Papers by Keyword: Trajectory

Abstract: The study of tracking algorithm of moving objects is a key technique in computer vision; therefore, the work done by this thesis has important theoretical significance and wide practical value. An algorithm based on the improved three-frame-differencing is introduced in this paper. Firstly, three continuous edge images are obtained by edge extract from three continuous images, then, the motion information is detected with three-frame-differencing, finally, the target is extracted by threshold segmentation and morphology. The method is simple in calculation. The experimental results show that the strong robustness and can accurately detect the moving target. In addition, using the algorithm based on the characteristics of the objects can clearly record the object’s trajectory. Experiments show that the algorithm is effective and feasible in the motion object detection.

Abstract: This paper presents a real-time interpolation algorithm of the space trajectory which based on the theory of coordinate transform. The algorithm can solve the path planning problem of six-DOF robot. According to the actual movement state of robot, the algorithm can obtain some key points for the robot motion path by teaching. Then it can realize the dimensional random trajectory interpolation by coordinate transformation after building a suitable dimensional coordinate. Finally it can obtain the corresponding joint angle though the inverse kinematics solution. The experimental results show that this algorithm has a good rapidity and practicality, it suit for the six-DOF robot real-time trajectory interpolation, so it is worth promoting.

Abstract: The basic experiment and detailed simulations are carried out to study the aerodynamic characteristics of projectile with deflectable nose. The parameters of computation are revised on the basis of experimental data. Further simulations show that the influence of mach number and deflectable angle on drag, lift, pitching moment and flight trajectory. The drag coefficient increases firstly and then decreases with the change of mach number, while drag coefficient and pitching moment coefficient grows exponentially. It can be seen that the ratio of lift to drag increases consistently, which means the aerodynamic efficiency of projectile would be improved with the increase of deflectable angle and mach number. The range is influenced by the start time of deflection. For the projectile with deflectable angle 10, the maximum range can be obtained if the forehead deflects at 3s.

Abstract: A 3D finite element model was established using the software ANSYS to simulate the inclusions trajectories and residence time in refining TiAl alloys during PAM process. The results show that tungsten, molybdenum and niobium inclusions can be removed by the mushy region entrapment, and all of these particles which diameter is larger than 40μm are captured in the pool bottom. The residence time of inclusion depends on the particle density and size. The bigger the inclusion density or the lager the inclusion diameter, the shorter the residence will be. Moreover, the inclusions trajectories and residence time are influenced by the hydrodynamics of the melt. The buoyancy force and the drag force provided by melt drive the inclusion particles moving in the pool.

Abstract: In this paper, Newton's laws of motion and momentum theorem are the theoretical basis. The equations of motion in the vertical plane are the calculation basis. In order to get the ballistic and numerical solution of motion parameters of the missile, the Runge-Kutta method and matlab are used to solve the missile Trajectory. Firstly, this paper builds the trajectory model of missile in vertical plane. Secondly, this paper chooses missile control method. Thirdly, the Runge-Kutta method and matlab are used to verify the correctness. And to further analyze the law of motion parameters changed with time.

Abstract: Based on linear simplification method, the mathematical model of standard II missile and target is built. The command control equation and guidance law are introduced to compute the trajectory of standard II missile and targets. The interception of low flying target with standard II missile is modeled and simulated with computer program. It studied different situations that the velocity and height of target varies. The numerical simulation result is proposed and analyzed, which is meaningful for the research of anti-missile defense.

Abstract: In this paper, marine environment in Dagukou district of Tianjin port is analyzed and evaluated. Marine oil spill accident is an important source of petroleum hydrocarbon in marine waters. So the simulation and forecasting of influence scope and trajectory of oil spill is a key means to obtain the hazard of oil spill to environmental protection target. A multi-module coupled oil spill model is constructed for simulating the influence scope and trajectory of oil spill, based on the coupling of the hydrodynamic model and wind field data.

Abstract: Complex analytical method is employed to study the motion of a kind of mechanism. The angular velocities and the angular accelerations of the connecting rod and the rocker are deduced. The motion trajectory and linear velocity of a key point are also given. The results of the given example show the feasibility and the effectiveness of the method and conclusions here.

Abstract: Proposed a new index structure, named MG2R*, can efficiently store and retrieve the past, present and future positions of network-constrained moving objects. It is a two-tier structure. The upper is a MultiGrid-R*-Tree (MGRT for short) that is used to index the road network. The lower is a group of independent R*-Tree. Each R*-Tree is relative to a route in the road network, can index the spatiotemporal trajectory of the moving objects in the road. Moreover, moving objects query is implemented based on this index structure. It compared to other index structures for road-network-based moving objects, such as MON-Tree, the experimental results shown that the MG2R* can effectively improve the query performance of the spatio-temporal trajectory of network-constrained moving objects.

Abstract: Cool Launch project is an important launch mode of submarine launched missile, the water-exit trajectory characteristic of the missile in launching process becomes to research focus. Model of three dimensional water-exit trajectory of submarine launched missile was built based on dynamic mesh technique and simulation operation was carried out to obtain the characteristics of water-exit trajectory & attitude. The method adopted in the establishment of the model and the result has provided references to the research of water-exit trajectory.