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One of the most important components constituting a homing guided missile is the seeker which basically consists of a detector with a servo-tracking loop. The performance of gimbal seeker is evaluated according to the line of sight (LOS) stability. The purpose of this paper is to present, investigate, and analyze the performance of two axes gimbal...
Contexts in source publication
Context 1
... In this paper, the disturbance torque due to static mass unbalance in elevation and azimuth gimbals can be obtained according to a reference frame XYZ on the assumption that the gimbal pivot is placed at the base CG point. For the elevation gimbal, the vertical plane XY is just considered because the gimbal CG offset, which lies on the rotation axis, does not create any torque on the pivot as shown in Figure 7(a). Therefore, Figure 7(b) indicates that the horizontal plane XZ is considered for the azimuth gimbal. ...
Context 2
... the elevation gimbal, the vertical plane XY is just considered because the gimbal CG offset, which lies on the rotation axis, does not create any torque on the pivot as shown in Figure 7(a). Therefore, Figure 7(b) indicates that the horizontal plane XZ is considered for the azimuth gimbal. ...
Citations
... A multi-axis gimbal is applied [10], and the integration of Time Delay on an adaptive controller for the system model is described [11]. It is imperative to prioritize the exploration and application of methods to manage the operational stability of the system, as outlined in reference [12][13][14][15], along with approaches for ensuring stability within the integrated controllers of the system. Several studies regarding the application of algorithms and control systems to make gimbals more stable have been carried out [16][17][18]. ...
... Research Article EAI Endorsed Transactions on AI and Robotics approach [3] for improving three axes gimbal seeker performance is an innovation. Hardware implementation of an ADRC controller [4] on multi-axis gimbal mechanism is promising work.Fractional order [5] of a gimbal platform that PID controller can be applied. ...
Gimbal or other stable platforms have structures that move according to its functions. This is for the purpose of keeping track of the goals to the fullest. Tracking targets can become difficult as the subject moves further and further away and they are out of the gimbal’s allowable viewing range. Besides, under the influence of noise signals form outside space, it becomes even more difficult to observe the gimbal’s targets. To overcome above disadvantages, this paper is presented an adjustment method to limit above risks. Adjusting Linear Quadratic Gaussian (LQG) for expensive gimbal systems, noise signals are processed purely by Kalman filters to improve the function of observing targets. In addition, proportional- integral-derivative (PID) controller, artificial neural network in this case is also considered to verify the effectiveness of control methods listed below. In particular, ANN is the most effective control method today to deal with unwanted signals. These unwanted signals can cause worsening conditions during the operation of systems.Therefore, artificial network (ANN) is a solution to information and communication security problems. Simulation is done by Matlab. Novelty of the work: no previous research has been published for this genre. The study of this genre with the use of artificial intelligence is suggestive of the study of artificial intellligence technologies at a higher level. This category is also a suggestion for studying a smoother control method based on existing data.
... A two-axis gimbal is a complex, multiple-input and multipleoutput (MIMO), nonlinear system that is susceptible to effects of unknown frictional torques, external/internal disturbances and modeling uncertainties. Various control strategies [4,5,6,7,8,9] have been developed to satisfy the accurate positioning requirements during stabilization and tracking related missions. Among these, a popular and a powerful technique is ADRC, which first estimates disturbances using ESO (extended state observer). ...
... The state observer (ESO), is constructed with the set of equations given in Eqn. 4. , and are the outputs of ESO. is the observed position, is the observed velocity and is the estimated disturbance. ...
The increasing demand for target tracking, environmental surveys, surveillance and mapping requires multi-axis gimbal systems with high tracking and stabilization performance. In this paper, first, computed torque model is generated to estimate the complex disturbances acting on the system. Then, two different control strategies based on active disturbance rejection control (ADRC) and computed torque model are implemented on a two-axis gimbal system. The purpose is to improve the robustness, environmental adaptability and tracking accuracy of the system and reduce the tuning effort of ADRC by integrating a neural network (NN) based disturbance compensator (NN assisted ADRC). In the second control strategy, NN is replaced with a computed torque model (CTM assisted ADRC), whose inputs come from plant outputs. The simulation results show that, NN and CTM assisted ADRC structures can decrease mean tracking errors up to 85.4% and 40.8%, respectively.
