Mecanum Wheels Research Articles

A Human-Robot Interaction for a Mecanum Wheeled Mobile Robot with Real-Time 3D Two-Hand Gesture Recognition

Human interaction with mobile robot becomes a popular research area and its applications are widely used in industrial, commercial and military fields. A two-hand gesture recognition method with depth camera is presented for real-time controlling the mecanum wheeled mobile robot. Seven different gestures could be recognized from one hand for mobile robot navigation and three gestures could be recognized from the other hand for controlling the gripper installed on the robot. Under the proposed control scheme, the mobile robot system can be navigated and can be operated at the same time for achieving missions by two different groups of hand gestures. The accuracy of the gesture recognition is about 94%. During mobile robot control experiment, the system works timely, accurately and stably for certain tasks such as directional movement, grasping and cleaning obstacles.

모듈 결합형 전방향 이동 플랫폼의 기구학 모델 및 검증

With the increasing worldwide demand to automate product distribution, technology firms are introducing various mobile robots to the market. Generally, the maneuverability of the mobile robot is determined by the type and location of its wheels. Omnidirectional mobile platforms suitable for the agile motion required during instantaneous obstacle avoidance are widely used in congested environments like indoor factories. Previous omnidirectional mobile robots have been developed for specific purposes that prevented operation beyond the predesigned limits. To overcome this, we propose an omnidirectional mobile platform that can be connected to another platform. This type of modular structure can improve the efficiency of the entire logistics network by allowing flexible deployment according to the workload. The proposed system is able to generate holonomic movement with four mecanum wheels, and can connect with different mobile platforms using a connecting module at the side of each platform. To derive the kinematic model of the connected mobile platform, we first derive the analytical kinematic relationship between the connected platform center and each wheel. Next, we conducted simulations using RecurDyn, a dynamic simulation program, for three different types of connected mobile platforms. Our simulation results show that the position and velocity trajectory derived from the kinematic model well follows the reference trajectory at different connection cases.

Model Predictive Fault Tolerant Control for Omni-directional Mobile Robots

This paper describes the design of a Fault Tolerant Control scheme for an omni-directional mobile robot with four mecanum wheels. We consider actuation faults in which the wheels are not able to receive commands, but still can rotate freely due to the friction with the ground. A Non-linear Model Predictive Controller is employed, in order to appropriately exploit the inherited actuation redundancy of the omni-directional robot, and provide on the fly a unified accommodation solution for multiple combinations of actuation faults. A basic Fault Detection and Isolation scheme is responsible for identifying and isolate the faulty wheels. Accordingly, the control input vector and consequently the dynamic model of the vehicle are reformulated depending on the identified faults. Hence, the predictive control scheme is dynamically updated and calculates the optimal actuation solution, given the faults occurred. The proposed scheme, is able to guide the vehicle to any goal configuration within the workspace, while simultaneously satisfying state (e.g obstacle avoidance) and input (e.g motor limits) constraints. The efficacy of the proposed scheme is evaluated via a set of realistic simulation scenarios, where an omni-directional mobile robot executes a way point tracking mission with obstacle avoidance, inside a restricted workspace and in the presence of different combinations of actuation faults.

Analysis of the Mecanum wheel arrangement of an omnidirectional vehicle

Mecanum wheels are widely used in omnidirectional vehicles, but their arrangements are usually arbitrarily selected. We find that the arrangement of Mecanum wheels influences the performance of an omnidirectional vehicle. The two most used arrangement modes, Type-X and Type-O, are studied. The inverse velocity Jacobian matrix of the arrangement judges whether a vehicle can fulfill omnidirectional movement. The eigenvalues of the inverse velocity Jacobian matrix and global stiffness index are proposed to evaluate the stability and dexterity of different arrangement modes. The theoretical results show that the Type-X vehicle has a larger stiffness and global stiffness index than the Type-O vehicle, which ensures that the Type-X vehicle moves more precisely and stably than the Type-O vehicle. Four types of movements (straight, sideways, diagonal, and revolving) are tested for both arrangements. The experiments show that the actual running tracks of Type-X follow the ideal running tracks well, while the performance of Type-O is much worse. Moreover, an external force is subjected to both arrangements. The results illustrate that the behavior of the Type-X vehicle is more stable than that of Type-O.

