With the advent and development of precision machining and manufacturing, the necessity to ensure quality of the produced parts for their longevity has grown as fast the advances in technology. One of the ways of achieving higher product lives has been through tighter tolerances on size and form characteristics. Thus, it is imperative that designers, manufacturers and quality inspectors understand the mathematical principles guiding these dimensional and form characteristics, and further utilize them, to the greatest degree possible, in the inspection equipment and tooling. One of the greatest benefits to mankind was the invention of wheel. It is inarguably evident how much of our lives depend on machines with rotating parts. From power stations to power tools, from the smallest watch to the largest car, all contain round components. In precision machining of cylindrical parts, the measurement and evaluation of roundness (also called circularity in ASME Geometric Dimensioning & Tolerancing, GD&T Y14.5) is an indispensable component to quantify form tolerance. Based on reference circles, this paper focuses on the four modeling methods of roundness. These are (1) Least Squares Circle (LSC), (2) Maximum Inscribed Circle (MICI), (3) Minimum Circumscribed Circle (MCCI) and (4) Minimum Zone or Minimum Radial Separation Circles. These methods have been explained in the context of their implications on design applications, advantages and disadvantages. This article also explores how these multitudes of parameters are to be understood and be incorporated into undergraduate engineering curriculum, and be taught as an improved toolkit to the aspiring engineers, process engineers and quality control professionals.

The objective of this research is to develop a Virtual Teach Pendant for Android Cellphones (VTPAC) that is able to communicate with the robot model in the Visual Components software ⌈1⌉ ⌈2⌉. The VTPAC is a force multiplier that allows users to gain valuable teach pendant experience in labs with few robots, and makes the actual real-world robot time more valuable. It is also like a graduated driver’s license where the student must prove some proficiency with the VTPAC before being allowed to get behind the wheel. The VTPAC will be used to operate the real robot system too and will allow people to be trained without using real robotic systems in very safe environment. The VTPAC can be used for industrial training and can be integrated in the academic programs, especially for online courses. In this research, the Fanuc LR Mate 200iC robot and the Visual Components software have been selected as a case study. These choices were made because of the easy access to the Fanuc LR Mate 200iC and this interface by reason of it can control the robot the same way as the Teach Pendant in the real world. Using the robot kinematic theory to understand the Teach Pendant commands, the code was developed such that it respects the operating mode of the robot and all the security operations needed. For the VTPAC development we used Python to communicate with the Visual Components software to work as a client for the software. This can allow users to utilize its own cellphone as the teach pendant and the software as the robot, having a more real experience in a safe environment. The VTPAC has been implemented and tested successfully.

The bottom hole assembly (BHA) of a modern drill string for directional drilling mainly comprises a drill bit, a rotary steerable system, and a measurement while drilling tool. The tools and subs used on a BHA are screwed together through rotary shouldered threaded connections. Each connection is made up with a pin and a box. These connections are the weakest links when the BHA undergoes a large number of revolutions in a curved well section. When the fatigue life of a connection is consumed during a drilling job, a twist-off would occur, which could result in an enormous amount of non-productive time and possibly loss of the bottom BHA section in the hole. Cold rolling has proven to be able to improve fatigue resistance of a threaded connection by pressing a rolling wheel against the thread root and generating a layer of compressive residual stress at the root. Understanding how cold rolling improves fatigue resistance of a threaded connection is important for optimization of the rolling parameters and prediction of the BHA service life in a given drilling condition. In this paper, a predictive method is presented for fatigue life of a cold rolled threaded connection. A finite element model was developed to simulate the cold rolling process. The resulting deformation and stress states at the root were carried over through makeup of the pin and the box as well as through cyclic bending of the connection. The fatigue life predictions were found to be in favorable agreement with the experimental measurements from full-scale fatigue tests at different bending moment levels applied.

