Milestone-Proposal:Computer-controlled aerial ladder systems
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To the proposer’s knowledge, is this achievement subject to litigation? No
Is the achievement you are proposing more than 25 years old? Yes
Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes
Did the achievement provide a meaningful benefit for humanity? Yes
Was it of at least regional importance? Yes
Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes
Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes
Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes
Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes
Year or range of years in which the achievement occurred:
Title of the proposed milestone:
Computer-controlled aerial ladder systems, 1985.
Plaque citation summarizing the achievement and its significance:
Morita Corporation released world’s first computer-controlled aerial ladder systems in 1985. Specifically, the horizontally leveling system was run for making the vehicle horizontal, and the ladder driving system was for achieving elevation/depression, extension/retraction, rotation, and lifter by controlling the oil flow at paired derricking cylinders, paired telescopic cylinders, rotation motor, and lifter motor, respectively, with each system employing a Zilog Z80.
In what IEEE section(s) does it reside?
IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:
IEEE Organizational Unit(s) paying for milestone plaque(s):
Unit: Kansai Section
Senior Officer Name: Toshiharu Sugie
IEEE Organizational Unit(s) arranging the dedication ceremony:
Unit: Kansai Section
Senior Officer Name: Toshiharu Sugie
IEEE section(s) monitoring the plaque(s):
IEEE Section: Kansai Section
IEEE Section Chair name: Toshiharu Sugie
Proposer name: Isao Shirakawa
Proposer email: Proposer's email masked to public
Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.
Street address(es) and GPS coordinates of the intended milestone plaque site(s):
1-5 Techno Park, Sanda-shi, Hyogo, 669-1339 Japan; N 34.934300, E 135.174900
Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.
Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. corporate building
Are the original buildings extant?
Details of the plaque mounting:
The plaque will be displayed within a glass case in the main building of Sanda Factory, Morita Corporation.
How is the site protected/secured, and in what ways is it accessible to the public?
The main building of Sanda Factory can be accessible to the public with permissin to enter.
Who is the present owner of the site(s)?
What is the historical significance of the work (its technological, scientific, or social importance)?
The major historical significance concerning world’s first computer-controlled aerial ladder systems is described in what follows.
1. Historical background: Morita Corporation released Japan’s first aerial ladder truck with a 18m-length wooden ladder in 1933 and world’s first computer-controlled ‘Super Gyro Ladder Series ’ ladder systems of Fig. 1 in 1985. Unlike the conventional ladder trucks, each of the new series aerial ladder systems was equipped with those distinctive facilities of Gyro Controller, Main Control Station, Basket, Ladder Controller, and Security Devices, which were intended for driving securely ladder actions by means of newly introduced two 8-bit microcomputers and several connected sensors . In what follows this proposal will brief computer control schemes developed dedicatedly for these facilities.
2. Computer implementation of the horizontally leveling system: The turntable located at the rear of the vehicle consisted of four rings (two tilt rings, a lower ring, and an upper ring). A computer system, Gyro Controller, was installed to rotate the two tilt rings to bring the ladder base to the required horizontal level as illustrated in Fig. 2 , using a Zilog 8-bit microcomputer Z80 . Specifically, the information of how much to rotate clockwise or anti-clockwise each of the upper and lower tilt rings was sought in the form of a numeration table by reference to the inclenation sensor [5,6]. Subsequently, with the use of a Zilog Z80 the Gyro Controller rotated first the lower tilt ring and then the upper tilt ring, in such a way that the rotation of each tilt ring was stopped by inserting the lock-cylinder shown in Fig. 3 into that one of the holes bored at the regular intervals in the ring, whose location was specified by the numeration table .
3. Computer implementation of the ladder driving system: All ladder actions were activated by operating two joysticks provided both in the Main Control Station and in the Basket, one for elevation/depression/rotation, and the other for extension/retraction/lifter. These ladder actions were achieved by controlling the oil flow at each of their dedicated hydraulic cylinders with the use of a Zilog Z80, as follows .
