International Journal for Scientific Research & Development

IJSRD - International Journal for Scientific Research & Development| Vol. 8, Issue 3, 2020 | ISSN (online): 2321-0613

Design and Fabrication of Eight-Legged Kinematic Walker Vivek K T1 Nagaraju J H2 Nishanth G N3 Vinay Yadav D R4 Vinod Raj A5 1Assistant Professor 2,3,4,5Student 1,2,3,4,5Department of Mechanical Engineering 1,2,3,4,5NCET, Bangalore, India Abstract— As the wheels are ineffective on rough and rocky an engine or electric motors. Unlike wheels, legs move in an areas, therefore robot with one leg provided with Klan acute reciprocating movement. This is practically tough. mechanism is beneficial for advanced walking vehicles. It This is where Klan mechanism pitches in. It converts rotary can step over curbs, climb stairs or travel areas that are action directly into linear movement of a legged animal. currently not accessible on wheels. The most important Vehicles using this mechanism can travel on any type of benefit of this mechanism is that, it does not require surface. Also, they do not require heavy investments in road microprocessor control or large amount of actuator infrastructure. mechanisms. In this mechanism links are connected by pivot joints and convert the rotating motion of the crank into the II. LITERATURE REVIEW movement of foot similar to that of animal walking. The Describes the implementation of Disciples Simplex, an proportions of each of the links in the mechanism are autonomous evolvable system that controls the walking of defined to optimize the linearity of the foot for one-half of our eight-legged robot Leonardo. Disciples Simplex is based the rotation of the crank. The remaining rotation of the crank on GAs and logic system reconfiguration, and is allows the foot to be raised to a predetermined height before implemented into a single FPGA. As a result, a fully returning to the starting position and repeating the cycle. autonomous robot which is able to learn to walk with the aid Two of these linkages coupled together at the crank and of online evolvable hardware without any processors or off one-half cycle out of phase with each other will allow the line computation. John D et al. frame of a vehicle to travel parallel to the ground. The Described a coordinate of the coupler attachment project is useful in hazardous material handling, clearing points in two different coordinate frames, thereby reducing minefields, or secures an area without putting anyone at risk. the number of independent variables defining a suitable The military, law enforcement, Explosive Ordinance dyad for the desired rigid-body motion from five to two. Disposal units, and private security firms could also benefit After applying these geometric constraints, numerical from applications of mechanical spider. It would perform methods are used to size link lengths, locate joint axes, and very well as a platform with the ability to handle stairs and decide between RR, PR, RP and PP dyads that, when other obstacles to wheeled or tracked vehicles. The goal for combined, guide a rigid body through the best this project is to create an eight-legged robot to test new approximation, in a least squares sense, of n specified walking algorithm. We loosely based our design on spider positions and orientations, where n>5. No initial guesses of because there has an advanced way in robotics on Octopedal type or dimension are required. An example is presented locomotion. Hopefully algorithm develops will be of use to illustrating the effectiveness and robustness of this robotics community and in future society. approach. P.A. Simionescu, D. Beale, Keywords: Kinematic Walker, Walking Vehicle Analyzed the problem of optimum synthesis of the planar four bar function generator a practical case of the I. INTRODUCTION Ackermann steering linkage is considered. The reduced Since time unknown, man’s fascination towards super –fast number of design parameters of this symmetric four-bar mobility has been unquestionable. His never-ending quest linkage allowed inspecting the design space of various types towards lightning fast travel has gained pace over the past of objective functions through 3D representations, and their few decades. Now, with every passing day, man is capable properties suggestively highlighted. Rafael Avileset al., of covering longer distances in relatively shorter duration of presented an improved approach to the optimum time. Today’s automobile are beasts on wheel which are dimensional synthesis of planar linkages based on an elastic designed for speed and comfort. strain–energy error function, this method is suitable for any However, most of today’s automobile are limited to kind of kinematic synthesis for any planar linkage. Joseph roads or plain terrains. Even the off-road vehicles are of no M. Porta et al. use when the land is too rough, Needless to say, no vehicles Legged robots are well suited to walk on difficult can climb mountains. terrains at the expense of requiring complex control systems This is because all automobiles depend on rubber to walk even on at surfaces. It should be assumed that wheels which fare better only on roads. Man, who himself walking on abrupt terrain is the typical situation for a legged depends, on legs can travel on rocky terrains and climb robot. Mustafa SuphiErden, kamalleblebicioglu. mountains, but such journeys are never comfortable. Presented the problem of free gait generation and Thus, naturally the solution can be seen as an adaptability with reinforcement learning for an eight legged automobile which rests on and moves with legs. Simple, it robot. Continuous walking pattern with a larger average may sound but the problem in building a working model are stability margin. While walking in normal conditions with many. The most troublesome part is powering the gait of the no external effects causing instability, the robot is legs. Rotation of wheels in wheeled vehicles is powered by guaranteed to have stable walk, and the reinforcement

