A Practical Control Scheme for Autonomous Capture of Free-Flying Satellites by Space Robotic Manipulator based on Predictive Trajectory

2000 ◽  
Vol 12 (4) ◽  
pp. 385-393
Author(s):  
Hiroyuki Nagamatsu ◽  
◽  
Takashi Kubota ◽  
Ichiro Nakatani
Keyword(s):  
Control System ◽  
Time Delay ◽  
Degrees Of Freedom ◽  
Processing Time ◽  
Control Method ◽  
Poor Performance ◽  
Reference Trajectory ◽  
End Effector ◽  
Control Scheme ◽  
Target Satellite

This paper describes a practical control scheme for autonomous capture of a free-flying satellite in space using an onboard manipulator. In capturing a satellite, a reference trajectory for control of a manipulator is generated with a time delay due to the processing time of a target motion estimator and a manipulator controller. Consequently, the control system shows poor performance and the end-effector sometimes fails to capture the target satellite. To solve this problem, a control system is proposed that utilizes predictive trajectory based on target satellite dynamics. The validity and usefulness of the proposed control method are shown by computer simulations and experiments using a 3-D hardware simulator with 9 degrees of freedom.

scholarly journals Disturbance compensation-based output feedback adaptive control for shape memory alloy actuator system

2021 ◽  
Vol 18 (1) ◽  
pp. 172988142199399
Author(s):  
Xiaoguang Li ◽  
Bi Zhang ◽  
Daohui Zhang ◽  
Xingang Zhao ◽  
Jianda Han
Keyword(s):  
Adaptive Control ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Control Method ◽  
Control Law ◽  
Reference Trajectory ◽  
Disturbance Compensation ◽  
Comparison Results ◽  
Control Scheme ◽  
Actuator System

Shape memory alloy (SMA) has been utilized as the material of smart actuators due to the miniaturization and lightweight. However, the nonlinearity and hysteresis of SMA material seriously affect the precise control. In this article, a novel disturbance compensation-based adaptive control scheme is developed to improve the control performance of SMA actuator system. Firstly, the nominal model is constructed based on the physical process. Next, an estimator is developed to online update not only the unmeasured system states but also the total disturbance. Then, the novel adaptive controller, which is composed of the nominal control law and the compensation control law, is designed. Finally, the proposed scheme is evaluated in the SMA experimental setup. The comparison results have demonstrated that the proposed control method can track reference trajectory accurately, reject load variations and stochastic disturbances timely, and exhibit satisfactory robust stability. The proposed control scheme is system independent and has some potential in other types of SMA-actuated systems.

Independent wheel control system design for highly automated driving

2021 ◽  
pp. 095440702110065
Author(s):  
Shihuan Li ◽  
Lei Wang
Keyword(s):  
Control System ◽  
Control Method ◽  
Autonomous Driving ◽  
Control System Design ◽  
Steering Control ◽  
Automated Driving ◽  
Accuracy And Precision ◽  
Actual Observation ◽  
Control Scheme ◽  
Interference Measurement

For L4 and above autonomous driving levels, the automatic control system has been redundantly designed, and a new steering control method based on brake has been proposed; a new dual-track model has been established through multiple driving tests. The axle part of the model was improved, the accuracy of the transfer function of the model was verified again through acceleration-slide tests; a controller based on interference measurement was designed on the basis of the model, and the relationships between the controller parameters was discussed. Through the linearization of the controller, the robustness of uncertain automobile parameters is discussed; the control scheme is tested and verified through group driving test, and the results prove that the accuracy and precision of the controller meet the requirements, the robustness stability is good. Moreover, the predicted value of the model fits well with the actual observation value, the proposal of this method provides a new idea for avoiding car out of control.

scholarly journals Decoupling Adaptive Smith Prediction Model of Flatness Closed-Loop Control and Its Application

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 895
Author(s):  
Mingming Song ◽  
Hongmin Liu ◽  
Yanghuan Xu ◽  
Dongcheng Wang ◽  
Yangyang Huang
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Time Delay ◽  
Control Method ◽  
Delay System ◽  
Control Performance ◽  
Time Delay System ◽  
Single Loop ◽  
Flatness Control ◽  
Pure Time Delay

