Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787362
Adam Niewola, L. Podsędkowski, Jakub Niedzwiedzki
Mobile robots 6D outdoor localization algorithms using laser scanners in GPS-denied scenarios can rely on landmarks extraction or ICP-based scan matching. Both methods have significant disadvantages in rough terrain (lack of proper candidates for landmarks or problems with time consuming ICP-based scan matching), therefore, we proposed a new method based on robot's pose correction after every single laser scanner measurement, with the use of estimated distance between a scan point and the corresponding surfel on the reference 2.5D map known to mobile robot control system. The novelty of our method is that we do not have to make the point cloud registration into a common frame and we do not need extraction of landmarks from the point cloud as the landmark-based methods. Moreover, we do not require huge computational efforts in order to compare point clouds. We present the results of simulation tests using the data captured by FARO reference scanner and real terrain experiment with the use of our innovative laser scanner.
{"title":"Point-to-Surfel-Distance- (PSD-) Based 6D Localization Algorithm for Rough Terrain Exploration Using Laser Scanner in GPS-Denied Scenarios","authors":"Adam Niewola, L. Podsędkowski, Jakub Niedzwiedzki","doi":"10.1109/RoMoCo.2019.8787362","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787362","url":null,"abstract":"Mobile robots 6D outdoor localization algorithms using laser scanners in GPS-denied scenarios can rely on landmarks extraction or ICP-based scan matching. Both methods have significant disadvantages in rough terrain (lack of proper candidates for landmarks or problems with time consuming ICP-based scan matching), therefore, we proposed a new method based on robot's pose correction after every single laser scanner measurement, with the use of estimated distance between a scan point and the corresponding surfel on the reference 2.5D map known to mobile robot control system. The novelty of our method is that we do not have to make the point cloud registration into a common frame and we do not need extraction of landmarks from the point cloud as the landmark-based methods. Moreover, we do not require huge computational efforts in order to compare point clouds. We present the results of simulation tests using the data captured by FARO reference scanner and real terrain experiment with the use of our innovative laser scanner.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132861506","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787361
E. Macias-Garcia, Adan Cruz, J. Zamora, Eduardo Bayro
This paper introduces a novel drone navigation algorithm based on overlapped known regions (OKR). Each OKR has associated a neural network model, which takes as input an RGB image from a camera located at the top of the drone. This model generates two outputs: the distance to the center of the region, and the orientation of the vector that points to the center of the region in the horizontal plane. These regions are constrained to overlap the center of neighbor regions. After training, the drone is able to navigate continuously through several regions by switching the model parameters once the center of each region is reached. Additionally, in order to significantly reduce the number of parameters of each model an adaptive convolutional kernel (ACK) is used, which is able to redefine the convolutional kernel during the inference time according to the input image.
{"title":"Indoor Navigation Based on Model Switching in Overlapped Known Regions","authors":"E. Macias-Garcia, Adan Cruz, J. Zamora, Eduardo Bayro","doi":"10.1109/RoMoCo.2019.8787361","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787361","url":null,"abstract":"This paper introduces a novel drone navigation algorithm based on overlapped known regions (OKR). Each OKR has associated a neural network model, which takes as input an RGB image from a camera located at the top of the drone. This model generates two outputs: the distance to the center of the region, and the orientation of the vector that points to the center of the region in the horizontal plane. These regions are constrained to overlap the center of neighbor regions. After training, the drone is able to navigate continuously through several regions by switching the model parameters once the center of each region is reached. Additionally, in order to significantly reduce the number of parameters of each model an adaptive convolutional kernel (ACK) is used, which is able to redefine the convolutional kernel during the inference time according to the input image.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126491991","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787380
J. Piasek, Rafal Staszak, K. Piaskowski, D. Belter
In this paper, we propose the application of the Adam optimizer to extrinsic calibration of the multi -sensory system. Our robot is equipped with three RGB-D cameras. The first camera is attached to the wrist of the arm, the second camera is mounted in the robot's head, and the third camera is attached to the mobile base. Additionally, the pose of the wrist camera changes with respect to the robot frame and depends on the configuration of the robotic arm. The proposed method finds all relative transformations between cameras in a single optimization procedure. We compare the proposed application of Adam method with black-box evolutionary algorithm, Levenberg-Marquardt optimization, and graph-based optimization. We also evaluated three cost functions to verify the influence of various parameterization methods of the SO (3) rotation on the calibration results.
