Omnidirectional Wheels Research Articles

Investigation of Dynamic Characteristics of Holonomic Robot with Mecanum wheels Based on 3D Parametric Simulation Model

The paper analyzes dynamic characteristics of a four-wheeled mobile robot driven by omnidirectional mecanum wheels. To obtain information about dynamic characteristics of the robot, a computer model was developed in the MATLAB Simulink block modeling software environment. The constructed simulation model allowed to research the behavior of a holonomic mobile object with mecanum wheels in start-braking modes, based not only on its mathematical model, but also ta-king into account the weight and size parameters of the robot, introduced into the model through the integration of a three-dimensional digital prototype of the object. The investigation of the omnidirectional robot dynamics was considered within modeling the acceleration, uniform movement and deceleration of an object on a plane along a rectilinear trajectory. As a result, the dependences of kinematic, dynamic and mechanical characteristics were obtained, such as the dependence of angular velocity and torque of each wheel on time; the dependence of linear velocity of the robot's center of mass on time; the dependence of distance traveled by the robot on time; positioning errors while processing a given movement; spatial visualization of speed fluctuations. With the help of Mechanical Explorer tool, using a digital clone of the robot integrated into the model, an animation of the object’s movement along the trajectory was obtained. This approach, based on the integration of mathematical block and three-dimensional parametric models of the object with the possibility of visualization and animation of the results, allows to most fully investigate the dynamics and kinematics of nonlinear mechatronic systems. The obtained information of positioning errors and speed fluctuations in three coordinates allowed to conclude that there were random fluctuations during the robot’s movement, but their presence did not have a noticeable effect on the accuracy of the specified trajectory.

Kinematic modeling and control of orthogonal omnidirectional wheeled two-dimensional conveyor platform

This paper proposes an orthogonal omnidirectional wheeled two-dimensional conveyor platform and the inverse kinematic equations based on the cell model and the omnidirectional wheel model are derived, respectively. The two models use the way of the circumcircle of the cargo box and the dot product method to obtain the cell or omnidirectional wheel directly contacted under the cargo box, respectively. This paper uses YOLOV8_OBB and Strong SORT target tracking algorithms to assign tracking IDs to the cargo box and output the box position information. A feedback mechanism for faulty omnidirectional wheels or faulty cells is proposed, where the faulty area is classified as impassable during path planning and the A* path planning algorithm is used for path planning to avoid the faulty area. A visual feedback-based path tracking is adopted to enable timely correction when the cargo box deviates from the established path. The experimental results show that the omnidirectional wheel-based model improves the path-tracking accuracy by 44.52% and reduces the average power consumption by 2.6 times compared to the cell-based model.

Research on a Novel Citrus Reticulata ‘Chachi’ Orientation Adjustment Mechanism (COAM) and Machine Vision Guidance Control

The initial processing of Citrus Reticulata ‘Chachi’ involves peeling as a crucial step. Currently, there is some semi-automatic peeling equipment available. However, due to the requirement of adjusting the orientation of Citrus Reticulata ‘Chachi’ to ensure the stem (or navel) is facing upwards before peeling and because the peeling process must retain the stem as a marker for fresh fruit picking, the loading of Citrus Reticulata ‘Chachi’ for peeling still solely relies on manual operation, resulting in low efficiency and poor standardization. With the rapid growth of the pericarp of the Citrus Reticulata ‘Chachi’ industry, semi-automatic processing equipment is no longer able to meet production demands. The loading issue before peeling Citrus Reticulata ‘Chachi’ is a complex hand–eye coordination problem. In response to this issue, this paper proposes a novel Citrus Reticulata ‘Chachi’ orientation adjustment mechanism (COAM). This mechanism utilizes frictional force to adjust the orientation of Citrus Reticulata ‘Chachi’. First, the conceptual design and kinematic modelling analysis of the mechanism were conducted. Next, the omnidirectional friction-driven wheels were optimized in design. Subsequently, a prototype was manufactured and assembled to conduct validation tests on its open-loop motion performance. Finally, a visual feedback-guided algorithm was introduced to complement the kinematic model, enabling the automatic and rapid adjustment of Citrus Reticulata ‘Chachi’ orientation. The experimental results indicate that the COAM designed in this study can effectively and rapidly adjust the orientation of Citrus Reticulata ‘Chachi’ fruits of different sizes and shapes. It demonstrates strong adaptability, and under visual feedback guidance, the orientation adjustment error is less than 10% of the fruit’s diameter. This meets the requirements for automated production in the initial processing of Citrus Reticulata ‘Chachi’. The research presented in this paper also provides new insights for the orientation adjustment and loading of similar spherical fruits.