Mobile environment of Omni-directional Vehicle with Mecanum Wheels

Mobile environment of Omni-directional Vehicle with Mecanum Wheels

Dynamical Obstacle Avoidance of Task- Constrained Mobile Manipulation Using Model Predictive Control

Task-constrained motion planning (TCMP) is involved in many practical applications, such as opening the door, opening the drawer, twisting the screw, and so on. Because of the trend of man-machine collaboration and the existence of dynamic in environments, planning the collision-free motions for task-constrained manipulation is a significative problem. This paper explores the TCMP issue for mobile manipulation, which uses a mobile base to enhance the working range and flexibility but simultaneously makes the problem harder than that of single manipulation because of the additional degrees of freedom (dofs). We propose an optimization-based method to plan the obstacle avoidance motion in real-time. First, the global robotic Jacobian matrix that combines the omnidirectional base and the robotic arm is derived. Second, model predictive control is used to plan the control rule in order to maximize the closest distance between the obstacles and the mobile manipulator and minimize the velocities of null space at the same time. We have deduced the model with four differential equations that represent the law of the distance over time. Third, the distances are calculated and sent to the model to calculate the velocity of each joint of the arm and the base using ACADO that is an open-source toolkit. Using the velocities, the mobile manipulator can move away from the approaching people while still fixing the end of the arm to manipulate tool at the same time. Our method is verified on the mobile manipulator that consists of four Mecanum wheels, a base, a UR10 arm, and four kinect cameras in Gazebo simulation with using the ROS operation.

Анализ сингулярных конфигураций мобильного манипулятора KUKA youBot

The article considers the KUKA youBot mobile manipulator with open software, which is intended for research and education purposes. Singular configurations of this apparatus have not been described in the literature as yet. The KUKA youBot system is a controlled platform, on which a five-axis manipulator with a grip is mounted. The platform can be moved in the horizontal plane by means of four mecanum wheels. The robot position in the absolute space is determined by eight generalized coordinates. As is known, the KUKA youBot inverse kinematics problem allows its exact analytical solution to be obtained. A rectangular Jacobi matrix for mapping the space of the robot generalized coordinates into the space of its end effector location parameters is constructed. The obtained Jacobi matrix is transformed to an equivalent echelon form by means of elementary operations. An analysis of the echelon matrix entries carried out using analytical tools has shown that, whatever the locations of the KUKA youBot system’s platform and the system arm first, fourth and fifth links, there is a singular configuration in which the robot's arm second and third links are stretched along the vertical line. In this case, the Jacobi matrix rank becomes equal to five (less than its full rank equal to six). When being in the above-mentioned singular configuration, the KUKA youBot system end effector cannot perform some of the movements the pattern of which is described in the presented paper.

Development of Universal Wheelchair Transporter

This work introduces a new universal wheelchair transporter to transport a conventional wheelchair from one point to another. The chosen design concept had been selected using Pugh chart selection method [13], considering all aspect contributed that give the highest weightage. The 3D design utilized CATIA software to visualize the product. Mecanum wheels were chosen to move the platform due to its flexibility and maneuverability in any direction without turning the universal transporter. The objective of this project is to develop a fully functional universal wheelchair transporter to transport a patient from one room to another room in the hospital. The performance of the product design is then tested using Finite Element Analysis and shows good results.

