To improve the dynamic quality of the PMSM servo system, a generalized super-twisting sliding mode control strategy based on the sinusoidal saturation function is proposed in this paper. Firstly, the dynamic mathematical model of PMSM is established. Then, a sliding mode variable structure speed controller is designed based on the generalized super-twisting algorithm. To weaken the chattering phenomenon, the sinusoidal saturation function is used instead of the sign function. Finally, the effectiveness of the proposed strategy was verified by MATLAB/Simulink simulation platform and compared with GSTA-SMC, STA-SMC and SMC based on exponential reaching law, the proposed strategy improved the response speed and immunity of the system while reducing chattering.
Breathing monitoring is important in the health and sports area. In this paper, a wireless self-powered health system for breathing monitoring is designed using the piezoelectric devices and buckled n-shape and L-shape structure. A cotton belt is used to tie the system to the chest and deliver the force stimulated by the chest cavity enlargement caused by the breathing, which can be collected and measured based on the three-dimension n-shape and L-shape structure. Three hard lead zirconate titanate (PZT) patches are used as the energy source to support the sensing circuit and soft piezoelectric polyvinylidene fluoride (PVDF) works as the sensor to measure the stretching force, which are placed at the gap between the 3D-printed n-shape and L-shape structure, making the measurement more precise. Breathing signal comparison between commercially used battery-powered respiration belts shows the efficiency of the piezoelectric devices on the accuracy, precision, and recall factors. The system is also used in practical experiments and it is found that the intense actions have a similar peak-peak value of breathing wavefront but a much higher frequency of respiration. This design can be used in health monitoring and sports training, which also shows the potential of data acquisition for disease diagnosis applications.
This paper presents an FPGA-based Montgomery modular multiplier for implementing high-throughput RSA cryptosystems. First, we propose a variable segmentation Montgomery modular multiplication (VSMMM) algorithm which enables the radix of the multiplier and the multiplicand adapt to any given datawidth. Then, to make trade-offs among latency, area and throughput, we design a dual-path fully concurrent MMM architecture based on VSMMM algorithm. As a case study, a RSA processor has been implemented using the proposed method. Experimental results show that the proposed MMM multiplier and RSA processor achieve much higher throughput than existing works.
A broadband static frequency divider fabricated in a 165GHz ft 0.8μm InP DHBT process is described. Capacitive degeneration technique is adopted, extending the operating bandwidth with little increase in power consumption and area occupancy. The device characteristics are analyzed to achieve high device ft utilization. The chip occupies 0.484mm×0.44mm and consumes 380mW from dual supplies of -2.5V and -3.5V. The measured input-referred self-oscillation frequency (SOF) is 56GHz, and the output power locates in -5.87∼1.87dBm. With single-ended sine-wave input, the divider is operational in 2∼62GHz, exhibiting a 0.36-ft frequency range.