Carriage Position Research Articles

Passenger Service Satisfaction Evaluation of Jakarta-Bandung High-Speed Railway

As competition in the passenger transportation industry intensifies, high-speed railway must continuously improve service quality to win passenger satisfaction and secure a place in the competitive market. The Jakarta- Bandung High-Speed Railway (JBHSR), Indonesia’s and Southeast Asia’s first high-speed rail, commenced operation in October 2023. This study aims to identify areas for service improvement by measuring and evaluating passenger satisfaction and proposing optimization suggestions. Combining domestic and international service quality evaluation schemes and customer satisfaction models, this study employs the Analytic Hierarchy Process (AHP) to construct a passenger satisfaction evaluation system for high-speed rail services from three dimensions: perceived quality, expected value, and perceived value. A passenger satisfaction survey was conducted, and the results were analyzed using AHP and Fuzzy Comprehensive Evaluation (FCE) methods to calculate satisfaction scores. The Importance-Performance Analysis (IPA) revealed that aspects such as ease of ticket purchasing, accuracy of train operation information, and punctuality scored highly in terms of satisfaction. However, items categorized under ‘Concentrate Here’ and ‘Low Priority’ quadrants require further optimization. This study benchmarks successful practices from other countries’ HSR systems and proposes specific improvement measures, including installing free Wi-Fi at stations and on trains, expanding parking capacity with an online reservation system, increasing the number of escalators and elevators at Padalarang Station, and installing electronic displays and enhancing ground signage for better visibility of carriage positions. These measures aim to improve the quality of HSR services and enhance passenger satisfaction.

Design, Development and Commissioning of the Boldrewood Towing Tank – A Decade of Endeavour

The process of design, build and eventual commissioning of the towing tank on the Boldrewood Innovation Campus is described. The design brief required a facility that would have a capability to test models at a commercial scale but that would be effective as teaching environment for the next generation of Naval Architects as well as providing a flexible space for future fundamental research. Each of these provided their own challenges but the eventual solution of a 138 m long, 3.5 m deep, 6 m wide facility has more than met the initial aspirations. Equipped with 12 independent 0.5 m wavemaking flaps at the West end, a passive beach at the East end, a deployable side beach along the South wall for post run wave absorption and a monocoque Aluminium alloy carriage, the Boldrewood towing tank has now been successfully operating for more than a year. The carriage position and speed are controlled by a twin winch arrangement using a laser positioning system and low embodied energy composite cables. The carriage can reach a maximum speed of 10 m/s with controllable acceleration rates and can have up to four constant speed phases per run. Initial commissioning results and comparisons with benchmark data for the KCS hull confirm the accuracy and repeatability of the facility. In particular, the position and speed of the carriage are known to a high level of precision. To date research and consultancy work has spanned the performance of high speed vessels, uncrewed underwater and surface vessels, wave energy and tidal current systems, floating platforms for wind turbines, performance sport work for sailing, kayaking, rowing and swimming, open water propeller tests as well as conventional displacement vessel testing for self-propulsion and resistance. All ship science and maritime engineering students use the facility as part of their taught modules in every year of their programme as well as for individual, MSc and group projects as appropriate. It has also made a strong impact on the many thousands of visitors a year to the campus for science and engineering open days.

Method of Failure Diagnostics to Linear Rolling Guides in Handling Machines.

Linear rolling guides, used in production machines for the realisation of linear motion, demand in industrial practice early damage identification to prevent production outages and losses. Therefore, the article aims for early damage diagnostics that use the principle of a load-free diagnostic part integrated into the carriage of the linear rolling guide. This principle was employed for developing an innovative method of damage identification to a guiding profile or rolling elements. The proposed innovative method is based on analysing vibration acceleration measured on the diagnostic part in the context of carriage position. In addition, a unique connection of an acceleration sensor to the diagnostic part through a mechanical component with defined parameters of stiffness and mass was designed. The innovative method was verified by laboratory testing on a designed functional sample of the diagnostic system. The computed reliability of the proposed diagnostic method reached 98%.

