Mantis: A Facade Cleaning Robot Inspired by Caterpillars

A New Class of Robots That Overcome Vertical Obstacles

Mantis is a new class of facade cleaning robots that are not only capable of autonomously navigating flat vertical facades but also moving over positive obstacles and kerbs. To this end, Mantis is equipped with a caterpillar-inspired linear actuator bar system which allows it to cross over obstacles on vertical facades with ease. Mantis is equipped with onboard sensors that enable the creation of real-time maps of the operating environment, health monitoring, and optimal cleaning paths.

The modules have track wheels to rotate and move on the facade. Each has an impeller, allowing the robot to stick on the facade. Each module is equipped with a microfiber cloth. The passive rotary system is designed to bring the center of mass close to the facade. It uses bearings to guide the system. Linear actuators are used to raise or lower the bar system or the modules. Parts are produced by 3D printing and laser cutting technologies, using materials such as PLA and acrylic.

When the robot reaches a positive obstacle on the facade, linear actuators on the bar system activate, raising the bar and preparing the robot to cross the obstacle. The first impeller switches off, and the first actuator activates, raising the first module. The robot then moves, making the module cross the obstacle. The module is lowered to the next facade, and its impeller is switched on. This process is repeated for the other modules until the entire robot has crossed over the obstacle.

This project, funded by the National Robotics Programme Office in Singapore, started in August 2017 and will end in August 2019. The aim of the project is to develop a new class of robots that target cleaning, maintenance, and inspection of built infrastructures.

One of the key challenges faced during the design process was the synthesis of a mechanism that allows the robot to move independently from the bar system. This requirement was further complicated due to size constraints and the need to make the center of mass as close to the surface of the facade as possible.

Mantis, a class of facade cleaning robot, is made up of three identical modules and a caterpillar-inspired linear actuator bar system. With the linear actuators, each of the impeller modules can be lifted off the facade, allowing Mantis to cross over obstacles on vertical facades with ease. Each module is also equipped with a passive rotary system, which allows it to rotate independently from others, enabling Mantis to traverse the facade. Mantis is also equipped with onboard sensors enabling the creation of real-time maps of the operating environment, health monitoring, and optimal cleaning paths.

The Mantis design was awarded Bronze in the A' Product Engineering and Technical Design Award in 2018. This prestigious award is bestowed upon outstanding and creatively ingenious designs that authenticate experience and resourcefulness. Esteemed for incorporating best practices in art, science, design, and technology, they exhibit strong technical and creative skills and contribute to quality of life improvements, making the world a better place.