书籍类别中的标题页不起作用

Question

我最近开始接触 latex，并且正在使用 overleaf。
下面是 main.tex

\documentclass[10pt]{book}
\usepackage{makeidx}
\usepackage[utf8]{inputenc}
\usepackage{graphicx}
\usepackage{titling}

\title{Sequential Decoding Of Lower Limb Movements Using Non-Invasive Brain 
Computer Interface}
\setlength{\droptitle}{-14em}
\vspace{-80pt}
\date{\vspace{-5ex}}
\author{\vspace{-5ex}}

\begin{document}
\frontmatter
  \input{titlePage.tex}
\end{document}

以下是 titlePage.tex：

\begin{titlepage}
  \maketitle
  \begin{center}
    \text{Thesis\\Submitted in partial fulfillment of the requirements 
          of\\BITS F421T Thesis}
    \\[1\baselineskip]
    \text{By}\\
    \medskip
    \textbf{Roshan Sivakumar\\2016A3TS0836H}\\
    \bigskip
    \text{under the supervision of}\\
    \bigskip
    \textbf{Dr.Elahe Abdi \\Mechanical and Aerospace Department \\Monash 
            Univesity, Clayton}\\
    \medskip
    \textbf{Dr. Yan Wong \\Electrical and Computer Engineering Department 
           \\Monash University, Clayton}\\
    \medskip
    \textbf{\&}\\
    \medskip
    \textbf{Dr. BVVSN Prabhakar Rao \\Electrical Engineering Department 
            \\BITS Pilani, Hyderabad}\\
    \\[3\baselineskip]

    \graphicspath{{Images/}}
    \begin{figure}[htp]
      \centering
      \includegraphics[width=4cm, height=5cm]{logo}
      \label{fig:bitsLogo}
    \end{figure}

    \medskip
    \textbf{BIRLA INSTITUTE OF TECHNOLOGY AND SCIENCE, PILANI\\HYDERABAD 
            CAMPUS}
  \end{center}
\end{titlepage}

我似乎无法弄清楚为什么 titlePage 没有显示在输出中。但只显示了标题。此外，任何有关我使用的命令的评论都将不胜感激。