All rights reserved by www.ijsrd.com 249 Design and Fabrication of Eight-Legged Kinematic Walker (IJSRD/Vol. 8/Issue 3/2020/065) learning only improves the stability. Yu. F. Golubev and E. IV. EXPERIMENT PROCEDURE E. Selenskii. Investigated the dynamics of the locomotion of a six-legged walking robot in horizontal cylindrical pipes. The results of the numerical mathematical modeling of a statically stable locomotion of the robot are presented for its motion on the bottom semi-cylinder with viscous friction when this motion is arranged by alternating the supporting triangles. Alberto Aguado Behar. Discussed the design of a neuro PD control with gravity compensation for the generation of leg trajectories of a six-legged robot. The paper consists three parts parameters, finally in the third part also di A leg mechanism (walking mechanism) is a Fig. 1 mechanical system designed to provide a propulsive force Inside a lead-acid battery, the positive and negative by intermittent frictional contact with the ground. This is in electrodes consist of a group of plates welded to a contrast with wheels or continuous tracks which are connecting strap. The plates are immersed in the electrolyte, intended to maintain continuous frictional contact with the consisting of 8 parts of water to 3 parts of concentrated ground. Mechanical legs are linkages that can have one or sulfuric acid. Each plate is a grid or framework, made of a more actuators, and can perform simple planar or complex leadantimony alloy. This construction enables the active motion. Compared to a wheel, a leg mechanism is material, which is lead oxide, to be pasted into the grid. In potentially better fitted to uneven terrain, as it can step over manufacture of the cell, a forming charge produces the obstacles. positive and negative electrodes. In the forming process, the An early design for a leg mechanism called the active material in the positive plate is changed to lead Plantigrade Machine by Pafnuty Chebyshev was shown at peroxide (pbo₂). The negative electrode is spongy lead (pb). the Exposition Universally (1878). The original engravings Automobile batteries are usually shipped dry from for this leg mechanism are available. the manufacturer. The electrolyte is put in at the time of The design of the leg mechanism for the Ohio State installation, and then the battery is charged to from the Adaptive Suspension Vehicle (ASV) is presented in the plates. With maintenance-free batteries, little or no water 1988 book Machines that Walk. In 1996, W-B. Shieh need be added in normal service. Some types are sealed, presented a design methodology for leg mechanisms. The except for a pressure vent, without provision for adding artwork of Theo Jansen, see Jansen's linkage, has been water. The construction parts of battery are shown in figure. particularly inspiring for the design of leg mechanisms, as Sulfuric acid is a combination of hydrogen and well as the Klann patent, which is the basis for the leg sulfate ions. When the cell discharges, lead peroxide from mechanism of the Mondo Spider. the positive electrode combines with hydrogen ions to form water and with sulfate ions to form lead sulfate. Combining III. PRINCIPLE OF EIGHT-LEGGED KINEMATIC WALKER lead on the negative plate with sulfate ions also produces he The objective of this project is to convert concept of “four sulfate. Therefore, the net result of discharge is to produce bar mechanism” into a simple working physical model more water, which dilutes the electrolyte, and to form lead The scope of our project is to make this robot walk on any sulfate on the plates. Surfaces with a stiff gait slow and carries a limited load. It As the discharge continues, the sulfate fills the could be used for surveillance in sewer maintenance. pores of the grids, retarding circulation of acid in the active To give access to places which are dirty. To give access to material. Lead sulfate is the powder often seen on the places those are dangerous. Job which are highly difficult. outside terminals of old batteries. When the combination of The structure design of this kind of robots puts great weak electrolyte and sulfating on the plate lowers the output contribution to environmental adaptability and walking of the battery, charging is necessary. stability on complex and nasty non – structure environment. On charge, the external D.C. source reverses the This study presents a new type of six – legged walking current in the battery. The reversed direction of ions flows machine. This six-legged walking machine adopts new in the electrolyte result in a reversal of the chemical structure and tripod gait, as well as six legs driven by one reactions. Now the lead sulfates on the positive plate motor. It rotates about 360 degree using hydraulic system, reactive with the water and sulfate ions to produce lead so it reduces friction. One unique advantage of this walking peroxide and sulfuric acid. This action re-forms the positive machine is that the walking movement can be realized plates and makes the electrolyte stronger by adding sulfuric without any complex control system. A second advantage is acid. that the center of gravity height jitter of this machine is Arduino can be used to communicate with a negligible. human’s activities need to be replaced by computer, another Arduino board or other microcontrollers. machine. Mountain transport, Satellite detection, Disaster The ATmega328P microcontroller provides UART TTL relief and rescue, Mineral exploitation. Military affairs (5V) serial communication which can be done using digital pin 0 (Rx) and digital pin 1 (TX). An ATmega16U2 on the board channels this serial communication over USB and