1) Elevation/Depression: The ladder actions of elevation/depression were activated by operating the joystick either in the Main Control Station or in the Basket, and driven by the paired derricking cylinders shown in Fig. 4. Given a ladder length, to raise/depress the basket at a certain speed, the oil flow at the derricking cylinders could be controlled empirically by operating the joystick at each elevation angle, Thus, an optimal oil flow control mechanism was devised for the derricking cylinders, using a Zilog Z80 installed in the Main Control Station.
2) Extension/Retraction: The ladder actions of extension/retraction were driven by the paired telescopic cylinders. Given either an elevation angle or a depression angle, the basket extending/retracting speed, therefore the oil flow at the paired telescopic cylinders, could be controlled empirically by operating the joystick. Thus, an optimal oil flow control mechanism was devised for the telescopic cylinders, using a Zilog Z80 in the Main Control Station.
3) Rotation: The ladder actions of rotation were driven by the rotation motor cylinder. Given a ladder length and either an elevation angle or a depression angle, to rotate the basket at a certain speed, the oil flow at the rotation motor cylinder could be controlled empirically by operating the joystick. Thus, an optimal oil flow control mechanism was devised for the rotation motor cylinder, using a Zilog Z80 in the Main Control Station.
4) Lifter: The up and down actions of lifter were driven by the lifter motor cylinder. Given either an elevation angle or a depression angle, the up/down speed of the lifter could be controlled empirically by operating the joystick. Thus, an optimal oil flow control mechanism was devised for the lifter motor cylinder, using a Zilog Z80 in the Main Control Station.
Therefore, all ladder actions were driven securely with the use of a Zilog Z80 and several sensors, such as ladder length potentiometer, elevation angle potentiometer, depression angle potentiometer, ladder rotational direction and position detection sensor, etc.
What obstacles (technical, political, geographic) needed to be overcome?
1. Obstacles to the alternative choice between Zilog Z80 or Intel 8080: On the occasion of developing world’s first computer-controlled ladder systems, there was the alternative choice of which 8-bit microcomputer of Intel 8080  or Zilog Z80 had to be adopted. The main reason why Morita Corporation managed to select Zilog Z80 against Intel 8080 is briefed as follows: Since Sharp Corporation (Osaka, Japan) decided to be a second source of Zilog Z80 in 1976, the design environments of 8-bit microcomputers in Japan became drastically progressed in the early 1980s with a central focus not only on the bestselling Intel 8080 but also on its upward compatible Zilog Z80. Seeing that in case Intel 8080 was used for system design, triple-source circuits had to be constructed for 5V, 12V, and -5V, whereas in case Zilog Z80 was used, only single-source circuits were necessary for 5V, Morita Corporation made the final decision to select Zilog Z80 against Intel 8080 because of easier design labor.
2. Obstacles to providing facilities to drive securely ladder actions: In order to drive securely ladder actions using newly introduced microcomputers and sensors, each ladder truck was equipped with those essential facilities; the Gyro Controller for making the ladder base strictly horizontal, the Main Control Station for controlling precisely the ladder driving, the Basket for achieving each ladder action, the Ladder Controller for controlling securely ladder actions, and the Safety Device for avoiding malfunction; for each of which an elaborate set of computer procedures had to be devised.
3. Obstacles to the visualization of physical data of ladder systems: With the aim of achieving ladder actions intended not only for firefighting but also for rescue activities, distinct physical data of ladder systems; such as ladder length, elevation angle, height of ladder-top, location of ladder-top relative to that of turntable, current working radius, ladder-top operational limit baseline, etc.; had to be visualized so that the operator could achieve securely each ladder action. Hence, a mechanical display panel as shown in Fig. 5 managed to be constructed by patching a number of printed acrylic plate pieces to depict their real time figures using a Zilog Z80, which enabled the operator to perform precisely each ladder action.
What features set this work apart from similar achievements?
There are a number of distinctive features of world’s first computer-controlled ladder systems released in 1985, as summarized below.
