Azurit Firmware (English)

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This page describes how to flash the Arduino for your robot mower, configure the robot mower and look for errors.

Test requirements

Warning.pngSecurity note: For security reasons, always remove mower blades in your first tests!

Warning.pngImportant: For your first wheel motor tests, jack your robot so that the tires can run freely without ground contact!

Uploading the Arduino code to your Arduino

NOTE: If you have never worked with Arduino before, read our 'Arduino first steps' introduction (it also contains useful information if uploading does not work).

1. Download an Ardumower Release at Github

2. Download the Arduino IDE that we will use to upload the code to your Arduino

3. Start Arduino IDE, and choose the right Arduino board (either Mega 2560 or Due (recommended) - for Due: choose 'USB programming port')

4. In file 'mower.h', choose the correct PCB (PCB_1_2 or PCB_1_3) - Example for choosing PCB 1.3 (a line started with // will be ignored):

// #define PCB_1_2    
#define PCB_1_3

5. In file 'mower.h', choose the correct robot type (ROBOT_ARDUMOWER or ROBOT_MINI)

6. In file 'mower.h', choose the correct motor drivers (DRIVER_MC33926 or DRIVER_L298N) - in most cases, DRIVER_MC33926 is the correct one

7. If you do not want the robot to monitor battery and charging voltage, set 'batMonitor = 0' in mower.cpp.

8. Upload the code to your Arduino board

Settings

The robot uses settings that you can adjust for your own robot and environment (via the code or via pfod App). The default settings (factory settings) are stored in the config file 'mower.cpp'. In this file you can find descriptions for all settings.

After you modified any settings via serial console or via pfod App, these settings have higher priority. However, you can go back to default settings (or any uploaded settings) by a factory reset.

Warning.png Important: If you upload a new Firmware version into your robot and you do not want to use any old/modified settings, you have to reset all settings (via pfodApp: 'Settings->Factory reset' or via console 'main menu->load factory settings'), so any uploaded settings take place.

Serial console

After successfully uploading, open the Arduino IDE serial console and choose baud rate 19200. You should see something like this. If all you get is an error line instead, please read the troubleshooting section.

ADCMan: found calib data
---ADC calib---
ADC sampleRate=38462
AD0	min=9999	max=-9999	diff=-19998	ofs=334
AD1	min=9999	max=-9999	diff=-19998	ofs=417
...
SETUP
matchSignal size=24
subSample=4
capture size=192
1	0	-1	0	1	-1	1	-1	0	1	-1	1	0	-1	0	1  -1	0	1	-1	0	1	0	-1	
IMU error: no calib data
--------
accOfs=0.00,0.00,0.00
accScale=2.00,2.00,2.00
comOfs=0.00,0.00,0.00
comScale=2.00,2.00,2.00
--------
initL3G4200D
gyro read error
gyro read error
gyro read error
loadSaveErrorCounters: read
loadSaveErrorCounters addrstop=423
loadUserSettings
EEPROM USERDATA: NO EEPROM USER DATA
PLEASE CHECK AND SAVE YOUR SETTINGS
loadSaveRobotStats: read
loadSaveRobotStats addrstop=822
START
Ardumower 1.0a8-Azurit-dev  PCB 1.3  Arduino Mega  IOREF=5.00
Robot: Mini
press...
 d for menu
 v to change console output (sensor counters, values, perimeter etc.)
sen_counters
t     1 L  0 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat 677.0 chg 677.0  0.0 imu  0 adc  0 Mini

Motor test

In this motor test we will make sure that the motors are controlled in the right direction.

Warning.pngImportant: For your first wheel motor tests, jack your robot so that the tires can run freely without ground contact!

1. In Arduino IDE serial console, press 'd' and ENTER to get the main menu - you should see something like this:

MAIN MENU:
1=test motors
2=test odometry
3=communications menu
5=calibrate IMU acc next side
6=calibrate IMU com start/stop
7=delete IMU calib
8=ADC calib (perimeter sender, charger must be off)
9=save user settings
c=test RTC
l=load factory settings
r=delete robot stats
x=print settings
e=delete all errors
0=exit

2. Press '1' and ENTER for motor test. Motors left and right should turn in the shown directions.

testing left motor (forward) half speed...
t   741 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   742 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   743 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   744 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   745 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
testing left motor (reverse) full speed...
t   747 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat   6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   748 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   749 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   751 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   752 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat   6.8 chg  0.1  0.9 imu  0 adc  0 Mini
testing right motor (forward) half speed...
t   754 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   755 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   756 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   757 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   758 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat   6.8 chg  0.1  0.9 imu  0 adc  0 Mini
testing right motor (reverse) full speed...
t   760 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   761 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   762 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   763 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini
t   764 L5790 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.1  0.9 imu  0 adc  0 Mini

If the wrong motor is turning, exchange left and right motor wires. If one motor is not turning in the right direction, exchange the motor wires (+/-).