This work was focused on the development of a hybrid engine which was fueled with three different fuels; gasoline as original fuel, Liquid Petroleum Gas (LPG) and biogas as two alternative fuels. The developed engine consisted of fuel storage tanks, a small gas reducer, a fuel premixer and the engine of a Suzuki Skydrive 125CC motorcycle. Performances of the prototype and developed engines were compared in terms of wheel speed. The developed engine could be started, idled and accelerated with the average maximum speed of 1276 revolutions per minute when it was connected directly with the biogas reservoir. Then, the biogas was compressed and stored in a standard gas tank which was connected with the developed engine, the average maximum speed of 1273.67 revolutions per minute was obtained from three experiments. This work emphasized not only biogas usage as the alternative fuel for the engine but also pointed out that biogas quality could affect the engine performance. The developed engine could be applied as vehicle engine or it could drive household self-power generators by using household biogas as fuel.

A simplified roll-plane model is proposed to assess the effect of the vertical position of the center of gravity of the body-cargo system, on the rail fatigue life. A set of assumptions are made to simplify the analysis, including neglecting the bogie’s dynamic contribution to the wheel-rail forces. Three performance measures are defined to assess the effect of different dedicated railway cars on the rail fatigue life, including the fourth-power law, the load dispersion, and the rail fatigue. The simulation results suggest that the vertical position of the center of gravity of the body-cargo set, severely affects the fatigue life of the railway material, with the two-stack car being the most aggressive. For example, twice as aggressive as the gondola car.

The use of robots in search and rescue operations has increased dramatically over the years. A robot is able to detect survivors of a dangerous situation, like an earthquake, without putting the operator’s life in danger as well. There are many types of robots being developed for search and rescue purposes, but a smaller and more durable robot will be beneficial for designs in the future. The purpose of our project is to research and design a soft body robot that is capable of locating individuals in search and rescue operations. The robot has a design similar to a car which will allow the control of the robot to be easy to use. It has been designed with a self-righting mechanism in case the vehicle flips over or gets stuck. The robot has a small size so that it can fit through small holes that a person could not enter. The robot will be capable of traversing over uneven terrain, including small ledges through an actuator. The actuator will be designed to cause the robot to spring over or on a ledge. According to simulations from SolidWorks, the wheels of the robot can also withstand a drop from 2 meters. The design and material of the wheels will be further tested and changed to increase the performance of the wheel. Once a design has been chosen, the body of the robot will be designed. Current designs of ground rescue robots will be studied in order to attain a better understanding on what designs work best. The hope is to make the robot more durable than previous designs using a soft material as the outer shell of the robot. A soft material should allow the robot to be able to absorb impacts from falling debris or unexpected falls. Once the design of the robot has been optimized, a prototype will be created. The next step will be to code the robot so that it can be controlled with a remote. The current proposal is to use an Arduino board to send and receive signals from that remote. Then a camera will be attached to the robot which will allow the operator to see where the robot is and where the survivors are located.

This paper studies and simulates the dynamics and controls for a two-wheeled robotic chassis that successfully and consistently self-balances. Previous approaches to similar models have derived their dynamics from first principles using Newtonian mechanics for a linearized, shared-axle system and Lagrangian mechanics for a linearized, independently-actuated system. As such, the derived dynamics do not often reflect important factors of real world models which are not linear. However, this study specifically focuses on a more complicated system with independently-actuated wheels, for which a sophisticated and realistic dynamic model is derived using non-linearized Lagrangian mechanics. The pendulum and cart movements are each assumed to be planar, and their planes of motion are defined perpendicular to each other. The system’s performance is then analyzed in the simulation environment to determine the effect of various controllers and filters in cases of full and partial state feedback with and without sensor noise. Performance is characterized in terms of pendulum angle relative to the vertical axis and cart trajectory relative to the ground plane, both of which are functions of the voltage-applied force on each wheel independently. A comparison of the results shows that the non-linearized Lagrangian model best fits the true data and yields less uncertainty given a sensor failure. Therefore, the presented study has high intellectual merits compared to existing studies which focus on only linearized models. Based on the deterministic parameters of this study’s non-linearized model, a recommendation is made about which combination of controllers and filters best maintains the system’s stability in the event of a sensor failure returning only partial state feedback.

