Cylindrical Co-ordinate Robots

1
Cylindrical Co-ordinate Robots

• Mechatronics Case Study

2
Overview

• Overview of Robot Functionality
• Draw Comparisons with Bradley Diagram
• Detailed Description of Device Intelligence
• Compare Wholly Mechanical / Electro-mechanical
  System

3

• 3 Axis Robot

• Vertical Movement, Radial Distance ?

4

• 350o Motion about the Centre
• Radius Of 500mm (Limited to Arm Extension)
• 750mm Vertical Extension
• Design Loads Up-to 125g, 300mm Dia. Disk

5
Simplified Data / Process Flow Diagram
PC
Dedicated Control Unit
Robot
6
Bradley Diagram (1)

• Assembly Module
• Stainless steel curved plate shell
• Top plate and base unit
• Cage chassis that rotates within shell
• Lead screw for z-axis
• Belts for r and theta axes
• Fans to extract dirty air

• Environment Module
• Class 1 cleanroom
• Atmospheric pressure
• Room temperature
• Low humidity
• Payload
• Thin disc
• 300mm diameter
• 125g in mass

7
Bradley Diagram (2)

• Measurement Module
• Laser mapper to scan cassettes of wafers

• Communications Module
• Mapper emits digital high when wafer sensed
• Pressure sensor emits digital high above a
  specified pressure
• Encoders transmit binary code to specify absolute
  position

• Pressure sensor to sense whether payload is
  present
• Encoders to feedback position of three axes of
  motion

8
Bradley Diagram (3)

• Software Module
• Programmed in a high level language
• Code written in macros that can be combined to
  create movements
• Code compiled into machine code
• Can control individual I/O or macros

• Processor Module
• Separate Control Unit
• Heart is a full CPU on a motherboard
• CPU communicates with
• Motion control board
• I/O board
• Safety circuit
• Amplifiers

9
Bradley Diagram (4)

• Interface Module
• Controlled using separate standard PC
• Operated using specific control program
• Use buttons to select moves or I/O
• Or can use simple communication program
• Send ASCII commands and receive 4-bit binary
  responses

• Actuation Module
• Separate motors for three axes of motion
• Uses brushless DC motors
• Controlled by changing supplied voltage
• Payload gripped by activating / deactivating
  in-line pressure sensor

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Intelligence and PerformanceImprovements Robot

• Belt Drive ? Direct Drive
• Improves
• Accuracy
• Sensitivity
• Reliability
• Steel Cage ? Aluminium backbone
• Improves
• Rigidity
• Accuracy

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Intelligence and PerformanceImprovements
Controller

• Automated Calibration
• Calibration previously carried out manually
• Environment co-ordinate file stored on controller
• Robot touch-senses to find R- T-axes
• Mapper used to sense Z-axis
• Enables 1-touch calibration
• Cannot be achieved on older systems due to belt
  drive and controller capability

12
Intelligence and PerformanceImprovements
Controller

• Advanced Motion
• Control of multiple axes
• PTP motion
• Optimised trajectories and motion profiles
• Health Monitoring
• Fingerprinting motor characteristics
• Comparing current data to fingerprint to predict
  failure

13
Intelligence and PerformanceImprovements
Controller

• Distributed Control
• Previously, intelligence at host level devices
  considered as dumb actuators
• In modern systems, responsibility placed with
  individual devices
• Enables a task-oriented approach
• More flexible can control multiple devices

14
Conclusion

• Electro-mechanical
• Open Loops No Feedback
• Large Human Input (Gross Intervention Always
  Needed To Operate GIANTO)
• Requires Regular Calibration
• Inflexible Modifications

15
Conclusion (2)

• Mechatronic
• Current Mechatronic
• Closed Loop Feedback
• Little human Intervention (Diminished Want of
  Actual Robot Functional Intervention DWARFI)
• Flexible Programming
• Advanced Mechatronic
• No Human Intervention
• Fully Contained System
• Ease Of Customisation