Animatronics - A SEMINAR


1. Introduction.

 

            Animatronics is “the technology employing electronics to animate motorized puppets”. The animatronics system is based on the “system reality”. The animatronics figures are mainly created for entertainment. At the heart of any animatronics figure we will find the power system. Simply put, the power system, this is responsible for making figure to move. The movement can be done by various types of motors and actuators. The movements of various parts in animatronics figure is controlled by electronic control system. This electronic control system is treated as brain to control the movements of animatronics figures. The commonly used methods are Hydraulic systems and Pneumatic systems. These methods are used separately or in combination along with other technologies to create animatronics figures. Hydraulic systems gives higher accuracy, while Pneumatic systems are easier to design and operate. Hydraulic systems have number of advantages over Pneumatic systems and are generally superior in reproducing exact movements.

 

2. What is animatronics? What are they used for?

 

             Animatronics is “the technology employing electronics to animate motorized puppets” (The American Heritage Dictionary). An animatronics figure is often used in movies to create grand special effects. Examples of these figures include the giant dinosaurs of Jurassic Park, the title character from ET, and the personable robots from Star Wars. The advantage animatronics has over digital effects in some movies is more realistic close-up shots. Another use of animatronics in the entertainment industry is in theme parks. Rides such as “It’s a Small World”, “Pirates of the Caribbean”, and “Country Bear Jamboree” at Disneyland all include animatronics to transport the visitor into a new, lifelike, fantasy world. Animatronics are a specific type of robot. They defer from common robots such as robots used in search and rescue operations, in space, and in deep water because animatronics figures are not designed to be intelligent. Instead, they have been created mainly to entertain. Unlike many modern robots who respond to external stimuli, animatronics imitate the movements of intelligent characters with pre-programmed motions, words, and songs.


3. How are Animatronics created?

 

The animatronics figure can be created by following methods,

  1. Creating paper designs:

            The first step to creating Animatronics is to sketch the initial idea and create a paper design. Depending on the specifics of the project, different experts are brought in. During the creation of Jurassic Park’s Spinosaurus, paleontologists advised on the accuracy of the initial design. In the creation of “It’s a Small World”, color stylist and designer Mary Blair was assigned the job of drawing the children. These paper representations of the final animatronics figure tell engineers and artists in each following step what the goal is for the end creation.

 

 

Fig. An artist sketches the  Spinosaurus.

 


  1. Preparing Maquette:

            After the paper design has been finalized, the next step is to create a maquette, or miniature model of the final design. This model is often made out of clay. It is especially important to create a maquette when building very big animatronics because it tests the feasibility of the paper design without wasting the time and resources that would be needed to build a full-scale model. The maquette also allows designers to add the 3-dimensional, surface detail that is difficult to depict in sketches.

 

Fig: Maquette of the Spinosaurus

 

3. Build a Full-size Sculpture:

            The completed maquette is used to build a full-sized sculpture of the final creature. While this used to be done by hand, computer-aided manufacturing has automated the process. The maquette is scanned with a series of very precise lasers and then the final sculpture is milled out of foam. If the animatronics figure is very large, the final sculpture is milled in pieces and then secured together with special glue.

 

Fig. Full-size sculpture.

4. Molding and Casting:

            Next, the full-sized sculpture is used to create a mold so that the body can be cast out of foam rubber to create the skin. The skin is very important to the animatronics character’s ability to function because the character must usually look natural. Skin that is too thick and difficult to move would cause clumsy movements.

 

Fig. Creating the mold.

 

5. Creature Creation:

            The next step in creating an animatronics figure involves the largest number of engineers. It is building the various animatronics components which allow the animatronics figure to evolve from “puppet” or “sculpture” to “animatronics”.

 

Fig. Creating head of T-Rex.

 

            The “skeleton” of an animatronics figure often resembles the skeletons of animals in the real world. It gives the figure structure and holds the pieces together. An alternative to the traditional inner skeleton is an outer-skeleton, like the exoskeleton of an insect. The advantage to this model is more room inside the figure for other parts.