This paper presents a mathematical model for multi-axle steering vehicles operating on level ground. For transporting heavy loads vehicles with multiple axles are required. Apart from added complexity steering of multiple axle for turning is a big challenge. Due to type of load being carried a single unit vehicle is sometimes preferred. The mathematical model of a six axle vehicle with 4-axle steering system is developed. Simulations at various track radii, vehicle speeds and steering ratios (ratio between the first, second, fifth and sixth steering axle) are performed. Axle steering angles and wheel slip angles are evaluated. The steering ratio requirements vary with vehicle speed and turn radius. A configuration is selected for better performance for a wider range. The resulting steering ratios show good vehicle maneuverability, stability and steering efficiency.

The automotive industry corporations noticed the advantages of automated laser welding. Robot laser welding systems have immediately attracted their interests for bringing down the production costs and delivering higher-quality items. The objective of this research is to study how to enhance heat dissipation to endorse a better performance of the pressure wheel, and help achieve a longer life cycle. Transient thermal analysis of the pressure wheel was conducted using ANSYS workbench. The work studied the effects of different design models and materials on the thermal performance of pressure wheel assembly during the cooling period. Numerical simulations were performed on both solid and geometrically ventilated wheels for enhancing the heat dissipation performance of the wheel. Different materials were also be tested and compared. The analysis will support the design process by monitoring different parameters in terms of performance, heat loss and manufacturing cost. A comparison was made for two different designs each with three different materials and the best design was selected. The simulation results in a period of 50 seconds cooling time showed that the temperature dropped with the 1st design (full solid wheel) made of tungsten from an initial temperature T i = 500 K to a final temperature of Tf = 434.5 K. Tungsten was found to have better heat dissipation compared to stainless steel and cast iron. For the 2nd design (geometrically ventilated wheel) made of tungsten, the temperature drops from T i = 500 K to Tf = 422.1 K. Comparing the two designs, the geometrically ventilated wheel was proved to be cooled faster. The present work will help improve the performance of pressure wheel in the welding industry by providing computational results for successive design testing and data validation.

Compared with other speed reducers, the two-stage cycloidal planetary one also known as RV reducer has higher precision, higher mechanical efficiency, higher loading capacity as well as long service life. These characteristics make it attractive for industrial applications, especially for robotics applications and machine tools, where high precision and large torque transmission are required. The traditional RV reducer uses cycloidal drive which is comprised of the cycloidal wheel and the pins. It has some disadvantages in the pin design, because of small clearance between the pin and the cycloidal wheel, the collision between the pin and the cycloidal wheel may lead to unstable stress in the key parts and output velocity fluctuation. This paper presents an innovative cycloidal planetary reducer using internal meshing principle instead of external meshing between cycloidal wheel and pins in traditional RV reducer. In the new design of the reducer, the internal teeth with cycloidal profile are processed inside the reducer housing, meshing with two pin holders which are placed at the inner side of the cycloidal teeth to achieve transmission. The pin holder is a new integral structure of pins integrated on a round plate. Then a comparison study is conducted through establishment of system dynamics analysis. The transmission characteristics and meshing force of both the new type of reducer and the traditional RV reducer are analyzed under the same condition of reduction ratio. The results show the new reducer improves on these shortcomings, its transmission performance is competitive as compared to traditional RV reducer. What’s even better is that its output speed is more stable, and the contact force between the pin position on the pin holder and the internal cycloidal teeth inside the reducer housing is smaller, as well as the contact frequency is obviously decreased.

Ni3Al based superalloy is a kind of intermetallics, it is a relatively new superalloy, its superior high temperature characteristic makes it the fifth generation aero-engine turbine blade material. The machinability of Ni3Al based superalloy is poor, and its process parameters have significant influence on grinding force and surface integrity. The creep feed grinding experiments of Ni3Al based superalloy IC10 were carried out with different process parameters. The experimental results show that the workpiece speed has the greatest effect on grinding force, surface roughness and 3D surface topography, followed by grinding depth, the wheel speed has the smallest influence. Grinding force is positively correlated with grinding depth and workpiece speed, and negatively correlated with grinding wheel speed. Similarly, surface roughness is positively correlated with grinding depth and workpiece speed, and negatively correlated with grinding wheel speed. The higher the workpiece speed, the deeper the grooves and the higher the peaks of the surface topography. In order to maintain high surface quality, small workpiece speed and grinding depth should be chosen during grinding process.