Synthesis of the Energy-Saving Dry Dual Clutch Control Mechanism

A promising direction in developing up-to-date transport vehicles is the use of transmissions, an essential element of which is a dual-clutch. Improving functional performance, energy efficiency, and environmental friendliness are relevant and require appropriate research. The object of study is a dry dual-clutch working with a manual transmission with high energy efficiency. In the proposed design scheme, a rotary lever and a movable carriage can change the structural diagram of the force interaction between the pressure spring and the clutch discs. The developed mathematical model of the clutches control mechanism allowed for analyzing the process of controlling the dual-clutch transmissions (DCT) and obtaining functional dependencies between pushing forces in friction pairs and the carriage position. As a result, a method for synthesizing DCT was proposed to ensure the transmission of a given torque. Furthermore, it was determined and numerically proven that the same radial movement of the carriage when switching-on the clutches does not guarantee equal loading for the frictional discs of each clutch. This fact increases the uneven dynamics of torque and disc wear. Overall, the synthesis of the energy-saving dry dual-clutch control mechanism providing the same clutch margin for each clutch was developed. The method can be generalized and applied to designing dry dual-clutch transmissions for machines of various purposes.

APPROACH METHOD FOR FLEXIBLE REALLOCATION OF RESERVED SEATS ON LONG - DISTANCE TRAINS

Finding a reserved seat on long-distance train travel is supported by aids on platforms and within the train in order to keep the passenger’s journey as short as possible and to minimise unnecessary walking within the train. The allocation of a seat to a carriage number on the reservation and the consideration of the carriage position indicator devices on the platform provide the opportunity to wait for the arrival of the train on a section of the platform that is close to the reserved seat. Nevertheless, there are various situations in reality in which this can only be achieved to a limited extent. Varying carriage order, the provision of a replacement train or tight transfer connection can lead to the train being entered at an unfavourable position. This is followed by the passenger trying to find a seat on the train which can amount to considerable traffic. Equipped with a flexible seat reservation procedure, this kind of traffic could be drastically reduced. The solution provides the opportunity to reallocate reserved seats in order to minimize the way a passenger has to walk inside the train to his seat. By means of microscopic simulations, various boarding scenarios demonstrate the effectiveness of this approach. Less passenger movement on the train results in an increase in passenger comfort and reduces the space that is required for such movement, which could instead be used for other purposes. On the platform, this procedure means that passengers no longer need to wait for the arrival of the train at a location that is closest to the allocated seat. Instead, passengers can choose a place on the platform convenient to them, without this having a disruptive effect on system performance.

Hybrid model for the analysis of the modal properties of a ball screw vibration system

In accordance with the vibration characteristics of ball screw feed systems, a hybrid modeling method is proposed to study its dynamic behavior. Partially, the ball screw is modeled as a continuous body, and the remaining components are considered lumped masses, allowing for a realistic description of the dynamics of the feed system. The axial, torsional, transverse, and bending vibration models of a ball screw carriage system are established via the Rayleigh-Ritz series method based on the Timoshenko beam assumption. The established model that added the Timoshenko beam assumption obtains the coupling vibration displacement between the transverse and bending vibrations of the lead screw, which is close to real situations. Numerical simulations are conducted to investigate the changes of the natural frequency and modal shapes of ball screw systems with carriage positions. Results show that the carriage position has significant influence on the amplitude and direction of axial and transverse vibrations, substantial influence on the direction of the bending vibration, and minimal influence on the amplitude and direction of torsional vibration. These results indicate that the proposed hybrid model performs well to predict the vibration characteristics of the feed system. Moreover, the carriage position and carriage load also have a remarkable effect on the frequency response of the feed system. These results, along with the modeling approach, provide an important basis for the further study of in-machining monitoring and vibration controller design.

Skyline tensile force monitoring of mobile tower yarders operating in the Italian Alps

This study analysed the skyline tensile forces in 502 complete work cycles during ordinary cable logging operations on 12 different cable lines in the Italian Alps. The objectives of the research were to quantify the frequency of exceeding the recommended safe working limits and to determine the skyline peak tensile forces and dynamic amplifications, as well as their explanatory variables. Data collection was based on skyline tensile force monitoring synchronized with the video recording of the logging operations and the monitoring of the carriage positions. The load volumes were measured at the landing, and the total loads were estimated for each cycle. The results showed 55% of the work cycles exceeding the safe working load. The highest peak tensile forces were often recorded while starting the load moving during lateral skid. High-peak tensile forces were also recorded during inhaul, where the tensile forces were amplified by the cyclic load behaviour. It appears that some operators underestimate the effects of pretension, payload, and cable line geometry on the magnitude of the skyline tensile force. The complexity in identifying reliable theoretical models inclusive of dynamic amplifications and the inefficacy of the load limiters installed on the machines highlighted the need to improve the best practices within the operators, and to adopt technical solutions for the continuous skyline tensile force monitoring during ordinary cable logging operations.