 

            The mechanical parts of the animatronics figure create the “muscles” that create movement of the skeleton. Some animatronics (such as the characters of “It’s a Small World”) have few moving parts, and therefore require fewer “muscles” which can be made with basic mechanisms. Newer, more modern, animatronics figures, however, involve complex systems of hydraulics or pneumatics. Hydraulics offer higher accuracy, while pneumatics are easier to design and operate. Despite this complexity, most of the mechanical parts in animatronics figures come from the basic wedge, screw, lever, pulley, wheels, and gears, just like the early automata. What has grown more sophisticated is how these mechanisms are powered.

 

Fig. All hydraulic systems are installed and checked.

 

            A “brain” is needed to control the “muscles”, and so electronic control systems are created to operate the animatronics figure. These systems are created by electrical engineers with custom circuit boards. Some animatronics are manipulated through telemetry. This allows a puppeteer to control the movement off-screen. For figures made to repeat their movements many times at a theme park, their movements may be programmed into the figure, so that the figure may operate on stage without constant attention.

 


6. Putting it together:

 

Fig. The "skeleton" of the Spinosaurus.

            Finally, the skeleton, the mechanics, and the electronics are fitted together with the skin to complete the animatronics figure. It is very important at this stage in the design process to ensure there has been clear communication between the groups responsible for different parts of the design process. The final finishing touches, such as sculptural details are then added and the figure is put through a series of final tests to ensure its dependability.

 

Fig. Painting the skin.

 

4. An Animatronic System Including Lifelike Robotic Fish

 

            It is well known that marine creatures, such as fish, that swim using small power as well as at high speeds (dolphin: 60 km/h, swordfish: 80 km/h) are superior in their position-keeping characteristics. These characteristics as creatures have been of interest to science for a long time, and much research has been conducted however, it is rare to study these characteristics from the viewpoint of engineering. The purpose of this research is a flexible oscillating fin control system which could be used for the propulsion of marine vehicles by positively making most of the characteristics of the flexible part. This method obtains a propulsion force by oscillating fins equipped to vehicles on the analogy of the motion of marine creatures. After the control system for a flexible oscillating fin propulsion device and the oscillating fin driving device were designed and manufactured, a cruising test was performed, first by a numerical simulation and then with a model ship, and the fundamental performance has been grasped and prospects of putting the devices to practical use have been obtained. Robotic fish for amusement in aquariums, etc., have been developed as an applied product.

            Advantages of the oscillating fin propulsion system have been found and products of application have been created by the research.

4.1 BASIC OSCILLATING FIN PROPULSION SYSTEM

            In many cases, the kinetic parameters of the oscillating fin cannot be directly detected in control of an oscillating fin, and there are problems choosing and identifying parameters to be used for control; a control system able to cope with such problems should be architected.

            In the research, to cope with the above problems, a study on the application of neural network learning control has been made using a model ship. The control algorithm is architected and the control computer software has been mounted; the cruising test was then conducted in a tank.

            Fig. 1 shows the outline of the test device for the oscillating fin propulsion system which has been developed for the basic tank test. The neural network learning algorithm has been created in the control device. It consists of a hierarchy network of three layers, which are input, middle, and output layers. The Hess and Smith method has been expanded to a non-stationary problem; furthermore, a model applying the method of solving deformation of the wake vortex using the discrete vortex method has been used, and the I/O variables and node numbers of the middle layer have been determined by simulation.

            From Fig. 1, the input signals are formed to give the ship speed, the propulsion thrust, the learning signal, and the output signal to give the vibrating frequency, phase angle, sway angle, and yaw angle amplitudes. The node number of the middle layer was determined to be four from the viewpoint of error energy function and simplification of the system.

    

Fig. 1. Test device.

            The two-phase control oscillator, ac servo control amplifier, oscillating fin driving device, and small-sized three-component force block gauge for fluid measurement were designed and manufactured for this test. The oscillating fin driving device was designed to be actuated linking sway direction motion with yaw direction motion by mounting the yaw direction driving device on the sway direction driving device.

 

            The oscillating fin is actuated by varying the amplitude, phase difference, and oscillating frequency of sway and yaw motion. The oscillating fin consists of rigid and flexible parts and the propulsion efficiency is improved by the flexibility of the flexible part. The control computer consists of the neural network software and the command generator. The command generator gives the command values of the sway and yaw motion parameters of the oscillating fin. During the optimal adjustment of motion parameters of the oscillating fin in the cruising test, the neural network gets the learning data for back propagation. After the network was constructed by back propagation, the oscillating fin is actuated only by the neural network control and can self-cruise the vehicle.