... Another proposal for the paper of Ding et al. [11] is the adaptive control using neural networks for the abovementioned model. rough Abdo et al.'s model [12], I propose the model using the PI control design method, and I will compare the advantages and disadvantages between PID controller and PI controller. rough Zhan et al.'s model [13], I can conduct a survey for this system with multiaxis gimbals (more than 2 axes). ...
Gimbal or an inertial stabilization platform (ISP) is used to stabilize the line of sight of an object or device that is tracking another object (LOS) with stationary or moving targets or targets moving forward. It can achieve precision when there is isolation between the tracker and the gimbal base. Studying the 2-axis tilt angle to create gimbal stability, especially in a camera, is a compelling subject for the automation field, as it is controlled by modern controllers. This paper presents a two-axis gimbal loop in which the LOS rate is stable, and I proceed to examine the stability of the system to get a better overview of the system properties. Through examining the stability of the system, I can choose from modern control methods to control them. The stability of the system used from the two analysis methods I present below gives me a visual view from the results achieved. The simulation is performed in MATLAB.
... Kennedy and Kennedy (2003) evaluated the performance of the two-DOF gimbal systems for angular situation of missile and airborne. The traditional and cascade controllers are applied through identifying their component for stabilisation of a two axes gimbal system (Abdo et al., 2014). Naderolasli and Tabatabaei (2019) proposed a Lyapunov-based adaptation mechanism for stabilisation of a two axes gimbal system through a feedback linearisation control structure. ...
... where 1 d T is the created disturbance due to the difference between two moments of inertia, 2 d T is composed of three terms resulting from inertia products and 3 d T is caused by the angular variation of that could be calculated through (Abdo et al., 2014): ...
... Neural network based sliding mode control approach has been implemented for disturbance rejection of a inertially stabilized platform (ISP) having actuator saturation in a gimbal system by Ding et al. (2019). In Abdo et al. (2015), two axes gimbal seeker system has been explored using cascade PID control design approach. In Zhan et al. (2014), optimal feedback stabilization control via linear matrix inequality (LMI) and convex optimization based technique is applied on a two axis gimbal system having saturation nonlinearity and various disturbances. ...
The gimbal or inertial stabilization platform (ISP) is used to stabilize the payload’s line of sight (LOS) towards a stationary or moving target. It can be achieved if there is isolation between the payload and the base of the gimbal. This paper presents a single-axis gimbal loop in which the LOS rate is stabilized using a robust proportional-integral-derivative (PID) controller. The PID controller parameters are obtained by using a graphical technique known as stability boundary locus (SBL) approach such that the overall gimbal stabilization loop will have some minimum specific gain margin and phase margin. The PID controller is further designed in the presence of time delay. The proposed controller is compared with PI control scheme available in literature for rise time, settling time, percentage overshoot, ISE, ITSE, IAE, and ITAE. The simulations are carried out in MATLAB which exhibit better results in comparison with PI control based approach.
... In all types of homing guidance, an onboard sensor, namely a seeker, is utilized to provide target data so as to ensure target acquisition and tracking by the missile. Indeed, the seeker is the eye of a homing missile and provides LOS (line-of-sight) angular rate and the measurements of target motion including relative range and closing velocity (see literature [9][10][11] for more details). ...
This paper describes a guidance method which is applicable in the leader–follower formation control. By considering limitations on communication among the aircraft, using airborne seekers for relative states measurement is proposed, and accordingly a kinematic model for the leader–follower system is developed. A main contribution of this work is analysis of the formation keeping in various flight scenarios when a cascade loop-based guidance strategy is used. In the proposed control structure, to regulate the relative ranges and the relative angles toward the desired values, two separate control channels are designed and to overcome the leader maneuvers, two proper acceleration estimators are employed. The effectiveness of the proposed guidance strategy is evaluated via simulation examples.