Odometry

1. Make sure that you have connected all motor odometry cables to your PCB. Now we will test the encoders and connections. In the main menu (see above), choose '2' to test odometry. Both left and right odometry counters should start to increase about the same speed like shown below:

Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=0  right=0
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=1  right=1
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=2  right=1
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=3  right=2
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=4  right=3
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=6  right=4
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=7  right=5
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=8  right=6
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution, '0' exit  left=9  right=7
...

Slightly block one wheel with your hands to see if the correct odometry counter (left or right) is reducing speed. If the wrong side is reducing speed, exchange odometry cables.

2. Choose 'o' to test a full wheel revolution. The wheels should make one turn and stop about at the starting position like shown below (in this example I'm using an Ardumower Mini and PCB1.3):

Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=0  right=0
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=0  right=1
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=1  right=1
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=1  right=2
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=2  right=2
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=3  right=2
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=3  right=3
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=4  right=3
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=4  right=4
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=5  right=4
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=5  right=5
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=6  right=5
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=7  right=5
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=7  right=6
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=8  right=6
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=8  right=7
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=9  right=7
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=9  right=8
Press'f' forward, 'r' reverse, 'z' reset, 's' stop, 'o' one revolution  left=10  right=8

3. Choose '0' and ENTER to get back to the main menu.

First run

After motor test and odometry test were successful, we can do a first test run.

Warning.pngImportant: For your first robot test, jack your robot so that the tires can run freely without ground contact!

To start the mower, you need to add a button and a buzzer. There are several modes (you have to press and hold the button for x beeps long):

1 beeps : Normal mowing (using blade modulation if available)
2 beeps : Normal mowing (without blade modulation)
3 beeps : Drive by model remote control (RC)
4 beeps : Drive without mowing
5 beeps : Find perimeter and track it

Press the button for '1 beep', and the robot's wheels should start turning forward (switching from state OFF to state FORW) as shown below:

t     2 L5731 m0 OFF  rpm    0    0 set    0    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.3  0.9 imu  0 adc 97 Mini
t     0 L5942 m0 FORW rpm    0    0 set   50   50 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.3  0.9 imu  0 adc  0 Mini
t     0 L5942 m0 FORW rpm   60   60 set   50   50 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.3  0.9 imu  0 adc 90 Mini
t     1 L3764 m0 FORW rpm   60   60 set   50   50 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.3  0.9 imu  0 adc 97 Mini
t     2 L4160 m0 FORW rpm   60   60 set   50   50 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat  6.8 chg  0.3  0.9 imu  0 adc 97 Mini

If it does not stay in the 'FORW' state for at least one minute, probably a sensor will make a false trigger and you have to fine-tune the settings for that sensor.

Sensor counters and sensor values

There are different views for your sensors:

m0  - sensor trigger counters  (default view)
m1  - current sensor values 
m2  - perimeter values​​

You can change the view by pressing 'v' and ENTER. You will see the selected view in the console as shown below:

t     4 L177 m0  ...

There is a counter for each sensor. Once a sensor triggers, the corresponding counter increases. In the example below the mower motor current overflow triggered, and so the mower motor sensor counter increases. Additionally, the robot switches from state 'FORW' (forward) to the new state 'REV' (reverse):

t     4 L177 m0 FORW spd   33   33    0 sen    0    0    0 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat 20.8 chg 21.7  0.0 imu  0 adc  0 Ardumower
t     5 L177 m0 REV  spd  -26  -26    0 sen    0    0    1 bum    0    0 dro    0    0 son   0 yaw   0 pit   0 rol   0 bat 20.8 chg 21.7  0.0 imu  0 adc  1 Ardumower


Here is a description of each column:

t   - time of current machine state (FORW, REV, ROLL, etc.) (ms)
L   - loop () - cycles per second  
m   - console output mode (0 = sensor trigger counters / 1 = current sensor values ​​/ 2 = perimeter values​​)  
spd - current motor speed left and right wheels
set - set point values for motor wheels speed control
sen - motor current overflow counter:  left wheel, right wheel, mower motor
bum - bumper counter: left, right 
son - ultrasonic distance-below: counter 
pit, roll - inclination (calculated with IMU/accel sensor) 
yaw - compass course 
bat - battery voltage 
chg - charger voltage sensor

Console commands

You can manually trigger sensors via the console. Also, you can set the robot into a specific state.

