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The purpose of this paper is to present a novel dynamometer employing direct torque control (DTC) method, which has wide application prospects in the industry field.

Conventional dynamometers such as eddy dynamometers waste energy, waste water, and operate inconveniently. In this paper, a novel digital electric power dynamometer is proposed which uses a three‐phase squirrel‐cage induction machine as the loading machine. The system uses a digital signal processor named TMS320LF2407A as the controller to control the three‐phase induction machine employing an improved DTC for precise torque tracking. The power dynamometer is in generating mode, using the common‐DC‐bus to implement energy circulating or through the energy regenerating unit feeding back the networks energy. A direct‐torque‐controller dynamometer allows very fast torque responses and flexible control. The load torque is regulated conveniently and swiftly.

Simulations and experiment results show that the design of the electronic power dynamometer based on improved DTC is proper, the control is simple, and digitized and is simple to use.

The precise torque controls are the main limitations for the high‐performance power dynamometer applied. Torque ripples should be small.

Power dynamometer based on DTC is one of the novel ones worth being generalized in place of conventional dynamometers.

The new approach of a novel digital power dynamometer based on an improved DTC is introduced.

The purpose of this paper is to improve the reliability of the force measurement system by determining the reliable test range of dynamometer.

Based on the principle of leverage and moment balance, a general force distribution model is applicable in where the test point is located either inside or outside the support region of four three-component force links of dynamometer is established. After corroborating the correctness of the model through verification experiments, the boundary conditions that each three-component force link should satisfy are analyzed by considering the characteristic of the dynamometer components comprehensively. Furthermore, the reliable test range of dynamometer is determined, followed by a calibration experiment to verify its rationality.

The relationships between the reliable test range and the tested force, the bolt pre-tightening force and the bearing capacity of quartz wafers are clarified. Further, the experimental calibration results show that when the test point is within the reliable test range, the three-directional output voltage of dynamometer has excellent linearity and repeatability. The nonlinearity and repeatability in X-, Y- and Z-directions are all less than 1.1%.

A general mathematical model of force distribution of four three-component force links is constructed, which provides a theoretical basic for the mechanical analysis of multi-sensors’ dynamometer. Comprehensively considering the performance of dynamometer components, the value of measured force and the pre-tightening force, the simultaneous equations of reliable test range are deduced, which limits the boundary of allowable test position of piezoelectric dynamometer.

The purpose of this paper is to solve the problem that the relationship between loading forces, which were applied at different positions on a plane, and output values of load-sharing dynamometer is non-linear.

First, the analytical model of ISPM (isodynamic surface proportional mapping method) method, which is used to calibrate dynamometer, was established. Then, a series of axial force calibration tests were performed on a load-sharing dynamometer at different loading positions. Finally, according to output values, calibration forces at different loading positions were calculated by ISPM method, and corresponding distribution histogram of calibration force error was generated.

The largest error between calculated force and standard force is 2.92 per cent, and the probability of calculated force error within 1 per cent is 91.03 per cent, which verify that the ISPM method is reliable for non-linear calibration of dynamometers.

The proposed ISPM method can achieve non-linear calibration between measured force and output signal of load-sharing dynamometer at different positions. In addition, ISPM method can also solve some complex non-linear problems, such as prediction of plane cutting force under the influence of multiple parameters, the force measurement of multi-degree-of-freedom platform and so on.

ATTENTION has of recent months been focused upon the fact that large numbers of aero‐engines in this country are tested by means of plant which does not recover the engine power, or put it to useful work.

THE development of high‐powered aero‐engines has created a demand for dynamometers capable of dealing with powers and speeds considerably greater than were formerly possible. Whereas, a few years ago, aero‐engines of 1,000 h.p. were rarely produced, ratings of special engines have steadily crept up beyond 2,000, and will soon exceed 3,000 b.h.p. Speeds have also tended to increase considerably; and the results have been that the working stresses from torque, centrifugal forces, water velocities, etc., in the water dynamometers of existing design used for testing such engines, have approached the limit attainable with safety and reliability.

This paper aims to improve calibration and force measurement accuracy of multi-sensors’ piezoelectric dynamometer used in thrust measurement of rocket/air vehicle engine.

This paper presents a mapping solution method of sensors’ outputs based on the Kirchhoff thin plate theory, builds force-deformation differential equations with specific boundary conditions, uses finite difference (FD) method to solve the equations and analyzes outputs in offset loading forces in four-sensor square layout in main direction. The resultant force deviations calculated by the Kirchhoff theory are optimized with sequence quadratic program (SQP) method, and a calibration method of multiple loading points (MLP) based on the Kirchhoff theory is presented. Experiments of static calibration and verification are complemented to contrast the novel and single loading point (SLP) calibration method.

Experiments of static calibration and its verification show that at a loading force of 5,000N, the average resultant force deviations with MLP is 17.87N (0.35% FS) compared with single loading point method 26.45N (0.53% FS), improving calibration and measurement precision.

