Flexible Time-Triggered Sampling in Smart Sensor-Based Wireless Control Systems

Sensors

Feng Xia¹ 

[1] College of Computer Science and Technology, Zhejiang University, Hangzhou 310027, China

关键词: adaptive sampling;    smart sensors;    flexible time-triggered;    wireless control systems;    sensor/actuator networks;   

DOI  :  10.3390/s7112548

来源: mdpi

【 摘 要 】

Wireless control systems (WCSs) often have to operate in dynamic environments where the network traffic load may vary unpredictably over time. The sampling in sensors is conventionally time triggered with fixed periods. In this context, only worse-than-possible quality of control (QoC) can be achieved when the network is underloaded, while overloaded conditions may significantly degrade the QoC, even causing system instability. This is particularly true when the bandwidth of the wireless network is limited and shared by multiple control loops. To address these problems, a flexible time-triggered sampling scheme is presented in this work. Smart sensors are used to facilitate dynamic adjustment of sampling periods, which enhances the flexibility and resource efficiency of the system based on time-triggered sampling. Feedback control technology is exploited for adapting sampling periods in a periodic manner. The deadline miss ratio in each control loop is maintained at/around a desired level, regardless of workload variations. Simulation results show that the proposed sampling scheme is able to deal with dynamic and unpredictable variations in network traffic load. Compared to conventional time-triggered sampling, it leads to much better QoC in WCSs operating in dynamic environments.

【 授权许可】

Unknown   
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