Reorientation and obstacle avoidance control of free-floating modular robots using sinusoidal oscillator

This paper presents that a serpentine curve-based controller can solve locomotion control problems for articulated space robots with extensive flight phases, such as obstacle avoidance during free floating or attitude adjustment before landing. The proposed algorithm achieves articulated robots to use closed paths in the joint space to accomplish the above tasks. Flying snakes, which can shuttle through gaps and adjust their landing posture by swinging their body during gliding in jungle environments, inspired the design of two maneuvers. The first maneuver generates a rotation of the system by varying the moment of inertia between the joints of the robot, with the magnitude of the net rotation depending on the controller parameters. This maneuver can be repeated to allow the robot to reach arbitrary reorientation. The second maneuver involves periodic undulations, allowing the robot to avoid collisions when the trajectory of the global Center of Mass (CM) passes through the obstacle. Both maneuvers are based on the improved serpenoid curve, which can adapt to redundant systems consisting of different numbers of modules. Finally, the simulation illustrates that combining the two maneuvers can help a free-floating chain-type robot traverse complex environments. Our proposed algorithm can be used with similar articulated robot models.