Flatness control system is characterized by multi-parameters, strong coupling, pure time delay, which complicate the establishment of an accurate mathematical model. Therefore, a control scheme that combines dynamic decoupling, PI (Proportion and Integral) control and adaptive Smith predictive compensation is proposed. To this end, a dynamic matrix is used to decouple the control system. A multivariable coupled pure time-delay system is transformed into several independent generalized single-loop pure time-delay systems. Then, a PI-adaptive Smith predictive controller is constructed for the decoupled generalized single-loop pure time-delay system. Simulations show that the scheme has a simple and feasible structure, and good control performance. When the mathematical model of the control system is inaccurate, the control performance of adaptive Smith control method is evidently better than that of the ordinary Smith control method. The model is successfully applied to the cold rolling production site through LabVIEW, and the control accuracy is within 5I. This study reveals a new solution to the problem of coupled pure time-delay in flatness control system.

A Stable Adaptive Control Method in Networked Control System

2011 ◽  
Vol 110-116 ◽  
pp. 4837-4844
Author(s):  
Yu Zhang ◽  
Peng Cheng ◽  
Teng Fei Yin
Keyword(s):  
Control System ◽  
Time Delay ◽  
Control Method ◽  
Fuzzy Controller ◽  
Sampling Period ◽  
Networked Control System ◽  
Network Control ◽  
Control Logic ◽  
Network Time ◽  
Long Time

In this paper it has made study on long time-delay network control system which is greater than one sampling period, it has made modeling on sensor node time drive, controller node and actuator node event-driven system The special question has been considered which was brought more than one sampling period delay, the fuzzy control logic has been applied in MATLAB to design an adaptive Fuzzy controller, when the network time delay changes the controller parameters can be adjusted dynamically, to make dynamic compensation on network time delay, and through simulation experiments to verify the algorithm effectiveness.

Pure Time Delay Analysis for Decentralized Networked Control Systems

2014 ◽  
Author(s):  
Ahmad F. Taha ◽  
Ahmed Elmahdi ◽  
Jitesh H. Panchal ◽  
Dengfeng Sun
Keyword(s):  
Control System ◽  
Time Delay ◽  
Control Systems ◽  
Decentralized Control ◽  
Control Method ◽  
Networked Control System ◽  
Networked Control ◽  
Space Representation ◽  
Global Dynamics ◽  
Pure Time Delay

The network disturbance effect can be considered as either a perturbation or as a pure time delay for the exchanged signals. The network-induced time delay is one of the main challenges when a network is inserted in the feedback loops of a control system. In this paper, our objective is to improve the behavior of a Networked Control System (NCS) by analyzing the time-delay given that the decentralized control design method is adopted. First, we review an observer-based control method for decentralized control systems. Second, we establish a map between the decentralized non-networked system, and the typical NCS state-space representation. The main idea the mapping is to put the Decentralized Networked Control System (DNCS) in a general form and then map the resulting system to the typical NCS form. Third, we derive the global dynamics of the DNCS. Fourth, an upper bound for the time-delay is derived that guarantees the stability of LTI DNCSs. Finally, we present a numerical example that illustrates the applicability of the derived bound.

scholarly journals The Positioning of the Electromechanical System Using Sliding Mode Control without a Reaching Phase

2020 ◽  
Author(s):  
Stefan Brock
Keyword(s):  
Control System ◽  
Control Method ◽  
Sliding Mode ◽  
Industrial Robots ◽  
Cnc Machine Tools ◽  
Artificial Satellites ◽  
Reference Trajectory ◽  
Sliding Surface ◽  
Cnc Machine ◽  
Correct Operation

Precise and fast position tracking is essential for the correct operation of many industrial robots and CNC machine tools. This subject is also important in the control of the mount of the astronomical telescope, especially for the tracking of artificial satellites. As system parameters can change, a control method that is robust to changes in parameters must be used. Such a method is the sliding control, which, however, ensures the robustness only after reaching the sliding surface. Therefore, a new method was proposed in the paper, which eliminates the phase of reaching the sliding surface. The method consists of using a reference trajectory generator and determining the generalized error in relation to this trajectory. The procedure for designing the control system is presented. Next, the proposed method was verified on the laboratory stand. The described control method provides a robust system operation and can be easily implemented in the control system.

