Abstract. This paper proposes a spring efficiency assessment of a statically spring-balanced planar serial manipulator. The admissible spring configurations for the static balancing of planar serial manipulators without auxiliary links have been determined in the past. Gravity is balanced by the spring configuration systematically; however, the spring configuration also contains counter-effects between springs. Conceptually, with fewer counter-effects between springs, there is less burden on the spring system, which means that the springs are used more efficiently, and accordingly, the system would be safer, and its service life would be longer. In this study, the spring energy is represented in a quadratic form. The coefficients in a quadratic form represent the change in elastic energy with the relative position between links, which is named “elastic pseudo-stiffness”. Compared to the quadratic form of gravity energy, those elastic pseudo-stiffnesses for static balancing are regarded as positive contributions of a spring, while those that contain counter-effects are seen as negative ones. Spring efficiency is defined as the ratio of the elastic pseudo-stiffnesses, which has positive contributions for balancing to total elastic pseudo-stiffnesses. To use springs efficiently, the counter-effects, which are functions of spring parameters, need to be decreased, including spring stiffness and the attachment location of springs on links. A method to use spring efficiently by adjusting spring parameters is developed. Furthermore, it is found that, for a spring attached between adjacent links, the spring efficiency is 100 %, and the spring efficiency decreases while the number of joints over which the spring spans increases. In a spring manipulator system, the efficiency is negatively correlated to the payload. As an example, an efficiency assessment on a 3 degrees of freedom (DOF) manipulator is shown at the end.
{"title":"Spring efficiency assessment and efficient use of spring methods of statically balanced planar serial manipulators with revolute joints only","authors":"Chia-Wei Juang, Chi-Shiun Jhuang, Dar-Zen Chen","doi":"10.5194/ms-13-817-2022","DOIUrl":"https://doi.org/10.5194/ms-13-817-2022","url":null,"abstract":"Abstract. This paper proposes a spring efficiency assessment of a statically\u0000spring-balanced planar serial manipulator. The admissible spring configurations for the static balancing of planar serial manipulators without auxiliary links have been determined in the past. Gravity is balanced by the spring configuration systematically; however, the\u0000spring configuration also contains counter-effects between springs.\u0000Conceptually, with fewer counter-effects between springs, there is less\u0000burden on the spring system, which means that the springs are used more\u0000efficiently, and accordingly, the system would be safer, and its service life would be longer. In this study, the spring energy is represented in a\u0000quadratic form. The coefficients in a quadratic form represent the change in elastic energy with the relative position between links, which is named\u0000“elastic pseudo-stiffness”. Compared to the quadratic form of gravity\u0000energy, those elastic pseudo-stiffnesses for static balancing are regarded\u0000as positive contributions of a spring, while those that contain counter-effects are seen as negative ones. Spring efficiency is defined as the ratio of the elastic pseudo-stiffnesses, which has positive contributions for balancing to total elastic pseudo-stiffnesses. To use springs efficiently, the counter-effects, which are functions of spring parameters, need to be decreased, including spring stiffness and the attachment location of springs on links. A method to use spring efficiently by adjusting spring parameters is developed. Furthermore, it is found that, for a spring attached between adjacent links, the spring efficiency is 100 %, and the spring efficiency decreases while the number of joints over which the spring spans increases. In a spring manipulator system, the efficiency is negatively correlated to the payload. As an example, an efficiency assessment on a 3 degrees of freedom (DOF) manipulator is shown at the end.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42731602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. In metal milling, especially in the machining of low-stiffness workpieces, chatter is a key factor affecting many aspects such as surface quality, machining efficiency, and tool life. In order to avoid chatter, a milling chatter identification method based on dynamic wavelet packet decomposition (WPD) is proposed from the perspective of signal processing. The dynamic characteristics of the system are obtained by a hammer test. Based on the principle that the chatter frequency will reach a peak value near the natural frequency of the system, the original milling force signal is decomposed by WPD, and the sub-signals containing rich chatter information are selected for signal reconstruction. After numerical analysis and spectrum comparison, the reconstruction scheme is proved to be robust. Then, the time–frequency domain image of the reconstructed signal and the Hilbert spectrum feature are compared and analyzed to identify the chatter. Finally, the validity and reliability of the proposed method for chatter recognition are verified by experiments.
