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1. Stability and energy-saving coordinated control strategy of six-wheel independent drive unmanned ground vehicle.

Author

Xu, Xiaojun, Chen, Guanpeng, Gao, Xue, Jiang, Yue, and Feng, Yikun

Subjects
REMOTELY piloted vehicles, LAGRANGIAN functions, ENERGY dissipation, PARETO optimum, ENERGY consumption, BRAKE systems
Abstract

During the operation of six-wheel independent drive unmanned ground vehicle (6WID UGV) in the field, the inconsistent tire contact characteristics and frequent steering maneuvers have led to increasingly prominent issues of tire excessive wear and lateral instability. Therefore, a coordinated hierarchical controller for 6WID UGV is proposed to ensure the stability of the steering process while reducing tire wear and motor energy consumption. First, a sliding mode controller (SMC) with an extended-state observer (ESO) is proposed for lateral stability control referencing the active disturbance rejection control (ADRC) technique, achieving fast response and robustness to uncertainty. Second, the lower controller constructs a Lagrangian function with tire slip energy loss and energy consumption as optimization objectives and allocates torque based on the Pareto optimal solution within the feasible domain given by the upper controller. Finally, the designed controller is tested under typical operating conditions. The results indicate that the designed coordinated controller has significant control performance and economic benefits in improving lateral stability and reducing energy loss. Compared with the torque distribution strategy based on tire vertical load, the tire slip energy is reduced by 44.8 % and 17.7 % in the process of traction/steering and braking/steering, respectively. In addition, the motor energy consumption and the friction braking energy loss are reduced by 12.1 % and 70.8 % respectively. • The hierarchical coordinated control strategy is proposed to maintain the stability with the minimum energy loss. • The extended state observer is used to eliminate the influence of uncertainty. • The torque distribution strategy is proposed to reduce tire slip energy loss and tire wear. [ABSTRACT FROM AUTHOR]

Published
2023
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2. Clinical significance of the cribriform pattern in invasive adenocarcinoma of the lung

Author

Zhang, Ruizhen, Hu, Guiming, Qiu, Jinhuan, Wu, Huifang, Fu, Wenjing, Feng, Yikun, Zhang, Min, Chen, Chen, Sun, Jianping, Zhang, Yan, and Ren, Jingli

Abstract

PurposeAccording to the WHO, the cribriform pattern is a subtype of acinar (Aci) predominance in invasive adenocarcinoma (ADC) of the lung. Recently, several studies have demonstrated poor prognosis in patients with cribriform predominance. This study was performed to examine the correlations of cribriform pattern with the clinicopathology, molecular features and prognosis in patients with invasive ADC.MethodsHistological subtypes were evaluated in 279 patients who underwent complete resection for invasive ADC. Patients of the Aci-predominant subtype were divided into two subgroups according to the percentage of cribriform cancer (≥5% vs <5%). Clinicopathological characteristics, overall survival (OS), disease-free survival (DFS) and molecular changes were compared. In addition, both OS and DFS were compared between patients with cribriform-predominant (n=33) and pure Aci-predominant (n=88) ADCs.ResultsA cribriform pattern was found in 111 (39.8%) cases and ranged from 5 % to 100 % of the total tumour volume (mean±SEM, 30%±2%). Of 117 patients with Aci predominance, 79 showed the cribriform pattern, while the remaining 38 did not. The cribriform pattern was associated with aggressive pathological behaviour, including advanced stages of cancer, nuclear atypia, mitoses, lymph node invasion, metastasis and larger tumour size. The subgroup with cribriform cancer (≥5%) had significantly poorer OS and DFS compared with the cribriform-negative (<5%) group. In addition, Cox multivariate analyses revealed that the cribriform pattern was an independent predictor of OS but not DFS. Moreover, OS was significantly lower in the cribriform-predominant group than in the Aci-predominant group.ConclusionThe cribriform pattern is associated with aggressive pathological behaviour and is an independent poor prognostic indicator in patients with Aci-predominant ADC of the lung.

Published
2019
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