Hydraulic drive unit (HDU) is a typical actuator, but the characteristic
of input delay hinders the application of many advanced control methods
in HDU. Firstly, in this paper, a mathematical model of HDU with input
delay is established and the parameters are identified. Then, aiming at
the input delay problem in HDU, a Smith estimated compensation model
predictive control (SECMPC) strategy is proposed. On the one hand, the
input delay state equation is employed to be a mathematical pattern for
the state observation and predictive model. However, the combination
between model predictive control (MPC) and Smith estimated compensation
(SEC) is realized, the system state at k+d (d is the time delay
coefficient) time is estimated in advance at k time to compensate the
delay of the state. And then the prediction model based on input delay
state equation is used for model prediction and rolling optimization.
Thus the delay system which is unstable is promoted to a stable system
without delay, and the effectiveness of SECMPC is proved with the HDU
experiment and simulation. The SECMPC have some guiding significance for
the control of systems with input delay.
Input-Delay Model Predictive Control of Inland Waterways Considering the Backwater Effect
