Tilt Mechanism Research Articles

DETERMINATION OF LOAD CHARACTERISTICS OF A LINEAR ELECTROMECHANICAL ENERGY CONVERTER FOR THE TILT SYSTEM OF RAILWAY ROLLING STOCK

The article discusses the prerequisites for selecting the parameters of a Linear Electromechanical Energy Converter (LEEC) for the tilt system of railway rolling stock. Special attention is given to determining the required force to tilt the body to a specified angle and the load characteristics of the LEEC. To achieve this goal, a simulation model has been created that allows for the variation of geometric and physical parameters to obtain load characteristics for different configurations of the tilt mechanism. The obtained load characteristics are used to find the optimal placement of linear actuators in the tilt system.

Limit analysis on roof failure mechanism of tunnels subjected to sequential excavations

Compared to traditional full-face excavation methods, sequential excavation methods (SEM), such as central diaphragm (CD) and sidewall drift (SD) methods, can significantly reduce rock disturbance and minimize the extent of roof failure in tunnel crowns. Therefore, they are particularly suitable for tunnel projects in weak rock formations and large cross-sectional underground chambers. This paper presents a kinematic approach to predict the roof failure mechanism of tunnels excavated using the CD method. The collapse blocks at the top are influenced by excavation steps and initial in-situ stresses, and the direction of their failure velocity field is typically non-vertical, posing challenges for limit analysis applications. To address this, a tilted velocity field for the collapse failure of the tunnel crown in the CD method is constructed based on the initial normal stress distribution along the tunnel’s top contour, obtaining an upper bound solution for tunnel collapse failure. The proposed method is compared with the full-face excavation method, demonstrating the superiority of the CD method over the full-section method. The rationality of the proposed tilted velocity field mechanism is verified through numerical validation using finite difference methods. Building upon the upper bound solution, safety assessment indicators for tunnels excavated using the CD method, namely allowable rock stress release and safety factor, are proposed. Furthermore, we extend this method to analyze the roof failure mechanism in tunnels constructed using the SD method and confirm its effectiveness through comparison with FDM analysis. Theoretical analysis and numerical validation both indicate that sequential excavation methods can significantly reduce the potential collapse range at the top and improve the safety of tunnel construction.

Mass reduction possibilities of connector in tilt mechanism of steering wheel using topology optimization

Design, Analysis, test and validation process of a tilt mechanism of steering column is mentioned in this study. The steering column is designed with the purpose of assembling it in EV vehicle. In order to increase market share of this EV vehicle that has tilt mechanism in steering column, to reduce the cost. Moreover works on weight reduction, cost reduction. Key Word: ANSYS, Connector.

Aerodynamic Drag of a Tilt-Rotor UAV During Forward Flight in Rotary-Wing Mode

This paper examines the aerodynamic drag force acting on a tilt-rotor UAV that has three mini fans and a main rotor with a tilt mechanism. The mini fans are embedded in the nose and the left and right wings. The main rotor is located near the center of the vehicle, and its front half is surrounded by the trailing edge of the nose in rotary-wing mode. The downward airflow from the fans and the main rotor generates an aerodynamic drag force called momentum drag, which is linearly proportional to the airspeed of UAV. To verify the existence of momentum drag, parameter identification of drag coefficients is performed from experimental data where the UAV flies forward in rotary-wing mode. The drag force is also investigated using computational fluid dynamics simulations. These experimental and numerical results are consistent with theoretical results based on momentum theory.

