## 1 Introduction  
Different from direct quantitative determination of speed or torque, the road fluctuation is a kind of random vibration signal, which is difficult to collect [1]. As such, so the sinusoidal frequency signal is mainly used as input in an early-stage vibration experiment system [2]. After the experimental method of random signal power spectrum regeneration was invented by [PERSON] in the 1970s [2], the random vibration experiment platform for road simulation is developed gradually. The ultimate goal of remote parameter control (RPC) is to achieve the desired response of the SUT (system under test) in the real environment and reproduce the desired response in the laboratory environment, so that the SUT in the laboratory can achieve the same experimental effect as in the real environment. Therefore, the cost of experimental verification and the time of verification is reduced, as well as the experimental environment could be controlled [1; 2; 3]. In most cases, when the SUT is tested in a real environment, only response--but no input--can be obtained, and the response characteristics between the output and input of the SUT are also unknown. The RPC could obtain the desired output of the SUT by controlling the input of the SUT through transfer function (TF) estimation and iterative control. The most successful commercial applications of the reproduction system for the random vibration are RPC launched by MTS Corp. in 1977 [3], and TWR (time waveform replication) of LMS Corp. [4; 5], in which TWR is nowadays mainly used in MAST (multi-axial simulation table), thus RPC is not only used in MAST but also used in a RTS (road test simulator) [6]. There are other applications of road reproduction experiment as well, including ITFC (Iterative Transfer Function Compensation) launched by Schehck Corp. in 1979, and IDC (Iterative Deconvolution Control) launched by Faithurst Corp. in 1987. Their basic principle of iteration is more or less the same, which is RPC iterative control algorithm [7; 8]. The RPC algorithm mostly used in RTS is a kind of iteration algorithm based on a linear approximation system. Therefore in practical application, if the system is highly nonlinear, the iteration coefficient for correction needs special attention, otherwise the iteration may be easy to diverge [9; 10]. The most recent research on RPC algorithm are described herein: Multichannel decoupling used for multi-input iterative system control [11]; Combining multichannel electro-hydraulic servo online control with RPC offline iteration [12]; Using different frequency response characteristic estimation methods to obtain the estimation of frequency response function [13]; Proposing the method of value of drive correction coefficient based on the results to reduce the artificial participation and optimize the iterative robustness [8]; To optimize the iterative process by filtering the drive correction [9]; Proposing the method of updating the TF based on the system characteristics [14] and the method of system nonlinear and linear partial separation and identification [15] to improve the convergence of the system; Proposing the method of system linear partial experiment identification, nonlinear partial SVM (support vector machine) identification to obtain the accurate system transfer function [16]; Application on the parallel vibration table of various degrees of freedom [17; 18] and extending the application range to other vibration areas like a seismic simulation [6]. At present, most of the studies of RPC algorithm have made some progress on theoretical analysis like global convergence theory analysis, the theoretical basis of the correction coefficient applied to nonlinear system, and the relationship between frequency response characteristics of test system and frequency response bandwidth of the whole iterative process [8].