## 2 Experimental Setup  
The experimental setup of the manipulator system is shown in Figure 1. The flexible manipulator used in this paper is a uniform aluminum cantilever beam and its properties are listed in Table 1. To fulfill the illustration of structural responses in the low frequency scope, instead of traditional PZT sensors, a full bridge strain gauge arrangement with the parameters detailed in Table 2, is attached on both sides of the beam as schematically illustrated in Figure 2. The strain gauge is chosen to lie near the root of the beam where the strain energy of the structure is the highest. Two PZT actuators with the properties listed in Table 3 are bonded onto both sides of the beam near the strain gauge. Moreover, a laser displacement sensor of Micro-Epsilon ILD 1402-50 (range: 50 mm, resolution: 5 \(\upmu\)m; Micro-Epsilon Messtechnik, Ortenburg, Germany) is used to measure the tip displacement of the manipulator. An electromagnetic vibrator (Sinocera Piezotronics INC, Yangzhou, China) is fixed to excite vibration of the beam as an external disturbance. The electromagnetic vibrator is located at 120.0 mm from the root of the beam. The real-time control system is implemented using a personal computer. A Data Acquisition (DAQ) device (National Instruments, Austin, OH, USA) of National Instrument PCI-6221(37 pin) is used for data acquisition and control output. The Lead zirconate titanate (PZT) actuator is driven by a power amplifier (Harbin Boshi Automation Co. LTD, Harbin, China), which can amplify the input signals from \(\pm\)5 V to \(\pm\)75 V. The strain signal is low-pass filtered and amplified through a strain amplifier, which can amplify the signal to a voltage range of \(\pm\)10 V. The output signal of the laser displacement sensor is conditioned to a voltage signal of 1-5 V by a signal conditioner. In addition, all the control algorithms are developed with the LabVIEW programming software (version 13.0, National Instruments, Austin, OH, USA).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Symbol** & **Quantity** & **Units** & **Value** \\ \hline \(l_{b}\) & length & mm & 1070.2 \\ \(uv_{b}\) & width & mm & 61.6 \\ \(l_{b}\) & thickness & mm & 2.1 \\ \(E_{b}\) & Modulus of elasticity & Gpa & 72 \\ \(p_{b}\) & density & Kg/m\({}^{3}\) & 2700 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Properties of the manipulator.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Symbol** & **Quantity** & **Units** & **Value** \\ \hline \(S_{S}\) & Gauge sensitivity & – & 2.08 \\ \(R_{s}\) & Resistance & \(\Omega\) & 350 \\ \(K_{s}\) & Amplification & – & 5000 \\ \(U_{o}\) & Supply Voltage & V & 4.0 \\ \(x_{s}\) & Location on the beam & mm & 30.0 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Properties of the strain measurement.  
Figure 1: Experimental setup of the smart manipulator system. PZT: Lead Zirconate Titanate; DAQ: Data Acquisition.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Symbol** & **Quantity** & **Units** & **Value** \\ \hline \(l_{p}\times w_{p}\times t_{p}\) & Length \(\times\) width \(\times\) thickness & mm & 60 \(\times\) 20 \(\times\) 0.8 \\ \(E_{p}\) & Modulus of elasticity & Gpa & 63 \\ \(\rho_{p}\) & Patch density & kg/m\({}^{3}\) & 7650 \\ \(d_{31}\) & Strain coefficient & C/N & \(-166\times 10^{-12}\) \\ \(x_{p}\) & Location on the beam & mm & 92.4 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Properties of the PZT patches.  
Figure 2: Block diagram of the experimental setup.