Design Requirements for Personal Mobility Vehicle (PMV) with Inward Tilt Mechanism to Minimize Steering Disturbances Caused by Uneven Road Surface

The Personal Mobility Vehicle (PMV), which has an inward-tilting angle, turns with lateral force due to a large camber angle, so it is necessary to consider the lateral movement of the tire vertical load axis during turning. Although the steering torque mechanisms are very different from those of automobiles, there are not many studies of the steering torque mechanisms of PMVs. In this paper, based on the effects of the force of six components acting on the tires, a method for setting the steering axis specifications is derived, including the geometrical minimization of steering moment disturbance due to the vertical load reaction force during turning. Automobile tires have a significant ground camber angle when traveling on rutted roads, but they do not have it on slanted roads because the vehicle body tilts along the road surface. On the other hand, in PMVs, the vehicle body always keeps upright when traveling both on slanted roads and on rutted roads. Therefore, the tires have ground camber angles on both types of road surface. We study the straight running ability under such road surface disturbances based on the geometrical minimization of steering moment disturbance due to the vertical load reaction force during turning. This straight running ability can be a remarkable strong point of PMVs with an inward tilt mechanism. In this study, it was proved that the steering axis parameters can be derived uniquely by taking into consideration the requirement to zero the moment (disturbance) around the steering axis due to the reaction force against the vertical load at all internal tilt angles.

Thrust Vectoring Control of a Novel Tilt-Rotor UAV Based on Backstepping Sliding Model Method.

In this paper, a control method of a novel tilt-rotor UAV with a blended wing body layout is studied. The novel UAV is capable of vertical take-off and landing and has strong stealth capabilities that can be applied to carrier-borne reconnaissance aircraft. However, the high aspect ratio of blended wing body UAVs leads to a wingtip or oar-tip touchdown problem when adopting the conventional position-attitude control (CPAC) scheme with a large crosswind disturbance. Moreover, when the UAV is subject to interference during reconnaissance, aerial photography, and landing missions, the conventional scheme cannot provide both attitude stability and track accuracy. First, a direct thrust vectoring control (DTVC) scheme is proposed. The control authority of the rotor tilt mechanism was added to enable the decoupling of the attitude and trajectory and to improve the response rate and response bandwidth of the flight trajectory. Second, considering the problems of strong couplings and parameter uncertainties and the nonlinear features and mismatched perturbations that are inevitable in the tilt-rotor, we designed a robust UAV controller based on the backstepping sliding mode control method and determined the stability of the control system through the Lyapunov function. Finally, in the case of crosswire interference during vertical takeoff and landing and the aerial photography missions of the UAV, the numerical simulation of the CPAC scheme and the DTVC scheme was carried out, respectively, and the Monte Carlo random test method was introduced to conduct the statistical test of the landing accuracy. The simulation results show that the DTVC scheme improves the landing accuracy and speed compared to the CAPC scheme and decouples the position control loop from the attitude control loop, finally enabling the UAV to complete the flight control in the VTOL phase.

A Study of Suspension Geometry for Personal Mobility Vehicles (PMVs) with Inward Tilt Mechanism

A Study of Suspension Geometry for Personal Mobility Vehicles (PMVs) with Inward Tilt Mechanism

Modeling and simulation of the kinematic behavior of the deployment mechanism of solar array for a 1‐U CubeSat

AbstractKinematics of deployable solar array mechanisms in CubeSat satellites have considerable influence on the stability and attitude control of a satellite, especially in low mass systems as CubeSats. One of the issues with the conventional solar panel deployment mechanisms in CubeSats is the speed of its deployment, especially when position‐lock to hold the panels back from oscillation is lacking. The generated oscillation becomes more pronounced in a system equipped with solar tracking unit and thus, reduces available projected area of the panels and causing fatigue at the yoke and panel hinges. This work aims at modeling and simulation of the 1‐U CubeSat solar panel deployment mechanism vibration control using fisher wire. Two‐fold panel deployment mechanism with a rolling sun‐tracking tilt mechanism was developed. The system performance from viewpoint of vibration analysis was evaluated using mass‐spring‐damper method and bond graph techniques. Numerical simulations and experiments were performed to validate the proposed method. The modeling and computational analysis were done with SOLIDWORKS software. The system was tested for vibration and stability using the seismic mass‐spring‐and‐damper arrangement to validate the model. A 3‐D printing was generated and tested to evaluate its vibration performance and its effects during deployment. The result was such that the two panels attached to a wing hinged at Y – and – Y directions deployed slowly and smoothly at approximately 2 s, giving room for the vibration to decay exponentially towards zero. This agrees with reported works where a DC motor was used to control speed of deployment by increasing time to 6.8 s. The simulated and experimental results of the printed model showed close agreement with the theoretical values with an error of 0.03% in energy supply reliability and up to 400% power generation potential when compared to body mounted solar panels with the same satellite specification without a significant impact on system strength and stability.

