| Both sides previous revisionPrevious revisionNext revision | Previous revision |
| ece6554:project_quadcopter [2023/03/21 11:33] – [Implementation] classes | ece6554:project_quadcopter [2024/08/20 21:38] (current) – external edit 127.0.0.1 |
|---|
| ==== Implementation ==== | ==== Implementation ==== |
| |
| Functional code stubs for the implementation are provided in the {{ ECE6554:projects:quadcopter.zip | quadcopter zipfile}}. They implement a constant control signal that most definitely fails to do the job, but provide enough structure to complete the project. Comments in the code should help to realize the necessary improvements. <color red>[NOTE: This zipfile is not yet ready. Working on it now.]</color> | Functional code stubs for the implementation are provided in the {{ ECE6554:projects:quadcopter.zip | quadcopter zipfile}}. They implement a constant control signal that most definitely fails to do the job, but provide enough structure to complete the project. Comments in the code should help to realize the necessary improvements. |
| |
| ===== Control Approaches ===== | ===== Control Approaches ===== |
| | ----------- |
| There are several approaches to stabilizing the quadcopter. Which one to take depends on your comfort with control theory. They are listed below. | There are several approaches to stabilizing the quadcopter. Which one to take depends on your comfort with control theory. They are listed below. |
| |
| **Inner/Outer Control Loops:** Since it is known that control of (horizontaol) position requires angling the quadcopter (there are no means to directly control these state coordinates), a common technique for control of the quadcopter is to design a fast inner loop that achieves fast angular control with the position variables ignored. This approach works because the position state variables don't factor into the angular rate equations. The next step would be to then assume great or perfect tracking of angular signals and look at the position substates with angular inputs. The inner and outer loops can be adaptively controlled using different techniques. For example, the angular portion could be controlled using a more geometric method; a simple version of something like this was in the homework with satellite angular rate control. The linear portion could be controlled using standard linear techniques. | **Inner/Outer Control Loops:** Since it is known that control of (horizontaol) position requires angling the quadcopter (there are no means to directly control these state coordinates), a common technique for control of the quadcopter is to design a fast inner loop that achieves fast angular control with the position variables ignored. This approach works because the position state variables don't factor into the angular rate equations. The next step would be to then assume great or perfect tracking of angular signals and look at the position substates with angular inputs. The inner and outer loops can be adaptively controlled using different techniques. For example, the angular portion could be controlled using a more geometric method; a simple version of something like this was in the homework with satellite angular rate control. The linear portion could be controlled using standard linear techniques. |
| |
| **Geometric Control:** There are geometric approaches that impose a transformation of state to render the system more linear looking. A combination of geometric transformations of the signals plus linear control permit stabilization and trajectory tracking of non-aggressive maneuvers. There are flavors of this that afford aggressive maneuvering along feasible, specified trajectories. That part is a bit more involved and is not sought here. | **Geometric Control:** There are geometric approaches that impose a transformation of state to render the system more linear looking. A combination of geometric transformations of the signals plus linear control permit stabilization and trajectory tracking of non-aggressive maneuvers. There are flavors of this that afford aggressive maneuvering along feasible, specified trajectories. Aggressive controllers are a bit more involved and not sought here. |
| |
| |
| ===== Activities ===== | ===== Activities ===== |
| | ----------- |
| Though the activities below involve application of linear control, the full nonlinear equations should be used for simulation. As a sanity check, it is usually a good idea to first implement with the linear system simulated as a confirmation. Once it works, switch to the nonlinear system dynamics and linear control law. Performance should be similar but degrade slightly. For expected documentation for the deliverables, see the [[ECE6554:Project_PlanarHeli | Planar Bi-Rotor Helicopter]] project description. | Though the activities below involve application of linear control, the full nonlinear equations should be used for simulation. As a sanity check, it is usually a good idea to first implement with the linear system simulated as a confirmation. Once it works, switch to the nonlinear system dynamics and linear control law. Performance should be similar but degrade slightly. For expected documentation for the deliverables, see the [[ECE6554:Project_PlanarHeli | Planar Bi-Rotor Helicopter]] project description. |
| |
| |
| ===== References ===== | ===== References ===== |
| | --------------------- |
| |
| For sure you need to be careful with these references. In addition to different reference frame conventions between Aerospace engineers and others, plus different ways of representing the $SE(3)$ Lie group state, there are actually slightly different dynamical equations for the quadcopter. The references below just give some idea for how static controllers are synthesized for these systems. The model chosen depends on what the authors wish to demonstrate or what kinds of constraints their control method has. | For sure you need to be careful with these references. In addition to different reference frame conventions between Aerospace engineers and others, plus different ways of representing the $SE(3)$ Lie group state, there are actually slightly different dynamical equations for the quadcopter. The references below just give some idea for how static controllers are synthesized for these systems. The model chosen depends on what the authors wish to demonstrate or what kinds of constraints their control method has. |
