Using a low-cost bluetooth torque sensor for vehicle jerk and transient torque measurement

© IMechE 2019. This paper presents the use and development of a specific wireless torque measurement system that is used to obtain the transient torque performance of vehicle transmissions. The torque sensor is strain-based, using surface-mounted strain gauges on a prop shaft. The gauges are connected to a compact printed circuit board, which is clamped to the shaft next to the strain gauges using a three-dimensional printed housing. The printed circuit board contains an amplifier, low-pass filter, analog-to-digital converter, microcontroller and bluetooth transceiver. The printed housing is impact resistant carbon-reinforced nylon and securely retains the printed circuit board and the battery powering the device. The transmitted torque data are received by a transceiver, which is interfaced to a PC through an RS-232 connection. NI LabVIEW is used to process, display and save data. The wireless torque sensor was installed to the Unit Under Test at the output shaft of the five-speed manual transmission. The Unit Under Test was installed on a dynamometer for verification purposes and the transient torque was recorded under various operational conditions. The transient output torque of the manual transmission is measured and compared with results obtained from simulations performed under similar operating conditions. The two sets of transient responses show a good correlation with each other and hence demonstrate that the torque sensor meets the major design specifications. The data obtained will be used to enhance the fidelity of the software model

Study of drag torque in a two-speed dual clutch transmission electric vehicle powertrain system

University of Technology, Sydney. Faculty of Engineering and Information Technology.Pure electric vehicles are widely looked as a potential avenue to reduce fossil fuel consumption and emission in the long term in the transportation section. Pure electric vehicles currently being used in the market are mainly equipped with single speed transmissions, with tradeoffs between dynamic (such as climbing ability, top speed, and acceleration) and economic performance (drive range). The employment of two-speed dual clutch transmission (DCT) in electric vehicles is likely to improve average motor efficiency and range, and even can reduce the required motor size. In order to comprehensively improve the electric vehicle powertrain system efficiency, it is necessary to fully consider the proposed two-speed transmission drag torque, including its influences and potential applications. The focus of this thesis is on studying the drag torque within two-speed dual clutch transmissions. Different source of drag torque in the DCT are theoretically analysed and modelled, including torsional resistance caused by viscous shear caused between wet clutch plates and concentrically aligned shafts, gear mesh friction and windage, oil churning, and bearing losses. Then experimental works are carried out on UTS electric vehicle powertrain system test rig. Outcomes of experimentation on drag torque confirm that simulation results agree well with the test data. Then, based on the drag torque study, the thermal behaviour of the transmission is analysed via both theoretical and experimental investigation. Finally, integrated optimal design of electric vehicle powertrain system equipped with two-speed DCT is performed, considering drag torque, shift schedule, electric motor selection, gear ratio design and wet clutch design

Wireless Sensor Integrated Tool for Characterization of Machining Dynamics in Milling

A first step towards practical sensing in the machining environment is the development and use of low cost, reliable sensors. Historically, the ability to record in-process data at an end mill tool tip has been limited by the sensor location. Often, these sensors are mounted on the material workpiece or the machine spindle at significant physical distance from the cutting process. Of specific interest are the problems of tool chatter which causes limitations to productivity and part quality. Although tool chatter is a substantial issue in machining, it remains an open research topic. In this research, a sensor integrated cutting tool holder is developed to specifically analyze the problems related to tool chatter. With the sensor integrated cutting tool holder, the signal to noise ratio is higher than traditional sensing methods. Because of the higher sensitivity, new data analysis methods can be explored. Specifically, the sensor is used in conjunction with a data dependent linear predictive coding algorithm to demonstrate effective prediction of chatter frequencies from stable cutting

Kinematic and neuromuscular measures of intensity during drop jumps in female volleyball players