{"title":"Milling chatter recognition based on dynamic and wavelet packet decomposition","authors":"M. Xie, Xinli Yu, Ze Ren, Yuqi Li","doi":"10.5194/ms-13-803-2022","DOIUrl":"https://doi.org/10.5194/ms-13-803-2022","url":null,"abstract":"Abstract. In metal milling, especially in the machining of low-stiffness workpieces, chatter is a key factor affecting many aspects such as surface quality, machining efficiency, and tool life. In order to avoid chatter, a milling chatter identification method based on dynamic wavelet packet decomposition (WPD) is proposed from the perspective of signal processing. The dynamic characteristics of the system are obtained by a hammer test. Based on the principle that the chatter frequency will reach a peak value near the natural frequency of the system, the original milling force signal is decomposed by WPD, and the sub-signals containing rich chatter information are selected for signal reconstruction. After numerical analysis and spectrum comparison, the reconstruction scheme is proved to be robust. Then, the time–frequency domain image of the reconstructed signal and the Hilbert spectrum feature are compared and analyzed to identify the chatter. Finally, the validity and reliability of the proposed method for chatter recognition are verified by experiments.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47177309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yang Zhang, Hsin-Te Wang, Jian-Liang Lin, Chin-Fei Huang, K. Hsiao
Abstract. The use of locks has a history of thousands of years. Barbed-spring padlocks are the typical locks used in ancient China and can be divided into three main types, namely open-keyhole, hidden-keyhole, and blocked-keyhole padlocks. Since the mechanical structures of padlocks differ in terms of the opening process, they are reconfigurable mechanisms. With the combinations and changes of springs, keys, and keyholes, the padlocks have a variety of different unlocking methods which provide higher security. This work uses variable chains to analyze the structures of the blocked-keyhole padlocks. The representations of joints and chains are presented first. The structures and characteristics of representative barbed-spring padlocks are introduced. Six examples are provided to demonstrate the opening processes of blocked-keyhole padlocks. The result shows that it is a useful tool to realize the structural difference in the padlocks during operation.
{"title":"Structural analysis of traditional Chinese blocked-keyhole padlocks","authors":"Yang Zhang, Hsin-Te Wang, Jian-Liang Lin, Chin-Fei Huang, K. Hsiao","doi":"10.5194/ms-13-791-2022","DOIUrl":"https://doi.org/10.5194/ms-13-791-2022","url":null,"abstract":"Abstract. The use of locks has a history of thousands of years.\u0000Barbed-spring padlocks are the typical locks used in ancient China and can\u0000be divided into three main types, namely open-keyhole, hidden-keyhole, and\u0000blocked-keyhole padlocks. Since the mechanical structures of padlocks differ\u0000in terms of the opening process, they are reconfigurable mechanisms. With\u0000the combinations and changes of springs, keys, and keyholes, the padlocks\u0000have a variety of different unlocking methods which provide higher security.\u0000This work uses variable chains to analyze the structures of the\u0000blocked-keyhole padlocks. The representations of joints and chains are\u0000presented first. The structures and characteristics of representative\u0000barbed-spring padlocks are introduced. Six examples are provided to\u0000demonstrate the opening processes of blocked-keyhole padlocks. The result\u0000shows that it is a useful tool to realize the structural difference in the\u0000padlocks during operation.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46603702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. In this study, the authors propose a solutions map based on a telomere genetic algorithm (TGA) to improve the efficiency of 4R-linkage synthesis. First, the points on the center curve are obtained by using projective geometry, and those of the circle curve are obtained by vector elimination. Second, the definition of the linkage type, assessment of linkage performance, and a method to identify defects in the linkage are introduced. Third, the solutions map method is proposed that can map the linkage solutions obtained by all combinations of the points on the center curve to a 3D color-coded surface to represent the distribution of solutions with different attributes of linkages in the solution domain. Fourth, we use the proposed telomere operator and pseudo-histogram method to improve the traditional genetic algorithm, and expand the domain of solutions of the solutions map by using the TGA. Finally, the linkage synthesis software BurLink is developed based on the solutions map method. The results show that the TGA-based solutions map can quickly locate the required 4R-linkage solution in the solution domain, and provides engineers with more candidate solutions than traditional methods.
