学位论文 > 优秀研究生学位论文题录展示

Optimization of the Mechanical Design of the Dual Axis Inertially Stabilized Platform for the Line of Sight Stabilization

作　者: Hany Fathalla Hassan Mokbel
导　师: 曹国华
学　校: 长春理工大学
专　业: 机械电子工程
关键词: Line of Sight (LOS) Inertially Stabilized Platform (ISP) Gimbals Fast SteeringMirror (FSM) Laser Detection and Ranging (LADAR) System design and integration Mathematical Modeling Finite Element Method (FEM) Modal Analysis CompliantMechanisms Piezoelectric Actuators
分类号: TH122
类　型: 博士论文
年　份: 2013年
下　载: 1次
引　用: 0次
阅　读: 论文下载

内容摘要

For the purpose of stabilizing the Line Of Sight (LOS) of Electro-Optical (Eo) surveillance and tracking system, a Dual Axis Inertially Stabilized Platform (ISP) is required to isolate the LOS from the carrier disturbances. Due to the maneuver of both the target and the observer, The LOS is misdirected instantaneously, which requires the presence of an ISP to null theses rotational disturbances and maintains the LOS of the EO devices stable and directed to the target. The orthogonal dual axis ISP is the minimum required set of ISPs to achieve the efficient stabilization. Generally, for the purpose of directing the LOS, two methods are commonly used; the Mass Stabilization and the Mirror Stabilization.Based on The Mass Stabilization method, this research was aiming to design a high performance, small size and light weight3D Scanner consists mainly of a Laser Range Finder (LRF), a Complementary Metal-Oxide-Semiconductor (CMOS) camera, Pilot green laser, two electronic Compasses and rate gyro to obtain the range, Azimuth and Elevation angles for each point in the Field of View (FOV). The ISP structure consists of the inner gimbal that carrying the EO devices and rotates in the Elevation direction about the Y-axis, and the outer gimbal that makes the cross elevation rotation (Azimuth) about the Z axis. The designed ISP carrying these EO devices has achieved Azimuth range of±120°, Elevation range of-10°：+190°, with angular rates and accelerations of200°/s and100°/s2respectively in both directions, Bandwidth of100Hz, and resolution of0.9μradian. The Electro-Mechanical system’s design process implements many disciplines and requires the integration of different design facilities to assure the optimal system’s design. The design was dynamically optimized based on the Finite Element Method (FEM) Modal Analysis. The weight of the payload carrying frame was decreased by35%and the1st torsional mode of vibration was increased by22%of the original design. Moreover, the overall dynamic performance of the inner gimbal was optimized and the dynamic performance improved by75%. The results declare that the FEM Modal Analysis is an effective tool to optimize the system’s dynamic performance to assure the optimal working conditions are sitting far from the resonating failure. The Kinematics and dynamics models were discussed in details to facilitate understanding the precession of the ISP, as well as. to simulate the designed system to assure the ability of the system to act diligently according to the maximum designed requirements. This work not only gives the mathematical model for the two-axis ISP, but the more important is that it gives the methodology to derive and analyze it, to direct the design toward optimality. Additionally, the designed controller has achieved high robustness, zero steady state error, fast response, minimum overshoot and minimum settling time. The importance of taking advantage of the strengths of each individual design facility has been declared trough the integrating the3D solid Modeling, Mathematical Modeling, FEM Analysis, and Computer Simulation in a continuous feedback process to achieve the optimal design of the ISP. As an application of the designed ISP, a Laser Detection and Ranging (LADAR) system has been designed and implemented to facilitate mobile targets path tracking and terrestrial scanning of large objects. The design simplicity, low cost of the system and the ability of building such systems by researchers in laboratory were the key features for this work. The LADAR system was loaded on two-axis orthogonal rotary table, and consists of LRF, control unit, remote control unit, optical imaging system (camera and optical telescope), two electronic compass, green pilot laser, power unit, communication unit, portable computer, power supply, cables and connectors. The interface for the system is acquired using the LabVIEW software, where each point is depicted by a distance, Azimuth rotation angle and Elevation rotation angle in a spherical coordinate system with respect to the origin of the LRF sensing lens. The system architecture and the mathematical modeling for the data manipulating were discussed in details along with the results of the field experiments.On the other hand, based on the Mirror stabilization method, the design results of a Fast Steering Mirror (FSM) have reached a Bandwidth of1kHz, resolution of0.04μradian, angular acceleration of16×103rad/s2, an optical rotational angle of±2mille radian, maximum angular velocity of8radians/s, with a clear elliptical optical aperture of2×3inch. The FSM system architecture, mirror structure, compliant mechanisms’ design, and actuators’ selection were discussed in details. Nevertheless, a general discussion for the FSM system enhancement was introduced for further optimization processes.Moreover, this research has established a new concept for the LOS stabilization that combines the advantages of both classical systems and avoids their weakness points, that we call "Ball Stabilization". It permits the angular rotations of the EO devices in the Azimuth and Elevation direction inside a spherical enclosure without the need of gimbals for each direction. The system was designed to simulate the human’s eye shape and rotation behavior inside its cavity, where the tension of the muscles makes nearly pure rotation about the two axes orthogonal to the LOS-axis with their origin fixed in the eye’s center. This new system implements piezoelectric edge actuators which are strictly connected to the payload and together perform the combined angular rotations inside the spherical enclosure. The elimination of gimbals reduces the size and inertia forces of the system, which facilitates the achievement of high resolution, angular rates and accelerations. For proofing this concept, an ISP system was designed and simulated to have a FOV of±30°in both directions, band width of1552Hz, resolution of1×10-50angular rate of210°/s, angular acceleration of24×103°/s2, within a compact size of130mm in diameter, and total weight of1.19kg.Finally, this work has presented a real Ball Stabilization Opto-Electro-Mechanical ISP system design, manufacturing and integration process that has an outer diameter of220mm and can achieve the required stabilization about the Elevation and Azimuth directions by rotating the payload on the inner surface of the ball. This real system has achieved another two degrees of freedom by applying four driven rolling rings on the outer surface of the ball to rotate the ball itself, which achieved additional stabilization about the Elevation and Roll axes.