Design and Implementation of a Land-Air Omnidirectional Mobile Robot

This paper proposes a new type of omnidirectional mobile robot for land and air, which has three motion modes, combines the motion characteristics of land motion and air flight, has the ability to climb walls, and can be actively deformed to adapt to the working conditions according to the current working environment. The robot incorporates an innovative “rotor blade–single row omnidirectional wheel” composite structure, which is mainly characterized by a single row of continuous switching wheels covering the outside of each rotor blade, and does not need to provide additional power when moving on the ground and walls, relying on the driving force generated by the rotor blades to drive the continuous switching wheels driven by the rotor blades. This structure can effectively combine the land movement mode, wall crawling mode, and air flight mode, which reduces the energy consumption of the robot without increasing the weight, and we design a deformation device that can realize the transformation of the three modes into each other. This paper mainly focuses on the design of the robot structure and the analysis of the movement method, and the land omnidirectional movement experiments, wall crawling experiments, and air flight experiments were, respectively, carried out, and the results show that the proposed land and air omnidirectional mobile robot has the ability to adapt to the movement of each scene, and improves the upper limit of the robot’s operation.

A triangle decomposition method for the mobility control of mecanum wheel-based robots

Mobile robots are used in a variety of applications including research, education, healthcare, customer service, security and so on. Based upon the application, the robots employ different locomotion systems for their mobility. When it comes to rolling locomotion, the wheels used to provide mobility to robots can be categorized as: tracks, omnidirectional wheels, and unidirectional wheels with a steering system. The ability of omnidirectional wheels to drive machines in small spaces makes them interesting to use. Among the types of omnidirectional wheels, mecanum wheels are widely used due to their inherent benefits. With the right control strategy, robots equipped with mecanum wheels can move freely, in all possible directions. In this study, a triangle decomposition approach is employed for controlling omnidirectional mecanum wheel-based robots. The method consists of breaking down any path into a set of linear motions that can be horizontal, vertical, or oblique. Furthermore, the oblique paths are divided into smaller segments that can be resolved into a horizontal and vertical component in a right-angle triangle. The suggested control method is tested and proved on a simple scenario using Webots simulation software.

Mathematical Model of Movement of a Mobile Robot with Omnidirectional Wheels

The article discusses the issue of controlling a four-wheeled mobile robot with omnidirectional wheelsof the mecanum type. An analysis of the rotational motion of the omnidirectional mecanum wheel was carriedout, based on its kinematics. For a specific robot with certain overall parameters, a graph of changes in the radiusof the mecanum wheel depending on the angle of its rotation was constructed. Kinematic and dynamic modelsof a mobile four-wheeled robot have been compiled, taking into account its geometric characteristics. The presented expressions are a mathematical description of the behavior of a mobile robot in statics and dynamics. Basedon the obtained models, the principles of operation of the motion control system for a four-wheeled mobile roboton omnidirectional wheels of the mecanum type are formed.

Study of the Dynamics of Automated Guided Vehicle Using Mecanum Omnidirectional Wheel

The paper presents the result of the dynamics simulation of automated guided vehicles (AGVs) using four Mecanum omnidirectional wheels when the tilt angle of each wheel’s roller is changed. Mecanum omnidirectional wheels have the ability to work flexibly, but operators are generally concerned about the vehicle’s efficiency issues. The performance of the wheel significantly influences the extensive application range of the vehicle. The method of modeling automated guided vehicles and Mecanum wheels is applied in order to build its kinematic model and dynamic model with omnidirectional wheels when the roller’s angle of incline is changed. Based on Lagrange’s equation of type II, the equation of motion of the vehicle is established in accordance with the actual situation that the vehicle is being applied. The rolling friction coefficient and the adhesive coefficient of Mecanum wheels were measured experimentally on different road surfaces, including concrete, wood, brick, and stone. The study's findings successfully address efficiency challenges in vehicles using omnidirectional wheels when varying the incline angle of each roller and applying fuzzy logic for trajectory control in autonomous vehicles.

