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Ergonomic aspects of automation in navigation bridges
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l-rgonomic aspects of automation in navigation bridges A. Lazet and P. L. Walraven Institute for Perception RVO-TNO, Soesterberg,The N~therlands
New ergonomic questions arise from the tendency towards increasing automation in maritime operations. Direct control of engines and rudder from the bridge promises improved ship control, provided that the operator can really exploit the technical improvements. To make such direct control most efficient, good ergonomic design is essential. A series of designs of navigation bridges is used to illustrate typical problems and situations. The building of full scale mock-ups of complete bridges is essential in order to handle the design as an integrated problem and to simulate the work situation. Such static mock-ups have been shown to be extremely useful in the discussion between builder, future user and adviser. An extension to dynamic simulation is necessary in order to study the actual work conditions in a new design.
With the growth of automation aboard ships, the task of the man is concentrated more and more upon the controlling functions. Consequently, a ship designer is increasingly confronted with design problems where the man-machine relationship involves the operator as controller. The desired increase of performance is achieved only if man's possibilities are put to their best use in this relationship. To obtain this, both man and the technical systems must be subjected to research. Knowledge must be gained about the ways in which they affect one another both in a favourable and in an unfavourable sense. In many cases a very advanced technical development does not live up to expectations because adaptation to human capabilities has been neglected. It is therefore important to consider the human perceptual and control capabilities when designing each particular system. The starting point for the research leading to a design is a proper statement of the requirements. Sometimes it occurs that there is a divergence of opinions among future users about what is actually needed to perform the task involved. If the requirements are not properly defined, the research has to start with defining them. The Institute for Perception has given the Royal Dutch Navy advice for different navigation bridges. The different designs of some of those bridges and the influence of automation will be discussed in this article.
66
AppliedErgonomics
June 1971
The bridge control of ships Ship handling without direct control of engines and rudder from the bridge has been practised for many years. It stems from the procedures used in sailing vessels. The most striking shortcoming in this control arrangement is the delay-factor and, more importantly, the possibility of error due to an inherently slow verbal system of passing and effecting orders. Up to now in most of the Royal Dutch Navy ships the helmsman is positioned in a closed wheelhouse 'below decks,' and the orders are passed from the bridge via microphone or voice pipe and by telegraph for engine orders. Each message must be repeated at least twice so that the information is doubly subject to error - once in transmitting, once in delivery. Between those orders, at the same time, three or four loud speakers are also blaring tactical instructions and signals. If the communication links can be reduced there clearly would be less delay and the risk of response error would be less. In the past little attention has been given to the arrangements of controls in relation to the user and most of the displays and controls are scattered about. The change to automation makes it more neccessary to centralise and integrate controls and displays in consoles. This brings these items to the user and practically eliminates the need for movement about the bridge. Normally it is expected that
bridge personnel stand while on bridge watch, but the use of integrated consoles will without a doubt place the bridge personnel firmly in seats. There is no specific ergonomic reason why personnel cannot be seated. The reason proposed against sitting down is that personnel would go to sleep. On the other hand, the seated operator tires less quickly. Furthermore, in rough weather it is easier to use controls in a sitting position than in a standing position. An investigation to determine the environmental factors affecting ship control showed that visibility must be given prime consideration. An ideal navigation bridge has 360 ° visibility, but most of the time the conventional design and placement of the bridge on many ships restricts visibility such that areas aft of the bridge are virtually blind. The use of closed-circuit television would improve visibility.
