This project describes the collaboration of two instructors, one from the mechanical engineering department and one from the mathematics department with a group of mechanical engineering students to build and analyze a new type of transportation transmission. Current transmissions have torque limitations when working at various vehicle loading conditions. The ideal vehicle transmission is a continuously variable transmission that delivers optimum torque at any loading condition. The motivation for this research project is to design a new transmission that would increase the number of gear ratios using a chain element, and consequentially, increasing the number of available torques to achieve better overall vehicle performance. The new transmission consists of two planetary gears systems linked by a chain. It includes multiple inputs and outputs with the possibility of using one of the outputs to drive other engine components. The system is currently investigated for all possible gear ratios and usable torque configurations. The gear ratios are determined using Willis’s formula for planetary gear systems. All possible gear combinations are investigated and their gear ratios mathematically determined. A prototype was designed and built. It is being automatized, currently.

Deep hole drilling is required to install prosthetic devices in surgical implantation. Compared to the common bone drilling processes, deep hole bone drilling is performed with a larger hole depth (i.e., up to a depth of approximately 35 mm in cochlear implantation) using a high ratio of the length to diameter of the drill bit. For successful outcomes from this process, forces must be controlled adequately to avoid other complications such as drill-bit breakage or thermal necrosis. This study investigates the thrust force and torque generated in bone drilling process of up to 36 mm drilling depth. Drilling tests were performed on bovine cortical bone using 2.5 mm diameter twist drill bit with a spindle speed of 3000 rpm, and feed rates of 0.05, 0.075, and 0.1 mm/rev. Two distinct states in both the thrust force and torque data were observed for all conditions, which are called normal and abnormal states in this study. At an early stage of the drilling process, the force signals showed the traditional trend, reaching a constant value once the tip of the drill bit was fully engaged in bone cutting up to a certain depth. After that, both thrust force and torque kept increasing rapidly until the final drilling depth. This study also observed that the chip morphology varies with increasing drilling depth, showing fragmented chips at the normal state and powdery chips at the abnormal state. Chip clogging and increased frictional force between chips, tool, and hole wall with larger drilling depth may cause the abrupt increase in forces and variation in chip morphology.

Magnetic gearing is a developing technology that utilizes magnetic forces to transmit torque through a system. Unlike traditional gears that rely on teeth engagement to transmit motion and torque, interacting magnetic fields in a magnetic gear transfer the torque with no contact area required. Early magnetic gearbox designs stemmed from an electromagnetic design, however, at larger scales the assembly process as well as electromagnetic design drives the overall mechanical design, due to high magnetic forces and stresses during the assembly. The development of magnetic gearboxes involves the optimization of the assembly process, the electromagnetic design and the mechanical performance to achieve a design that is robust, efficient, manufacturable, and economical. Each of these attributes is necessary to advance the technical readiness for applications as varied as wind turbines or robotics. These qualities were sought in the design of two new magnetic gearboxes which have been manufactured and tested. The mechanical design of the multistage gearbox established a repeatable assembly process that could be upscaled without compromising the structural integrity of the components. Design variants were simulated and tested to limit bending and shear stresses in the gearbox, whilst maintaining the electromagnetic performance of the system. The mechanical design of the modular magnetic gearbox established a new rotor design where manufacturability and configurability were improved to make the gearbox ideal for applications that require varying gear ratios.

The Measurement While Drilling (MWD) tool is used by oil and gas industry to provide the directional survey information while drilling. With rig rates exceeding $1 million per day and wells that are drilled at depths of over 30,000 ft (9144 m), operators needs to have an MWD tool that can self-power itself to provide high data rates and strong signal strength. Among different types of MWD tool, the Continuous Mud-Pulse Telemetry (C-MPT) can generate high data rates and signal strength. The C-MPT has a rotating valve that propagates signal upstream through the drilling fluid in the drill string. However, the ability to power a C-MPT for the MWD tool using the existing hydraulic forces of the drilling fluid has not been extensively researched. The focus of this study was to propose the 2-lobe and 3-lobe turbo siren designs that can provide power to an alternator while maintain high data rates and signal strength. All turbo siren designs are based on a vein, rotor, and stator. The turbo siren systems were manufactured with 3D printing. An experimental wind tunnel was designed and built to simulate the downhole drilling environment. The testing results of the turbo siren systems are presented and discussed, including no-load rotation speed (RPM), stall torque, power and data rate. The results provide the guidance for the optimization of the self-powered MWD turbo siren design.

