FLYING SNAKE ROBOT
Overview
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Robots capable of maneuvering on land like Snake robots and in air like Quadcopters are beneficial for various applications. The individual dynamics of both robots are studied and their drawbacks are aimed to be overcome with a Flying snake robot while retaining their characteristics and advantages. This project included Design, Development and Control of SemiAutonomous Snake Robot Configurable into a Quadcopter (Flying Snake Robot). The design as well as the flight controller were implemented on the Flying Snake robot. The work had good theoretical results and idea was patented (Patent : Hybrid robot, Indian patent application number 201721020615, Dated: 13.06.2017)
Mechanical Design
The design includes eight actuators(Dynamixels) for snake locomotion and four brush-less DC motors, placed alternately to make the robot fly. (The design is modular and more links can be stacked together for more innovative designs) BLDC motors were placed selectively over the Dynamixels with horizontal axis of rotation such that the plane of symmetry of BLDC motor coincided with the horizontal axis of rotation. This allows no acting torque on the Dynamixels as BLDC produces upward thrust. Designing and Modelling of various links for actuators were done in Solidworks. Components like ESCs (to control BLDC motors), receiver, controllers, battery was placed in the links and the wires routes through them. The mass imbalance was dealt via changing the control strategy such that 2 motors on the side of heavier mass( due to battery) always run at higher speed than the other two to compensate for the extra mass.( for more information see the thesis)
Working Principle
The Component Flow Diagram and the Flow Chart for the working of the robot are shown by following figures.
SNAKE LOCOMOTION:The status of the channel 5 of the transmitter is continuously being monitored by a GPIO pin ofArduino. If it is found to be low, Arduino sends a signal to the OpenCM9.04 controller stating to perform snake locomotion. Now, three GPIO pins of Arduino are used to command OpenCM9.04 so as to perform a total of 8 snake motions on the basis of PWM signal receivedfrom different channels of the transmitter.These different gaits of the snake being performed include: Straight line , Caterpillar forward motion, Caterpillar backward motion, Clockwise rotation , Anti-clockwise rotation, Forward Lateral shifting, Reverse Lateral shifting and Square configuration. Due to mounted propellers, this is unable to do the Rotation Motion of snake, which arises as one of the drawbacks. Accordingly the different snake gaits are performed using the above mentioned equations. The video demonstration can be found below.
AS A QUADCOPTER: Snake achieves an square configuration . This symmetrical structure provides the ease to apply the dynamics of flight controller with BLDC motors. The dynamixel actuators maintain their torques during the flight motion. During this performance, channel 5 of the transmitter is continuously monitored and if it is found to be high then, Arduino reads and commands OpenCM9.04 to form square configuration for robust flight. Until this square formation is complete al BLDC actuators are non-active. Once the configuration is formed, signals to BLDC motors are sent through ESCs and controlled by
Arduino as per the incoming commanding values on Receiver's channels and thus a stable Semi-autonomous flight is achieved.
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Different Configurations for the Flying Snake