{"title":"Closed-loop Electromagnetic Actuation System for Magnetic Capsule Robot In a Large Scale","authors":"Xi Wang, Weilin Chen, Jiaole Wang, Shuang Song","doi":"10.1109/RCAR54675.2022.9872182","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872182","url":null,"abstract":"Accurate positioning and efficient movement are essential for magnetic capsule endoscopy, which has attracted more and more attention in recent years. However, moving in the desired trajectory often conflicts with precise positioning, as magnetic localization is only feasible in a small area near the sensors. In this paper, we proposed a closed-loop magnetic capsule robot actuation system, which can accomplish localization and actuation simultaneously on a large scale in the fluid environment of the human body. To achieve large-scale detection, electromagnetic coil and sensor array are fixed together on a 3-axis screw mobile platform. The distribution of magnetic field is analyzed with magnetic dipole model and rectangular electromagnetic coil model. Levenberg-Marquardt algorithm has been employed to estimate the position of the capsule robot by subtracting the actuation magnetic field. PI closed-loop controller with localization of the robot as feedback is applied in the system. Although the response speed of the system with the PI controller is not fast, it could perform well in stability, which is expected when the capsule is moving inside the human body. Two specific path following experiments were carried out to verify the performance of simultaneous localization and movement on a large scale. Results showed that the proposed system and method could work well.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115952495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Image-Based Visual Tracking Attitude Control Research on Small Video Satellites for Space Targets","authors":"Mengmeng Wang, Cai-zhi Fan, Chao Song","doi":"10.1109/RCAR54675.2022.9872236","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872236","url":null,"abstract":"Small video satellites are capable of conducting real-time continuous observation of space targets through attitude control and have broad application prospects. Since the traditional method of tracking based on location information needs the priori location information of the known target, effective tracking observation cannot be accomplished for non-cooperative targets. In this paper, we are going to design a visual tracking attitude control method for spatial targets based on image information, which can perform autonomous tracking observation for both cooperative and non-cooperative targets. Firstly, based on the principle of perspective projection, the internal and external parameter model of the camera is derived, and the conversion relationship between the inertial coordinate system and the pixel coordinate system of the on-board camera is established. Then the attitude dynamical model and kinematical model of the rigid satellite are given. The desired attitude and desired angular velocity of the small video satellite are derived based on the deviation information of the location coordinates of the target in the image plane projection point from the desired coordinates. Using the attitude error and angular velocity error as the control feedback quantity, the space target tracking PD controller is designed. The global stability of the closed-loop control system is proved using Barbalat theorem. The simulation results show that the proposed control method is effective for the visual tracking attitude control of space targets.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"132 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116755465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Variable Admittance Control for Robotic Contact Force Tracking in Dynamic Environment Based on Reinforcement Learning","authors":"Yufei Zhou, Tianyu Liu, Jingkai Cui, Yanhui Li, Mingchao Zhu","doi":"10.1109/RCAR54675.2022.9872292","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872292","url":null,"abstract":"The manipulators usually need to contact with the environment when executing the tasks. Maintaining the stability of the contact force between the manipulator end-effector and the environment is very crucial. However, constant admittance control method cannot maintain the stability of dynamic force tracking if the environment is uncalibrated. A variable admittance control algorithm based on reinforcement learning is proposed, which adjusts the damping parameter of admittance control through reinforcement learning agent. Through the simulation experiments, it is found that this method can maintain the stability of dynamic contact force tracking on a sloped surface and a sine surface when an estimation error of the environmental position exists. Compared with the traditional admittance control with constant coefficients, the adaptive admittance control algorithm performs better.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131757303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jun Yu Li, Yunshuang Zhang, Shuai Zhao, Chen Chao, Zhibin Du
