Optimal Error-Clamping Design for Position-Based Visual Servoing of a 2-DOF Model Helicopter

2011 ◽  
Author(s):  
M. Alizadeh ◽  
C. Ratanasawanya ◽  
M. Mehrandezh ◽  
R. Paranjape
Keyword(s):  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Vision System ◽  
Physical Space ◽  
Linear Quadratic Regulator ◽  
Image Plane ◽  
Reference Trajectory ◽  
Linear Quadratic ◽  
Feed Forward ◽  
Model Helicopter

A vision-based servoing technique is proposed for a 2 degrees-of-freedom (dof) model helicopter equipped with a monocular vision system. In general, these techniques can be categorized as image- and position-based, where the task error is defined in the image plane in the former and in the physical space in the latter. The 2-dof model helicopter requires a configuration-dependent feed-forward control to compensate for gravitational forces when servoing on a ground target. Therefore, a position-based visual servoing deems more appropriate for precision control. Image information collected from a ground object, with known geometry a priori, is used to calculate the desired pose of the camera and correspondingly the desired joint angles of the model helicopter. To assure a smooth servoing, the task error is parameterized, using the information obtained from the linearaized image Jacobian, and time scaled to form a moving reference trajectory. At the higher level, a Linear Quadratic Regulator (LQR), augmented with a feed-forward term and an integrator, is used to track this trajectory. The discretization of the reference trajectory is achieved by an error-clamping strategy for optimal performance. The proposed technique was tested on a 2-dof model helicopter capable of pitch and yaw maneuvers carrying a light-weight off-the-shelf video camera. The test results show that the optimized controller can servo the model helicopter to a hovering pose for an image acquisition rate of as low as 2 frames per second.

Stabilizing and Swinging-Up the Inverted Pendulum Using PI and PID Controllers Based on Reduced Linear Quadratic Regulator Tuned by PSO

2015 ◽  
Vol 4 (4) ◽  
pp. 52-69 ◽  
Author(s):  
M. E. Mousa ◽  
M. A. Ebrahim ◽  
M. A. Moustafa Hassan
Keyword(s):  
Pid Controller ◽  
Inverted Pendulum ◽  
Research Work ◽  
Linear Quadratic Regulator ◽  
Nonlinear Problems ◽  
Pid Controllers ◽  
Linear Quadratic ◽  
Swarm Optimization ◽  
Feed Forward ◽  
Forward Gain

The inherited instabilities in the Inverted Pendulum (IP) system make it one of the most difficult nonlinear problems in the control theory. In this research work, Proportional –Integral and Derivative (PID) Controller with a feed forward gain is used with Reduced Linear Quadratic Regulator (RLQR) for stabilizing the Cart Position and Swinging-up the Pendulum angle. Tuning the Controllers' gains is achieved by using Particle Swarm Optimization (PSO) Technique. Obtaining the combined PID controllers' gains with a feed forward gain and RLQR is a multi-dimensions control problem. The Proposed Controllers give minimum Settling Time, Rise Time, Undershoot and Over shoot for both the Cart Position and the Pendulum angle. A disturbance with different amplitudes is applied to the system, and the results showed the robustness of the systems based on the tuned controllers. The overall results are promising.

Lateral Stability Analysis for Car-Trailer Combinations

2016 ◽  
Author(s):  
Eungkil Lee ◽  
Tao Sun ◽  
Yuping He
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Parametric Study ◽  
Degrees Of Freedom ◽  
Linear Quadratic Regulator ◽  
Lateral Stability ◽  
Linear Quadratic ◽  
Lqr Control ◽  
Ct System

This paper presents a parametric study of linear lateral stability of a car-trailer (CT) combination in order to examine the fidelity, complexity, and applicability for control algorithm development for CT systems. Using MATLAB software, a linear yaw-roll model with 5 degrees of freedom (DOF) is developed to represent the CT combination. In the case of linear stability analysis, a parametric study was carried out using eigenvalue analysis based on a linear yaw-roll CT model with varying parameters. Built upon the linear stability analysis, an active trailer differential braking (ATDB) controller was designed for the CT system using the linear quadratic regulator (LQR) technique. The simulation study presented in this paper shows the effectiveness of the proposed LQR control design and the influence of different trailer parameters.

