Papers by Keyword: Kinematic Simulation

Abstract: The paper proposes a mechanical study of the self-centering mechanism of the bipolar prosthesis. This represents the fundamental principle of the bipolar construction, and relays on the offset between the inner and outer center of rotations of the bipolar head. In the paper, the kinematical aspects of the construction were recorded and explained by using five different offset values and keeping constant the femoral head diameter and the acetabular diameter. The simulations were conducted by imposing to the femoral head a linear movement in the vertical direction, similar to a reaction force that occurs when an implanted patient stands up. Two initial conditions were used for each geometric offset: one ideal, no friction and another more realistic by implementing friction coefficients at the sliding interfaces.

Abstract: The accurate orientation of concentrated solar converters (e.g. solar parabolic dish, concentrated photovoltaic) requires small stepwise angular displacements at short intervals of time aiming to track accurately the sun. These tracking systems are usually operated, especially the elevation movement, by low speed linear actuators (LSLA) with special configuration. The main drawbacks of the known LSLA solutions refers to the high constructive complexity of the intermediate gear reducer and its relative low efficiency due to the high value of the kinematic ratio, required to harmonize high speed motors and low speed outputs. The paper presents a geometrical synthesis algorithm and kinematic simulations of a new LSLA variant, proposed by the authors, consisting of a classical electrical motor (AC or DC), a linkage reducer transmitting intermittently the motion to a final irreversible screw-nut transmission through backstopping clutches. Compared to the known solutions, the proposed actuator has the advantage of decreasing the structural, constructive and technological complexity of the intermediate gear reducer (between the motor and the irreversible screw-nut transmission) by replacing it with a linkage type speed reducer and backstopping clutches, achieving a fixed or adjustable high kinematic ratio.

Abstract: Contrapose the disadvantages of the traditional fire water branch stents, the paper developed a simple structure, safe and reliable, low labor intensity, and can adapt to the complex fire environment of portable fire water branch stents.This paper introduces the structure and working principle of fire water branch stents, and simulates analysis of the motion trajectory of fire water branch through the Pro/E and ADAMS.The results show that the portable fire water branch stents safe and reliable, can meet the demand of fire control.

Abstract: The planetary lapping is an effective method to improve the precision and efficiency, to obtain the ideal grinding trajectory by changing the planetary structure on the basis of the traditional abrasive mechanism. In order to grinding double plane of multi workpieces at the same time, first the design specific analyze the trajectory, Then, the planetary grinding structure is designed according to the processing requirements, and finally, the trajectory of the lapping is simulated by the kinematics and geometry, in order to verify its availability. The grinding machine is not only has a high machining accuracy and machining quality, but also is simultaneously used in the multiple workpieces having different cross-section within a certain size, in addition, it improves the processing efficiency and reduces processing costs. tables etc.

Abstract: Based on some kind of transfer robot, conduct virtual assembly and kinematic simulation analysis on transfer robot by using NX software, thus to instruct the practical assembly and control of the robot. Analyze the poor movement stability of robot, point out its flaws of inertial impact and short rigidity. Conduct structural analysis on the original model by using NX software, verify the analytical conclusions, and carry out structural optimization design on the model to improve the products structure.

Abstract: In order to make the paralyzed live on their own and return to the society to the most degree, mechanical exoskeleton technology is tried to applied in the field of auxiliary equipment. First, degrees of freedom and mechanical structure at the each joint of lower extremity exoskeleton was ascertained.Then a three dimensional modeling design for the lower extremity exoskeleton was carried out with SIEMENS NX8.0 and a walking gait on a flat for it was planned on MATLAB basing on inverted pendulum model.Finally the legs model was simulated on ADAMS.The result of the simulation was basically the same as planned gait which can better satisfy the requirement of human walking and can be used as reference for developping the physical prototype of lower extremity exoskeleton.

Abstract: In this paper, the history and present conditions of welding robot were summarized in domestic situation and foreign situation, the latest development in technology was discussed. According to the structure and motion features of welding robots, using the UG simulation techniques can help us to establish the virtual prototype model of the robot easily, which can achieve the movement of the whole system analysis, dynamic analysis and so on. In this paper, the result of the application ADAMS simulation software is that the simulation mode provide reference for optimize the structure and drive mode design. It also was provided a possible scheme for the final optimal design.

Abstract: Base on analyzing the design demand of the return system in the ball screws, combining the sine curve and the quintic parabola curve, this paper introduces a new type of curve for steel balls used in heavy load bearings. By computing and programming in Matlab, this paper gets the sine-quintic parabola curve and conducts the kinematic simulation based on it. The results show that the balls can get in and out of the return system continuously and cause low impulse force on the return system. The highest impulse force happens when the balls access the return system. All this results can contribute for the later design and research of the internal circulation return system.

Abstract: Elliptic family gears are commonly used in non-circular gears, which include elliptic gear, high-order gear, elliptic deformed gear and high-order deformed gear, thereinto high-order deformed gear can include the elliptic family gears through adjust its order and deformed coefficient. Because non-circular gear has different tooth profile in different position of pitch curve and there is difference in the left and right tooth profile of the same gear tooth, thus the CAD modeling of non-circular gear is difficult for these characteristics; but the precise model of non-circular gear has important significance to the realization of numerical control machining, kinematic simulation and relevant mechanical analysis. This paper deduce the corresponding pure rolling mathematical model based on the pure rolling contact theory that cylindrical gear and non-circular gear mesh in the end face, and realize the CAD modeling of non-circular straight and helical gears by letting the cylindrical gear and non-circular gear make solid geometry operation, which is suitable for pitch curve with convex and concave. The non-circular gear shaping methods with equal polar and equal arc length are simulated by setting different discrete polar angles, and the transmission ratio curve and the angular acceleration curve of driven gear are get through the kinematic simulation of gear pair, which realize the transmission performance analysis of elliptic family gear pair. The above research results can be applied to the modeling and kinematic performance analysis of other non-circular gears.

Abstract: To study the globoidal indexing cams parametric design, this paper introduced three kinds of its parametric modeling method.That was offset surfaces method , direct modeling method and "point - curve - surface" method. Then modeled the globoidal indexing cams which had the same parameters and specifications by three parametric methods and Pro/Engineer.Meanwhile, used curvature comb command in Pro/Engineer to conduct the curvature analysis of indexing segment of cam profile. At last, conducted the indexing mechanisms kinematic simulation by ADAMS. From the characteristics of these three parametric methods and the result of cam profiles curvature analysis, this paper explains the reason of jitter acceleration in the simulation results.