scholarly journals Development of Sliding Mode Controller Based on Internal Model Controller for Higher Precision Electro-Optical Tracking System

Actuators ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 16
Author(s):  
Bing Zhang ◽  
Kang Nie ◽  
Xinglong Chen ◽  
Yao Mao
Keyword(s):  
Internal Model ◽  
Sliding Mode ◽  
Tracking System ◽  
Internal Model Control ◽  
Optical Tracking ◽  
Tracking Accuracy ◽  
Optical Tracking System ◽  
Resistance Torque ◽  
Model Control ◽  
Strong Robustness

The electro-optical tracking system (ETS) on moving platforms is affected by the vibration of the moving carrier, the wind resistance torque in motion, the uncertainty of mechanisms and the nonlinear friction between frames and other disturbances, which may lead to the instability of the electro-optical tracking platform. Sliding mode control (SMC) has strong robustness to system disturbances and unknown dynamic external signals, which can enhance the disturbance suppression ability of ETSs. However, the strong robustness of SMC requires greater switching gain, which causes serious chattering. At the same time, the tracking accuracy of SMC has room for further improvement. Therefore, in order to solve the chattering problem of SMC and improve the tracking accuracy of SMC, an SMC controller based on internal model control (IMC) is proposed. Compared with traditional SMC, the proposed method can be used to suppress the strongest disturbance with the smallest switching gain, effectively solving the chattering problem of the SMC, while improving the tracking accuracy of the system. In addition, to reduce the adverse influence of sensor noise on the control effect, lifting wavelet threshold de-noising is introduced into the control structure to further improve the tracking accuracy of the system. The simulation and experimental results verify the superiority of the proposed control method.

scholarly journals High Precision Optical Tracking System Based on near Infrared Trinocular Stereo Vision

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2528
Author(s):  
Songlin Bi ◽  
Yonggang Gu ◽  
Jiaqi Zou ◽  
Lianpo Wang ◽  
Chao Zhai ◽  
...  
Keyword(s):  
High Precision ◽  
Stereo Vision ◽  
Near Infrared ◽  
Nearest Neighbor ◽  
Tracking System ◽  
Optical Tracking ◽  
Tracking Accuracy ◽  
Optical Tracking System ◽  
Dynamic Tracking ◽  
Trinocular Stereo

A high precision optical tracking system (OTS) based on near infrared (NIR) trinocular stereo vision (TSV) is presented in this paper. Compared with the traditional OTS on the basis of binocular stereo vision (BSV), hardware and software are improved. In the hardware aspect, a NIR TSV platform is built, and a new active tool is designed. Imaging markers of the tool are uniform and complete with large measurement angle (>60°). In the software aspect, the deployment of extra camera brings high computational complexity. To reduce the computational burden, a fast nearest neighbor feature point extraction algorithm (FNNF) is proposed. The proposed method increases the speed of feature points extraction by hundreds of times over the traditional pixel-by-pixel searching method. The modified NIR multi-camera calibration method and 3D reconstruction algorithm further improve the tracking accuracy. Experimental results show that the calibration accuracy of the NIR camera can reach 0.02%, positioning accuracy of markers can reach 0.0240 mm, and dynamic tracking accuracy can reach 0.0938 mm. OTS can be adopted in high-precision dynamic tracking.

How to Synchronize and Register an Optical-Inertial Tracking System

2013 ◽  
Vol 332 ◽  
pp. 130-136
Author(s):  
Ali Soroush ◽  
Mohammad Akbar ◽  
Farzam Farahmand
Keyword(s):  
Time Synchronization ◽  
Tracking System ◽  
Optical Tracking ◽  
Least Mean Square ◽  
Tracking Accuracy ◽  
Optical Tracking System ◽  
Sensory Data ◽  
Spatial Registration ◽  
Using Data ◽  
Error Method

Multi-sensor tracking is widely used for augmentation of tracking accuracy using data fusion. A basic requirement for such applications is the real time temporal synchronization and spatial registration of two sensory data. In this study a new method for time and space coordination of two tracking sensor measurements has been presented. For spatial registration we used a body coordinate system and then applied the effect of the level arm. The time synchronization was done based on least mean square (LMS) error method. This method was implemented to synchronize the position and orientation of an object using Inertial ( IMU) and Optical (Optotrak) tracking systems. The results of synchronized data were validated with measurements of Optical tracking system and the mean error of synchronized Euler angles, were less than 0.28 degree.

scholarly journals Research of Sliding Mode Control in Electro-Optical Tracking System

2013 ◽  
Vol 756-759 ◽  
pp. 403-406 ◽  
Author(s):  
Zi Peng Guo ◽  
Chao Ming Xie ◽  
Yong Jun Xiao
Keyword(s):  
Sliding Mode Control ◽  
Pid Controller ◽  
Sliding Mode ◽  
Tracking System ◽  
Variable Structure ◽  
Mathematic Model ◽  
Optical Tracking ◽  
Communication Link ◽  
Optical Tracking System ◽  
Mode Control

as the foundation and critical part of the free Space optical communication, the electro-optical tracking system is a typical nonlinear system. However, the angular accuracy should be better than a few micro-radians to meet the requirement of the communication link construction between two terminals. To get more control precision, the mathematic model of the coarse pointing system is founded, and sliding mode variable structure controller with approach law is designed. Finally, the simulation is done separately for a typical PID controller and the variable structure controller. Simulation results are showed that the sliding mode control can finely control the attitude of coarse pointing system, and can get higher precision by contrasted to the conventional PID controller.

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