'd': menu for testing, adjust IMU, Bluetooth
'v': monitorMode (show Value not Counter
'h': drive home
'p': track perimeter
'l': simulate left bumper
'r': simulate right bumper
's': simulate lawn sensor
'm': toggle mower motor
'c': simulate charging
'+': rotate 90 degrees 
'-': rotate 90 degrees
'3': activate model RC
'0': OFF
'1': Automode motorMowEnable

Bluetooth module

Ardumower live monitoring configuration debugging.jpg

The Ardumower can be monitored and controlled via an Android device (phone/tablet). Before you can use the Android App, you have to configure the bluetooth module on the robot so it matches the baud rate in the robot code (mower.h).

1. Plug-in the bluetooth module (HC-05) on the PCB at the position where the bluetooth module pinout matches the PCB pinout.

2. Press and hold the micro KEY button on the bluetooth module while powering-on the PCB (and bluetooth module). The bluetooth LED should blink slowly now.

3. Start the Arduino IDE serial console, choose 19200 baud and press 'd' and ENTER to enter the main menu.

4. Press '3' and ENTER to get into the communications menu - you should get something like this:

COMMUNICATIONS MENU  == Bluetooth ==
 1=Select other communication method
 2=setup BT module config (quick baudscan (recommended))
 3=setup BT module config (extensive baudscan)
 0=Main Menu

5. Press '2' and ENTER to run the bluetooth module config - you should see several 'success' lines as shown below:

trying baudrate 38400 config 0...
send: AT
send: AT
 received: OK
=>success
detecting BT type...
send: AT+VERSION
send: AT+VERSION?
 received: +VERSION:2.0-20100601
OK
=>must be a HC03/04/05 ?
setting name Mini...
send: AT+NAME=Mini
 received: OK
=>success
setting pin 1234...
send: AT+PSWD=1234
 received: OK
=>success
setting baudrate 19200...
send: AT+UART=19200,0,0
 received: OK
=>success
You may restart BT module now!

6. After the module has been properly configured, re-power (power off and on) the PCB (or bluetooth module).

7. Download the App 'ArduRemote' on your Android device. Alternatively, you can use the App 'pfodApp'.

8. You need to pair the bluetooth module it with your Android device. On the Android device, choose symbol "Settings" (via Android menu). Now choose "Wirless and Networks->Bluetooth Settings" and "Find device". Finally, choose "pair with this device" and enter your pin ("1234"). The Bluetooth module should now appear as "paired". Try to connect using ArduRemote App with your robot. You should get a menu like this on your Android device:

Arduremote ardumower.png

In the serial console on your PC, you should see the commands sent from your Android App:

Pfod cmd= {.}

PC/Mac remote control application

In addition to the Android App, we have developed a remote control application for PC/Mac/Linux (developed in Processing/Java). The Mac standalone version has to be created within Processing, the Windows version is already available as standalone version:

  1. Download Windows 64 bit executable and extract it:

https://drive.google.com/uc?export=download&confirm=EYiA&id=0B90Bcwohn5_HRFFMUUFYWF9OdW8

  1. Download and install Java runtime (version 8 or higher): https://java.com/de/download/
  2. Plug-in an USB bluetooth dongle on your PC
  3. In Windows, pair the USB bluetooth dongle with the Ardumower bluetooth module - two new serial ports will be created on your PC (the first for incoming bluetooth connections, the 2nd one for outgoing bluetoth connections)
  4. Run 'processing_remote.exe', all available serial ports will be shown - select the serial port for outgoing connections

The code for Processing can be found here: https://github.com/Ardumower/ardumower/tree/master/code/Test_und_Entwicklung/processing_remote

Processing can be downloaded here: https://processing.org/

Sensor logging

For PC data analysis, algorithm modelling and optimization, you can collect robot sensor data using pfodApp like this:

  1. Using your Android pfodApp, connect to your robot and choose 'Log sensors'. The logged sensor data will be displayed. Click 'Back' to stop logging (NOTE: for ArduRemote, press Android menu button before and choose 'Enable logging' to enable file logging).
  2. Connect your Android phone to the PC, if being asked on the phone choose 'Enable as USB device', so you phone shows as a new Windows drive on your PC.
  3. On your PC, launch Windows Explorer and choose the new Android drive, browse to the 'pfodAppRawData' folder (for ArduRemote: 'ArduRemote' folder), and copy the data file to your PC (you can identify files by their Bluetooth name and date).