Fig 2 shows the mock-up of the van Speyk-class bridge. This is a redesign of the old bridge. The requirements are nearly the same as for the old bridge, but in this design we incorporate the ergonomic requirements. The central navigation position is also in the fore-front of the bridge behind the pelorus, but the instruments have been so arranged that all are at hand in the central position. The principal instruments have been mounted above the windows and are readable from each point of the bridge even from the wings. The large windows with panes sloping forward promote an excellent view. Inclination of panes of
In Canada one of the authors gained experience with the use of television (Lazet, 1968) to view the sections of the ship which have always been invisible from the bridge. It appeared that the co-operation of a helicopter and a submarine hunter becomes far more efficient if the ship commander can observe the touchdown and take-off of the helicopter by means of a monitor mounted on the bridge. The touchdown of a helicopter on a navigating ship requires quick and efficient teamwork with continuing course corrections. An interesting problem was whether the monitor should give the picture the commander would have seen if he could have looked straight backward or if he looked forward. In the latter case a considerable number of starboard/port errors might have occurred. Apparently the commander feels himself so much 'at his right place' on the bridge that his perception is not restricted to 'looking forward' only. Also, for general navigational purposes television offers many possibilities. The use of television-cameras high on the mast offers a far greater field of view than the bridge. Dead angles may be abolished by cameras mounted at high locations. In particular when manoeuvring in ports, mooring, bringing alongside etc an excellent view is necessary. It must be accepted that with future designs of navigation bridges the use of television must be taken into account from the beginning.
Fig 1
General view of the old destroyer bridge.
Development of bridge design In 1962 we started with the design of the navigation bridge of the van Speyk-class frigate. In order to gain some experience regarding the manipulations, the communication, and the time these actions consume on the bridge, some visits were made aboard destroyers which were built in 1954. Fig 1 depicts the old bridge. The whole design is overloaded with ergonomic mistakes. Visibility, the most important factor for navigating, is very poor, and the instruments are scattered around. The central navigating position is facing the pelorus (gyro-compass unit), but if one wants to control the ruddex-angle it is necessary to bend over the pelorus to read the rudder-indicator (hidden below to the fight). The helmsman and lee-helmsman are in a steering room below decks. Communication between the bridge and steering room is by the large voice pipe left of the pelorus. The chart table has a large fold-away, tent-like cover for use at night but the construction is such that even in daytime one can only work on one side of the table.
Fig 2 General view of the mock-up of the van Speyk-class bridge.
Applied Ergonomics
June 1971
67
A general view of the console in the mock-up is shown in Fig 4 (scale 1 : 1). The instruments which one needs to see when walking around the bridge are duplicated in larger size and mounted above the centre window. There are fresh water sprayers for the windows and vertical wipers run on a horizontal track.
I Fig 3
f
Ground-plan of the new bridge design.
windows is already very useful for the observation of the deck. For night viewing, however, sloping panes are a necessity as this prevents reflections of outside lights which can easily be mistaken for ships passing on the other side. The cover to shield the chart table from light is built in, so that it is possible to work on either side of the table. The chartlighting is built into the cover.
The improved bridge design In the new design we have tried to include all the advantages already discussed. The ground-plan of this new design is shown in Fig 3. Unfortunately 360 ° direct vision was impossible but we improved upon the problem with closed-circuit television. The conning console is located on the centre line in the front part of the bridge. All control equipment is integrated in the console. The helmsman, or if necessary the O.O.W., is positioned in the centre of the console and the commander is seated to the left of the helmsman. The commander's part of the console shows weapons and equipment status, and weapons assignment, and permits the commander to override decisions made elswhere. The microphone on the desk can be used for radio intercom' and there is a sound-power telephone which can be amplified and still be used as a sound-powered circuit when needed. The O.O.W. is seated to the right of the helmsman at his own part of the console.
Building a full-scale mock-up of a complete bridge is essential in order to handle the design as an integrated problem. Such a mock-up is extremely useful to simulate the whole working programme and discussions between the builders, users and advisers are much easier. The helmsman panel and one part of the O.O.W. panel are shown in Fig 5. The ship is equipped with two gas-turbines and the direct throttle control equipment is located in the centre of the console. The design of the handles is such that both are movable by one hand, but it is also easy to use two hands. If an equipment breakdown occurs, it is possible to use the handles as an engine-room telegraph. The direct throttle control is placed between the helmsman and the O.O.W. so that the O.O.W. can take over the control. On the left side of the helmsman is the automatic steering equipment. The advantage of such equipment is the ability to steer the ship on a more efficient path through open waters, which gives also a reduction in fuel consumption and ship wear. Another advantage is that the helmsman is free for other duties. On the right side on the O.O.W. panel, is the television monitor which shows the helicopter deck. This monitor can also be switched to survey other controls, ship status, weather reports etc. Further, by using a scanconverter in
The use of radar in day-time by means of a viewing hood is quite difficult. The radar repeater can be seen by one person at a time and then only correctly after the eyes have become adapted to darkness. Visual comparison between environment, map, and radar would be much easier without a hood. In this design the radar-sets are put in a separate cabin. This cabin has large window frames with movable filters. Depending on the brightness outside it is possible to use one or two filters or no f'dter. With this method it is possible to use the radar without a hood. The chart table is placed against the backwaU in this cabin and all the navigation equipment is placed above the table. There is one bearing repeater on the starboard side and one on portside. The repeaters are movable on a revolving arm to avoid blind parts of the window frame.