A novel calibration method with MLP is presented. Force distributions of multiple sensors of main direction in piezoelectric dynamometer with offset loading force are solved with the Kirchhoff theory. The resultant force deviations calculated by Kirchhoff theory are optimized with the SQP method.

The purpose of this study is to present the optimization of the design and measurement principle of a six-component force/thrust measurement stand. This study highlights some key problems found in previous studies and proposes improvements in design and measurement principles.

The numerical simulation approach is used to verify the proposed improvements. An improved design and measurement principle are proposed and to verify the proposed improvements, simulation experiments are conducted. The data obtained from simulations are analyzed through the proposed improved measurement principle. The proposed stand is capable of measuring the main thrust and other components as pitch, yaw and roll. The stand is capable of measuring the main thrust more than 50,000 N and orthogonal thrust components more than 1,000 N. Improved design of measurement stand is also capable of measuring moments in three-axis more than 150 Nm. Thrust stand consists of two main sections: front and rare. Stand consists of seven piezoelectric force sensors to measure all components of force.

The simulations experiments and basic theoretical laws of kinematics prove that the proposed design indeed improves the precision of measurement and also enhance the efficiency of design. Evaluation results show that the measurement stand designed is highly functional. Non-linearity, coupling and repeatability errors are found to be within acceptable range during numerical simulations.

This study is unique in this kind. This study identifies the key problems found in previous studies and proposes an improved design and measurement principle. This study provides evidence for the improvements to be really functional and necessary.

IT is the painful experience of all who engage in experimental work of a type to which they are not accustomed, that they may easily spend more time in rectifying faults in their equipment or technique than in producing useful data. Information on these points has, therefore, considerable value to the investigator, but the supply of such information has hitherto been scanty. One reason for this, as regards research on internal combustion engines, is that, except for Government Establishments, which are naturally uncommunicative, and Universities, whose work is mainly educational rather than experimental, there are few organisations which carry out research on a scale wide enough to amass a large body of experience. One such firm is Messrs. Ricardo & Co., Ltd., who have been engaged on work of this kind for the last fifteen years. The description in these pages of their Shoreham Laboratory, and of their experimental methods, should, therefore, be of use to many. The writers (who are on the staff or Messrs. Ricardo & Co.) realise that the requirements of experimental work vary enormously, and that methods which suit their needs may not suit the needs of others. They have endeavoured, therefore, to explain not only how things are done, but why they are done in that particular way, and thus to give their readers an insight into the factors governing the choice of method, which they can apply to their own particular problems.

THE present rapid progress in the development of internal‐combustion engines necessitates rapid and accurate testing methods, and it has been the aim of the electrical industry to produce braking equipment with which the power output can be conveniently and exactly measured. These devices are termed “Electric Dynamometers” and consist of an electric generator, the frame of which is not rigidly secured but so supported as to be able to be swung slightly about the axis of the rotor. This arrangement is no different in principle from the well‐known Prony brake, since the brake‐drum and blocks of the latter are merely replaced by the rotor and swinging frame respectively of the electric machines.

This paper aims to formulate a new metal working fluid (MWF) composition including some eco-friendly emulsifiers, corrosion inhibitor, biocide, and non- edible vegetable oil (castor oil) as the base oil. To achieve this aim, five MWFs with different hydrophilic–lipophilic balance (HLB) value as 10, 9.5, 9, 8.5 and 8 were prepared to identify the optimum HLB value that gives a highly stable oil-in-water emulsion. The performance of castor oil based MWF was evaluated using tool chip tribometer and drill dynamometer. The surface morphology of steel disc and friction pin was performed using scanning electron microscope (SEM) and 3D profilometer. The results revealed that the use of the prepared cutting fluid (E1) caused the cutting force to decrease from 500 N for dry high-speed steel sample to 280N, while the same value for a commercial cutting fluid (COM) was recorded as 340 N at drilling speed and cutting feed force as 1120 rpm and 4 mm/min., respectively.

A castor oil-based metalworking fluid was prepared using nonionic surfactants. The composition of the metalworking fluid was further optimized by adding performance-enhancing additives. The performance of castor oil based MWF was analyzed using Tool chip tribometer and Drill dynamometer. The surface morphology of steel ball and a disc was done using 3D profilometer and SEM.

Studies revealed that castor oil-based MWF having Monoethanolamine (MEA) as corrosion inhibitor was found to be highly stable. The drilling dynamometer and tool chip tribometer studies showed that castor oil-based MWF performance was comparable to that of commercial MWF.

This study aims to explore the performance of the castor oil based metalworking fluid (MWF) using tool chip tribometer and drill dynamometer.

The conventional MWFs are petroleum derives and are unsustainable. Use of non-edible plant-based oils for preparing the MWF will not only be conserved environment but also add value addition to agricultural crops.

The social Implications is aiming to decrease the environmental impact that results from the using of mineral cutting fluids.

The originality of this work is to replace the mineral oil and synthetic oil based cutting fluids with more eco-friendly alternatives one. In addition, the investigation will focus on developing functional additives required for cutting fluids which are environmentally benign.