Geometry and Kinematics of the Mecanum Wheel on a Plane and a Sphere

This article is devoted to a study of the geometry and kinematics of the Mecanum wheels, also known as Ilon wheels or the Swedish wheels. The Mecanum wheels are one of the types of omnidirectional wheels. This property is provided by peripheral rollers whose axes are deviated from the wheel one by 45 degrees. A unified approach to studying the geometry and kinematics of the Mecanum wheels on a plane and on the internal or external surface of a sphere is proposed. Kinematic relations for velocities at the contact point of the wheel and the supporting surface, and angular velocities of the roller relative to the supporting surface are derived. They are necessary to describe the dynamics of the Mecanum systems taking into account forces and moments of contact friction in the presence of slipping. From the continuous contact condition, relations determining the geometry of the wheel rollers on a plane and on the internal or external surface of a sphere are obtained. The geometric relations for the Mecanum wheel rollers could help to adjust the existing shape of the Mecanum wheel rollers of spherical robots and ballbots to improve the conditions of contact between the rollers and the spherical surface. An analytical study of the roller geometry was carried out, and equations of their generatrices were derived. Under the no-slipping condition, expressions for rotational velocities of the wheel and the contacting roller are obtained. They are necessary for analyzing the motion of systems within the framework of nonholonomic models, solving problems of controlling Mecanum systems and improving its accuracy. Using the example of a spherical robot with an internal three-wheeled Mecanum platform, the influence of the rollers on the robot movement was studied at the kinematic level. It has been established that the accuracy of the robot movement is influenced not only by the geometric parameters of the wheels and the number of rollers, but also by the relationship between the components of the platform center velocity and its angular velocity. Results of the numerical simulation of the motion of the spherical robot show a decrease in control accuracy in

Motion planning and control of an autonomous mobile robot

The application of autonomous mobile robots (AMRs) has gradually become crucial in smart factories due to the advantages of improving production efficiency and reducing labour costs. Motion planning has been a key part of AMR control development. This paper presents motion planning and position tracking control systems of an omnidirectional wheel AMR powered by a hybrid fuel cell and battery power source. First, the kinematical and dynamic models of the AMR are introduced. The navigation system comprises three loops, with the first loop being motor control, the second loop being position tracking control, and a motion planning layer. The position data of the AMR for feedback control is obtained through sensor fusion of data from the inertial measurement unit (IMU) sensor, encoder sensor, and ranging sensor with simultaneous localisation and mapping (SLAM) algorithm. The motion planning is then applied to obtain an optimal path with the shortest distance and collision-free movement. In addition, the tracking algorithm is designed to drive the AMR to follow the optimal path and achieve high accuracy. The experimental results show a 30% improvement in tracking accuracy compared to traditional approaches and 8 hours of continuous working, which is promising for industrial applications, and the results are satisfactory in terms of both accuracy and efficiency requirements.

Kinematic and optimal design of a three-wheeled holonomic omnidirectional robot platform for mobile manipulation tasks

Mobile manipulator robots are increasingly vital in industrial and service sectors, serving roles in assembly, inspection, and hazardous environments. The integration of a manipulator with a mobile robot base imposes unique demands on the vehicle's drive system. This paper introduces a three-wheel holonomic omnidirectional robot designed for mobile applications. It explores kinematic equations, electronic integration, and mechanical design for holonomic motion. This platform excels in mobility, capable of simultaneous translation and rotation, facilitating precise multidirectional motion. Its equilateral truncated triangular structure ensures stability, supporting up to 4 kg. With three omnidirectional wheels and DC motors, controlled by EMS 30A H-Bridge and Arduino Mega 2560, it offers an open platform for research and development. This robust platform aligns kinematic calculations with mathematical models, promising efficiency for diverse mobile manipulation robot applications.

