A Switched Approach to Image-Based Stabilization for Nonholonomic Mobile Robots with Field-of-View Constraints

This paper presents a switched visual servoing strategy for maneuvering the nonholonomic mobile robot to the desired configuration while keeping the tracked image points in the vision of the camera. Firstly, a pure backward motion and a pure rotational motion are applied to the mobile robot in succession. Thus, the principle point and the scaled focal length in x direction of the camera are identified through the visual feedback from a fixed onboard camera. Secondly, the identified parameters are used to build the system model in polar-coordinate representation. Then an adaptive non-smooth controller is designed to maneuver the mobile robot to the desired configuration under the nonholonomic constraint. And a switched strategy which consists of two image-based controllers is utilized for keeping the features in the field-of-view. Simulation results are presented to validate the effectiveness of the proposed approach.

Uji Presisi dari Nonholonomic Mobile Robot pada Rancang Bangun Sistem Navigasi

Navigasi menjadi bagian yang penting bagi kendaraan. Global positioning system (GPS) merupakan sistem navigasi yang paling banyak digunakan pada kendaraan. Namun dengan akurasi 5-10 meter membuat GPS tidak bisa diaplikasikan dalam bagian sistem kendali pada kendaraan. Penambahan sensor inertia measurement unit (IMU) diharapkan mampu menambahkan akurasi pada Gerakan kendaraan. Kendaran yang digunakan adalah robot beroda dengan sistem nonholonomic. Pada robot ini dipasang Sensor IMU, GPS dan kontroler supaya robot tersebut bisa berputar lalu melaju secara lurus dengan kordinat yang sudah ditentukan. Hasil pengujian didapatkan robot memiliki respon time sebesar 4.1 detik tanpa kontroler dan 2.1 detik dengan kontroler. Akurasi sudut dari 5 menjadi 2 .

Trajectory Tracking with Input Constraint based on LMI Approach of a Nonholonomic Mobile Robot

Nonholonomic Mobile Robot (NMR) is a mode of transportation that is widely used in industry. To achieve flexibility in carrying out its duties, an adequate control system is needed in transportation arrangements so that it is used as an object of research. The problem that is taken in this study is about tracking control for several reference trajectories with input constraint.To solve this problem two controllers were designed, kinematics controller and dynamics controller. Kinematics controller is designed so that the additional speed converges to the desired speed by adjusting the gain value , , and . Dynamic controller is designed using performance to overcome the input constraint and the Lyapunoc inequality is soleved by Linear Matric Inequalities (LMI) so the gain state-feedback can be obtained. Simulation results show that the designed controller is capable of tracking according to the reference trajectory with input constraint given.