Automated Precision Machines

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Automated Precision Machines

• Team 2
• Nicholas Neumann
• Ralph Prewett
• Jonathan Brouker
• Li Tian
• Felix Adisaputra
• November 5th, 2010

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Contents

• Servo Motor
• Stepper Motor
• Sensors for Precision Control
• Robotic Programming Languages
• Automated Machines

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What is a Servo Motor?

• Closed-Loop System
• Precise position control

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Servo Motor

• Servo Mechanism
• 1 Position Sensor
• 2 Electric Motor
• 3 Reduction Gears

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Servo Motor

• Closed-Loop System

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Servo Motor

• Example
• No Control
• No Feedbacks

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Servo Motor

• Proportional-Integral-Derivative Control
• Overshoot 0
• Rise Time
• Settling Time
• Steady-State Error 0

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Servo Motor

• Applications
• Labelling
• Machine

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Stepper Motor

• Brushless, Synchronous Electric Motor
• Open-Loop System
• (No Feedback)
• Full Rotation Divided into
• Large Number of Steps
• Torque Decreases as Speed Increases.

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Stepper Motor

• Permanent Magnet Stepper Motor

• Tin-Can or Canstock
• Low Cost
• Low Resolution
• 7.5o to 15o step angles
• 48-24 steps/revolution
• Rotor Magnetized with Alternating Poles
• More Magnetic Flux Provides More Torque

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Stepper Motor

• Hybrid Stepper Motor
• More Expensive
• Better Performance
• Torque
• Speed
• Higher Resolution
• 3.6o to 0.9o step angles
• 100-400 steps/revolution
• Rotor
• Multi-Toothed
• Axially Magnetized Concentric Magnet

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Stepper Motor

• Two-Phase Stepper Motor
• Bipolar Drive
• Single Winding per Phase
• Half the Power Loss
• Unipolar Drive
• Two Windings per Phase
• One for Each Magnetic Field Direction
• Fewer Switches

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Stepper Motor

• Applications
• Film-Advance

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Stepper Motor

• Applications
• Conveyor

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Servo Motor vs Stepper Motor
Servo Motor Stepper Motor
Drive Circuit Complicated. Difficult for user to fabricate it. Simple. User can fabricate it.
Noise and Vibration Very little Significant
Speed Faster (3000-5000rpm max.) Slow (1000-2000rpm max.)
Out-of-Step Condition Not Possible (Heavy load Still Run) Possible (Heavy load Stop)
Control Method Closed-Loop (uses an encoder) Open-Loop (no encoder)
Resolution ppr pulses per revolution 0.36 (1,000 ppr) to 0.036 (10,000 ppr) 2-phase PM model 7.5 (48 ppr) 2-phase HB model 1.8 (200 ppr) or 0.9 (400 ppr) 5-phase HB model 0.72 (500 ppr) or 0.36 (1,000 ppr)
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Sensors for Precision Control

• Hall Effect Sensor
• Voltage Transducer
• Response to Changes in
• Magnetic Field
• Applications
• Switching, Positioning, Speed Detection, Current
  Sensing

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Sensors for Precision Control

• Advantage
• They are immune to dirt, dust and water,
• They are capable of switching at high
  frequencies.
• They can be used for a wide variety of
  applications.

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Sensors for Precision Control

• Rotary Potentiometer
• Position Transducer
• Three-Terminal Resistor
• Adjustable Voltage Divider

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Sensors for Precision Control

• Potentiometer

If RL gtgt (R1 and R2),
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Sensors for Precision Control

• Linear Potentiometer
• Displacement Transducer
• Voltage Division
• Hybrid Conductive Film

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Sensors for Precision Control

• Rotary Encoder
• Electromechanical Device
• Angle Transducer
• Angular Position
• Analog/Digital Code
• Types
• Absolute Rotary Encoder
• Incremental Rotary Encoder

Gray Code
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Sensors for Precision Control

• Rotary Encoder
• Gray Code

Sector Contact 1 Contact 2 Contact 3 Angle
1 off off off 0 to 45
2 off off ON 45 to 90
3 off ON ON 90 to 135
4 off ON off 135 to 180
5 ON ON off 180 to 225
6 ON ON ON 225 to 270
7 ON off ON 270 to 315
8 ON off off 315 to 360
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Robotic Programming Languages

• C Language
• Pros
• Speed of Resulting Application
• Application in Firmware
• Programming
• Compatible with Many Other
• Languages
• Code is Compacted into
• Executable Instruction
• Cons
• No Runtime Checking
• No Strict Type Checking
• Can Pass Integer Value for Floating Data Type
• Very Difficult to Fix Bugs as Program Extends

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Robotic Programming Languages

• RobotC Language
• Pros
• More Functions than Regular Graphical Language
• Easy to Navigate Through Program
• Suitable for More Complicated Programs
• Cons
• Text-Based Language
• Hard for Beginners
• Must be Bought Separately
• from Kit

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Robotic Programming Languages

• Ladder Logic
• Pros
• Familiar Programming Language
• Relay Logic (Widely Used)
• Cost-Effective Equipment
• Reliable Parts
• Simple Circuits
• Cons
• Difficult Integration with Third Party Software

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Robotic Programming Languages

• BASIC
• Pros
• User Friendly and Interactive
• Simple and Easy
• Rapid Development
• Powerful Front-End Tool
• Multiple Vendor Support
• Cons
• Memory Leakage
• Passing Value by Reference
• Only for Windows
• Sluggish Performance

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Robotic Programming Languages

• LabVIEW
• Pros
• User Friendly Graphical Interface
• Universal Platform for Numerous
• Applications
• Compatible with Other Languages
• Execution Highlighting Feature
• Cons
• Expandability Problem
• Depends on How Well the Original Program was
  Written
• Memory Management
• Difficult Memory Allocation
• Expensive

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Robotic Programming Languages

• LEGO Mindstroms NXT
• Pros
• Icon-Based Drag and Drop
• Graphical Language
• Easy Maintenance
• Simple Programs
• Cons
• Lack of Complex Features in the Compiler

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Robotic Programming Languages

• Which Language to pick?
• Previous Experience
• How much time and effort you intend to invest
• Your goals
• Availability

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Automated Machines

• Control Systems
• Information Technologies
• Reduce Human Work

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Automated Machines

• Programmable Logic Controller (PLC)
• Digital Computer
• Automation of Electromechanical Processes
• Multiple Input-Output Arrangements
• Armored for Severe Conditions
• User Interface

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Automated Machines

• Supervisory Control and Data Acquisition (SCADA)

• Centralized Systems
• Monitor and Control
• Human-Machine Interface (HMI)
• Alarm Conditions

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Automated Machines

• Main Advantages
• Replacing Human Operators in Monotonous Work
• Performing Tasks that are Beyond Human
  Capabilities
• Size, Weight, Speed
• Dangerous Environment
• Space, Underwater, Nuclear Facilities
• Economy Improvement

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Automated Machines

• Main Disadvantages
• Technology Limits
• Unable to Automate All Desired Tasks
• High Initial Cost
• Unpredictable Development Costs

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Questions