DESIGN AND ARRANGEMENT DESIGN AND ARRANGEMENT OF DISPLAYS AND CONTROLS OF DISPLAYS AND CONTROLS

SITI ZAWIAH MD DAWAL SITI ZAWIAH MD DAWAL DEPT OF ENG. DESIGN AND DEPT OF ENG. DESIGN AND

MANUFACTUREMANUFACTUREUNIVERSITY OF MALAYAUNIVERSITY OF MALAYA

Displays and controls are the interface Displays and controls are the interface through which human-machine information through which human-machine information exchange takes place.exchange takes place.

The design of the displays and controls of The design of the displays and controls of a machine can either facilitate interaction a machine can either facilitate interaction or increase task difficulty and the or increase task difficulty and the probability of error. probability of error.

CONTROLSCONTROLS

Controls transmit input to a piece of Controls transmit input to a piece of equipment.equipment.

Usually operated by hand or foot.Usually operated by hand or foot.

The results of the control inputs are shown The results of the control inputs are shown to the operator either in terms of displays to the operator either in terms of displays or indicators or by the ensuring actions of or indicators or by the ensuring actions of the machine.the machine.

DESIGN OF CONTROLSDESIGN OF CONTROLS

Controls should be designed to be Controls should be designed to be operable in low-stress postures and operable in low-stress postures and without static loading of body parts, particu without static loading of body parts, particu larly the fingers. larly the fingers.

Control dimensions should be determined Control dimensions should be determined using appropriate hand and foot using appropriate hand and foot anthropometry and a knowledge of the anthropometry and a knowledge of the mechanical advantage needed to enable mechanical advantage needed to enable the user to actuate the control easily.the user to actuate the control easily.

Vehicle ControlsVehicle Controls

Steering wheels, joy sticks, and pedals are Steering wheels, joy sticks, and pedals are commonly used to control vehicles. Control commonly used to control vehicles. Control usability can be affected by the resistance of the usability can be affected by the resistance of the control, which should be operable using forces control, which should be operable using forces which are a fraction of the operator's maximum which are a fraction of the operator's maximum voluntary contraction. voluntary contraction.

However, the control should offer some However, the control should offer some resistance to movement so that bumping errors resistance to movement so that bumping errors and muscle tremor do not cause control errors and muscle tremor do not cause control errors (Young, 1973).(Young, 1973).

Control DistinctivenessControl Distinctiveness

In many instances, numerous controls are In many instances, numerous controls are grouped together on a panel and the grouped together on a panel and the designer's task is to ensure that operators designer's task is to ensure that operators can easily distinguish between different can easily distinguish between different controls. In addition, manual controls controls. In addition, manual controls provide the operator with tactile feedback provide the operator with tactile feedback which can be used to give a distinctive which can be used to give a distinctive identity to a control or related set of identity to a control or related set of controls.controls.

McCormick and Sanders (1982) McCormick and Sanders (1982) recommend using several dimensions to recommend using several dimensions to code different controls so as to enhance code different controls so as to enhance their distinctiveness. Designers may their distinctiveness. Designers may choose from shape, color, texture, size, choose from shape, color, texture, size, location, operational method, position, and location, operational method, position, and labeling. labeling.

Voice Control: Problems and Voice Control: Problems and prospectsprospects

The development of speech-recognition The development of speech-recognition technology introduces the possibility of using technology introduces the possibility of using voice as a control device. Some potential voice as a control device. Some potential advantages of voice control are the following:advantages of voice control are the following:

1. It provides an extra communication channel 1. It provides an extra communication channel which may take some of the load offwhich may take some of the load offmore conventional channels.more conventional channels.

2. It frees the hands to carry out other activities. 2. It frees the hands to carry out other activities. 3.3. Subroutines are already built up for the Subroutines are already built up for the

production of voice commands, so training time production of voice commands, so training time should be reduced.should be reduced.

The processing requirements for issuing The processing requirements for issuing voice commands would not be expected to voice commands would not be expected to conflict with those for manual control; conflict with those for manual control; therefore voice is often thought to have the therefore voice is often thought to have the potential to speed up task performance or potential to speed up task performance or increase an operator's information-increase an operator's information-handling capacity. handling capacity.

Some evidence for this comes from Martin and Some evidence for this comes from Martin and Long (1984), who investigated a simulation of a Long (1984), who investigated a simulation of a ship's gunfire control task which involved ship's gunfire control task which involved compensatory tracking as a primary task. They compensatory tracking as a primary task. They found that a simultaneous pointing task found that a simultaneous pointing task degraded tracking performance, whereas a degraded tracking performance, whereas a spoken version of the same task did not. It was spoken version of the same task did not. It was concluded that the findings were consistent with concluded that the findings were consistent with a multichannel model of performance in which a multichannel model of performance in which speech and tracking occupied parallel, but speech and tracking occupied parallel, but independent, channels with no common capacity independent, channels with no common capacity limitation.limitation.