General Model of an Omnidirectional Mobile Robot Suitable for Uneven Ground

Mecanum wheels are used when omnidirectional movability of a vehicle is desired. For achieving the movability it is important to have a model of this omni-directional platform. In order to apply the omni-directional vehicle with four Mecanum wheels both to plane ground and to uneven ground, this paper presents a general model. Firstly the kinematics and the dynamics of the model on plane ground are presented. Then it is presented that there are mainly four types of uneven ground and four classes of touch states between the Mecanum wheels and the uneven ground in common buildings. A kinematical model which is suitable for the uneven ground is illustrated. It is proved that this model is also suitable for plane ground. A mobile robot control system was established by using Simulink module of MATLAB.

Neural network adaptive sliding mode control for omnidirectional vehicle with uncertainties

This paper presents a novel neural network adaptive sliding mode control (NNASMC) method to design the dynamic control system for an omnidirectional vehicle. The omnidirectional vehicle is equipped with four Mecanum wheels that are actuated by separate motors, and thus has the omnidirectional mobility and excellent athletic ability in a narrow space. Considering various uncertainties and unknown external disturbances, kinematic and dynamic models of the omnidirectional vehicle are established. The inner-loop controller is designed based the sliding mode control (SMC) method, while the out-loop controller uses the proportion integral derivative (PID) method. In order to achieve the stable and robust performance, the artificial neural network (ANN) based adaptive law is introduced to model and estimated the various uncertainties disturbances. Stability and robustness of the proposed control method are analyzed using the Lyapunov theory. The performance of the proposed NNASMC method is verified and compared with the classical PID controller and SMC controller through both the computer simulation and the platform experiment. Results validate the effectiveness and robustness of the NNASMC method in presence of uncertainties and unknown external disturbances.

Robust neural networks control of omni-mecanum wheeled robot with hamilton-jacobi inequality

This paper presents a novel approach to the problem of controlling mechanical objects of unspecified description, considering variable operating conditions. The controlled object is a mobile robot with mecanum wheels (MRK M). To solve the control task, taking into account compensation for nonlinearity and the object variable operating conditions, the Lyapunov stability theory is applied, including the Hamilton-Jacobi (HJ) inequality. A neural network with basic sigmoid functions is used to compensate for the nonlinearity and variable operating conditions of the robot. A simulation example is provided in order to evaluate the analytical considerations. The simulation results obtained confirmed high accuracy of the predicted robot motion in variable operating conditions.

An interactive control system for mobile robot based on cloud services

An interactive control system for mobile robot based on cloud services

An Adaptive Robust Controller for a Mobile Robot Driven by Mecanum Wheels

An adaptive sliding mode controller was designed for a mobile robot driven by four mecanum wheels.The original contribution of this paper is employing adaptive robust controller to mecanum wheels driven mobile robot for obtaining better tracking and robustness performance.To complete the design of the controller, the kinematic model of the mobile robot driven by mecanum wheels was firstly proposed.An adaptive robust controller was designed subsequently.A sliding surface was designed in Proportional-Differential-Integral form, which satisfied the robustness requirements of the system.Besides, a reaching law which has quick convergence was introduced, which reduced the time consumed by the setting parameters and resisting external disturbance.The controller was demonstrated in the presence of impulsive disturbance and sinusoidal signal disturbance, which proved the superiority of the proposed controller.Finally, an experimental verification of trajectory tracking was implemented to verify the practicability and effectiveness.

Optimal Control of an Inverted Ball-Driving Robot Based upon Slip Patterns

This paper proposes a precise driving control algorithm by utilizing the slip pattern of an inverted ball-driving robot with Mecanum wheels. The slip pattern of the ball-driving robot has an eight-leaves flower shape, which can be utilized to plan the driving direction of the ball-robot and to minimize the slip. When there exists the slip, the localization of the ball-robot becomes very coarse because of the uncertainties caused by the slip. By minimizing the slip using the analyzed slip pattern, the precise driving of the inverted ball-driving robot with Mecanum wheels can be achieved. Real experiments with a self-manufactured ball-robot have been carried out to show the preciseness of the driving based upon the proposed algorithm compared to the conventional algorithms.

