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Environmental Adaptive Control of a Snake-like Robot With Variable Stiffness Actuators

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 745-751页

作者： Dong Zhang Hao Yuan zhengcai cao IEEE College of Information Science and Technology Beijing University of Chemical TechnologyBeijing 100029China

This work investigates adaptive stiffness control and motion optimization of a snake-like robot with variable stiffness actuators. The robot can vary its stiffness by controlling magnetorheological fluid(MRF) around actuators. In order to improve the robot's physical stability in complex environments, this work proposes an adaptive stiffness control strategy. This strategy is also useful for the robot to avoid disturbing caused by emergency situations such as collisions. In addition, to obtain optimal stiffness and reduce energy consumption, both torques of actuators and stiffness of the MRF braker are considered and optimized by using an evolutionary optimization algorithm. Simulations and experiments are conducted to verify the proposed adaptive stiffness control and optimization methods for a variable stiffness snake-like robots.

关键词： Adaptive control snake-like robot variable stiffness

Adaptive Trajectory Tracking Control for a Nonholonomic Mobile Robot

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Chinese Journal of Mechanical Engineering 2011年第4期24卷 546-552页

作者： cao zhengcai ZHAO Yingtao WU Qidi College of Information Science and Technology Beijing University of Chemical Technology Beijing 100029 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China CIMS Research Center Tongji University Shanghai 200092 China

As one of the core issues of the mobile robot motion control, trajectory tracking has received extensive attention. At present, the solution of the problem only takes kinematic or dynamic model into account separately, so that the presented strategy is difficult to realize satisfactory tracking quality in practical application. Considering the unknown parameters of two models, this paper presents an adaptive controller for solving the trajectory tracking problem of a mobile robot. Firstly, an adaptive kinematic controller utilized to generate the command of velocity is designed based on Backstepping method. Then, in order to make the real velocity of mobile robot reach the desired velocity asymptotically, a dynamic adaptive controller is proposed adopting reference model and Lyapunov stability theory. Finally, through simulating typical trajectories including circular trajectory, fold line and parabola trajectory in normal and perturbed cases, the results illustrate that the control scheme can solve the tracking problem effectively. The proposed control law, which can tune the kinematic and dynamic model parameters online and overcome external disturbances, provides a novel method for improving trajectory tracking performance of the mobile robot.

关键词： nonholonomic mobile robot trajectory tracking model reference adaptive

Robust Fault Detection and Isolation Based on Finite-frequency H__/H_∞ Unknown Input Observers and Zonotopic Threshold Analysis

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IEEE/CAA Journal of Automatica Sinica 2019年第3期6卷 750-759页

作者： Meng Zhou zhengcai cao Ye Wang IEEE the College of Information Science & Technology Beijing University of Chemical Technology at the College of Automation Harbin Engineering University

This work proposes a robust fault detection and isolation scheme for discrete-time systems subject to actuator faults,in which a bank of H_/H∞ fault detection unknown input observers(UIOs) and a zonotopic threshold analysis strategy are considered. In observer design, finite-frequency H_ index based on the generalized Kalman-Yakubovich-Popov lemma and H∞ technique are utilized to evaluate worst-case fault sensitivity and disturbance attenuation performance, respectively. The proposed H_/H∞ fault detection observers are designed to be insensitive to the corresponding actuator fault only, but sensitive to ***, to overcome the weakness of predefining threshold for FDI decision-making, this work proposes a zonotopic threshold analysis method to evaluate the generated residuals. The FDI decision-making relies on the evaluation with a dynamical zonotopic threshold. Finally, numerical simulations are provided to show the feasibility of the proposed scheme.

