes, environmental control systemsand human assistants. In addition to high cost, another problem is that mostpeople have never heard of rehabilitation robotics. A better market strategy isnecessary to convince potential users to choose robotics as a solution.Requirements:  The manipulator should be robust, light weight, modular, easy-to-operate and safe.  It should be cost effective.  The arm’s workspace should be similar to the arm of an average man having aesthetic look. vii
  8. 8. Technical Details:The basic key elements of the configuration are:  Degree of freedom  Linkages  Transmission  Actuation HS-322HD servo motors  ATMEL 89S52 Microcontroller  User Interface(through Computer)Servo Motors:Servo motors are used in closed loop control systems in which work is the controlvariable. The digital servo motor controller directs operation of the servo motor bysending velocity command signals to the amplifier, which drives the servo motor.An integral feedback device (resolver) or devices (encoder and tachometer) areeither incorporated within the servo motor or are remotely mounted, often on theload itself. These provide the servo motors position and velocity feedback thatthe controller compares to its programmed motion profile and uses to alter itsvelocity signal. Servo motors feature a motion profile, which is a set ofinstructions programmed into the controller that defines the servo motoroperation in terms of time, position, and velocity. The ability of the servo motor toadjust to differences between the motion profile and feedback signals dependsgreatly upon the type of controls and servo motors used.Principle strengths of Servo Motor:1. High performance2. Small size3. Wide variety of components4. High speeds available with specialized controlsPrinciple weaknesses:1. Slightly higher cost2. High performance limited by controls3. High speed torque limited by commutator or electronics viii
  9. 9. Functioning of servo Motor: Block Diagram of servo controlHS-322HD Servo Motors Specifications:This servo comes with mounting hardware, mounting grommets, and 4 servohorns. The HS-322HD servo has heavy duty gears for smoother operation andlonger life when compared to normal servos. This servo has a Hitech/JRconnector which mates directly with a 0.1" 3-pin header. The servo spline has 24teeth and mates with Hitec compatible accessories. Specifications Voltage Operating Speed Output Torque Weight Range 0.19sec/60 degrees at 3kg.cm (41.6oz.in) at 43.0g4.8V - 6V 4.8V 4.8V (1.51oz)Wire Color MeaningOn all Hitec servos the Black wire is ground, the Red wire (center wire) ispower, and the yellow (third) wire is signal. ix
  10. 10. How to communicate the angle at which the servo should turnThe control wire is used to communicate the angle. The angle is determined bythe duration of a pulse that is applied to the control wire. This is called PulseCoded Modulation. The servo expects to see a pulse every 20 milliseconds (.02seconds). The length of the pulse will determine how far the motor turns. A 1.5millisecond pulse, for example, will make the motor turn to the 90 degree position(often called the neutral position). If the pulse is shorter than 1.5 ms, then themotor will turn the shaft to closer to 0 degress. If the pulse is longer than 1.5ms,the shaft turns closer to 180 degress.As seen in the picture, the duration of the pulse dictates the angle of the outputshaft (shown as the green circle with the arrow).ATMEL 89S52 8-bit Microcontroller:The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with8Kbytes of in-system programmable Flash memory. The on-chip Flash allows theprogram memory to be reprogrammed in-system or by a conventional nonvolatilememory programmer.By combining a versatile 8-bit CPU with in-system programmable Flash ona monolithic chip, the Atmel AT89S52 is a powerful microcontroller whichprovides ahighly-flexible and cost-effective solution to many embedded control applications. x
  11. 11. The AT89S52 provides the following standard features: 8K bytes of Flash, 256bytesof RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bittimer/counters, asix-vector two-level interrupt architecture, a full duplex serial port, on-chiposcillator,and clock circuitry.PIN Configuration Pin configuration of ATMEL 89S52 xi
  12. 12. Dimension:Base board 18’’*12’’*2’’Base arm 2.5’’*2.5’’*6’’Shoulder Link 11’’Spoon Length 5’’Fabrication ProcessFabrication process involved two modules  Mechanical design  Circuit design  User InterfaceMechanical Design:Base:  The base is a key point in our design of feeding system. In the base we have used a HS-322HD servo motor which is used to rotate the whole system.  The whole arm is connected to the spindle of the base motor using ball bearings to minimize the load on the spindle and for the smooth rotation of the arm. Moreover it would minimize the vibrations of the system during rotation. xii
  13. 13. Shoulder Link:  The shoulder assembly consists of a link which is controlled by a HS- 322HD Servo Motor.  This shoulder link has another servo motor connected to one of the ends to control the spoon motion. Due the weight of the servo motor shoulder is unable to with stand in its position. So a counter balancing mechanism is used to minimize the gravity effect.Feeding Spoon:  The feeding spoon is controlled by a HS-322HD servo motor which is fixed at the end of the shoulder link.  This spoon is used to lift the food items (mainly liquids) from the bowl which is placed on the table at a fixed location. xiii
