Flexible Test Bench Research Articles

EvaSprayViti: A flexible test bench for comparative assessment of the 3D deposition efficiency of vineyard sprayers at multiple growth stages

The main approach to protect grapes against diseases involves the use of plant protection products. Understanding the quantitative amount and the distribution of these products on the vines is essential to assess the effectiveness of spray equipment and to evaluate the relationship between dosage and response when targeting pathogens. Improving the targeting of sprayers is an important lever to reduce the quantities of phytosanitary inputs applied, taking into account various cropping systems and training. For this purpose, a regularly distributed artificial canopy, adjustable in height and width was designed to mimic three grapevine growth stages for two of the most common trellised training systems encountered in France for ‘wide row vineyards’ (Royat cordon and Guyot, inter-row width 2.5 m). This artificial canopy was evaluated with the perspective of using it as a testing facility for classifying sprayers. Using a dye tracer, spray deposits were directly recovered after the rinsing of artificial leaves. A first series of experiments defined the most adapted sampling strategy in the canopy according to the crop stage, with the comparison of two contrasted sprayers. A second series of experiments compared the quantities of deposits obtained from both the artificial and a real vine, for several sprayers at a full growth stage and for one sprayer at three growth stages. Deposition patterns and mean deposits on both targets were found comparable, allowing a realistic perspective for the classification of spray application modalities using the artificial vine. A third series of experiments compared deposition at three crop stages on artificial and real vines for one type of sprayer. A fourth series of experiments on the artificial vineyard discriminated between three behaviour classes within 65 spraying modalities that combined sprayer types and sprayer settings (such as nozzle types). The discrimination was achieved using a PCA analysis that confirmed the soundness of the sampling strategy used. Overall, these results highlight the ability of the EvaSprayViti test facility to assess and rank the performance of vineyard sprayers.

Design, Numerical and Experimental Testing of a Flexible Test Bench for High-Speed Impact Shear-Cutting with Linear Motors

Given the use of high-strength steels to achieve lightweight construction goals, conventional shear-cutting processes are reaching their limits. Therefore, so-called high-speed impact cutting (HSIC) is used to achieve the required cut surface qualities. A new machine concept consisting of linear motors and an impact mass is presented to investigate HSIC. It allows all relevant parameters to be flexibly adjusted and measured. The design and construction of the test bench, as well as the mechanism for coupling the impact mass, are described. To validate the theoretically determined process speeds, the cutting process was recorded with high-speed cameras, and HSIC with a mild deep-drawing steel sheet was performed. It was discovered that very good cutting edges could be produced, which showed a significantly lower hardening depth than slowly cut reference samples. In addition, HSIC was numerically modelled in LS-DYNA, and the calculated cutting edges were compared with the real ones. With the help of adaptive meshing, a very good agreement for the cutting edges could be achieved. The results show the great potential of using a linear motor in HSIC.

New Random PWM Method at Constant Switching Frequency and Maximum Harmonic Reduction Created With a Flexible FPGA-Based Test Bench

It has been shown that the converters that integrate random PWM produce a spread spectrum in their harmonic emission, shortening the emission peaks. On the converter’s input side, the reduction minimizes electromagnetic interference EMI. On the output side of the converter, the reduction manages to smooth the voltage and current ripple in the load. We have built a flexible test bench (FTB) developed with FPGA to generate most of the proposed random PWM modes for converters. The conducted harmonic voltage emission of these modes, both on the input side of the converter and on the load side, has been measured and compared in a DC-DC Buck converter. FTB also has the ability to create new random PWM modes. Of the random modes, the ones that produce the greatest peak reductions are those with variable switching frequency. However, variable frequency modes lead to load feedback problems. A new random PWM method has been developed that significantly reduces the amplitude of the emission peaks but keeps the switching frequency constant.

Research on comfortable driving posture of car drivers based on muscle biomechanics

This paper aims to solve the problem of optimal design on a comfortable human-machine arrangement of car drivers with different physical signs under dynamic manipulation. Based on the biomechanical characteristic of human skeletal muscle and Hill muscle mechanics model, this paper constructs the human seat musculoskeletal model of 5th, 50th, and 95th percentile physical signs of Chinese car drivers under dynamic manipulation. The six-degree-of-freedom flexible test bench was set up and the center composite method was used to optimize the number of experiments. The consistency and relevance analysis of the actual measurement and dynamic manipulation simulation was carried out to comprehensively analyze the human-machine arrangement parameters such as vehicle seat, pedal, and steering wheel, so as to realize the optimization design of the hard point size of comfortable driving posture and verify the rationality and applicability of the test results through the vehicle road test.

Off-the-Shelf and Flexible Hybrid Frequency and Time Domain Experimental Architecture Setup for Electrochemical Energy Modules Testing Under Realistic Operating Conditions

This paper proposes a standard and flexible test bench architecture for the testing and modeling of electrochemical energy modules. It also presents a comprehensive methodology that enables to obtain accurate models under realistic operating conditions with a low computational cost. For this purpose, three different configuration modes of the experimental architecture setup are introduced. Finally, the test bench architecture and the experimental methodology proposed have been validated by the modeling and testing of a Li-ion battery pack and a supercapacitor module.

Back EMF Sensorless-Control Algorithm for High-Dynamic Performance PMSM

In this paper, a low-time-consuming and low-cost sensorless-control algorithm for high-dynamic performance permanent-magnet synchronous motors, both surface and internal permanent-magnet mounted for position and speed estimation, is introduced, discussed, and experimentally validated. This control algorithm is based on the estimation of rotor speed and angular position starting from the back electromotive force space-vector determination without voltage sensors by using the reference voltages given by the current controllers instead of the actual ones. This choice obviously introduces some errors that must be vanished by means of a compensating function. The novelties of the proposed estimation algorithm are the position-estimation equation and the process of compensation of the inverter phase lag that also suggests the final mathematical form of the estimation. The mathematical structure of the estimation guarantees a high degree of robustness against parameter variation as shown by the sensitivity analysis reported in this paper. Experimental verifications of the proposed sensorless-control system have been made with the aid of a flexible test bench for brushless motor electrical drives. The test results presented in this paper show the validity of the proposed low-cost sensorless-control algorithm and, above all, underline the high dynamic performances of the sensorless-control system also with a reduced equipment.

FPGA-based system-on-chip designs for real-time applications in particle physics

In this paper, we describe our experience in designing real-time hardware/software systems for data acquisition and analysis applications in particle physics, which are based on a system-on-chip (SoC) approach. Modern field-programmable gate array (FPGA) devices with embedded reduced instruction set computing (RISC) processor cores, high-speed low voltage differential signaling (LVDS) links and ready-to-use multigigabit transceivers allow development of compact systems with a substantial number of input-output (IO) channels, where required performance is obtained by a subtle separation of tasks among closely cooperating programmable hardware logic and user-friendly software environment. We report on the implementation of two such systems to illustrate the advantages of the SoC architectures. One is a flexible test bench for the off-shore read-out system of the ANTARES neutrino experiment. Another is a selective read-out processor device for the CMS electromagnetic calorimeter at LHC.