Motor controller (PID)

The speed of the motors is controlled by a software PID controller. You can monitor the quality of the motor speed control via pfodApp (Plot->Motor control):

Charging

The battery voltage can be monitored (Battery->Monitor->YES). So it can be determined when the robot should go to the charging station. Via charging contacts, the robot can detect if has reached the charging station.

Via pfodApp (Android) you can monitor the charging process.

Timer/RTC

1. For time-controlled mowing the RTC module should work successfully. Test the RTC module by entering the main menu (press 'd' and ENTER) and then press 'c' and ENTER for the RTC test:

MAIN MENU:
1=test motors
2=test odometry
3=communications menu
5=calibrate IMU acc next side
6=calibrate IMU com start/stop
7=delete IMU calib
8=ADC calib (perimeter sender, charger must be off)
9=save user settings
c=test RTC

During this test, a test date will be written to the RTC module and read back. The read back date should match the test date. This indicates the RTC module works successfully.

2. To activate time-based mowing, set 'Timer->Use->YES' (via Android pfodApp), set the current date and time, and define one or more timers.

Important: If you activate 'GPS->Use->YES', the current date and time will be set via GPS and not via RTC clock.

On the robot, several timers can be programmed (via Android pfodApp). For each timer, you can define a time interval ('time windows') for the desired days. As long as the actual time is within any time window, the robot can freely mow, charge, mow, charge etc.

Example:

Timer 1: 08:00 - 13:00 Monday, Thuesday, Wednesday

Timer 2: 14:00 - 16:00 every day

Timer 3: off

Timer 4: off

IMU

An IMU (Intertia Measurement Unit) is a key component of an inertia navigation system. We use it to:

  • detect if the robot is in tilt orientation
  • keep the robot on track for the 'lane-by-lane' mowing pattern

Slope1.png

Acceleration sensor

An acceleration sensor measures earth gravity force (m*s^2) in all 3 robot axes (x/y/z) allowing you to calculate the orientation towards earth center of the robot (Roll, Pitch). However, it cannot detect movement around Yaw - this requires a gyro.

Ardumower pitch roll yaw.png

Gyro

A gyro measures rotational speed (degree/second) in all 3 robot axes (Roll, Pitch, Yaw). This allows us to correct the robot if it is driving 'off-course' due to wet conditions or slope. When integrating (adding) gyro values over time, the actual course (yaw) can be calculated. However, because each sensor reading has a small error, the course will 'drift' over time. This needs to be corrected via an absolute heading sensor (compass).

Typical gyro measurement errors:

                noise dps/sqrt(Hz)
L3G4200D        0.03
ITG3200         0.03
L3GD20          0.03
BMG160/BNO055   0.014
MPU9250         0.01
L3GD20H         0.011
LSM9DS0         0.00875
BMI160          0.007  
MAX21003        0.007
L2G2IS/L2G3IS   0.006
MPU9150/MPU6050 0.005
ADXRS290        0.004
CRM100/200      0.003
GYPRO2300       0.00277

Compass

If a robot drives on a wet lawn, you'll notice quickly that it will not drive straight forward, but instead tends to drive into the direction of the slope. Reading a compass heading can solve this problem and the robot will drive straight forward again .

However, a compass has two problems:

  1. If tilting the robot, the compass measurements (x,y,z) relate to the tilted robot. So, you need to correct them using knowing the tilt angles. This requires the use of the accerlation sensor (x,y).
  2. The compass measurements are influenced by motors. So you may need to switch of the motor to get an accurate measurement.

