Improved hybrid A* path planning method for spherical mobile robot based on pendulum

This article proposes a modification of hybrid A* method used for navigation of spherical mobile robots with the ability of limited partial lateral movement driven by pendulum. For pendulum-driven spherical robots with nonzero minimal turning radius, our modification helps to find a feasible and achievable path, which can be followed in line with the low time cost. Because of spherical shell shape, the robot is point contact with the ground, showing different kinematic model compared with common ground mobile robots such as differential robot and wheeled car-like robot. Therefore, this article analyzes the kinematic model of spherical robot and proposes a novel method to generate feasible and achievable paths conforming to kinematic constraints, which can be the initial value of future trajectory tracking control and further optimization. A concept of optimal robot’s minimum area for rotation is also proposed to improve search efficiency and ensure the ability of turning to any orientation by moving forward and backward in a finite number of times within limited areas.

Research on novel spatial structure of power generation of spherical robot

Continuous energy supply is essential to spherical mobile robot in the Antarctic investigation. This paper puts forward energy harvesters that can generate electricity from the wind to achieve the long time and the long range exploration. The major contribution is to present the preliminary models of the energy harvester which uses the law of electromagnetic induction, and meanwhile the spatial structures about generating electricity are analyzed, and the influence of different structures on the power generation and efficiency will be obtained. In order to get the characteristics of power generation efficiency, this paper designs one element pipeline model and two element pipeline model, and then the motion of magnet in harvester will be simulated in different installed structures and wind speed. The varying rules of induced voltage are concluded at last. Finally, experiments are implemented based on the simulated model. The experimental results verify the dependability of different structural schemes of the robot and the validity of induced voltages’ varying rules. The results show that the induced electromotive force value obtained by the one element pipeline structure model is larger than the two element pipeline model, but the stability of the latter is better. Through the research in this paper, it can provide a basis for selecting a suitable spherical robot space structure according to the environmental conditions to improve the endurance.