International Journal of Modelling, Identification and Control (12 papers in press)

Regular Issues

• Outlier detection algorithm based on deviation characteristic  
  by Yong Wang, Hongbin Wang, Pengcheng Sun, Xinliang Yin 
  Abstract: Outlier mining focuses on researching rare events through detection and analysis to dig out the valuable knowledge from them. In the static data set environment, the traditional LOF algorithm calculates the local outlier factor through the whole data set and requires a lot of computing time. To solve this problem, the algorithm divides the data space into grids, and calculates the local outlier factor based on the centroids of the grids. Since the grid number is less than data point number, the time complexity is obviously reduced under acceptable error. When the new data points are added, it can rapidly detect outliers. The contrast experiment results show that the new algorithm can reduce the computation time and improve the efficiency, while achieving comparable accuracy.
  Keywords: outlier detection; local outlier factor; deviation characteristic; fast LOF detection algorithm.
  
  
• Multi-discriminant feature fall detection algorithm based on joints  
  by Jimin Lai, Tonghui He 
  Abstract: Traditional fall detection algorithm is difficult to accurately extract and recognise human posture features, and easy to lose feature joints in the process of falling, resulting in low detection accuracy. Therefore, this paper proposes a multi-discriminant feature fall detection algorithm based on joints for nursing homes, medical rehabilitation centres and other places. Firstly, the initial features of human posture are obtained by the improved VGG-19 feature extraction model, and the initial position of the joints are obtained and coded by adding a residual module. Secondly, the decoder network is used to complete deconvolution and upsampling operations to achieve greater fine-grained resolution. Finally, the image pose refinement module is designed to analyse the relationship between different adjacent feature nodes, so as to realise the accurate identification of the node position when the fall occurs. On this basis, the corresponding fall discriminant characteristics are proposed to achieve the detection of the elderly fall action. The results show that the proposed algorithm is more accurate and effective than other traditional algorithms on some datasets.
  Keywords: fall detection; convolutional neural network; residual module.
  DOI: 10.1504/IJMIC.2023.10058394
   
  
• A new nonlinear PID controller design for a quadrotor system using teaching learning based optimisation algorithm  
  by Naima Bouhabza, Kara Kamel 
  Abstract: In this paper, a novel nonlinear proportional integral derivative controller based on the meta-heuristic optimisation technique is suggested. Owing to its straightforward implementation and structure, the proportional integral derivative controller is frequently employed in nonlinear system control. The teaching-learning-based optimisation algorithm, owing to its effectiveness, rapidity, and minimum initialisation parameter required, has gained the attention of a significant number of researchers. The quadrotor's actuation dynamics are controlled by nonlinear proportional integral derivative controllers. Moreover, under-actuated dynamics use the same controller mechanism. For each controller, six parameters are tuned using the integral time absolute error criteria. Through numerical simulation, the efficiency and control performance of the suggested scheme are proven and contrasted with those of the linear proportional integral derivative controller and the sliding mode control. The simulation research demonstrates the effectiveness and successful performance of the recommended control technique in terms of the transient response characteristics, tracking precision, and perturbation rejection.
  Keywords: quadrotor; teaching learning based optimisation; TLBO; optimisation; nonlinear PID control.
  DOI: 10.1504/IJMIC.2023.10058548
   
  
• A network control system for solving a speed coordination problem in a networked multi-motor drive  
  by Huang Jiexian, Suhaib Masroor, Zain Anwar Ali 
  Abstract: A control system connected to a sensor and actuator via communication network plays a pivotal role in a today's world. The problem of obtaining a consensus in a group of network-connected agents is one of the major areas of research in the network control systems. In industry, the multi-motor system is very demanding owing to a common load driven capacity, and cost saving. Coordinated speed plays a vital role to control the in-flight movement of multi-rotor UAV/drones, producing hovering, tilting or other necessary flight control movements. Thus, this study uses a leaderless multi-agent consensus model to achieve coordinated control of network-connected motor drives such that all the drives reach identical speeds. Moreover, this study also incorporates event-based control, so that the continuous time controller update can be avoided, thus offering energy saving. To ensure stable system design, the Lyapunov stability criterion is used, while the obtained design is simulated in MATLAB. The simulated results endorse the design concept, such that the system attains a consensus on motor speed along with energy saving.
  Keywords: network control system; NCS; leaderless multi-agent system; event-based consensus; networked multi-motor system.
  DOI: 10.1504/IJMIC.2023.10060804
   