The Importance of the Fourth wheel in a Four-wheeled Omni Directional Mobile Robot-An Experimental Analysis

A four-wheeled Omni Directional Robot may travel in any direction without turning its wheels. In this research work, four Omni-directional wheels have been placed at 90°. This four-wheeled, omnidirectional mobile robot appears to be a square design from the top view, with its wheel axes at 90 degrees. Power is given to the front wheel using a DC motor and that wheel alone will rotate. All other three wheels (Right, Left and Back) are kept in neutral positions. These wheels can move based on the front wheel’s rotation. No power given to these wheels. Three different practical analyses have been done. In this first experimental analysis, the back wheel is kept as an Omni direction wheel. In this Second experimental analysis, the back wheel is kept as a Roller wheel. In this Third experimental analysis, the back wheels are removed and the other three wheels are kept and analysis is done. The importance of the back wheel in the four-wheeled Omni Directional Robot is demonstrated in this research work.

Magnetic Omnidirectional Wheel for Ferromagnetic Surface Cleaning Robots

Magnetic Omnidirectional Wheel for Ferromagnetic Surface Cleaning Robots

Motion Simulation of Autonomous Guided Vehicles

Autonomous Guided Vehicles (AGVs) using omnidirectional wheels can change their moving direction flexibly without the use of steering wheel. Is it possible that a vehicle with standard pneumatic wheels (as in a normal vehicle) change its moving direction flexibly by the technique of regulating the driving torque supplied to each wheel? In this article, the simulated motion trajectories of the two types of vehicles were presented, that are the vehicle using Mecanum wheels and the vehicle using standard pneumatic wheels (normal wheels). For vehicles with normal wheels, the simulation was carried out in two cases of motion direction control: with and without using a steering wheel. Further, the main loop of the motion direction control algorithm by regulating the driving torque to the wheels was also presented for a prototype of a vehicle with normal wheel, which was used to simulate the motion direction control experimentally. The topic will focus on motion simulation and the comparison of simulation results to evaluate the application ability of the mentioned technique in AGVs as well as in passenger cars.

Skywalker: A Compact and Agile Air-Ground Omnidirectional Vehicle

By taking the complementary advantage of multicopters and ground vehicles, air-ground vehicles have shown great potential in various fields due to their superior mobility and outstanding endurance. However, most of the previous works adopt complicated mechanisms, and fail to develop a controller with high precision for tracking challenging trajectories, which severely limits their application. In this work, we firstly propose the design of an air-ground vehicle, which we name as Skywalker, with a concise yet robust mechanism based on an off-the-shelf omnidirectional wheel. Furthermore, we deduce the vehicle's differential flatness considering support and friction forces, and propose a unified controller qualified for high-speed air-ground hybrid trajectory tracking and smooth mode switching. Meanwhile, comprehensive experiments and a benchmark comparison are carried out to validate the system's outstanding performance, where the system tracks trajectories under velocity up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\rm{5.0}~m/s$</tex-math></inline-formula> and saves energy up to 75.2%.

Development of a Three-Mobile-Robot System for Cooperative Transportation

AbstractThe transportation of large-scale objects in a narrow space is a challenging, but useful application for mobile robots. We have developed a three-mobile-robot system to cooperatively lift, support, and transport a large object on a mobile robot system. To facilitate the manipulation involved with loading an object onto the robots, where the robots must maintain firm contact with the object and anchor at its location, we designed an adaptable mechanism for the object-loading platform and a liftable brake to ensure that the robot remains stationary when necessary. Furthermore, each robot is designed to act as an omnidirectional wheel; therefore, all three robots can work as an omnidirectional block when collectively loading an object. The kinematic constraints of the object–robot system and forward kinematics of the robots’ cooperative motion are proposed, and experiments are conducted to confirm the designed mechanisms and confirm that the robots can load an object and cooperatively transport it along the expected trajectory.

