A Design Method For Human-Friendly Man-Machine Systems

Eri ItohResearch Fellow of Japan Society

for the Promotion of Science, Department of Aeronautics and Astronautics,

University of Tokyo

1. Introduction

2. Manual control experiments

3. New method

for estimating workload levels 4. Controller design

5. Conclusion

Contents 1/26

1-a. Introduction 2/26

To realize human-friendly piloting,man-machine systems should

reduce workload levels.

Background

Both the physical and the mental loadin the course of carrying out the task.

1-b. Introduction 3/26

Past work in workload estimation

1. Handling qualities criteria

2. Subjective rating

3. Physiological response

1-c. Introduction 4/26

Conventional methodsdon’t quantitatively define workload.

They are difficult to utilize as conceptual design condition

of flight controller.

1-d. Introduction 5/26

Purposes

1. To propose a new method to quantitatively estimate WL levels .

2. To use the method, to design flight controller which guarantee human-friendly operation.

1-e. Introduction 6/26

To propose a method to estimate WL levels,this research relate pilot models to WL.

Transfer functions which represent pilot operation

1-f. Introduction 7/26

Review of past work in pilot models

In 1950’s to 70’s, pilots were modeled as low-order transfer functions.

Recent high-performance vehicles impose difficult operation to pilots.

Considering pilots as controllers,they have to have high-order dynamics.

1-g. Introduction 8/26

This research adopts high-order pilot models

2-block pilot models

Pilot models are identified by experiments.

2-a. Manual control experiments 9/26

Experimental apparatus

These Experiments are analogous to longitudinal dynamics of aircraft in the effect of disturbance input.

2-b. Manual control experiments 10/26

Experimental procedures

2-block pilot models were identified with high-order transfer functions.

WL level is commented by using a 5 point rating scale . 1 ・・・ The most comfortable piloting

5 ・・・ The most wearisome piloting

Block Diagram

2-c. Manual control experiments 11/26

Experimental results – Gain plots of pilot models

WL 1

WL 3 WL 5

2-d. Manual control experiments 12/26

Experimental results – Controllable Frequency

Controlled dynamics(operator not included)

Closed-loop systems(operator in the loop)

The limit of controllable frequency is 4rad/sec.

2-e. Manual control experiments 13/26

Summary of experimental results

1. There exist ideal gain plots shape for pilot models which correspond to comfortable piloting.

2. The gap between the ideal gain plots shape for pilot models and the other ones indicate the increase of WL levels.

3. The limit of controllable frequency for pilots is 4 rad/sec.

3-a. New method for estimating WL levels 14/26

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Gain Plots of pilot models

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Subject gain plots

Estimation Index 1 Estimation Index 2

Estimation Indices

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3-b. New method for estimating WL levels 15/26

The relation between WL comments and indices – H1

3-c. New method for estimating WL levels 16/26

The relation between WL comments and indices – H2

3-d. New method for estimating WL levels 17/26

　 H1 　　　　 H2 　　　 WL Level1 　 Level1 　　1 Level1 　 Level2 　　2 Level2 　 Level1 　　2 Level2 　 Level2 　　3 Level2 　 Level3 　　4 Level3 　 Level2 　　4 Level3 　 Level3 　　5

Estimation method

Subjective WL comments and estimated WL levelsagree to 95 %.

3-e. New method for estimating WL levels 18/26

Results achieved to date

This research proposes a method which quantitatively estimates workload levels

though pilot models.

The proposed method enables us to design controller

on assumed workload levels

4-a. Controller design 19/26

Design purposes

1. To ensure workload level 1.2. To realize both ideal tracking performance and disturbance rejection.

1.Pick out pilot models and controlled dynamics. H1, H2 ・・・ WL level 1 P ・・・ WL level 52. Controller design to achieve desired tracking performance and disturbance rejection.

4-b. Controller design 20/26

Design procedures

4-c. Controller design 21/26

What could be the desired performance? - Tracking performance

1. The droop, which means a drop in gain value from 0dB, becomes more than -5dB for low frequencies below

4 rad/sec.

2. The peak value of gain is less than 0dB.

4-d. Controller design 22/26

What could be the desired performance? - Disturbance rejection

3. The peak value of gain is less than -5dB.

4-e. Controller design 23/26

By using 　　　　 loop shaping technique,

flight controller is designed which satisfy these 3 conditions. 　　　　　

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Demonstration experiments were carried out:One with controller and another without controller.

4-f. Controller design 24/26

Pilot’s comments and the proposed method indicate designed flight controller worked well.

Effectiveness of Designed Controller

With controller: subjectively commented as WL 1

Without controller: subjectively commented as WL 5

4-g. Controller design 25/26

Tracking performance Disturbance rejection

Both of tracking performance and disturbance rejectionsatisfy 3 design conditions

5. Conclusion 26/26

1. The new method to quantitatively estimate workload levels was proposed.

2. Flight controller which ensure human-friendly operation is designed though the proposed estimation method.

3. Demonstration experiments showed the effectiveness of the designed

controller.

Thank you very much!

APPENDIX 1-1

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APPENDIX 1-2

APPENDIX 1-3

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APPENDIX 1-4

APPENDIX 2-1

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The end