The complicated steel wheel and rail interaction on curve causes side wear on rail head. Thus, the cost of maintenance for the track on curve is significantly higher than that for track on a tangent. The objective of this research is to develop 3D printing technology for repairing the side wear. In this paper, the study examines induced residual thermal stresses on a rail during the cooling down process after 3D printing procedure using the coupled finite volume and finite element method for thermal and mechanical analysis respectively. The interface of the railhead and additive materials should conserve high stresses to prevent any crack initiation. Otherwise, the additive layer would likely shear off the rail due to crack propagation at the rail/additive interface. In the numerical analysis, a cut of 75-lb ASCE (American Society of Civil Engineers) worn rail is used as a specimen, for which a three-dimensional model is developed. The applied residual stresses, as a result of temperature gradient and thermal expansion coefficient mismatch between additive and rail materials, are investigated. At the beginning, the worn rail is at room temperature while the additive part is at a high initial temperature. Then, additive materials start to flow thermal energy into the worn rail and the ambient. The thermal distribution results from thermal analysis are then employed as thermal loads in the mechanical analysis to determine the von-Mises stress distribution as the decisive component. Then, the effect of preheating on residual stress distribution is studied. In this way, the thermo-mechanical analysis is repeated with an increase in railhead’s initial temperature. In thermal analysis, the temperature contours at different time steps for both the non-preheated and preheated cases indicate that preheating presents remarkably lower temperature gradient between rail and additive part and also represents a more gradual cooling down process to allow enough time for thermal expansion mismatch alignment. In mechanical analysis, the transversal von-Mises stress distribution at rail/additive interface is developed for all cases for comparison purposes. It is shown that preheating is a key factor to significantly reduce residual stresses by about 40% at all points along transversal direction of interface.

The effects of reduced kingpin offset distance at the ground (scrub radius) and speed were evaluated under controlled test conditions simulating front tire tread detachment drag. While driving in a straight line at target speeds of 50, 60, or 70 mph with the steering wheel locked, the drag of a tire tread detachment was simulated by applying the left front brake with a pneumatic actuator. The test vehicle was a 2001 dual rear wheel four-wheel-drive Ford F350 pickup truck with an 11,500 lb. GVWR. The scrub radius was tested at the OEM distance of 125 mm (Δ = 0) and at reduced distances of 49 mm (Δ = −76) and 11 mm (Δ = −114). The average steady state responses at 70 mph with the OEM scrub radius were: steering torque = −24.5 in-lb; slip angle = −3.8 deg; lateral acceleration = −0.47 g; yaw rate = −8.9 deg/sec; lateral displacement after 0.75 seconds = 3.1 ft and lateral displacement after 1.5 seconds = 13.1 ft. At the OEM scrub radius, responses that increased linearly with speed included: slip angle (R 2 = 0.84); lateral acceleration (R 2 = 0.93); yaw rate (R 2 = 0.73) and lateral displacement (R 2 = 0.59 and R 2 = 0.87, respectively). At the OEM scrub radius, steer torque decreased linearly with speed (R 2 = 0.76) and longitudinal acceleration had no linear relationship with speed (R 2 = 0.09). At 60 mph and 70 mph for both scrub radius reductions, statistically significant decreases (CI ≥ 95%) occurred in average responses of steer torque, slip angle, lateral acceleration, yaw rate, and lateral displacement. At 50 mph, reducing the OEM scrub radius to 11 mm resulted in statistically significant decreases (CI ≥ 95%) in average responses of steer torque, lateral acceleration, yaw rate and lateral displacement. At 50 mph the average slip angle response decreased (CI = 87%) when the OEM scrub radius was reduced to 11 mm.