{"title":"TGA-based solutions map method for four-position synthesis of planar 4R linkage","authors":"Yehui Zhao, Lijun Xue, Guangming Wang, Fanglei Zou, Yue Song, Hongjiang Zhang","doi":"10.5194/ms-13-771-2022","DOIUrl":"https://doi.org/10.5194/ms-13-771-2022","url":null,"abstract":"Abstract. In this study, the authors propose a solutions map based on a telomere genetic algorithm (TGA) to improve the efficiency of 4R-linkage synthesis. First, the points on the center curve are obtained by using projective geometry, and those of the circle curve are obtained by vector elimination. Second, the definition of the linkage type, assessment of linkage performance, and a method to identify defects in the linkage are introduced. Third, the solutions map method is proposed that can map the linkage solutions obtained by all combinations of the points on the center curve to a 3D color-coded surface to represent the distribution of solutions with different attributes of linkages in the solution domain. Fourth, we use the proposed telomere operator and pseudo-histogram method to improve the traditional genetic algorithm, and expand the domain of solutions of the solutions map by using the TGA. Finally, the linkage synthesis software BurLink is developed based on the solutions map method. The results show that the TGA-based solutions map can quickly locate the required 4R-linkage solution in the solution domain, and provides engineers with more candidate solutions than traditional methods.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42125231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. To improve the control performance and dynamic response of the permanent magnet linear synchronous motor (PMLSM), a new sensorless control strategy of the PMLSM with the ultra-local model velocity control system is designed in this paper. Firstly, a model-free speed controller (MFSC) is constructed based on the principle of the ultra-local model. Meanwhile, based on the traditional sliding-mode observer (SMO), the back-electromotive force (BEMF) in the SMO is optimized by the model reference adaptive system (MRAS) to improve the observed speed information of the PMLSM. This control strategy improves the dynamic response ability and stability of the PMLSM system. Compared with the traditional motor control strategy, this design gets rid of the dependence on mechanical sensors, improves the dynamic response ability of the PMLSM, and reduces the velocity tracking error. The superiority of the control system is verified by simulation and experiment. Compared with the traditional dual proportional–integral (PI) control system and SMO, the new control strategy can improve the dynamic response performance of the PMLSM, enhance the stability, and track the speed information of the PMLSM with low error to reduce the chatter.
{"title":"A new sensorless control strategy of the PMLSM based on an ultra-local model velocity control system","authors":"Zheng Li, Zihao Zhang, Shengdi Feng, Jinsong Wang, Xiaoqiang Guo, Hexu Sun","doi":"10.5194/ms-13-761-2022","DOIUrl":"https://doi.org/10.5194/ms-13-761-2022","url":null,"abstract":"Abstract. To improve the control performance and dynamic response of the permanent magnet linear synchronous motor (PMLSM), a new sensorless control strategy of the PMLSM with the ultra-local model velocity control system is designed in this paper. Firstly, a model-free speed controller (MFSC) is constructed based on the principle of the ultra-local model. Meanwhile, based on the traditional sliding-mode observer (SMO), the back-electromotive force (BEMF) in the SMO is optimized by the model reference adaptive system (MRAS) to improve the observed speed information of the PMLSM. This control strategy improves the dynamic response ability and stability of the PMLSM system. Compared with the traditional motor control strategy, this design gets rid of the dependence on mechanical sensors, improves the dynamic response ability of the PMLSM, and reduces the velocity tracking error. The superiority of the control system is verified by simulation and experiment. Compared with the traditional dual proportional–integral (PI) control system and SMO, the new control strategy can improve the dynamic response performance of the PMLSM, enhance the stability, and track the speed information of the PMLSM with low error to reduce the chatter.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44143888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Similar to a space flying net, the capture field of the space netted pocket system is large and it can be applied to capture space non-cooperative targets flexibly. To maintain the stability of the space netted pocket system, eight inflatable rods are used as the supporting structure of the net surface. In this paper, a space netted pocket system is designed and modeled. Based on ANCF (absolute nodal coordinate formulation), a dynamic model of the complex space rope net system is established, and then an accurate model of closing rope considering the variable length is derived by introducing mass flow element. A double closed-loop sliding control method is designed to maintain the stable attitude of the service spacecraft. An extended observer is applied to estimate and compensate for the disturbances due to the uncertainty of the contact and flexibility in the system. Finally, the dynamic model and control method is verified through the simulation of the virtual prototype. Results show that the service spacecraft can maintain the attitude stability during target captured process and can track the desired angle during attitude maneuver. The flexible deformation and collision cause great disturbance to the service spacecraft, and the extended observer can improve the control accuracy from 10−3 to 10−4.
