HOBBYEAGLE A3 Mini 6-Axis Gyro Stabilizer System User Manual

HOBBYEAGLE A3 Mini 6-Axis Gyro Stabilizer System

INSTALLATION

NOTES

• Never use the hot-melt glue or nylon ties to fix the gyro onto the airplane!
• You need only one piece of the double-sided tapes each time, amounting type that is too soft or too thick can affect the performance of the gyro.
• The gyro is a sensing device, please make enough space around it and keep as far away from other electronic devices or wires as possible.

Mounting Orientation
Use one of the supplied double-sided tapes to attach the gyro to the airplane firmly. For best performance, the gyro should be mounted as close to the C.G. as possible, and the housing edges must be aligned exactly parallel to all three rotation axes of the airplane. The gyro can be attached flat or upright, and even upside down, however, you must ensure the arrow on the sticker always point to the heading direction, otherwise the gyro will not work normally in ANGLE, LEVEL and HOVER modes.

CONNECTION

Receiver Connection
A3 Mini supports PPM and multi-protocol digital serial receivers which allows you to connect the receiver to the gyro with one single wire on the slot [Serial RX]. When operating in single-line mode, the gyro uses the preset channel assignment to recognize the channels from the receiver. Please check if the current channel mapping matches the channel order of your transmitter via the configurator or programming card. After each time you have changed the receiver type, you can choose either to reset the channels, or to keep existing settings. Choose “None” for those channels you do not use.

Serial Protocol Supported| AIL| ELE| RUD| AIL2| MODE| GAIN| THR
---|---|---|---|---|---|---|---
PPM Receiver| CH1| CH2| CH4| CH6| CH5| None| CH3
Futaba S.Bus / WFLY WBus| CH1| CH2| CH4| CH6| CH5| None| CH3
FrSky / RadioLink / JETI SBus| CH1| CH2| CH4| CH6| CH5| None| CH3
Spektrum DSM2/X 1024 Satellite| CH2| CH3| CH4| CH6| CH5| None| CH1
Spektrum DSM2/X 2048 Satellite| CH2| CH3| CH4| CH6| CH5| None| CH1
Spektrum SRXL| CH2| CH3| CH4| CH6| CH5| None| CH1
Multiplex SRXL/JR XBUS Mode B| CH2| CH3| CH4| CH6| CH5| None| CH1
Graupner SUMD| CH2| CH3| CH4| CH6| CH5| None| CH1
FlySky iBUS| CH1| CH2| CH4| CH6| CH5| None| CH3
JETI EXBus (F/W V1.2 required)| CH2| CH4| CH5| CH3| CH6| None| CH1

NOTES

• Please note that the GAIN channel is disabled by default. To enable the remote master gain, you need to specify a channel number for it via the configurator or the programming card.
• Pay attention to the polarity of the plugs. The orange or white signal line must always be on the inner side of the gyro.
• A special optional adapter or converter is required if you want to use a Spektrum satellite (remote) receiver or a SRXL2 remote receiver.

Wing Type and Servo Connection
A3 Mini supports Standard Fixed-wing, Flying-wing (Delta-wing) and V-Tail. Always turn off the mixing function of delta-wing or v-tail in the transmitter because the gyro will provide such mixing features by itself. Check the Servo Monitor of the transmitter and verify that each stick controls only one channel.

Single / Dual Aileron Control

• The gyro works in single aileron control mode when there is only one aileron input connected. Both output channels of AIL and AIL2 issue the same signal for the aileron servos, just like what a Y-extended lead works.
• The gyro works in dual aileron control mode if both aileron inputs are connected, in this mode, output channels of AIL and AIL2 are operated separately.

FLIGHT MODES

A3 Mini provides 6 flight modes which can be switched by using a 3-position switch of the transmitter during flight. The expected flight mode associated to each position of the switch can be specified via the configurator or the programming card. The default setting is OFF – NORMAL – LEVEL. The color of the LED shows the current flight mode of the gyro while in use.

GYRO OFF Mode
When operating in GYRO OFF mode the gyro will be deactivated completely, and the airplane will be completely under the control of your transmitter as it was before installing the gyro. This mode is usually used for testing purpose only.

NORMAL Mode
The NORMAL mode, also known as the ‘Rate mode’, is the most basic function of the gyro. It works based on the rotation rate control of each axis of the airplane. When operating in this mode, the gyro will only correct currently occurring rotational movements, a momentary reaction will be applied to the servos when the airplane rotating on corresponding axis, the servos will move back to their neutral position as soon as the airplane stops rotating. The NORMAL mode can be used with nearly any size and type of airplanes. It can effectively improve the stability and precision of the airplane and reduce the stall point specially.