The aim of this study was to assess drop jump (DJ) performance variables (jump height, contact time, and reactive strength index) concomitant to surface electromyography (sEMG) of lower limb muscles during DJs from different drop heights (intensities). The eccentric and concentric phase sEMG from the gastrocnemius medialis, biceps femoris, and vastus medialis muscles were assessed during all tests, with sEMG activity normalized to maximal voluntary isometric contraction (MVIC). In a cross-sectional, study, 10 amateur female volleyball players (age 22.1 ± 1.8 years; body mass 72.9 ± 15.2 kg; height 1.70 ± 0.08 m) completed DJs from six heights [15-90 cm (DJ15 to DJ90)]. During DJs there was no jump-target box to rebound on to. Results of one-way analysis of variance (ANOVA) showed that the jump height, contact time, and reactive strength index were not significantly ( \u3e 0.05) different between drop heights. Mean biceps femoris eccentric and concentric sEMG ranged from 27 to 50%, although without significant differences between drop heights. Mean gastrocnemius medialis eccentric and concentric sEMG remained relatively constant (∼60-80% MVIC) across DJs heights, although eccentric values reached 90-120% MVIC from DJ75 to DJ90. Mean variations of ∼50-100% MVIC for eccentric and ∼50-70% MVIC for concentric sEMG activations were observed in the vastus medialis across DJs heights. The biceps femoris eccentric/concentric sEMG ratio during DJ45 (i.e., 1.0) was lower ( = 0.03) compared to the ratio observed after DJ90 (i.e., 3.2). The gastrocnemius medialis and vastus medialis eccentric/concentric sEMG ratio were not significantly different between drop heights. In conclusion, jumping performance and most neuromuscular markers were not sensitive to DJ height (intensity) in amateur female volleyball athletes

Theoretical and experimental investigation of the thermal behaviour of a two-speed dual clutch transmission

Copyright © 2018 Inderscience Enterprises Ltd. Understanding the heating behaviour of automotive transmissions in an important step in prototype development, it plays a significant role in achieving appropriate tolerances at the design phase and strongly influences the system’s durability in the long term. Furthermore, lubricant viscosity is strongly dependent on operating temperature, understanding this behaviour will provide insight into how transmission efficiency is affected during vehicle warm-up. In this paper, an experimental and simulation based study has been conducted to investigate the thermal behaviour of a two-speed dual clutch transmission (DCT) that has been developed for electric vehicle applications. This is achieved through the modelling of the power losses in the system that is then integrated with a compact thermal model of the transmission. Transient heating simulations for the transmission are conducted at constant speeds and compared with experimental studies, showing a strong correlation between results. Simulations are then utilised to investigate the load and speed dependencies of the transmission’s thermal behaviour

Aerodynamic and thermal modelling of disc brakes - Challenges and limitations

The brake system is a critical component for any passenger vehicle as its task is to convert the kinetic and potential energy of the vehicle into heat, allowing the vehicle to stop. Heat energy generated must be dissipated into the surroundings in order to prevent brake overheating. Traditionally, a lot of experimental testing is performed to ensure correct brake operation under all possible load scenarios. However, with the development of simulation techniques, many vehicle manufacturers today are looking into partially or completely replacing physical experiments by virtual testing. Such a transition has several substantial benefits, but simultaneously a lot of challenges and limitations need to be addressed and understood for reliable and accurate simulation results. This paper summarizes many of such challenges, discusses the effects that can and cannot be captured, and gives a broader picture of the issues faced when conducting numerical brake cooling simulations

Is instrumental compression equally effective and comfortable for physiotherapists and physiotherapy students than manual compression? A comparative cross-sectional study

The objective of this work is to compare the homogeneity of instrumental and manual compression during the simulation of a pressure release technique, measured with a dynamometer, as well as to evaluate the comparative degree of comfort by physiotherapists and physiotherapy students when performing this technique. Methods: A comparative cross-sectional study was car-ried out with physiotherapists (lecturers with clinical experience) and 4th year students of the Physiotherapy Degree at Universidad San Jorge. The amount of pressure performed and how it was maintained during 80 s with both techniques was analysed using a digital dynamometer. The degree of comfort was evaluated using a modified numeric rating scale, with higher values represent-ing a higher degree of discomfort. Results: A total of 30 subjects participated. Significant differences were found between the techniques in terms of maintaining a constant pressure level for 80 s (p = 0.043). A statistically significant difference was found between both techniques in the period from 45 to 80 s. Regarding the degree of discomfort, the value obtained from the students’ responses was 4.67 (1.35) for the manual technique and 1.93 (0.88) for the instrumental technique. In the case of physiotherapists, the comfort was 4.87 (2.13) for the manual technique and 3.33 (1.54) for the instrumental technique. Conclusion: The sustained manual compression necessary in manual pressure release techniques in the treatment of myofascial trigger points can be performed with assistive tools that guarantee a uniform compression maintained throughout the development of the technique and are more comfortable for physiotherapists