In order to investigate the performance and emissions behavior of a high compression ratio Compression Ignition (CI) engine operating in Partially Premixed Charge Compression Ignition (PPCI) mode, a series of experiments were conducted using a single cylinder naturally aspirated engine with a high-pressure rail fuel injection system. This included a moderately advanced direct injection strategy to attempt PPCI combustion under low load conditions by varying the injection timing between 25° and 35° Before Top Dead Center (BTDC) in steps of 2.5°. Furthermore, during experimentation the fuel injection pressure, engine speed, and engine torque (through variance of the fuel injection quantity) were kept constant. In-cylinder pressure, emissions, and performance parameters were measured and analyzed using a zero-dimensional heat release model. Compared to the baseline conventional 12.5° BTDC injection, in-cylinder pressure and temperature was higher at advanced timings for all load conditions considered. Additionally, NO x , PM, CO, and THC were higher than conventional results at the 0.5 N-m load condition. While PM emissions were lower, and CO and THC emissions were comparable to conventional injection results at the 1.5 N-m load condition between 25° and 30° BTDC, NO x emissions were relatively high. Hence, there was limited success in beating the NO x -PM tradeoff. In addition, since Start of Combustion (SOC) occurred BTDC, the resulting higher peak combustion pressures restricted the operating condition to lower loads to ensure engine safety. As a result, further investigation including Exhaust Gas Recirculation (EGR) and/or variance in fuel Cetane Number (CN) is required to achieve PPCI in a high compression ratio CI engine.

Magnetic gears are non-contact means of torque transmission which utilize the interaction of magnetic fields in place of the meshing teeth of mechanical gears to achieve a change in rotational speed and scale up/down the torque. A subscale magnetic gearbox featured a radial flux focusing arrangement consisting of three main rotors in the active region called inner, cage and outer rotors. In this arrangement, ferromagnetic cage rotor poles modulate flux between the inner rotor and outer rotor permanent magnets to achieve the gear reduction. Replacing the solid metal bars with laminated stacks for the cage modulating pieces as well as retaining pieces of the inner and outer rotor magnets reduces eddy current losses in the axial direction, a main source of losses in magnetic gears, while preserving the magnetic flux directed in the radial direction. Both of these features are key for overall system performance. Given the potential of demagnetization of the permanent magnets and damage to the components at high temperature, multiphysics thermal analysis is conducted on a subscale flux focusing magnetic gearbox to predict temperature distribution and thermal stresses. A conjugate heat transfer (CHT) method is used in a 3D academic code, FLUENT, to predict heat flux and the coupled non-adiabatic external flow field and temperature field on the inner, cage and outer rotor with a Finite Volume Method (FVM). Thermo-elastic behavior of the laminated components are assigned through anisotropic materialistic characters in a finite element method (FEM), where the thermal and centrifugal stresses are calculated.

This study outlines the design and optimization processes for the development of a multipurpose urban firefighting and disaster relief unmanned aerial vehicle (UAV). The design strives to attack and suppress fires that occur in high rise structures at heights greater than can be reached by ladder truck. The design also strives to deliver a payload of disaster relief supplies to affected areas, reducing risk to ground transport efforts. The study outlines the design and optimization of design components utilizing SolidWorks and testing of these components using SolidWorks Simulation and Flow Simulation packages. This study details the development of the final propeller and frame design, and the range of tests performed within SolidWorks to ensure the design can perform to the required standards. Given the dimensional advantages and torque cancellation capabilities a coaxial octocopter frame is developed. In designing and testing a propeller the proposed design is capable of producing a maximum thrust of 118 lbf. with a minimum factor of safety of 2.238. The propeller spacings are optimized to produce maximum thrust in both the coaxial and in-plane directions which are 23.6 inches and 25.6 inches respectively. For urban firefighting the selected hose and nozzle combination are capable of supplying 60 GPM of water at a height of 150 ft. from the ground. At this loading the minimum factors of safety of the frame and propeller are determined to be 2.238 and 3.034 respectively. The corresponding fatigue lives under prescribed number of cycles are determined to be infinite for both frame and propeller. Using rotorcraft theory, the theoretical hover time that the UAV can maintain in firefighting is determined to be 1.7 hours. Using a combination of SolidWorks Flow Simulation and aerodynamics theory the maximum velocity of the UAV at a pitch of 30 degrees from vertical, hauling a box with dimensions capable of carrying 200 lbs. of relief goods, is determined to be 85 mph. At disaster relief payload capacity the designed frame and propeller are capable of maintaining factors of safety of 3.226 and 3.034 respectively. These factors of safety correlate to fatigue lives of the frame and propeller of 15.98 years and 19.12 years respectively, under prescribed loading. The theoretical flight time the UAV can maintain for disaster relief is determined to be 1.618 hours. This study provides optimized propeller and frame designs along with selections of engines and other important components for building a multipurpose UAV.

