Tuanjie Li^1,*, Yan Zhang¹, Jiaxing Zhou¹

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.3, pp. 583-598, 2019, DOI:10.31614/cmes.2018.04891

Abstract In order to satisfy the high efficiency and high precision of collaborative robots, this work presents a novel trajectory planning method. First, in Cartesian space, a novel velocity look-ahead control algorithm and a cubic polynomial are combined to construct the end-effector trajectory of robots. Then, the joint trajectories can be obtained through the inverse kinematics. In order to improve the smoothness and stability in joint space, the joint trajectories are further adjusted based on the velocity look-ahead control algorithm and quintic B-spline. Finally, the proposed trajectory planning method is tested on a 4-DOF serial collaborative More >

Jiayu Lu¹, Siqin Chang^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.1, pp. 91-109, 2019, DOI:10.31614/cmes.2019.04190

Abstract In this paper, a trajectory planning-based energy-optimal method is proposed to reduce the energy consumption of novel electromagnetic valve train (EMVT). Firstly, an EMVT optimization model based on state equation was established. Then, the Gauss pseudospectral method (GPM) was used to plan energy-optimal trajectory. And a robust feedforward-feedback tracking controller based on inverse system method is proposed to track the energy-optimal trajectory. In order to verify the effectiveness of the energy-optimal trajectory, a test bench was established. Finally, co-simulations based on MATLAB Simulink and AVL Boost were carried out to illustrate the effect of energy-optimal More >

Chen Yu^∗, Qinmin Hong, Dezhong Yao, Hai Jin

Computer Systems Science and Engineering, Vol.33, No.2, pp. 87-94, 2018, DOI:10.32604/csse.2018.33.087

Abstract The rapid expansion of GPS-embedded devices has showed the emerging new look of location-based services, enabling such offerings as travel guide services and location-based social networks. One consequence is the accumulation of a rich supply of GPS trajectories, indicating individuals’ historical position. Based on these data, we aim to mine the hot route by using a collaborative tensor calculation method. We present an efficient trajectory data processing model for mining the hot route. In this paper, we rst model the individual’s trajectory log, extract sources and destinations, use map matching to get the corresponding road More >

Liu Duo-Neng^1,2, Hou Zhong-Xi¹, Guo Zheng¹, Yang Xi-Xiang¹, Gao Xian-Zhong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.6, pp. 531-565, 2016, DOI:10.3970/cmes.2016.111.531 - 01 March 2022

Abstract Dynamic soaring is a flight maneuver to exploit gradient wind field to extend endurance and traveling distance. Optimal trajectories for permissible wind conditions are generated for loitering dynamic soaring as well as for traveling patterns with a small unmanned aerial vehicle. The efficient direct collection approach based on the Runge-Kutta integrator is used to solve the optimization problem. The fast convergence of the optimization process leads to the potential for real-time applications. Based on the results of trajectory optimizations, the general permissible wind conditions which involve the allowable power law exponents and feasible reference wind… More >

B. J. Zhu^1,2, Z. X. Hou¹, X. Z. Wang³, Q. Y. Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.5, pp. 357-377, 2015, DOI:10.3970/cmes.2015.106.357

Abstract The paper presents a comprehensive study on the performance of long endurance and long distance trajectory optimization of engineless UAV in dynamic soaring. A dynamic model of engineless UAV in gradient wind field is developed. Long endurance and long distance trajectory optimization problems are modelled by non-linear optimal control equations. Two different boundary conditions are considered and results are compared: (i) open long endurance pattern, (ii) closed long endurance pattern, (iii) open long distance pattern. In patterns of (i) and (ii), the UAV return to original position with the maximum flying time in pattern (ii) More >

Yonghua Zhou¹ , Xun Yang¹ , Chao Mi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.6, pp. 415-437, 2013, DOI:10.3970/cmes.2013.090.415

Abstract High-speed train transportation is organized in a way of globally centralized planning and locally autonomous adjustment with the real-time known positions, speeds and other state information of trains. The hierarchical integration architecture composed of top, middle and bottom levels is proposed based on model predictive control (MPC) for the real-time scheduling and control. The middle-level trajectory configuration and tractive force setpoints play a critical role in fulfilling the top-level scheduling commands and guaranteeing the controllability of bottomlevel train operations. In the middle-level MPC-based train operation planning, the continuous cellular automaton model of train movements is… More >

David A. Rebuck, Robert B. Nadler, Kent T. Perry

Canadian Journal of Urology, Vol.19, No.1, pp. 6094-6099, 2012

Abstract Introduction: To assess the technical feasibility and safety of trajectory image-guided percutaneous renal cryoablation in a porcine model.
Materials and methods: Six pigs (12 kidneys) were utilized. Only the posterior and lateral regions of the kidneys were considered. A bone-anchored dynamic reference frame (DRF) was inserted into the iliac crest and the O-Arm and StealthStation TREON System (OASSTS, Medtronic, CO, USA) was used to acquire 3-dimensional (3D) imaging of the kidneys. A hand-held pointing device was crafted from a cryoablation needle (Galil Medical, MN, USA) and an optical reference frame. The hand-held pointer/cryoablation needle ("cryoprobe") was then… More >

E. Ferretti¹

CMES-Computer Modeling in Engineering & Sciences, Vol.54, No.3, pp. 253-282, 2009, DOI:10.3970/cmes.2009.054.253

Abstract In this study, the problem of finding the complete trajectory of propagation and the limiting load in plates with internal straight cracks is extended to the non-linear field. In particular, results concerning concrete plates in bi-axial tensile loading are shown. The concrete constitutive law adopted for this purpose is monotonic non-decreasing, as following according to previous studies of the author on monotonic mono-axial loading. The analysis is performed in a discrete form, by means of the Cell Method (CM). The aim of this study is both to test the new concrete constitutive law in biaxial More >