Design of Shape Shifting Robots
Mohan Rajesh Elara, SUTD

From residential floor cleaning to logistics delivery missions, robotics offer enormous advantages in improving productivity, efficiency and safety. However, designing these machines is challenging mainly attributed to the complex nature of the environments in which they operates. To this end, we are focusing our efforts on self-reconfigurable robots: artificial machines that possess ability to adapt their morphologies and behavior to overcome the complexities posed by the environment in which they operate. We have successfully demonstrated the efficacy and validity of these shape shifting concepts through a number of real world robotic applications.

Scorpio: A Bio-inspired Self-reconfigurable Robot for Urban Patrolling Missions

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Scorpio Crawling

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Scorpio Rolling

In most developed world due to rapidly aging workforce, hiring and retaining security personnel is becoming a major challenge. With a larger area to cover and lack of manpower, security personnel are hard pressed to ensure that no suspicious activities occur within the premises through patrolling. The ways that patrolling mission are run currently involves sending out security personnel to specific locations, there are some use of fixed sensors, and more recently use of robotic vehicles in order to automate security patrolling processes. Fixed morphologies of currently adopted robotic platforms highly restrict the types of terrain that these robots can navigate.

To this end, we are looking to nature to extract biological principles that help realize mechanisms, locomotion, sensing and autonomous behaviours that meet the expected design specifications and outcomes. Particularly, we are interested in previously unexplored Cerebrenus Rechenburgi, a species of huntsman spider for inspiration to realizing rolling-crawling locomotion. This spider species are found in the deserts of Morocco which in addition to crawling like any other spider species propels itself off the ground and moves its legs in a flic-flac somersault motion to go uphill, downhill or on level ground. In my research group, we are developing a Cerebrenus Rechenburgi inspired transformer robot, Scorpio with research focus on self-reconfiguration, autonomy and small scale. In terms of design, we have five primary iterations so far. The fifth generation of Scorpio is 100mm in diameter in its rolling form capable of rolling and crawling locomotion weighing about 200g. This platform is equipped with a camera, IMU and an onboard embedded controller that controls the gait generation and transformation. This robot can be operated in remote controlled and autonomous modes.

Hinged Tetro 2

The geometrical and physical characteristics of the terrain significantly impact the locomotion and navigation of these robotic platform. In autonomous mode, Scorpio’s software architecture uses a fusion of color, texture and orientation information to evaluate the terrain, classify it based on a set of pre-defined terrain types, and make appropriate decision on the choice of morphology.

Hinged-Tetro: A Shape Shifting Vacuum Cleaning Robot

Hinged-Tetro T Form Hinged-Tetro O Form Hinged-Tetro I Form

Current day vacuum cleaning robots are often highly constrained by the artefacts they interact with in the operating environment that greatly affect their cleaning performance. What we want to achieve is to be able to extend the cleaning capabilities of these robots than it is currently feasible. We are specifically interested in achieving self-reconfiguration with respect to interacting artefacts so as to achieve optimal cleaning performance while be able to autonomously shift between the available states.

Particularly, we are interested in previously unexplored Tetromineos, popular for their use in the video games Tetris for inspiration to realizing our selfreconfigurable cleaning robot, Hinged-Tetro. In terms of design, we have two primary iterations so far. Our Hinged-Tetro is able to transform itself into any of the seven one-sided tetrominoes which enables it to adapt to the cleaning environment. Hinged-Tetro’s body consists of four cubes connected by three revolute joints. Each cube is hollow with internal ribbing to minimize weight while maintaining strength. The hollow space encloses the vacuum suction unit. The blocks have a modular design, allowing many parts to be reused in the system. The shaping shifting capability of this robot enables it to efficiently clean room corners, narrow and complex furniture spaces that are almost impossible for current day cleaning robots.