Research On The Visual Simulation System Of Air Cushion Vehicle Simulator Based On EPX

As an Indispensable part of Air Cushion Vehicle(ACV)Simulator, the visual simulationsystem should veritably and intuitively display the navigation status of the ACV in virtualenvironment. So, this needs the reasonable distribution of the resources to build a visualsimulation system which Conform to the standard. This paper built a ACV visual simulationsystem according to the actual needs, and researched the collision detection technology andthe terrain-matching algorithm deeply to solve the practical problems in the process ofbuilding visual system.As to the terrain-matching algorithm, based on four points matching algorithm and usedsix points matching algorithm for reference, five points matching algorithm was used to makethe ACV match the terrain. The ACV was simplified as a rigid body. And five feature pointsinclude the barycenter were chosen to simplify the rigid body. It computed the five points’height value of the terrain separately, then chosen three to determine the pose plane of theACV. In this algorithm, the problem that the terrain may be incised by the ACV in four pointsmatching algorithm was solved. As to the match to the sea waves, three points matchingalgorithm was used as a simple way to solve this problem.As an important part of a visual simulation system, the collision detection shows itsimportance in real-time and facility, especially to a control simulator. According to thecharacteristics of collision detection of this visual system, the collision detection based on linewas adopted. A group of lines were assigned around the skirt of the ACV to fit the form of theskirt. This method makes it an easy way to eliminate the nonintersecting object pairs. When incollision, dichotomy was used to divide the line which was detected into two parts from themiddle point in time and rearrange. In order to confirm the suitable time of stopping thedividing, a threshold value was given. When dividing stopped, take the middle point of thelast line as the point that the collision happened. As to the response of collision, divide theACV into several areas. And then compute the area and the normal direction of everyincollision area. This makes the compute easy and reduced the load of the system.In order to simulate the sea waves, several kinds of sea spectra were analyzed. Andmodeling the sea waves based on sea spectra. At last, use the FFT transform to realize the wave model, and generate waves in time.