http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Zilong Cheng (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
Semi-Proximal ADMM for Model Predictive Control Problem with Application to a UAV System
Zilong Cheng,Jun Ma,Xiaoxue Zhang,Tong Heng Lee 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10
A lasso model predictive control (MPC) problem solved by the alternative direction method of multipliers (ADMM) is investigated in this work. More specifically, a semi-proximal ADMM algorithm with Gauss-Seidel iterations is proposed to solve the lasso MPC problem with singular weighting matrices. It is well-known that the interior-point algorithm is an effective and efficient algorithm, which is commonly used to obtain the real-time solution to the MPC optimization problem. However, when the weighting matrices of the lasso MPC problem are singular, it is extremely challenging to solve the optimization problem by using the classical interior-point algorithm. In fact, in some special cases, the interior-point algorithm is entirely infeasible for solving the aforementioned problems. In the work here, our developments reveal that the proposed optimization methodology (a semi-proximal ADMM algorithm with Gauss-Seidel iterations) is much more advantageous compared to the interior-point algorithm in some specific cases, especially in the case where singular weighting matrices exist in the cost function. An MPC based tracking problem of an unmanned aerial vehicle (UAV) system is implemented to compare the performance of the proposed algorithm to the performance of the existing solver. The simulation result shows that with the proposed algorithm, higher accuracy and computational efficiency can be realized.
-
Data-Driven Quadratic Optimization for Tracking Problems with Application to a Tray Indexing System
Zilong Cheng,Jun Ma,Xiaocong Li,Xiaoxue Zhang,Tong Heng Lee 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10
Iterative Feedback Tuning (IFT) algorithm explores the correlation between the cost function and the parameters of the controller. It introduces one data-driven approach to derive the gradient of the cost function with respect to the controller parameters and provides an iterative numerical method for the controller parameters optimization. However, classical IFT algorithms require three experiments to be conducted at one iteration, and one special experiment is included in the three experiments. That means the reference signal is changed during the iteration because of the special experiment, which restricts the application of the IFT algorithm in many areas. Besides, in many process control applications with long duration, IFT algorithm is much more time-consuming than many other tuning algorithms. In this paper, a novel IFT algorithm is proposed. For each iteration, no special experiment is required, which means parameters of the controller can be tuned when the system is running normally. Simulation results on a tray indexing system demonstrate the high performance and applicability of this algorithm.
-
A Collision-Free Framework for Navigation of Nonholonomic Vehicle Systems
Xiaoxue Zhang,Jun Ma,Zilong Cheng,Tong Heng Lee 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10
The task of highly effective navigation is certainly one of the critical technologies of autonomous vehicles that have been widely investigated by researchers. In this paper, a navigation framework with path planning and tracking is presented, where a feasible and collision-free trajectory is generated for nonholonomic vehicle systems. In terms of path planning, an LQR-RRT<SUP>*</SUP> algorithm is applied to plan a path without collision. It is an optimal sampling-based planning algorithm with linear quadratic regulation-based heuristics, and able to tackle some rather complicated or underactuated dynamic systems. In order to improve the feasibility of the planned path and compensate for the deterioration of optimality due to sampling times, the approach is taken where a cubic spline path is additionally generated. The path tracking problem is formulated as a constrained optimization problem for the nonholonomic vehicle system, and then the required steering angle and acceleration is computed to avoid potential collisions. The results of the simulation experiments clearly demonstrate the effectiveness of the proposed navigation framework.
-
Xiaoxue Zhang,Jun Ma,Sunan Huang,Zilong Cheng,Tong Heng Lee 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10
Control of autonomous robots (ARs) is a hot topic over the past three decades, and motion planning is becoming one of the major challenges in AR control. Substantial works have been done for motion planning in 2-dimensional (2D) environments, but planning in 3D complex environments is still an open problem to be investigated. In this paper, we propose a trajectory planning method to plan a high-quality and safe trajectory in 3-dimensional (3D) environments with multiple obstacles. The proposed method is based on the integration of a global optimal 3D path planner with a local planner. First, a hierarchical path planning algorithm is used as a global path planner to compute a near-optimal path formed by a set of waypoints. Second, a local path trajectory planner is designed to track the path computed by the global path planner with multiple constraints of dynamics and environment satisfied. Finally, simulations are conducted to validate the effectiveness of the proposed trajectory generation approach subject to the constraints of robot physical limits and environmental requirements.
-
Meng Liu,Yilun Deng,Yajun Cheng,Zilong Hao,Simiao Wu,Ming Liu 연세대학교의과대학 2021 Yonsei medical journal Vol.62 No.7
Purpose: Plasma osmolality, a marker of dehydration, is associated with cardiovascular mortality. We aimed to investigatewhether elevated plasma osmolality is associated with case fatality within 1 year after severe acute ischemic stroke. Materials and Methods: We included severe ischemic stroke patients (defined as National Institutes of Health Stroke Scale ≥15score) within 24 hours from symptom onset admitted to the Department of Neurology, West China Hospital between January 2017and June 2019. Admission plasma osmolality was calculated using the equation 1.86*(sodium+potassium)+1.15*glucose+urea+14. Elevated plasma osmolality was defined as plasma osmolality >296 mOsm/kg, indicating a state of dehydration. Study outcomesincluded 3-month and 1-year case fatalities. Multivariable logistic regression was performed to determine independent associationsbetween plasma osmolality and case fatalities at different time points. Results: A total of 265 patients with severe acute ischemic stroke were included. The mean age was 71.2±13.1 years, with 51.3%being males. Among the included patients, case fatalities were recorded for 31.7% (84/265) at 3 months and 39.6% (105/265) at1 year. Elevated plasma osmolality (dehydration) was associated with 3-month case fatality [odds ratio (OR) 1.98, 95% confidenceinterval (CI) 1.07–3.66, p=0.029], but not 1-year case fatality (OR 1.51, 95% CI 0.84–2.72, p=0.165), after full adjustment for confoundingfactors. Conclusion: Elevated plasma osmolality was independently associated with 3-month case fatality, but not 1-year case fatality, forsevere acute ischemic stroke.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
