虛擬實境動態模擬系統之即時嵌入式控制單板研製

Abstract

電子產品朝向輕薄短小的設計概念邁進乃是近年來硬體發展的趨勢，而嵌入式系統因具有精簡、整合、體積小的特性而被廣泛的應用到控制相關領域裡。在本論文裡有效的應用上述之嵌入式系統優點在虛擬實境的硬體研發上，將整個軟硬體控制單元用一塊可獨立運作的控制單板來實現。 在此控制單板的硬體設計裡，主要包含以StrongARM微處理器為核心的嵌入式單板，及由此單板上的Data Bus和Address Bus擴充出來的12位元數位類比轉換介面卡，在與VR場景端的通訊上用TCP/IP來傳送六軸姿態，另一端與運動平台溝通的介面則是透過數位類比轉換介面卡。整個嵌入式系統扮演的是一個動態場景與運動平台間的溝通橋樑，負責把數位的動態資料轉換成平台所接受的軸電壓以對應腳長，並當作控制演算法的運算平台。 嵌入式系統的軟體系統方面，本論文將屬於應用軟體層的網路連線程式與控制程式等應用程式整合，搭配高穩定性、具多工能力且網路功能強大的ARMLinux作業系統，並用模組化驅動程式的設計概念，自行撰寫數位類比轉換介面卡的驅動程式載入核心，其處理效率與功能等於一塊單板電腦，可直接取代原來體積龐大的工業電腦。

This work integrates the hardware and software of embedded control system into a single board with embedded OS for the control of a VR motion simulator. The board is standalone and capable of replacing a control computer directly. Our hardware architecture includes an ARM-based mother board, a set of analog/digital interface, and a TCP/IP ethernet card. The circuit of analog/digital interface was designed by ourselves for transferring digital data to analog or vice versa. This analog/digital converter offers an interface between motion platform and simulation data of the VR Server. The whole embedded control system is responsible for receiving simulation data from VR Server by TCP/IP network interface, and performing some control algorithims to motivate the motion platform through the analog/digital converter. As for the system software, we design an analog/digital device driver for our analog/digital converter, and then port the application of networking and control algorithms in embedded operation system(OS) --ARMLinux. The device driver is developed in module, so we can insert it in the OS kernel without rebooting. In the experiment, we find out using the embedded control system mentioned above has many benefits. Such as modulization, simple hardware, and open source OS. Therefore, we conclude that embedded hardware/software system could be a trend for controlling the motion platform in a VR-based motion simulator.