State Estimation and Parameter Identification Method for Dual-rate System based on Improved Kalman Prediction

Panfeng Huang,Zhenyu Lu,Zhengxiong Liu 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.4

For the dual-rate system, such as the process of space teleoperation whose control signals is partlydetermined by delayed feedback states, the state values and system parameters are coupled and influenced eachother, which are hard to be estimated simultaneously. In this paper, we propose a novel method for this problem. Firstly, considering the asynchronism of the input and output sampling signals, an auxiliary model is modeled as amedium to the state and output functions. Secondly, the Kalman prediction algorithm is improved to estimate thestate values at output signals of the dual-rate system. The general step is using the output estimated errors in originaland auxiliary systems to modify the estimated state values of the auxiliary model, and then the unknown state valuesin original system is defined by the ones in auxiliary model. Based on improved Kalman algorithm and hierarchicalidentification algorithm, we present the detailed procedures of state estimation and parameter identification methodfor the dual-rate system. The processes of state estimation and parameter identification are calculated and modifiedalternately. Finally, the simulation results reveal that the state and parameters both approach to the real values andthe state values converge faster than the parameters.

Global Minimum-Jerk Trajectory Planning of Space Manipulator

Panfeng Huang,Yangsheng Xu,Bin Liang 대한전기학회 2006 International Journal of Control, Automation, and Vol.4 No.4

A novel approach based on genetic algorithms (GA) is developed to find a global minimum-jerk trajectory of a space robotic manipulator in joint space. The jerk, the third derivative of position of desired joint trajectory, adversely affects the efficiency of the control algorithms and stabilization of whole space robot system and therefore should be minimized. On the other hand, the importance of minimizing the jerk is to reduce the vibrations of manipulator. In this formulation, a global genetic-approach determines the trajectory by minimizing the maximum jerk in joint space. The planning procedure is performed with respect to all constraints, such as joint angle constraints, joint velocity constraints, joint angular acceleration and torque constraints, and so on. We use an genetic algorithm to search the optimal joint inter-knot parameters in order to realize the minimum jerk. These joint inter-knot parameters mainly include joint angle and joint angular velocities. The simulation result shows that GA-based minimum-jerk trajectory planning method has satisfactory performance and real significance in engineering.

Enhanced Transparency Dual-user Shared Control Teleoperation Architecture with Multiple Adaptive Dominance Factors

Zhenyu Lu,Panfeng Huang,Pei Dai,Zhengxiong Liu,Zhongjie Meng 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.5

In traditional dual-user shared control teleoperation, the users’ operational transparency is influenced bythe dominance factora. Especially when a = 1 and a = 0 the trainer or trainee cannot receive any informationform the slave side. For enlarging the control flexibility and enhancing the system transparency, a novel methodwith multiple adaptive dominance factors is proposed in this paper. An ideal application of this method is on-lineoperation and supervision. The supervisor and operator can adjust the factors and switch the operation roles andstates freely. Once the slave robot handled by the operator diverges from the planned path, the dominance factorswill change adaptive to limit the operator’s movement. The adaptive principles are concluded from the dynamicperformance measured by the measuring functions. The conclusions suggest that the varying range of the systemdynamic performance is wider than the traditional method. In addition, considering the time delays between theslave and master sides, we proved the system stability conditions covering all the range of dominance factors. Finally, we make a discussion of the applying area of the novel shared control architecture.

Detecting Graspable Rectangles of Objects in Robotic Grasping

Lu Chen,Panfeng Huang,Yuanhao Li,Zhongjie Meng 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.5

Most convolutional neural network based grasp detection methods evaluate the predicted grasp by computing its overlap with the selected ground truth grasp. But for typical grasp datasets, not all graspable examples are labelled as ground truths. Hence, directly back propagating the generated loss during training could not fully reveal the graspable ability of the predicted grasp. In this paper, we integrate the grasp mapping mechanism with the convolutional neural network, and propose a multi-scale, multi-grasp detection model. First, we connect each labeled grasp and refine them by discarding inconsistent and redundant connections to form the grasp path. Then, the predicted grasp is mapped to the grasp path and the error between them is used for back-propagation as well as grasp evaluation. Last, they are combined into the multi-grasp detection framework to detect grasps with efficiency. Experimental results both on Cornell Grasping Dataset and real-world robotic grasping system verify the effectiveness of our proposed method. In addition, its detection accuracy keeps relatively stable even in the circumstance ofhigh Jaccard threshold.

Coordinated Control Method of Space-tethered Robot System for Tracking Optimal Trajectory

Xiudong Xu,Panfeng Huang 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.1

Space-tethered robot system is a new kind of space robot, which consists of a robot platform, space tether, and operation robot. This paper presents the coordinated control method in order to save thruster fuel of operation robot in the process of tracking the optimal approach trajectory. First, the optimal approach trajectory of an operation robot is designed using the Gauss pseudospectral method, which resulted in continuous optimal control force using the Lagrange interpolation scheme. The optimal control force is optimized and distributed to space tether and thrusters through simulated annealing algorithm in discrete points, which minimized fuel consumption of thrusters. The distributive continuous force is obtained via cubic polynomial fitting of optimal distributive force in 0.1s discrete time point. To tracking the optimal trajectory, Fuzzy Proportional-Derivative controller is designed with the help of optimal distribution force which come from optimization model. Simultaneously, the relative attitude of the operation robot is stabilized using attitude time-delay algorithm through the reaction wheels. Numerical results are presented, demonstrating the validity of saving thruster fuel and well performance in tracking the optimal trajectory.

Decentralized Multiple Control for DC Microgrid with Hybrid Energy Storage

Li Xin,Zheng Taoyin,Guo Panfeng,Huang Jianan,Li Xinyu,Xiong Wei 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

For a microgrid with hybrid energy storage system , unreasonable power distribution, significant voltage deviation and state-of-charge (SOC) violation are major issues. Conventionally, they are achieved by introducing communication into centralized control or distributed control. This paper proposes a decentralized multiple control to enhance the performance of the system. A low-pass filter based on droop control is applied to battery energy storage system (BESS), and a low-pass difference filter based on proportional-integral (PI) voltage regulation is employed for supercapacitor (SC). The cooperation between them realizes power distribution, in which the average power is compensated by BESS and the high-frequency fluctuation is suppressed by SC. Meanwhile, the voltage deviation is diminished through mode re-division. Considering the SOC imbalance of BESSs and SOC violation of SC, current correction and voltage compensation methods based on local information are proposed to optimize the current sharing of BESSs and ensure the availability of SC, respectively. The advantage of voltage compensation is that, the SC is still available in process of SOC recovery. The simulation model is established on the MATLAB/Simulink environment and the feasibility of proposed strategy is verified by simulation analysis in different scenarios.