CPG-based Locomotion Controller Design for a Boxfish-like Robot

Abstract

This paper focuses on a Central Pattern Generator (CPG)-based locomotion controller design for a boxfish-like robot. The bio-inspired controller is aimed at flexible switching in multiple 3D swimming patterns and exact attitude control of yaw and roll such that the robot will swim more like a real boxfish. The CPG network comprises two layers, the lower layer is the network of coupled linear oscillators and the upper is the transition layer where the lower-dimensional locomotion stimuli are transformed into the higher-dimensional control parameters serving for all the oscillators. Based on such a two-layer framework, flexible switching between multiple three-dimensional swimming patterns, such as swimming forwards/backwards, turning left/right, swimming upwards/downwards and rolling clockwise/counter-clockwise, can be simply realized by inputting different stimuli. Moreover, the stability of the CPG network is strictly proved to guarantee the intrinsic stability of the swimming patterns. As to exact attitude control, based on this open-loop CPG network and the sensory feedback from the Inertial Measurement Unit (IMU), a closed-loop CPG controller is advanced for yaw and roll control of the robotic fish for the first time. This CPG-based online attitude control for a robotic fish will greatly facilitate high-level practical underwater applications. A series of relevant experiments with the robotic fish are conducted systematically to validate the effectiveness and stability of the open-loop and closed-loop CPG controllers.

Towards a miniature self-propelled jellyfish-like swimming robot

“…1 Among underwater robots, swimming robots have significant potential for study of marine life, monitoring oceanic environments, and underwater operations. [2][3][4][5][6][7] As a specific sea creature, jellyfish has a soft body, which is found in the waters all over the world. Owing to low metabolic rate, jellyfish has the ability to move vertically without expending much energy, while it passively depends on ocean current, tides, and wind for horizontal movements.…”

Design and Control of an Agile Robotic Fish With Integrative Biomimetic Mechanisms

“…However, the merits of the caudal fins had not been explored for the driving limitation of IPMC. There have also been many developed fish-like prototypes with dual pectoral fins, including the MPF-like robotic fishes [7][8][9] and BCF-like robotic fishes [12,40,41]. In the MPF-like robotic fishes, the long base of dual pectoral fins usually requires more DoFs, which increases the complexity of the structure.…”

Speed evaluation of a freely swimming robotic fish with an artificial lateral line

“…The robot is controlled by an artificial CPG network whose stability has been strictly proved in our previous paper [24]. The linear CPG model takes the forṁ…”

“…In our previous work, we have developed a boxfish-like robot to study fishlike locomotion [24]. Hydrodynamic simulations and on-site experiments with the robot have demonstrated that our robot can always mimic the freely swimming locomotion of its biological counterpart [13].…”