This work proposes a method to simulate wheel lock of a Heavy Commercial Road Vehicle (HCRV) using pneumatic brake circuit on a brake dynamometer. The proposed methodology lumps the effects of wheel slip and load transfer during straight-line braking into ‘equivalent inertia’ on the wheels. This inertia profile could then be imported on a dynamometer interface and realized using suitable inertia discs and an electric motor. Equivalent inertia was computed from test datasets obtained from a Hardware-in-Loop (HiL) experimental system consisting of an air brake system and IPG TruckMaker ® , a vehicle dynamic simulation software. These datasets were obtained for various road, vehicle load and braking conditions. This framework would facilitate the evaluation of wheel slip regulation algorithms using a brake dynamometer by capturing necessary dynamics of HCRVs during braking. It is expected that such testing can be placed between HiL and on-road tests, and would provide greater confidence in Active Safety Systems (ASSs) before their deployment on vehicles.

This paper presents the design and implementation of a low-cost and reliable wireless motion control system for conventional electric wheelchairs. The presented work aims to enhance the mobility of handicapped and elderly wheelchair users by utilizing a mobile application to control the motion of their unattained wheelchairs. The designed system takes into consideration cost, weight, a range of operation, ease of use, and implementation. The conventional electric wheelchair is equipped with a motorized front wheel steering mechanism. In addition, it is equipped with a Wi-Fi module to support remote motion control via a specially designed Android mobile application called “Android Application For NavigAtioN”; AAFNAN for short. Experimental testing of the prototype showed successful remote motion control and ease of use.

Automobile Braking System is one of the most important sub systems of the vehicle. It is the primary safety system since the stopping of the vehicle is majorly dependent on this system. This system utilises the frictional force between the tire and the road to stop the vehicle. The braking force required by the vehicle is governed by two factors. One of them is the coefficient of friction between the tire and the road surface, the other one is the load on the vehicle. Thus, required braking force to halt the vehicle with the minimum possible stopping distance varies with the load in the vehicle. If the applied braking force is greater than the required brake force, wheel gets locked which results in increased stopping distance. In order to prevent the wheel lock at low load conditions, a variable braking force system is developed. In Motorcycles, the pillion load majorly contributes to the overall weight. Thus, the amount of braking force required to stop with minimum stopping distance also varies drastically with respect to pillion load condition. Hence, the amount of braking force developed between the road surface and the tire is varied in the variable braking force system. In this project, variable brake force system is achieved by varying the effective disc radius. The maximum braking force developed between the ground and the tire is controlled based on the pillion load on the motor cycle, if friction is present between the tire and the ground. Two calipers are mounted on the brake disc of which one is fixed at a constant distance (constant effective disc radius – 67mm) and the other is movable depending on the load on the motorcycle. The movable caliper slides upwards and downwards such that the effective disc radius is varied based on the pillion load. Using a load cell, the load of the vehicle is determined. A microcontroller is programmed to move the caliper with the help of a stepper motor based on the load on the motorcycle. This way, the effective disc radius is varied for various loads on the motorcycle.

The use of automobile lightweight is an effective measure to reduce energy consumption and vehicle emissions. The utilization of high-performance composite materials is an important way to achieve lightweight vehicles technically. The advantages of using thermoplastic composite wheels are: easy to form, high manufacturing efficiency, low cost and easy to recycle. This leads to broader application prospects. Taking composite anisotropy into consideration, the mechanical performance of a wheel made of long glass fiber reinforced thermoplastic (LGFT), is analysed using the finite element method (FEM). This is done by placing the wheel under a bending fatigue load simulation. According to the simulation results, the sample database is established by orthogonal experimental method on the Isight platform, and the approximate model is established by the Response Surface Methodology (RSM). Based on this model, uncertainty optimization analysis is then conducted on the wheel’s design using Sigma Principle whereby the optimization target is the mass minimization. The maximum deformation of the wheel and the stress on both sides of the spoke will serve as constraint conditions and the key dimension parameters of the wheel model will be taken as the design variables. The uncertainty optimization is based on the Sigma criterion, taking into consideration the wheel’s geometry and property-fluctuation materials. The feasibility of design schemes is then verified after comparison analysis between the optimization results and the simulation results obtained. The result shows that compared with deterministic optimization, though the weight of the wheel has slightly increased, the uncertainty optimization based on the Sigma criterion is much more robust and the reliabilities of the three constraints are all above 6 Sigma. The resulting optimized LGFT wheel weighs 5.28kg, which has a 5.5% more loss in weight than the initial target and is also 25.6% lighter than the counterpart wheel which is made of aluminum alloy. The desired design results is now achieved with this lightweight effect.

