Human Hand Emulator free essay sample

The Human Hand Movement Emulator combines concepts of Mechanical and Electronics Engineering to form a robotic emulator hand, that can grip, move and perform similar tasks as done by a human hand at places that are inaccessible or not fit for the human hand. CHAPTER 2: WORKING PRINCIPLE: The robotic arm will work in two modes. 1. Input by human: The robotic arm will emulate the actions performed by human arm. This will be done using a virtual arm which will be controlled by the human. The microcontroller will sense the motions performed by the irtual arm, understand them and output signals to the robotic arm. The robotic arm will move based on the signals provided by microcontroller. 2. Pre-programmed set of motions: The microcontroller will be fed with a program. This program will contain pre-determined set of movements. According to the instructions provided in the program, the robotic arm will perform the movements. We will write a custom essay sample on Human Hand Emulator or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page This mode of operation is generally useful in assembling. CHAPTER 3: Background of the project 3. 1 ARDUINO-An open source electronics prototyping platform Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. Its intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments. Arduino can sense the environment by receiving input from a variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The microcontroller on the board is programmed using the Arduino programming language (based on Wiring) and the Arduino development environment (based on Processing). Arduino projects can be stand-alone or they can communicate with software running on a computer (e. g. Flash, Processing, MaxMSP). An Arduinos microcontroller is also pre-programmed with a boot loader that simplifies uploading of programs to the on-chip flash memory, compared with other devices that typically need an external programmer. fig 3. 1 1-USB jack, 2-Power jack, 3-Power selection jumper, 4-Digital pins, 5-Analog I/p pins, 6-Power pins, 7-Reset button. Digital Pins In addition to the specific functions listed below, the digital pins on an Arduino board can be used for ipin has an internal pull-up resistor which can be turned on and off using digitalWrite() (w/ a value of HIGH or LOW, respectively) when the pin is configured as an input. The maximum current per pin is 40 mA. * Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data. On the Arduino Diecimila, these pins are connected to the corresponding pins of the FTDI USB-to-TTL Serial chip. On the Arduino BT, they are connected to the corresponding pins of the WT11 Bluetooth module. On the Arduino Mini and LilyPad Arduino, they are intended for use with an external TTL serial module (e. g. the Mini-USB Adapter). * External Interrupts: 2 and 3. These pins can be configured to trigger an interrupt on a low value, a rising or falling edge, or a change in value. See the attachInterrupt() function for details. * PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function. On boards with an ATmega8, PWM output is available only on pins 9, 10, and 11. * BT Reset: 7. (Arduino BT-only) Connected to the reset line of the bluetooth module. SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI communication, which, although provided by the underlying hardware, is not currently included in the Arduino language. * LED 13. On the Diecimila and LilyPad, there is a built-in LED connected to digital pin 13. When the pin is HIGH value, the LED is on, when the pin is LOW, its off. Analog Pins In addition to the specific functions listed belo w, the analog input pins support 10-bit analog-to-digital conversion (ADC) using the analogRead() function. Most of the analog inputs can also be used as digital pins: analog nput 0 as digital pin 14 through analog input 5 as digital pin 19. Analog inputs 6 and 7 (present on the Mini and BT) cannot be used as digital pins. * I2C: 4 (SDA) and 5 (SCL). Support I2C (TWI) communication using the Wire library (documentation on the Wiring website). Power Pins * VIN (sometimes labelled 9V). The input voltage to the Arduino board when its using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin. Note that different boards accept different input voltages ranges, please see the documentation for your board. Also note that the LilyPad has no VIN pin and accepts only a regulated input. * 5V. The regulated power supply used to power the microcontroller and other components on the board. This can come either from VIN via an on-board regulator, or be supplied by USB or another regulated 5V supply. * 3V3. (Diecimila-only) A 3. 3 volt supply generated by the on-board FTDI chip. * GND. Ground pins. Other Pins * AREF. Reference voltage for the analog inputs. Used with analogReference(). * Reset. (Diecimila-only) Bring this line LOW to reset the microcontroller. Typically used to add a reset button toshields which block the one on the board. Arduino projects can be stand-alone or they can communicate with software running on a computer (e. g. Flash, Processing,  MaxMSP). An Arduinos microcontroller is also pre-programmed with a boot loader that simplifies uploading of programs to the on-chip  flash memory, compared with other devices that typically need an external  programmer. ATmega8A Microcontroller The Atmel ATmega8A is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega8A achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed. The ATmega8A has 8 KB of flash memory for storing code (of which 2 KB is for the boot loader), 1 KB of â€Å"SRAM† and 512 bytes of â€Å"EEPROM† (which can be read and written with the EEPROM library). . 2 Servo motor A  Servomotor  is a  rotary actuator  that allows for precise control of angular position. It is a  closed-loop  servomechanism that uses position feedback to control its motion and final position. The input to its control is some signal, either analogue or digital, representing the position commanded for the output shaft. A servo motor consists of several main parts, the motor and gearbox, a position sensor, an e rror amplifier and motor driver and a circuit to decode the requested position. Servomechanism It is an automatic device that uses error-sensing  negative feedback  to correct the performance of a mechanism. Position control A common type of servo provides  position control. Servos are commonly electrical or partially electronic in nature, using an electric motor  as the primary means of creating mechanical  force. Other types of servos use  hydraulics,  pneumatics, or magnetic  principles. Servos operate on the principle of negative feedback, where the control input is compared to the actual position of the mechanical system as measured by some sort of  transducer  at the output. Any difference between the actual and wanted values (an error signal) is amplified (and converted) and used to drive the system in the direction necessary to reduce or eliminate the error. This procedure is one widely used application of  control theory. Block diagram fig 3. 