Mechanical Spider

International Journal of Mechanical Engineering and Computer Applications, Vol 1, Issue 5,Special Issue, October 2013, ISSN 2320-6349

All copyrights Reserved by eETECME-2013, Marathwada Mitra Mandals polytechnique.Theragaon , Pune, India , Published by IJMCA (www.ijmca.org) Page 13

Mechanical Spider by Using Klann MechanismN. G. Lokhande* , V.B. Emche**Assistant professor ,Department of

Mechanical EngineeringShri Datta Meghe Polytechnic,

Hingna Nagpur-16. Indiaemail: [email protected] , [email protected]

ABSTRACT -As the wheels are ineffective on rough and rocky areas,therefore robot with legs provided with klann mechanism isbeneficial for advanced walking vehicles. It can step overcurbs, climb stairs or travel areas that are currently notaccessible with wheels. The most important benefit of thismechanism is that, it does not require microprocessor controlor large amount of actuator mechanisms. In this mechanismlinks are connected by pivot joints and convert the rotatingmotion of the crank into the movement of foot similar to that ofanimal walking. The proportions of each of the links in themechanism are defined to optimize the linearity of the foot forone-half of the rotation of the crank. The remaining rotation ofthe crank allows the foot to be raised to a predeterminedheight before returning to the starting position and repeatingthe cycle. Two of these linkages coupled together at the crankand one-half cycle out of phase with each other will allow theframe of a vehicle to travel parallel to the ground. This projectis useful in hazardous material handling, clearing minefields,or secures an area without putting anyone at risk. Themilitary, law enforcement, Explosive Ordinance Disposal units,and private security firms could also benefit from applicationsof mechanical spider. It would perform very well as a platformwith the ability to handle stairs and other obstacles to wheeledor tracked vehicles.The goal for this project is to create an eight-legged robot totest new walking algorithm. We loosely based our design onspider because there has an advanced way in robotics onoctopedal locomotion. Hopefully algorithm develops will be ofuse to robotics community and in future society.Keywords Klann mechanism, leg design, walking robot

I. INTRODUCTIONThis walking robot is based on klann mechanism klannmechanism is a planar mechanism designed to simulate thegait of legged animal and function as a wheel replacement.The linkage consists of the frame, a crank, two groundedrockers, and two couplers all connected by pivot joints. It has6 links per leg 180 degrees of crank rotation per stride. 2 legswill replace a wheel Clockwise rotation of the crank.

1. Step height is achieved by rotating the connecting armwhich is attached to the crank on one end and the middle ofthe leg on the other. It pivots on a grounded rocker.2. The proportions of each of the links in the mechanism aredefined to optimize the linearity of the foot for one-half ofthe rotation of the crank. The remaining rotation of thecrank allows the foot to be raised to a predetermined heightbefore returning to the starting position and repeating thecycle. Two of these linkages coupled together at the crankand one-half cycle out of phase with each other will allowthe frame of a vehicle to travel parallel to the ground.3. The Klann linkage provides many of the benefits of moreadvanced walking vehicles without some of theirlimitations. It can step over curbs, climb stairs, or travel intoareas that are currently not accessible with wheels but donot require microprocessor control or multitudes of actuatormechanisms. It fits into the technological space betweenthese walking devices and axle-driven wheels.

II. LITERATURE REVIEW2.1 Existing Design of the leg mechanism

For legged robots, 2 DOF is the minimum required to movea leg forward by lifting and swinging. Figure 1 shows theleg mechanism, using a Watt-chain six-bar mechanism toimitate the cockroach (insect) leg. We chose a six barmechanism because of its superior force-transmission angleand bigger oscillating angle in comparison with other typessuch as the four-bar mechanism (Norton, 2004). Forcetransmission is very important for leg mechanisms, becauseof the point contact with the ground. The leg mechanismitself has one DOF for lifting, whilst the base of mechanismhas another DOF for swinging. The leg mechanism, with itsbody size shown in Figure 1, is modeled with Solid Works.It has six links and seven cylindrical joints. The body sizeand link dimensions are determined from the maximumswing and lift angles. Each link is created by entering itsshape and reference coordinates. To mate the contactsurfaces of the parts, the assembly bar of the assembly-



mating menu is used. Then the component is rotated aroundan axis, specifying the desired axis and rotation for theselected surfaces. To generate more stable walking on roughground and mimic muscles, the springs are mountedbetween link1 and link2 and between link2 and link3 [1].

