Leader-Follower Formation Control of Wheeled Mobile Robots without Attitude Measurements

Abstract

The problem of leader-follower formation of a platoon of differential-drive wheeled mobile robots without using attitude measurements is addressed in this paper. Contrary to the position-distance approaches existing in the literature, the formation and collision avoidance is achieved by introducing a state-dependent delay in the desired trajectory. The delay is obtained as the output of a dynamical system and its magnitude will decrease/increase depending on the distance between the robots. To guarantee trajectory tracking and to overcome the lack of orientation measurements, an output feedback control and attitude observer are proposed based on the kinematic model of the robots. The attitude observer is designed directly on the special orthogonal group SO(2) and it can be used in open-loop schemes. The proposed control-observer scheme ensures asymptotic convergence of the tracking and observer errors. Finally, experimental results are presented to show the performance of the proposed approach.

Control of mobile robot formations using A-star algorithm and artificial potential fields

“…The 𝜌̇ on the left side of equation ( 5) represents the time derivative of the Euclidean distance (𝜌), and the addends on the right side are the partial derivatives of 𝜌 with respect to 𝑥 , 𝑦 , and 𝜃 , respectively. In equations ( 6), (7), and ( 8), the derivatives of the addends present on the right side of equation ( 5) are demonstrated.…”

“…where 𝑥 𝑅 , 𝑦 𝑅 represent the robot position coordinates on the 𝑋 𝐼 and 𝑌 𝐼 axes and 𝑥 𝐺 , 𝑦 𝐺 are the goal position coordinates on the 𝑋 𝐼 and 𝑌 𝐼 axes of the inertial frame. Substituting the results obtained in equations ( 6), (7), and (8) in equation ( 5), the equation ( 9) is derived.…”

“…Several advantages are pointed out with the implementation of robotic formations, such as better precision, increased efficiency and robustness against external agents [2]. The methods of controlling the formation of mobile robots can be divided into three classes: behavioral approach, virtual structure approach, and leader-follower approach [6] [7]. In the leader-follower approach, one of the robots plays the role of leader and the rest are followers.…”

Differentially-Driven Robots Moving in Formation—Leader–Follower Approach

“…Thanks to these properties the controller has very strong practical features. Other propositions concerning some practical aspects of mobile robots formation control can be found in references [17,18]. In reference [17], vision-based control with on-board camera and absence of the feature depth information is presented.…”

“…In reference [17], vision-based control with on-board camera and absence of the feature depth information is presented. In the paper [18] formation control with lack of the orientation measurements is described. Instead of attitude measurements, the Authors used designed observer.…”