The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Hui Zhang - One of the best experts on this subject based on the ideXlab platform.
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sideslip angle estimation of an electric ground vehicle via finite frequency mathcal h _ infty approach
IEEE Transactions on Transportation Electrification, 2016Co-Authors: Hui Zhang, Guoguang Zhang, Junmin WangAbstract:The lateral stability is critically important especially when the vehicle is steered at a high longitudinal speed. Loss of lateral stability would lead to severe accidents. Therefore, the study of lateral stability has been a hot topic for decades. In order to monitor the lateral stability or improve the stability by using the feedback control, the sideslip angle is an important index. However, the sideslip angle is not measurable by using an affordable Physical Sensor. An alternative approach is to estimate the sideslip angle with the measurements of relatively cheap Sensors. In this paper, we investigate the problem of sideslip angle observer design for an electric ground vehicle (EGV). The EGV is equipped with an advanced navigation system. The lateral velocity, the longitudinal velocity, and the yaw rate are available. Thus, the sideslip angle which is defined as the ratio of lateral velocity and longitudinal velocity is also available. Meanwhile, the hand-wheel steering angle is also measurable in this application. The main work is to estimate the sideslip angle with the measurements of yaw rate based on the vehicle lateral dynamics. The dynamic model is first established and the parameters are identified with experimental data. Since the dynamic model is nonlinear, in order to facilitate the system analysis and observer design, the nonlinear model is transformed to a linear-parameter-varying (LPV) system. An observer is proposed based on the LPV form. By defining the estimation error, a compact system which contains the estimation error and the original dynamics is obtained. Considering the frequency of the front-wheel steering angle, the finite-frequency $\mathcal {H}_{\infty}$ performance of the compact system is exploited. An optimal observer design method is then developed. For the EGV, the observer is designed according to the developed method. The performance of the designed observer is illustrated with experimental test data.
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robust energy to peak sideslip angle estimation with applications to ground vehicles
Mechatronics, 2015Co-Authors: Junmin Wang, Hui Zhang, Xiaoyu Huang, Hamid Reza KarimiAbstract:Abstract In this paper, the observer design problem for the sideslip angle of ground vehicles is investigated. The sideslip angle is an important signal for the vehicle lateral stability, which is not measurable by using an affordable Physical Sensor. Therefore, we aim to estimate the sideslip angle with the yaw rate measurements by employing the vehicle dynamics. The nonlinear lateral dynamics is modeled firstly. As the tyre model is nonlinear and the road adhesive coefficient is subject to a large variation, the nonlinear lateral dynamics is transformed into an uncertain model. Considering the variation of longitudinal velocity, an uncertain linear-parameter-varying (LPV) system is obtained. Based on the LPV model, a gain-scheduling observer is proposed and the observer gain can be determined with off-line computation and on-line computation. The off-line computation includes the calculation of a set of linear matrix inequalities and the on-line computation contains several algebraic operations. The proposed design methodology is applied to a four-wheel-independent-drive electric vehicle in simulation. It infers from different maneuvers that the designed observer has a good performance on estimating the sideslip angle.
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nonlinear observer design of diesel engine selective catalytic reduction systems with hbox no _ x Sensor measurements
IEEE-ASME Transactions on Mechatronics, 2015Co-Authors: Hui Zhang, Junmin Wang, Yueyun WangAbstract:In this paper, we investigate the observer design problem of diesel engine selective catalytic reduction (SCR) systems. Considering the main chemical reactions, the SCR systems are modeled by assuming that the states are homogenous inside and SCR cells as continuous stirred tank reactors. The obtained system model is nonlinear and the states are coupled. Since the ammonia coverage ratio is not measurable by a Physical Sensor and the ammonia Sensor is relatively costly, $\hbox{NO}_{x}$ Sensors are used to estimate the system states. The observability of the system is analyzed under the framework of the linear parameter-varying (LPV) system via transforming the nonlinear SCR system into a quasi-LPV form. A nonlinear observer is proposed and the method of tuning the observer gains is developed. The stability of the estimation error system is guaranteed with the designed observer gains. Finally, an experimental test with various operating points is conducted to show the effectiveness of the designed observer. It infers from the results that the designed observer has a good performance and the states are estimated well.
Nae Eung Lee - One of the best experts on this subject based on the ideXlab platform.
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Flexible and Stretchable Physical Sensor Integrated Platforms for Wearable Human-Activity Monitoringand Personal Healthcare
Advanced Materials, 2016Co-Authors: Tran Quang Trung, Nae Eung LeeAbstract:Flexible and stretchable Physical Sensors that can measure and quantify electrical signals generated by human activities are attracting a great deal of attention as they have unique characteristics, such as ultrathinness, low modulus, light weight, high flexibility, and stretchability. These flexible and stretchable Physical Sensors conformally attached on the surface of organs or skin can provide a new opportunity for human-activity monitoring and personal healthcare. Consequently, in recent years there has been considerable research effort devoted to the development of flexible and stretchable Physical Sensors to fulfill the requirements of future technology, and much progress has been achieved. Here, the most recent developments of flexible and stretchable Physical Sensors are described, including temperature, pressure, and strain Sensors, and flexible and stretchable Sensor-integrated platforms. The latest successful examples of flexible and stretchable Physical Sensors for the detection of temperature, pressure, and strain, as well as their novel structures, technological innovations, and challenges, are reviewed first. In the next section, recent progress regarding Sensor-integrated wearable platforms is overviewed in detail. Some of the latest achievements regarding self-powered Sensor-integrated wearable platform technologies are also reviewed. Further research direction and challenges are also proposed to develop a fully Sensor-integrated wearable platform for monitoring human activity and personal healthcare in the near future.