{"title":"Multi-sensor extrinsic calibration with the Adam optimizer","authors":"J. Piasek, Rafal Staszak, K. Piaskowski, D. Belter","doi":"10.1109/RoMoCo.2019.8787380","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787380","url":null,"abstract":"In this paper, we propose the application of the Adam optimizer to extrinsic calibration of the multi -sensory system. Our robot is equipped with three RGB-D cameras. The first camera is attached to the wrist of the arm, the second camera is mounted in the robot's head, and the third camera is attached to the mobile base. Additionally, the pose of the wrist camera changes with respect to the robot frame and depends on the configuration of the robotic arm. The proposed method finds all relative transformations between cameras in a single optimization procedure. We compare the proposed application of Adam method with black-box evolutionary algorithm, Levenberg-Marquardt optimization, and graph-based optimization. We also evaluated three cost functions to verify the influence of various parameterization methods of the SO (3) rotation on the calibration results.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116518386","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787352
S. Stępień, Paulina Superczyńska, O. Lindenau, Marcin Walesa
The paper presents modelling and control of a robotic arm. To solve the control problem, the state-dependent Riccati equation (SDRE) method is applied. As a new contribution, the paper deals with state-dependent parametrization as an effective modelling of robot manipulator and shows how to modify classical form of the SDRE method to reduce computational effort during feedback gain computation. Numerical example with 3 DOF manipulator compares described methods and confirms usefulness of the proposed technique.
{"title":"SDRE-Based Suboptimal Controller for Manipulator Control","authors":"S. Stępień, Paulina Superczyńska, O. Lindenau, Marcin Walesa","doi":"10.1109/RoMoCo.2019.8787352","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787352","url":null,"abstract":"The paper presents modelling and control of a robotic arm. To solve the control problem, the state-dependent Riccati equation (SDRE) method is applied. As a new contribution, the paper deals with state-dependent parametrization as an effective modelling of robot manipulator and shows how to modify classical form of the SDRE method to reduce computational effort during feedback gain computation. Numerical example with 3 DOF manipulator compares described methods and confirms usefulness of the proposed technique.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121874467","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787367
A. Ratajczak, J. Ratajczak
The paper presents a new algorithm for a trajectory planning problem. As a result, we obtain a control function which drives the system along the prescribed trajectory. This algorithm is embedded into an Endogenous Configuration Space Approach. The instantaneous map of the nonholonomic system allows us to construct a system of nonlinear functional equations which solution is a demanded control function. In order to solve the mentioned system of equations, the large scale root-finding algorithm is employed. The new trajectory reproduction algorithm is applied to solve the problem of an on-orbit servicing, namely a docking maneuver of a free-floating space manipulator with a tumbling target. The efficiency of the proposed approach is presented with a series of numerical experiments.
{"title":"Trajectory Reproduction Algorithm in Application to an On-Orbit Docking Maneuver with Tumbling Target","authors":"A. Ratajczak, J. Ratajczak","doi":"10.1109/RoMoCo.2019.8787367","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787367","url":null,"abstract":"The paper presents a new algorithm for a trajectory planning problem. As a result, we obtain a control function which drives the system along the prescribed trajectory. This algorithm is embedded into an Endogenous Configuration Space Approach. The instantaneous map of the nonholonomic system allows us to construct a system of nonlinear functional equations which solution is a demanded control function. In order to solve the mentioned system of equations, the large scale root-finding algorithm is employed. The new trajectory reproduction algorithm is applied to solve the problem of an on-orbit servicing, namely a docking maneuver of a free-floating space manipulator with a tumbling target. The efficiency of the proposed approach is presented with a series of numerical experiments.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115694273","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787376
Xueyou Zhang, Yongchun Fang, Wei Zhu, Xian Guo
In this paper, a quadruped salamander-like robot with the capability of traversing complex terrain is developed, which presents not only leg joints used in traditional legged robots, but also spine joints, so as to increases its flexibility. To coordinate spine and leg joints to balance the robot's center of gravity, a novel control method is proposed, which consists of an inverse kinematics-based control, a bio-inspired mechanism, and a coordination law. Specifically, the inverse kinematics is utilized to calculate the control for the legs, and biological inspiration is employed for the control of the spine, while the coordination between the legs and the spine is ensured by the utilization of the static stability principle. Some typical experiments, including walking straight, turning, and avoiding obstacles, are performed for the developed quadruped salamander-like robot, with the collected results convincingly demonstrating the effectiveness of the proposed control method and the developed robot.