All rights reserved by www.ijsrd.com 250 Design and Fabrication of Eight-Legged Kinematic Walker (IJSRD/Vol. 8/Issue 3/2020/065) appears as a virtual com port to software on the computer. The ATmega16U2 firmware uses the standard USB COM drivers, and no external driver is needed. However, on Windows, a .inf file is required. The Arduino software includes a serial monitor which allows simple textual data to be sent to and from the Arduino board. There are two RX and TX LEDs on the arduino board which will flash when data is being transmitted via the USB-to-serial chip and USB connection to the computer (not for serial communication on pins 0 and 1). A Software Serial library allows for serial communication on any of the Uno's digital pins. The ATmega328P also supports I2C (TWI) and SPI communication. The Arduino software includes a Wire library to simplify use of the I2C bus. Fig. 2.2: 2D View of Kinematic Walker – Top View V. RESULTS AND DISCUSSION The major demerit of wheel that is it gives poor performance on rocky and muddy areas. To avoid such case and keep the movement robots with legs by using Joe Klann Mechanism are proved to be best. These robots can travel into areas where the wheeled vehicle cannot. The legged robot is useful in explosive materials handling, detecting the bombs without harming any troop, etc. It can be used in security firms. Purpose of our project is to help the army to detect the bomb or minefields without putting lives of troops in risk.

Fig. 2.3: 2D View of Kinematic Walker – Right View

Fig. 2.0: 3D Model of Kinematic Walker

Fig. 2.4: 2D View of Kinematic Walker

VI. CONCLUSIONS Both the kinematic as well as dynamic analyzes of a six- legged robot have been carried out in the present study. The direct and inverse kinematic analysis for each leg has been conducted in order to develop the overall kinematic model of a six-legged robot. The problems related to trajectory generation of legs have been solved for both the swing and support phases of the robot. It is important to mention that trajectory planning problem during the support phase has been solved using the least squared method. An attempt has Fig. 2.1: Different Views of Kinematic Walker been made in present study to obtain optimal distributions of feet forces. It has been observed that the middle legs are subjected to more force than corner legs. Joint torques have been calculated using Lagrange-Euler formulation of the rigid multi-body system. The developed kinematic and dynamic models have been examined for tripod gait generation of the six-legged robot. This work can be