QUaRTM: A Quadcopter with Unactuated Rotor Tilting Mechanism capable of faster, more agile, and more efficient flight.

We present QUaRTM - a novel quadcopter design capable of tilting the propellers into the forward flight direction, which reduces the drag area and therefore allows for faster, more agile, and more efficient flight. The vehicle can morph between two configurations in mid-air, including the untilted configuration and the tilted configuration. The vehicle in the untilted configuration has a higher pitch torque capacity and a smaller vertical dimension. The vehicle in the tilted configuration has a lower drag area, leading to a higher top speed, higher agility at high speed, and better flight efficiency. The morphing is accomplished without any additional actuators beyond the four motors of a quadcopter. The rigid connections between the quadcopter frame and the quadcopter arms are replaced with sprung hinges. This allows the propellers to be tilted when high thrusts are produced, and recover to the untilted configuration when the thrusts are brought low. The effectiveness of such a vehicle is demonstrated by running experiments on a prototype vehicle with a shape similar to a regular quadcopter. Through the use of tilting, the vehicle is shown to have a 12.5% higher maximum speed, better high-speed agility as the maximum crash-free cruise speed increased by 7.5%, and a better flight efficiency as the power consumption has dropped by more than 20% in the speed range of 15-20ms-1.

The Impact of Chair Design on Trunk Sway Parameters During Computer-Based Tasks Over a Prolonged Bout of Sitting

Prolonged sedentary behavior has increased due to computer use for work and leisure activities. Prolonged bouts of sitting have been associated with health risks such as low back pain. Prior studies have suggested that chair design characteristics, such as the presence of arm or back rests, are associated with sitting posture, movement patterns, and low back pain. The purpose of this within-subjects study was to examine the effects of armrest adjustments and tilt mechanisms on user-chair interfacial pressure variables and micromotion while performing computer tasks. Preliminary findings indicate that proper armrest adjustments increased average displacement and in-chair movements (p < 0.04) which may reduce low back pain while sitting. Further research is needed to understand the temporality of these relationships over long bouts of sitting.

A comparative techno-economic assessment of manually adjustable tilt mechanisms and automatic solar trackers for behind-the-meter PV applications

Many studies in the literature aim to increase the amount of solar radiation falling on photovoltaic (PV) panel surface to improve its performance. Most of these studies concentrate on solar tracking systems and few studies focus on manually adjustable tilt mechanisms. However, no studies in the literature compare these two methods techno-economically. Therefore, as its main contribution, this study makes a techno-economic comparison of solar trackers and manually adjustable tilt mechanisms. First, the electricity production of fixed-tilt, manually adjustable tilt mechanisms (monthly and seasonal adjustment), and automatic solar trackers (single-axis east-west (SA-EWT), single-axis south-north (SA-SNT), and dual-axis (DAT)) systems are technically analyzed for three provinces in Turkey with different solar characteristics. After that, the systems are compared economically and evaluated over levelized cost of electricity (LCoE), discounted payback period (DPBP), and internal rate of return (IRR). Finally, a detailed sensitivity analysis is made and the impact of changes in initial investment costs and real interest rates is examined. Eventually, the payback period of fixed-tilt systems is found to be 10.3–13.3 years in Turkey. Dual-axis solar trackers provide the highest electricity production increase (30.4–34.6%) compared to fixed-tilt but with the highest payback period (16.7–24 years) among all alternatives. Monthly manual tilt adjustment provides the most feasible solution by decreasing the payback period of fixed-tilt systems by around 8 months to 9.6–12.6 years and with an electricity production increase of 3.6–5%.

