In this paper a new spherical actuator is designed and its advantages are compared to an existing spherical actuator, which function is limited by several design bottlenecks. First the output torque is too small. Seco...In this paper a new spherical actuator is designed and its advantages are compared to an existing spherical actuator, which function is limited by several design bottlenecks. First the output torque is too small. Second, the attitude is difficult to be accurately detected. The new three-dimen- sional magnetic pole array can solve these major problems. The new actuator features an outer rotor with multiple permanent magnet （PM） poles. Using an analytical solution and the finite element so- lution simulation, the feasibility of the approach is verified. A prototype was developed, tested, and experiments were conducted to obtain the practical value of the magnetic flux density.展开更多
As a 3-D display technology,stereoscopic imaging with lenticular lens sheet can only offer viewers the horizontal parallax.To reconstruct the 3-D image with parallax in both horizontal and vertical directions,the full...As a 3-D display technology,stereoscopic imaging with lenticular lens sheet can only offer viewers the horizontal parallax.To reconstruct the 3-D image with parallax in both horizontal and vertical directions,the full parallax technique with micro-lens array was proposed.But due to the fabrication constraints and cost concerns of the micro-lens array,application of the full parallax technique is restricted in practice.In this paper we revisited the lenticular sheet method and cross-lenticular lens array formed by two lenticular sheets overlapped orthogonally.By analyzing the optical properties of this cross-lenticular lens array,we found that it has reasonable imaging qualities as a conventional micro-lens array.Besides,due to the poor optical property of the outskirt area of the cross-lenticular lens,the cross-lenticular lens array has better crosstalk suppression capability than the conventional one.Based on the analysis,in this paper,we used the proposed lens array to reconstruct a 3-D image and verified its practicability.The cross-lenticular lens array was found feasible to take the full parallax technique into commercial applications,with comparable advantages in terms of low-cost and easy fabrication over a large area.展开更多
To obtain high cross-range resolution, the underwater 3-D acoustic imaging system usually requires a rectangular array with a great number of sensors and a large physical size. To reduce the sensor number and the arra...To obtain high cross-range resolution, the underwater 3-D acoustic imaging system usually requires a rectangular array with a great number of sensors and a large physical size. To reduce the sensor number and the array physical size simultaneously, this paper proposes a new underwater 3-D acoustic imaging approach based on a novel multiple-input multiple-output (MIMO) array. Specifically, the MIMO array is composed of four uniform linear arrays (ULAs) located on four sides of a rectangle. The transmitting array composed of two ULAs is located on a pair of opposite sides, and the receiving array composed of another two ULAs is located on the other two sides. Furthermore, narrowband waveforms coded with orthogonal polyphase sequences are employed as transmitting waveforms. When the subcode numbers in the polyphase coded sequences are sufficient, the MIMO array has the same 3-D imaging ability as a rectangular array, which has a two-time bigger size than that of the former. Consequently, the MIMO array can not only save a great number of sensors, but halve the array size, when compared to a rectangular array with the same cross-range resolution. Computer simulations are provided to demonstrate the effectiveness of the proposed imaging approach.展开更多
基金Supported by the National Key Basic Research and Development Program(973 Program)(2014CB046405)
文摘In this paper a new spherical actuator is designed and its advantages are compared to an existing spherical actuator, which function is limited by several design bottlenecks. First the output torque is too small. Second, the attitude is difficult to be accurately detected. The new three-dimen- sional magnetic pole array can solve these major problems. The new actuator features an outer rotor with multiple permanent magnet （PM） poles. Using an analytical solution and the finite element so- lution simulation, the feasibility of the approach is verified. A prototype was developed, tested, and experiments were conducted to obtain the practical value of the magnetic flux density.
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2010CB327702)
文摘As a 3-D display technology,stereoscopic imaging with lenticular lens sheet can only offer viewers the horizontal parallax.To reconstruct the 3-D image with parallax in both horizontal and vertical directions,the full parallax technique with micro-lens array was proposed.But due to the fabrication constraints and cost concerns of the micro-lens array,application of the full parallax technique is restricted in practice.In this paper we revisited the lenticular sheet method and cross-lenticular lens array formed by two lenticular sheets overlapped orthogonally.By analyzing the optical properties of this cross-lenticular lens array,we found that it has reasonable imaging qualities as a conventional micro-lens array.Besides,due to the poor optical property of the outskirt area of the cross-lenticular lens,the cross-lenticular lens array has better crosstalk suppression capability than the conventional one.Based on the analysis,in this paper,we used the proposed lens array to reconstruct a 3-D image and verified its practicability.The cross-lenticular lens array was found feasible to take the full parallax technique into commercial applications,with comparable advantages in terms of low-cost and easy fabrication over a large area.
基金supported in part by the Doctorate Foundation of Northwestern Polytechnical University(Grant No. CX201101)
文摘To obtain high cross-range resolution, the underwater 3-D acoustic imaging system usually requires a rectangular array with a great number of sensors and a large physical size. To reduce the sensor number and the array physical size simultaneously, this paper proposes a new underwater 3-D acoustic imaging approach based on a novel multiple-input multiple-output (MIMO) array. Specifically, the MIMO array is composed of four uniform linear arrays (ULAs) located on four sides of a rectangle. The transmitting array composed of two ULAs is located on a pair of opposite sides, and the receiving array composed of another two ULAs is located on the other two sides. Furthermore, narrowband waveforms coded with orthogonal polyphase sequences are employed as transmitting waveforms. When the subcode numbers in the polyphase coded sequences are sufficient, the MIMO array has the same 3-D imaging ability as a rectangular array, which has a two-time bigger size than that of the former. Consequently, the MIMO array can not only save a great number of sensors, but halve the array size, when compared to a rectangular array with the same cross-range resolution. Computer simulations are provided to demonstrate the effectiveness of the proposed imaging approach.