  
• Detection with thermal imaging for packaging bag sealing based on knowledge transfer  
  by Shaoyu Tang, Lisheng Wei, Rui Wang, Pinggai Zhang 
  Abstract: To address the problem that most enterprises still use the manual packing bag seal detection method with low efficiency and poor stability, we propose an automatic detection method, which is based on knowledge transfer, to detect with thermal imaging for packaging bag sealing. Firstly, the thermal image of packaging bag seal is obtained by a thermal imager, random forest (RF) and support vector machine (SVM) are trained by small sample labels, and the two classifiers are fused to build an expert labelling system for labelling unlabelled samples; Then, the enhanced samples are created by combining the predicted samples and the labelled samples, and input into the fine-tuned VGG16 (visual geometry group) for training and testing; Finally, the experiment shows that the prediction accuracy of this method reaches 96.25%, which verifies the effectiveness and feasibility of the proposed method instead of manual detection method.
  Keywords: defect detection; expert labelling system; fine-tuned VGG16; knowledge transfer; thermal imaging.
  DOI: 10.1504/IJMIC.2024.10063841
   
  
• Automatic control method of AC asynchronous motor variable frequency speed control based on CEEMDAN-wavelet threshold  
  by Dandan Zhao, Xiaodong Zhang 
  Abstract: In order to overcome the problems of low response speed, poor control accuracy, and low baud rate in motor variable frequency speed control, an automatic control method for motor variable frequency speed control based on CEEMDAN wavelet threshold was designed. Firstly, collect motor signals and decompose them through CEEMDAN; Then, use wavelet threshold to remove high-frequency component signal noise; Finally, calculate the frequency of variable frequency speed control and use a current and speed dual closed-loop PI controller to control the motor speed and load torque, achieving automatic control of variable frequency speed control. The results show that after applying the method proposed in this paper, the minimum speed deviation is only 29 RPM, the minimum response speed is only 628 ms, and the control baud rate varies between 147 and 180 bps/h. This verifies the effectiveness of the motor variable frequency speed control method proposed in this paper.
  Keywords: AC asynchronous motor; variable frequency speed control; CEEMDAN decomposition; wavelet threshold; control frequency.
  DOI: 10.1504/IJMIC.2024.10064159
   
  
• Design of DTS training simulation system networking based on LoRaWAN protocol  
  by Weichen Long, Ruiqian Su, Haiyong Wu, Wei Wang, Lizhong Peng 
  Abstract: To improve the data transmission efficiency of the DTS training simulation system, this design is based on the LoRaWAN protocol to network the DTS training simulation system. First, analyse the characteristics of the LoRaWAN protocol, and design the networking architecture according to the LoRaWAN protocol. Second, select the optimal gateway of the DTS training simulation system networking by connecting the LoRaWAN protocol to the DTS training simulation system, and realize the load balance control of the network API LoRa gateway. Finally, use experiments to prove the progressiveness of the proposed networking method. The experimental results show that after applying the method proposed in this paper, the throughput of the DTS training simulation system is 183 bits/s, the data transmission delay is only 13ms, and the resource utilization rate can reach 96.5%, improving the system processing efficiency.
  Keywords: LoRaWAN protocol; optimal gateway selection; system networking design; load balance.
  DOI: 10.1504/IJMIC.2024.10064170
   
  
• Analysis and control for ideal variable transmission ratio characteristics of active front wheel steering  
  by Xiaojun He, Kun Yang, Yile Chang, Chao Ma, Wei Wang, Jie Wang 
  Abstract: The change law of ideal transmission ratio with vehicle speed and hand-wheel angle is studied based on constant gain of steady-state vehicle system. It is used to resolve the conflict between steering sensitivity at the low-speed segment and steering stability at the high-speed segment for the traditional vehicle. For preventing the sudden change of hand-wheel torque caused by the transmission ratio change, the ideal variable transmission ratio (VTR) law is fitted by the improved S-type function and optimised by particle swarm optimisation (PSO) algorithm. For improving driving stability of vehicle, the stability control strategy based on linear quadratic regulator (LQR) is studied based on the optimised ideal variable transmission ratio control law. The front wheel angle is decided by the vehicle stability control strategy, and then the AFS motor angle is obtained by the AFS calculation module to realise the active front wheel steering (AFS) control. The closed-loop driver-vehicle system is established. This system includes driver model, the vehicle dynamic model, AFS model and so on. The results indicate that the performance for the proposed controller is good in the front wheel steering angle control for the better tracking to desired vehicle state.
  Keywords: ideal variable transmission ratio; improved S-type function; particle swarm optimisation algorithm; linear quadratic regulator; LQR; active front wheel steering; AFS.
  DOI: 10.1504/IJMIC.2024.10064195
   
