Jinyan Shao

Leader-Following Formation Control of Multiple Mobile Robots

This paper presents a framework for controlling groups of autonomous mobile robots to achieve predetermined formations based on leader-following approach. A three-level hybrid control architecture is proposed to implement both centralized and decentralized cooperative control. Under such architecture, we decompose the global-level formation control problem of N robots into decentralized control problems between N-1 followers and their designated leader. In the leader-follower control level, two basic controllers are proposed to make the following robot keep relative position with respect to the leader and avoid collisions in the presence of obstacles. Then, graph theory is introduced to formalize specified formation patterns in a simple but effective way, and two types of switching between these formations are also proposed. Numerical simulations and physical robot experiments show the effectiveness of our approach

A tracking controller for motion coordination of multiple mobile robots

This paper presents a new method for controlling a group of nonholonomic mobile robots to achieve predetermined formations without using global knowledge. Based on the dynamic leader-follower model, a reactive tracking controller is proposed to make each following robot maintain a desired pose to its leader, and the stability property of this controller is discussed using Lyapunov theory. By employing such controllers, the N-robot formation control problem can be decomposed into decentralized tracking problems between N-l followers and designated leaders. Additionally, graph theory is introduced to formalize general formation patterns in a simple but effective way and two types of switching between these formations are also proposed. Numerical simulations and physical robots experiments show the effectiveness of our approach.

Control and Coordination of Multiple Biomimetic Robotic Fish

Investigation in biomimetic robotic fish is a multidisciplinary area entirely integrating hydrodynamics-based control and robotic technology. In this brief, grounded on an optimized kinematic and dynamic model of robotic fish which synthesizes both the carangiform and anguilliform swimming modes, a free-swimming, multilink robotic fish and its motion control are designed. Employing top-down design approach, we propose a hierarchical architecture for an artificial multifish system which consists of five levels: task level, role level, behavior level, action level, and controller level, to formalize the processes from task decomposition, role assignments, and control performance. A vision-based, closed-loop experimental system for multiple robotic fish is finally constructed to verify the proposed architecture. The running experiments of fish versus man primarily show that much greater capabilities are exhibited when the fish try to cooperate with each other

Obstacle avoidance and path planning based on flow field for biomimetic robotic fish

This paper investigates the problem of obstacle avoidance and path planning for robotic fish. The swimming of the robot fish to avoid some obstacles is viewed as potential flow around the obstacles. Then the streamlines from the robot position to the target are chosen as the desired paths for the mobile robot to move to the destination. Since there are mature algorithms with high computational efficiency to establish flow field and figure out the streamlines based on fluid mechanics theory, our approach is practical for application. We conduct two example experiments to verify the effectiveness of the approach.

Flexible Formation Control for Obstacle Avoidance Based on Numerical Flow Field

This paper presents a novel approach to obstacle avoidance for a group of robots moving in formation. This idea is originally inspired by a phenomenon in hydrodynamics. In this approach, a virtual robot is introduced as a reference point (beacon) to determine a collision-free trajectory. Taking the virtual point as a basic point, the robot group establish a rigid body-like formation. Since the collision-freeness of the virtual robot does not guarantee all other robots avoiding obstacles, we employ a flexible formation control scheme in the framework of rigid body-like formation. Two kinds of transformation are introduced to help every robot negotiate obstacles. This approach gives a new principle to deal with obstacle avoidance in formation control for multi-robot system. Simulation results are presented to verify its effectiveness

Development of multiple robotic fish cooperation platform

This article presents the development of a multiple robotic fish cooperation platform, which is established by employing a group of radio-controlled, multi-link fish-like robots. This work is inspired by the observation from nature that the capability of one single fish is limited, as in order to survive the atrocious circumstances in the sea, fish often swim in schools. The analogical situations occur in the robotic fish case. In engineering applications, most missions are so complex that they must be accomplished by effective cooperation of multiple fish robots. The platform presented in this article, as a novel test bed for multiple robotic fish cooperation, can be applied to different types of complex tasks. More importantly, it provides a good platform to test and verify all kinds of algorithms and strategies for cooperation of multiple underwater mobile robots. We use two cooperative tasks as examples to heuristically demonstrate the performance of this platform.

Cooperative control of multiple robotic fish in a disk-pushing task

This paper is concerned with cooperative control of multiple robotic fish in order to achieve a disk-pushing task. Since the capability of a single fish robot is often limited, it might be incapable when carrying out many complex tasks in practice. In such a situation, multiple robotic fish are required to work cooperatively. We use a disk-pushing task as an example to illustrate how to organize multiple fish and plan motion for them. Corresponding experimental results are conducted to verify that through effective cooperation of the robotic fish can obtain high efficiency when achieving complex task

Formation Control of Multiple Biomimetic Robotic Fish

This paper presents a new method for formation control of multiple underwater fish-like robots. Considering both geometrical and mechanical constrains of the fish-like robots and based on the leader-following approach, a curvature coordinate is introduced to describe relative positions between different members within formations. Both the static and dynamic formations are concerned. We conduct simulations and physical experiments to verify effectiveness of the proposed algorithms

Collision-free motion planning for a biomimetic robotic fish based on numerical flow field

In this paper, we investigate motion planning for a biomimetic robotic fish which swims in underwater cluttered environment. For the collision-free motion planning problem, a widespread approach is to decouple it into two subproblems: paths generation and tracking control (or feedback regulation). However, consider the special propulsion mechanism and kinematic property of the robotic fish, it is difficult for it to track a predetermined path. To cope with this situation, a novel approach based on numerical flow field is proposed, which will generate a feasible velocity vector field instead of a determined path. Then the robotic fish will be inducted by a series of feasible velocity vectors to reach its destination. Experiments are conducted to verify the effectiveness of our approach

Platform for cooperation of multiple robotic fish — Robofish Water Polo

In this paper, we present the development of a multiple robotic fish cooperation system - robofish water polo, which is built on the basis of several multi-link biomimetic fish-like robots designed in our. The motivation of this work is that the capability of one single fish robot is often limited while there are many complex missions which should be accomplished by effective cooperation of multiple fish robots. Robofish water polo, as a novel platform of multiple robotic fish, can be applied to test and verify different algorithms and strategies for cooperation of multiple underwater robots. We have organized a two versus two competition to demonstrate the performance of this platform.