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TITLE NAME :

TITLE NAME :-


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D.SUDHEER 07731A0354

B.MANOHAR 07731A0333

K.L PRASANNA 07731A0340

N.SREETEJA 07731A0352

P.MAHESH 07731A0330

PRESENTED BY :


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The six legs are arranged into pairs and

each pair of legs is supported and actuated by afour-bar mechanism

INTRODUCTION

The six legged walker purpose is amechanical structure with linkages driver by anelectrical motor. The control of the driver is byan electrical lead wire with an option forupgrading to remote control


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THE SCOPE OF THE PROJECT IS :

1. Design of kinematics.

2. Design of individual structural member.3. Design / scission of the motor & driver.

4. Design of drive element.

5. Assembly of the walker.

6. Testing of the walker.


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1. Two-legged walker.

2. Four-legged walker.

3. Six-legged walker.

4. Walker with over six legs.

TYPES OFWALKERS


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The first phase of the design was selection of

design requirements. Some of the key

objectives of the design were :

- Low weight

- Low cost

- Low maintenance

- Short fabrication time

- Simplicity

- Functionality.

MECHANICS


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*Four bar linkages are most preferred machine

Components.

* The design techniques become simpler if

one or more slider joints are included in the

mechanisms.

FOURBARLINKAGE


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*The exact desired motion is very rare to be

produced by using four bar linkages.

*Four-bars are simple mechanisms common in

mechanical engineering machine design andfall under the study of kinematics.

*Four-bar linkages perform a wide variety ofmotions with a few simple parts.


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A four bar linkage or simply a 4-bar or four-bar

is the simplest movable linkage. It consists of 4

rigid bodies (called bars or links), each attached

to two others by single joints or pivots to form a

closed loop.


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DEGREES OFFREEDOM

Translational motions along any three mutuallyperpendicular axes X,Y and Z.

Rotational motions about these axes.

Thus a rigid body possesses 6 degrees of freedom.The number of restraints can never be Zero(joint isdisconnected) or six (joint becomes solid)

Degrees of freedom of a pair is defined as thenumber of independent relative motions, bothtranslational and rotational, a pair can have

Degrees of freedom= 6 - (number of restraints)


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Kutzbach-Gruebler's equation is used to

calculate the degrees of freedom of linkages.

*A simplified version of the Kutzbach-Gruebler's

equation for planar linkages :

m=3(n-1)-2f

m =mobility = degrees of freedom.

n= number of links (including a single groundlink).

f= number of one-degree-of-freedom kinematic

pairs (pin or slider joints).


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Grashof's law is applied to pinned linkages and

states; The sum of the shortest and longest link of

a planar four bar linkage cannot be greater thanthe sum of remaining two links if there is to be

continuous relative motion between the links.

Below are the possible types of pinned, four-bar

linkages;


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Inversions of a Four-Bar Mechanism

This mechanism can have four possibleconfigurations with a different link fixed asframe each time.

Configuration 1:-

*Link 1 is taken as thebase link or frame

*In this configuration the shortest link isjointed to the base link and this joint canfully rotate and hence called as crank.


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Configuration 2:-

* Link 2 is fixed as the base link.

* In this configuration shortestlink is the base and both joints to

the base can rotate Completely.

Configuration 3:-

* Link 3 is fixed as the base

link*It can be observed that this

configuration is same as the

Crank-Rocker mechanism.


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Configuration 4:-

*Link 4 is fixed as the base link.

*In this configuration shortest link is the

coupler and both the links connected to the

base link cannot rotate fully, both oscillate. In

this configuration the four-bar kinematic chainis called as Double-Rocker mechanism


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