{"title":"Dynamic and sliding mode control of space netted pocket system capturing and attitude maneuver non-cooperative target","authors":"Chao Tang, Zhuoran Huang, Cheng Wei, Yang Zhao","doi":"10.5194/ms-13-751-2022","DOIUrl":"https://doi.org/10.5194/ms-13-751-2022","url":null,"abstract":"Abstract. Similar to a space flying net, the capture field of the space\u0000netted pocket system is large and it can be applied to capture space\u0000non-cooperative targets flexibly. To maintain the stability of the space\u0000netted pocket system, eight inflatable rods are used as the supporting\u0000structure of the net surface. In this paper, a space netted pocket system is\u0000designed and modeled. Based on ANCF (absolute nodal coordinate formulation),\u0000a dynamic model of the complex space rope net system is established, and\u0000then an accurate model of closing rope considering the variable length is\u0000derived by introducing mass flow element. A double closed-loop sliding\u0000control method is designed to maintain the stable attitude of the service\u0000spacecraft. An extended observer is applied to estimate and compensate for\u0000the disturbances due to the uncertainty of the contact and flexibility in\u0000the system. Finally, the dynamic model and control method is verified\u0000through the simulation of the virtual prototype. Results show that the\u0000service spacecraft can maintain the attitude stability during target\u0000captured process and can track the desired angle during attitude maneuver.\u0000The flexible deformation and collision cause great disturbance to the\u0000service spacecraft, and the extended observer can improve the control\u0000accuracy from 10−3 to 10−4.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44953893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The measurement of the road adhesion coefficient is of great significance for the vehicle active safety control system and is one of the key technologies for future autonomous driving. With a focus on the problems of interference uncertainty and system nonlinearity in the estimation of the road adhesion coefficient, this work adopts a vehicle model with 7 degrees of freedom (7-DOF) and the Dugoff tire model and uses these models to estimate the road adhesion coefficient in real time based on the particle filter (PF) algorithm. The estimations using the PF algorithm are verified by selecting typical working conditions, and they are compared with estimations using the unscented Kalman filter (UKF) algorithm. Simulation results show that the road adhesion coefficient estimator error based on the UKF algorithm is less than 7 %, whereas the road adhesion coefficient estimator error based on the PF algorithm is less than 0.1 %. Thus, compared with the UKF algorithm, the PF algorithm has a higher accuracy and control effect with respect to estimating the road adhesion coefficient under different road conditions. In order to verify the robustness of the road adhesion coefficient estimator, an automobile test platform based on a four-wheel-hub-motor car is built. According to the experimental results, the estimator based on the PF algorithm can realize the road surface identification with an error of less than 1 %, which verifies the feasibility and effectiveness of the algorithm with respect to estimating the road adhesion coefficient and shows good robustness.