One of the most important safety features of an automobile is its braking system. The ability of a braking system to provide safe and repeatable stopping is the key to safe motoring. Mechatronics subsystems are more and more developed in automotive industries and in the recent years modern control techniques have been applied to a wide range of many electronic control systems in the automotive industry such as Anti-Lock Brake Systems (ABS). This article proposed an intelligent adaptive control for anti-lock braking system (ABS), to control the desired slip ratio that prevents wheels from locking. A Fuzzy controller having Gaussian memberships is developed to calculate the amount of reduction of the applied torque based on the error signal (the difference between the measured slip ratio and the desired slip ratio). Results of the proposed controller are compared with the results of a PID controller. The scheme is implemented using a quarter car model and simulation tests were carried out in different conditions. The simulation results show that the proposed scheme is robust and effective.

A prototype of a hovering multi-terrain mobile robot platform that makes use of a flywheel for stabilization and heading control for rapid maneuverability was developed and presented in a prior paper. It was shown that flywheel stored energy could be transferred to the overall body to generate rapid angular motion once wheel is instantaneously stopped. Solution improved localization accuracy and reduced the overall sensitivity with respect to external disturbances such as non-flat terrain. In this paper, we present a feedback control system to measure dynamic parameters before and after the wheel is stopped. System is designed to follow a predefined path plan and instantaneous torque change causes oscillation after a waypoint is reached. To address this issue, we updated system with an inertial measurement unit (IMU) as a feedback sensor. Then, we investigate the feedback control of individual forward thrust vectors as well as wheel braking timing to minimize amplitude of transient response oscillation and to reduce the steady-state error to an acceptable level that differential drive fans could compensate this error and correct the heading after the rotation around a waypoint occurs. In addition to that, previous mechanical system could transfer all energy stored at once and was not adjustable. In this research, we also investigate varying amount of angular inertia generated by fans and wheel individually and together. To do so, system is modified with stronger forward thrusters. Prior to running the system with a full dynamic model with real mechanism, we implemented a simulation to empirically extract system parameters and adjust controller gains to follow a predefined path with open and closed loop control schemas with objective of minimizing localization error. Finally system is tested with real mechanism. Governing equations, simulation and empirical results comparison are presented and generated trajectories of various simulation and real world settings are listed. Test results verify that, with a closed loop control system, overshoot and total error about a waypoint can be minimized to an acceptable level at and after transient response phase.

Holonomic motion is desired for mobile ground robots and vehicles as it provides omnidirectional maneuvering capabilities, which can simplify the task of navigating around obstacles in confined spaces and unstructured environments. Mobility platforms that utilize spherical wheels are gaining popularity and interest due to the agile maneuvering and ground traversal capabilities they enable for mobility platforms. Ball-driven mobility platforms have a rich design space as various design parameters are available that can modify the physical and performance characteristics of the platforms. Various configurations for ball-driven mobility platforms are presented along with a generalized kinematic model that can be used for calculating motor velocities for a desired vehicle velocity. A naming convention is also presented in the paper for differentiating between configurations used for ball-driven mobility platforms. Metrics such as platform footprint, platform stability, and actuation force and efficiency are used to compare the configurations and to highlight some of the trade-offs associated with the selection of a configuration. Promising configurations are highlighted based on the metrics selected for the comparisons.