An automatic system for a helicopter autopilot performance evaluation

2019 ◽  
Vol 91 (6) ◽  
pp. 880-885 ◽  
Author(s):  
Antoni Kopyt ◽  
Sebastian Topczewski ◽  
Marcin Zugaj ◽  
Przemyslaw Bibik
Keyword(s):  
Performance Evaluation ◽  
Flight Control ◽  
Automatic System ◽  
Control Algorithm ◽  
Linear Quadratic Regulator ◽  
Algorithm Analysis ◽  
Evaluation Methodology ◽  
Reference Trajectory ◽  
Linear Quadratic ◽  
Content Type

Purpose The purpose of this paper is to elaborate and develop an automatic system for automatic flight control system (AFCS) performance evaluation. Consequently, the developed AFCS algorithm is implemented and tested in a virtual environment on one of the mission task elements (MTEs) described in Aeronautical Design Standard 33 (ADS-33) performance specification. Design/methodology/approach Control algorithm is based on the Linear Quadratic Regulator (LQR) which is adopted to work as a controller in this case. Developed controller allows for automatic flight of the helicopter via desired three-dimensional trajectory by calculating iteratively deviations between desired and actual helicopter position and multiplying it by gains obtained from the LQR methodology. For the AFCS algorithm validation, the objective data analysis is done based on specified task accomplishment requirements, reference trajectory and actual flight parameters. Findings In the paper, a description of an automatic flight control algorithm for small helicopter and its evaluation methodology is presented. Necessary information about helicopter dynamic model is included. The test and algorithm analysis are performed on a slalom maneuver, on which the handling qualities are calculated. Practical implications Developed automatic flight control algorithm can be adapted and used in autopilot for a small helicopter. Methodology of evaluation of an AFCS performance can be used in different applications and cases. Originality/value In the paper, an automatic flight control algorithm for small helicopter and solution for the validation of developed AFCS algorithms are presented.

scholarly journals Uncalibrated Visual Servoing for Underwater Vehicle Manipulator Systems with an Eye in Hand Configuration Camera

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5469 ◽  
Author(s):  
Jiyong Li ◽  
Hai Huang ◽  
Yang Xu ◽  
Han Wu ◽  
Lei Wan
Keyword(s):  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Image Plane ◽  
Adaptive Controller ◽  
Underwater Vehicle ◽  
Lyapunov Theory ◽  
Time Varying ◽  
Position Information ◽  
Smooth Tracking ◽  
Uncalibrated Visual Servoing

This paper presents an uncalibrated visual servoing scheme for underwater vehicle manipulator systems (UVMSs) with an eye-in-hand camera under uncertainties. These uncertainties contain vision sensor parameters, UVMS kinematics and feature position information. At first, a linear separation approach is addressed to collect these uncertainties into vectors, and this approach can also be utilized in other free-floating based manipulator systems. Secondly, a novel nonlinear adaptive controller is proposed to achieve image error convergence by estimating these vectors, the gradient projection method is utilized to optimize the restoring moments. Thirdly, a high order disturbance observer is addressed to deal with time-varying disturbances, and the convergence of the image errors is proved under the Lyapunov theory. Finally, in order to illustrate the effectiveness of the proposed method, numerical simulations based on a 9 degrees of freedom (DOFs) UVMS with an eye-in-hand camera are conducted. In simulations, the UVMS is expected to track a circle trajectory on the image plane, meanwhile, time-varying disturbances are exerted on the system. The proposed scheme can achieve accurate and smooth tracking results during simulations.

Backstepping Controller Design for a 5 DOF Spherical Inverted Pendulum

2019 ◽  
Vol 41 ◽  
pp. 37-50 ◽  
Author(s):  
Soukaina Krafes ◽  
Zakaria Chalh ◽  
Abdelmjid Saka
Keyword(s):  
Degrees Of Freedom ◽  
Inverted Pendulum ◽  
Controller Design ◽  
Linear Quadratic Regulator ◽  
Performance Comparison ◽  
Virtual Reality Environment ◽  
Linear Quadratic ◽  
Control Scheme ◽  
Linearized System ◽  
Backstepping Controller

This paper presents a Backstepping controller for five degrees of freedom Spherical Inverted Pendulum. Since the system is nonlinear, unstable, underactuated and MIMO and has a nonsquare form, the classic control design cannot be applied to control it. In order to remedy this problem, we propose in this paper a new method based on hierarchical steps of the Backstepping controller taking into a count the nonlinearities that cannot be neglected. Furthermore, a Linear Quadratic Regulator controller and LQR + PID based on the linearized system model are also designed for performance comparison. Finally, a simulation study is carried out to prove the effectiveness of proposed control scheme and is validated using the virtual reality environment that proves the performance of the Backstepping controller over the linear ones where it brings the pendulum from any initial condition in the upper hemisphere while the base is brought to the origin of the coordinates.

