This study aims to achieve the trajectory-tracking of an autonomous differential drive mobile robot (ADDMR) in the presence of friction torques using the proposed Fuzzy Sliding-Mode Control (FSMC). First, the complete model of the ADDMR is established including kinematic, dynamic and actuator models. Then, the desired trajectory is planned and generated via Bézier curve combined with cubic time mapping. The localization of the ADDMR is performed using the Monte Carlo Localization (MCL) technique and LiDAR point cloud data. Subsequently, the proposed FSMC utilizes nonlinear sliding surfaces inferred based on fuzzy logic to asymptotically attain the pose convergence. To investigate the feasibility and robustness of the proposed FSMC, simulations and experiments are conducted under different operation conditions. The results show that the proposed FSMC using LiDAR data in the feedback leads to excellent control performance even in the presence of friction torques. It was also shown through simulations and experiments that the established ADDMR model fits the actual ADDMR model very well.

Nowadays, an omnidirectional conveyor system has been introduced as a new means of package transportation. The aim of this study is to achieve trajectory-tracking and collision avoidance of multiple packages which has not been done before on an omnidirectional conveyor platform. Despite the kinematic similarity to omnidirectional mobile robots which have built-in sensors to measure velocities and accelerations, this system only measures the position of the transported package via external sensors which makes it a unique and intriguing area of research. To tackle this challenge, this study employs the proposed Fuzzy Sliding-mode Tracking Control (FSTC) and Fuzzy Inter-package Collision Avoidance (FICA) schemes. The FSTC has been enhanced with fuzzy sliding surfaces that take tracking errors as control inputs and linear forces as control outputs. Additionally, using a fuzzified package distance and collision angle as inputs, the inference engine of FICA is designed to generate the deflection angle and force gain as outputs. Additionally, the conveyor platform is modeled and built by a multiple modular omnidirectional wheel system including the conveyor and actuator dynamics. To determine its desired motion trajectory, a planned 4th-order Bèzier curve is utilized. Then, to assess the effectiveness and robustness of the proposed methods, simulations are conducted under diverse conditions. The results indicate that the package position converges within a finite time frame, highlighting the superior trajectory-tracking capabilities of FSTC in spite of any disturbances injected into position feedback signals. Meanwhile, the proposed FICA has demonstrated its effectiveness by enabling the package to navigate through the omnidirectional conveyor platform while avoiding both stationary and moving obstacles.