Some approaches on instantaneous angular speed measurement using a two-phase n poles AC generator as sensor

Horodincă, Mihăiţă; Ciurdea, Ionut; Chitariu, Dragos-Florin; Munteanu, Adriana; Boca, Mihai

doi:10.1016/j.measurement.2020.107636

Cited by 10 publications

(27 citation statements)

References 42 publications

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“…For six different values of amplitudes (A 1 increases and A 2 decreases), the evolution of the combination frequency f c and its average value was determined on the vibration beating simulated signal, as Figure 9 indicates, using a high accuracy measurement technique from a previous work [42]. Here each peak describes the value of frequency f c in vibration beating node.…”

Section: The Evolution Of Frequency For Resultant Vibration In Beatinmentioning

confidence: 99%

“…In order to measure the average value of the instantaneous angular speed (IAS) ω 1 of the main spindle (shaft 1) rigorously, the technique described in our previous work [42] was used (with a two phase multi-pole AC generator placed in the jaw chuck, as an IAS sensor). The same technique (which refers only to signal processing, briefly described later on) was used for an accurate measurement of the combination frequency f c .…”

Section: Methodsmentioning

confidence: 99%

“…As a consequence, the angular speed ω 2 = 2πf 2 has two possible values (ω 2 = 109.1716 rad/s or ω 2 = 109.3016 rad/s), as does the speed ratio (ω 2 /ω 1 ) of the driving belt (with ω 1 = 109.2369 rad/s). To find the right value of f 2 (and ω 2 as well) the technique described in [42] should be used (with an IAS sensor placed on shaft 2).…”

Section: The Description Of the Beating Phenomenon In Vibration Displmentioning

confidence: 99%

“…The dominant component of the signal from Figure 7 is the displacement of resultant vibration y1 + y2. The frequency measurement method [42] is based Figure 10. The evolution of the instantaneous combination frequency on simulated vibration beating during a beat period (the same condition as in Figure 9, except for the amplitudes relationship:…”

Section: Appl Sci 2020 10 X For Peer Review 11 Of 21mentioning

confidence: 99%

“…The dominant component of the signal from Figure 7 is the displacement of resultant vibration y 1 + y 2 . The frequency measurement method [42] is based on detection of zero-crossing moments of this signal (a topic discussed later on). It is obvious that many other additional vibrations of the lathe headstock (some of them with high frequency) disturb the accuracy of the zero-crossing detections, as a main reason for the noisy evolution from Figure 11.…”

Section: Appl Sci 2020 10 X For Peer Review 11 Of 21mentioning

confidence: 99%

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An Experimental Approach on Beating in Vibration Due to Rotational Unbalance

et al. 2020

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This paper proposes a study in theoretical and experimental terms focused on the vibration beating phenomenon produced in particular circumstances: the addition of vibrations generated by two rotating unbalanced shafts placed inside a lathe headstock, with a flat friction belt transmission between the shafts. The study was done on a simple computer-assisted experimental setup for absolute vibration velocity signal acquisition, signal processing and simulation. The input signal is generated by a horizontal geophone as the sensor, placed on a headstock. By numerical integration (using an original antiderivative calculus and signal correction method) a vibration velocity signal was converted into a vibration displacement signal. In this way, an absolute velocity vibration sensor was transformed into an absolute displacement vibration sensor. An important accomplishment in the evolution of the resultant vibration frequency (or combination frequency as well) of the beating vibration displacement signal was revealed by numerical simulation, which was fully confirmed by experiments. In opposition to some previously reported research results, it was discovered that the combination frequency is slightly variable (tens of millihertz variation over the full frequency range) and it has a periodic pattern. This pattern has negative or positive peaks (depending on the relationship of amplitudes and frequencies of vibrations involved in the beating) placed systematically in the nodes of the beating phenomena. Some other achievements on issues involved in the beating phenomenon description were also accomplished. A study on a simulated signal proves the high theoretical accuracy of the method used for combination frequency measurement, with less than 3 microhertz full frequency range error. Furthermore, a study on the experimental determination of the dynamic amplification factor of the combination vibration (5.824) due to the resonant behaviour of the headstock and lathe on its foundation was performed, based on computer-aided analysis (curve fitting) of the free damped response. These achievements ensure a better approach on vibration beating phenomenon and dynamic balancing conditions and requirements.

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Section: The Evolution Of Frequency For Resultant Vibration In Beatinmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: The Description Of the Beating Phenomenon In Vibration Displmentioning

confidence: 99%

Section: Appl Sci 2020 10 X For Peer Review 11 Of 21mentioning

confidence: 99%

Section: Appl Sci 2020 10 X For Peer Review 11 Of 21mentioning

confidence: 99%

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An Experimental Approach on Beating in Vibration Due to Rotational Unbalance

et al. 2020

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Fixed‐time velocity‐free coordination control for human‐robot systems without any approximation function

Zeng

Yang

2023

Intl J Robust & Nonlinear

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In this paper, the fixed‐time coordination control problem is addressed for a class of uncertain human‐robot systems without velocity information. Specifically, due to the absence of approximation function, the developed control scheme is more practical. Firstly, a new fixed‐time velocity observer is introduced to estimate unmeasured velocities with the homogeneity theory. Then, the performance of the velocity observer in the presence of parametric uncertainties and non‐parametric uncertainties is analyzed seriously. Furthermore, a novel distributed continuous fixed‐time control (DCFTC) scheme is proposed. Compared with the existing velocity‐free controllers, fixed‐time convergence is achieved both for velocity estimation and trajectory tracking. More than that, distributed control is realized by using graph theoretic notions. Finally, numerical simulation results and experiment results demonstrate the efficacy and superior performance of the proposed velocity estimation method and control algorithms.

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