  14. 14. Circuit Design:In our circuit design we have used two ATMEL 89S52 microcontrollers to controlthe three servo motors. One microcontroller acts as a master and other one asthe slave.The master is used to control the motion of base and the spoon. And the slave isused to control the shoulder link. These two microcontrollers are working on theprinciple of parallel processing. It use of more than one CPU or processor ormicrocontrollers to execute a program or multiple programs. Ideally, parallelprocessing makes programs run faster because there are more engines (CPUsor cores) running it.Circuit Description/Diagram:  The upper 4 bits of the master is connected to the lower 4 bits of the slave as shown in the circuit diagram.  The base motor gets the signal from the first bit of the port 1(master) and the motor which is fixed at the spoon gets signal from second bit of the port1.  The shoulder link motor gets the signal from the first bit of port 1(slave) as shown.  Bits no. 10,11,12,13 are connected to the bits of RS-232 port to get the input from the Computer. xiv
  15. 15. Microcontroller Programming: We have done the microcontroller program tomove the servo motors at the required angle. For code see appendix.User Interface:We have provided a computerized user interface where a certain number coderepresents the certain motion.For base motion:2_1: Represent initial position.2_2: Rotate 20 deg rotation from initial.2_3: Again 20 deg rotation...So on till2_9. xv
  16. 16. For Shoulder link motion:1_1: Represent initial position.1_2: Rotate 20 deg rotation from initial.1_3: Again 20 deg rotation...So on till1_9.For spoon motion:3_1: Represent initial position.3_2: Rotate 20 deg rotation from initial.3_3: Again 20 deg rotation....So on till3_9.Working:  Initially, the arm is at its fixed position as in fig.1  The base is rotated to move the arm near the bowl according to user input, then the shoulder joint comes into action which places the spoon like structure inside the bowl (fig.2) according to user input.  The spoon is rotated to lift the liquid food (fig.3)  Then, base is rotated to move the arm towards the user; then again shoulder joint comes into action which moves the spoon towards the user’s mouth (fig.4) xvi
  17. 17. Fig.1 Fig.2Fig.3 Fig.4 ADAMS Simulation xvii
  18. 18. Costing:Manufacturing Cost (excluding Labour cost + R&D )S.NO Parts name Price(Rs.)/unit Quantity Price(Rs.)1 Servomotor 1500 3 4500 Hitec HS-322 HD2 Microcontroller kit 2000 2 4000 ATMEL 89S523 Transformer 100 2 2004 RS232 Cable 200 1 2005. Acrylic sheet 300/Sq ft. 1 sq. ft. 3006 Ball Bearing 10 4 407. Spoon 10 1 108 Base Board 100 1 1009. Miscellaneous 250 --- 250 (Glue,Nuts,alumi num strip ,cables, etc) TOTAL Rs. 9600/-  The prices stated are approximate depending upon market and quantity purchased.  On large scale production, the price of the final product can be reduced further. The cost of the product can come up to Rs.6000-7000. xviii
  19. 19. Conclusion:  The vibration occurring due to the servomotor limitation is a hurdle in smooth rotation of the arm which need to be addressed carefully.  Mechanical structure proposed and the capabilities of servomotors are not in full coordination, so some changes in structure is required.  More advanced microcontroller for better impulse sending and retrieving.  Use of sensors for detecting the food level and position of user.  Separate user interface in place of current interface for better ergonomics.  The angle rotation is 20 degree per pulse which should be further minimized up to 5 degree for better controlled movement of arm.  Aesthetic look have great scope to work upon and position of the circuit and bowl need to be adjusted more precisely.  For picking food objects as well as liquid, grippers/other mechanism can be proposed to handle different types of food. xix
  20. 20. References:http://www.robokits.comhttp://www.thinkindialab.comhttp://www.asel.udel.edu/roboticshttp://www.asel.udel.edu/roboticshttp://www.google.comhttp://www.asel.udel.edu/roboticshttp://www.asel.udel.edu/resna-sig13http://www.esnips.com xx
  21. 21. APPENDIX: i. Microcontroller Program:#include<at89x52.h>#define servo1 P1_1#define servo2 P1_2#define servo3 P1_3unsigned char select,angle,ptr=0;void timer1_ovf(void) interrupt 3{TH1=0xB7; //20msec //0xCA; //15 msec interruptTL1=0xFD; //0x00;switch(select){case 1: servo1=1;break; //servo on pulsecase 2: servo2=1;break; //servo on pulsecase 3: servo3=1;break; //servo on pulse}TR0=1;P0_4=~P0_4;}void timer0_ovf(void) interrupt 1{switch(angle){case 1:TH0=0xFD;TL0=0xD8;break;case 2:TH0=0xFD;TL0=0x1D;break;case 3:TH0=0xFC;TL0=0x62;break;case 4:TH0=0xFB;TL0=0xA7;break;case 5:TH0=0xFA;TL0=0xEC;break;case 6:TH0=0xFA;TL0=0x31;break;case 7:TH0=0xF9;TL0=0x76;break;case 8:TH0=0xF8;TL0=0xBB;break;case 9:TH0=0xF7;TL0=0xFA;break;}switch(select){case 1: servo1=0;break; //servo on pulsecase 2: servo2=0;break; //servo on pulsecase 3: servo3=0;break; //servo on pulse} xxi
  22. 22. TR0=0;}void UARTInit(void){SCON=0X50;T2CON=0X30;RCAP2H=0XFF;RCAP2L=0XFA; //57600 instruction per secondTH2=0XFF;TL2=0XFA;ES = 1;TR2 = 1;}void IRQ_UartGet(void) interrupt 4{unsigned char i;if(RI==1){RI = 0;i = SBUF;if(ptr==0){select=i;ptr++; ET1=0;ET0=0;}else{angle=i;ptr=0;ET1=1;ET0=1;}}}void main(){TMOD=0x11;ET1=1;ET0=1;TH1=0xB7;TL1=0xFE;TR1=1;TH0=0xFA; //shaft position to 0 1500 usecTL0=0x9A;UARTInit();EA=1;P1=0xF0;//Led=0;P3=0xFF;while(1){}} xxii
  23. 23. ii. Product Photos: Circuit Connection Full View of the Product xxiii

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