Design and Simulation of Three Degrees-of-Freedom Tracking Systems for Capsule Endoscope

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Ibrahim K. Mohammed
Keyword(s):  
Degrees Of Freedom ◽  
Magnetic Levitation ◽  
Tracking System ◽  
New Technology ◽  
Linear Quadratic Regulator ◽  
Capsule Endoscope ◽  
Linear Quadratic ◽  
Stability Parameters ◽  
Actuation System ◽  
Three Degrees Of Freedom

Wireless capsule endoscopes (WCE) are a new technology for inspection of the intestines, which offer many advantages over conventional endoscopes, while devices currently in use are passive and can only follow the natural transit of the intestines. There is a considerable interest in methods of controlled actuation for these devices. In this paper, an actuation system based on magnetic levitation is proposed, utilizing a small permanent magnet within the capsule and an arrangement of digitally controlled electromagnet placed on a movable frame. The objective of this paper is to design a multi-input multi-output (MIMO), three degrees-of-freedom (3DOF) tracking system for capsule endoscope. Two techniques, entire eigenstructure assignment (EEA) and linear quadratic regulator (LQR), are presented to design the controller of the system. The performance of the EEA and LQR controllers was compared based on the stability parameters to validate the proposed actuation system. Finally, simulation results suggest that the LQR approach can be used to synthesize a suitable and simple controller for this application.

Controlling an Underactuated Two-Wheeled Mobile Robot: A Constraint-Following Approach

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Hui Yin ◽  
Ye-Hwa Chen ◽  
Dejie Yu
Keyword(s):  
Mobile Robot ◽  
Degrees Of Freedom ◽  
Control Design ◽  
Nonholonomic Constraints ◽  
Linear Quadratic Regulator ◽  
Wheeled Mobile Robot ◽  
Linear Quadratic ◽  
Control Goal ◽  
Standard Linear ◽  
Following Error

Controlling underactuated systems is a challenging problem in control engineering. This paper presents a novel constraint-following approach for control design of an underactuated two-wheeled mobile robot (2 WMR), which has two degrees-of-freedom (DOF) to be controlled but only one actuator. The control goal is to drive the 2 WMR to follow a set of constraints, which may be holonomic or nonholonomic constraints. The constraint is considered in a more general form than the previous studies on constraint-following control (hence including a wider range of constraints). No auxiliary variables or pseudo variables are required for the control design. The proposed control only uses physical variables. We show that the proposed control is able to deal with both holonomic and nonholonomic constraints by forcing the constraint-following error to converge to zero, even if the system is not initially on the constraint manifold. Using this control design, we investigate two cases regarding different constraints on the 2 WMR motion, one for a holonomic constraint and the other for a nonholonomic constraint. Simulation results show that the proposed control is able to drive the 2 WMR to follow the constraints in both cases. Furthermore, the standard linear quadratic regulator (LQR) control is applied as a comparison in the simulations, which reflects the advantage of the proposed control.

A new criterion for comfort assessment of in-wheel motor electric vehicles

2020 ◽  
pp. 107754632097718
Author(s):  
Hossein Salmani ◽  
Milad Abbasi ◽  
Tondar Fahimi Zand ◽  
Mohammad Fard ◽  
Reza Nakhaie Jazar
Keyword(s):  
Electric Vehicle ◽  
Degrees Of Freedom ◽  
Optimization Technique ◽  
Optimization Procedure ◽  
Linear Quadratic Regulator ◽  
International Organization ◽  
Design Parameters ◽  
Linear Quadratic ◽  
International Organization For Standardization ◽  
Design Variables