Implementation consensus algorithm and leader-follower of multi-robot system formation

Robot technology has recently been applied to many applications to help human activities. Mobile Robot is one of the most flexible robot technology. This research uses a mobile robot designed using an omnidirectional wheel for the movement mechanism. Coordination and control of multi-robots can be assigned to perform any task from a different kind of field. Therefore, this paper aims to develop a multi-robot system to form a formation to do the task. The multi-robot system consists of three units Mobile Robot. The formation system will be built based on a coordinate point determined by a consensus point. The leader-follower topology is used to determine the orientation of the robot. ROS (Robot Operating System) is used as middleware to create a multi-robot system. The Open Base package in Gazebo Simulator is also used to simulate the movement of the multi-robot. From three test scenarios, this research results show that all the robots can do and follow the tasks simulated in the Gazebo with an average accuracy of 88.14%. Furthermore, no feedback from the robot to the Gazebo Simulator affects the robot's accuracy average below 90%.

A Palm-Sized Omnidirectional Mobile Robot Driven by 2-DOF Torus Wheels

This letter proposes a palm-sized omnidirectional mobile robot with two torus wheels. A single torus wheel is made of an elastic elongated coil spring in which the two ends of the coil connected each other and is driven by a piezoelectric actuator (stator) that can generate 2-degrees-of-freedom (axial and angular) motions. The stator converts its thrust force and torque into longitudinal and meridian motions of the torus wheel, respectively, making the torus work as an omnidirectional wheel on a plane. In this paper, we build a control system of a piezo-driven 2-degrees-of-freedom torus wheel and evaluate its performance measures, such as the transient characteristics, the orientation accuracy and the payload capacity. An omnidirectional robot with the two torus wheels is constructed, and the feedback control for a desired planar motion is demonstrated. The design inspired by a ring torus represents the possibility toward the creation of an unprecedentedly simple, light, and compact 2-wheel omnidirectional robot.

Design and Motion Control of Spherical Robot With Built-In Four-Wheel Omnidirectional Mobile Platform

The objective of this paper is to propose a novel spherical robot with built-in four-wheel omnidirectional mobile platform. The employment of four-wheel structure helps to improve the friction coefficient and thus reduce the slipping motion. In addition, it increases the velocity augmentation factor, and thus compensation methods can be effectively implemented into the system to decrease the slipping motion further. Moreover, the traction force is increased and thus the loading capacity can be improved correspondingly. First, the schematic structure along with the operating principle of the proposed spherical robot is introduced. Then, the kinematic and dynamic models are formulated analytically. The slipping error between the omnidirectional wheels and the inner wall of the sphere is analyzed. The slip observer and the motion controller are designed, and their convergence is proved theoretically. Subsequently, simulation is conducted to validate the proposed slip observer that is in turn implemented into the motion controller. The trajectory tracking of the spherical robot on straight line and circle is verified. Following that, one research prototype of the spherical robot with built-in four-wheel omnidirectional mobile platform is developed. Experimental investigation shows that the research prototype embedded with the slip observer can achieve the trajectory tracking performance very well.

Development an Omni-Directional Wheels with Small Diameter and High Load Capacity

Development an Omni-Directional Wheels with Small Diameter and High Load Capacity

Control system architecture of an intelligent humanoid robot

This paper presents the hardware and control software architectures of an intelligent humanoid robot. The robot has a mobile base consists of three omnidirectional wheels that allows it to move freely with three degree-of-freedom (DOF), two 6-DOF arms and 3-DOF neck and head that allows it to perform most of the common movements of human. Detail hardware components are given to show our mechanical design solution of the robot. The control software structure of the robotic system is constructed in the robot operating system (ROS) framework which is mainly used as a bridge to connect the control modules and various peripheral devices to ease our robot system task management. We have also shown the detail structure of the robot control system which consists of all key control modules which enable the robot functions: from upper level with AI-based techniques such as image and sound processing to middle level with the robot motion controllers and then to the lower level with the management of atuators and sensors. The proposed architecture is being developed and tested on a real humanoid robot prototype called Bonbon to support Enghlish teaching in elementary schools.