Daniela Rus - One of the best experts on this subject based on the ideXlab platform.
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deploying Sensor networks with guaranteed capacity and fault tolerance
Mobile Ad Hoc Networking and Computing, 2005Co-Authors: Jonathan Bredin, Erik D Demaine, Mohammadtaghi Hajiaghayi, Daniela RusAbstract:We consider the problem of deploying or repairing a Sensor network to guarantee a specified level of multi-path connectivity (k-connectivity) between all nodes. Such a guarantee simultaneously provides fault tolerance against node failures and high capacity through multi-path routing. We design and analyze the first algorithms that place an almost-minimum number of additional Sensors to augment an existing network into a k-connected network, for any desired parameter k. Our algorithms have provable guarantees on the quality of the solution. Specifically, we prove that the number of additional Sensors is within a constant factor of the absolute minimum, for any fixed k. We have implemented greedy and distributed versions of this algorithm, and demonstrate in simulation that they produce high-quality placements for the additional Sensors. We are also in the process of using our algorithms to deploy nodes in a Physical Sensor network using a mobile robot.
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robust distributed network localization with noisy range measurements
International Conference on Embedded Networked Sensor Systems, 2004Co-Authors: David Moore, Daniela Rus, John J Leonard, Seth TellerAbstract:This paper describes a distributed, linear-time algorithm for localizing Sensor network nodes in the presence of range measurement noise and demonstrates the algorithm on a Physical network. We introduce the probabilistic notion of robust quadrilaterals as a way to avoid flip ambiguities that otherwise corrupt localization computations. We formulate the localization problem as a two-dimensional graph realization problem: given a planar graph with approximately known edge lengths, recover the Euclidean position of each vertex up to a global rotation and translation. This formulation is applicable to the localization of Sensor networks in which each node can estimate the distance to each of its neighbors, but no absolute position reference such as GPS or fixed anchor nodes is available. We implemented the algorithm on a Physical Sensor network and empirically assessed its accuracy and performance. Also, in simulation, we demonstrate that the algorithm scales to large networks and handles real-world deployment geometries. Finally, we show how the algorithm supports localization of mobile nodes.
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robust distributed network localization with noisy range measurements
International Conference on Embedded Networked Sensor Systems, 2004Co-Authors: David Moore, Daniela Rus, John J Leonard, Seth TellerAbstract:This paper describes a distributed, linear-time algorithm for localizing Sensor network nodes in the presence of range measurement noise and demonstrates the algorithm on a Physical network. We introduce the probabilistic notion of robust quadrilaterals as a way to avoid flip ambiguities that otherwise corrupt localization computations. We formulate the localization problem as a two-dimensional graph realization problem: given a planar graph with approximately known edge lengths, recover the Euclidean position of each vertex up to a global rotation and translation. This formulation is applicable to the localization of Sensor networks in which each node can estimate the distance to each of its neighbors, but no absolute position reference such as GPS or fixed anchor nodes is available. We implemented the algorithm on a Physical Sensor network and empirically assessed its accuracy and performance. Also, in simulation, we demonstrate that the algorithm scales to large networks and handles real-world deployment geometries. Finally, we show how the algorithm supports localization of mobile nodes.
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distributed algorithms for guiding navigation across a Sensor network
ACM IEEE International Conference on Mobile Computing and Networking, 2003Co-Authors: Michael De Rosa, Daniela RusAbstract:We develop distributed algorithms for self-organizing Sensor networks that respond to directing a target through a region. The Sensor network models the danger levels sensed across its area and has the ability to adapt to changes. It represents the dangerous areas as obstacles. A protocol that combines the artificial potential field of the Sensors with the goal location for the moving object guides the object incrementally across the network to the goal, while maintaining the safest distance to the danger areas. We give the analysis to the protocol and report on hardware experiments using a Physical Sensor network consisting of Mote Sensors.
Junmin Wang - One of the best experts on this subject based on the ideXlab platform.