The study of the control law for carriage positioning of rodless pneumatic actuator with fuzzy regulator

The study of the control law for carriage positioning of rodless pneumatic actuator with fuzzy regulator

Aeroelastic simulations of stores in weapon bays using Detached-Eddy Simulation

Detached-Eddy Simulations of flows in weapon bays with a generic store at different positions in the cavity and with flexible fins are presented in this paper. Simulations were carried out to better understand the fluid–structure interactions of the unsteady, turbulent flow and the store. Mach and Reynolds numbers (based on the missile diameter) were 0.85 and 326.000 respectively. Spectral analysis showed few differences in the frequency content in the cavity between the store with rigid and flexible fins. However, a large effect of the store position was seen. When the store was placed inside the cavity, the noise reduction reached 7dB close to the cavity ceiling. The closer the store to the carriage position, the more coherent and quieter was the cavity. To perform a more realistic simulation, a gap of 0.3% of the store diameter was introduced between the fin root and the body of the store. Store loads showed little differences between the rigid and flexible fins when the store was inside and outside the cavity. With the store at the shear layer, the flexible fins were seen to have a reduction in loads with large fluctuations in position about a mean. Fin-tip displacements of the store inside the cavity were of the range of 0.2% of the store diameter, and in the range of 1–2% of store diameter when at the shear layer.

Vertical Integration, Regional Concentration, and Availability in Cable Programming Networks

Using a 2009 cross-sectional database of digital cable systems in the United States, this study examines the combined effects of vertical integration and regional concentration (cable TV clusters) on the carriage and tier positioning of cable networks. Focusing on four basic cable network segments—the outdoor, cartoon, movie, and Comcast affiliated networks—this study finds that vertical integration has reduced program availability for cable subscribers by increasing their access to integrated networks and by limiting their access to unaffiliated networks. It also finds that an increase in the regional concentration of cable systems positively affects the availability of overall basic cable networks, regardless of vertical ownership. An increase in regional concentration is also associated with a decrease in the effects of vertical integration, suggesting that system efficiency through regional concentration may mitigate the vertical integration effect.

High Performance Machining Enabled by Adaptive Machine Components

Abstract A current drawback in high performance machining is the dynamic behavior of the machine tool. The dedicated Eigenfrequencies of the machine tool structure lead to not optimal cutting parameters due to the danger of chatter. Possibilities to overcome this drawback are on one hand the unwanted variation of the cutting parameters and on the other hand the variation of the dynamic properties of the machine tool components. The variation of the dynamic properties of these components requires high efforts and expenses. An approach to easily vary the dynamic characteristic of the machine tool is a carriage made out of Carbon Fibre Reinforced Plastic (CFRP) with adequate mass shifting by filling the built in chambers with a fluid. This leads to shifted Eigenfrequencies and therefore to optimal cutting parameters without chatter. The mass ratio between the empty lightweight machine tool carriage made out of CFRP and the one filled enables a significant frequency shift. Within this paper three issues will be addressed: first the frequency shift depending on the carriage's position will be examined, the frequency shift according to the filling strategy will be shown and finally the amplitude reduction related to the external excitation will be presented.

Analysis of chip formation mechanisms and modelling of slabber process

During the primary transformation in wood industry, logs are faced with conical rough milling cutters commonly named slabber or canter heads. Chips produced consist of raw materials for pulp paper and particleboard industries. The process efficiency of these industries partly comes from particle size distribution. However, chips formation is greatly dependent on milling conditions and material variability. Thus, this study aims at better understanding and predicting chips production in wood milling. The different mechanisms of their formation were studied through orthogonal cutting experiments at high cutting speed for beech and Douglas fir. Under these conditions, ejection of free water inside wood can be observed during fragmentation, particularly on beech. As previously seen in quasi-static experiments, chip thickness is proportional to the nominal cut thickness. Moreover, the grain orientation has a great influence on the cutting mechanisms, so as the nominal cut and the growth ring widths. This chip fragmentation study finally allows the improvement of the cutting conditions in rough milling. In order to optimize machine design as well as cutting geometry, a geometrical model of a generic slabber head was developed. This model allows the study of the effective cutting kinematics, the log-cutting edges interactions and the effective wood grain direction during cutting. This paper describes the great influence of the carriage position on cutting conditions. The results obtained here can be directly used by milling machine manufacturers.