2 Servo Motor control: Servo motors have three wires: power, ground, and signal. The power wire is typically red, and should be connected to the 5V pin on the Arduino board. The ground wire is typically black or brown and should be connected to a ground pin on the Arduino board. The signal pin is typically yellow or orange and should be connected to pin 9 on the Arduino board. The potentiometer should be wired so that its two outer pins are connected to power (+5V) and ground, and its middle pin is connected to analog input 0 on the Arduino. CIRCUIT DIAGRAM: fig 3. 6 3. 3 Potentiometer A potentiometer informally, a pot, within electronics technology is a component, a three-terminal resistor with a sliding contact that forms an adjustable voltage divide. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. A potentiometer is essentially a voltage divider used for measuring electric potential (voltage). Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick. Potentiometers comprise a resistive element, a sliding contact (wiper) that moves along the element, making good electrical contact with one part of it, electrical terminals at each end of the element, a mechanism that moves the wiper from one end to the other, and a housing containing the element and wiper. Potentiometers can be used as position feedback devices in order to create closed loop control, such as in a  servomechanism. 3. 4 Flex sensors Flex sensors are sensors that changes the resistance depending on the amount of bend on the sensor. They convert the change in bend to electrical resistance-more the bend the more the resistance value. Flex sensors are usually in the form of a thin strip from 1-5 long that vary in resistance. Working Principle: Flex sensors are analog sensors and they work as variable analog dividers. Flex sensors are carbon resistive elements within a thin flexible substrate. More the carbon means lesser will be resistance. When the substrate is bent the sensor gives the output resistance relative to the bend radius. More the bend radius more will be the resistance value. fig 3. 7 Types of Flex sensors: 1. Uni-Directional 2. Bi-Directional Uni-Directional Flex Sensors One directional Flex Sensor is a unique component that changes resistance when bent or flexed . An un flexed sensor Style A has a nominal resistance of approximately 10,000 ohms (10 K). As the flex sensor is bent in one direction the resistance gradually increases. Range of resistances of the FLX-03 Style A sensor may vary between 10K and 40K depending upon the degree of the flex. An un flexed sensor Style B begins with a infinitely high nominal resistance. As the flex sensor is bent in one direction the resistance gradually decreases. Range of resistances of the FLX-03 Style B sensor may decrease to under 10K depending upon the degree of the flex. fig 3. 8 Some applications for the Flexible Bend Sensor are: * Collision detection on mobile robots VR Gloves and VR suits * Physics applications and experiments CHAPTER 4: Block diagram fig 4. 1 Explanation The hardware operates in a way that when you receive a serial input from potentiometer or flex sensors that tells the arduino to perform conversion of analog to digital data, the MCU would read the inputs and sends corresponding PWM output and then send it to the servo, which is connected to a potentiometer or sensor to determine its angular position. The servos are powered by an external DC power supply. Servos are controlled by sending them a pulse of variable width. Given the rotation constraints of the servo, neutral is defined to be the position where the servo has exactly the same amount of potential rotation in the clockwise direction as it does in the counter clockwise direction. The potentiometers were used to determine the position of the base and flex sensors for elbow joints. It gave back to the microcontroller a voltage feedback that was relative to the rotation. The ground and power lines are connected to the Arduino’s ground and Vcc. The wiper connections go into the arduino’s analog input pins. As the joint rotates the voltage changes linearly with the rotation. DC Power Supply to provide 5 Volts of power to the servos. CHAPTER 5: APPLICATIONS * Bomb disposal: to provide safety to the bomb disposal squad by providing an extra line of defense. * To lift nuclear wastes without harming the humans. * Mine disposal (dispose of old or unstable explosives, such as ones used in  quarrying  or  mining). * The robotic arm can be designed to perform any desired task such as welding, gripping, spinning etc. , depending on the application. For example robot arms in automotive assembly line perform a variety of tasks such as wielding and parts rotation and placement during assembly. In space the space shuttle Remote Manipulator System have multi degree of freedom robotic arms that have been used to perform a variety of tasks such as inspections of the Space Shuttle using a specially deployed boom with cameras and sensors attached at the end effector. * The robot arms can be autonomous or controlled manually and can be used to perform a variety of ta sks with great accuracy. The robotic arm can be fixed or mobile (i. e. wheeled) and can be designed for industrial or home applications. Robotic hands often have built-in pressure sensors that tell the computer how hard the robot is gripping a particular object. This keeps the robot from dropping or breaking whatever its carrying. Other end effectors include blowtorches, drills and spray painters this improves their performance. The scope of use of a robotic arm is very vast. There are numerous fields in which using manpower is dangerous. This project will try to act as substitute at these fields and decrease the load of risk that humans have to face. In many of the above stated applications, humans working in those conditions can be harmful. What we aim to do with this project is that the robotic arm will be used in place of humans. Taking one of the examples from above, it’s very difficult to execute precision work in sub-zero temperatures. So, we use the robotic arm to perform these tasks. CHAPTER 6: FUTURE SCOPE: * The robotic arm so far designed is able to lift the objects. It is able to lift the objects of medium weight. In order to extend it to some extent, more advanced tools and material with the capacity to withhold the heavy weight objects are to be used, which is then applicable in warfront and used as a rescuer at several places where there is a need and also in industrial areas, military, and so on. We would like to continue this project for the next year while extending some of the functionalities. We would like to make the project portable by adding motion as one of the features. We would also like to add wireless remote control and camera to make it flexible, thus increasing its fields of usage. REFERENCES: http://www. arduino. cc (About Arduino kit)? http://science. howstuffworks. com/robot2. htm (Basic Structure Of Robotic Arm)? Saha, H. K. Introduction To Robotics. Tata McGraw-Hill Education, 2008.? Banzi, Massimo. Getting Started With Arduino. OReilly Media, 2011.?