Krishna Raghuwaiya

Cooperative Control of Multi-robot Systems with a Low-Degree Formation

The utilization of team of robots working in a cooperative manner has huge benefits in moving large payloads. To perform such tasks, a multi robot structure or formation is necessary to coordinate the motions of the robots in a well planned manner. In this paper, the formation control problem of multi car-like mobile robots have been studied. The purpose is to get a swarm of mobile robots in a certain formation pattern to track a desired trajectory to accomplish a set objective. A set of artificial potential field functions is proposed using the Direct Method of Lyapunov for avoiding inter-robot, inter-formation and obstacle collisions and attraction to their designated targets. The effectiveness of the proposed nonlinear acceleration control laws is demonstrated through computer simulation results which prove the efficiency of our control technique and also demonstrates scalability for a large group of robots.

Path Following of Autonomous Agents Under the Effect of Noise

In this paper, we adopt the architecture of the Lyapunov-based Control Scheme (LbCS) and integrate a leader-follower approach to propose a collision-free path following strategy of a group of mobile car-like robots. A robot is assigned the responsibility of a leader, while the follower robots position themselves relative to the leader so that the path of the leader robot is followed with arbitrary desired clearance by the follower robot, avoiding any inter-robot collision while navigating in a terrain with obstacles under the influence of noise. A set of artificial potential field functions is proposed using the control scheme for the avoidance of obstacles and attraction to their designated targets. The effectiveness of the proposed nonlinear acceleration control laws is demonstrated through computer simulations which prove the efficiency of the control technique and also demonstrates its scalability for larger groups.

Leader-Follower Based Locally Rigid Formation Control

This paper addresses motion control of a cooperative intelligent transport system (C-ITS) of nonholonomic mobile robots navigating a dynamic environment while maintaining a locally rigid formation. We consider the design of acceleration-based control inputs that govern the motion of cooperative intelligent transport system (C-ITS) using the artificial potential fields method for the avoidance of obstacles and attraction to designated targets. The control scheme utilizes a new leader-follower strategy using Cartesian coordinates to accomplish a collision-free locally rigid formation of an autonomous and intelligent transportation system. The concepts of virtual parking bays and minimum distance technique (MDT) are utilized to attain prescribed orientations of the formation at the final destination. The robustness of the control scheme is established by considering the effect noise on the formation, while the effectiveness of the proposed nonlinear control laws is demonstrated through computer simulations.

Formation Splitting and Merging

This paper presents an approach to swarm split and rejoin maneuvers of a system of multi-robots formations. A post split formation is split into low-degree sub-swarms when the swarm encounters an obstacle. The sub-swarms reestablish links with other sub-swarms and converge into its pre-split formation after avoiding collisions with the obstacles. The leader-follower control strategy is used for maintaining formation shape in the sub-swarms. A set of artificial potential field functions is proposed for avoiding inter-robot, inter-formation and obstacle collisions and attraction to their designated targets. The Direct Method of Lyapunov is then used to establish stability of the given system. The effectiveness of the proposed nonlinear acceleration control laws is demonstrated through a computer simulation.

Swarming Intelligence of 1-Trailer Systems

In this paper, we propose a new solution to motion planning and control problem for a flock of 1-trailer systems. A set of artificial potential field functions is proposed for the flock of 1-trailer robots via the Lyapunov-based control scheme for the avoidance of swarm of boids and attraction to their designated targets. The dynamic environment for the first time includes a swarm of boids, which is governed separately by a system of ODE’s. The swarm exhibits collective emergent behaviors in the vicinity of the workspace while the flock of 1-trailer systems safely maneuver from their initial configuration to designated targets. The effectiveness of the control laws is demonstrated via computer simulations. The novelty of the paper lies in the simplicity of the controllers and the ease in the treatment of the dynamic environment.