68
Applied Ergonomics June 1971
Fig 4 Survey of the control console (mock-up new design).
Fig 5
Helmsman panel and one part of the 0 0 W panel (mock-up new design).
combination with the radar set, it is possible to give a daylight TV-radarpicture on the monitor.
Future research It seems beyond dispute that automation and the full implementation of remote control will make great progress. Its development should be accompaniedby an extensive and objective ergonomic research programme. From an ergonomic point of view the real ship is the ideal equipment for experiments as the experimental situation is completely 'live'. But most of the time, it is impossible to put different technical systems aboard ship; and to carry out a research programme with different test subjects is also very difficult. Therefore, a useful method for research on human behaviour in ship handling is the simulation of navigation bridges with a computer and a visual display. The most important requirement for such a simulator is that the real situation is approximated as closely as possible.
In co-operation with the Institute TNO for Mechanical Constructions our institute has designed such a simulator (van den Brug and Wagenaar, 1968). This simulator is in use for determination of the human transfer function and for design studies of new systems. At the moment a series of experiments, executed with this experimental simulator, has provided some successful results. However, only extensive discussions about the possibilities with other scientists will result in an efficient use of all the facilities of this type of simulator.
References Brug, J. B. van den and Wagenaar, W. A. 1968 TNO-IWECO report no. 4587. An experimental simulator for the manoeuvring of surface ships. Lazet, A. 1968 Some application of closed-circuit television in ships. Defence Research Establishment, Toronto.
Applied Ergonomics June 1971
69
l-rgonomic aspects of automation in navigation bridges A. Lazet and P. L. Walraven Institute for Perception RVO-TNO, Soesterberg,The N~therlands
New ergonomic questions arise from the tendency towards increasing automation in maritime operations. Direct control of engines and rudder from the bridge promises improved ship control, provided that the operator can really exploit the technical improvements. To make such direct control most efficient, good ergonomic design is essential. A series of designs of navigation bridges is used to illustrate typical problems and situations. The building of full scale mock-ups of complete bridges is essential in order to handle the design as an integrated problem and to simulate the work situation. Such static mock-ups have been shown to be extremely useful in the discussion between builder, future user and adviser. An extension to dynamic simulation is necessary in order to study the actual work conditions in a new design.
With the growth of automation aboard ships, the task of the man is concentrated more and more upon the controlling functions. Consequently, a ship designer is increasingly confronted with design problems where the man-machine relationship involves the operator as controller. The desired increase of performance is achieved only if man's possibilities are put to their best use in this relationship. To obtain this, both man and the technical systems must be subjected to research. Knowledge must be gained about the ways in which they affect one another both in a favourable and in an unfavourable sense. In many cases a very advanced technical development does not live up to expectations because adaptation to human capabilities has been neglected. It is therefore important to consider the human perceptual and control capabilities when designing each particular system. The starting point for the research leading to a design is a proper statement of the requirements. Sometimes it occurs that there is a divergence of opinions among future users about what is actually needed to perform the task involved. If the requirements are not properly defined, the research has to start with defining them. The Institute for Perception has given the Royal Dutch Navy advice for different navigation bridges. The different designs of some of those bridges and the influence of automation will be discussed in this article.
