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ME- 362 Instrumentation and Measurement Sessional A brief look into “ THOR ” or the “ T errain H azard O ptimized R obot”. Presented by Group A 15 Roll No Student Name 0510005 Naser Imran Hossain *
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ME- 362Instrumentation and Measurement SessionalA brief look into “ THOR ” or the “ Terrain Hazard Optimized Robot” Presented by Group A 15 Roll NoStudent Name 0510005 Naser Imran Hossain * 0510014 Md. Rokanuzzaman Khan 0510024 Prajnaprasun Bhattacharjee 0510033 Nahid Pervez
Presentation Overview • Introduction • Objectives & Features • Mechanical orientation • Circuitry • Purpose • Critique • Optimization & Future plans • Conclusion • Acknowledgments
Introduction • Since Karel Capek (1890-1938) first used the word ‘robot’, man has been infatuated with the creation of mechanized companions. • Our project was named after the Norse god Of thunder who use to banish evil to their demise. For it too might one day help humanity in its struggle against the evils of pollution and contamination. • Our inspiration was the brave remote neutralization of a possible catastrophe by one of our hon’ teachers when a jammed Co-60 source of the γ-beam irradiator at Bangladesh Institute of Nuclear Agriculture (BINA) threatened the lives of many in the late 80’s.
The Project - “ THOR ” The team Attendees
Objectives • Manually maneuver into hazardous environment. • Avoid obstacles and detours on the way using fast directional control. • Grip mission objectives with link-driven gripper • Bring objective back into safe containment area and deposit. • Sense heightened level of temperature or lack of light on due process and indicate.
Features • Custom designed “ Gripper Arm ” • Multidirectional “Pseudo Holonomic” Control. • Smart ‘ Ambient ’ light and heat sensing. • High torque driving mechanism for heavy payloads. • Minor object avoidance.
Mechanical Orientation Gripper Arm Part 1: The “ Grip ” • Acrylic made to reduce weight. • Wire manipulated. • Maximum jaw clearance 8mm. • Spring operated auto recoiling. • Designed to always assume a vertical position during operation. • Gripping control by gear-motor. Fig : The Grip
Consists of 4 acrylic links in total Supports the vertical positioning of the grip/claw. Counter supports each other in cases of heavier payloads. Arm leverage and height controlled by wires and a gear motor. Part 2: The “Arm” Mechanical Orientation (cont) Fig: The Arm
Separate gear motors control individual wheels, crane fulcrum and gripper. Polarity is changed instantaneously with DPDT switches. Navigation Strategy Part 1: Hardware Mechanical Orientation (cont)
Both wheel rotate in common directions to go forward or backward. To ensure Pseudo-Holonomic movement, motors are coupled to the forward wheels only. Part 2 : Mechanics Mechanical Orientation (cont)
Mechanical Orientation (cont) • RW rotates opposite to LW to change direction and vice versa. • Smooth turns are made possible by stopping one of the wheels and resuming the other
Part 1: Overview & Functions LDR senses lack of light and indicates with a Green LED. NTC-Type thermistor senses increase in temperature and indicates with a Red LED Possible to calibrate sensors according to ambient variables. In circuit “ Operational Amplifier ” ( LM-324 ) synchronizes between sensor feedbacks and indicators. Circuitry
Circuitry(cont) • Sensing lack of light • Under full incident light (spectral range of 515 nm ~ 730 nm ) , LDR, with its decreased resistance, renders the path to the LED inactive. • In darkness, its resistance increases. Op-Amp compares the feedback and lights up the green LED.
Circuitry(cont) • Sensing heightened temperature • Under increased temperature, the NTC type thermistor resistance is decreased rendering it inactive in the circuit. Op-Amp again compares the feedbacks and lights up the red LED. • When ambient temperature recedes to normal, the resistance increases cutting off power supply to the LED.
Part 2: Logistical Consideration Over the range of -50°C to 150°C, NTC thermistors offer a distinct advantage in sensitivity to temperature changes compared to other temperature sensors like Pt-RTD. Thermistors are also easily available and relatively cheap. Circuitry(cont) Fig: Resistance Vs Temp Graph
Circuitry(cont) • Light Dependent Resistors (LDR) provide a comfortable range of resistive outputs to work with. • Like the thermistor, LDRs are also easily available and relatively cheap. • Variable resistors are used to calibrate circuit in contemporary environment. Fig: Resistance Vs Light Intensity graph
Reconnoitering through possibly radioactive or hazardous environment. Salvage mission over terrains unsuitable for human exposure. Charting terrain as a drone for possible thermal leakage , heat flux and variation is luminescence. THOR at its infancy, is but only an engineering project. However with proper planning it maybe employed in a variety of useful purposes:- Purpose
Purpose (cont) Animation showing THOR’s dynamic movements
Critique • Acrylic parts are vulnerable to sudden shock-loads. • The wiring of the motors and DPDT switches often breaks loose. • The bead type thermistor is not as well responsive as the LDR. So the signaling might be delayed • The wires used for gripper and arm-control is not that strong in tension and might sever under heavy payloads.
Replacing acrylic parts with stronger materials, like HDPE (High Density Poly Ethylene) or Aluminum. Integrating radio frequency control and servo drives. Incorporating solar-power for prolong operation. Automating directional commands via microcontrollers. Replacing LDR with more sensitive sensors such as phototransistors. How to Optimize the current configuration? Optimization & Future plans
Application in humanitarian services like minesweeping, scavenging battle debris. Stellar and interstellar explorations. What prospect does THOR’s future hold? Optimization & Future plans
Conclusion At the end, we can only hope that we were able to achieve what we set out to do at the beginning of the course. We learned much throughout the semester, about mechanical and electrical components and most importantly about human resource management. However, all in all that was quite a delightful experience.
Dr. M.A. Taher Ali. Professor, Dept. of Mechanical Engineering A.K.M Monjur Morshed Assistant Professor, Dept. of Mechanical Engineering Md. Wasim Akram Lecturer, Dept. of Mechanical Engineering Md. Al Amin Khan Chowdhury Lecturer, Dept. of Mechanical Engineering Abdul Motin Lecturer, Dept. of Mechanical Engineering Mr. Masudur Rahman Assistant Instrumentation Engineer For the completion of our project, we are greatly indebted to the following persons. Without their guidance, it would’ve been impossible to go through such an endeavour. Acknowledgments
Visit http://project-thor.pbwiki.com If you have any further queries. Thank you all for joining in.