# Nonlinearities in Control Description and Design of an Electro Hydraulic Actuator for Flexible Nozzle Thrust Vector Control

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## Abstract

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## 1. Introduction

## 2. Actuator System—Description in the Model of a Rocket

## 3. Nonlinearity in Electro Hydraulic Actuator System

_{f}—the stiffness of a flexible joint is depicted in a much easier and simpler way than by Equation (1). An alternative to description of a flexible joint is basically mathematical description through LOOK UP function (in MatLab), based on experimental data, as shown in [1].

## 4. Non-Linear and Linear Description of Flow Characteristics of Distributor and Flexible Load

## 5. Conclusions

## Author Contributions

## Conflicts of Interest

## References

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**Figure 2.**Actuator in the rocket control structure. where: K—gain, Kα—feedback gain, ${W}_{\beta}^{\alpha}\left(s\right)$—transfer function of rocket, β—control position, Δ—dead band value.

**Figure 4.**Diagram that shows frequency and amplitude dependency and manifestation of system’s non-linear nature and saturation from velocity and acceleration.

**Figure 8.**Behavior of flexible joint with control offset (0.080 V, K = 1), control per position, elastic and inertial loads.

**Figure 10.**Behavior of flexible joint (model) without control offset, 2 Hz (±1 V), K = 1, input signal and friction in model of flexible joint.

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**MDPI and ACS Style**

Nauparac, D.; Prsic, D.; Milos, M. Nonlinearities in Control Description and Design of an Electro Hydraulic Actuator for Flexible Nozzle Thrust Vector Control. *Actuators* **2018**, *7*, 15.
https://doi.org/10.3390/act7020015

**AMA Style**

Nauparac D, Prsic D, Milos M. Nonlinearities in Control Description and Design of an Electro Hydraulic Actuator for Flexible Nozzle Thrust Vector Control. *Actuators*. 2018; 7(2):15.
https://doi.org/10.3390/act7020015

**Chicago/Turabian Style**

Nauparac, Dragan, Dragan Prsic, and Marko Milos. 2018. "Nonlinearities in Control Description and Design of an Electro Hydraulic Actuator for Flexible Nozzle Thrust Vector Control" *Actuators* 7, no. 2: 15.
https://doi.org/10.3390/act7020015