Flexible Manufacturing Line with Multiple Robotic …telerobot.cs.tamu.edu/CMA/slides/Heping...

Robotics Laboratory Ingram School of Engineering

Bring Ideas Together

Flexible Manufacturing Line with Multiple Robotic Cells

Heping Chen [email protected]


Texas State University

1



OUTLINE

• Introduction

• Autonomous Robot Teaching

– POMDP based learning algorithm

• Performance Optimization

– Single cell optimization

– Multi cell Optimization

• Discussion

2



Trim and Final Assembly Line

3



Problems in Production Line

• When one work station fails, the production line has to be stopped

– Low efficiency

– High cost

• For complex manufacturing processes, is it possible to optimize the system performance?

– Single work station optimization?

– Multi work station optimization?

4



Proposed Solution

5

Station controller/Computer





Other devices



Problems

• Big part location errors – Can happen after a new batch is launched – Parts could come from different suppliers

• Typically manual teaching methods are used to adjust the parameters – Production line has to be stopped

• Installing additional sensors generates new problems – System upgrading cost – Maintenance issues – Sensor failure

6



#1 FMS #2 FMS #n FMS

MTS

SICK

Kinect

Off-L

ine to On-L

ine Teaching

Off-

Line t

o On-L

ine T

each

ing

FMS:Fixed Manufacturing Station MTS:Mobile Teaching Station

Online Transfer Learning Online Transfer Learning

Online

Learning

Online

LearningOnline

Learning

Failure Correction

7



Autonomous Robot Teaching

• Reducing the operational cost

• Sensor accuracy problem

• Calibration is difficult

• Noise

Target Hole Transmission

Part

Robot ToolMarker for

Tool Detection

8



Autonomous Robot Teaching

Autonomous

Industrial Mobile

Manipulator

Hole

Transmission Part Tool/Peg

ABB IRB 140

Industrial Camera

“Adult”Robot

PC

Controller IRC5 Robot

Controller“Child”IRB140

Workpiece

Tool & Peg

DALSA Industrial

Camera

Gigabit

Ethernet

Ethernet

9



POMDP

• Partial Observable Markov Decision Process

– State Transition is Uncertain

– Observation is uncertain

– State is partial observable

• Why POMDP?

– Using POMDP to estimate the underlying errors through executing actions and receiving observations

10



POMDP Method

• Belief State – Real state is unknown

– How to make decision?

– Assign a belief b over state S

– Update the belief state in each step

– Defining Value Functions

– Approximating Value Functions • Alpha Vector

11



OUTLINE

• Introduction

• Autonomous Robot Teaching – MDP based learning algorithm

– POMDP based learning algorithm

• Performance Optimization – Single work station optimization

– Multi work station optimization

• Discussion

12



Example: Single Stage Assembly

13



Assembly Process

14

How to tune the Assembly Parameters?

Parameters: search force, search radius, search speed, insertion force



Example: Multi-Stage Assembly

15



Problems

• Design of Experiment (DOE)

• Genetic Algorithm (GA)

• Genetic Algorithm (GA)+ANN

• Model Free

• Offline

• Manufacturing line has to be stopped

• Cannot deal with variations, including part location errors, part geometry errors and environmental errors.

Low Efficiency Low Accuracy

16



Single Work Station Optimization

• First Time Through (FTT) rate

17

• How to balance FTT rate and cycle time? – FTT rate is calculated statistically.

– Cycle time is recorded each assembly

– Modeling?

– Optimization methods? • FTT prediction? Cycle time estimation?



Multi Work Station Optimization

• FTT rate of the whole system

• Cycle time of the production line

18



Performance Optimization

• Performance optimization

– Knowledge transfer

• What can we transfer? How to transfer?

19

2

kx

2

ku

2

ke

2

kn

2

ky1

kx

1

ku

1

ke

1

kn

1

kyM

kx

M

ku

M

ke

M

kn

M

ky

Stage 1 Stage 2 Stage M

Multi-Stage Learning Methodology



Discussions

• Comments

– Robot teaching

– System optimization

• Interesting topics?

–

20

Flexible Manufacturing Line with Multiple Robotic …telerobot.cs.tamu.edu/CMA/slides/Heping...

Documents

Transcript of Flexible Manufacturing Line with Multiple Robotic …telerobot.cs.tamu.edu/CMA/slides/Heping...