Typical compass measurement errors:

                        sensitivity (uT)       typical heading error (degree)
AK8975 (MPU9150)        0.3                    5
BNO055                  0.3                    2.5
CMPS11 (9S0 2413 530BS)                        2.0
HMC5883L (GY-80)        0.2                    1.5
AK8963 (MPU9250)        0.15                   not tested
LIS3MDL                 0.14                   not tested
LSM303DLM
MAG3110/FXOS8700CQ      0.1                    not tested

IMU sensor fusion

To eliminate the issues of all sensor, they are merged to compute the course (degree) and pitch/roll angles.

We use a complementary filter to fusion all sensor values.

Ardumower sensor fusion.png

IMU module

GY-80

  • Acceleration sensor: ADXL345B
  • Compass sensor: HMC5883L
  • Gyro: L3G4200D
  • Pressure sensor: BMP085 (not used here)

Assembly

This photo shows how the IMU module is placed in the driving position (the red arrow shows the driving position). Ensure a minimum distance of 30cm from all motors. This minimum distance seems to be needed to ensure the compass is not disturbed by dynamically disturbing sources (like motors).

Imu assembly.png

IMU calibration steps

Acceleration sensor

This calibration can be performed outside of the robot. Place each of the 6 module sides exactly upright, do not move and choose 'next side calibration':

  • Via serial console "IMU acc calibration next side" OR
  • Via pfodApp "Settings->IMU->acc calibration next side"

Do not move the module during the measurement of each side! During measurement you will hear a short beep tone.

Repeat this step for all 6 sides. After all 6 sides are calibrated, you will hear a short melody.

Gy80 acc calibration.png

Compass sensor

This calibration can only be performed inside of the robot (IMU in its final position). Start the compass calibration:

  • Via serial console "IMU com calibration start/stop" OR
  • Via pfodApp "Settings->IMU->com calibration start/stop"

Hold each of the 6 module sides to North direction and tilt the module until minimum and maximum of the axis does not change anymore (until no tone is outputted anymore):

Gy80 com calibration.png

Calibration quality test

For a quality test, you can plot the calibration results (Yaw, Pitch, Roll) via pfodApp. Place the robot on a flat ground and let it rotate (pfodApp: click on "Commands->Auto rotate" until robot rotates). Alternatively, you can let the robot drive a circle (pfodApp: click "Manual->Right" until it drives the desired radius). Finally, choose 'Plot->IMU' to see the calibration result.

For the yaw plot, the curve should be a straight line when the robot is rotating with a constant speed.

Ardumower imu plotting.jpg

Perimeter receiver

1. Azurit Firmware supports one coil. Connect the perimeter receiver (LM386 module output pin) to PCB pin 'PerimeterLeft', and mount the coil centered at the front in upright position as shown in the drawing.

2. Then activate the perimeter in the Ardumower software (pfodApp->Options->Perimeter Use: YES). It is recommended to keep the default perimeter settings.

The perimeter settings are:

  • Timed-out if below smag (timedOutIfBelowSmag) - default setting: 300 | If smag below this value, sender is considered as off (perimeter timeout appears)
  • Timeout (s) if not inside (timeOutSecIfNotInside) - default setting: 8
  • Trigger timeout (perimeterTriggerTimeout) - default setting: 0 | Perimeter outside trigger timeout when escaping from inside (ms)
  • Perimeter out roll time max (perimeterOutRollTimeMax) - default setting: 2000 | Max (random generator) roll time after perimeter out (ms)
  • Perimeter out roll time min (perimeterOutRollTimeMin) - default setting: 750 | Min (random generator) roll time after perimeter out (ms)
  • Perimeter out reverse time (perimeterOutRevTime) - default setting: 2200 | Time to drive reverse after perimeter out (ms)
  • Perimeter tracking roll time (perimeterTrackRollTime) - default setting: 1500 | Hit obstacle while tracking: roll time
  • Perimeter tracking reverse time (perimeterTrackRevTime) - default setting: 2200 | Hit obstacle while tracking: reverse time
  • Transition timeout (trackingPerimeterTransitionTimeOut) - default setting: 2000 | Max. time required for a in/out transition during tracking, robot will start rotating after this timeout
  • Track error timeout (trackingErrorTimeOut) - default setting: 10000 | Max. time required for a in/out transition during tracking, robot will go into error after this time
  • Track_P (perimeterPID.Kp) - default setting:51 | Perimeter PID "P" setting
  • Track_I (perimeterPID.Ki) - default setting:12.5 | Perimeter PID "I" setting
  • Track_D (perimeterPID.Kd) - default setting:0.8 | Perimeter PID "D" setting
  • Use differential signal (useDifferentialPerimeterSignal) - default setting: YES | Use differential signal (see signal section)
  • Swap coil polarity (swapCoilPolarity) - default setting:NO
  • Block inner wheel (trackingBlockInnerWheelWhilePerimeterStruggling) - default setting: YES | robot is wheel-spinning while tracking => roll to get ground again

Receiver ADC calibration

Warning.png Before the perimeter receiver can be used, the ADC pin has to be calibrated. The ADC calibration ensures that the zero point (silence) is detected correctly, and so later the received signal is symmetric around zero.

