The current literature lacks uniform calculation methods for following trajectory control for autonomous vehicles,including the calculation of errors,determination of tracking points,and design of feedforward controll...The current literature lacks uniform calculation methods for following trajectory control for autonomous vehicles,including the calculation of errors,determination of tracking points,and design of feedforward controllers.Hence,a complete calculation method is proposed to address this gap.First,a control equation in the form of an error is obtained according to the dynamic equation of the vehicle coordinate system and the trajectory following model.Secondly,the deviation of the vehicle state is obtained according to the current vehicle s state and the following control model.Finally,a linear quadratic regulator(LQR)controller with feedforward control is designed according to the characteristics of the dynamic equation.With the proposed LQR,the simulation of computational time,anti-interference,and reliability analysis of the trajectory following control is performed by programming using MATLAB.The simulation outcomes are then compared with the experimental results from the literature.The comparison indicates that the proposed complete calculation method is effective,reliable,and capable of achieving real-time and anti-interference following control performance.The simulation results with or without feedforward control show that the steady-state error is eliminated and that good control performance is obtained by introducing feedforward control.展开更多
For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting ...For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting in the inability to balance the system robustness and dynamic performance.A PMSM optimal control strategy combining linear active disturbance rejection control(LADRC)and two-vector MPCC(TV-MPCC)is proposed.Firstly,a mathematical model of a PMSM is presented,and the PMSM TV-MPCC model is developed in the synchronous rotation coordinate system.Secondly,a first-order LADRC controller composed of a linear extended state observer and linear state error feedback is designed to reduce the complexity of parameter tuning while linearly simplifying the traditional active disturbance rejection control(ADRC)structure.Finally,the conventional PI speed regulator in the motor speed control system is replaced by the designed LADRC controller.The simulation results show that the speed control system using LADRC can effectively deal with the changes in motor parameters and has better robustness and dynamic performance than PI control and similar methods.The system has a fast motor speed response,small overshoot,strong anti-interference,and no steady-state error,and the total harmonic distortion is reduced.展开更多
The saturation problem is the one of the most common handicaps for applying to real applications, especially the actuator saturation. This paper focuses on the robustness of the sliding mode control (SMC) which inco...The saturation problem is the one of the most common handicaps for applying to real applications, especially the actuator saturation. This paper focuses on the robustness of the sliding mode control (SMC) which incorporates a saturation constraint technique compared to classical linear quadratic regulator (LQR) with saturation. In the first step, the authors present a design methodology of SMC of a class of linear saturated systems. The authors present the structure of the saturation, after that the synthesis of the sliding surface is formulate as a problem of root clustering, which leads to the development of a continuous and non-linear control law that ensures the reaching condition of the sliding mode. The second step is devoted to present briefly the LQR controller technique. Finally, to validate results, the authors demonstrate an example of a quarter of vehicle system.展开更多
Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be cha...Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.展开更多
A communication system based on an ultraviolet(UV) laser at 266 nm is presented to improve the communication distance. The pulse frequency-shift keying(FSK) modulation scheme is studied and improved in order to reduce...A communication system based on an ultraviolet(UV) laser at 266 nm is presented to improve the communication distance. The pulse frequency-shift keying(FSK) modulation scheme is studied and improved in order to reduce the bit error rate(BER), and is put into practice on a field programmable gate array(FPGA). The mathematical models of the modulation and demodulation are established. A test platform is set up to measure the energy density and pulse response under different distances and receiver elevation angles. It is shown that the omnibearing communication can be realized, and the bit rate is limited to 12.5 Mbit/s. The BER is estimated to be less than 10-7 at distance of 300 m in line-of-sight(LOS) communication model and to be less than 10-6 at distance of 80 m in non-line-of-sight(NLOS) communication model.展开更多
基金The National Key Research and Development Program of China(No.2019YFB2006404)Guangxi Science and Technology Major Project(No.GUIKE AA18242036,No.GUIKE AA18242037).
文摘The current literature lacks uniform calculation methods for following trajectory control for autonomous vehicles,including the calculation of errors,determination of tracking points,and design of feedforward controllers.Hence,a complete calculation method is proposed to address this gap.First,a control equation in the form of an error is obtained according to the dynamic equation of the vehicle coordinate system and the trajectory following model.Secondly,the deviation of the vehicle state is obtained according to the current vehicle s state and the following control model.Finally,a linear quadratic regulator(LQR)controller with feedforward control is designed according to the characteristics of the dynamic equation.With the proposed LQR,the simulation of computational time,anti-interference,and reliability analysis of the trajectory following control is performed by programming using MATLAB.The simulation outcomes are then compared with the experimental results from the literature.The comparison indicates that the proposed complete calculation method is effective,reliable,and capable of achieving real-time and anti-interference following control performance.The simulation results with or without feedforward control show that the steady-state error is eliminated and that good control performance is obtained by introducing feedforward control.
文摘For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting in the inability to balance the system robustness and dynamic performance.A PMSM optimal control strategy combining linear active disturbance rejection control(LADRC)and two-vector MPCC(TV-MPCC)is proposed.Firstly,a mathematical model of a PMSM is presented,and the PMSM TV-MPCC model is developed in the synchronous rotation coordinate system.Secondly,a first-order LADRC controller composed of a linear extended state observer and linear state error feedback is designed to reduce the complexity of parameter tuning while linearly simplifying the traditional active disturbance rejection control(ADRC)structure.Finally,the conventional PI speed regulator in the motor speed control system is replaced by the designed LADRC controller.The simulation results show that the speed control system using LADRC can effectively deal with the changes in motor parameters and has better robustness and dynamic performance than PI control and similar methods.The system has a fast motor speed response,small overshoot,strong anti-interference,and no steady-state error,and the total harmonic distortion is reduced.
文摘The saturation problem is the one of the most common handicaps for applying to real applications, especially the actuator saturation. This paper focuses on the robustness of the sliding mode control (SMC) which incorporates a saturation constraint technique compared to classical linear quadratic regulator (LQR) with saturation. In the first step, the authors present a design methodology of SMC of a class of linear saturated systems. The authors present the structure of the saturation, after that the synthesis of the sliding surface is formulate as a problem of root clustering, which leads to the development of a continuous and non-linear control law that ensures the reaching condition of the sliding mode. The second step is devoted to present briefly the LQR controller technique. Finally, to validate results, the authors demonstrate an example of a quarter of vehicle system.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0700201,2017YFA0700203 and 2016YFC0800401)National Natural Science Foundation of China(61890544,61522106,61631007,61571117,61731010,61735010,61722106,61701107,and 61701108)+3 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX19_0081)Scientific Research Foundation of Graduate School of Southeast University(YBPY1938)Foundation of National Excellent Doctoral Dissertation of China(201444)the 111 Project(111-2-05).
文摘Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.
基金supported by the National Natural Science Foundation of China(No.11075226)the Natural Science Foundation of Chongqing(No.cstc2014jcyjA 90010)
文摘A communication system based on an ultraviolet(UV) laser at 266 nm is presented to improve the communication distance. The pulse frequency-shift keying(FSK) modulation scheme is studied and improved in order to reduce the bit error rate(BER), and is put into practice on a field programmable gate array(FPGA). The mathematical models of the modulation and demodulation are established. A test platform is set up to measure the energy density and pulse response under different distances and receiver elevation angles. It is shown that the omnibearing communication can be realized, and the bit rate is limited to 12.5 Mbit/s. The BER is estimated to be less than 10-7 at distance of 300 m in line-of-sight(LOS) communication model and to be less than 10-6 at distance of 80 m in non-line-of-sight(NLOS) communication model.