全文目录

ABSTRACT  6-10
Contents  10-16
List of Figures  16-22
List of Tables  22-24
Chapter 1:Introduction  24-48
  1.1 Statement of the Problem  25-26
  1.2 Objective of the Present Work  26
  1.3 Scope of the Present Work  26-27
  1.4 Dual Axis Inertially Stabilized Platform Configurations,Design Considerations, and Applications  27-46
    1.4.1 Classification of the LOS Stabilization Approaches  27-28
      1.4.1.1 Direct and Indirect Line Of Sight Stabilization  28
      1.4.1.2 Mass and Mirror Line Of Sight Stabilization  28
    1.4.2 Applications of Inertially Stabilized Platforms  28-33
      1.4.2.1 Autonomous Driving of Intelligent Vehicles  29
      1.4.2.2 Electro一Optical(EO)Tracking System  29-30
      1.4.2.3 Imaging  30-31
      1.4.2.4 Communication Antennas  31
      1.4.2.5 Inertial Navigation System(INS)  31-33
    1.4.3 ISP Components and Design Tradeoffs  33-39
      1.4.3.1 Gyros  33-37
      1.4.3.2 Bearings and Suspension  37-38
      1.4.3.3 Motors and Actuators  38
      1.4.3.4 Relative-Motion Transducers  38-39
      1.4.3.5 Rotating Electrical Interfaces  39
    1.4.4 The Double-Gimbal ISP  39-41
      1.4.4.1 Gimbals Kinematics  39-40
      1.4.4.2 Gimbals Dynamics  40-41
    1.4.5 Structural Dynamic Analysis of ISP  41-43
      1.4.5.1 Modes of Response  41-42
      1.4.5.2 Modal Analysis and Structural Dynamics  42
      1.4.5.3 Modal Analysis Using FEM  42-43
    1.4.6 Summery of Errors in ISP  43-44
    1.4.7 The Control System  44-46
    1.4.8 Design Methodology of an ISP  46
  1.5 Summery  46-48
Chapter 2:Inertially Stabilized Platform Optimal Design  48-94
  2.1 The System Requirements  48-49
  2.2 Basic System Configuration  49-51
  2.3 3D Solid Modeling  51-53
  2.4 Mathematical Modeling  53-74
    2.4.1 Inertially Stabilized Platform Kinematics Model  58-60
    2.4.2 Inertially Stabilized Platform Dynamic Model  60-74
      2.4.2.1 Derivations of the Dynamic Model  60-63
      2.4.2.2 Dynamic Analysis for the Inner Gimbal  63-68
      2.4.2.3 Dynamic Analysis for the Outer Gimbal  68-74
  2.5 FEM Modal Analysis  74-84
    2.5.1 The ISP's FEM Modal Analysis  75-83
      2.5.1.1 The Original ISP's FEM Modal Analysis  76-78
      2.5.1.2 The Payload Carrying Frame FEM Modal Analysis  78-80
      2.5.1.3 The Payload Frame with the EO Devices Modal Analysis  80-82
      2.5.1.4 The Whole Inner Gimbal FEM Modal Analysis  82-83
    2.5.2 Summary of the FEM Modal Analysis  83-84
  2.6 Servo Control System  84-92
    2.6.1 Robust PI Controller for Line of Sight Stabilization  85-88
    2.6.2 Non-linear Fuzzy Logic PI Controller for Line of Sight Stabilization  88-92
  2.7 Summary  92-94
Chapter 3:Design,Implementation and Experimental Testing of 3D LADAR System for Mobile Targets Path Tracking and Terrestrial Scanning  94-116
