scholarly journals Evaluation of the Path-Tracking Accuracy of a Three-Wheeled Omnidirectional Mobile Robot Designed as a Personal Assistant

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7216
Author(s):  
Jordi Palacín ◽  
Elena Rubies ◽  
Eduard Clotet ◽  
David Martínez
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Tracking System ◽  
Empirical Evaluation ◽  
Ground Truth ◽  
Path Tracking ◽  
Absolute Maximum ◽  
Tracking Accuracy ◽  
Maximum Displacement ◽  
Omnidirectional Mobile Robot

This paper presents the empirical evaluation of the path-tracking accuracy of a three-wheeled omnidirectional mobile robot that is able to move in any direction while simultaneously changing its orientation. The mobile robot assessed in this paper includes a precise onboard LIDAR for obstacle avoidance, self-location and map creation, path-planning and path-tracking. This mobile robot has been used to develop several assistive services, but the accuracy of its path-tracking system has not been specifically evaluated until now. To this end, this paper describes the kinematics and path-planning procedure implemented in the mobile robot and empirically evaluates the accuracy of its path-tracking system that corrects the trajectory. In this paper, the information gathered by the LIDAR is registered to obtain the ground truth trajectory of the mobile robot in order to estimate the path-tracking accuracy of each experiment conducted. Circular and eight-shaped trajectories were assessed with different translational velocities. In general, the accuracy obtained in circular trajectories is within a short range, but the accuracy obtained in eight-shaped trajectories worsens as the velocity increases. In the case of the mobile robot moving at its nominal translational velocity, 0.3 m/s, the root mean square (RMS) displacement error was 0.032 m for the circular trajectory and 0.039 m for the eight-shaped trajectory; the absolute maximum displacement errors were 0.077 m and 0.088 m, with RMS errors in the angular orientation of 6.27° and 7.76°, respectively. Moreover, the external visual perception generated by these error levels is that the trajectory of the mobile robot is smooth, with a constant velocity and without perceiving trajectory corrections.

scholarly journals Mixed Reality Enhanced User Interactive Path Planning for Omnidirectional Mobile Robot

2020 ◽  
Vol 10 (3) ◽  
pp. 1135 ◽  
Author(s):  
Mulun Wu ◽  
Shi-Lu Dai ◽  
Chenguang Yang
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Mixed Reality ◽  
Avoidance Performance ◽  
Motion Path ◽  
The Real ◽  
Virtual Objects ◽  
Omnidirectional Mobile Robot ◽  
Real Environment ◽  
Control Command

This paper proposes a novel control system for the path planning of an omnidirectional mobile robot based on mixed reality. Most research on mobile robots is carried out in a completely real environment or a completely virtual environment. However, a real environment containing virtual objects has important actual applications. The proposed system can control the movement of the mobile robot in the real environment, as well as the interaction between the mobile robot’s motion and virtual objects which can be added to a real environment. First, an interactive interface is presented in the mixed reality device HoloLens. The interface can display the map, path, control command, and other information related to the mobile robot, and it can add virtual objects to the real map to realize a real-time interaction between the mobile robot and the virtual objects. Then, the original path planning algorithm, vector field histogram* (VFH*), is modified in the aspects of the threshold, candidate direction selection, and cost function, to make it more suitable for the scene with virtual objects, reduce the number of calculations required, and improve the security. Experimental results demonstrated that this proposed method can generate the motion path of the mobile robot according to the specific requirements of the operator, and achieve a good obstacle avoidance performance.

Assessment of the Accuracy of Optical Shape Sensing for Needle Tracking Interventions

2017 ◽  
Vol 11 (3) ◽  
Author(s):  
Koushik Kanti Mandal ◽  
Francois Parent ◽  
Raman Kashyap ◽  
Sylvain Martel ◽  
Samuel Kadoury
Keyword(s):  
Optical Fibers ◽  
Liver Tumors ◽  
Tracking System ◽  
Ground Truth ◽  
Guidance System ◽  
Tracking Accuracy ◽  
Percutaneous Procedures ◽  
Fbg Sensors ◽  
Mri Guided ◽  
Similar Accuracy

Accurate needle guidance is essential for a number of magnetic resonance imaging (MRI)-guided percutaneous procedures, such as radiofrequency ablation (RFA) of metastatic liver tumors. A promising technology to obtain real-time tracking of the shape and tip of a needle is by using high-frequency (up to 20 kHz) fiber Bragg grating (FBG) sensors embedded in optical fibers, which are insensitive to external magnetic fields. We fabricated an MRI-compatible needle designed for percutaneous procedures with a series of FBG sensors which would be tracked in an image-guidance system, allowing to display the needle shape within a navigation image. A series of phantom experiments demonstrated needle tip tracking errors of 1.05 ± 0.08 mm for a needle deflection up to 16.82 mm on a ground-truth model and showed nearly similar accuracy to electromagnetic (EM) tracking (i.e., 0.89 ± 0.09 mm). We demonstrated feasibility of the FBG-based tracking system for MRI-guided interventions with differences under 1 mm between tracking systems. This study establishes the needle tracking accuracy of FBG needle tracking for image-guided procedures.

