Implementation of Caterpillar Inspired Rolling Gait and Nonlinear Control Strategy in a Spherical Robot

This paper presents a novel Central Pattern Generator （CPG） based rolling gait generation in a small-sized spherical robot and its nonlinear control mechanism. A rhythmic rolling pattern mimicking Pleurotya caterpillar is produced for the spherical robot locomotion. A synergetically combined feedforward-feedback control strategy is proposed. The feedforward component is generated from centrally connected network of CPGs in conjunction with nonlinear robot dynamics. Two nonlinear feedback control methods namely integral （first order） Sliding Mode Control （SMC） and High （or second） Order Sliding Mode Control （HOSMC） are proposed to regulate robot stability and gait robustness in the presence of matched parameter uncertainties and bounded external disturbances. Design, implementation and experimental evaluation of both roll gait control strategies for the spherical robot are done on smooth （indoor） and irregular （outdoor） ground surfaces, The performance of robot control is quantified by measuring the roll angle stability, phase plane convergence and wheel velocities. Experimental results show that proposed novel strategy is efficient in producing a stable rolling gait and robust control of a spherical robot on two different types of surfaces. It further shows that proposed high HOSMC strategy is more efficient in robust rolling gait control of a spherical robot compared to an integral first-order SMC on two different ground conditions.

Design innovation of mesoscale robotic swarms:applications to cooperative urban sensing and mapping

Development of mesoscale robots is gaining interest in security and surveillance domains due to their stealth and portable nature in achieving tasks.Their design and development require a host of hardware,controls,and behavioral innovations to yield fast,energy-efficient,distributed,adaptive,robust,and scalable systems.We extensively describe one such design and development process by:(1)the genealogy of our embedded platforms;(2)the key system architecture and functional layout;(3)the developed and implemented design principles for mesoscale robotic systems;(4)the various key algorithms developed for effective collective operations of mesoscale robotic swarms,with applications to urban sensing and mapping.This study includes our perception of the embedded hardware requirements for reliable operations of mesoscale robotic swarms and our description of the key innovations made in magnetic sensing,indoor localization,central pattern generator control,and distributed autonomy.Although some elements of the design process of such a complex robotic system are inevitably ad-hoc,we focus on the system-of-systems design process and the component design integration.This system-of-systems process provides a basis for developing future systems in the field,and the designs represent the state-of-the-art development that may be benchmarked against and adapted to other applications.