... Pole placement self-tuning control with the extended state observer has been proposed to improve the control performance and the disturbance elimination capability of a two-axis four-gimbal system [25]. In [26], a cascade control strategy for a two axes gimbal seeker system has been presented. In [27], an adaptive fractional order sliding mode controller has been employed for stabilization of the two-axis gimbal system. ...
... This means that the gimbals were assumed geometrically symmetric. The momentum products have been considered in the design procedure in small number of papers [22,26]. The gyro sensing errors and the cross coupling between two gimbals cause uncertainty in the products of inertia values. ...
... Although in some papers, the control torques are calculated to tend i q and i r to zero, but, in a general definition of stabilization scheme [28], these angular velocities should tend to non-zero reference velocities. This approach has been performed in recent works [22,26]. Considering 0 iref iref q r = = yields the conventional stabilization approach. ...
Background
This paper is devoted to adaptive feedback linearization based stabilization of a two-axis gimbal platform.
Methods
A Lyapunov based adaptation mechanism is proposed for stabilization of a two axes gimbal system through a feedback linearized control structure. The uncertainty of the products of inertia is incorporated in the design procedure.
Results
The performed computer simulations demonstrate the robust performance of the proposed two-axis gimbal stabilizer considering the cross-coupling effects between inner and outer gimbals.
Conclusion
The proposed control structure could be utilized in guided missiles, spacecraft, and navigation systems.
... To analyze the DTs of a seeker gimbal, its dynamic model should be established firstly. According to Newton's second law and the rotor dynamic theory, the basic motion equations for the azimuth and elevation axis could be directly obtained if the gimbals are considered as rigid bodies and mass unbalance is taken into account [19][20][21][22]. ...
... As can be seen from (15), (17), (19), and (20), there are many factors which would affect the bearing's FT, for example, geometric parameters, axial preload, lubricant viscous, and rotating speed. ...
In the manufacturing process of seekers, the reduction of disturbance torques (DTs) is a critical but time-consuming work. The innovation of the paper is to present a uniform method to measure and reduce mechanical DTs during gimbal’s assembly process. Firstly, the relationships between assembly parameters and DTs are established and analyzed by theoretical model. And then, a measuring system is established to measure the driven torque of the gimbal’s torque motor. With the goal of stabilizing and minimizing the driven torque, all assembly parameters relating to DTs could be adjusted. Through the proof of a lot of experiments, this proposed method could reduce the bias and fluctuation of these mechanical DTs. This method could also be used for the mechanical DTs reduction of most similar productions and improve the quality and efficiency during their system assembly process.
... Usual tracking sensors have limited beam or field of view; therefore, these sensors are installed on two-degree-of-freedom gimbals which are capable of moving in azimuth and elevation directions. For more information about two-degree-of-freedom gimbals and their modeling see [3,4]. The function of two degrees of freedom gimbal is positioning of the desired angular position such that the angular errors reported by the sensor are vanished [5]. ...
... It should be noted that tracking systems typically are designed, so that has no steady state error when the target velocity is constant. For this reason, it is also known as a zero velocity-error system [3]. Fig. 11(a) shows a unit parabolic input response of system without time-delay and unit parabolic response of system with time-delay in the new structure and tracking error of these two from their reference are shown in Fig. 11(b). ...
In this paper, a new tracking control structure is proposed to decrease the time-delay effect of tracking sensor. To achieve this purpose, an angular position sensor, which generally exists in tracking systems, is used together with the tracking sensor. Also, a compensator is designed and applied to a system with time-delay in order to obtain a behavior same as a system without time-delay. Relying only on tracking sensor may lead to reduce the tracking speed and to increase tracking error. However, it is shown that by using the proposed reformative structure, the speed of tracking and the tracking error can be compensated significantly. In the next step, the performance of the new structure in two cases of constant time-delay and variable time-delay are evaluated and their stability conditions are analyzed. Finally, robustness of the proposed structure is analyzed.
http://www.sciencedirect.com/science/article/pii/S0019057816300398
