Decentralized MPC based Obstacle Avoidance for Multi-Robot Target Tracking Scenarios

In this work, we consider the problem of decentralized multi-robot target tracking and obstacle avoidance in dynamic environments. Each robot executes a local motion planning algorithm which is based on model predictive control (MPC). The planner is designed as a quadratic program, subject to constraints on robot dynamics and obstacle avoidance. Repulsive potential field functions are employed to avoid obstacles. The novelty of our approach lies in embedding these non-linear potential field functions as constraints within a convex optimization framework. Our method convexifies non-convex constraints and dependencies, by replacing them as pre-computed external input forces in robot dynamics. The proposed algorithm additionally incorporates different methods to avoid field local minima problems associated with using potential field functions in planning. The motion planner does not enforce predefined trajectories or any formation geometry on the robots and is a comprehensive solution for cooperative obstacle avoidance in the context of multi-robot target tracking. We perform simulation studies in different environmental scenarios to showcase the convergence and efficacy of the proposed algorithm. Video of simulation studies: \url{https://youtu.be/umkdm82Tt0M

Kompensasi Eksternal Disturbance Menggunakan Ctc Dengan Ndo Untuk Pengaturan Formasi Differential Drive Mobile Robot

Pengaturan formasi untuk mobile robot khususnya DDMR (Differential Drive Mobile Robot) telah banyak dikembangkan, hal ini dikarenakan pengaturan multi robot akan lebih efektif dibandingkan dengan satu robot untuk menyelesaikan suatu tugas tertentu. Metode untuk pembentukan formasi sekaligus tracking trayektori menjadi fokus pengembangan penelitian tentang pengaturan formasi. Dalam tesis ini digunakan pendekatan SBC (Separation Bearing Control) dan SSC (Separation Separation Control) untuk pembentukan formasi sekaligus tracking trayektori. Metode CTC juga digunakan untuk masing-masing agent. Metode tersebut digunakan untuk menyelesaikan permasalahan dinamika dari DDMR. Selain itu untuk menyelesaikan permasalahan disturbance pada robot, pada penelitian ini menggunakan metode NDO (Nonlinear Disturbance Observer). Hasil simulasi menunjukkan bahwa penggunaan CTC dengan NDO mampu mereduksi pengaruh disturbance pada robot sehingga formasi yang telah terbentuk dapat dipertahankan sesuai kriteria yang telah ditentukan. ===================================================================================================== Formation control for mobile robots especially DDMR (Differential Drive Mobile Robot) have been widely developed, this is because multi robot control will be more effective than that of a robot to accomplish a specific task. Methods for formation and tracking trajectory are the focus of research development on formation control. In this thesis the approach of SBC (Separation Bearing Control) and SSC (Separation Separation Control) are used to create formation and trajectory tracking. CTC method is also used for each agent. The method is used to solve the dynamic problem of DDMR. In addition, to solving the problem of disturbance in the robot, in this research use NDO (Nonlinear Disturbance Observer) method. Simulation results show that the use of CTC with NDO can reduce the effect of disturbance on the robot and the formation can be maintained according to the criteria

Fault-tolerant formation driving mechanism designed for heterogeneous MAVs-UGVs groups

A fault-tolerant method for stabilization and navigation of 3D heterogeneous formations is proposed in this paper. The presented Model Predictive Control (MPC) based approach enables to deploy compact formations of closely cooperating autonomous aerial and ground robots in surveillance scenarios without the necessity of a precise external localization. Instead, the proposed method relies on a top-view visual relative localization provided by the micro aerial vehicles flying above the ground robots and on a simple yet stable visual based navigation using images from an onboard monocular camera. The MPC based schema together with a fault detection and recovery mechanism provide a robust solution applicable in complex environments with static and dynamic obstacles. The core of the proposed leader-follower based formation driving method consists in a representation of the entire 3D formation as a convex hull projected along a desired path that has to be followed by the group. Such an approach provides non-collision solution and respects requirements of the direct visibility between the team members. The uninterrupted visibility is crucial for the employed top-view localization and therefore for the stabilization of the group. The proposed formation driving method and the fault recovery mechanisms are verified by simulations and hardware experiments presented in the paper

Formation control of nonholonomic mobile robots using implicit polynomials and elliptic Fourier descriptors

This paper presents a novel method for the formation control of a group of nonholonomic mobile robots using implicit and parametric descriptions of the desired formation shape. The formation control strategy employs implicit polynomial (IP) representations to generate potential fields for achieving the desired formation and the elliptical Fourier descriptors (EFD) to maintain the formation once achieved. Coordination of the robots is modeled by linear springs between each robot and its two nearest neighbors. Advantages of this new method are increased flexibility in the formation shape, scalability to different swarm sizes and easy implementation. The shape formation control is first developed for point particle robots and then extended to nonholonomic mobile robots. Several simulations with robot groups of different sizes are presented to validate our proposed approach

A survey on fractional order control techniques for unmanned aerial and ground vehicles

In recent years, numerous applications of science and engineering for modeling and control of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) systems based on fractional calculus have been realized. The extra fractional order derivative terms allow to optimizing the performance of the systems. The review presented in this paper focuses on the control problems of the UAVs and UGVs that have been addressed by the fractional order techniques over the last decade