Hexapod robot ppt

1
PRESENTATION ON MECHANICAL SPIDER
2
CONCEPT

• It is based on Kinematics Of Machine.
• Quick return Mechanism.
• Four Bar Mechanism.

3

• Before starting the Project we need to
  understand the concepts of Kinematics and
  Dynamics.
• Kinematics of mechanisms is concerned with the
  motion of the parts without considering how the
  influencing factors (force and mass) affect the
  motion. Therefore, kinematics deals with the
  fundamental concepts.
• Kinetics deals with action of forces on bodies.
• Dynamics is the combination of kinematics and
  kinetics.
• Dynamics of mechanisms concerns the forces that
  act on the parts -- both balanced and unbalanced
  forces, taking into account the masses and
  accelerations of the parts as well as the
  external forces.

4
TERMINOLOGY

• There are four basic terms in KOM.
• Links
• Pair
• Joints
• Degree of Freedom

5
Types of Link
Kinematic Link

• Each part of a machine, which moves relative to
  some other part, is known as a kinematic link (or
  simply link) or element.

• Rigid link.
• A rigid link is one which does not undergo any
  deformation while transmitting motion. Strictly
  speaking, rigid links do not exist. However, as
  the deformation of a connecting rod, crank etc.
  of a reciprocating steam engine is not
  appreciable, they can be considered as rigid
  links.
• Flexible link.
• A flexible link is one which is partly deformed
  in a manner not to affect the transmission of
  motion. For example, belts, ropes, chains and
  wires are flexible links and transmit tensile
  forces only.
• Fluid link.
• A fluid link is one which is formed by having a
  fluid in a receptacle and the motion is
  transmitted through the fluid by pressure or
  compression only, as in the case of hydraulic
  presses, jacks and brakes.

6
Kinematic Pair

• The two links or elements of a machine, when in
  contact with each other, are said to form a pair.
  If the relative motion between them is completely
  or successfully constrained (i.e. in a definite
  direction), the pair is known as kinematic pair.
• Types of Kinematic PairLower
  pair
• When the two elements of a pair have a surface
  contact when relative motion takes place and the
  surface of one element slides over the surface of
  the other, the pair formed is known as lower
  pair. It will be seen that sliding pairs, turning
  pairs and screw pairs form lower pairs.
• Higher pair
• When the two elements of a pair have a line or
  point contact when relative motion takes place
  and the motion between the two elements is partly
  turning and partly sliding, then the pair is
  known as higher pair.

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DEGREE OF FREEDOM

• It is the number of inputs (number of independent
  coordinates) required to describe the
  configuration or position of all the links of the
  mechanism, with respect to the fixed link at any
  given instant.
• Grublers equation
• n DOF
• l No. of links
• j No. of lower pair
• h No. of Higher pair

8
QUICK RETURN MECHANISM

• A quick return mechanism such as the one seen
  below is used where there is a need to convert
  rotary motion into reciprocating motion. As the
  disc rotates the black slide moves forwards and
  backwards. Many machines have this type of
  mechanism and in the school workshop the best
  example is the shaping machine.

9
PROJECT DESCRIPTION

• Aluminum material is used as its body.
• Six legs.
• Six links.
• 2 DC geared motor.
• 2 Crank.
• Wooden Block.
• 9-12V battery.
• Nuts and bolts

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PROJECT PROTOTYPE
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MID LEG MECHANISM
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FINAL PROTOTYPE