66
AppliedErgonomics
June 1971
The bridge control of ships Ship handling without direct control of engines and rudder from the bridge has been practised for many years. It stems from the procedures used in sailing vessels. The most striking shortcoming in this control arrangement is the delay-factor and, more importantly, the possibility of error due to an inherently slow verbal system of passing and effecting orders. Up to now in most of the Royal Dutch Navy ships the helmsman is positioned in a closed wheelhouse 'below decks,' and the orders are passed from the bridge via microphone or voice pipe and by telegraph for engine orders. Each message must be repeated at least twice so that the information is doubly subject to error - once in transmitting, once in delivery. Between those orders, at the same time, three or four loud speakers are also blaring tactical instructions and signals. If the communication links can be reduced there clearly would be less delay and the risk of response error would be less. In the past little attention has been given to the arrangements of controls in relation to the user and most of the displays and controls are scattered about. The change to automation makes it more neccessary to centralise and integrate controls and displays in consoles. This brings these items to the user and practically eliminates the need for movement about the bridge. Normally it is expected that
bridge personnel stand while on bridge watch, but the use of integrated consoles will without a doubt place the bridge personnel firmly in seats. There is no specific ergonomic reason why personnel cannot be seated. The reason proposed against sitting down is that personnel would go to sleep. On the other hand, the seated operator tires less quickly. Furthermore, in rough weather it is easier to use controls in a sitting position than in a standing position. An investigation to determine the environmental factors affecting ship control showed that visibility must be given prime consideration. An ideal navigation bridge has 360 ° visibility, but most of the time the conventional design and placement of the bridge on many ships restricts visibility such that areas aft of the bridge are virtually blind. The use of closed-circuit television would improve visibility.
Fig 2 shows the mock-up of the van Speyk-class bridge. This is a redesign of the old bridge. The requirements are nearly the same as for the old bridge, but in this design we incorporate the ergonomic requirements. The central navigation position is also in the fore-front of the bridge behind the pelorus, but the instruments have been so arranged that all are at hand in the central position. The principal instruments have been mounted above the windows and are readable from each point of the bridge even from the wings. The large windows with panes sloping forward promote an excellent view. Inclination of panes of
In Canada one of the authors gained experience with the use of television (Lazet, 1968) to view the sections of the ship which have always been invisible from the bridge. It appeared that the co-operation of a helicopter and a submarine hunter becomes far more efficient if the ship commander can observe the touchdown and take-off of the helicopter by means of a monitor mounted on the bridge. The touchdown of a helicopter on a navigating ship requires quick and efficient teamwork with continuing course corrections. An interesting problem was whether the monitor should give the picture the commander would have seen if he could have looked straight backward or if he looked forward. In the latter case a considerable number of starboard/port errors might have occurred. Apparently the commander feels himself so much 'at his right place' on the bridge that his perception is not restricted to 'looking forward' only. Also, for general navigational purposes television offers many possibilities. The use of television-cameras high on the mast offers a far greater field of view than the bridge. Dead angles may be abolished by cameras mounted at high locations. In particular when manoeuvring in ports, mooring, bringing alongside etc an excellent view is necessary. It must be accepted that with future designs of navigation bridges the use of television must be taken into account from the beginning.
Fig 1
General view of the old destroyer bridge.
Development of bridge design In 1962 we started with the design of the navigation bridge of the van Speyk-class frigate. In order to gain some experience regarding the manipulations, the communication, and the time these actions consume on the bridge, some visits were made aboard destroyers which were built in 1954. Fig 1 depicts the old bridge. The whole design is overloaded with ergonomic mistakes. Visibility, the most important factor for navigating, is very poor, and the instruments are scattered around. The central navigating position is facing the pelorus (gyro-compass unit), but if one wants to control the ruddex-angle it is necessary to bend over the pelorus to read the rudder-indicator (hidden below to the fight). The helmsman and lee-helmsman are in a steering room below decks. Communication between the bridge and steering room is by the large voice pipe left of the pelorus. The chart table has a large fold-away, tent-like cover for use at night but the construction is such that even in daytime one can only work on one side of the table.
Fig 2 General view of the mock-up of the van Speyk-class bridge.
Applied Ergonomics
June 1971
67
A general view of the console in the mock-up is shown in Fig 4 (scale 1 : 1). The instruments which one needs to see when walking around the bridge are duplicated in larger size and mounted above the centre window. There are fresh water sprayers for the windows and vertical wipers run on a horizontal track.
