A TRIZ-Based Conceptual Design of an Automatic Footrest Stand to Enhance Lateral Stability of the Flexible Unicycle Prototype During Mounting and Dismounting

Abstract

This paper outlines the conceptual design of a support mechanism developed to improve the lateral stability of electric unicycles (EUCs), specifically the existing Flexi-UC design, during mounting and dismounting without compromising its compact and lightweight features. The study highlights the application of the Theory of Inventive Problem Solving (TRIZ), which enables the mechanism concept to be developed systematically according to the specified design requirements. Several TRIZ tools were applied, namely Functional Analysis, Cause-and-Effect Chain Analysis, Engineering Contradiction, and Physical Contradiction. As a result, Inventive Principle 7, the Nested Doll Principle, was selected and applied in developing the automatic stand design. Finite Element Analysis (FEA) was conducted to verify the automatic stand’s structural reliability. The results showed that the structure could safely support a maximum rider mass of 100 kg. The corresponding load produced a maximum von Mises stress of 66.723 MPa and a maximum deformation of 0.363 mm, both of which are below the allowable limits for mild steel. In addition, theoretical stability analysis indicates that the critical angle increases from ?6.01° without the stand to 10.9° with the automatic stand deployed, providing a significantly wider stability margin. Overall, the results demonstrate that the TRIZ-based approach is an effective method for generating conceptual designs that enhance the lateral stability of the Flexi-UC during mounting and dismounting.

ABSTRAK: Kajian ini menekankan aplikasi Teori Penyelesaian Masalah Inventif (TRIZ), membolehkan konsep mekanisme dibangunkan secara sistematik dalam memenuhi keperluan reka bentuk yang ditetapkan. Beberapa kaedah TRIZ telah digunakan iaitu Analisis Fungsi, Analisis Rantaian Sebab dan Akibat, Percanggahan Kejuruteraan dan Percanggahan Fizikal. Hasilnya, Prinsip Rekacipta 7 iaitu Nested Doll telah terpilih dan rekabentuk tongkat automatik telah digunakan. Analisis Unsur Terhingga (FEA) telah dijalankan bagi mengesahkan kebolehpercayaan struktur tongkat automatik tersebut, dan hasil analisis menunjukkan bahawa struktur tersebut mampu menampung beban penunggang maksimum seberat 100 kg dengan selamat. Beban tersebut menghasilkan tegasan Von Mises maksimum sebanyak 66.723 MPa dan ubah bentuk maksimum sebanyak 0.363 mm, kedua-duanya berada di bawah had yang dibenarkan bagi bahan keluli ringan. Selain itu, analisis kestabilan secara teori menunjukkan bahawa sudut kecondongan kritikal meningkat daripada ?6.01° tanpa sokongan tambahan kepada 10.9° dengan penggunaan tongkat automatik, sekaligus memberikan margin kestabilan yang lebih besar. Secara keseluruhan, dapatan kajian menunjukkan bahawa pendekatan berasaskan TRIZ merupakan kaedah berkesan dalam menghasilkan reka bentuk konseptual yang dapat meningkatkan kestabilan lateral Flexi-UC semasa proses naik dan turun.