Performance improvement for networked control system with nonlinear control action

Great versatility can be achieved with the use of wireless networked control, but communication errors and channel congestion must be taken into account. Random delays and packet dropouts can degrade control performance. This paper describes a controller design strategy to reduce the effects of sensor data loss in control feedback loops. A fuzzy controller is compared to a classic PID controller to verify reference tracking performance in the presence of packet dropouts. Losses are treated by two common compensation methods: zero input and hold input. To avoid adjustment bias for any of the controllers, tuning is performed by a genetic algorithm that minimizes the difference between actual and desired output. The obtained fuzzy controller presents better tolerance to higher losses, which is observed in the reduction of response error peaks. Hard clipping the classic PID output also improves performance.