A novel optimization technique was implemented to investigate the effects of vibrations on comfort of occupants to maintain oscillations in an acceptable zone in accordance with the International Organization for Standardization 2631 standard. In this regard, a newly introduced comfort indicator was defined as discomfort criterion (DiC). The effectiveness of the proposed measure was investigated throughout the suspension optimization of an in-wheel motor electric vehicle which almost doubled the unsprung mass by adding an electric motor to the wheel assembly. First, a spatial oscillatory model of the electric vehicle with eight degrees of freedom was developed, and the linear quadratic regulator control scheme is selected to control an actuator in an active suspension. Road excitations were then generated by applying the power spectral density of road class B–C provided by the International Organization for Standardization 8608 standard. The exceedance from the reduced comfort limit (in accordance with the International Organization for Standardization 2631 standard) and wheel travel (WT) of the vehicle were considered as design objectives. Finally, using a novel optimization procedure, the optimum condition and impact factor of the design variables, as well as counterplots of the design objectives with respect to the effective design parameters, were extracted and analyzed. Results proved the proposed indicator, that is, discomfort criterion (DiC) as a reliable measure to assess suspension systems’ performance effectively.

An improved vision calibration method for coaxial alignment microassembly

2014 ◽  
Vol 34 (3) ◽  
pp. 237-243 ◽  
Author(s):  
Xin Ye ◽  
Jun Gao ◽  
Zhijing Zhang ◽  
Chao Shao ◽  
Guangyuan Shao
Keyword(s):  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Vision System ◽  
Image Plane ◽  
Calibration Method ◽  
Corner Detection ◽  
Objective Lens ◽  
Content Type ◽  
Assembly Accuracy ◽  
Methodological Guidelines

Purpose – The purpose of this paper is to propose a sub-pixel calibration method for a microassembly system with coaxial alignment function (MSCA) because traditional sub-pixel calibration approaches cannot be used in this system. Design/methodology/approach – The in-house microassembly system comprises a six degrees of freedom (6-DOF) large motion serial robot with microgrippers, a hexapod 6-DOF precision alignment worktable and a vision system whose optical axis of the microscope is parallel with the horizontal plane. A prism with special coating is fixed in front of the objective lens; thus, two parts’ Figures, namely the images of target and base part, can be acquired simultaneously. The relative discrepancy between the two parts can be calculated from image plane coordinate instead of calculating space transformation matrix. Therefore, the traditional calibration method cannot be applied in this microassembly system. An improved calibration method including the check corner detection solves the distortion coefficient conversely. This new way can detect the corner at sub-pixel accuracy. The experiment proves that the assembly accuracy of the coaxial microassembly system which has been calibrated by the new method can reach micrometer level. Findings – The calibration results indicate that solving the distortion conversely could improve the assembly accuracy of MSCA. Originality/value – The paper provides certain calibration methodological guidelines for devices with 2 dimensions or 2.5 dimensions, such as microelectromechanical systems devices, using MSCA.

Motion planning of spacecraft with obstacle avoidance under low uncertainty using the improved equal-collision-probability-curve and improved linear quadratic regulator strategy

2019 ◽  
Vol 233 (14) ◽  
pp. 5456-5467
Author(s):  
Wang Yi ◽  
Chen Xiaoqian ◽  
Bai Yuzhu ◽  
Cao Lu ◽  
Zhu Xiaozhou
Keyword(s):  
Motion Planning ◽  
Obstacle Avoidance ◽  
Linear Quadratic Regulator ◽  
Collision Probability ◽  
Planning Problem ◽  
Reference Trajectory ◽  
Linear Quadratic ◽  
Probability Curve ◽  
Proximity Operations ◽  
Low Uncertainty

In terms of the motion planning problem of spacecraft proximity operations with obstacle avoidance under low uncertainty, the improved equal-collision-probability-curve and improved linear quadratic regulator (IECPC-ILQR) strategy is proposed. Firstly, the novel function of the IECPC algorithm is developed to generate the avoidance control impulse. Subsequently, the ILQR is designed to track the reference trajectory. Furthermore, combining the improved ECPC algorithm with the ILQR controller, the composite controller of the IECPC-ILQR strategy is obtained and is implemented on the chaser spacecraft. Compared with the traditional ECPC algorithm, the IECPC-ILQR strategy can avoid collision in the presence of low uncertainty. Furthermore, the proposed avoidance strategy can obtain higher control precision while requiring the same fuel. Finally, numerical simulations verify the effectiveness of the proposed IECPC-ILQR strategy.

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