  1. The perimeter sender and robot motors must be switched off during calibration!
  2. If you cannot avoid that another sender is disturbing during calibration, remove the coil during calibration (connect LM386 input line to GND)
  3. Run the ADC calibration once ("pfodApp->ADC Calibration" or via serial console 'main menu->ADC calib')

When calibrated correctly, the signal in the pfodApp plot ('sig') should be around zero (0) when the perimeter sender is switched off. When the perimeter sender is switched on, the plotted signal ('sig') should have the same maximum amplitude for both positive and negative axis (is 'symmetric around zero').

Receiver diagnostics/troubleshooting

The receiver signal, filter result and signal quality can be monitored via Android phone (pfodApp->Plot->Perimeter):

Plot signal description:

sig:  coil signal (raw pulse sequence after ADC) - it's a short snapshot (32 samples), and it's taken every 20 seconds 
      (so you need to wait 20 seconds for the next snapshot)
mag:  filter result: inside (negative) or outside (positive), magnitude: distance to perimeter wire/magnetic signal strength (RSSI)
      - this is used for perimeter tracking
smag: filter result, low-pass filtered, without sign (smooth mag) - this is used for 'sender-off' detection
      The threshold can bet set via pfodApp (Settings->Perimeter->Timed-out if below smag)
in:   binary result, low-pass filtered: inside (1) oder outside (0) - this is used for perimeter boundary detection
      If the robot is not inisde for a certain time, it will go into error. The threshold can bet set via pfodApp
      (Settings->Perimeter->Timeout (s) if not inside)
cnt:  number of "inside-outside" transitions (counter)
on:   perimeter sender active, robot is inside and smag is high enough (1) or inactive/outside/smag too low (0)
qty:  signal quality (how distinguisable inside and outside were in filter result
      computes ratio:  match score with template signal / match score with inverse template signal              
      1.0 means poor quality, you should get 1.5 or higher)

The 'mag' plot should be clear (without spikes): Inside the perimeter loop, the signal should be a clear negative curve, outside it should be a clear positive curve. If your 'mag' curve is not clear (and has spikes), try to troubleshoot/optimize:

  • Verify, your coil is connected correctly at 'pinPerimeterLeft' (you still may get a poor signal when connected at a wrong Arduino pin!)
  • Decrease the threshold for a smag timeout via 'pfodApp->Options->Perimeter->Timed-out if below smag'
  • Reverse coil if the in/out is inverted or reverse the perimeter wire
  • Minimize cable length between coil and LM386-pre-amplifier (directly mount coil onto pre-amplifier)
  • Increase distance between coil and mower motor/DC converter (move away coil 30cm or more from any motors or DC converters)
  • Add some magnetic shield (e.g. your battery) between coil and motors/DC converter

Tracking of perimeter

The tracking of the perimeter wire is performed using a (software) digital PID controller. The controller's parameters (P,I,D) can be configured via the phone (pfodApp).

You can find more information about PID controllers here: Forum.

GPS

With the help of a GPS receiver (e.g. GY-NEO6MV2, ublox 6m), the long-term position can be calculated. Therefore, the GPS position values will be averaged.

Currently, GPS is used

  • to receive current date and time

Visualization of GPS data

GPS data (course, speed, position etc.) can be plotted by pfodApp. One neat thing I discovered is that you can get precise heading and speed even when moving short distances (< 2m). This works because the GPS receiver is evaluating the signal phase due to the doppler effect.

hdop    measurement error indication (the more satellites are from different directions, the lower the error)
sat     number of satellites in view
spd     ground speed m/s
course  ground course degree
alt     altitude meter
lat     latitude
lon     longitude

GPS error

Typical GPS error is 2-5 meters (at a sample rate of 1 Hz). As this is not sufficient as a replacement for a perimeter wire, GPS can only be seen as an extension or for global navigation (navigation from one lawn to another lawn).