Tidal current and wind energies have become dominant sources of renewable energies in the modern culture. In this work, the aerodynamic characteristics of a novel hybrid vertical axis turbine (VAT) have been studied in flow fields of water and air using CFD analyses. A parametric study was conducted on the hybrid rotor design with the goal of optimizing the solidity ratio to cover a wide operation range, increase initial torque and maintain high coefficient of power values. The hybrid turbine design with a solidity ratio of 0.5 demonstrated improvements to the self-startup feature and achieved the highest coefficient of power ( C p ) values of 44.5% and 50% in air and water flows, respectively. The results were in favor of utilizing this design in flow fields of water and air as an enhancement to previous literature. Further studies are required to assess the aerodynamic properties of the model in 3D CFD analyses.

In this work, a bow thruster is proposed to be used onboard small and medium-size watercraft, like motor yachts, fishing boats, patrol boats, ocean exploration vessels etc. with conventional or unconventional hull designs including displacement hull, planing hull, catamarans, SWATHs, SES, and so on. As oftentimes the case, a magnetic coupling is employed. Specifically, magnetic coupling is used to transfer torque from a brushless motor’s stator to its rotor through a magnetic field rather than a physical mechanical connection. Such magnetic coupling is very convenient for liquid pumps and as, in our case, propeller systems, since a static, physical barrier can be placed between the stationary and rotating part of the system to separate the fluid from the electrically supplied stator operating in air. Therefore, magnetic couplings preclude the use of shaft seals, which eventually wear out and fail from the sliding of two surfaces against each other. In this work, a system identification process of a rim driven bow thruster is implemented employing data series obtained by tests on a prototype scale model. System Identification leads to a black-box model of the system. The model derived can be extrapolated by grey-box modeling techniques for further design improvements. A control system for the proposed thruster is developed and validated through both computer and hardware-in-the-loop simulation, after its implementation onboard a broadly used industrial Programmable Logic Controller (PLC). The mathematical model of the bow thruster mechanism is developed and the performance is analysed by using Matlab/Simulink.

A gyroscopic power generator that generates 1.8 W by using a rotor of 100 mm diameter spinning at 500 rpm is developed. In conventional vibrational generators, which use simple vibrations of a inner pendulum, the output power has been less than 10 mW. Gyroscopic generators increase the inertial force by rotating the pendulum at high speed and generate about 100 times greater power than the conventional ones. However, gyro generators have not been able to operate under arbitrary vibrations at wearable sizes because they are unstable and easily stall by disturbances, and the gyro torque and the electromechanical transformation efficiency rapidly decrease by miniaturization. In this paper, first, a theoretical model is developed to clarify the basic characteristics of the generator. Next, a desktop-sized generator that works under any vibration is developed using highly precise motors and gears determined by the theory. Next, mechanical and electrical characteristics are measured to show the validity of the theory. Finally, the performance of wearable-sized generators is predicted to show the generators that have the same device size and rotor spinning speed as those of 2.5” and 3.5” HDD’s generate 0.74 W and 1.84 W, respectively.