  
• Hybrid multi control for better drone stability  
  by Wassim Arfa, Chiraz Ben Jabeur, Yassine Faleh, Hassene Seddik 
  Abstract: This study posits that the PID controller, designed to uphold drone stability, encounters a timing issue that warrants further tuning and enhancement. The study conducts a performance evaluation of PID controller gains for drone angle control, with the objective of optimising them to bolster the drone’s speed, accuracy, and stability. To achieve this objective, a PID flight controller is proposed to manage the altitude dynamics of a UAV. The study’s methodology primarily involves a comparative analysis across three levels: initially utilising a single PID controller for all three angles, then employing two PID controllers for all three angles where one manages pitch and roll angles while the other handles Yaw angle and finally implementing three PID sub-controllers for each angle (pitch, roll, and yaw). The comparative analysis aims to pinpoint the most effective PID controller configuration that enhances stability, responsiveness, and accuracy during flight. In comparison to prior research, the suggested adaptive PID flight controller showcases innovation and efficacy in the field.
  Keywords: PID controller; drone; angle control; optimisation; simulation; stability.
  DOI: 10.1504/IJMIC.2024.10064246
   
  
• Online real-time prediction of propulsion speed for EPB shield machine by SSA-GRU  
  by Wenshuai Zhang, Xuanyu Liu 
  Abstract: Given the extremely complex working environment of the shield machine, precise control of the digging parameters is the guarantee for the shield operation's safety. Therefore, the paper presents a Sparrow search algorithm-gate recurrent unit (SSA-GRU) based online prediction approach for shield machine propulsion speed. Firstly, the construction data are correlated based on the Pearson correlation coefficient, to obtain the boring parameters that are highly correlated with the propulsion speed and are considered as input variables for prediction model. Secondly, SSA is utilised to find the optimal hyperparameters of model. Finally, a prediction model is established based on optimal hyperparameters found by SSA, which more precisely exploits the nonlinear relationship from input features with propulsion speed, and accurately predicts propulsion speed. Simulation findings demonstrate that SSA-GRU model can precisely predict propulsion speed, and the prediction performance is superior to that of other models, effectively maintaining the stability of the excavation surface.
  Keywords: sparrow search algorithm-gate recurrent unit; SSA-GRU; propulsion speed; online real-time prediction.
  DOI: 10.1504/IJMIC.2024.10064367
   
  
• Vibration control method of eight-bar stamping mechanism based on coupled backstepping method  
  by Jiangliu Deng 
  Abstract: A vibration control method based on coupling backstepping method is proposed for the coupled vibration problem generated by the vertical and torsional coupling system in the motion process of the eight bar stamping mechanism. Construct a kinematic model of an eight bar stamping mechanism from the perspectives of displacement, velocity, and acceleration. Construct a three degree of freedom vibration model for an eight bar stamping mechanism, and propose a coupled vibration control strategy based on the coupled backstepping method for different mass blocks in the vibration model. Design an output feedback controller and use the coupled backstepping method to couple and vertically control the upper crossbeam components, slider components, and base components of the eight bar stamping mechanism. The experimental results show that the vibration displacement and load speed tracking errors of the eight bar stamping mechanism under the control of this method are effectively controlled.
  Keywords: coupled backstepping; eight-bar stamping mechanism; vibration control; kinematic model; controller.
  DOI: 10.1504/IJMIC.2024.10064888
   
  
• Observer-based distributed cooperative control strategies for AC microgrids under false data injection attacks  
  by Yiwei Feng, Yuhong Meng 
  Abstract: In this paper, we focus on the false data injection (FDI) attack that violates the cooperative nature of AC microgrid distributed generators (DGs), resulting in an unstable dynamics of the system. In order to solve the above problems, we propose observer-based detection and resilient control strategy. Firstly, a commonly used AC microgrid model needs to be established, and an FDI attack independent of the data encrypted by the system needs to be designed based on the control structure of the microgrid, to illustrate the sufficient necessity of studying this attack. Then, based on the above system and attack model, an observer-based detection is designed in one part to observe the data at the attacked location and accurately differentiate between attacks and disturbances. An adaptive distributed resilience controller is designed in the other part to ensure that the frequency of the system can be kept in synchrony and recovered to the reference frequency under attack to curb system out-of-synchrony operation. Finally, the speed of convergence from the system frequency and the ability to recover to the reference frequency of the controller designed in this paper is verified by simulation comparison on a system with 4 DGs, which verifies that the control of the controller designed in this paper is better under different attacks.
  Keywords: AC microgrids; AC MGs; false data injection; FDI; attack; an adaptive distributed resilience controller.
  DOI: 10.1504/IJMIC.2024.10065056