{"title":"A comparative study of the unscented Kalman filter and particle filter estimation methods for the measurement of the road adhesion coefficient","authors":"Gengxin Qi, Xiao-bin Fan, Hao Li","doi":"10.5194/ms-13-735-2022","DOIUrl":"https://doi.org/10.5194/ms-13-735-2022","url":null,"abstract":"Abstract. The measurement of the road adhesion coefficient is of great\u0000significance for the vehicle active safety control system and is one of the key\u0000technologies for future autonomous driving. With a focus on the problems of\u0000interference uncertainty and system nonlinearity in the estimation of the road\u0000adhesion coefficient, this work adopts a vehicle\u0000model with 7 degrees of freedom (7-DOF) and the Dugoff tire model and uses these models to estimate the road adhesion\u0000coefficient in real time based on the particle filter (PF) algorithm. The\u0000estimations using the PF algorithm are verified by selecting typical\u0000working conditions, and they are compared with estimations using the unscented\u0000Kalman filter (UKF) algorithm. Simulation results show that the road adhesion\u0000coefficient estimator error based on the UKF algorithm is less than 7 %, whereas the road adhesion coefficient estimator error based on the PF algorithm is\u0000less than 0.1 %. Thus, compared with the UKF algorithm, the\u0000PF algorithm has a higher accuracy and control effect with respect to\u0000estimating the road adhesion coefficient under different road conditions. In order to\u0000verify the robustness of the road adhesion coefficient estimator, an\u0000automobile test platform based on a four-wheel-hub-motor car is built.\u0000According to the experimental results, the estimator based on the PF algorithm\u0000can realize the road surface identification with an error of less than 1 %,\u0000which verifies the feasibility and effectiveness of the algorithm with respect to\u0000estimating the road adhesion coefficient and shows good robustness.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42182944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yi-bin Zheng, Ming Liu, Baoshun Li, Guoqing Ma, M. Xiao
Abstract. In order to improve the structural performance of the out-of-pipe pipe-climbing robot, the out-of-pipe pipe-climbing robot is optimized. First, MATLAB software was used to optimize the structure and size of the robot according to the mathematical model of robot mechanics and size constraints. Then, SolidWorks software was used to establish a three-dimensional model of the robot which was then imported into ANSYS Workbench software. Static and modal analyses were then performed on key robot components under different working conditions and the topology optimization module in ANSYS Workbench was used to perform the topology optimization of the key components. Finally, the optimized components were statically analysed. By comparing the performance of the components before and after optimization, it was found the weights of the optimized frame and clamping arm were respectively reduced by 24 % and 20 %, and the maximum stress was respectively reduced by 46 % and 20 %. Ultimately, it was found that the stiffness and strength of the robot were improved and a lighter weight was achieved via optimization; thus, this work provides a reference for future research on pipe-climbing robots.
{"title":"Structural optimization of a pipe-climbing robot based on ANSYS","authors":"Yi-bin Zheng, Ming Liu, Baoshun Li, Guoqing Ma, M. Xiao","doi":"10.5194/ms-13-725-2022","DOIUrl":"https://doi.org/10.5194/ms-13-725-2022","url":null,"abstract":"Abstract. In order to improve the structural performance of the\u0000out-of-pipe pipe-climbing robot, the out-of-pipe pipe-climbing robot is\u0000optimized. First, MATLAB software was used to optimize the structure and\u0000size of the robot according to the mathematical model of robot mechanics and\u0000size constraints. Then, SolidWorks software was used to establish a\u0000three-dimensional model of the robot which was then imported into ANSYS\u0000Workbench software. Static and modal analyses were then performed on key\u0000robot components under different working conditions and the topology\u0000optimization module in ANSYS Workbench was used to perform the topology\u0000optimization of the key components. Finally, the optimized components were\u0000statically analysed. By comparing the performance of the components before\u0000and after optimization, it was found the weights of the optimized frame and\u0000clamping arm were respectively reduced by 24 % and 20 %, and the maximum\u0000stress was respectively reduced by 46 % and 20 %. Ultimately, it was\u0000found that the stiffness and strength of the robot were improved and a\u0000lighter weight was achieved via optimization; thus, this work provides a\u0000reference for future research on pipe-climbing robots.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44332801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. This paper will study a trajectory tracking control algorithm for electric vehicles based on a terminal sliding mode controller. First, a 3 degrees of freedom nonlinear vehicle model and a controller-oriented 2 degrees of freedom vehicle model are established. The preview time is adaptively adjusted based on the preview model. Then, the vehicle trajectory tracking controller, which uses the terminal sliding mode algorithm, is designed. The radial basis function (RBF) neural network algorithm is used to approximate the system variable parameters in the control model online. At the same time, fuzzy logic is used to control the gain parameters of the controller to reduce the chattering of the control system. Finally, the designed controller is verified by simulation. The maximum deviation of path tracking under different speeds is 0.6 m, and the target path can also be well followed under different road friction coefficients. The simulation results show that the controller designed in this paper can effectively carry out the vehicle trajectory tracking and lateral control and reduce the chattering to a certain extent.