Trajectory Tracking of an Omni-Directional Wheeled Mobile Robot Using a Model Predictive Control Strategy

This paper addresses trajectory tracking of an omni-directional mobile robot (OMR) with three mecanum wheels and a fully symmetrical configuration. The omni-directional wheeled robot outperforms the non-holonomic wheeled robot due to its ability to rotate and translate independently and simultaneously. A kinematics model of the OMR is established and a model predictive control (MPC) algorithm with control and system constraints is designed to achieve point stabilization and trajectory tracking. Simulation results validate the accuracy of the established kinematics model and the effectiveness of the proposed MPC controller.

Modeling and Kinematics Simulation of a Mecanum Wheel Platform in RecurDyn

The innovative method of modeling and kinematics simulation in RecurDyn are proposed, taking a Mecanum wheel platform(MWP) for omnidirectional wheelchair as research object. In order to study the motion characteristics and mobile performance of the MWP, the virtual prototype simulation model is established in SolidWorks, and virtual prototype simulation is carried out in RecurDyn. The experience of simulation for the MWP in RecurDyn is introduced, and the simulation steps and points for attention are described detailedly. The working states of the mobile system in real environment have been simulated through virtual simulation experiments. Four typical motion models including moving forward, moving laterally, moving laterally in the direction of 45°, and rotation have been simulated in RecurDyn. The simulation results exactly reflect the motion of the MWP. By comparing the simulation results with the theoretical results, there are acceptable errors that are relatively less overall in the simulation results. The simulation results can be used to predict the performance of the platform and evaluate the design rationality, and design quality can be improved according to the exposed problem. This paper can provide reference for the simulation of mobile platform by using RecurDyn.

Development of Stair Climbing Device Using Crawler and Mecanum Wheel

Development of Stair Climbing Device Using Crawler and Mecanum Wheel

Towards an Elevated Work Robot: the Traveling Performance of the Developing Omni-directional Inverted Pendulum Type Mobile Platform using Mecanum Wheels and/or Omni-wheels

Towards an Elevated Work Robot: the Traveling Performance of the Developing Omni-directional Inverted Pendulum Type Mobile Platform using Mecanum Wheels and/or Omni-wheels

Power-minimization and energy-reduction autonomous navigation of an omnidirectional Mecanum robot via the dynamic window approach local trajectory planning

To improve the energy efficiency of the Mecanum wheel, this article extends the dynamic window approach by adding a new energy-related criterion for minimizing the power consumption of autonomous mobile robots. The energy consumption of the Mecanum robot is first modeled by considering major factors. Then, the model is utilized in the extended dynamic window approach–based local trajectory planner to additionally evaluate the omnidirectional velocities of the robot. Based on the new trajectory planning objective that minimizes power consumption, energy-reduction autonomous navigation is proposed via the combinational cost objectives of low power consumption and high speed. Comprehensive experiments are performed in various autonomous navigation task scenarios, to validate the energy consumption model and to show the effectiveness of the proposed technique in minimizing the power consumption and reducing the energy consumption. It is observed that the technique effectively takes advantage of the Mecanum robot’s redundant maneuverability, can cope with any type of path and is able to fulfil online obstacle avoidance.

Design and adaptive control of omni-directional mobile platform with four driving wheels

In this paper, a general kinematic model of the four drive wheel omnidirectional mobile platform is established, and the CMAC (Cerebellar model articulation controller) +PID joint control strategy is used to design the embedded adaptive control of the omnidirectional mobile platform in view of the problem that the conventional control can not be self-tuning online and the real-time response of the response needs to be improved. The MATLAB simulation and experimental analysis of DC motor speed regulation were carried out, and the motion performance of the prototype was tested by a series of typical experiments. The results show that the kinematic model of the mecanum wheel omnidirectional moving platform is reasonable. The dynamic response of the CMAC+PID adaptive controller is fast, the control precision is high, and the robustness is good. The prototype can achieve the horizontal / vertical translation, the original rotation and the omni-directional motion in the plane. The overall performance can meet the requirements of the engineering application.