Study on Anti-Rollover of the Counterbalance Forklift Based on Extension Hierarchical Control

Xia Guang,Li Jiacheng,Tang Xiwen,Zhao Linfeng,Sun Baoqun 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.3

The anti-rollover control actuator of a counterbalance forklift is determined by analysing its structural characteristics and roll-over mechanism. An anti-rollover control strategy for counterbalance forklifts based on extension decision is proposed, and the anti-rollover extension hierarchical controller, including the upper-layer extension and lower-layer execution controls, is designed. The upper-layer extension controller divides the forklift anti-rollover control domain into three types, namely, classical domain, extension domain and non-domain, and determines the weight coefficient of the lower layer execution controller. The lower-layer execution controller receives the weight coefficient determined by the upper-layer extension controller, controls the weight distribution on the yaw rate and lateral acceleration controllers and executes the command to obtain the anti-rollover extension control of the counterbalance forklift. The European standard condition simulation and real vehicle test results show that the anti-rollover control strategy of the counterbalance forklift based on the extension decision can effectively reduce the forklift roll range under high-speed emergency steering conditions, prevent the forklift from rolling over and improve the stability and active safety of the counterbalance forklift.

Numerical investigation of the mixing process in a Twin Cam Mixer: Influence of triangular cam height-base ratio and eccentricity

Yu He,Xiwen Li,Jiecai Long,Baojun Shen,Zhibin Sun,Yili Yang,Xiaobin Zhan 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.3

The twin cam mixer (TCM), as a general-purpose mixer, shares many attributes in common with 3D industrial mixers, like the internal mixer. We investigated the mixing process in a 2D TCM with two identical isosceles triangular cams rotating at 0.5 rpm. A 2D numerical model coupled with the species transport model was employed to study the influence of cam height-base ratio and eccentricity qualitatively and quantitatively, and both were found to have a significant effect on the mixing behavior of the mixer. Furthermore, a dimensionless parameter, named the modified pressurization coefficient, is put forward to quantify the geometry of the mixer. The logarithmic relationship between the modified pressurization coefficient and the mixing quality was discovered and expected to provide new ideas for establishing the relationship between the geometric parameters of a mixer and its mixing performance.

Adaptive Fault-Tolerant Control Considering the Actuator Failure of Forklift Anti-Rollover System

Xia Guang,Li Tao,Tang Xiwen,Zhang Yang,Zhao Linfeng 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.3

An adaptive fault-tolerant anti-rollover fuzzy system is proposed to improve the anti-rollover performance of counterbalanced forklifts. Considering the actual control input, various unpredictable actuator failure models in the system are established. Based on the three degree-of-freedom (DOF) model of a counterbalanced forklift, an anti-rollover Takagi-Sugeno (T-S) fuzzy system is established. The stability of this anti-rollover system is analyzed to ensure its stability under specific control inputs and external disturbances. When the upper limits of actuator faults and disturbances are unknown, an adaptive fault-tolerant control method is designed to update the controller parameters. The sufficient conditions for the stability of the forklift anti-rollover system in the presence of actuator faults and external disturbances are given using the Lyapunov stability theory. Simulation and real vehicle tests based on MATLAB/Simulink show that the anti-rollover system with adaptive fault-tolerant control can reduce impacts effectively and quickly after the actuator fails, thereby improving the safety and reliability of the forklift.

Performance of VC Backed Ventures

Fuguang Huang,Xiwen Li,Lingsia Sun 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

Influence of venture capitalist share holding on venture"s performance has been controversial and one of academic focus. We examine the performance measures of companies listed on China"s SME market and compare the performance of VC backed ventures and non VC backed ventures. By using one way ANOVA test and matched sample test, we find that the differnces of performances of VC backed and non VC backed ventures are not significant. We also briefly analyze the institutional background of Chinese venture investment market and find that the phenomenon is related to the background to some extent. We conclude that venture capitals do not promote the performances of companies. The venture capitals show no roles of advice services and certification.

Anti-rollover of the counterbalanced forklift truck based on model predictive control

Guang Xia,Jiacheng Li,Xiwen Tang,Yang Zhang,Jinfang Hu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.5

To reduce the probability of a rollover accident of a forklift during high-speed steering, a hydraulic support cylinder is designed as an actuator to provide lateral support for the forklift. Aiming at the problem of judging the safety domain in the process of forklift driving, this paper proposes a strategy for dividing the forklift’s driving state on the basis of the zero moment point. The relationship between the zero moment point’s lateral component and the forklift’s support plane is used as the basis for division. The forklift rollover process is divided into a safe stage, a controllable danger stage, and a critical rollover stage. In the safe stage, the cylinder does not provide support force, and in the controllable danger stage, the cylinder support force is adjusted on the basis of the model predictive control algorithm to adjust the forklift. The cylinder can be controlled to provide maximum support for the body during the critical rollover phase. This method takes the three-degrees-of-freedom forklift anti-rollover model as the control object and serves as the basis for the calculation of the zero moment point. The anti-rollover controller is built in MATLAB/Simulink to simulate the European standard operating conditions and to verify the actual vehicle test. Results show that the predictive control of the forklift anti-rollover model based on the zero moment point can effectively improve the body attitude of the forklift during high-speed steering and prevent the forklift from rolling over.

