robot leg mechanism.ppt

• PRESENTED BY -

CHOUDHARY SUMIT AJAY

“ROBOT LEG MECHANISM”

A SEMINAR

PRESENTATION ON

COMPONENTS OF ROBOT LEG

Structure

Power source

ActuationMobility

Sensing

STRUCTURE(KINEMATIC CHAIN)

LINKS(BONES)

ACTUATORS(MUSCLES)

POWER SOURCE

POWER SUPPLY

A.C. D.C. SOLAR

TYPES OF ACTUATORS

Electrical

Hydraulic

Pneumatic

Others

ELECTRICAL ACTUATORS

The types of Actuators we use in Robotics are:AC motorsDC motorsDC geared motorsStepper motorsServo motors

TYPES OF SENSORS

• IR SENSOR

• SOUND SENSOR

• TEMPERATURE SENSOR

PID CONTROL SYSTEM

Proportional-integral-derivative (PID) control

Is control loop feedback mechanism

Controller minimizes the error

three-term control: P I D

PID equation

Kp – Proportional GainKi – Integral GainKd- Derivative Gain

LOCOMOTION

DOF

TRANSATIONAL

ROLL,PITCH,YAW

ROTATION

X,Y,Z

TYPES OF LOCOMOTION MECHANISM

loco

mo

tio

nwheeled

crawler

legged

Robot leg

STABILITY

STABILITY

STATIC

(mech. design)DYNAMIC

(control)

STABILITY OF A ROBOT

STABILITY

BIPED

CG

ZMP

QUADRUPPED CG

where x.... , y.... and ..z.. are linear

accelerations, Iix and Iiy , are inertia

coefficients, aix and aiy are

angular accelerations, mi is the mass of the link

i, and g is the gravitational acceleration

DETERMINATION OF ZMP

Biped lumped mass model.

The ZMP is defined as the point on the ground where the sum of all the active moments of force is null.

Minimum distance between the ZMP and the border of the stable region is called the stability margin

This can be considered as an indicator of the quality of the robot’s stability.

CHARACTERISTICS OF HUMANOIDS

• Self-maintenance

• Autonomous learning

• Avoiding harmful situations to people, property, and itself

• Safe interacting with human beings and the environment

• Legged locomotion

• Arm control and dexterous manipulation

LEG-WHEEL HYBRID ROBOTS

• • The Mini-Andros is used

• by bomb squads across

• the country to locate and

• dispose of bombs. About

• three feet long, the Mini-

• Andros looks something

• like a small armoured

• tank with eight wheels on

• four "legs" that extend

• for climbing stairs.

Shrimp (EPFL)

a) Biped leg-wheel robot (1998) b) Roller Walker (1996)

c) RHex (2001) d) Whegs II (2003)

Leg–wheel hybrid robots

Disadvantages Advantages

APPLICATION OF

HUMANOIDS

SPACE

MEDICAL SCIENCE

WARFRONTS

INDUSTRIES

Prosthetics Inspection of

dangerous environments

Entertainment Agricultural work

APPLICATIONS

Q

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