Drop sensor

Einstellung im Sketsch:

Die Absturzsensoren sind ab der Softwarefunktion 242 integriert.

(Eine Integration in die Handy App bzw. das persönliche Speicher der Einstellungen ist zur Zeit noch nicht Intrigiert.)

Der Anschluss des linken und rechten Absturzsensor sind an den Pin 45 und 23 vorgesehen.

Um die Funktion zu aktivieren sind folgende Einstellungen in der Mower.ccp vorzunehmen.

//  ------ drop -----------------------------------
 dropUse          = 1;     // has drops?  -Dropsensor - Absturzsensor vorhanden 0-nein  1-Ja
 dropcontact      = 1;     //contact Kontaktausführung 0-Öffner 1-Schließer  

Verdrahtung:

Die IR Sensoren sollten möglichst weit vorne vor den Rädern angebracht werden. Um evl Reichweiten Schwankungen zu vermeiden sollten sie vor fremd Licht geschützt werden. Die IR Sensoren sollten so eingestellt werden das diese im normalen Betrieb leuchten, und wenn man den Mover hochhebt ausgehen. Am besten gleich auf der Grasoberfläche testen oder dort zumindest gegebenenfalls nachjustieren. In der Seriellen Ausgabe kann man den richtigen Anschluss kontrollieren. Sollte der Mover im Normalbetrieb den Kontakt zur Oberfläche haben sollte der Dropsensor nicht ausgelöst sein bzw der Counter des Dropsensors sollte nicht hochgezählt werden. Fall das so nicht sein sollte, ist die Einstellung in der Mower.ccp Datei zu kontrollieren bzw. zu ändern.

Dropcontact = 1;      ändern in 0

(Kann je nach verwendeten Sensoren anders sein) Danach den Mower anheben so das dieser den Kontakt zur Oberfläche verliert. Darauf hin sollte in der seriellen Konsole sichtbar sein das der Dropsensor ausgelöst hat bzw. der Counter hoch zählt. Darauf hin kann das ganze im automatischen Betrieb getestet werden.

Gegebenenfalls muss noch die Acceleration angepasst werden. Diese ist auch in der Mower.ccp Datei zu finden. Das ist die Beschleunigungszeit bzw. die Abbremszeit der Antriebsmotoren. Dieser Wert muss angepasst (erhöht) werden damit der Mower schnell genug an der Gefahrenstelle anhalten kann.


Finite state machine

This section describes some internals of the Ardumower software architecture. Kurz zum Ablauf der Software: In der Hauptschleife (loop) werden periodisch:

  1. Die Sensoren eingelesen (readSensors)
  2. Der Zustandsautomat durchlaufen und abhängig vom aktuellen Zustand die Sensorwerte überprüft (CheckXXXXX) und von den Sensorwerten in neue Zustände gewechselt (setNextState) - beim Wechsel werden ggf. neue Soll-Werte für die Motoren gesetzt (Beispiel: motorLeftSpeedRpmSet).
  3. Die Motoren mit den Soll-Werten angesteuert (motorControl)

Die möglichen Zustände und Ergebnisse für die Übergänge des Zustands-Automaten sind hier unten alle grafisch darsgstellt.

Wenn der Mower also im Zustand FORWARD ist, fährt er nach vorn. Man schaut also in der loop() nach was alles in diesem Zustand FORWARD gemacht wird (case FORWARD). Dort hätte man die Möglichkeit weitere Aktionen einzufügen.


Main component of the software is a so called 'finite state machine', that means there exists a set of states ("OFF", "FORWARD", "ROLL", etc.) that the robot can be in. Depending on events (sensor is triggering etc.), the robot will enter a new state.

State diagram (Note: The drawing has been created using draw.io)

Ardumower Statemachine.png

Implemented updates:

  • If obstacle during reverse => roll
  • If obstacle during roll => forward


How to report a new bug/new feature/new code

Click on 'this link' and create a new issue - Please let us know:

   Your platform version (Arduino Mega 2560, Arduino Due)
   Your Arduino IDE version (latest code requires 1.6.3)
   Your exact operating system (Windows 8, Linux etc.)
   Your Ardumower code version (for a list of releases see https://github.com/Ardumower/ardumower/releases)
   Any other information that may be useful...