{"title":"Autonomous vehicle trajectory tracking lateral control based on the terminal sliding mode control with radial basis function neural network and fuzzy logic algorithm","authors":"Binyu Wang, Y. Lei, Yao Fu, Xiao-hui Geng","doi":"10.5194/ms-13-713-2022","DOIUrl":"https://doi.org/10.5194/ms-13-713-2022","url":null,"abstract":"Abstract. This paper will study a trajectory tracking control algorithm for electric vehicles based on a terminal sliding mode controller. First, a 3 degrees of freedom nonlinear vehicle model and a controller-oriented 2 degrees of freedom vehicle model are established. The preview time is adaptively adjusted based on the preview model. Then, the vehicle trajectory tracking controller, which uses the terminal sliding mode algorithm, is designed. The radial basis function (RBF) neural network algorithm is used to approximate the system variable parameters in the control model online. At the same time, fuzzy logic is used to control the gain parameters of the controller to reduce the chattering of the control system. Finally, the designed controller is verified by simulation. The maximum deviation of path tracking under different speeds is 0.6 m, and the target path can also be well followed under different road friction coefficients. The simulation results show that the controller designed in this paper can effectively carry out the vehicle trajectory tracking and lateral control and reduce the chattering to a certain extent.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42415713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. To ensure the repeatability in a screwing task, the robot manipulators have to be calibrated regularly. If the allowable position error of the manipulator is increased, then the frequency of stopping a production line and calibrating the manipulators can be lower; therefore, the cost can be also decreased. This paper presents an innovative device for enlarging the allowable misalignment (DEAM) with five mechanisms, namely detecting, trigger, positioning, pin-and-stopper, and screwing mechanisms. By scanning around the target threaded hole, the screw can be precisely positioned at the location where the hole is detected by the probe. The motion and force analysis are carried out and verified through computer-aided simulation, and the sensitivity of the linkage tolerance is analyzed to ensure that the output position error of the mechanism does not affect the function of the device. Finally, the performance of the innovative device is verified by prototype testing, and the allowable misalignment is enlarged by about 6 times for an M6 screw.
{"title":"An innovative device for enlarging the allowable misalignment for screwing tasks","authors":"Hao Ku, Yu-Hsun Chen","doi":"10.5194/ms-13-701-2022","DOIUrl":"https://doi.org/10.5194/ms-13-701-2022","url":null,"abstract":"Abstract. To ensure the repeatability in a screwing task, the robot manipulators have to be calibrated regularly. If the allowable position error of the manipulator is increased, then the frequency of stopping a production line and calibrating the manipulators can be lower; therefore, the cost can be also decreased. This paper presents an innovative device for enlarging the allowable misalignment (DEAM) with five mechanisms, namely detecting, trigger, positioning, pin-and-stopper, and screwing mechanisms. By scanning around the target threaded hole, the screw can be precisely positioned at the location where the hole is detected by the probe. The motion and force analysis are carried out and verified through computer-aided simulation, and the sensitivity of the linkage tolerance is analyzed to ensure that the output position error of the mechanism does not affect the function of the device. Finally, the performance of the innovative device is verified by prototype testing, and the allowable misalignment is enlarged by about 6 times for an M6 screw.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44991258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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