Comparison of Model-Based Approaches to the Compensation of Hysteresis in the Force Characteristic of Pneumatic Muscles

In this paper, a comparison of three different feedforward compensation strategies that counteract hysteresis effects in the nonlinear force characteristic of pneumatic muscles is presented: The generalized Bouc-Wen model is a dynamic hysteresis model and enables a description of the given highly asymmetric hysteresis, and as alternative hysteresis models for the comparison, the quasi-static Maxwell-slip model and the Prandtl-Ishlinskii model are considered. The parameters of all these hysteresis models have been experimentally identified using evolutionary optimization algorithms. Each of the identified hysteresis models is suitable for an additional feedforward control action in an existing nonlinear control structure for a high-speed linear axis that is actuated by pneumatic muscles to further reduce the tracking error. This cascaded nonlinear control structure consists of fast underlying control loops for the internal muscle pressures and an outer adaptive backstepping control loop for both the carriage position and the mean muscle pressure. Here, the adaptive control part counteracts nonlinear friction and the remaining model uncertainty. Comprehensive experimental results from an implementation of the proposed control approach on a test rig at the Chair of Mechatronics, University of Rostock, Rostock, Germany, point out both the benefits and efficiency of the corresponding feedforward hysteresis compensation strategies.

SU‐E‐T‐282: Remove Field‐Size Limitation Using the Combination of Collimator Rotation and Jaw Tracking with MLC Aperture

Purpose:this study is to investigate the use of variable‐collimators and/or collimator‐rotation to overcome the field‐size limitation on TrueBeamSTX.Methods:The maximum static field‐size is 22‐ × 40‐cm for TrueBeamSTX and 40‐ × 40‐cm for Trilogy. Maximum displacement between adjacent leaf ends at a single carriage position is 15‐cm for TBSTX and 14‐cm for Trilogy. Our current practice for IMRT treatment at Trilogy is as follows, if MLC leaves travel more than 13.5 cm in the MLC traveling direction, the treatment fields will be split at isocenter to two groups of IMRT fields to cover the large tumors. However, TrueBeamSTX is not limited in this way because the jaws can track each segments of the MLC aperture. Radiation treatment plans for ten patients (different tumor sites) treated at Trilogy with one dimension of the field is greater than 22 cm and the other dimension is less than or equal to 22 cm. All the plans will be converted with jaws tracking each segment's MLC aperture. If necessary, the collimator rotation will also be applied for the planning. Comparison of the converted plans with the original clinical plans will be evaluated and based on the following criterion: (1) tumor coverage; (2) dose sparing to the critical structures; and (3) treatment time.Results:The tumor coverage is compatible between two plans. The dose of critical structures was evaluated in the cumulative DVH for spinal cord, parotids, and brainstem at V20 and V5. In all patients, the maximum reduction in V20 was never more than 5% and was typically less than 1%. In V5, the maximum reduction was 10% and 3% respectively. The significant difference can be found in using the variable collimator to shorten the treatment time.Conclusion:We conclude that we will use the variable‐collimator for all IMRT cases on TrueBeamSTX and as a potential backup machine for Trilogy.

An exploration of load accommodation strategies during walking with extremity-carried weights

The strategies used by individuals to respond to loading perturbations have implications for both musculoskeletal health and statistical data analysis. The purpose was to explore load accommodation strategies during walking with extremity weights carried in different positions. Twenty subjects walked on an instrumented treadmill while carrying 0, 44.5 and 89N at the wrists and ankles. Peak ground reaction force (GRF) during weight acceptance was extracted for analysis. The change in peak GRF due to the addition of weight was calculated and used to quantify strategies. Results indicated that on average GRF increased (p<.05) more than the increase in weight alone in two of three load carriage positions, and ranged from 0.95 to 1.45N/N. The strategy for weights carried at the wrists with the arms unconstrained (M±SD, 1.06±.42N/N) was significantly (p<.017) less than with the wrists constrained (1.35±.56N/N) or with weights carried at the ankles (1.40±.72N/N). Individuals exhibited a range of strategies from greatly increasing to slightly decreasing GRF with the addition of weight. Ninety-six percent of strategies resulted in GRF increases. Subject strategies may affect tissue loading and their presence decreases the validity of group statistical analyses.

