|Background - Computerized training simulators have existed for many years and are widely used in many industries. For example, commercial airline pilots are required to spend a certain number of hours in a simulator before flying the real plane. The same training benefit can be seen with operators of large cranes. Technical advances over the years have reduced costs and increased functionality.
Simulator Training provides the greatest benefit
|Using crane simulators can significantly reduce accidents, reduce the training time in real equipment and reduce the total training time. Considering only the cost of operating real equipment and instructor time, crane simulation can reduce annual training costs by more than 50%. There is no danger to equipment or people with “accidents” in the simulator. Can one assign a monetary value to that? Today, crane simulation is used for training in schools and ports around the world. Professional crane simulators range in cost from US$50,000 to over US$1,000,000 depending on functionality and the level of realism.|
|For simulators, the level of reality equals the level of training benefit. This paper will discuss the aspects of good simulation such as: the visual model & displays, physics, controls, motion system and the instructor station.|
|Visuals - The visual model includes the 3D image of the area for the crane simulation. It may be a port with ships and containers or a construction site with partial buildings and vehicles. Visual models of objects should be accurate and should create life-like effects. For example, the loads should cast shadows to aid in realism and depth perception. On the other hand, there should be enough detail to provide realistic images without slowing down the real time computations. The visual refresh rate should be at least 60 times per second. Any slower and the image will be jerky. This would be hard on the operator’s eyes and unrealistic.
Each visual channel may be either an LCD display or a projector & screen. Also, each visual channel requires a computer to calculate the images displayed on that channel. The number of visual channels can range from one to over 10.
|Software Physics – Simulators must behave in the same way as in real life. Loads must stop or bounce when colliding with other objects. Movement of ships in the water must be natural. Video games with explosions, etc. are for entertainment. Because crane simulators are for training, they might not be as exciting.|
|Controls - Low-level simulators have no motion system and the controls are simple and generic. High-level simulators have controls that look and behave like real crane controls. The picture below shows controls for different types of cranes that can be used on one simulator from GlobalSim. This allows the user to begin with a simulator for STS crane training. But, it takes only a few minutes to exchange the controls for an RTG crane.|
|Motion Systems - One of the factors that most contribute to the feeling of realism is a motion system. Motion can occur in a number of axes. Flight simulators need to have six degrees of freedom (6 DOF) – roll, pitch, yaw, surge, sway, and heave. But it is important to understand that not all crane simulators need this kind of movement. For example if a STS Quay crane is rotating, then the crane is broken. As shown in the chart below, most cranes only need 3 DOF. It makes no sense to pay for 6 DOF if you don’t need it.|
|Motion Cues||Container Gantry / RTG / RMG Cranes||Construction Crane||Pedestal or Jib Cranes||Straddle Carrier|
|Surge (Front to Back)||X||X|
|Sway (Side to Side)||X||X|
|Pitch (Forward Tilt)||X||X||X||X|
|Roll (Sideways Tilt)||X||X||X|
|Heave (Up and Down)||X|
|Instructor Station - Professional crane simulators include an instructor station. The instructor can create different training scenarios. Different weather conditions are available such as rain or snow. Students can practice in a day or night time environment. The instructor can establish wind speed and direction. The instructor can also induce failures such as having a spreader get stuck in the cargo hold. Of course, the instructor software keeps an extensive database of individual students’ performance. The database records contain number of moves per hour, number of collisions, etc.|
Virtual Reality – What about a VR Crane Simulator?
| One of the exiting developments in crane training simulation is the advancement in Virtual Reality (VR) or Augmented Reality (AR) technology.
VR crane simulation has both advantages and disadvantages. The primary advantage of VR crane simulators with a head set is the unlimited field of view (FOV). With traditional crane simulators, if the operator needs to see something to the right or left side, additional displays need to be added to the right and left side. In other words, to increase the operators field of view, the simulator needs more visual channels. This increases the cost and size of the simulator.
|One key issue in crane training is the operators need to see their hands on the controls. Many VR systems used for entertainment only allow the user to see interesting scenes. They can’t see their hands interacting with physical objects. For a VR crane simulator to be a useful training tool, the operator must be able to see the virtual hands interact with the virtual controls. A good VR crane simulator will have this capability.|
|This web site is sponsored by GlobalSim, Inc. GlobalSim provides crane simulators for the maritime markets (Ship-to-Shore Quay Crane, Rubber Tyre Gantry, Rail Mounted Gantry, Ship Pedestal, Mobile Harbor Crane) and construction markets (Tower Crane, Mobile Lattice and Hydraulic Telescopic) as well as intermodal and custom crane simulators.|
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