Multiple Nonholonomic Agents Research Articles

Bearing-Constrained Formation Tracking Control of Nonholonomic Agents Without Inter-Agent Communication

This letter presents two bearing-constrained formation tracking control protocols for multiple nonholonomic agents based respectively on the bearing vectors and displacements between the agents. The desired formation pattern of the system is specified by the desired inter-agent bearing vectors. In the proposed control schemes, there are two or more leaders moving with the same constant velocity; the other follower agents do not have the information of the leaders’ velocity nor communicate variables with their neighbors. Under both the proposed control laws, the system achieves the moving target formation asymptotically. Simulation results are provided to support the theoretical development.

Neural-Adaptive Finite-Time Formation Tracking Control of Multiple Nonholonomic Agents With a Time-Varying Target

This paper investigates the leader-following formation tracking problem (FTP) for multiple nonholonomic agent systems (MNASs) in the presence of external disturbances and parametric uncertainties, where both the kinematics and dynamics of the agents are taken into consideration. A novel finite-time distributed controller-estimator algorithm (DCEA) is designed to handle such a challenging problem. Based on Lyapunov stability method, the sufficient conditions for finite-time stability of the closed-loop system are derived. Finally, the simulation results are presented to demonstrate the effectiveness and the robustness of the proposed DCEA.

Fixed‐time stabilisation and consensus of non‐holonomic systems

This paper focuses on the design of fixed-time consensus for multiple unicycle-type mobile agents. A distributed switched strategy, based on local information, is proposed to solve the leader-follower consensus problem for multiple nonholonomic agents in chained form. The switching times and the prescribed convergence time are explicitly given regardless of the initial conditions. Simulation results highlight the efficiency of the proposed method.

Finite time consensus problem for multiple non-holonomic agents with communication delay

In this paper, the problem of finite time consensus is discussed for multiple non-holonomic mobile agents with communication delay. The objective is to design distributed control laws such that multiple non-holonomic mobile agents can be all in agreement within finite time. We propose a novel switching control strategy with the help of Lyapunov-based method and graph theory.

Decentralized Leader-Follower Flocking of Multiple Non-Holonomic Agents

In this paper, we study the cohesive flocking problem of multiple non-holonomic agents governed by extended second-order unicycle dynamics, such as robotic fish. Consider the system with only one leader. Combining the consensus algorithm and attraction/repulsion functions, a distributed flocking algorithm is presented for multiple robotic fish to complete the cohesive flocking task. According to LaSalle-Krasovskii invariance principle, the proposed algorithm enables followers to asymptotically track the leader's velocity and approach the equilibrium distances with their neighbors, provided that the initial interaction network among the followers is an undirected connected graph, and there exists at least one follower having a leader neighbor at the initial time. During the evolutionary process, the connectivity of the communication network can be preserved due to the effect of the potential function. Finally, a simulation example is given to verify the proposed theoretical analysis.

Distributed observer-based cooperative control of multiple nonholonomic mobile agents

In this article, cooperative output feedback control of a group of nonholonomic mobile agents is considered. Distributed observer-based cooperative control laws are proposed with the aid of Lyapunov techniques and results from graph theory. Robustness of the stability of the closed-loop systems with the proposed control laws is considered. The effectiveness of the proposed controllers is verified by simulation results.

Formation control for nonholonomic agents using passivity techniques

This paper studies the problem of the formation control for the multiple nonholonomic agents on a plane. A dynamic feedback linearization method is used to transform the dynamical model of each agent into two third-order integrator chains. A decentralized formation control law with the inter-agent damping injection is derived. The asymptotical stability of the overall system is proven using the Lyapunov method. The simulation of the formation maneuver of a planar vehicle shows the effectiveness of the proposed method.

On the Rendezvous Problem for Multiple Nonholonomic Agents

In this note, a decentralized feedback control strategy that drives a system of multiple nonholonomic unicycles to a rendezvous point in terms of both position and orientation is introduced. The proposed nonholonomic control law is discontinuous and time-invariant and using tools from nonsmooth Lyapunov theory and graph theory the stability of the overall system is examined. Similarly to the linear case, the convergence of the multi-agent system relies on the connectivity of the communication graph that represents the inter-agent communication topology. The control law is first defined in order to guarantee connectivity maintenance for an initially connected communication graph. Moreover, the cases of static and dynamic communication topologies are treated as corollaries of the proposed framework

A feedback control scheme for multiple independent dynamic non-point agents

The Decentralized Navigation Functions' (DNF) based methodology, established in our previous work (D.V. Dimarogonas, M.M. Zavlanos, S.G. Loizou and K.J. Kyriakopoulos, “Decentralized motion control of multiple holonomic agents under input constraints”, in 42nd IEEE Conf. Deci. Cont., 2003, pp. 3390–3395 and S.G. Loizou, D.V. Dimarogonas and K.J. Kyriakopoulos, “Decentralized feedback stabilization of multiple nonholonomic agents”, in 2004 IEEE Int. Conf. on Robotics and Autom., 2004, pp. 3012–3017) on multi-agent systems with kinematic models of motion, is extended to the case where dynamic models of motion for both holonomic and nonholonomic agents must be treated. The proposed control scheme guarantees collision avoidance and global convergence of the multi-agent team to the desired goal configuration. The volume of each agent is taken into account and non-point models are considered. The satisfaction of the imposed system specifications under the proposed control scheme are verified and depicted through non-trivial computer simulations.

Centralized feedback stabilization of multiple nonholonomic agents under input constraints

In this paper we use the centralized multirobot navigation function methodology established by the authors, augmented with an enhanced dipolar navigation field suitable for non-holonomic vehicls. A properly designed discontinuous feedback control law is applied to steer the nonholonomic vehicles. The esulting high frequency switching behavior, known as chattering, which is inherent in discontinuous controllers, is tackled with an appropriately designed discontinuous backstepping controller, which effectively reduces chattering. The vehicles are assumed to have limitations on their maximum achievable velocities. Those issues are taken into account in the control law design. The resulting closed form control scheme provides robust navigation withguaranteed collision avoidance and global convergence properties, as well as fast feedback, rendering the methodology particularly suitable for real time implementation, on systems with limited actuation capabilities. Collision avoidance and global convergence properties are verified through non - trivial computer simulations.