I’m going to be rich!!!
In the fall of 2010, while completing my bachelor’s senior project, I accidentally designed a helicopter that flies without its rotors moving! I’m going to make billions!
Posts Tagged ‘ helicopter ’
In the fall of 2010, while completing my bachelor’s senior project, I accidentally designed a helicopter that flies without its rotors moving! I’m going to make billions!
My first quadrotor frame design is simple, sturdy, reliable, and a bit ugly. I have made no attempt to make it cute, flashy, or visually desirable in any way. If and when I determine that the structural design performs well, I’ll use some better tools to make a more flashy design. Until then, I’ll be flying on my raw cut aluminum frame.
My basic design is two 24 inch(610 mm) X 1/2 inch(13 mm) X 1/2 inch(13 mm) square aluminum arms. I knotched both in the center so that they can cross each other. There are two 5 1/4 inch(133 mm) alumimum plates holding everything strong and square. The frame is very strong, rigid, and relatively low weight.
Here is the initial parts list for my quadcopter design:
Product | Description | Quantity | Price |
---|---|---|---|
Turnigy Brushless Outrunner 2217 20turn 860kv 22A |
4 | $53.12 ($13.28ea) |
|
Turnigy ESC Plush 30amp |
4 | $48.76 ($12.19ea) |
|
Turnigy LiPo 5000mAh 3S 25C Lipo |
1 | $27.43 | |
XT60 Connectors Male/Female (5 pairs) |
1 | $3.19 | |
Turnigy Balancer/Charger Accucel-6 50W 6A w/ accessories |
1 | $22.99 | |
Pyramid Power Supply PS12KX 10-amp 13.8-volt |
1 | $46.99 | |
APCProp 12 x 3.8″ Slow Flyer |
2 | $7.90 ($3.95ea) |
|
APCProp 12 x 3.8″ Slow Flyer Pusher |
2 | $11.84 ($5.92ea) |
|
Spektrum DX5e 5 Channel 2.4 GHz DSM2 Transmitter |
1 | $59.99 | |
Spektrum AR500 5 Channel 2.4 GHz DSM2 Receiver |
1 | $39.99 | |
LPCXpresso LPC1768 ARM Cortex-M3 Development Board |
1 | $28.50 | |
9 DOF Sensor Stick 3-Axis Gyro, Accelerometer, Magnetometer |
1 | $99.99 | |
OR Gate CMOS Quad 2-Input |
1 | $1.00 | |
Buffer CMOS Quad 2-Input |
1 | $1.00 | |
Aluminum Tubing 6061 1/2″ x 1/2″ x 72″, 0.063″ Wall |
1 | $21.14 | |
Aluminum Sheet 6061 12″ x 12″, 0.063″ Thick |
1 | $10.06 | |
Coleman Wire 16 Gauge 100 Feet |
1 | $11.24 | |
Bullet Connectors 3.5mm 3 Pairs |
4 | $19.80 ($4.95ea) |
The aim of this design is for an extremely aggressive quadcopter. My design goals are for the stabilization system to handle VERY abrupt changes in attitude and able to recover from any acrobatic mishap. I’ll be adding a mode for acrobatics where absolute angles are not used for stabilization. Instead, the stabilzer will hold to a rotational rate. If an acrobatic maneuver goes south, one switch flip will be able to bring the helicopter back to a stabile hover. The only remaining control not adjusted by the stabilizer is the throttle.
I’m sure that there will be additional items I will need but haven’t thought of. I will try to keep this list up to date for those of you using it for your own copter build.
EDIT: added 16-gauge wire and 3.5mm connectors
I have been researching a variety of multi-rotor helicopter setups for some time. I’ve been trying to identify the strengths and weaknesses of each design type. I have come up with an initial design for my quad-rotor helicopter. In attempts to create a very aggressive aircraft, I have designed the propellers to be a close as possible, as large as possible, and the motors to have a high power to weight ratio. All of my assumptions about quadcopter design are very spectulative since I haven’t ever built one before.
My first matter of design is a powerful CPU. My fly-by-wire T-Rex 600 project used 4 Arduinos and they left a sour taste in my mouth. Arduinos are great for quick prototyping but anything with substance needs a better processor. Besides, I’m a Computer Engineer so I can’t justify using someone else’s poorly designed microcontroller libraries. My microcontroller of choice for this project is the LPC1768 ARM Cortex-M3 by NXP Semiconductors. It is a powerhouse! I’ve written most of the low-level hardware drivers and a few of the higher level routines, such as PID controllers and Collective Cyclic Throttle Mixing (CCTM). The combination of the ARM’s Cortex-M3 core with NXP’s hardware peripherials makes this as amazingly powerful design. ARM+NXP=Happiness!
For aircraft attitude measurement, I’m planning on using the 9DOF Sensor Stick from Sparkfun. Version 2 is still under design so I’ll have to wait on that. I’m going to implement 3 different types of sensor fusion algorithms and see which type works the best. The 3 algorithms are:
In the animation above, the two circles representing the propellers show the two sizes I will test. The inner circles are a 12×3.8″ APCprop and the outer circles are a 14×4.7″ APCprop. I haven’t seen another helicopter use the 14″ props before so I’ll get the 12″ props working first.
This is an explanation of the animation per level:
Level One (bottom):
Level Two (between the two metal plates):
Level Three (top):
Outer Arms:
I know that having the props close together makes the attitude harder to stabilize. On the other hand, having the props close together will (I hope) induce much more torque on the frame from the motors. This will help me overcome the lame yaw response of most quadrotor helicopters. I’m banking on the fact that my CPU will be running at 100 MHz and I’ll hopefully have the sensor fusion filters and PID controller running at 400+Hz. This should allow me to precisely adjust each axis of stabilization. For better discrete calculus computations (integration and differentation) I’ll try running the sensor fusion algorithms above 1kHz and only commanding the ESCs at their maximum speed (50Hz-400Hz). This will make the computations more accurate because each time step will produce less error.
Past:
I recently graduated from the University of Utah in Computer Engineering. My senior project was a fly-by-wire system for an unmanned helicopter. We used an Align T-Rex 600 ESP helicopter for the project. Designing a stabilization system for this size of helicopter presents many problems. Given that the tips of the blades travel at 350 mph, physical danger was obviously the biggest concern. We successfully implemented our design.
Even though we felt moderate success, we didn’t feel that our system performed as well as it could have. All the supporting hardware and software was implemented but the time needed to calibrate the many features of stabilization caused us to end the project before all features could be utilized. The excessive calibration time is a result of calibrating a 53 inch helicopter during flight. Any changes in the system had to be modified very slowly.
This project gave me a lot of experience with inertial measurement and feedback control. It also gave me a HUGE desire to make something better!
Future:
Now I begin a multi-rotor helicopter project. I aim to fix all the faults in the previous design while overcoming many of the short comings of current multi-rotor designs. I will start by designing a 4 rotor system because it is the cheapest. Once I master the quadcopter, I’ll try a hexacopter or an octocopter. I have been impressed by many multicopter designs. Some are:
My goals are to:
My initial design will be very minimal. I will start off with only a basic quad-rotor design controlled by a transmitter/receiver pair. No other communication will be used. I’m designing this to be minimal so that I can focus on the inertial measurements and feedback control. Once these are mastered, I’ll add fluffy features like: