A Fast Online Estimator of the Main Vibration Mode of Mechanisms from a Biased Slightly Damped Signal

Benftima, Selma; Feliu-Batlle, Vicente; Benattia, Selma; Salhi, Salah

doi:10.1109/iecon49645.2022.9969085

Cited by 1 publication

(2 citation statements)

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“…Their main advantages are recapitulated in the following: (1) they enable the measurement of vibrational signals as well as deflections, (2) they are easily implemented and used and can be reusable and (3) they are relatively low cost. However, strain gauges have several drawbacks [11,36], such as: (1) huge temperature variations, (2) high-frequency noise capable of saturating the actuators and (3) offset, which leads to a steady-state error that affects the end position of the link [38]. These drawbacks will be addressed in the next section.…”

Section: The Outer Loopmentioning

confidence: 99%

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Fractional Modeling and Control of Lightweight 1 DOF Flexible Robots Robust to Sensor Disturbances and Payload Changes

2023

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Model design and motion control are considered the cornerstones of the robotic field that allow for achieving performance tasks. This article proposes a new dynamic modeling and control approach for very lightweight mechanical systems carrying payloads. The selection of the model and the design of the control are elaborated on using a fractional order framework under different conditions. The use of fractional order calculus is justified by the better performance that reveals a fractional order model compared to an integer order model of similar complexity. The mechanical structure of very lightweight manipulators has vibrations that impede the accurate positioning of their end effector. Moreover, they have actuators with high friction and sensors to measure the vibrations, which often are strain gauges, that have offset and high-frequency noise. All these mentioned problems might degrade the mechanical system’s performance. Hence, to overcome these inconveniences, two nested-loop controls are examined: an inner loop that controls the motor dynamics and removes the friction effects and an outer loop implemented to eliminate the beam vibrations by adapting the input-state feedback linearization technique. Then, we propose a new fractional order control scheme that (1) removes the strain gauge offset disturbances, (2) reduces the risk of the actuator’s saturation caused by the high-frequency noise of strain gauges and (3) reduces the dynamic effects of huge payload changes. We prove that our fractional controller has enhanced robustness with respect to the above-mentioned problems. Finally, the investigated approach is validated experimentally by applying it to a lightweight robot mounted on an air table.

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Section: The Outer Loopmentioning

confidence: 99%

“…Assume a value + at which h( + ) > 0. Expression (38) shows that ω c varies continuously with . Then, h( ) is a continuous function and, consequently, if h( − ) < 0 and h( + ) > 0, a value 0 exists such that h( 0 ) = 0 and h( ) < 0 in the interval ∈ [ − , 0 ).…”

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confidence: 99%