A gait-assistive mobile robot based on a body weight support and autonomous path tracking system

2011 ◽  
Vol 226 (3) ◽  
pp. 828-841 ◽  
Author(s):  
S-N Yu ◽  
J-H Jang ◽  
D-H Kim ◽  
J-Y Lee ◽  
C-S Han
Keyword(s):  
Body Weight ◽  
Mobile Robot ◽  
Obstacle Avoidance ◽  
Tracking System ◽  
The Elderly ◽  
Path Tracking ◽  
Body Weight Support ◽  
Operation Condition ◽  
Rehabilitation Centre ◽  
Weight Support

With the rising numbers of elderly and disabled people, the demand for welfare services using a robotic system and not involving human effort is likewise increasing. This study deals with a mobile robot system combined with a body weight support (BWS) system for gait rehabilitation. The BWS system was designed via the kinematic analysis of the robot's body-lifting characteristics and of the walking guide system that controls the total rehabilitation system integrated in the mobile robot. This mobile platform is operated by utilizing the autonomous guided vehicle driving algorithm. Especially, the method that integrates geometric path tracking and obstacle avoidance for a non-holonomic mobile robot was applied so that the system can be operated in an area where the elderly users are expected to be situated, such as in a public hospital or a rehabilitation centre. The mobile robot follows the path by moving through the turning radius supplied by the pure-pursuit method, one of the existing geometric path-tracking methods. The effectiveness of the proposed method was verified through real experiments that were conducted for path tracking with static and dynamic obstacle avoidance. Finally, through electromyography signal measurement of the subject, the performance of the proposed system in a real operation condition was evaluated.

scholarly journals Autonomous navigation of a magnetic colonoscope using force sensing and a heuristic search algorithm

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hao-En Huang ◽  
Sheng-Yang Yen ◽  
Chia-Feng Chu ◽  
Fat-Moon Suk ◽  
Gi-Shih Lien ◽  
...  
Keyword(s):  
Path Planning ◽  
Real Time ◽  
Autonomous Navigation ◽  
Permanent Magnets ◽  
Search Algorithm ◽  
Tracking System ◽  
Training Model ◽  
Force Sensing ◽  
Tracking Accuracy ◽  
Surgical Safety

AbstractThis paper presents an autonomous navigation system for cost-effective magnetic-assisted colonoscopy, employing force-based sensors, an actuator, a proportional–integrator controller and a real-time heuristic searching method. The force sensing system uses load cells installed between the robotic arm and external permanent magnets to derive attractive force data as the basis for real-time surgical safety monitoring and tracking information to navigate the disposable magnetic colonoscope. The average tracking accuracy on magnetic field navigator (MFN) platform in x-axis and y-axis are 1.14 ± 0.59 mm and 1.61 ± 0.45 mm, respectively, presented in mean error ± standard deviation. The average detectable radius of the tracking system is 15 cm. Three simulations of path planning algorithms are presented and the learning real-time A* (LRTA*) algorithm with our proposed directional heuristic evaluation design has the best performance. It takes 75 steps to complete the traveling in unknown synthetic colon map. By integrating the force-based sensing technology and LRTA* path planning algorithm, the average time required to complete autonomous navigation of a highly realistic colonoscopy training model on the MFN platform is 15 min 38 s and the intubation rate is 83.33%. All autonomous navigation experiments are completed without intervention by the operator.

Path Tracking Method for Traveling-Wave-Type Omnidirectional Mobile Robot (TORoIII)

2012 ◽  
Vol 24 (2) ◽  
pp. 340-346 ◽  
Author(s):  
Teruyoshi Ogawa ◽  
◽  
Taro Nakamura
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Traveling Wave ◽  
Potential Method ◽  
Path Tracking ◽  
Planning Method ◽  
Stable Operation ◽  
Wave Type ◽  
Tracking Method ◽  
Path Tracking Method

An omnidirectional movement mechanism is needed that can move a robot in a narrow complicated passage. However, existing mechanisms cannot achieve stable operations. We noted that a snail uses traveling waves and can achieve a stable operation because of a large landing area. We therefore developed a traveling-wave-type mobile robot (TORoIII) using a snail’s locomotive mechanism. However, the directions of the robot were restricted by the number of units, i.e., the directions corresponded to the number of units. In addition, to use this robot as an autonomous robot, self-localization method and path planning method are required. At present, these methods for this robot have not been proposed. In this study, we propose a new perfectly omnidirectional locomotion strategy for TORoIII. In addition, we propose odometry based on kinematics and path planning method based on potential method. Furthermore, we propose online path tracking method using the odometry. We experimentally confirmed the utility of these proposed methods.

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