The research interest in mobile robots with independent steering wheels has been increasing over recent years due to their high mobility and better payload capacity over the systems using omnidirectional wheels. However, with more controllable degrees of freedom, almost all of the platforms include redundancy, which is modeled using the instantaneous center of rotation (ICR). This paper deals with a Tetris-inspired floor cleaning robot hTetro which consists of four interconnected differential-drive units. Each module has a differential drive unit which can steer individually. Differing from most other steerable wheeled mobile robots, the wheel arrangement of this robot changes because of its self-reconfigurability. In this paper, we proposed a path tracking controller that can handle discontinuous trajectories and sudden orientation changes for hTetro. Singularity problems are resolved on both the mechanical aspect and the control aspect. The controller is tested experimentally with the self-reconfigurable robotic platform hTetro, and results are discussed.

The next giant leap in the commercial robot cleaning market is cleaning the staircases and slope structures, leading to full-fledged building maintenance. So far, numerous robotic designs have been proposed to execute cleaning tasks on the staircase and slope surfaces. However, most existing robot designs could only perform cleaning in any one of the mentioned surfaces, often without any reconfiguring feature that expands its ability to perform the area coverage on both structures. In this letter, we introduce a novel robotic platform called s-Sacrr: A staircase and slope accessing reconfigurable cleaning robot that can traverse surfaces such as the floor, staircase, and slope by changing its morphology for area-coverage operation. s-Sacrr was designed as a three-stage traversing platform that consists of three modules connected with a vertical linear actuator which aids in reconfiguration as required during steps and slopes access. Specifically, the morphological transformation feature maintains the stability and evades the toppling effect of the robot. We evaluated the s-Sacrr robot’s smooth traversing and area-coverage ability on the staircase and slope surfaces. The experimental result demonstrates the s-Sacrr ability to access stairs and inclined surfaces.

HHoneycomb, a self-reconfigurable cleaning robot, is designed based on tiling theory, to overcome the significant challenges experienced by the fixed morphology cleaning robot. It consists of four regular hexagonal units and the units are connected by a planar revolute joint which helps in reconfiguration. This platform attains six distinct configurations (bar, bee, arch, wave, worm, and pistol) and these configurations have circular arcs and irregular concave and convex boundary that would help in accessing various obstacles in the cleaning space. This work addresses the mechanical design, system-level modeling, reconfiguration of the platform via hinged joint mechanism, mobility of the platform, polyhex based tiling set, and power consumption during reconfiguration. The strength of the mechanical structure is studied based on the structural analysis of the system using finite element method. Based on the natural frequency and deformation pattern, the proposed design is validated and proven to overcome structural failure and system resonance. The kinematics formulation of the platform during locomotion and dynamics of each block during reconfiguration are derived. The robotic system is modeled in Simscape multibody toolbox of Matlab and the mobility of the platform is studied using the numerical simulation. Based on the real-time current consumption of each joint during reconfiguration, the energy efficient configuration and tiling set are addressed.

Professional cleaning and safe social distance monitoring are often considered as demanding, time-consuming, repetitive, and labor-intensive tasks with the risk of getting exposed to the virus. Safe social distance monitoring and cleaning are emerging problems solved through robotics solutions. This research aims to develop a safe social distance surveillance system on an intra-reconfigurable robot with a multi-robot cleaning system for large population environments, like office buildings, hospitals, or shopping malls. We propose an adaptive multi-robot cleaning strategy based on zig-zag-based coverage path planning that works in synergy with the human interaction heat map generated by safe social distance monitoring systems. We further validate the proposed adaptive velocity model’s efficiency for the multi-robot cleaning systems regarding time consumption and energy saved. The proposed method using sigmoid-based non-linear function has shown superior performance with 14.1 percent faster and energy consumption of 11.8 percent less than conventional cleaning methods.