In this paper, an improved FNN/PID compound control scheme is proposed to improve the ability of disturbance rejection and the stabilization accuracy of an aerial ISP.
For all of the three gimbals, the control systems are the same three-loop compound control structure, as shown in Figure 3.
The main control principle of the FNN/PID compound control scheme is that on the basis of the error and error changes of the input, the controller learning algorithm can adjust and update their weight constantly, which output a more suitable control amount for the current state of the system so that the output of the system is closer to the desired input [38].
When the improved FNN/PID compound control scheme is applied to the ISP, the accuracy should be taken into account; the fuzzy languages of each input variable are divided into seven segments.
The output of the improved FNN/PID compound control scheme is taken as the compensation of the constant PID parameters:
In order to solve the control problems of hydraulically driven shearer drum lifting, this paper proposed a new compound control method based on CMAC and fractional order PID (CMAC-[PI.sup.[lambda]][D.sup.[mu]]) controller to control the hydraulic system.
The structure and principle of the compound control method are schematized in Figure 5, where [r.sub.in] is the expected input, [y.sub.out] is the actual output, error is the control error, [u.sub.c] is the CMAC output, [u.sub.PID] is the [PI.sup.[lambda]][D.sup.[mu]] controller output, u is the total input of VCAHC, and RBF network is applied to tuning parameters ([K.sub.p], [K.sub.i], [K.sub.d], [mu], and [lambda]) of [PI.sup.[lambda]][D.sup.[mu]] controller, as described in Section 4.2.
As Figure 5 shows, a kind of compound control is generated through configuring CMAC in parallel with [PI.sup.[lambda]][D.sup.[mu]] controller.
Therefore, a new compound control method based on CMAC and fractional order PID controller has been proposed.