Yanheng Zhang

Mechanical analysis about the spherical mobile robot on the moon environment

In this paper we establish mechanical model of the interaction between spherical mobile robot and lunar soil under the moon environment. Two cases are considered: 1.static case in which the spherical robot sits stationary on the moon surface, 2.dynamic case in which the spherical robot rolls over the moon surface with a constant forward speed. Curves of mathematical model is obtained by the software of Matlab. Then we create the model of lunar soil and the spherical robot in the software of ANSYS. We obtain some difference datas about the relationships between the shape of lunar soil and carrying capability of the spherical robot. We obtain curves with these datas by Matlab curve fitting. Compare curves obtained by Matlab with curves obtained by ANSYS and Matlab curve fitting we can see that these two groups of curves are broadly consistent with each other. These simulation results verify the validity of the mathematical model.

Motion Analysis of a Spherical Robot with Climbing Ability

For the problem that the climbing ability of existing spherical robots are not strong enough,a new spherical robot mechanism is designed.There are two extendable arms fixed to the spherical body in the direction of bodys long axis. When climbing a slope of great gradient,the arms extend and support the body on the road.After arms extension,the robot is driven by motor directly,relying no longer on the pendulum.Then,analysis and comparison of climbing ability before and after arms extension are made,and the dynamic model of linear motion is estabUshed when robot climbing,also the path planning after arms extension is analyzed.Finally,the accuracy of the mechanical model is verified by simulation and tests.

Development of a spherical aerial vehicle for urban search

With the ability to provide close surveillance in narrow space or urban areas, spherical aerial vehicles have been of great interest to many scholars and researchers. The spherical aerial vehicle offers substantial design advantages over the conventional small aerial vehicles. As a kind of small aerial vehicles, spherical aerial vehicle is presented in this paper. Firstly, the unique structure of spherical aerial vehicle is presented in detail. And then as the key component of the spherical aerial vehicle, the meshed spherical shell is analyzed. The shell is made of carbon fiber and is used to protect the inner devices, so the deformation of the shell is analyzed and simulated. Then the experimental results verify the above analysis and the composite carbon fiber material makes the mesh spherical shell small deformation. Considering the whole vehicle has a shell outside, the lift affect of the meshed spherical shell is analyzed. The simulation and experiment results are basically consistent with theoretical analysis, and the impact of the meshed shell has small resistance for the airflow through the sphere.

Design of an Aerostatic Thrust Bearing with Pressure-equalizing Grooves

To solve the problem in the space robots microgravity simulation experiment that lateral interference force/moment exists and the workbench is uneven,a high load capacity,high stiffness round aerostatic thrust bearing with circumferential and radial pressure-equalizing grooves is designed and manufactured,and its load capacity is modeled and numerically analyzed using deformational Reynolds equation.In order to validate the theoretical calculation results,simulation analysis using Fluent is carried out to get the load capacity characteristics,and the influence of the impact created by the high pressure gas on the load capacity is analyzed.Finally,an experiment about the bearings load capacity characteristics is performed on the standard test platform,and the result is compared with the data of bearing without grooves.It turns out that the structure design and theoretical analysis are correct.

Decoupled Sliding Mode Control for the Climbing Motion of Spherical Mobile Robots

Based on the equivalent control method and Lyapunov function technique, a decoupled sliding mode control approach is presented for stable control of the climbing motion of spherical mobile robots with sliding mechanics. At first the dynamic equations of the climbing motion of a spherical mobile robot are derived based on the Euler-Lagrange equation, and the equilibrium conditions of the climbing state are then analyzed. Combining the feature of the dynamic model, a decoupled sliding mode controller is proposed and the asymptomatic stability of the system is theoretically analyzed. Finally, the proposed control approach is applied to a spherical mobile robot and simulation results verify the validity of the proposed control approach.

Manipulability analysis of a two-link space robot using differential geometry method

Space robot is a special robotic system which is expected to perform important tasks in space, like servicing satellites. But any motion of robotic manipulator will disturb its supporting vehicle in space due to the dynamic coupling. Moreover, the evaluating method of manipulability used on ground can not be directly applied to the space robot. A volume element concept is developed to evaluate the manipulability and disturbance of a space robot system. This paper shows the application of volume element method in two-link planar space robot. The volume element method is a new theoretical approach for the research and analysis of space robot system.