 

4.2 EXPERIMENTAL TEST OF OSCILLATING FIN

            The flexible oscillating fin propulsion device was produced experimentally, and only the flexible oscillating fin propulsion device was independently tested before loading it onto a model ship to examine the influence of the oscillating fin shape and the flexible part on propulsion. The oscillating fin propulsion device was loaded onto a model ship and the tank cruising tests were carried out. The purpose of the tank tests was to grasp the propulsion characteristics as a ship's actuator and self-cruising capability using only the neural network.

 

            Fig. 2 shows the model ship with the oscillating fin propulsion device. During the cruising test and by using the command generator, the cruising test learning data for the neural network control is accumulated and the weights in the neural network are determined by back propagation. The oscillating fin driving command signal is given by the forward operation in the neural network, based on the target value command, and then the model ship cruises. Also, transition of the thrust force from a positive to a negative direction can be conducted smoothly only by changing the phase angle of the sway and yaw motion. Therefore, it was found that the transition of the thrust force from progress to reverse of the vehicle can be conducted smoothly.

 

            Moreover, propulsive thrust and efficiency can be improved by using a flexible part of the oscillating fin. The characteristics can be further improved by improving the fin shape. The fish-tail-type fin is found to produce higher power compared with the same area of a rectangular fin.

 

Fig. 2. Ship model with the oscillating fin propulsion device.

 

 4.3 LIFELIKE ROBOTIC FISH DEVELOPMENT

            Fig. 3 shows the principle of the control system based on the technical research of the flexible oscillating fin propulsion system. We can control the fish by regulating the amplitude, frequency, and phase of the joints of the fin. Here, sway direction motion of the oscillating fin can be achieved from the front joint angle of the fish and yaw direction motion from the rear joint angle, respectively. Robotic fish have been developed as an applied product of this system.

 

Fig. 3. Principle of control of robotic fish.

 

            Batteries and a buoyancy control device are built into the robotic fish, and three-dimensional movement of the robotic fish is possible by remote control, using underwater wireless information communication. It is generally thought that it is difficult to transmit a signal underwater using the radio wave because the attenuation of the radio wave underwater is large. However, it is actually possible to transmit a signal underwater by using appropriate frequency and modification. The computer wireless maneuvering control device and noncontact submerged charging equipment as peripheral equipment have been developed and continuous swimming can be conducted for hours. The controller was designed and checked based on such hydrodynamic tests. Advanced control algorithms were also applied to the robotic fish. Optimization of the fin shape was conducted by nonlinear programming and genetic algorithm. Artificial intelligence (AI) and chaos control were tried to simulate the real fish maneuvering. An example is shown in Fig. 3.1. A very realistic and lifelike swimming method can be realized by the flexible oscillating fin propulsion.

 


Fig. 3.1. Hydrodynamic tests of robotic fish.

  

4.4 ANIMATRONIC SYSTEM

            This research is extremely important in technology for the new field of animatronics a computer-controlled biomechanically engineered model, in this case, aquatic creatures.


            Animatronics technology is rapidly gaining popularity throughout the world. It can be applied to create a virtual aquarium not possible with computer graphics technology alone. We have developed a method of enhancing event spaces that included animatronics for modern-day fish, coelacanths, and Cambrian-world creatures able to swim under their own electrical power. The concept of the system is shown in Fig. 4. Spectators will be able to see the various lifelike fish robots swimming in the tank. By using voice treatment technology and image recognition technology, they will use variety variation functions where the fish answers to a voice or the fish reads a number card.

 

Fig. 4. Concept of the animatronics system.

 

 

Fig.5. Block diagram of the control system.


            It is very difficult to detect the motion of a controlled oscillating fin directly; therefore, a control system needs to be constructed so as to solve the problem of choosing and identifying the control parameters. Furthermore, unless a mathematical model for the oscillating fin is created, designing a model based on the control system becomes too difficult.