关键词： Fault detection and isolation finite-frequency domain H_/H∞ technique unknown input observer zonotopic threshold analysis

Vision-based Stabilization of Nonholonomic Mobile Robots by Integrating Sliding-mode Control and Adaptive Approach

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Chinese Journal of Mechanical Engineering 2013年第1期26卷 21-28页

作者： cao zhengcai YIN Longjie FU Yili College of Information Science and Technology Beijing University of Chemical Technology The State Key Laboratory of Robotics and Systems Harbin Institute of Technology

Vision-based pose stabilization of nonholonomic mobile robots has received extensive attention. At present, most of the solutions of the problem do not take the robot dynamics into account in the controller design, so that these controllers are difficult to realize satisfactory control in practical application. Besides, many of the approaches suffer from the initial speed and torque jump which are not practical in the real world. Considering the kinematics and dynamics, a two-stage visual controller for solving the stabilization problem of a mobile robot is presented, applying the integration of adaptive control, sliding-mode control, and neural dynamics. In the first stage, an adaptive kinematic stabilization controller utilized to generate the command of velocity is developed based on Lyapunov theory. In the second stage, adopting the sliding-mode control approach, a dynamic controller with a variable speed function used to reduce the chattering is designed, which is utilized to generate the command of torque to make the actual velocity of the mobile robot asymptotically reach the desired velocity. Furthermore, to handle the speed and torque jump problems, the neural dynamics model is integrated into the above mentioned controllers. The stability of the proposed control system is analyzed by using Lyapunov theory. Finally, the simulation of the control law is implemented in perturbed case, and the results show that the control scheme can solve the stabilization problem effectively. The proposed control law can solve the speed and torque jump problems, overcome external disturbances, and provide a new solution for the vision-based stabilization of the mobile robot.

关键词： nonholonomic mobile robots vision-based stabilization sliding-mode control adaptive control neural dynamics

A Performance Driven Lot Merging Method with Closed Loop Optimization for Semiconductor Wafer Fabrication

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Chinese Journal of Electronics 2017年第5期26卷 912-918页

作者： cao zhengcai HUANG Zhexiao LIU Min College of Information Science and Technology Beijing University of Chemical Technology Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Department of Automation Tsinghua University

This paper deals with lot merging problem in semiconductor wafer fabrication *** is the possibility to merge two or more partial lots into single lot if their subsequent process routes are the same,an improved lot merging method is presented by grouping lots belonging to different *** on job information extracted from the buffers,several bin packing and knapsack solving algorithms are used to determine which lots should be *** iterative improvement procedure is introduced for optimizing merging strategy through a heuristic algorithm with resetting the ready time of critical *** closed loop structure with global revision factor is built for minimizing the impact of uncertain events while balancing the different orders processing *** to a simulation semiconductor manufacturing fab,the proposed algorithm can reduce cycle time and tardiness compared with other methods currently.

关键词： Semiconductor wafer fabrication Lot merging Simulation Bin packing

Multi-Robot Collaborative Hunting in Cluttered Environments With Obstacle-Avoiding Voronoi Cells

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1643-1655页

作者： Meng Zhou Zihao Wang Jing Wang zhengcai cao the School of Electrical and Control Engineering North China University of TechnologyBeijing 100144China IEEE the College of Information Science and Technology Beijing University of Chemical TechnologyBeijing 100029China

This work proposes an online collaborative hunting strategy for multi-robot systems based on obstacle-avoiding Voronoi cells in a complex dynamic environment. This involves firstly designing the construction method using a support vector machine(SVM) based on the definition of buffered Voronoi cells(BVCs). Based on the safe collision-free region of the robots, the boundary weights between the robots and the obstacles are dynamically updated such that the robots are tangent to the buffered Voronoi safety areas without intersecting with the obstacles. Then, the robots are controlled to move within their own buffered Voronoi safety area to achieve collision-avoidance with other robots and obstacles. The next step involves proposing a hunting method that optimizes collaboration between the pursuers and evaders. Some hunting points are generated and distributed evenly around a circle. Next, the pursuers are assigned to match the optimal points based on the Hungarian ***, a hunting controller is designed to improve the containment capability and minimize containment time based on collision risk. Finally, simulation results have demonstrated that the proposed cooperative hunting method is more competitive in terms of time and travel distance.