1. The first adoption of microcomputers for implementing aerial ladder systems: Unlike the conventional ladder trucks, each of the new series aerial ladder systems released in 1985 was equipped with newly introduced two Zilog Z80’s. Specifically, one of the two Z80’s was employed for the horizontally leveling system to compensate the vehicle inclination and to maintain the ladder base horizontally in all directions, and the other was for the driving system to achieve each distinct ladder action of elevation/depression, extension/ retraction, rotation, and lifer. Here, it should be noticed that according to , Magirus GmbH (Ulm, Germany), which was the inventor as well as world’s leading manufacturer of aerial ladder trucks, reveals that it released the computer-controlled aerial ladder systems for the first time in 1986, one year later than Morita Corporation.
2. The introduction of security devices for operating ladder systems: In addition to the mechanical security devices; such as the outrigger/jack interlock device, the breaking device for the rotation motor, the security-locking device for lifter motor, the pilot check valves installed in the paired derricking cylinders and paired telescopic cylinders, etc.; the computational security devices for slow starting/stopping of ladder actions were also newly introduced with the use of a Zilog Z80 to avoid any abrupt ladder action due to the sudden operation by an operator, where the slow starting/stopping of any ladder action was achieved by slowing down the oil flow initiation/termination at its dedicated cylinder .
3. The visualization of physical data necessary for achieving ladder actions: As already stated, different physical data indispensable to driving securely all ladder actions were visualized on a mechanical display panel, in other words, the display panel shown in Fig. 5 was constructed by patching a numer of printed acrylic plate pieces with the use of a Zilog Z80. The visualized information on this display panel enabled the operator not only to monitor the whole ladder system but also to drive precisely each ladder action. Thus, this visualization greatly contributed to the secure ladder driving.
Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.
 https://www.morita119.jp/fire_engine/ladder/003.html (in Japanese).
 S. Seki, N. Sakamoto, A. Yamada, and I. Shirakawa, “History of Morita’s development of computer control mechanisms for fire ladder trucks”, IEEE HISTELCON 2019, Glasgow, UK, September 18-19, 2019.
 Tokyo Fire Department (ed.), “Technologies for Operating Ladder Trucks”, 4th ed., Public Service Foundation Tokyo Consolidated Fire Association, Chiyota-ku, Tokyo, 1983 (in Japanese).
 Japanese Patent No. JP.H0141598.B2, “Method of inclination compensation of the vehicle by means of the outriggers and tilt rings”, March 19, 1986 (in Japanese).
 Japanese Patent No. JP.H0141599.B2, “Method of automatic inclination compen-sation of the ladder base”, March 19, 1986 (in Japanese).
 Japanese Patent No. JP.H0647439.B2, “Method of inserting the lock-cylinder into the till ring”, November 16, 1989 (in Japanese).
 Japanese Patent No. JP.S582920.B2, “Method of slow starting/stopping of ladder actions”, February 23, 1979 (in Japanese).
Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to firstname.lastname@example.org. Please see the Milestone Program Guidelines for more information.
Attachment 1：Reference  is an IEEE Conference paper presented at HISTELCON 2019, held in Glasgow, UK, on Sept. 19, 2019, which describes the history of Morita Corporation’s development of computer-controlled ‘Super Gyro Ladder Series’ aerial ladder systems released in 1985.
Attachment 2：Reference  was written in Japanese, for which English summaries are briefed as follows: This book consists of 12 chapters, each of which describes the details of practical technologies for designing, assembling, and operating aerial ladder parts/systems.
Attachment 3: Reference  was written in Japanese, for which English summaries are briefed as follows: This patent describes a method of designing an inclination compensation mechanism of the aerial ladder vehicle by means of four outriggers and two tilt rings.
Attachment 4: Reference  was written in Japanese, for which English summaries are briefed as follows: This patent describes a method of operating an automatic inclination compensation mechanism of the aerial ladder base by rotating two tilt rings.
Attachment 5: Reference  was written in Japanese, for which English summaries are briefed as follows: This patent describes a method of inserting the lock-cylinder into the lower/upper till ring, intended for automatic inclination compensation of the aerial ladder base.
Attachment 6: Reference  was written in Japanese, for which English summaries are briefed as follows: This patent describes a method of devising computer procedures of slow starting/stopping of each aerial ladder action.
As for figures, see the pdf version of 'Milstone Figures'.
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