Due to recent technological developments in advanced materials, the integration of shape memory alloys (SMAs) into new machines and mechanisms is becoming more common and it offers tremendous potential for the future. Using currently available properties of common SMA materials, the paper’s contribution is to: Study through dynamic simulation the potential offered by SMA springs to serve as the basis for rotary actuation. In the process, the SMA displaces a rocker arm rotating about an axis to induce rotational motion of a driveshaft, in effect converting a force into rotational motion. When embedded in a cycle with heating & cooling phases and a resetting mechanism, unidirectional rotational motion can be achieved. Regarding heating and cooling cycles, forced air convection is used to reduce thermal cycle cooling and is calculated via transient thermal analyses. Using typical parameter values for the representative design considered, through forced air convection, cooling cycles are reduced from approximately 30 seconds (natural) to 5.5 seconds (forced) and as a result, a complete system cycle can occur in 10 seconds, with the applied inertial load of 2.0 kg-m 2 . Using MATLAB and Simulink, a nonlinear 3 rd order dynamic system model was created and simulations were performed. One complicating factor concerned angular limits and the necessary thermal cycling, which was solved through appropriate sequencing and resetting of integrators for different phases. Simulation results for the design considered show that a peak torque of 1.72 N-m is possible and that relatively smooth motion and approximately constant torque output is also possible through the addition of a few more rocker arm systems, properly commutated. Lastly, the design analysis framework and results may inspire future realization of actual devices.

Cutting pressure models have long been utilized for calculating machining force components both tangential and normal. This work lists literature-reported closed form analytical models for torque and thrust of material cutting pressures. Typically, these models are equations formulated in terms of process parameters including mainly cutting speed (V, m/min), feed (f, mm/rev), and tool rake angle (α, degrees). This work aims to benefit from the variation in rake angle and cutting speeds encountered along the lip cutting edge of a standards twist drill to generate normal and tangential cutting pressure empirical models for aluminum 6061-T6 material based on a limited number of drilling feed rate and spindle speed combinations. To isolate the 10mm twist drill bit cutting edge forces, drilling experiments were conducted utilizing 2.5mm pre-cored workpieces. Cutting lip edge toque and thrust data were collected from conducted series of drilling experiments with total number of 10 varying combinations of feed rate and spindle speeds. Values of cutting pressure in terms of feed, speed, and rake angle parameters were identified using a custom-developed MATLAB ® code. Minimized is the difference between the cutting pressure-based closed form torque and thrust models versus the experimentally collected cutting lip torque and thrust measurements. Based on this MATLAB ® code, cutting feed, speed and rake angle parameters found around −0.2, −0.1 and 1.5 respectively based on a convergence criteria of 10 −10 and maximum iteration number of 1000. These optimized cutting pressure parameters were found to predict well the collected experimental forces and were found to be in line with parameter values as reported in the literature.

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.

As alternative to complex modeling, simple empirical equations that provide estimates of the chisel edge’s torque and thrust cutting force components are a useful tool for estimating chisel cutting forces. This work aim to develop a model capable of estimating torque and thrust forces generated by only the drill’s chisel edge as function of machining feed (f), cutting velocity (V), and chisel edge’s width (w). The chisel edge’s generated machining forces are quantified and statistically verified utilizing JMP-SAS/STAT ® design of experiment (DOE) software. An experimental setup involving 50 drilling tests was conducted with drilling feed, spindle speed and chisel web dimensions varied to enhance the statistical significance of the collected data. Experimental torque and thrust data were collected using a 4-channel rotary dynamometer (Kistler model 9123) at a 200 Hz sampling rate. Torque and thrust values encountered at the chisel edge were isolated from those of the full drill. Due to its wide industrial use, the workpiece material investigated is Aluminum 6061-T6. In-line with literature, reported values of experimentally collected data showed that chisel edge’s forces increased with drilling feed and drill bit web dimension while decreased with increasing speed (perhaps due to thermal softening). JMP-SAS/STAT ® module, nonlinear fitting with convergence criteria of 10 −15 and 70 iterations was utilized The developed model equations allow the estimation of the forces encountered at the chisel edge of a classical twist drill while cutting aluminum alloy 6061-T6 material.

