An Experimental Method to Calculate Coefficient of Friction in Mecanum Wheel Rollers and Cost Analysis Using DFMA Techniques

Mecanum wheel is a special kind of omni-directional wheel which is designed for robot vehicles. The purpose of this thesis is to work on geometry and working of Mecanum wheel rollers and to conduct experiments on these rollers to find its values of coefficient of friction in different conditions. This thesis also includes the work conducted to formulate the equations which can be used to find different parameters of roller for its motion, kinematics, rolling, friction and overall impact with respect to the working of a robot. The work is tested in experiments and the values are compared with previous research values to validate the data. At the end, the derived components are tested in DFM (Design for Manufacturing) and DFA (Design for Assembly) to calculate all possible cost factors in manufacturing and assembly of rollers. This research is done with the support of a company called Helical Robots. Helical Robots is a leading manufacturer of Mecanum wheels and robots

Modeling of the youBot in a serial link structure using twists and wrenches in a bond graph

We present a walk-through tutorial on the modeling of a complex robotic system, like the newly developed desktop mobile manipulator youBot developed by KUKA[5, 4]. The tutorial shows the design of models for typical robotic elements, done in a reusable object-oriented style. We employ an energy-based approach for modeling and its bondgraph notation to ensure encapsulation of functionality, extendability and reusability of each element of the model. The kinematic representation of mechanical elements is captured using screw theory. The modeling process is explained in two steps: first submodels of separate components are elaborated and next the model is constructed from these components

A reduced actuation mecanum wheel platform for pipe inspection

This paper focuses on the design, development and assessment of a novel, 2 degrees-of-freedom magnetic pipe inspection robot. It consists of 4 mecanum wheels, with the diagonals functionally coupled and the system rotation constrained by the surface geometry, maintaining full translational mobility with reduced control and actuation requirements. The system uses positional encoding that is decoupled from the transmission system to overcome the main sources of positional/positioning errors when using mecanum wheels. The kinematic and dynamic models of the system are derived and integrated within the controller. The prototype robot is then tested and shown to follow a scan path at 20mm/s within ±1.5mm whilst correcting for gravitational drift and slip events

Behavioural Fault tolerant control of an Omni directional Mobile Robot with Four mecanum Wheels

This paper analyses the four-mecanum wheeled drive mobile robot wheels configurations that will give near desired performance with one fault and two faults for both set-point control and trajectory-tracking (circular profile) using kinematic motion control scheme within the tolerance limit. For one fault the system remains in its full actuation capabilities and gives the desired performance with the same control scheme. In case of two-fault wheels all combinations of faulty wheels have been considered using the same control scheme. Some configurations give desired performance within the tolerance limit defined while some does not even use pseudo inverse since using the system becomes under-actuated and their wheel alignment and configurations greatly influenced the performance

Wheeled Mobile Robots: State of the Art Overview and Kinematic Comparison Among Three Omnidirectional Locomotion Strategies

In the last decades, mobile robotics has become a very interesting research topic in the feld of robotics, mainly because of population ageing and the recent pandemic emergency caused by Covid-19. Against this context, the paper presents an overview on wheeled mobile robot (WMR), which have a central role in nowadays scenario. In particular, the paper describes the most commonly adopted locomotion strategies, perception systems, control architectures and navigation approaches. After having analyzed the state of the art, this paper focuses on the kinematics of three omnidirectional platforms: a four mecanum wheels robot (4WD), a three omni wheel platform (3WD) and a two swerve-drive system (2SWD). Through a dimensionless approach, these three platforms are compared to understand how their mobility is afected by the wheel speed limitations that are present in every practical application. This original comparison has not been already presented by the literature and it can be used to improve our understanding of the kinematics of these mobile robots and to guide the selection of the most appropriate locomotion system according to the specifc application

Development of a Semi-autonomous Holonomic Load Carrier with Multi-camera Perception

Master's thesis in Mechatronics (MAS500)This thesis documents the development of a load carrier capable of carrying ten advanced personal robots. The robots of concern are Segway Robotics’ Loomo,which are used for education purposes at the University of Agder. They are used at multiple locations on campus, and it is desired to develop a system that can effectively transport them around. The report covers the concept generation, mechanical design, electrical design and development of a navigation system. A simple and compact design was developed and built. To achieve holonomic drive, the rig was equipped with four mecanum wheels. A mechanical design process was performed tocome up with a solution for mounting the wheels to the rig. This included design of an axle and bearing calculations. Additionally, the stability of the rig had to be verified. Further on,to drive the mecanum wheels, four brushless dc motors were utilized. The system consist of multiple hardware components, which needed to communicate with each other. The solution for this is documented in this report

Designing Omni-Directional Mobile Robot Platform for Research

Machines, as a key workforce in manufacturing, mining, construction, are essential for industry, and socially. However, existing mobile robots’ designs do not provide enough mobility and maneuverability. This is one of the major factors that requires an improved design of mobile robot platform. This thesis is focused on designing an improved Omni-directional robot platform that has good mobility and maneuverability. To realize these conditions, a lot of criteria and constraints need to be considered in the design process. The conceptual design flows of this mobile robot are to satisfy the need of a mobile robot platform, establish Omni-directional mobile robot specifications followed by concept generation and concept selection. A full decomposition of Omni-directional mobile robot was done. This was followed by building a morphology chart to gather several ideas for those sub-functions of mobile robot. Combination of different types of sub-functions will generate several new Omni-directional mobile robot concepts. The concepts were drafted by using Three-dimensional (3-D) Computer Aided Designing SOLIDWORKS software. After concept generation, the concepts were evaluated by using weighted decision matrix method. The best concept was generated from 3-D design to get 2-D technical drawing and kinematics analysis. These analysis and results of the robot performance are presented in this thesi