Figure 1 Design of the leg mechanism2.2 Mechanical Design of A Quadruped Robot

It is a quadruped, electrically actuated, walking and wall-climbing robot. The trunk consists of one part only, and thelegs are mounted, symmetrically, on the corners of thetrunk, Fig. 2. Each leg has three links and three actuatedjoints connecting these links. Hip horizontal joint is used toswing the three links of the leg in a plane parallel to theground while walking, hip vertical joint, to attach-detach thefoot on and from the terrain for swing and support stages,respectively [2].

Figure 2 The robot, and the leg

2.3 Theo Jansen mechanism forClimbing over bumpsTransporter vehicles have traditionally used wheelMechanisms like cars and trains. Wheels are ideallysuited for movement without vertical fluctuations ofthe body, and tires with inner rubber tubes absorbshock from a rugged road. On the other hand,biologically-inspired robotics learn mobile flexibilityfrom the morphology of multiple legs and theircoordination .Good examples of this are arthropods,like spiders, and the robots are conventionallydesigned with actuators placed in every joint. In suchimplementation, robots are good tools to investigatehow an animal moves, but they are unable to be asubstitute principle for wheels because they dontmuch take into account the maximum load capacity.Joints actuators promise mobile flexibility, while theActuators torque performance impacts on thetoughness of the robots body. Therefore, in thedesign of disaster robots, which need to move onrubble and carry rescue devices, continuous tracks orcrawlers are popular.Theo Jensen a Dutch kinetic artist who has attemptedto create a bridge between art and engineering byfocusing on biological nature, proposed a linkagemechanism to mimic the skeleton of animal legs.This is called Theo Jansen mechanism, andprovides the animal with a means of moving in afluid manner. Interestingly, his artificial animalsrequire no electric power for actuators, and do workby weak wind power to drive the gaits of multiplelegs through a transformation of internal cyclicmotion to an elliptical orbit of the legs [3].

Figure.3 A prototype of the extended Theo Jansenmechanism made of bamboo sticks

2.3 Use of Klann mechanism in underwater autonomouswalking robots



A low-cost, biologically inspired underwater walking robothas been designed and built to covertly explore the seabedand to determine properties of submerged objects in obscureand inaccessible underwater locations. Adopting leggedlocomotion for traversing the seabed has a number ofoperational advantages; firstly, the platform can maintain itsposition without expending energy; secondly, the typicallyunstructured terrain of the sea bed can be scaled efficiently;and thirdly, movement generates a low acoustic signaturewhich, for applications such as mine clearance or littoralWarfare would be beneficial.The design of the robotic platform, hereafter referred to asMechaLobster measures 170x550x260mm and is composedof; a watertight, negatively buoyant controller and batteryhousing (Otter Box); two modified drill motors (1:148gearbox) driving the Klann linkage6 inspired legmechanism[4].

Figure. 4. Photo of machalobster showing detail of whisker attachmentIII. Construction and working

It consist of motor or engine mounted at the top. Out of three spur gear one is connected to motor or

engine shaft called Driving gear and remainingtwo are meshes with driving gear with the help ofchain..

The crank is connected to the shaft on which twodriven gears are mounted.

As the motor made to ON the driving gear drivesanother two gear , one is clockwise while other isanticlockwise as the gears are rotate in oppositedirection.

Due to this this rotation resulting in the crankrotation.

Crank moves the forcing link gives the momentumin a particular line of action with help of supportinglink.

The work of supporting link is to move the arm in aparticular profile which made by the end point ofarm and move back to its normal position i.e. initialposition.

All these gives the walking motion to the arm likea spider.

