Shirsha Yaathra - Head Movement controlled Wheelchair - Research Paper

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This is the research paper of a project carried out by 8 member group including myself.

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Shirsha Yaathra - Head Movement controlled Wheelchair - Research Paper

  1. 1. Controlling a Wheelchair According to the Head Movements Dimutu Upeksha*, Chameera Wijebandara, Chamila Dilshan Wijayarathna, Sameera NilupulWijayarathna,Milinda Fernando, Akila Pemasiri, Suneth Vijaindu Gamage, Madhushi Niluka Bandara Department of Computer Science and Engineering, University of Moratuwa, Sri Lanka dimuthu.upeksha2@gmail.com; chameerawijebandara@gmail.com; cdwijayarathna@gmail.com;sameernilupul@gmail.com; milindasf@gmail.com; akilapemasiri@gmail.com; svijayindu@gmail.com; madhushib@gmail.com; +94 -719-084-638 1
  2. 2. Table of ContentsAbstract………………………………………………………………………………………………… 031.Introduction……………………………………………………………………………………….. 032.Materials and Method 2.1 Materials……………………………………………………………………………………….. 03 2.2 Method…………………………………………………………………………………………. 04 2.3 Implementation 2.3.1 Identifying the circuits embedded in the wheelchair……………………………………… 05 2.3.2 Identifying voice commands……………………………………………………………… 05 2.3.3 Controlling the movements of the wheelchair…………………………………………….. 05 2.3.4 Collision Avoider…………………………………………………………………………... 053. Results………………………………………………………………………………………………. 084. Discussion…………………………………………………………………………………………... 085. Conclusion………………………………………………………………………………………….. 096. Acknowledgement………………………………………………………………………………….. 097. Reference…………………………………………………………………………………………… 09Appendices …………………………………………………………………………………………… 10 2
  3. 3. Abstract - The thirty-year long civil war in our set about designing a mobility control systemcountry left many young and able-bodied men that is capable of interfacing with headand women with life-long disabilities. The movements of the officer as that is the only partsoldiers who fought for the defence of our of his body that can be moved. Based on amotherland and civilians caught in the crossfire lightweight harness worn on the head and usinghave suffered grievous injuries that led them to a solid-state gyroscope proving a tilt-sensorbe wheelchair-bound for mobility. However, for capability.some of the most severely injured war heroes,even a wheelchair cannot provide mobility. The The mobility control system was then interfacedmotivation for this engineering research project to a battery-powered motorized wheelchair byis to invent a wheelchair mobility control system removing the joystick-based control unit of thefor an army officer who has lost all motor wheelchair and replacing it with our invention.control functionality below his neck and is only The prototype was successfully tested for theable to move his head. complete set of motions that the disabled officer wishes to make. The next step in thisOn a visit to the longterm-care facility in which engineering project is to further research onthis officer resides, his only request was to be providing safety and reliability features for theable to move his wheelchair unassisted by mobility control unit.another. Our team of engineering undergraduates 2. Materials and Method 2.1 Materials1. Introduction - As a result of civil war Material Quantity which existed for three decades there are LYEB103 Wheel 1 many soldiers who have been affected. So Chair(Electric Wheelchair) as engineering students we thought that it is Arduino Mega 2560 1 our responsibility to utilize our knowledge development board and capabilities in a way that is beneficial to Arduino Compatible Voice 1 the country. The motivation behind this recognition Module ZCT245AN-TTL 2-axis tilt 1 project is to support for such an officer who sensor has not control below his neck. HC-SR04 Ultra Sonic 8 range finders At the moment he is staying at Mihindu Seth PIC 16f876 micro 1 Madura. What we noticed was that he controller cannot do anything of his own. What he 10kΏ surface mounts 40 40 requested mainly was a way to move his (for R2R Ladder) wheel chair of his own. 330Ώ surface mounts 10 7805 Regulator IC 1 So we came with up an idea to carry on a 4MHz crystal oscillator 1 project which results in making a wheel chair which can be moved according to the head movements of the officer’s head. 3
  4. 4. 2.2 Method The overall logic behind this project can details refer the state diagram in the be illustrated as follow. For further appendices Power on the wheelchair Power In Wheelchair Check voice Check voice Obstacle is Check voice command is command is detected command is “Drive” “Stop” “Manual” Start Head Stop the movement Stop Head Recoded user Control towards the obstacle Control guidance is played Power off Yes 4
  5. 5. 2.3 Implementation2.3.1Identifying the circuits embedded in the  The commands used are “Drive”, “Stop”wheelchair and “Manual”. The wheelchair selected was LYEB103. 2.3.4Controlling the movements of the Dissembled the control unit in the wheelchair wheelchair.  According to the head movements We identified that a removal of one  According to the input signal (which component will even lead the wheelchair to was generated by tilt sensor), be locked, to the safety of the user. Arduino Uno board generates the Then we identified the inputs and outputs of relevant digital signal. the joystick by the means of an oscilloscope  Those signals are converted to (Figure (a)) signals which are analogous to the We supplied the analog voltages using two output signals of the joy stick and variable resistors and deceived the circuit. given to the relevant ports of the As the prior step was successful we supplied control circuit. digital values using digital to analog  According to the voice commands converters (Figure (b))  The original control circuit uses inputs from switches to control power and speed.2.3.2 Identifying the head movements.  According to the input signal (which ZCT245AN-TTL 2-axis tilt sensor was used, was generated by Arduino which is connected to the head of the user. compatible, voice recognition), This can measure the angles with reference Arduino Uno board generates the to the x axis as well as the y axis of the relevant signal. horizontal plane(Figure (c)).  