Navigation Functionalities for an Autonomous UAV Helicopter

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44 CHAPTER 4. PATH FOLLOWING CONTROL MODE braking condition is activated when the following condition becomes true: with vbrake = vbrake < vcruise (4.18) � |(2 · lend · Acc + v2 end )| (4.19) where lend is the distance, calculated along the path segment, that the helicopter has to fly to reach the end of the segment and Acc is the desired acceleration during the braking phase (its value is set to 1.2 m/s). vend is the desired velocity at the end of each path segment and it is assigned by the path planner. The condition 4.18 means that the helicopter must start to brake when the distance to the end of the segment is equal to the distance necessary to bring the helicopter from the velocity vcruise to vend with the desired acceleration. If vend is greater than vcruise the helicopter increases the velocity instead. The method used for the calculation of lend is explained in Paper I. The calculation of vtarg2 takes into account the kinematic constraints described by the equations in 4.14. For safety reasons the flight envelope has been limited to: rmax = 40 rad/sec maximum yaw rate, φmax = 15 deg maximum roll angle, θmax = 15 deg maximum pitch angle and for the vertical acceleration a load factor of Nzmax = Tmax/g = 1.1. The value of Nzmax has been chosen using the fact that Nzmax = 1.1 means increasing the helicopter weight 10 percent. The maximum takeoff weight of the RMAX is 94kg and the RMAX weight used in this experimental test is around 80kg, so a load factor of 1.1 ensures enough safety. The second equation in 4.14 represents the forward velocity u2 achievable with the maximum pitch angle. It is not considered as a constraint here since the cruise velocity assigned
4.2. TRAJECTORY GENERATOR 45 by the path planner will always be smaller than u2. umax is calculated using 4.15. Finally we can calculate vtarg2 as: vtarg2 = umax τ b x (4.20) where τ b x is the projection of the vector in 4.16 on the helicopter Xb body axis. Fig. 4.6 shows the three velocities u1, u3 and u4, depending on the path curvature radius, calculated from equations in 4.14 using the limitation rmax, φmax and Nzmax. The most limiting velocity is u3, which means the maximum roll angle φmax is the most limiting factor for the maximum velocity umax. The situation can change if the takeoff weight is more than 80kg, in this case Nzmax could become the limiting factor. Figure 4.6: Velocity constraint due to the maximum yaw rate, roll angle and load factor. It is important to mention that the velocity umax is calculated using equation 4.14 which is derived from a trimmed flight condition. As
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Linköping Studies in Science and T
Page 5: Acknowledgements This work would ha
Page 9 and 10: Contents 1 Introduction 1 2 Overvie
Page 11 and 12: Chapter 1 Introduction An Unmanned
Page 13 and 14: of the environment in order to avoi
Page 15 and 16: Chapter 2 Overview This chapter pre
Page 17 and 18: 2.1. UAV SOFTWARE ARCHITECTURE 7 wh
Page 19 and 20: 2.2. THE UAV HELICOPTER PLATFORM 9
Page 21 and 22: 2.2. THE UAV HELICOPTER PLATFORM 11
Page 23 and 24: Chapter 3 Simulation 3.1 Introducti
Page 25 and 26: 3.2. HARDWARE-IN-THE-LOOP SIMULATIO
Page 27 and 28: 3.3. REFERENCE FRAMES 17 3.3 Refere
Page 29 and 30: 3.4. THE AUGMENTED RMAX DYNAMIC MOD
Page 31 and 32: 3.4. THE AUGMENTED RMAX DYNAMIC MOD
Page 33 and 34: 3.5. SIMULATION RESULTS 23 3.5 Simu
Page 35 and 36: 3.5. SIMULATION RESULTS 25 Figure 3
Page 37 and 38: 3.5. SIMULATION RESULTS 27 Figure 3
Page 39 and 40: Chapter 4 Path Following Control Mo
Page 41 and 42: 4.2. TRAJECTORY GENERATOR 31 Figure
Page 43 and 44: 4.2. TRAJECTORY GENERATOR 33 Fig. 4
Page 45 and 46: 4.2. TRAJECTORY GENERATOR 35 be use
Page 47 and 48: 4.2. TRAJECTORY GENERATOR 37 4.2.3
Page 49 and 50: 4.2. TRAJECTORY GENERATOR 39 radius
Page 51 and 52: 4.2. TRAJECTORY GENERATOR 41 Calcul
Page 53: 4.2. TRAJECTORY GENERATOR 43 Figure
Page 57 and 58: 4.2. TRAJECTORY GENERATOR 47 Figure
Page 59 and 60: 4.3. OUTER LOOP CONTROL EQUATIONS 4
Page 61 and 62: 4.4. EXPERIMENTAL RESULTS 51 Up [m]
Page 63 and 64: 4.5. CONCLUSIONS 53 1 + s 1 C(s) =
Page 65 and 66: 4.5. CONCLUSIONS 55 Vel [m/s] 20 18
Page 67 and 68: Chapter 5 Sensor fusion for vision
Page 69 and 70: composed of three accelerometers an
Page 71 and 72: 5.1. FILTER ARCHITECTURE 61 filter
Page 73 and 74: 5.1. FILTER ARCHITECTURE 63 north,
Page 75 and 76: 5.2. EXPERIMENTAL RESULTS 65 Figure
Page 77 and 78: 5.2. EXPERIMENTAL RESULTS 67 Figure
Page 79 and 80: 5.2. EXPERIMENTAL RESULTS 69 by the
Page 81 and 82: 5.3. CONCLUSION 71 vision system st
Page 83 and 84: BIBLIOGRAPHY 73 [9] E. Frazzoli. Ro
Page 85 and 86: Appendix A 75
Page 87 and 88: A.1. PAPER I 77 is a three-dimensio
Page 89 and 90: A.1. PAPER I 79 The reference point
Page 91 and 92: A.1. PAPER I 81 Path Av Err Max Err
Page 93 and 94: A.2. PAPER II 83 From Motion Planni
Page 105 and 106:
A.2. PAPER II 95 From Motion Planni
Page 107 and 108:
A.3. PAPER III 97 A.3 Paper III Aut
Page 109 and 110:
A.3. PAPER III 99 the projection of
Page 111 and 112:
A.3. PAPER III 101 yes Tbo > Tlim2
Page 113 and 114:
A.3. PAPER III 103 immediately afte
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A.3. PAPER III 105 altitude [m] 20
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A.3. PAPER III 107 Fig. 10. Flight
Page 121 and 122:
Department of Computer and Informat
Page 123 and 124:
No 598 Rego Granlund: C 3 Fire - A
Page 125 and 126:
No 1024 Aleksandra Tešanovic: Towa
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Navigation Functionalities for an Autonomous UAV Helicopter

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