Voice Recognizer FacesVoice Recognizer Faces

Speech is a complex acoustic signal containing Speech is a complex acoustic signal containing bands of energy centered on 500, 1500, 2000, bands of energy centered on 500, 1500, 2000, and 3000 Hz. These are known as formants and and 3000 Hz. These are known as formants and they consist of an initial transient segment they consist of an initial transient segment followed by a steady-state segment. The lower followed by a steady-state segment. The lower two formants are sufficient for the perception of two formants are sufficient for the perception of speech, which enables bandwidth compression speech, which enables bandwidth compression to be implemented to reduce the information to be implemented to reduce the information load of speech transmission systems and load of speech transmission systems and speech synthesizers.speech synthesizers.

Many investigations of speech perception Many investigations of speech perception by humans have been carried out by by humans have been carried out by researchers in the field of researchers in the field of psycholinguistics (see Howard, 1983, for psycholinguistics (see Howard, 1983, for an introduction to this research). Speech an introduction to this research). Speech perception is thought to depend on the perception is thought to depend on the interplay of both top-down and bottom-up interplay of both top-down and bottom-up processes. Bottom-up (analytic) processes processes. Bottom-up (analytic) processes detect particular features in the speech detect particular features in the speech signal as it is received. signal as it is received.

Combinations of features detected in speech Combinations of features detected in speech form the characteristic signatures of basic form the characteristic signatures of basic speech sounds such as phonemes, syllables, or speech sounds such as phonemes, syllables, or words. When matched with a stored words. When matched with a stored representation of known features, the speech representation of known features, the speech can be said to have been recognized. Top-down can be said to have been recognized. Top-down (synthetic) processes use higher-order (synthetic) processes use higher-order information to synthesize possible items which information to synthesize possible items which can be matched against the incoming signal can be matched against the incoming signal (trying to "guess what's coming next"). A (trying to "guess what's coming next"). A knowledge of grammar, syntax, and context is knowledge of grammar, syntax, and context is required to drive these higher order interpretive required to drive these higher order interpretive processes.processes.

DISPLAYSDISPLAYS

Display provide operator with information Display provide operator with information about the status of equipment.about the status of equipment.

Displays are either visual, auditory, tactile.Displays are either visual, auditory, tactile.

Labels and instructions or warnings are Labels and instructions or warnings are special kind of displays.special kind of displays.

Selecting the displaySelecting the display

Status informationStatus information

Historical informationHistorical information

Predictive informationPredictive information

Instructional informationInstructional information

Commanding informationCommanding information

VISUAL DISPLAYVISUAL DISPLAY

Check displayCheck display

Qualitative displayQualitative display

Quantitative displayQuantitative display

SCALES AND POINTERS SCALES AND POINTERS

May be straight, curved or circularMay be straight, curved or circular

Should be simpleShould be simple

Numerals Numerals

CODINGCODING

LocationLocation

ShapeShape

SizeSize

Mode of operationMode of operation

LabelingLabeling

ColorColor

Combining control and Combining control and displaydisplay

Use Grouping Principle in Panel DesignUse Grouping Principle in Panel Design

Avoid Spatial Transformations Avoid Spatial Transformations

COMPUTER INPUT DEVICESCOMPUTER INPUT DEVICES

Numerical KeypadsNumerical Keypads

Computer keyboardsComputer keyboards

Other input devicesOther input devices

LABELSLABELS

It is necessary to use label to locate , It is necessary to use label to locate , identify, read or manipulate controls, identify, read or manipulate controls, displays or other equipment. Labeling displays or other equipment. Labeling must be done so that the information must be done so that the information provided accurately and rapidly. provided accurately and rapidly.

DESIGN OF LABELSDESIGN OF LABELS

Orientation –horizontal –easy to read Orientation –horizontal –easy to read Location – place near item it identifiesLocation – place near item it identifiesStandardization -consistentlyStandardization -consistentlyAbbreviation -commonAbbreviation -commonBrevity –concise as possible –intended Brevity –concise as possible –intended meaningmeaningFamiliarity –words familiarFamiliarity –words familiarVisibility and Legibility – can be read easily –Visibility and Legibility – can be read easily –under worst illumination, vibration…etcunder worst illumination, vibration…etcFont and size – should be simple - readFont and size – should be simple - read

WARNINGSWARNINGS

Reasons to warn – potential injury, dangerReasons to warn – potential injury, danger

What to warn about – people must be warn What to warn about – people must be warn about various concerns –e.g product must about various concerns –e.g product must be used properly..be used properly..

Whom to warn – product manufacturer has Whom to warn – product manufacturer has the duty to warn –potential user, customer, the duty to warn –potential user, customer, sales marketingsales marketing

How to warn –on product itself, advertizing How to warn –on product itself, advertizing sales instructions to customers/ userssales instructions to customers/ users

DESIGN OF WARNINGSDESIGN OF WARNINGS

Visual warning –may contain text, graphics Visual warning –may contain text, graphics pictures – often redundantpictures – often redundant

Symbol and Icons –meant to identify Symbol and Icons –meant to identify object , warn of hazard or indicate an object , warn of hazard or indicate an action.action.