Owning to the unique property of generating pure bending deformation, flexoelectric curvature actuators hold promise for various future applications, especially in the micro and nano scales. This paper proposes three ...Owning to the unique property of generating pure bending deformation, flexoelectric curvature actuators hold promise for various future applications, especially in the micro and nano scales. This paper proposes three models to predict the deformation of one-dimensional isotropic beams under the excitation of flexoelectric curvature actuators, including the pin-moment model, the pin-force-moment model and Euler-Bernoulli model. The pin-moment model represents the simplest model by only considering the moments interaction between the actuators and the beam at both ends, while the pin-force-moment model incorporate both the force and moment interactions. Comparison between the results of these two models with the Euler-Bernoulli model results indicates that the pin-moment model overestimates the curvature of the beam under a small thickness ratio of the beam and actuator, whereas a good agreement is reached between the pin-force-moment model results with that obtained by the Euler-Bernoulli-model. The accuracy of the pin-force-moment model and the Euler-Bernoulli model was further verified by a finite-element analysis. Therefore the pin-force-moment model could provide a simple and accurate method to characterise the performance of flexoelectric curvature actuators, enlightening the implementation of them for numerous future applications.展开更多
Future worksites will be occupied by different level of automation work machines. How these machines are working individually and how a fleet of these machines cooperates will be in focus of research and development w...Future worksites will be occupied by different level of automation work machines. How these machines are working individually and how a fleet of these machines cooperates will be in focus of research and development work in the future. In this paper the studied off-road vehicle is a wheel loader. It can be controlled manually, remotely or autonomously. The control strategy of autonomous wheel loader is consisting of, e.g., static and dynamic mapping, path planning, obstacle observation and avoidance. In the autonomous machines and also in machines where operator assistance system is active the situational awareness is the key research field. Power management in hydraulic work machines are still active fields of research. Multiple architectures and configurations have been suggested concerning this area. In addition, implemented solutions that consider an entire machine are rarely presented. This paper introduces the research work of the control systems which are minimising the fuel consumption.展开更多
A Kalman filter which estimates unsteady laminar flow in a pipe is implemented on a real-time computing system. The plant model is the optimised finite element model of pipeline dynamics considering unsteady laminar f...A Kalman filter which estimates unsteady laminar flow in a pipe is implemented on a real-time computing system. The plant model is the optimised finite element model of pipeline dynamics considering unsteady laminar friction. A steady-state Kalman filter is built based on the model of pipeline dynamics. Pressure signals at both ends of a target section of a pipe are input to the model of pipeline dynamics, and as an output of the model an estimated pressure signal at a mid-point of the pipe is obtained. Difference between measured and estimated pressure signals at the mid-point is fed back to the model of pipeline dynamics to modify state variables of the model. According to the Kalman filter principle, the state variables of the model are adjusted so that they converge to real values. It is demonstrated that real-time implementation of the Kalman filter is possible with the sampling time of 0.1 ms.展开更多
文摘Owning to the unique property of generating pure bending deformation, flexoelectric curvature actuators hold promise for various future applications, especially in the micro and nano scales. This paper proposes three models to predict the deformation of one-dimensional isotropic beams under the excitation of flexoelectric curvature actuators, including the pin-moment model, the pin-force-moment model and Euler-Bernoulli model. The pin-moment model represents the simplest model by only considering the moments interaction between the actuators and the beam at both ends, while the pin-force-moment model incorporate both the force and moment interactions. Comparison between the results of these two models with the Euler-Bernoulli model results indicates that the pin-moment model overestimates the curvature of the beam under a small thickness ratio of the beam and actuator, whereas a good agreement is reached between the pin-force-moment model results with that obtained by the Euler-Bernoulli-model. The accuracy of the pin-force-moment model and the Euler-Bernoulli model was further verified by a finite-element analysis. Therefore the pin-force-moment model could provide a simple and accurate method to characterise the performance of flexoelectric curvature actuators, enlightening the implementation of them for numerous future applications.
文摘Future worksites will be occupied by different level of automation work machines. How these machines are working individually and how a fleet of these machines cooperates will be in focus of research and development work in the future. In this paper the studied off-road vehicle is a wheel loader. It can be controlled manually, remotely or autonomously. The control strategy of autonomous wheel loader is consisting of, e.g., static and dynamic mapping, path planning, obstacle observation and avoidance. In the autonomous machines and also in machines where operator assistance system is active the situational awareness is the key research field. Power management in hydraulic work machines are still active fields of research. Multiple architectures and configurations have been suggested concerning this area. In addition, implemented solutions that consider an entire machine are rarely presented. This paper introduces the research work of the control systems which are minimising the fuel consumption.
文摘A Kalman filter which estimates unsteady laminar flow in a pipe is implemented on a real-time computing system. The plant model is the optimised finite element model of pipeline dynamics considering unsteady laminar friction. A steady-state Kalman filter is built based on the model of pipeline dynamics. Pressure signals at both ends of a target section of a pipe are input to the model of pipeline dynamics, and as an output of the model an estimated pressure signal at a mid-point of the pipe is obtained. Difference between measured and estimated pressure signals at the mid-point is fed back to the model of pipeline dynamics to modify state variables of the model. According to the Kalman filter principle, the state variables of the model are adjusted so that they converge to real values. It is demonstrated that real-time implementation of the Kalman filter is possible with the sampling time of 0.1 ms.