The circuit is developed so that the Through a serial interface the angle tasks done by switches take place measured by the tilt sensor is caught by an according to the generated signals. Arduino Mega board which contains the driving program of the wheelchair. 2.3.4 Collision Avoider  8 sonar sensors were used to identify the barriers which are along and on the sides2.3.3 Identifying the voice commands of the moving wheelchair.  By measuring the distance to the Arduino compatible, voice recognition obstacles from the wheelchair, position shield was mounted on the Arduino Uno of the obstacle is found. board.  By using a clock interrupt the obstacles It can be configured to recognize 15 voice are checked in regular intervals and the commands. movement of the wheelchair is It generates and sends a signal to the terminated if there is an obstacle in the Arduino Uno board according to the relevant direction command received. 5
  6. 6. 1 2 3 4 1. Vref 2. Vcc 3. X 4. Y 5. X5 6 7 8 6. Y 7. GND Figure (a) 8. Vref/ Not Connected Figure (b) 6
  7. 7. Figure (c) 7
  8. 8. 3. Results - Some quantitative factors were 100 taken into the accountant to measure the 90 Accuracy Level (%) accuracy and reliability of the system 80 The response time of the tilt sensor – The 70 time taken between giving the input and 60 receiving the output (response time) was 50 40 measured 30 20 225 10 200 0 Response Time (ms) 175 1st 2nd 3rd 4th 5th 150 Testing Session 125 100 75 50 25 4. Discussion - The movement detecting 0 module of the developed system is very 1st 2nd 3rd 4th 5th flexible as it takes relative readings. That Testing Session makes it enable for the user to operate the system having any initial position. The user can move not only to a limited number ofIn the final result the response time is 10ms(approximately) and at the time of stopping the directions, but he also can move to anywheel chair, in first few test sessions a direction that he wishes. Also he can turn, while moving forward or backward.significant time was taken to slowdown and tostop. But after few improvements it was reduced The voice recognition and responsibleand a sudden stop can be handled now. module works accurately in general circumstances. But in some practical The accuracy level of the voice recognition module – To measure the accuracy level of situations when there is a very large noise this module may not be able to recognize the the voice recognition module testing was carried out by giving voice commands and commands and distinguish between the getting the responses. commands. The obstacle avoidance module of the system works in proper manner. But it needs a well maintenance because the dust particles on the sensors may reduce its detecting ability and the accuracy. The main benefit of this system is this can be easy interfaced to any kind of wheelchair through an appropriate motor controller and the voice commands can be tailored to the each user according to their preference. 8
  9. 9. 5. Conclusion - The prototype we developed is Also we would like to convey our gratitude to fully functional and it provides a very good Dr. Upali Khomban, President of Computer solution to the identified problem. Science and Engineering Society, who gave us necessary information to proceed in project. He Even though in the short term we aimed always communicated with us, look at current only for this particular army officer, he is progress and motivate us to do the project. We not the only one with this problem. There are many army soldiers and officers in the also thank Lt. Col. Athula Samarasinghe who same condition in Sri Lanka. motivated us to do this project. Moreover considering about the whole We would also like to convey our special thanks world it has been estimated that there are to “Brandix Apperal Ltd” who donated an more than 50,000 individuals who don’t electric wheelchair for this task. have use of their arms and legs (quadriplegics). Majority of them are war In addition we like to thank Maj. Madugoda of heroes of developing countries as Sri Lanka. “Mihindu Seth Madura” and official there, who helped us to go there and do necessary tastings. As this invention is a safe, reliable and They also helped us in finding a suitable economical for the purpose, these people would be able to upgrade their living motored wheelchair for our project. standard at least for some extent by using At last but not in least we would like to thank all this product. who helped and motivated us. So our idea is, that by expanding this 7. References – product we would be able to support to the  http://arduino.cc/en/Main/ArduinoBoard social and economical development as a Mega/ whole, while supporting to those suffering lives.  Data sheet of Arduino Compatible Voice recognition Module6. Acknowledgement - First on foremost, we  Data sheet of ZCT245AN-TTL 2-axis would like to thank, Head of the Department tilt sensor of Computer Science and Engineering,  Data sheet of HC-SR04 Ultra Sonic University of Moratuwa, Eng. Lt. Col. Dr. range finders Chandana Gamage who guided us through  Data sheet of PIC 16f876 micro doing this project, provided important controller advices, helped us in difficult periods and  Data sheet of 10kΏ surface mounts 40 provided equipment for our project. His (for R2R Ladder) willingness to motivate us contributed  Data sheet of 330Ώ surface mounts tremendously to our project. Besides we  Data sheet of 7805 Regulator IC would like to thank CSE staff who helped us by giving advices and providing equipment which we needed. 9
  10. 10. AppendicesThe system architecture is depicted below. Main sensor which tracks the head Main Circuit Module movement Board of Wheel converting Chair Tilt Sensor digital signal in to analog US1 R2R Ladder US2 Arduino Board (PIC) Voice Recognition Model US3 To activate the US4 system by voice MP3 module command for voice To avoid responses Show the current obstacles and state for safety Of the wheelchair 10
  11. 11. The state chart of the system is depicted below 11

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