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7/28/2019 mr course work

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TECHNICAL UNIVERSITY OF SOFIAFaculty of Mechanical Engineering

SCARA ROBORT ARM (DISASSEMPLY)

KADIR SEZER

Fac. No: 283210117

Supervisors:

Volodya Pashov

Ivo YANAKIEV

20122013 SOFIA


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BULGARIAN SCARA ROBOT

First of all l would like to give you some knowledgeabout scara robot.


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SCARA

Notation VRO

SCARA stands for SelectivelyCompliant Assembly Robot Arm

Similar to jointed-arm robot exceptthat vertical axes are used for shoulder

and elbow joints to be compliant inhorizontal direction for verticalinsertion tasks

SCARA robots have three R joints 1,

2, and 4, plus a P joint d3perpendicular to that plane of motion,to achieve a 3D workspace. Theseare common table-top assemblyrobots.


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Joint Drive Systems Electric

o Uses electric motors to actuate individual jointso Preferred drive system in today's robots

Hydraulico Uses hydraulic pistons and rotary vane actuatorso Noted for their high power and lift capacity

Pneumatico Typically limited to smaller robots and simple material transfer applications

Robot Control Systems Limited sequence control

pick-and-place operations using

mechanical stops to set positions Playback with point-to-point controlrecords work cycle as a

sequence of points, then plays back the sequence duringprogram execution

Playback with continuous path control greater memorycapacity and/or interpolation capability to execute paths (inaddition to points)

Intelligent control exhibits behavior that makes it seemintelligent, e.g., responds to sensor inputs, makes decisions,communicates with humans


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Robot Control System

Joint 1 Joint 2 Joint 3 Joint 4 Joint 5 Joint 6

Controller

& Program

CellSupervisor

Sensors Level 0

Level 1

Level 2


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Working Envelope


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Advantages:

high speed.height axis is rigid

large work area for floor spacemoderately easy to program.

Disadvantages:

limited applications.

2 ways to reach pointdifficult to program off-line


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Example

A robot performs a loading and unloadingoperation for a machine tool as follows:

o Robot pick up part from conveyor and loads into machine (Time=5.5 sec)o Machining cycle (automatic). (Time=33.0 sec)

o Robot retrieves part from machine and deposits to outgoing conveyor.

(Time=4.8 sec)

o Robot moves back to pickup position. (Time=1.7 sec)

Every 30 work parts, the cutting tools in the machine arechanged which takes 3.0 minutes. The uptimeefficiency of the robot is 97%; and the uptime efficiencyof the machine tool is 98% which rarely overlap.

Determine the hourly production rate.


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Solution

Tc = 5.5 + 33.0 + 4.8 + 1.7 = 45 sec/cycle

Tool change time Ttc = 180 sec/30 pc = 6 sec/pc

Robot uptime ER = 0.97, lost time = 0.03.

Machine tool uptime EM = 0.98, lost time = 0.02.

Total time = Tc + Ttc/30 = 45 + 6 = 51 sec = 0.85 min/pc

Rc = 60/0.85 = 70.59 pc/hr

Accounting for uptime efficiencies,

Rp = 70.59(1.0 - 0.03 - 0.02) = 67.06 pc/hr


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Disassemble first part

When we started to diassempley frst we did disassemplymotors


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1.1 1.2

1.1 This motor is return gripper around itself. And this is 12v DC motor.1.2 this motor turning robot arm left and right. This is a step-motor.Our robot have 3 step-motors. Two of them using on arm to directioncontrol left-right. And last one using on the gripper bar to control up down motion.


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CABLE OFF

There are two joint point here. One for gripper control, second for

step motor control. That point middle of robot arm this is controlling last arm left right

movement. This is first connection point. There is a output and a input here.

Output for step motor control. This input connecting to any driverto control all robot motion.


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Gear box off

Top of the gear box ,there is a step motor. When step motor start to turnthis gears controlling speed. And there is a interesting something hereas you see the picture there is a gear and gear cover both of them hasteeth but they are not fit each other gear smaller than cover. They usedthis gear box to make speed control.


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The gripper off

First we did cable off.And we did gripper off.And gripper have a dc motor inside to

pick and place objects.


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The gripper mounted bar off

As you see on the pictures we diddisassembly gripper bar from last link.


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THEMAIN PARTS OF SCARA ROBOT

BASE LINKS


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cable, motors and gripper mounted bar.


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The gripper The gear box


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THANKS FOR

ATTENTION

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