{"title":"A Novel Locomotion Controller Based on Coordination Between Leg and Spine for a Quadruped Salamander-Like Robot","authors":"Xueyou Zhang, Yongchun Fang, Wei Zhu, Xian Guo","doi":"10.1109/RoMoCo.2019.8787376","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787376","url":null,"abstract":"In this paper, a quadruped salamander-like robot with the capability of traversing complex terrain is developed, which presents not only leg joints used in traditional legged robots, but also spine joints, so as to increases its flexibility. To coordinate spine and leg joints to balance the robot's center of gravity, a novel control method is proposed, which consists of an inverse kinematics-based control, a bio-inspired mechanism, and a coordination law. Specifically, the inverse kinematics is utilized to calculate the control for the legs, and biological inspiration is employed for the control of the spine, while the coordination between the legs and the spine is ensured by the utilization of the static stability principle. Some typical experiments, including walking straight, turning, and avoiding obstacles, are performed for the developed quadruped salamander-like robot, with the collected results convincingly demonstrating the effectiveness of the proposed control method and the developed robot.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123009747","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787364
S. LaValle
This paper addresses the sensing uncertainty associated with the many-to-one mapping from a physical state space onto a sensor observation space. By studying preimages of this mapping for each sensor, a notion of sensor dominance is introduced, which enables interchangeability of sensors and a clearer understanding of their tradeoffs. The notion of a sensor lattice is also introduced, in which all possible sensor models are arranged into a hierarchy that indicates their power and gives insights into the construction of filters over time and space. This provides a systematic way to compare and characterize information feedback in robotic systems, in terms of their level of ambiguity with regard to state estimation.
{"title":"Sensor Lattices: Structures for Comparing Information Feedback","authors":"S. LaValle","doi":"10.1109/RoMoCo.2019.8787364","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787364","url":null,"abstract":"This paper addresses the sensing uncertainty associated with the many-to-one mapping from a physical state space onto a sensor observation space. By studying preimages of this mapping for each sensor, a notion of sensor dominance is introduced, which enables interchangeability of sensors and a clearer understanding of their tradeoffs. The notion of a sensor lattice is also introduced, in which all possible sensor models are arranged into a hierarchy that indicates their power and gives insights into the construction of filters over time and space. This provides a systematic way to compare and characterize information feedback in robotic systems, in terms of their level of ambiguity with regard to state estimation.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123257387","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787354
Vibekananda Dutta, T. Zielińska
Predicting human activities is very important for human-aware robotic applications. The goal of this work is to forecast human activities that may require robot assistance. The proposed method applies the depth and visual information and the database. The activity is parsed into consecutive actions, some attributes of the actions are described by the probability functions. The method delivers the motion trajectories to nominally possible motion goals. The reasoning process is described by the graphs. The approach was evaluated using four data sets: CAD 60, CAD-120, WUT-17, and WUT-18. The solution efficiency comparing to the other state-of-art was investigated.
