Bio-Inspired Robots for Surveillance and Assistance

Biomimicry is a nature-inspired concept which has the advantage of overtime evolution. The Theo Jansen Mechanism is one of the mechanisms that mimics the leg motion of a human. In robotics, while in comparison with the wheeled robot, bio-inspired mechanism-based robots can have better traction and stability on uneven, slippery surfaces as well as can also navigate over small obstacles and rough terrain. This study aims to design and develop a bio-inspired robot with the objective to walk on various terrains. The authors used the Theo Jansen Mechanism developed in the early 1990s by a Dutch artist Theo Jansen and modified the same by converting binary linkage to ternary linkage that increases the stability of the mechanism and reduces the jerk. Numerous iterations are performed by modifying the link dimension to attain the optimized step height, stride length, and foot trajectory. The selection of the optimized values is carried out based on the acceleration values that are acquired from the motion study. After finalizing the dimension of various linkages, new geometrical changes are performed, except the changes in the dimension to transform various plane conventional mechanisms into a single plane-modified mechanism. To identify whether the modified mechanism will be able to sustain its self-weight and the partial weight of the whole robot, static structural analysis is conducted. The material chosen for this analysis is the acrylonitrile butadiene styrene (ABS); it comprises good tensile strength, impact resistance, and toughness and good chemical resistance from acids, alkalis, and oils as well as heat resistance from high temperature. A total of eight legs are developed using the modified mechanism for complete motion. The static structural analysis of the full robot is carried out for the total weight of the robot, including all mounting. The prototype of the robot is 3D-printed using fused deposition modeling (FDM) technology using the ABS material. As a part of electronics, ultrasonic sensors are used for obstacle avoidance, which sense the object and send the command to the Arduino Uno, a microcontroller. Three ultrasonic sensors, two in front and another one at the back side, are mounted over the separate servo motors for the same purpose. Also, a motor driver is used to operate two DC motors for the movement of the robot, and a Bluetooth module is used to command the robot using any Bluetooth-enabled device. All the electronics are powered with a 12V LiPo battery. The testing of the prototype is carried out on various terrains, namely, sand, concrete, wooden, tiles, and bitumen roads. This robot and the mechanism have a scope in wheelchairs, the development of a surveillance robot to assist the Indian Armed Forces, to treat the patient having cerebral palsy, to develop of a robot to assist the National Disaster Response Force (NDRF), Space Exploration, for conduction of precision Agriculture, and in the entertainment, industry like in a theme park.