| Description: |
There are life forms with incredibly effective locomotion mechanisms, sensing and computation capabilities, which are invaluable sources of inspiration for researchers. One of these bio-inspired designs is snake-like robots, which their small body cross-section, intrinsic stability, manoeuvrability and hyper-redundancy make them ideal for locomotion in challenging environments. However, design, modelling and control of a snake-like robotic mechanism for effective locomotion on surfaces with irregularities is a challenging task, which requires extensive research work. In this thesis, the design of a cost-effective modular snake robot is presented for generating pedal wave locomotion (undulatory motion in the vertical plane) on surfaces with irregularities, where the robot lifts its body parts to climb over obstacles. To design the motor torque measurement unit as a reliable and robust environmental sensing mechanism, an elastic element with the desired shape and stiffness has been designed and manufactured using easily accessible Polyurethane sheets and attached between the links and the motors to turn a conventional servo into a Series Elastic Actuator (SEA). The designed torque sensor is calibrated and the resolution and stiffness of the sensor are obtained to be 0.01𝑁. 𝑚 and 1.74 𝑁. 𝑚. 𝑟𝑎𝑑−1, respectively. In addition to the design of the SEAs, the snake robot modules are also designed and manufactured using cost-effective 3D printing method with Acrylonitrile Butadiene Styrene (ABS), which unlike existing snake robot designs are not equipped with wheels allows effective pedal wave locomotion on surfaces with irregularities. Experimentation results are also provided showing the effectiveness of the developed snake robot with SEAs for effective pedal wave motion generation. Moreover, this thesis introduces the equations of motion of modular 2D snake robots moving in vertical plane employing SEAs for the first time. The kinematics of such 2D modular snake robot is presented in an efficient matrix form and the ... |