50 lines
2.9 KiB
Markdown
50 lines
2.9 KiB
Markdown
|
+++
|
|||
|
|
title = "Force feedback versus acceleration feedback in active vibration isolation"
|
|||
|
|
author = ["Thomas Dehaeze"]
|
|||
|
|
draft = false
|
|||
|
|
+++
|
|||
|
|
|
|||
|
|
Tags
|
|||
|
|
: [Vibration Isolation]({{< relref "vibration_isolation" >}})
|
|||
|
|
|
|||
|
|
Reference
|
|||
|
|
: <sup id="525e1e237b885f81fae3c25a3036ba6f"><a href="#preumont02_force_feedb_versus_accel_feedb" title="Preumont, Fran\ccois, Bossens, \& Abu-Hanieh, Force Feedback Versus Acceleration Feedback in Active Vibration Isolation, {Journal of Sound and Vibration}, v(4), 605-613 (2002).">(Preumont {\it et al.}, 2002)</a></sup>
|
|||
|
|
|
|||
|
|
Author(s)
|
|||
|
|
: Preumont, A., A. Francois, Bossens, F., & Abu-Hanieh, A.
|
|||
|
|
|
|||
|
|
Year
|
|||
|
|
: 2002
|
|||
|
|
|
|||
|
|
Summary:
|
|||
|
|
|
|||
|
|
- Compares the force feedback and acceleration feedback for active damping
|
|||
|
|
- The use of a force sensor always give alternating poles and zeros in the open-loop transfer function between for force actuator and the force sensor which **guarantees the stability of the closed loop**
|
|||
|
|
- Acceleration feedback produces alternating poles and zeros only when the flexible structure is stiff compared to the isolation system
|
|||
|
|
|
|||
|
|
The force applied to a **rigid body** is proportional to its acceleration, thus sensing the total interface force gives a measured of the absolute acceleration of the solid body.
|
|||
|
|
Thus force feedback and acceleration feedback are equivalent for solid bodies.
|
|||
|
|
When there is a flexible payload, the two sensing options are not longer equivalent.
|
|||
|
|
|
|||
|
|
- For light payload (Figure [1](#org7b4f6ee)), the acceleration feedback gives larger damping on the higher mode.
|
|||
|
|
- For heavy payload (Figure [2](#org361b58f)), the acceleration feedback do not give alternating poles and zeros and thus for high control gains, the system becomes unstable
|
|||
|
|
|
|||
|
|
<a id="org7b4f6ee"></a>
|
|||
|
|
|
|||
|
|
{{< figure src="/ox-hugo/preumont02_force_acc_fb_light.png" caption="Figure 1: Root locus for **light** flexible payload, (a) Force feedback, (b) acceleration feedback" >}}
|
|||
|
|
|
|||
|
|
<a id="org361b58f"></a>
|
|||
|
|
|
|||
|
|
{{< figure src="/ox-hugo/preumont02_force_acc_fb_heavy.png" caption="Figure 2: Root locus for **heavy** flexible payload, (a) Force feedback, (b) acceleration feedback" >}}
|
|||
|
|
|
|||
|
|
Guaranteed stability of the force feedback:
|
|||
|
|
|
|||
|
|
> If two arbitrary flexible, undamped structures are connected with a single-axis soft isolator with force feedback, the poles and zeros of the open-loop transfer function from the force actuator to the force sensor alternate on the imaginary axis.
|
|||
|
|
|
|||
|
|
The same is true for the transfer function from the force actuator to the relative displacement of the actuator.
|
|||
|
|
|
|||
|
|
> According to physical interpretation of the zeros, they represent the resonances of the subsystem constrained by the sensor and the actuator.
|
|||
|
|
|
|||
|
|
# Bibliography
|
|||
|
|
<a id="preumont02_force_feedb_versus_accel_feedb"></a>Preumont, A., A. Fran\ccois, Bossens, F., & Abu-Hanieh, A., *Force feedback versus acceleration feedback in active vibration isolation*, Journal of Sound and Vibration, *257(4)*, 605–613 (2002). http://dx.doi.org/10.1006/jsvi.2002.5047 [↩](#525e1e237b885f81fae3c25a3036ba6f)
|