LOCK Mode
The LOCK mode is also known as the ‘Attitude Lock mode’, ‘3D mode’ or ‘AVCS mode’. Different from NORMAL mode, the gyro will perform a permanent correction for rotational movements on each axis constantly. That is when you release the sticks the airplane will stop and lock its current position immediately. This mode is well suited for practicing basic 3D maneuvers such as hovering or knife edge. Since it can help you to lock the attitude of the airplane, it is also helpful for landing.

ANGLE Mode (Former Trainer Mode)
The ANGLE mode, also known as the ‘Trainer mode’ or ‘Attitude mode’, will limit the maximum angle of the airplane on both roll and pitch axes. Roll and loop are not allowed in this mode, the airplane will be stabilized all the time, independent of any stick input. This prevents the airplane from being tilted into a larger angle that may cause a danger. As soon as the sticks are released, the airplane will be brought back to horizontal position automatically. You can use this mode as emergency rescue, or in other applications, e.g., to have a training for new beginners or to use for FPV. The maximum allowed angle of this mode can be specified via the configurator or programming card.
LEVEL Mode
The LEVEL mode is also known as the ‘Auto-Level mode’, ‘Auto-Balance mode’ or ‘Horizon mode’. When operating in this mode, the airplane will be brought to horizontal position automatically when releasing the sticks. Different from the ANGLE mode, there is no maximum angle limitation in this mode and the airplane will be stabilized only when there is no specific control input from aileron and elevator sticks. This mode can be used if the pilot becomes disoriented and would like to save the airplane from crashing.

HOVER Mode
The HOVER mode, also known as the ‘Auto-Hover mode’, provides the same functionality as the LEVEL mode. The only difference is that when you release the sticks, the airplane will be brought to vertical position (nose up) and keeps hovering. This mode is designed to help you to learn hovering maneuver and reduce the probability of crashing.

GAIN ADJUSTMENT

Basic Gain
A3 Mini provides separate adjustment of basic gain on aileron, elevator and rudder. Basic gain determines the reaction strength of the gyro. In general, the higher the gain the harder the airplane will stop after rotation and the more stable and precise the airplane will fly. But if the gain is too high the airplane will tend to oscillate at high frequency on the corresponding axis. If too small, the operation and stability will not be so good, and the airplane does not stop precisely and overshoots. The gyro will be deactivated completely if you set the basic gain to 0%. For the first flight test it is recommended to start with a lower basic gain setting (e.g., 30%) and switch the gyro to NORMAL mode. In case the airplane starts to oscillate then reduce the gain of the corresponding axis. If the control feels weak and imprecise and does not hold position when stopping then increase the gain, according to this approach, fine tune the basic gain until you get the best performance.

Mode Gain
Furthermore, the gyro gain of each axis can also be adjusted separately for each flight mode, including Lock Gain, Angle Gain, Level Gain and Hover Gain, these gains are normally used after the basic gain has been properly set and will only work with the corresponding flight mode.

Remote Master Gain
The remote master gain is used to change the basic gain of aileron, elevator and rudder at the same time in flight. By using a slide lever on the transmitter, the rate of the gain can be decreased linearly from 100% to 0%, you can also use a 3-position switch to get a 3 rates selection of the gain. Remote master gain will always default to 100% if you do not connect this channel.

GYRO DIRECTION

After installation, lift the airplane up and make it quickly rotate around the roll, pitch and yaw axes respectively. Make sure all the control surfaces react in the correct directions referring to the figures below.

VERY IMPORTANT: It is extremely important to make sure that the gyro reacts in the correct direction for each channel  before flight. An opposite reaction of the gyro could lead to losing control or even crash!

Check the gyro direction for Aileron
Quickly rotate the airplane left or right around the roll axis, the ailerons should react in the expected directions as shown below.

Check the gyro direction for Elevator
Quickly rotate the airplane up or down around the pitch axis, the elevator should react in the expected direction as shown below.

Check the gyro direction for Rudder
Quickly rotate the airplane left or right around the yaw axis, the rudder should react in the expected direction as shown below.

Quick Gyro Reversing
A3 Mini also provides you a quick approach to reverse the gyro direction without connecting it to a PC or a programming card. For example, to reverse the gyro direction of Aileron, press and hold the button while moving and holding the Aileron stick right or left for about 2 seconds, release both the button and the stick when the LED flashes White once, indicating that the gyro direction of Aileron has been reversed and saved. Similarly, move the Elevator stick up or down for Elevator channel and move the Rudder stick right or left for Rudder channel while long pressing the button until the LED starts to flash White once.

LEVEL AND HOVER CALIBRATION

When flying in ANGLE mode or LEVEL mode, gyro needs to know the angle of the airplane in both roll and pitch directions, this is achieved by calculating the attitude of its own. A small angle deviation caused by installation can lead to an unexpected behavior when flying in ANGLE mode or LEVEL mode. For this reason, a level calibration is recommended to offset the error caused by installation and to establish a proper level reference of the airplane after installing the gyro.