The present study addresses physical phenomena of a suspension composed of magnetic spherical particles in an alternating magnetic field in order to elucidate particle aggregation phenomena and their influence on heat production. For this objective, we have performed Brownian dynamics simulations in a variety of circumstances of the magnetic field strength and frequency of an alternating magnetic field, and the magnetic dipole-dipole interaction strength. As in a time-independent uniform external magnetic field, large aggregates are formed in the case of strong magnetic particle-particle interactions. However, these clusters exhibit completely different behaviors that are dependent on the frequency of an alternating magnetic field. If the frequency is significantly high, then the viscous torque is the dominant factor, so that the formation of the clusters is not significantly influenced by the time-dependent magnetic field. If the frequency is significantly low, the magnetic field have a significant effect on the rotational motion of the particles, so that the formation of the cluster is dependent on which factor dominates the particle motion between the applied magnetic field and the magnetic particle-particle interaction. If the magnetic interaction is more dominant than the external field, stable chain-like clusters are formed in the field direction, and the magnetic particle-particle interaction induces a significant delay for the moments inclining in the alternating magnetic field direction. This behavior gives rise to a hysteresis loop with a larger area and therefore a large heating effect is obtained.

Journal bearings of high torque diesel engines are used to cater for high combustion loads which are applied intermittently. A lubrication layer is provided between journal (crankshaft) and bearing to avoid contact between them. The relative velocity between crankshaft and journal bearing results in viscous shear heating among the different layers of lubricating oil. The shear heating reduces the viscosity of the lubricant that ultimately reduces the load carrying ability of the journal bearing. It offers a physical contact and reduces the designed life of crankshaft. In this study the 2-D transient numerical lubrication model is developed by employing the Reynolds equation to calculate the pressure and film thickness profiles as a function of crankshaft speed. The shear heating effects are determined by coupling the energy equation with lubrication model. The finite difference method is used and an appropriate numerical scheme is employed to simulate the conduction and convection based thermal energy transfer in transient and steady state journal bearing lubrication model. The lateral displacement of crankshaft is incorporated in the thermal model to analyze the effect of secondary dynamics of crankshaft. The viscosity and temperature relationship are used to ascertain its variation with temperature. The characteristic of three different viscosity-grade lubricates are incorporated separately in the model to carry out the comprehensive comparative analysis. The results are simulated for particular application where low operating speed and length to width ratio of journal bearing is fixed and analyzed the results for complete 720 degrees of crankshaft in its two revolutions. The results show that the oil with high viscosity produces high hydrodynamic pressures as compared to the oil that have low viscosity. The viscous shearing temperature reduces the hydrodynamic pressures but still the high viscosity lubricating oil have enough pressures to uplift the shaft after incorporating the shear heating effects. This study determines the hydrodynamic pressure, and variation of density, viscosity and thermal-conductivity with temperature for three different lubricating oils. These analyses will facilities towards the selection of appropriate lubricant for high torque low speed diesel engine in order to enhance the life of crankshaft.

Drum brakes have dominated the braking industry for many years due to their low cost and adequate operating performance. In this paper, the authors present the first example of studying the sensitivity analysis of a magnetorheological fluid (MRF) and a conventional frictional brake by using first order Tayler series expansion. Nondimensional analyses are carried out to generalize the analyses for every brake configuration. This paper seeks to step away from the complexity of the numerical models for these brakes. Taylor series expansion is used to examine the effects of perturbing dimensionless design parameters on the braking torque. In addition, Taguchi approach is applied for the brakes to study the contribution of the design parameters on the braking torque and to obtain the optimal design. It is shown in this paper that braking torque for magnetorheological fluid brake is dependent on seven dimensionless groups while the frictional brake is dependent upon only four dimensionless groups. Four groups of the MRF brake and two groups for the frictional brake dominate the physics of braking. The sensitivity analysis has identified the key parameters that must be adjusted in order to increase braking torque. Furthermore, Taguchi approach has showed the how the variations of input variables affect the variations of the output variable and stated the optimal levels of the design parameters that achieve the optimal design.

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 paper presents a detailed dynamic modeling of phantom ax12 six-legged robot using Matlab SimMechanics™. The direct and inverse kinematic analysis for each leg has been considered in order to develop an overall kinematic model of the robot. Trajectory of each leg is also considered for both swing and support phases when the robot walks with tripod gait in a straight path. Newton-Euler formulation has been utilized to determine the joint’s torque. These results were verified using SimMechanics™. Also, feet force distributions of the hexpaod are estimated via SimMechanics™, which is necessary for its control.

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.