 

            Various systems were tried; ultimately, a combination of neural network, chaos, and other systems has been applied to reproduce the motion of the fish naturally and realistically with the robots. As for the control algorithm, software was made and added to the control computer device; then a tank cruising test using software was performed.
The block diagram of the control system is shown in Fig. 5. Via a computer, supersonic sensors, controllers, and the oscillating fin generate, adjust, and control the motion of the robotic fish. The control computer consists of the control software and a command generator, which produces sway and yaw motion parameters for the oscillating fin.

 

4.5 EVALUATING REALISM:

            This animatronics system is based on the “system reality” model whereby spectators take pleasure in watching the robotic fish swimming in the tank. The premise is that reality appeals to human sensitivity. The spectators compare the known image in their brain with the robotic image before them and determine the level of realism (and by extension the level of pleasure). However, if spectators have not seen real fish swimming, they cannot evaluate the realism of the robotic fish because they have no strong impression from which to draw comparisons. On the other hand, if the spectator has at some point in the past seen the real fish in action, then their excitement at the sight of the robotic model will be greater. For this reason, we have chosen to have the spectators evaluate the realism of an animatronics sea bream, a species of fish well known to Japanese spectators.

 

5. What is the future for animatronics?

           

            It can be speculated that animatronics will not be a large player in the future of cinematic special effects and theme parks. Because of the growing ease and versatility of computer graphics, animatronics are being used less and less to render life-like fantasy creatures in movies. It is much less expensive to create a digital version of imaginary monsters, then to build them in a life-like size. The other main use for animatronics, theme parks, has also seen a decline in the need for mechanized puppets. Newer theme parks are built around attractions such as roller-coasters and the importance of visual stimulation such as animatronics figures has been downplayed in favor of the thrill of an adrenaline rush. Furthermore, the initial wow-factor which applied to animatronics when the Enchanted Tiki Room has worn off because of an audience used to seeing many the technological marvels on television and through the Internet. Nevertheless, animatronics (and their father, the puppet) have played a large role in the theatre for a long time and that is unlikely to change unless theatre as a whole becomes less important with the easy accessibility of movies and television.

 

6. Conclusion

 

 

            From the study of animatronics we can say that animatronics figures are often used in movies to create grand special effects. Animatronics has over digital effects in some movies is more realistic close-up shot. Animatronics figures are not designed to be intelligent; instead they have been created mainly to entertain. Animatronics imitates the movements of intelligent characters with pre programmed motions, words and songs. Animatronics figures move by various types of motors and actuators. It can be speculated that animatronics will not be a large player in future of cinematic and fantasy world.

 

            The main use for animatronics has decline in the need for mechanized puppets. Nevertheless, animatronics have played a large role in the theater for long time.  In case of robotic fish one fin can control both the thrust force and its direction simultaneously. Then a compact actuator can be constructed. For robotic fish, the fins flexibility can be utilized actively. It is therefore possible to improve the propulsion performance. For robotic fish realistic movement becomes possible by making the oscillating fin propulsion control system and buoyancy control system. Transmission of radio signals under water is possible for robotic fish control.

 

REFERENCES

1.      Yoshida, Fune no Kagaku (Science of Ships) Tokyo, Japan: Kodansha, 1976.

2.      H. Hertel, Biology and Technology New York: Reinbold, 1966, pp. 110-190.

3.      Isiki, et al., “Research on oscillating fin propulsion,” J. Naval Architects Jpn., vol. 642, 1983.

4.      I. Yamamoto and Y. Terada, “Research on an oscillating fin propulsion control system,” in Proc. IEEE OCEANS 1993, vol. 3, pp. III/259-III/263.
[Abstract]  [PDF Full-Text (268KB)]

5.      J. Hess, et al., “Calculation of potential flow about arbitrary bodies,” Prog. Aeronaut. Sci., vol. 8, pp. 1-138, 1996. [CrossRef] 

6.      A. Kubota, et al., “Study on propulsion by partially elastic oscillating foil,” J. Naval Architects Jpn., no. 156, pp. 95-105, 1985.[7] I. Yamamoto and Y. Terada,

7.      “Development research of oscillating fin propulsion system,” in Proc. Annul. Conf. Soc. Instrument and Control Engineers, 1994, pp. 37-38.

8.      I. Yamamoto and Y. Terada, “Design of a maneuvering control system for a ship,” Trans. West-Jpn. Soc. Naval Architects, no. 83, pp. 96-100, 1994.

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