I Fig 3
f
Ground-plan of the new bridge design.
windows is already very useful for the observation of the deck. For night viewing, however, sloping panes are a necessity as this prevents reflections of outside lights which can easily be mistaken for ships passing on the other side. The cover to shield the chart table from light is built in, so that it is possible to work on either side of the table. The chartlighting is built into the cover.
The improved bridge design In the new design we have tried to include all the advantages already discussed. The ground-plan of this new design is shown in Fig 3. Unfortunately 360 ° direct vision was impossible but we improved upon the problem with closed-circuit television. The conning console is located on the centre line in the front part of the bridge. All control equipment is integrated in the console. The helmsman, or if necessary the O.O.W., is positioned in the centre of the console and the commander is seated to the left of the helmsman. The commander's part of the console shows weapons and equipment status, and weapons assignment, and permits the commander to override decisions made elswhere. The microphone on the desk can be used for radio intercom' and there is a sound-power telephone which can be amplified and still be used as a sound-powered circuit when needed. The O.O.W. is seated to the right of the helmsman at his own part of the console.
Building a full-scale mock-up of a complete bridge is essential in order to handle the design as an integrated problem. Such a mock-up is extremely useful to simulate the whole working programme and discussions between the builders, users and advisers are much easier. The helmsman panel and one part of the O.O.W. panel are shown in Fig 5. The ship is equipped with two gas-turbines and the direct throttle control equipment is located in the centre of the console. The design of the handles is such that both are movable by one hand, but it is also easy to use two hands. If an equipment breakdown occurs, it is possible to use the handles as an engine-room telegraph. The direct throttle control is placed between the helmsman and the O.O.W. so that the O.O.W. can take over the control. On the left side of the helmsman is the automatic steering equipment. The advantage of such equipment is the ability to steer the ship on a more efficient path through open waters, which gives also a reduction in fuel consumption and ship wear. Another advantage is that the helmsman is free for other duties. On the right side on the O.O.W. panel, is the television monitor which shows the helicopter deck. This monitor can also be switched to survey other controls, ship status, weather reports etc. Further, by using a scanconverter in
The use of radar in day-time by means of a viewing hood is quite difficult. The radar repeater can be seen by one person at a time and then only correctly after the eyes have become adapted to darkness. Visual comparison between environment, map, and radar would be much easier without a hood. In this design the radar-sets are put in a separate cabin. This cabin has large window frames with movable filters. Depending on the brightness outside it is possible to use one or two filters or no f'dter. With this method it is possible to use the radar without a hood. The chart table is placed against the backwaU in this cabin and all the navigation equipment is placed above the table. There is one bearing repeater on the starboard side and one on portside. The repeaters are movable on a revolving arm to avoid blind parts of the window frame.
68
Applied Ergonomics June 1971
Fig 4 Survey of the control console (mock-up new design).
Fig 5
Helmsman panel and one part of the 0 0 W panel (mock-up new design).
combination with the radar set, it is possible to give a daylight TV-radarpicture on the monitor.
Future research It seems beyond dispute that automation and the full implementation of remote control will make great progress. Its development should be accompaniedby an extensive and objective ergonomic research programme. From an ergonomic point of view the real ship is the ideal equipment for experiments as the experimental situation is completely 'live'. But most of the time, it is impossible to put different technical systems aboard ship; and to carry out a research programme with different test subjects is also very difficult. Therefore, a useful method for research on human behaviour in ship handling is the simulation of navigation bridges with a computer and a visual display. The most important requirement for such a simulator is that the real situation is approximated as closely as possible.
In co-operation with the Institute TNO for Mechanical Constructions our institute has designed such a simulator (van den Brug and Wagenaar, 1968). This simulator is in use for determination of the human transfer function and for design studies of new systems. At the moment a series of experiments, executed with this experimental simulator, has provided some successful results. However, only extensive discussions about the possibilities with other scientists will result in an efficient use of all the facilities of this type of simulator.
References Brug, J. B. van den and Wagenaar, W. A. 1968 TNO-IWECO report no. 4587. An experimental simulator for the manoeuvring of surface ships. Lazet, A. 1968 Some application of closed-circuit television in ships. Defence Research Establishment, Toronto.
Applied Ergonomics June 1971
69