传统的跟踪雷达中使用多普勒滤波器组结构的距离、速度联合估计器是理论上的最大似然估计器，这种估计器结构复杂开销大，在多目标环境下对小目标检测有损失．在对具有比较宽的多普勒响应范围的非线性调频（NonLinear Frequency Modulat...传统的跟踪雷达中使用多普勒滤波器组结构的距离、速度联合估计器是理论上的最大似然估计器，这种估计器结构复杂开销大，在多目标环境下对小目标检测有损失．在对具有比较宽的多普勒响应范围的非线性调频（NonLinear Frequency Modulation,NLFM）波形优化设计的基础上，文章提出了一种双通道非线性调频脉压结构的参数估计器，并分析了其理论性能，给出了相应的仿真结果．展开更多
In order to save energy consumption of two-way amplifier forward(AF) relaying with channel estimation error, an energy efficiency enhancement scheme is proposed in this work. Firstly, through the analysis of two-way A...In order to save energy consumption of two-way amplifier forward(AF) relaying with channel estimation error, an energy efficiency enhancement scheme is proposed in this work. Firstly, through the analysis of two-way AF relaying mode with channel estimation error, the resultant instantaneous SNRs at end nodes is obtained. Then, by using a high SNR approximation, outage possibility is acquired and its simple closed-form expression is represented. Specially, for using the energy resource more efficiently, a low-complexity power allocation and transmission mode selection policy is proposed to enhance the energy efficiency of two-way AF relay system. Finally, relay priority region is identified in which cooperative diversity energy gain can be achieved. The computer simulations are presented to verify our analytical results, indicating that the proposed policy outperforms direct transmission by an energy gain of 3 dB at the relative channel estimation error less than 0.001. The results also show that the two-way AF relaying transmission loses the two-way AF relaying transmission loses its superiority to direct transmission in terms of energy efficiency when channel estimation error reaches 0.03.展开更多
We are developing a nursing-care robot for physical care tasks. The concept of this robot is to promote the cared persons by the robot to activate their own motion ability as long as possible. This may lead to the imp...We are developing a nursing-care robot for physical care tasks. The concept of this robot is to promote the cared persons by the robot to activate their own motion ability as long as possible. This may lead to the improvement of the cared person＇s movement volition and movement abilities. In order to realize safe and human friendly robot care tasks, full body manipulation is an important technology, for which it is necessary to estimate the subject＇s center of gravity from the contact positions and forces with the robot＇s two arms. In this paper, we estimate the center of gravity of object based on the contact point and the contact force estimated by force sensor on both robot arms. The position of gravity center is important to realize care tasks stably. We performed experiments and simulations for the single point contact and dual points contact cases using a cylindrical object. As a result, it is found that although some errors were recognized in the experiments compared with the simulations, the relations between the contact positions and such errors were observed. Such experimental error mainly comes from the difference of shape between the real robot and the model of the robot in simulation.展开更多
文摘传统的跟踪雷达中使用多普勒滤波器组结构的距离、速度联合估计器是理论上的最大似然估计器，这种估计器结构复杂开销大，在多目标环境下对小目标检测有损失．在对具有比较宽的多普勒响应范围的非线性调频（NonLinear Frequency Modulation,NLFM）波形优化设计的基础上，文章提出了一种双通道非线性调频脉压结构的参数估计器，并分析了其理论性能，给出了相应的仿真结果．
基金Project(IRT0852) supported by the Program for Changjiang Scholars and Innovative Research Team in University,ChinaProject(2012CB316100) supported by the National Basic Research Program of China+2 种基金Projects(61101144,61101145) supported by the National Natural Science Foundation of ChinaProject(B08038) supported by the "111" Project,ChinaProject(K50510010017) supported by the Fundamental Research Funds for the Central Universities,China
文摘In order to save energy consumption of two-way amplifier forward(AF) relaying with channel estimation error, an energy efficiency enhancement scheme is proposed in this work. Firstly, through the analysis of two-way AF relaying mode with channel estimation error, the resultant instantaneous SNRs at end nodes is obtained. Then, by using a high SNR approximation, outage possibility is acquired and its simple closed-form expression is represented. Specially, for using the energy resource more efficiently, a low-complexity power allocation and transmission mode selection policy is proposed to enhance the energy efficiency of two-way AF relay system. Finally, relay priority region is identified in which cooperative diversity energy gain can be achieved. The computer simulations are presented to verify our analytical results, indicating that the proposed policy outperforms direct transmission by an energy gain of 3 dB at the relative channel estimation error less than 0.001. The results also show that the two-way AF relaying transmission loses the two-way AF relaying transmission loses its superiority to direct transmission in terms of energy efficiency when channel estimation error reaches 0.03.
文摘We are developing a nursing-care robot for physical care tasks. The concept of this robot is to promote the cared persons by the robot to activate their own motion ability as long as possible. This may lead to the improvement of the cared person＇s movement volition and movement abilities. In order to realize safe and human friendly robot care tasks, full body manipulation is an important technology, for which it is necessary to estimate the subject＇s center of gravity from the contact positions and forces with the robot＇s two arms. In this paper, we estimate the center of gravity of object based on the contact point and the contact force estimated by force sensor on both robot arms. The position of gravity center is important to realize care tasks stably. We performed experiments and simulations for the single point contact and dual points contact cases using a cylindrical object. As a result, it is found that although some errors were recognized in the experiments compared with the simulations, the relations between the contact positions and such errors were observed. Such experimental error mainly comes from the difference of shape between the real robot and the model of the robot in simulation.
