Polylactide materials present a promising alternative to petroleum-based polymers due to their sustainability and biodegradability, although they have certain limitations in physical and mechanical properties for specific applications. The incorporation of nanoparticles, such as layered silicate (clay), carbon nanotubes, metal or metal oxide, cellulose nanowhiskers, can address these limitations by enhancing the thermal, mechanicals, barriers, and some other properties of polylactide. However, the distinct characteristics of these nanoparticles can affect the compatibility and processing of polylactide blends. In the polylactide nanocomposites, well-dispersed nanoparticles within the polylactide matrix result in excellent mechanical and thermal properties of the materials. Surface modification is required to improve compatibility and the crystallization process in the blended materials. This article reviews the development of polylactide nanocomposites and their applications. It discusses the general aspect of polylactides and nanomaterials as nanofillers, followed by the discussion of the processing and characterization of polylactide nanocomposites, including their applications. The final section summarizes and discusses the future challenges of polylactide nanocomposites concerning the future material’s requirements and economic considerations. As eco-friendly materials, polylactide nanocomposites offer significant potential to replace petroleum-based polymers.

Steam mopping is an eco-friendly solution for cleaning and disinfecting floors, avoiding harsh chemicals or harmful UV lights. Currently, commercial steam mopping systems are manually operated, which is laborious and unsafe. This work presents the design methodology of a novel, eco-friendly autonomous steam mopping robot named ‘Snail’ for cleaning and disinfecting typical indoor floors, namely tile, carpet, concrete, vinyl, sealed wood, and rugs. Our work is mainly focused on (1) the mechanical system design, including the locomotion, steam dispenser, and mopping unit, (2) the hardware and software architecture, and (3) the motion control system’s design for smooth maneuverability and mitigating friction forces. A high-gain friction estimator is proposed, whose output is exploited by the motion controller to follow the desired path and compensate for the traction-based locomotion disturbances due to extensive mop contact with a rough-textured floor, such as carpet. The proposed autonomous steam mopping robot’s efficiency is validated with different floors with zig-zagging cleaning patterns, setting a minimum of 100 °C as the disinfecting steam criterion. Using the proposed motion control algorithm, we validate the smooth maneuverability, assuring the robot traverses with a given speed and follows the trajectory even on a rough carpeted floor. The cleaning efficiency is tested by removing hard stains, consuming less water, and faster wet floor drying. The robot used only one liter of water to clean a 5 ${\mathrm{m}}^2$ floor area, and the drying time was found to be four times faster than normal water mopping. The proposed steam mopping robot design is ideal for cleaning and disinfecting hospitals and eldercare centers, where hygiene is crucial, and promoting going green, avoiding harsh chemicals, and mitigating current cleaner labor concerns, including the risk of infection.

For glass façade cleaning, we developed a reconfigurable robot, Mantis-mini, with a dry cleaning mechanism and linear actuator based transitioning mechanism. It consists of three suction modules, connected by a support structure and each suction module has individual differential drive wheels with independent steering capability. This paper focuses on the detailed design of the platform, static structural analysis for and kinematic formulation. The adhesion performance of the suction module is evaluated using experiments, Computational Fluid Dynamics (CFD) simulations, and analytically formulated estimation. The suction pressure magnitude predicted from the simulations increases with suction impeller speed and agrees well with measurements and analytical calculation in terms of order of magnitude and qualitative trend. An adaptive proportional-integral (PI) controller is designed and implemented for regulating suction pressure and motion controller of the platform. The suction performance of the platform is validated through real-time experiments of the platform on the glass surface.

Liquid-carrying robots require slosh suppression methods to improve their performance. To design these systems requires effective slosh measurement. State-of-the-Art slosh estimation methods have limitations, which include solely handling unidirectional motion or relying on theoretical models. This letter proposes a novel sensor array for measuring sloshing in liquid-carrying mobile robots. The proposed system offers two key contributions: first, it enables comprehensive measurement and visualization of sloshing during omnidirectional movements, and second, it provides a compact and seamless integration into mobile robots, enabling them to mitigate the adverse effects of sloshing. The sensor system has been developed using 14 time-of-flight range sensors. The range sensors are connected to an Arduino Mega through I$^{2}$ C communication. A 3-D visualization method has also been developed to visualize the sloshing. The sensor array was integrated into a mobile robot for validation. Utilizing the 3-D visualization method, the sensor system can reconstruct the liquid surface with a sampling rate of 17.8 Hz. The experimental results confirm that the proposed sensor system effectively measures sloshing during omnidirectional movement of the robot.

Prototyping plays an important role in product design and has recently gained benefit from the rising popularity of 3D printing. It is to be expected that 3D printing will accommodate more materials, which need to be tailored to specific design requirements. Insights into heat transfer and fluid flows (thermo-fluid dynamics) in the printing process is thus essential to obtain favorable process parameters that can lead to high quality prints. In this work, polylactic acid (PLA) melt in Fused Filament Fabrication (FFF) 3D printing was numerically studied through Computational Fluid Dynamics (CFD) simulations, with a focus on the thermo-fluid dynamics of the strand deposition of the filament melt on the printer platform. The study was carried out by evaluating 6 printing cases, with a variation of 2 key process parameters, i.e., printing speed (30 and 45 mm/s) and platform temperature (310, 320, and 340 K). The simulation results showed that the free surface in the tip region of the strand has the most tendency to adhere to the printing platform heated at 340 K with the printing speed of 45 mm/s, as compared with other cases. This was affected by the lower dynamic viscosity in the region, relative to other cases, resulting from the high platform temperature and shear rate generated by the high printing speed.