  3.1 Introduction  94-97
  3.2 LADAR System Structure  97-101
    3.2.1 Laser Range Finder  97-98
    3.2.2 Rotary Table  98
    3.2.3 Optical Imaging System(Camera and Optical Telescope)  98-99
    3.2.4 Electronic Compass  99
    3.2.5 Green Pilot Laser  99-100
    3.2.6 Power Unit  100
    3.2.7 Communication Unit  100-101
    3.2.8 Interface Computer  101
    3.2.9 Power Supply Source  101
  3.3 LADAR System Mathematical Modeling  101-107
    3.3.1 The 1~(st) Mathematical Model  102-105
    3.3.2 The 2~(nd) Mathematical Model  105-107
  3.4 Experimental Testing  107-113
    3.4.1 Mobile Target Path Tracking  108-111
    3.4.2 Terrestrial Scanning of Large Objects  111-113
  3.5 Summary  113-116
Chapter 4:The Mechanical Design of Two-Axis Fast Steering Mirror for Optical Beam Guidance  116-132
  4.1 Introduction  116-117
  4.2 FSM System Architecture and Application Theory  117-125
    4.2.1 Mechanical Design and Control System Considerations  121
    4.2.2 Mirror Design  121-122
    4.2.3 Piezoelectric Actuators  122-123
    4.2.4 Compliant Mechanisms  123-125
      4.2.4.1 Axial Flexure Design  123-125
      4.2.4.2 Extension Spring  125
  4.3 System Analysis  125-129
  4.4 Discussion and Optimization  129-130
  4.5 Summary  130-132
Chapter 5:A New Concept for the Line of Sight Stabilization  132-176
  5.1 Introduction  132-134
  5.2 Working Principle  134-136
  5.3 System Analysis  136-143
    5.3.1 Forces Acting on the Rollers During Rest  138-139
    5.3.2 Moments Acting on the Rotating Structure during Motion  139-141
    5.3.3 Conditions for Optimal LOS Stabilization Process  141-143
  5.4 System's Mathematical Modeling  143-147
    5.4.1 Kinematics Modeling  144-146
    5.4.2 Dynamics Modeling  146-147
  5.5 Design and Simulation of Two-Axes ISP Based on the Ball Stabilization Method  147-165
    5.5.1 System Architecture  147-150
    5.5.2 System Analysis  150-153
    5.5.3 System Performance Simulation  153-164
    5.5.4 FEM Modal Analysis  164-165
  5.6 Experimental Work  165-172
    5.6.1 The Actual System Configuration  166-168
    5.6.2 Dimensional and Accuracy Testing  168-169
    5.6.3 The Driving Actuators and Wheels  169-170
    5.6.4 Augmented Stabilization  170-172
  5.7 Summary and Comparison between the Different Stabilization Methods  172-176
Chapter 6:Conclusions,Contributions and Future Work  176-182
  6.1 Conclusions  176-179
  6.2 Contributions  179
  6.3 Recommendations for Future Work  179-182
Acknowledgement  182-184
References  184-192
Appendix A  192-196
Appendix B  196-198
List of Publications  198

Optimization of the Mechanical Design of the Dual Axis Inertially Stabilized Platform for the Line of Sight Stabilization

内容摘要

全文目录

相似论文