Research on the Decoupling of the Parallel Vehicle Tilting and Steering Mechanism

Active tilting vehicles tilt to the inside of the corner when the vehicle is steering. The tilting motion improves the steering and roll stability of the vehicle. The steering mechanism and the tilting mechanism of the vehicle are connected in parallel. The transmission of the steering mechanism is influenced by the movements of the tilting mechanism. In order to solve this problem, a parallel mechanism is proposed in this paper. It consists of a spatial steering mechanism and a tilting mechanism in parallel. A mathematical model of the parallel mechanism with the wheel alignment parameters has been established. The model calculates the decoupling conditions of the parallel mechanism. In this study, a decoupling method for the parallel mechanism is proposed. A prototype of the parallel mechanism was designed according to the proposed method. The prototype was found to reduce the influence of vehicle tilting on the outer and inner wheel steering angles by up to 0.64% and 0.78%, respectively. The steering geometry correction rate of the prototype is between 1.198 and 0.961. The correctness of the model was verified by experimentation on the prototype. The proposed method can effectively decouple the tilting motion and steering motion of the vehicle and make the wheels on both sides satisfy the Ackerman steering condition.

A three-wheeled vehicle for the disabled people

This article presents the construction of a prototype three-wheeled vehicle for people with disabilities, approved in the L2e category. The vehicle is equipped with a special tilt mechanism that allows people with disabilities, who cannot balance their body, to return to an upright position after completing a driving maneuver on a curve of the road. The tilt angle of the vehicle depends on its speed and steering angle. When designing the vehicle, the availability and price of spare parts for scooters and motorcycles were taken into account to make the vehicle as cheap as possible.

Design of a Novel Long-Reach Cable-Driven Hyper-Redundant Snake-like Manipulator for Inspection and Maintenance

Robotic inspection and maintenance are gaining importance due to the number of different scenarios in which robots can operate. The use of robotic systems to accomplish such tasks has deep implications in terms of safety for human workers and can significantly extend the life of infrastructures and industrial facilities. In this context, long-reach cable-driven hyper-redundant robots can be employed to inspect areas that are difficult to reach and hazardous environments such as tanks and vessels. This paper presents a novel long-reach cable-driven hyper-redundant robot called SLIM (Snake-Like manipulator for Inspection and Maintenance). SLIM consists of a robotic arm, a pan and tilt mechanism as end-effector, and an actuation box that can rotate and around which the arm can wrap. The robot has a total of 15 degrees of freedom and, therefore, for the task of positioning the tool centre point in a bi-dimensional Cartesian space with a specific attitude, it has 10 degrees of redundancy. The robot is designed to operate in harsh environments and high temperatures and can deploy itself up to about 4.8 m. This paper presents the requirements that drove the design of the robot, the main aspects of the mechanical and electronic systems, the control strategy, and the results of preliminary experimental tests performed with a physical prototype to evaluate the robot performances.

Techno-economic analysis of PV systems with manually adjustable tilt mechanisms

Solar radiation falling on photovoltaic (PV) panel surface can be maximized via solar tracking systems, however, in return for infeasible investments. On the other hand, manual and periodic tilt adjustment of PVs can increase energy yield significantly and cost-effectively. Therefore, this study presents a techno-economic analysis of 1 MW PV power plants with manually adjustable tilt mechanisms. Firstly, the optimal tilt angles for fixed and periodically adjusted (monthly, seasonal, and semi-annual) PV systems in locations with different solar characteristics in Turkey are estimated, and then an economic analysis is performed, including a sensitivity analysis. The results show that, manual tilt adjustment provides a remarkable net present value (NPV) increase in Turkey between 12.4 and 14.9% compared to fixed-tilt. The discounted payback period (DPBP) ranges between 9.20 and 12.36 years and can be shortened by 8–10 months. The internal rate of return (IRR) of 5.4–8.6% can be increased by 0.7–0.9%.