Interferometric system with tracking refractometry capability in the measuring axis

We present a combined interferometric arrangement designed for measurement of one-axis displacement over a specified measuring range with mechanical referencing. This concept allows simultaneous measurement of the carriage position from both sides together with monitoring of the overall range. This can be used in configuration with in-line monitoring of the fluctuations of the refractive index-–tracking refractometry. Similarly, the wavelength of the laser source can be stabilized over the measuring range, effectively compensating for the refractive index changes. Otherwise, monitoring of length of the measuring range can give information about the thermal dilatation effects of frame of the whole measuring setup. This technique can find its way into high-precision positioning systems in nanometrology.

Experiments on level ice loading on an icebreaking tanker with different ice drift angles

Abstract A series of tests was performed with a laboratory-scale model ship to simulate the effects of ice load parameters on an icebreaking tanker. A model of the icebreaking tanker Uikku was mounted on a rigid carriage and towed through an unbroken ice sheet in the ice tank of the Marine Technology Group at Aalto University. Two ice sheets and 11 different experimental configurations were used. The carriage speed, heading angle of the model ship, and ice thickness were varied, and the forces, accelerations, ice cusp sizes, carriage positions, and ice pile dimensions under the intact ice sheets were measured. This paper includes results for the measurements of ice rubble loads against the model hull in the horizontal plane. Phenomena such as ice failure modes and ice rubble accumulation on the upstream side of the hull beneath the ice sheet were observed in some tests. The icebreaking lengths and dimensions of ice rubble were analyzed for some tests. The effects of towing speed, heading angle under the intact ice sheet in front of the hull, and the accompanying ice loads on the formation and build-up of ice rubble were analyzed. In addition, the evolution of ice rubble geometry, in cross sections and the horizontal plane, was investigated. There was good agreement over several orders of magnitude between the measured and calculated values of the lateral ice forces. These results are relevant to the modeling of ice loading on hulls and the design of moored or dynamic positioned structures for operation in ice-covered waters. Some parameters obtained from these tests can be used as input for future numerical simulations.

Space Positioning of the 5-DOF Robotic Excavator

The carriage positioning of excavator in three-dimensions (3-D) is the precondition of the robotic excavator starting roboticized works. In order to get the carriage position of excavator in three-dimensional space, angle sensors of such joints as bucket, arm, boom, and boom deflection are brought to bear. At the same time, a 2D-inclination sensor is introduced to check the list and pitch angles of the platform, and a rotatory angle sensor is introduced to check swing angle of the platform. And a laser receiver was mounted on the arm to measure the relative height of the arm to the laser beam from ground sender. Then the kinematic model is established, the coordinate transformation matrix of carriage positioning is formulated, and the height of the body relative to the ground is gotten. As a result, the coordinate transformation matrix of the bucket relative to the ground and the digging depth are formulated. That makes the excavator orient bucket precisely and set excavation depth exactly, and make automotive elaborate excavation come true.

Modeling and vibration mode analysis of a ball screw drive

Positioning systems for machine tools are generally driven by ball screws due to their high stiffness and low sensitivity to external perturbations. However, as modern machine tools increase their velocity and acceleration of positioning, the resonant modes of these systems could be excited degrading the trajectory tracking accuracy. Therefore, a dynamic model including the vibration modes is required for machine design as well as for controller selection and tuning. This work presents a high-frequency dynamic model of a ball screw drive. The analytical formulation follows a comprehensive approach, where the screw is modeled as a continuous subsystem, using Ritz series approximation to obtain an approximate N-degree-of-freedom model. Based on this model, the axial and angular components of each mode function are studied for different transmission ratios to determine the degree of coupling between them. After that, the frequency variation of each mode was studied for different carriage positions and different moving masses. Finally, an analysis of these results applied to controller design and parameter estimation is also presented.

Finite Element Modeling and Tansfer Function Prediction of Ball-Screw Drive System

The closed-loop performance of a ball-screw drive is usually limited by a resonance in which the carriage oscillates in the direction of motion as the screw undergoes longitudinal and torsional deformation. By means of the finite element method (FEM), a model of ball-screw system dynamics is presented by taking into account the distributed inertia of the screw and the compliance and damping of thrust bearings, nut and coupling. Transmission ratio is modeled using DOFs (degree of freedoms) constraint equation. The model is found to accurately predict the transfer function from motor torque to carriage position. Comparing the predicted responses with experiments performed on a pair of ball-screw drives, the resonance frequency is misestimated as much as 5% in the worst case.