# Design and Implementation of Inverse Kinematics and Motion Monitoring System for 6 DoF Platform
## 5 Implementation  
The implementation block diagram of the platform is displayed in Figure 9. The mechanical structure of the platform was designed to carry a simulator cab of 1500 kg or heavier (Figure 10a). The platform mechanism was divided into upper and lower platforms. The six support arms of the platform achieved the 6 DoF stroke required by the simulator cab through crank arm rotation. Fisheye bearing joints were used to connect the upper end of the support arm to the upper platform, while the lower end of the support arm was coupled with the crank arm to drive the upper platform. The prototype of the crank mechanism is shown in Figure 10b. The dimensions are link length = 105 mm, support arm length = 835 mm, and crank length = 250 mm. The parameters of the motor are shown in Table 1. The gearbox ratio is 32.41. The servo motor was connected with a gearbox to magnify the torque output. A motion control card PMDK, produced by ICP Das Co., Ltd, was used with a 5-V PCI bus. The PMDK had six pulse input and output channels, six analog input and output channels, and various digital input and output channels. The PMDK was equipped with a two-wire FRnet IO module, which can be used for remote input and output control.  
Figure 8: Operation interface: (**a**) software setting and (**b**) channels display.  
Figure 9: The block diagram of the 6 DoF platform.  
The monitoring module is shown in Figure 11a,b. The operator opened the waterproof storage box, screwed one end of the wiring harness to the input and output connector and the other end to sensor a, and secured the measurement reference plates and three-section brackets in place (Figure 11a). Figure 11b displays the positions of the angular velocity meter and the gyroscope.  
The main program conducts the initial setup, thread enabling, and mode login of the platform. Figure 12a contains a flowchart of the implementation. Under the normal mode, the login mode can be selected using the human-machine interface. When the operator discovers an abnormal alarm or when maintenance personnel need to inspect the electric cylinders, they may select the maintenance mode via the interface. Data can be read and written via Internet transmission, and a thread of network modules is produced (Figure 12b). Operators can issue 6 DoF commands to the platform and transmit the 6 DoF commands to the platform computer by using Internet cable transmission.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Pole Number** & **8 Pole** \\ \hline Power dissipation & 5.0 kW \\ \hline Rated voltage & 220 V \\ \hline Rated load current & 25.9 A \\ \hline Rotor inertia & 0.00488 Kg-m\({}^{2}\) \\ \hline Rated speed & 2000 r/min \\ \hline Maximum speed & 3000 r/min \\ \hline Rated torque & 23.9 N.m \\ \hline Maximum torque & 71.6 N.m \\ \hline \hline \end{tabular}
\end{table}
Table 1: The parameters of the motor.  
Figure 10: 3D design drawing of the 6 DoF platform: (**a**) 6 DoF platform, and (**b**) crank arm mechanism.  
Figure 11: Photograph of the implementation system: (**a**) monitoring module and (**b**) upper platform.  
Figure 12: Flowchart of the implementation: (**a**) main program and (**b**) network module.