雙輪倒單擺助行車之多迴圈去耦合控制

Abstract

本論文開發一套可作為輔具機器人之雙輪倒單擺(two-wheeled inverted pendulum, TWIP)系統。此系統具有兩種模式：雙輪倒單擺模式和輪椅模式。在雙輪倒單擺模式中，我們分別運用牛頓法及拉格朗日法推導系統非線性模型，再以手推及MATLAB將模型線性化得到系統轉移函數矩陣，最終則運用去耦合化方法，將MIMO系統簡化成平衡與轉向兩個獨立的SISO系統，可以分別進行控制器設計。在機構變形上，透過摺疊機機構設計與精簡硬體配置，賦予此系統擁有雙輪倒單擺與輪椅兩種模式的變換。此外，整合多種次系統，將其各別功能獨立運作，其中包含馬達系統、訊號接收系統、無線通訊系統等，當其中模組失能時，並不會影響其他模組運作，做到系統模組化。 在雙輪倒單擺模式，我們以PID控制、強韌控制及LQR控制理論，分別針對平衡以及轉向系統進行控制器設計，以性能指標量化數據，比較控制性能上的差異。首先，在平衡及轉向兩個單迴圈控制架構下，分別探討PID控制器的三個增益值對系統的影響、強韌控制中權重函數調整方法、及LQR控制中權重設計對整體系統之影響。最後則提出混合控制策略，以平衡PID控制搭配轉向強韌控制，改善雙輪倒單擺系統性能綜合表現。 在輪椅模式，我們以無線通訊系統連結智慧型手機控制，將輪椅即時資訊顯示在使用者介面上，同時亦可藉由智慧型手機上的虛擬搖桿控制輪椅的移動，並設計虛擬變速滑桿，使得輪椅可以自由改變移動速度。因為平台輕巧且機動性高，所以此系統不僅能當輪椅使用，亦適合搬運各式物件，甚至有50公斤以上的載重能力。

This thesis proposes a two-wheeled inverted pendulum (TWIP) system that can be used as an auxiliary robot. This system includes two modes: the TWIP mode and the wheelchair mode. In the TWIP mode, we applied the Newton Second Lawand the Lagrange’s method to derive the nonlinear model of the system. Then we linearised the model by hand-derivation and MATLAB to establish the multivariable linear model of the TWIP system. Finally, the multivariable model was decoupled and simplified into two single-input single-output(SISO) systems, so that balancing and steering control design can be carried out independently. In the deformation mechanism, we designed the folding mechanism and compact hardware configuration to transform the system between the TWIP and wheelchair modes. In addition, the system was modulised so that one module’s failure will not affect the operation of other subsystems. In the TWIP mode, we applied the PID control, robust control, and LQR control theorems to design the balancing and steering controllers. We dissussed the effects of the PID gains, the weight functions of the robust control, and the LQR weightings on system performance . Based on quantitative comparison on system performance, we proposed a hybrid control strategy that integrated PID control for the balancing loop and robust control for the steering loop to improve the overall performance of the TWIP system. In the wheelchair mode, the wireless communication system was connected to a smartphone, so that the real-time information of the wheelchair can be displayed on the user interface. Furthermore, the wheelchair can be operated by the virtual joystick on the smartphone. The machine can be used as a wheelchair or a carrier with a load capacity of 50 kg.