{"title":"A Research on SOTIF of LKA based on STPA*","authors":"Jun Yu Li, Yunshuang Zhang, Shuai Zhao, Chen Chao, Zhibin Du","doi":"10.1109/RCAR54675.2022.9872242","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872242","url":null,"abstract":"Because of the safety risks caused by functional insufficiencies and performance limitations for automated vehicle, the Safety of The Intended Function (SOTIF) of the Lane Keep Assistance (LKA) system is studied based on the System-Theoretic Process Analysis (SPTA). The interaction of LKA system control model with driver, steering system, data acquisition system and other external environment is established. Based on the model, 7 kinds of Unsafe Control Actions (UCA) are identified, and the vehicle-level safety constrains are proposed. 20 triggering conditions are identified from the perspectives of functional insufficiency and misuse. Taking the severity and controllability as the evaluation indexes, the risk assessment of each trigger condition is carried out, and the improvement measures are put forward. This study comprehensively reveals the way to realize the intended functional safety of LKA, and lays a foundation for the formulation of the control strategy of autonomous vehicles.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115136261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Research on Axial Thermal Error Modeling Method of CNC Machine Tool Spindle Based on GA-ARMA*","authors":"Weicheng Lin, Ling Yin, Fei Zhang, Zewei He, Yu Chen, Wenhao Li, Yeming Song","doi":"10.1109/RCAR54675.2022.9872211","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872211","url":null,"abstract":"In order to improve the prediction accuracy of the thermal error model of CNC machine tools based on time series and reduce the time of model parameter identification, a time series thermal error modeling method based on intelligent optimization (GA-ARMA) was proposed. Using the reciprocal of the residual between the actual value and the predicted value as the genetic algorithm (GA) individual fitness value function, select the best individual obtained by evolution for several generations as the parameter of the ARMA model, quickly identify the parameters of the ARMA model, and establish the GA-ARMA spindle axial thermal error model. Through experiments to compare the prediction effects of the time series thermal error model based on intelligent optimization and the time series thermal error model, taking a certain type of three-axis CNC machine tool as the object, the prediction and comparison are carried out under different working conditions. The experimental results show that the model prediction average residual error reaches 1.28 $mu$m, and the modeling efficiency is improved by 544%.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116754374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Real-Time Human Falling Recognition via Spatial and Temporal Self-Attention Augmented Graph Convolutional Network","authors":"Jiayao Yuan, Chengju Liu, Chuangwei Liu, Liuyi Wang, Qi Chen","doi":"10.1109/RCAR54675.2022.9872276","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872276","url":null,"abstract":"Currently, the skeleton-based human action recognition (e.g. walking, sitting and falling down) has achieved great interest, because the skeleton graph is robust to complex background and illumination changes compared to images. In this paper, a complete solution to real-time falling recognition task for intelligent monitoring has been provided. First, a manually annotated skeleton dataset for falling down action recognition is published. Then, a real-time self-attention augmented graph convolutional network (ST-SAGCN) is proposed. The network contains two novel architectures: a spatial self-attention module and a temporal self-attention module, which can effectively learn intra-frame correlations between different body parts, and inter-frame correlations between different frames for each joint. Finally, extensive comparative experiments on the dataset have proven that the proposed model can achieve remarkable improvement on falling recognition task. When the model is deployed in intelligent monitoring system, it achieves an inference speed over 40 fps and meets the demand of practical applications.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123459605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tongtong Wang, R. Skulstad, Motoyasu Kanazawa, Guoyuan Li, V. Æsøy, Houxiang Zhang