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sideslip angle estimation of an electric ground vehicle via finite frequency mathcal h _ infty approach
IEEE Transactions on Transportation Electrification, 2016Co-Authors: Hui Zhang, Guoguang Zhang, Junmin WangAbstract:The lateral stability is critically important especially when the vehicle is steered at a high longitudinal speed. Loss of lateral stability would lead to severe accidents. Therefore, the study of lateral stability has been a hot topic for decades. In order to monitor the lateral stability or improve the stability by using the feedback control, the sideslip angle is an important index. However, the sideslip angle is not measurable by using an affordable Physical Sensor. An alternative approach is to estimate the sideslip angle with the measurements of relatively cheap Sensors. In this paper, we investigate the problem of sideslip angle observer design for an electric ground vehicle (EGV). The EGV is equipped with an advanced navigation system. The lateral velocity, the longitudinal velocity, and the yaw rate are available. Thus, the sideslip angle which is defined as the ratio of lateral velocity and longitudinal velocity is also available. Meanwhile, the hand-wheel steering angle is also measurable in this application. The main work is to estimate the sideslip angle with the measurements of yaw rate based on the vehicle lateral dynamics. The dynamic model is first established and the parameters are identified with experimental data. Since the dynamic model is nonlinear, in order to facilitate the system analysis and observer design, the nonlinear model is transformed to a linear-parameter-varying (LPV) system. An observer is proposed based on the LPV form. By defining the estimation error, a compact system which contains the estimation error and the original dynamics is obtained. Considering the frequency of the front-wheel steering angle, the finite-frequency $\mathcal {H}_{\infty}$ performance of the compact system is exploited. An optimal observer design method is then developed. For the EGV, the observer is designed according to the developed method. The performance of the designed observer is illustrated with experimental test data.
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robust energy to peak sideslip angle estimation with applications to ground vehicles
Mechatronics, 2015Co-Authors: Junmin Wang, Hui Zhang, Xiaoyu Huang, Hamid Reza KarimiAbstract:Abstract In this paper, the observer design problem for the sideslip angle of ground vehicles is investigated. The sideslip angle is an important signal for the vehicle lateral stability, which is not measurable by using an affordable Physical Sensor. Therefore, we aim to estimate the sideslip angle with the yaw rate measurements by employing the vehicle dynamics. The nonlinear lateral dynamics is modeled firstly. As the tyre model is nonlinear and the road adhesive coefficient is subject to a large variation, the nonlinear lateral dynamics is transformed into an uncertain model. Considering the variation of longitudinal velocity, an uncertain linear-parameter-varying (LPV) system is obtained. Based on the LPV model, a gain-scheduling observer is proposed and the observer gain can be determined with off-line computation and on-line computation. The off-line computation includes the calculation of a set of linear matrix inequalities and the on-line computation contains several algebraic operations. The proposed design methodology is applied to a four-wheel-independent-drive electric vehicle in simulation. It infers from different maneuvers that the designed observer has a good performance on estimating the sideslip angle.
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nonlinear observer design of diesel engine selective catalytic reduction systems with hbox no _ x Sensor measurements
IEEE-ASME Transactions on Mechatronics, 2015Co-Authors: Hui Zhang, Junmin Wang, Yueyun WangAbstract:In this paper, we investigate the observer design problem of diesel engine selective catalytic reduction (SCR) systems. Considering the main chemical reactions, the SCR systems are modeled by assuming that the states are homogenous inside and SCR cells as continuous stirred tank reactors. The obtained system model is nonlinear and the states are coupled. Since the ammonia coverage ratio is not measurable by a Physical Sensor and the ammonia Sensor is relatively costly, $\hbox{NO}_{x}$ Sensors are used to estimate the system states. The observability of the system is analyzed under the framework of the linear parameter-varying (LPV) system via transforming the nonlinear SCR system into a quasi-LPV form. A nonlinear observer is proposed and the method of tuning the observer gains is developed. The stability of the estimation error system is guaranteed with the designed observer gains. Finally, an experimental test with various operating points is conducted to show the effectiveness of the designed observer. It infers from the results that the designed observer has a good performance and the states are estimated well.
Tran Quang Trung - One of the best experts on this subject based on the ideXlab platform.
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Flexible and Stretchable Physical Sensor Integrated Platforms for Wearable Human-Activity Monitoringand Personal Healthcare
Advanced Materials, 2016Co-Authors: Tran Quang Trung, Nae Eung LeeAbstract:Flexible and stretchable Physical Sensors that can measure and quantify electrical signals generated by human activities are attracting a great deal of attention as they have unique characteristics, such as ultrathinness, low modulus, light weight, high flexibility, and stretchability. These flexible and stretchable Physical Sensors conformally attached on the surface of organs or skin can provide a new opportunity for human-activity monitoring and personal healthcare. Consequently, in recent years there has been considerable research effort devoted to the development of flexible and stretchable Physical Sensors to fulfill the requirements of future technology, and much progress has been achieved. Here, the most recent developments of flexible and stretchable Physical Sensors are described, including temperature, pressure, and strain Sensors, and flexible and stretchable Sensor-integrated platforms. The latest successful examples of flexible and stretchable Physical Sensors for the detection of temperature, pressure, and strain, as well as their novel structures, technological innovations, and challenges, are reviewed first. In the next section, recent progress regarding Sensor-integrated wearable platforms is overviewed in detail. Some of the latest achievements regarding self-powered Sensor-integrated wearable platform technologies are also reviewed. Further research direction and challenges are also proposed to develop a fully Sensor-integrated wearable platform for monitoring human activity and personal healthcare in the near future.