A Study of Steer Characteristics of Personal Mobility Vehicle (PMV) with Inward Tilting Mechanism

A Study of Steer Characteristics of Personal Mobility Vehicle (PMV) with Inward Tilting Mechanism

Cooperative Target Tracking by Multiagent Camera Sensor Networks via Gaussian Process

In this paper, we present learning-based robust cooperative control for camera sensor networks. The dynamics of each camera agent with the pan and tilt mechanism is modeled by the Euler-Lagrange equation. In the target tracking problem, the modeling errors caused by high nonlinearity of camera system dynamics and changes in the tracking environment may incur significant deterioration of tracking performance. To address this, we propose a distributed control method based on the Gaussian process regression to compensate for the model uncertainty of the dynamics of the camera sensor network. We consider the error dynamics of the multiagent Euler-Lagrange system to evaluate the tracking errors of the camera agents. We show that the ultimate boundedness of the error dynamics is achieved by the proposed learning-based method. A numerical example confirms that the proposed control law enables each camera agent to track the targets with a bounded tracking error in the presence of model uncertainty.

Криволинейные участки пути и поезда с наклоном кузова вагонов

On the railway, one of the bottlenecks in increasing the speed of trains are curved sections of track. When passing such sections by the crew, a centrifugal force arises, which is proportional to the square of the speed and inversely proportional to the radius of the circular curve. This force is partially neutralized by elevation of the outer rail in the curve. There is a so-called outstanding acceleration, the magnitude of which is limited by technical conditions. On high-speed railways, when the permissible outstanding acceleration acting on the passenger is exceeded, trains with a car body tilt are operated to neutralize this acceleration. The tilt of the body can be passive due to centrifugal forces and active with the help of special tilt mechanisms. In any case, the tilt speed should be linked to the process of passing the curved section by train. It is shown that the use of the biclotoid curve design smooths the inertia of the kinetics of the car body tilt. Biclotoid design is the design of a curved section with two transition curves butt-to-butt, without a regular circular curve. Such a design reduces the forces of interaction between the wheel and the rail, increases the smoothness of the train movement, which makes it easier to adapt the process of tilting of the body to the passage of a curved section by train. It is proposed to take into account the concept of “force impulse”. This will allow, at high speeds, to use a more technically permissible outstanding acceleration equal to 0.4 m/s2.

Towards a Clinically Optimized Tilt Mechanism for Bilateral Micromanipulation with Steady-Hand Eye Robot.

Cooperative robotic systems for vitreoretinal surgery can enable novel surgical approaches by allowing the surgeon to perform procedures with enhanced stabilization and high accuracy tool movements. This paper presents the optimization and design of a four-bar linkage type tilt mechanism for a novel Steady-Hand Eye Robot (SHER) which can be used equivalently on both, the left and right patient side, during a bilateral approach with two robots. In this optimization, it is desirable to limit the workspace needed for compensation motions that ensure a virtual remote center of motion (V-RCM). The safety space around the patient, the space for the surgeon's hand and maintaining positional accuracy are also included in the optimization. The applicability of the resulting optimized mechanism was confirmed with a design prototype in a representative mock-up of the surgical setting allowing multiple directions of robot approach towards a medical phantom.

Nontopological chiral chemical potential due to the Zeeman field in magnetic Weyl semimetals

As condensed-matter manifestations of the chiral anomaly, the coexistence of positive longitudinal magnetoconductivity (LMC) and the planar Hall effect (PHE) is regarded as a characteristic transport signal for the Weyl semimetal (WSM) phase. By including a finite Newtonian mass into the general linearized WSM model, we derive an analytical expression for the chiral chemical potential, which includes a topological term of the chiral anomaly and a nontopological term. The nontopological term stems from the Zeeman-field-induced tilt of the Weyl cones, which breaks the symmetry of the fermion filling between the Weyl valleys of opposite chiralities and further leads to a chiral chemical potential $\ensuremath{\propto}\mathbit{E}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbit{B}$, much as the effect of the chiral anomaly. We demonstrate that the resulting LMC is positive and can coexist with the PHE without invoking the mechanism of the chiral anomaly. Hence, the chiral chemical potential might not be exclusively respected to the chiral anomaly. Experimentally, one can distinguish the chiral anomaly from the proposed tilt mechanism by inspecting the dependence of magnetoconductivity on the Fermi energy.