1. Before calibrating, the airplane should be placed on the horizontal ground and make the wing parallel to the ground. Make the airplane slightly nose-up because a certain elevation angle is usually required to maintain level flight for most airplanes.
2. Click the Level Calibration button on the Sensor tab of the configurator to start the calibration. The whole calibration process will take you several seconds and the LED will blink blue rapidly during calibrating. Do not move the airplane until the calibration is done.
3. After a successful calibration, the result will be saved and displayed on the screen, you can adjust them manually in the future. If you get a rapid red blinking during calibration, this means the result exceeds the maximum permissible value (i.e. ±25deg), in this case, you have to re-install the gyro to reduce the deviation caused by installation.

As a same reason, a hover calibration is recommended to perform after installation if you want to fly with HOVER mode. The procedure is quite similar to that of level calibration. The only difference is that the airplane should be lifted vertically to the ground instead of putting it on the ground in Step 1.

Quick Calibration
After finishing the first step, you can also perform the calibration using the button without connecting the gyro to a PC or a programming card.

• To start the level calibration, press and hold the button for about 2 seconds, release the button once the LED turns solid White.
• To start the hover calibration, press and hold the button more than 4 seconds until the LED starts to flash White continuously.

ACCELEROMETER CALIBRATION

Each gyro has been carefully tested and calibrated before leaving the factory. Usually, you do not need to perform a calibration for the accelerometer again. However, in some specific cases, we would suggest you re-calibrate the accelerometer to obtain better performance, these include temperature changes those will probably cause the mechanical characteristics changes of the sensor, or replacement of a new sensor, etc. The calibration should be done on a horizontal desktop and the gyro needs to be removed from the airplane first.

Calibration Procedure
Connect the gyro to the PC and wait until the initialization is done. Open the configurator and go to the Sensor -> Accelerometer Calibration tab, click the Calibrate button. Follow the prompts and complete the next 2 steps corresponding to both side of Z axis of the unit, do not move the gyro while calibrating at each step.

OTHER SETTINGS

Stick Deadband
The stick dead band is the range around the very center of the sticks at where the gyro will not react. Some transmitters have the problem that when the sticks are brought back after an input, they are not exactly at the same center position as before which may generate a deviation on the corresponding function, in this condition, you can increase the setting of stick dead band to fix it. The adjustment range of the dead band is 0% to 20%, the default 5% is fit for most radios without modification.

Servo Frequency
Set the working frequency for the servos. The analog servos can only work with 50Hz, a high frequency may cause damage of the servos. Check the servo specifications before increasing the setting, if you don’t know what the maximum update rate that is tolerated by your servos never use more than 50Hz. In theory, the higher the working frequency of the servos the better performance of the gyro can be obtained, but it may increase the power consumption and cause heating of the servos. This setting will affect all output channels including THR.

Gain Level
Change the level of the basic gain, the default “Medium” is fit for most airplanes.

Control Behavior
After installing the gyro, the airplane will become more stable but less responsive because of the correction of the gyro. To improve we need to reduce the correction strength of the gyro on the desired direction dynamically when there is an input of the sticks. This function allows you to change the control behavior by choosing different curves of the gain attenuation.

PROGRAMMING

To setup the gyro, download and install the latest HobbyEagle A3 Configurator and the USB driver from our website at https://www.hobbyeagle.com/a3-configurator/

• The software supports Windows XP, Windows 7, Windows 8 and Windows 10 (32 or 64 bit).
• If the installation fails, please download and install Microsoft .NET Framework 4 first.
• Install the USB driver (CP210X_VCP) before connecting the gyro to the PC.

Related Documents

• Installation Guide:  https://www.hobbyeagle.com/a3-configurator/docs/installation_guide_en.pdf
• USB Driver Installation Guide:  https://www.hobbyeagle.com/a3-configurator/docs/usb_installation_guide_en.pdf
• Quick Start Guide:  https://www.hobbyeagle.com/a3-configurator/docs/quick_start_guide_en.pdf
• Firmware Update Guide:  https://www.hobbyeagle.com/a3-configurator/docs/firmware_update_guide_en.pdf

SPECIFICATIONS

• Main Controller: 32-bit MCU
• Sensors: High-precision 3-axis gyroscope and 3-axis accelerometer
• Gyroscope Scale Range: 2000dps
• Accelerometer Scale Range: 4g
• PWM: 800 ~ 2220uS, Neutral 1500/1520uS, 50Hz ~ 333Hz
• Input Voltage: DC 3.6V ~ 8.4V
• Operating Temperature: -10 ~ 50
• Size: 30××19.5××7.5mm
• Weight: 4.8g (excluding wires)

References

• HobbyEagle - HobbyEagle Electronic Technology Co., Ltd.

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