{"title":"Activities Prediction Using Structured Data Base","authors":"Vibekananda Dutta, T. Zielińska","doi":"10.1109/RoMoCo.2019.8787354","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787354","url":null,"abstract":"Predicting human activities is very important for human-aware robotic applications. The goal of this work is to forecast human activities that may require robot assistance. The proposed method applies the depth and visual information and the database. The activity is parsed into consecutive actions, some attributes of the actions are described by the probability functions. The method delivers the motion trajectories to nominally possible motion goals. The reasoning process is described by the graphs. The approach was evaluated using four data sets: CAD 60, CAD-120, WUT-17, and WUT-18. The solution efficiency comparing to the other state-of-art was investigated.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122645182","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787369
Adam Niewola, L. Podsędkowski
The perception systems in mobile robotics use large variety of sensors, however, the most reliable are vision systems and laser scanners. Among the laser scanners, one of the most popular are the lidars using multiple laser range finders (LRF). They emit a set of 16, 32, 64 or 128 laser beams with different elevation angle. The set of beams can rotate around the vertical axis providing different azimuths. This design causes a very good horizontal resolution but very poor vertical resolution. Moreover, while scanning from stationary position, these scanners get always the same points because each laser beam is emitted always in the same direction. Due to these facts, typical mobile robot tasks like robot localization, mapping, object recognition and collision avoidance, can easily fail. In this paper we present a design of a new 3D laser scanner using a single laser range finder and two optical elements rotating around the same axis. Our design ensures significantly bigger vertical resolution than currently available 3D scanners and provides possibility of increasing point cloud density. Although it uses only a single LRF and provides smaller measurement frequency, our research proved that it can be successfully used in mobile robot localization and mapping. We present the design in two versions - wide and narrow field-of-view (FOV).
{"title":"A novel 3D laser scanner design for variable density scanning","authors":"Adam Niewola, L. Podsędkowski","doi":"10.1109/RoMoCo.2019.8787369","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787369","url":null,"abstract":"The perception systems in mobile robotics use large variety of sensors, however, the most reliable are vision systems and laser scanners. Among the laser scanners, one of the most popular are the lidars using multiple laser range finders (LRF). They emit a set of 16, 32, 64 or 128 laser beams with different elevation angle. The set of beams can rotate around the vertical axis providing different azimuths. This design causes a very good horizontal resolution but very poor vertical resolution. Moreover, while scanning from stationary position, these scanners get always the same points because each laser beam is emitted always in the same direction. Due to these facts, typical mobile robot tasks like robot localization, mapping, object recognition and collision avoidance, can easily fail. In this paper we present a design of a new 3D laser scanner using a single laser range finder and two optical elements rotating around the same axis. Our design ensures significantly bigger vertical resolution than currently available 3D scanners and provides possibility of increasing point cloud density. Although it uses only a single LRF and provides smaller measurement frequency, our research proved that it can be successfully used in mobile robot localization and mapping. We present the design in two versions - wide and narrow field-of-view (FOV).","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122747959","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}
Pub Date : 2019-07-01DOI: 10.1109/RoMoCo.2019.8787359
N. Sato, Makoto Kitani, Y. Morita
Various robots that operate in dangerous environments have been developed. A robot falling down is a critical incident, and many studies have been conducted to avoid the rollover situation. However, in a disaster site, the robot may rollover even if previous control methods are implemented. Therefore, it is necessary to develop a control method to recover from the rollover situation. The objective of this study is to realize autonomous control for the rollover recovery of a rescue robot. Initially, subcrawlers are controlled to reduce the normalized energy stability margin. Subsequently, if the robot cannot recover by using the subcrawlers, a manipulator is used to push the ground, rotate the robot, and then recover from the rollover situation. The experiment was performed to verify the effectiveness of the proposed control method using the Gazebo simulator where a dynamics engine, named the Open Dynamics Engine, was installed.
{"title":"Control Method for Rollover Recovery of Rescue Robot Considering Normalized Energy Stability Margin and Manipulating Force","authors":"N. Sato, Makoto Kitani, Y. Morita","doi":"10.1109/RoMoCo.2019.8787359","DOIUrl":"https://doi.org/10.1109/RoMoCo.2019.8787359","url":null,"abstract":"Various robots that operate in dangerous environments have been developed. A robot falling down is a critical incident, and many studies have been conducted to avoid the rollover situation. However, in a disaster site, the robot may rollover even if previous control methods are implemented. Therefore, it is necessary to develop a control method to recover from the rollover situation. The objective of this study is to realize autonomous control for the rollover recovery of a rescue robot. Initially, subcrawlers are controlled to reduce the normalized energy stability margin. Subsequently, if the robot cannot recover by using the subcrawlers, a manipulator is used to push the ground, rotate the robot, and then recover from the rollover situation. The experiment was performed to verify the effectiveness of the proposed control method using the Gazebo simulator where a dynamics engine, named the Open Dynamics Engine, was installed.","PeriodicalId":415070,"journal":{"name":"2019 12th International Workshop on Robot Motion and Control (RoMoCo)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134092447","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：