In-pipe inspection robots that use a screw drive mechanism move like a screw inside a pipe via three passive wheels. This paper develops mechanical and control models for an extended version of a screw robot that also controls steering.

After introducing the relevant literature, the bulk of the paper is about designing such a new robot, including its kinematics, dynamics, and control. The authors propose two methods to build the controller, one based on state vector feedback and the other on the linear quadratic regulator (LQR). Finally, they derive and test the block diagram of the controlling system in MATLAB, and implement the robot in the ADAMS simulator. The feasibility of the new steering mechanism is verified. The final conclusion is that this new model of screw robot has better control than previous versions and is able to follow given trajectories.

This is a typical paper on mechanics and control, that is, the algorithms used are from the literature and emphasis is on mathematical notation and extensive numerical simulations.

The paper is intended for researchers in mechanics and control. It is not appropriate for beginners; it lacks nonexpert-oriented pictures of the robot and the steering mechanism, and assumes readers are already familiar with the definitions and terminology. However, novices can read a few of the papers included in the references to make the content more accessible.