Yan-An Yao

An Omnidirectional Rolling 8U Parallel Mechanism

A novel 8U (universal joint) parallel mechanism, being able to do omnidirectional rolling motion is proposed in this paper. This mobile mechanism owns the priority of simple structure and rolling easily on terrains with loose soil, dirt or sand with only a few actuations. Its spatial closed compact structure is described firstly. In addition, the omnidirectional locomotion accompanied with DOF (degree of freedom) alternation between one and two is revealed by mobility analysis. After that, the feasibility of rolling motion is verified theoretically by stability analysis. Finally, the omnidirectinoal rolling motion is testified both by virtual and prototype experiments.

A rolling mechanism with two modes of planar and spherical linkages

A novel deformable rolling mechanism is proposed in this paper. The mechanism can switch between two modes: a planar linkage mode and a spherical linkage mode. In the planar linkage mode, the mechanism rolls like a planar four-bar mechanism and moves along a straight line. In the spherical linkage mode, the mechanism rolls as a spherical four-bar mechanism and moves along a polygon. A standing posture, which likes an upright pyramid, of the rolling mechanism is also identified. After the description of the novel mechanism, the kinematic analysis of the mechanism is presented, and appropriate control strategies are proposed. Then, the rolling conditions of the mechanism are investigated based on the zero-moment-point theory. Finally, the various modes of the mechanism are verified by both simulations and prototype experiments.

Design and locomotion analysis of a novel deformable mobile robot with worm-like, self-crossing and rolling motion

This paper presents a novel deformable mobile robot with five degrees of freedom (DOFs). The robot contains two equivalent expandable triangular platforms connected by three equivalent chains. Each platform is a regular triangle with a single DOF. Each chain consists of two links and three joints (one spherical joint at the middle of a chain, and one revolute joint at each end of the chain). Through kinematic and locomotion mode analysis, the robot exhibits three motion modes: worm-like, self-crossing, and rolling modes. The worm-like and self-crossing modes can be used for narrow passages (e.g., pipelines, holes, and caves). The rolling mode has three different directions at the initial state. By switching between these, the robot can operate on rough ground. To verify the locomotion modes and functionality of the robot, the results of a series of experiments performed on a manufactured prototype are reported.

An agile assistant robot integrating operation and rolling locomotion

Purpose The purpose of this paper is to propose an agile assistant robot to be used as a mobile partner with two rotational motions and one translational motion. This robot possesses the rolling function and three operating abilities to assistant human beings in the industrial environment. Design/methodology/approach The main body of the robot is a typical 4-RSR (where R denotes a revolute joint and S denotes a spherical joint) parallel mechanism. The mechanism can reach any position on the ground by two rolling modes (the equivalent Watt linkage rolling mode and the equivalent 6R linkage rolling mode), and the robot can work as a spotlight or a worktable in operating modes at the target location. The mobility, rolling modes, operating modes and kinematics are analyzed. Findings Based on the results of kinematics of this assistant robot, the upper platform of the 4-RSR rolling mechanism has two rotational motions and one translational motion which can be used in the industry. The proposed concept is verified by experiments on a physical prototype. Practical implications This paper also discusses the application to industrial cases where cooperation between workers and robots is required. Originality/value The work presented in this paper is a novel exploration to apply parallel mechanisms to the field of assistant rolling robots. It is also a new attempt to use the rolling mechanism in the field of mobile operating robots for industry tasks.

Design and Rolling Analysis of a Novel Deformable Polyhedron Robot

In this paper, a new rolling robot is proposed. The mechanism of the robot consists of eight links with three degrees of freedom (DOFs). The shape of each link of the robot is an equilateral triangle. The robot realizes its direction switching function by deforming into different modes of planar parallelogram mechanisms (PPM). In any deterministic mode, the robot can roll on the ground. The motion of the robot is studied based on the kinematic and zero moment point (ZMP) analyses. Though the robot has three DOFs, we show that it can realize flexible mobility via direction switching and rolling functions with two DOFs and one DOF, respectively. A prototype robot was manufactured. A series of simulations and experiments done using this prototype is reported, verifying the feasibility of the design.