{"title":"Physics-informed Data-driven Approach for Ship Docking Prediction","authors":"Tongtong Wang, R. Skulstad, Motoyasu Kanazawa, Guoyuan Li, V. Æsøy, Houxiang Zhang","doi":"10.1109/RCAR54675.2022.9872179","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872179","url":null,"abstract":"Accurate ship motion predictions play a vital role in supporting the decision-making process onboard. Generally, the ship dynamics are described by either a deterministic model derived from hydrodynamic principles or a black-box model learned from the observations. However, there are always cases in real life where the physics information is insufficient to develop a complete model, and the data quantity is also limited so that a data-driven model is away from expectation. For this obstacle, we propose a physics-data cooperative modeling approach based on a rough ship numerical model and a few operational data to enhance the model quality. The prior knowledge leveraged by the ship’s numerical model is integrated into the neural network as informative inputs, and the informed neural network calibrates the bias between model outcomes and actual states in principle. The proposed approach is validated in the real docking operation of a research vessel. Comparisons with both the purely hydrodynamic model and the data-driven model without physics informed are conducted. The results convinced that the physicsdata hybrid way yields a more accurate model with relaxed data requirements and less learning consumption.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123536424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qianyi Zhang, Dingye Yang, Lei Zhou, Zhengxi Hu, Jingtai Liu
{"title":"Trajectory Optimization on Safety, Length and Smoothness in Complex Environments with A Locally Trained and Globally Working Agent","authors":"Qianyi Zhang, Dingye Yang, Lei Zhou, Zhengxi Hu, Jingtai Liu","doi":"10.1109/RCAR54675.2022.9872237","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872237","url":null,"abstract":"Focused on the balance among safety, length, and smoothness, this paper proposes a novel model to train an agent with deep reinforcement learning to optimize trajectory in complex environments. Inspired by the human habit that first finds the shortest trajectory and then slightly optimizes safety and smoothness, State is initialized as a radical trajectory combined with local obstacle distribution. Action adjusts dangerous waypoints jointly. Reward penalizes length increase based on local smoothness change. Episode is early terminated to divide the whole problem into smaller ones, while reward assembles them back with a large amount of training data. This allows the agent to be trained locally and work globally to accelerate convergence. Performances in various scenarios demonstrate our method’s ability to balance safety, length, and smoothness. With the Markov property of the problem and our newly discovered mathematical property of B-spline, it adjusts waypoints under sub-grid map and can be generalized stably in various maps with dense obstacles.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121808840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Attitude control of ultra-low orbit satellite based on RBF neural network","authors":"Cai-zhi Fan, Shaoting Yu, Mengmeng Wang","doi":"10.1109/RCAR54675.2022.9872306","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872306","url":null,"abstract":"Ultra-low-orbit satellites have the advantages of high resolution, high efficiency and low launch costs; however, atmospheric drag may lead to complex external interference, and continuous orbital fuel consumption may cause uncertain satellite rotation inertia. In view of the attitude control problem of ultra-low orbit satellite, this paper puts forward an adaptive attitude control method based on RBF neural network, which approaches the ideal slip mode controller through RBF neural network and adjusts neural network parameters according to external disturbance adaptation. The paper is designed to prove the progressive stability of the controller by Lyapunov theory and carried out the simulation verification. The simulation results show that the designed attitude controller can effectively overcome the influence of uncertainty disturbance in the system and improve the accuracy of attitude control.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125745459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiaqing Zhang, Yong Zhang, Xiaodong Xu, Zhengqing Wu, Bin Ye
{"title":"An Autonomous Fire-fighting Robot with Ackermann Steering Mechanism","authors":"Jiaqing Zhang, Yong Zhang, Xiaodong Xu, Zhengqing Wu, Bin Ye","doi":"10.1109/RCAR54675.2022.9872258","DOIUrl":"https://doi.org/10.1109/RCAR54675.2022.9872258","url":null,"abstract":"Fire prevention and control has always been a topic of concern. Autonomous fire-fighting robot can replace firefighters to complete this dangerous task, which improves work efficiency and ensure work safety to a certain extent. Considering the large volume and weight of the fire-fighting robot, the Ackermann steering mechanism is suitable for the chassis of the robot. This paper focus on the design of the autonomous fire-fighting robot using the Ackermann type of chassis. According to the kinematics of the Ackermann structure, this paper use TEB local path planning algorithm and AMCL positioning algorithm to form a navigation framework to complete the autonomous positioning and navigation of the firefighting robot. At last, a simulation environment is built and the proposed scheme are well demonstrated by the experimental results.","PeriodicalId":304963,"journal":{"name":"2022 IEEE International Conference on Real-time Computing and Robotics (RCAR)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129262943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}