关键词： Dynamic obstacle avoidance multi-robot collaborative hunting obstacle-avoiding Voronoi cells task allocation

Simultaneous Prediction for Multiple Key Performance Indicators in Semiconductor Wafer Fabrication

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Chinese Journal of Electronics 2016年第6期25卷 1159-1165页

作者： cao zhengcai LIU Xuelian HAO Jinghua LIU Min College of Information Science and Technology Beijing University of Chemical Technology Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University Department of Automation Tsinghua University

The prediction and key factors identification for lot Cycle time(CT) and Equipment utilization(EU) which remain the Key performance indicators(KPI)are vital for multi-objective optimization in semiconductor manufacturing industry. This paper proposes a prediction methodology which predicts CT and EU simultaneously and identifies their key factors. Bayesian neural network(BNN) is used to establish the simultaneous prediction model for Multiple key performance indicators(MKPI),and Bayes theorem is key solution in model complexity controlling. The closed-loop structure is built to keep the stability of MKPI prediction model and the weight analysis method is the basis of identifying the key factors for CT and EU. Compared with Artificial neural network(ANN)and Selective naive Bayesian classifier(SNBC), the simulation results of the prediction method of BNN are proved to be more feasible and effective. The prediction accuracy of BNN has been obviously improved than ANN and SNBC.

关键词： Prediction for MKPI Cycle time Equipment utilization BNN Key factors identification

基于改进灰狼优化算法的自动化立体仓库作业能量优化调度

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计算机集成制造系统 2020年第2期26卷 376-383页

作者：刘恺文曹政才北京化工大学信息科学与技术学院

针对带有截止时间约束的自动化立体仓库出入库作业调度问题,以调度过程中堆垛机能量消耗为优化目标建立数学模型,并引入相应的惩罚函数。对于入库货物,同时考虑定位存储和随机存储两种入库策略,采用一种最近邻货位选择策略对随机存储货... 详细信息

针对带有截止时间约束的自动化立体仓库出入库作业调度问题,以调度过程中堆垛机能量消耗为优化目标建立数学模型,并引入相应的惩罚函数。对于入库货物,同时考虑定位存储和随机存储两种入库策略,采用一种最近邻货位选择策略对随机存储货物进行合理货位分配。采用一种改进灰狼优化算法对问题进行求解,算法通过引入融合Lévy飞行的混合个体更新策略和多种群重组策略来增强算法的搜索能力。通过仿真实验验证了改进灰狼优化算法在求解自动化立体仓库出入库作业能量优化调度问题的有效性。

关键词：自动化立体仓库能量优化调度灰狼优化算法惩罚函数

融合代理模型和差分进化算法的并行机动态调度方法

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计算机集成制造系统 2017年第1期23卷 75-81页

作者：张嘉琦曹政才刘民北京化工大学信息科学与技术学院北京100029 清华大学自动化系北京100084

针对目前进化计算求解并行机动态调度中的局部搜索能力不足、计算周期长等问题,引入问题分解思想和估计评价策略,提出一种基于差分进化算法与代理模型相融合的快速求解方法。采用基于机器编码的差分进化算法对上层设备选择问题进行粗搜... 详细信息

针对目前进化计算求解并行机动态调度中的局部搜索能力不足、计算周期长等问题,引入问题分解思想和估计评价策略,提出一种基于差分进化算法与代理模型相融合的快速求解方法。采用基于机器编码的差分进化算法对上层设备选择问题进行粗搜索。分析下层单机问题的关键性特征,构建能够预测调度性能指标优劣的代理模型,利用估计近似值取代费时的精确求解,降低繁冗评价过程带来的计算代价。在最佳分配方案的指导下,基于工件编码和多变异策略的差分进化算法确定设备上工件加工的前后顺序,实现设备分配与工件排序两个决策层的同步优化。通过仿真实验表明,该方法优于传统的并行机求解方法,尤其对于大规模并行机调度问题的求解质量更好。

关键词：并行机调度差分进化算法代理模型同步优化