SpcificationsSr.No. Component Quantity Specification

1. Motor 1 0.5HP(horsepower)2. Spur gear 3 Low carbon steel14C63. Arm linkage 8 Low carbon steel30C84. Crank 8 Low carbon steel30C85. Supportinglink 16

Low carbon steel30C8

6. Arm 8 Low carbon steel30C87. Forcing link 8 Low carbon steel30C88. Chain 1 High carbon steel55C8

Table I Components of mechanical spider by using klann mechanism

IV. Klann linkage for the project

Figure 5. Dimensions of klann linkage.

The Klann linkage is a planar mechanism designed tosimulate the gait of legged animal and function as a wheelreplacement. The Klann linkage was developed by JoeKlann in 1994 as an expansion of Burmester curves whichare used to develop four-bar double-rocker linkages such asharbor crane booms. It has been a hobby for a number ofyears to develop a bicycle without wheels that could walk. Itwould move on legs and resemble a large insect. A linkagewas developed that satisfied the design criteria and several











































small-scale prototypes were built that demonstrated theconcept. Applications for the linkage go beyond human-powered machines. The links are connected by pivot jointsand convert the rotating motion of the crank into themovement of a foot similar to that of an animal walking.

The Klann linkage provides many of the benefitsof more advanced walking vehicles without some of theirlimitations. It can step over curbs, climb stairs, or travel intoareas that are currently not accessible with wheels but donot require microprocessor control or multitudes ofinefficient actuator mechanisms. It fits into thetechnological void between these walking devices and axel-driven wheels.

V. Applications

1. Toys could be developed that would fit in the palm ofyour hand and just large enough to carry a battery and asmall motor. So that it could ride into combat with radio-controlled assault spiderbikes.2. The military, law enforcement, Explosive OrdinanceDisposal units, and private security firms could also benefitfrom applications of the spiderbike. It would perform verywell as a platform with the ability to handle stairs and otherobstacles to wheeled or tracked vehicles.

Figure 6. Explosive tracking spider bike3. Unmanned operations could be used for reconnaissance,patrolling, hazardous material handling, clearing minefields,or secure an area without putting anyone at risk.4 .There would be further benefits if a portion of these taskscould be automated or made more accurate through GlobalPositioning Systems, infrared viewing, and audio and videorecording. It could be programmed to patrol a predefinedperimeter at random intervals.

VI. ConclusionThis project can step over curbs, climb stairs, or travel intoareas that are currently not accessible with wheels but doesnot require microprocessor control or multitudes of actuatormechanisms.It would be difficult to compete with the efficiency of awheel on smooth hard surfaces but as conditions increase

rolling friction, this linkage becomes more viable andwheels of similar size cannot handle obstacles that thislinkage is capable of.Pivoting suspension arms could be used to optimize

The height of the legs for the waterline. Increase the platform height. Reduce the vehicle width.

Also it allows the legs to fold up compactly for storage anddelivery.

REFERENCES[1] Design and prototype of a six-legged walking insectrobot Servet Soyguder and Hasan Alli MechanicalEngineering Department, Firat University, Elazig, TurkeyIndustrial Robot: An International Journal Volume 34 Number 5 2007 412422[2] Mechanical Design of A Quadruped Robot forHorizontal Ground to Vertical Wall Movement AbdAlsalam Sh. I. Alsalameh Shamsudin H.M. Amin RosbiMamat Center for Artificial Intelligence and Robotics(CAIRO) Faculty of Electrical EngineeringUniversiti Teknologi Malaysia[3] A study of availability and extensibility of Theo Jansenmechanism toward climbing over bumps Kazuma Komoda(PY)1, and Hiroaki Wagatsuma 1 Department of BrainScience and Engineering, Kyushu Institute of Technology2 RIKEN Brain Science Institute[4] Artificial active whiskers for guiding underwaterautonomous walking robots T. Rooney_, M.J.Pearson, J.Welsby, I. Horsfield, R. Sewell, S. Dogramadzi BristolRobotics Laboratory, University of the West of England,Bristol, BS161QD, UK





V. Applications












V. Applications








Documents

Mechanical Spider