Robust Adaptive Sliding‑Mode Control for Permanent Magnet Spherical Actuator with Uncertainty Using Dynamic Surface Approach

Yan Wen,Guoli Li,Qunjing Wang,Xiwen Guo 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.6

This paper presents a position tracking control method for a three degree-of-freedom permanent magnet spherical actuator (PMSA). The control method is designed based on a dynamic model of the PMSA with uncertainties including modelling errors and external disturbance. Sliding-mode surface are adopted to restrain and eliminate the efect of external disturbances. To compensate modelling errors, an adaptive law is employed to estimate unknown model parameters so that model information can be updated in real time. By the use of dynamic surface approach, three frst-order flters are introduced to avoid the explosion of derivative terms caused by traditional adaptive backstepping approach. The stability of the closed-loop system using the proposed controller is confrmed through Lyapunov theorem. The test bench consisted of the prototype of PMSA, the host computer, the current controller and the orientation detection device is established for experiments. Simulation and experimental results are provided to validate efectiveness of the proposed method.

Analysis of the extrusion pressure of a cylindrical extruder for extruding highly viscous fluids

Zhibin Sun,Baojun Shen,Yu He,Jiecai Long,Xiaobin Zhan,Yujin Li,Xiwen Li 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10

Extrusion pressure is crucial for the security and performance of a cylindrical extruder during the extrusion process. In this study, a validated CFD model was adopted to evaluate the relationship between the extrusion velocity, fluid viscosity, and the extrusion pressure of a cylindrical extruder while extruding highly viscous fluids. The simulated and experimental results of the extrusion pressure and velocity profiles show good agreement. This study reveals that extrusion pressure evolution can be divided into two stages during the extrusion process. At stage I, the distance between the ram and the bottom of the vessel (liquid height) is greater than the critical height and the extrusion pressure remains almost constant. At stage II, the distance is less than the critical height and the extrusion pressure increases exponentially. The results indicate that an increase in extrusion velocity and fluid viscosity leads to a linear increase in the extrusion pressure at stage I. Furthermore, by introducing a pressure number, Np, and a pressurerelated Reynolds number, Rep, a novel correlation of the extrusion pressure with the extrusion velocity, viscosity of highly viscous fluids and liquid height has been developed.

Computational fluid dynamic analysis of mass transfer and hydrodynamics in a planetary centrifugal bioreactor

Baojun Shen,Xiaobin Zhan,Yu He,Zhibin Sun,Jiecai Long,Yili Yang,Xiwen Li 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.7

Planetary centrifugal bioreactors are promising candidates for cell culture platforms since there is no pollution caused by stirring blades. In this work, the fluid structure in a planetary centrifugal bioreactor was investigated using the computational fluid dynamics (CFD) method. The effects of operating conditions on the oxygen transfer rate (OTR), mixing efficiency and shear environment of the bioreactor were studied with the revolution speed (N) ranging from 60 to 160 rpm and the rotation-to-revolution speed ratio (i) from 2 to 1. The results show that the volumetric mass transfer coefficient (kLa), turbulence intensity, volumetric power consumption, and shear stress increase along with the increase of the revolution and rotation speeds. Furthermore, the rotation in the opposite direction to the revolution is beneficial to the performance of the bioreactor. The planetary centrifugal bioreactor has a higher kLa of 50- 200/h and a lower average shear stress of 0.01-0.05 Pa in comparison with conventional stirred tank bioreactors, which makes it suitable for biological culture of oxygen-consuming cells and shear-sensitive cells.

Pyrotinib Combined with Vinorelbine in Patients with Previously Treated HER2-Positive Metastatic Breast Cancer: A Multicenter, Single-arm, Prospective Study

Kuikui Jiang,Ruoxi Hong,Wen Xia,Qianyi Lu,Liang Li,Jianhao Huang,Yanxia Shi,Zhongyu Yuan,Qiufan Zheng,Xin An,Cong Xue,Jiajia Huang,Xiwen Bi,Meiting Chen,Jingmin Zhang,Fei Xu,Shusen Wang 대한암학회 2024 Cancer Research and Treatment Vol.56 No.2

Purpose This study aims to evaluate the efficacy and safety of a new combination treatment of vinorelbine and pyrotinib in human epidermal growth factor receptor 2 (HER2)–positive metastatic breast cancer (MBC) and provide higher level evidence for clinical practice. Materials and Methods This was a prospective, single-arm, phase 2 trial conducted at three institutions in China. Patients with HER2-positive MBC, who had previously been treated with trastuzumab plus a taxane or trastuzumab plus pertuzumab combined with a chemotherapeutic agent, were enrolled between March 2020 and December 2021. All patients received pyrotinib 400 mg orally once daily plus vinorelbine 25 mg/m2 intravenously or 60-80 mg/m2 orally on day 1 and day 8 of 21-day cycle. The primary endpoint was progression-free survival (PFS), and the secondary endpoints included the objective response rate (ORR), disease control rate (DCR), overall survival, and safety. Results A total of 39 patients were enrolled. All patients had been pretreated with trastuzumab and 23.1% (n=9) of them had accepted trastuzumab plus pertuzumab. The median follow-up time was 16.3 months (95% confidence interval [CI], 5.3 to 27.2), and the median PFS was 6.4 months (95% CI, 4.0 to 8.8). The ORR was 43.6% (95% CI, 27.8% to 60.4%) and the DCR was 84.6% (95% CI, 69.5% to 94.1%). The median PFS of patients with versus without prior pertuzumab treatment was 4.6 and 8.3 months (p=0.017). The most common grade 3/4 adverse events were diarrhea (28.2%), neutrophil count decreased (15.4%), white blood cell count decreased (7.7%), vomiting (5.1%), and anemia (2.6%). Conclusion Pyrotinib plus vinorelbine showed promising efficacy and tolerable toxicity as second-line treatment in patients with HER2-positive MBC.