All rights reserved by www.ijsrd.com 251 Design and Fabrication of Eight-Legged Kinematic Walker (IJSRD/Vol. 8/Issue 3/2020/065) extended to tackle the problems related to tetrapod and non- [7] U.S. Patent No. 2,591,469, Animated Mechanical Toy, periodic gait of the walking robot. H. Saito (1952). An inverted slider crank mechanism for the front foot and crank-rocker for the back foot. ACKNOWLEDGEMENTS [8] U.S. Patent No. 4095661, Walking Work Vehicle, J. R. The satisfaction that accompanies the successful completion Sturges (1978). A lambda mechanism combined with a of any task would be incomplete without mention of the parallelogram linkage to form a translating leg that people who made it possible, whose constant guidance and follows the coupler curve. encourages crowned my effort of success. We take this [9] U.S. Patent No. 6,260,862, Walking Device, J. C. Klann opportunity to express deepest gratitude and appreciation to (2001). The coupler curve of a fourbar linkage guides all those who helped us directly or indirectly towards the the lower link of an RR serial chain to form a leg successful completion of this mini project work. mechanism, known as the Klann linkage. First and foremost, it's our immense pleasure to [10] U.S. Patent No. 6,481,513, Single Actuator per Leg thank our beloved project guide Mr. VIVEK KT, Assistant Robotic Hexapod, M. Buehler et al. (2002). A leg Professor, Department of Mechanical Engineering, mechanism that consists of a single rotating crank. Nagarjuna College of Engineering and Technology, [11] U.S. Patent No. 6,488,560, Walking Apparatus, Y. Bengaluru, for helping, guiding and strengthening us to Nishikawa (2002). Another rotating crank leg complete this project work. mechanism. We sincerely thank to our project coordinator Mr. AMARESH GUNGE, Assistant Professor, Department of Mechanical Engineering, NCET, Bengaluru, for her valuable advice, help, guidance and inspiration given to us in completing our project work. We would like to express our sincere thanks to Dr. N KAPILAN, Head of the Department, Department of Mechanical Engineering, Nagarjuna College of Engineering and Technology for his valuable suggestions and guidance throughout the period of this project report. We take this privilege to express our deep gratitude to Dr. SRIKANTA MURTHY K, Principal, Nagarjuna College of Engineering and Technology for his constant support and encouragement in preparation of this report and for providing library and laboratory facilities needed to prepare this project report. Last but not least, we would like to thank our parents, friends, teaching and non-teaching staff of Department of Mechanical Engineering, NCET. NAGARAJU J H 1NC16ME071 NISHANTH G N 1NC16ME074 VINAY YADAV D R 1NC16ME115 VINOD RAJ A 1NC16ME116

REFERENCES [1] U.S. Patent No. 469,169 Figure Toy, F. O. Norton (1892). [2] U.S. Patent No. 1,146,700, Animated Toy, A. Gund (1915). A leg mechanism formed by an inverted slider- crank. [3] U.S. Patent No. 1,363,460, Walking Toy, J. A. Ekelund (1920). A leg mechanism formed by a rotating crank with extensions that contact the ground. [4] U.S. Patent No. 1,576,956, Quadruped Walking Mechanism, E. Dunshee (1926). A four-bar leg mechanism that shows the coupler curve forms the foot trajectory. [5] U.S. Patent No. 1,803,197, Walking Toy, P. C. Marie (1931). Another rotating crank leg mechanism. [6] U.S. Patent No. 1,819,029, Mechanical Toy Horse, J. St. C. King (1931). A crank-rocker leg mechanism with a one-way friction mechanism in the foot.