Design, Implementation and Control of an Amphibious Spherical Robot

We proposed and implemented a leg-vector water-jet actuated spherical robot and an underwater adaptive motion control system so that the proposed robot could perform exploration tasks in complex environments.Our aim was to improve the kinematic performance of spherical robots.We developed mechanical and dynamic models so that we could analyze the motions of the robot on land and in water.The robot was equipped with an Inertial Measurement Unit(IMU)that provided inclination and motion information.We designed three types of walking gait for the robot,with different stabilities and speeds.Furthermore,we proposed an online adjustment mechanism to adjust the gaits so that the robot could climb up slopes in a stable manner.As the system function changed continuously as the robot moved underwater,we implemented an online motion recognition system with a forgetting factor least squares algorithm.We proposed a generalized prediction control algorithm to achieve robust underwater motion control.To ensure real-time performance and reduce power consumption,the robot motion control system was implemented on a Zynq-7000 System-on-Chip(SoC).Our experimental results show that the robot’s motion remains stable at different speeds in a variety of amphibious environments,which meets the requirements for applications in a range of terrains.

A Fuzzy PID Algorithm for a Novel Miniature Spherical Robots with Three-dimensional Underwater Motion Control

We proposed and developed a small bionic amphibious spherical robot system for tasks such as coastal environment monitoring and offshore autonomous search and rescue.Our third-generation bionic small amphibious spherical robots have many disadvantages,such as the lack of maneuverability and a small operating range.It is difficult to accomplish underwater autonomous motion control with these robots.Therefore,we proposed a fourth-generation amphibious spherical robot.However,the amphibious spherical robot developed in this project has a small and compact design,with limited sensors and external sensing options.This means that the robot has weak external information collection capabilities.We need to make the real time operation of the robot's underwater motion control system more reliable.In this paper,we mainly used a fuzzy Proportional-Integral-Derivative(PID)control algorithm to design an underwater motion control system for a novel robot.Moreover,we compared PID with fuzzy PID control methods by carrying out experiments on heading and turning bow motions to verify that the fuzzy PID is more robust and exhibits good dynamic performance.We also carried out experiments on the three-dimensional(3D)motion control to validate the design of the underwater motion control system.