scholarly journals Overlapping Decentralized Control Strategies of Building Structures’ Vibration with Time Delay Based on H∞ Control Algorithms under Seismic Excitation

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiaofang Kang ◽  
Jian Wu ◽  
Yewei Zhang ◽  
Guoliang Liu ◽  
Suhui Zhang ◽  
...  
Keyword(s):  
Control System ◽  
Time Delay ◽  
Vibration Control ◽  
Decentralized Control ◽  
Control Strategy ◽  
Control Algorithm ◽  
Control Method ◽  
Control Strategies ◽  
Linear Matrix ◽  
Feedback Gain

A decentralized control strategy can effectively solve the control problem of the large-scale time delayed structures. In this paper, combining the overlapping decentralized control method, linear matrix inequality (LMI) method, and H∞ control algorithm, overlapping decentralized H∞ control approach of the time delayed structures has been established. The feedback gain matrixes of all subsystems are obtained by this method based on genetic algorithm optimization tools and the specific goal of optimization control. The whole vibration control system of the time delayed structures is divided into a series of overlapping subsystems by overlapping decentralized control strategy. The feedback gain matrixes of each subsystem can be obtained by using H∞ control algorithm to calculate each subsystem. The vibration control of a twenty layers’ antiseismic steel structure Benchmark model was analyzed with the numerical method. The results show that the proposed method can be applied to control system with time delay. The overlapping decentralized control strategies acquire the similar control effects with that of the centralized control strategy. Moreover, the flexibility of the controller design has been enhanced by using overlapping decentralized control strategies.

Kinematics and Force Transmission Analysis of a Decoupled Remote Center of Motion Mechanism Based on Intersecting Planes

2020 ◽  
pp. 1-24
Author(s):  
Kaiyu Wu ◽  
Fan Zhang ◽  
Guohua Cui ◽  
Jing Sun ◽  
Minhua Zheng
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Final Part ◽  
Force Transmission ◽  
Transmission Performance ◽  
End Effector ◽  
Motion Mechanism ◽  
Control Scheme ◽  
Rotational Degrees Of Freedom

Abstract A decoupled mechanism based on intersecting planes that can be considered a parallel mechanism with two arms is presented in this paper. The end-effector is connected to the base through two planar serial arms. The new specific characteristics of novel mechanism allow the generation of a Remote Center of Motion (RCM) possessing two decoupled rotational degrees of freedom (DoF) and a tanslational DoF. Compared with the RCM mechanism based on intersecting planes proposed by Li et al, due to the decoupling characteristics of this mechanism make it has a simpler control scheme and a larger workspace. This mechanisms also eliminates the singularity inside its workspace that impairs the original mechanism. In the final part of the paper, through an analysis of the force transmission performance, we derive a method to adjust the length of the linkage to optimize its force transmission performance.

Visual Control of Robotic Manipulator Based on Artificial Neural Network

1991 ◽  
Vol 3 (5) ◽  
pp. 394-400 ◽  
Author(s):  
Hideki Hashimoto ◽  
◽  
Takashi Kubota ◽  
Motoo Sato ◽  
Fumio Harashima ◽  
...  
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Visual Information ◽  
Degrees Of Freedom ◽  
Robotic Manipulator ◽  
Inverse Kinematic ◽  
End Effector ◽  
Control Scheme ◽  
Neural Network System ◽  
Artificial Neural

This paper describes a control scheme for a robotic manipulator system which uses visual information to position and orientate the end-effector. In the scheme the position and the orientation of the target workpiece with respect to the base frame of the robot are assumed to be unknown, but the desired relative position and orientation of the end-effector to the target workpiece are given in advance. The control system directly integrates visual data into the servoing process without subdividing the process into determination of the position, orientation of the workpiece and inverse kinematic calculation. An artificial neural network system is used for determining the change in joint angles required in order to achieve the desired position and orientaion. The proposed system can control the robot so that it approach the desired position and orientaion from arbitary initial ones. Simulation for the robotic manipulator with six degrees of freedom is done. The validity and the effectiveness of the proposed control scheme are varified by computer simulations.

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