Diagnostics/troubleshooting

Sensor errors

Each time a sensor triggers, its corresponding sensor counter increases. The sensor trigger counters as well as the current sensor values can be viewed on the serial console. The following values are shown for the trigger counters in the serial console:

  1. Time of state machine's state (ms)
  2. loop()-counts per second
  3. choosen Verbose-Mode (0=counter readings/1=current values/2=current values)
  4. current state machine state (FORW, REV, ROLL etc.)
  5. drive home? (1/0)
  6. "spd" - Control/speed motors: left (PWM), right (PWM), mower (RPM)
  7. "sen" - Current limit exceeded counter motors: left, right, mower
  8. "bum" - bumper counter: left, right
  9. "son" - Ultrasonic-distance threshold exceeded (counter)
  10. "pit/roll" - Tilt (computed by acceleration sensor)
  11. "com" - compass course
  12. "per" - Perimeter loop detected: counter
  13. "bat" - Battery voltage
  14. "chg" - Charging current

Using the key 'v', you can toggle between sensor trigger counters and current sensor values.

Warning.png Additionally, you can use pfodApp (Android) to plot the sensors (trigger counters and current values) over time. This allows you to wirelessly monitor your robot mower for error diagnostics. It is highly recommended.

Hardware measurements

For detecting failures in the assembly or electronic parts, it is highly recommended to use an oscillscope (e.g. pocket oscillscope DSO201) for your measurements. An Oscilloscope allows you to detect short-time failures in power signals, perimeter sender and receiver signals, odometry signals and more.

Dso201.jpg

Tutorial for pocket oscilloscopes: http://www.ardumower.de/index.php/de/forum/anleitungen-hilfe/142-bedienung-oszilloskop-dso201

Error codes

If your robot beeps periodically (every 5 sec one short beep), it is in ERROR state. Either run the serial console or 'pfodApp->Error Counters' to find out the detailed error. The possible solutions for each error are given below. For details about your robot settings, see Settings.

 ERR_CPU_SPEED           CPU speed error
                         * Check I2C cables (e.g. reduce wire length)
 ERR_MOTOR_LEFT          Left gear motor error
                         * Check gear motor driver module and left gear motor (supply voltage, signal lines)
                         * MC33926: ensure SLEW jumper is not set
                         * Tracking: reduce Motor-Max-PWM and Tracking-P to reduce EMF
 ERR_MOTOR_RIGHT         Right gear motor error
                         * Check gear motor driver module and right gear motor (supply voltage, signal lines)
                         * MC33926: ensure SLEW jumper is not set
                         * Tracking: reduce Motor-Max-PWM and Tracking-P to reduce EMF
 ERR_MOTOR_MOW           Mower motor error 
                         * Check mower motor driver module and mower motor (supply voltage, signal lines)
                         * MC33926: ensure SLEW jumper is not set
                         * Reduce Motor-Max-Power, so over-current is detected earlier
 ERR_MOW_SENSE           Mower motor over-current 
                         * Check mower motor driver module and mower motor
                         * Increase Motor-Max-Power, so over-current is detected later
 ERR_IMU_COMM            IMU communication error 
                         * Check IMU module connections
 ERR_IMU_CALIB           IMU calibration error
                         * Start IMU calibration (either via Console or pfodApp->Settings->IMU)                     
 ERR_IMU_TILT            IMU tilt error
                         * Check IMU module and robot orientation
 ERR_RTC_COMM            RTC communication error 
                         * Check RTC module connections, RTC battery etc.
 ERR_RTC_DATA            RTC corrupt data error
                         * Set and save RTC date and time
                         * If the error repeats, change RTC battery
 ERR_PERIMETER_TIMEOUT   Perimeter signal timeout 
                         * Check perimeter sender, wire etc.
                         * Check coil polarity
                         * Reduce Perimeter-smag, so timeout is higher
                         * Increase Perimeter-timeout-seconds, so timeout is higher
                         * Check your signal-to-noise ratio is higher than 1.0
 ERR_TRACKING            Perimeter tracking error 
                         * Check perimeter sender, wire etc.
                         * Increase Perimeter-tracking-timeout, so timeout is higher
 ERR_ODOMETRY_LEFT       Left motor odometry error 
                         * Check left odometry cable
                         * Check left motor direction
 ERR_ODOMETRY_RIGHT      Right motor odometry error 
                         * Check right odometry cable
                         * Check right motor direction
 ERR_BATTERY             Battery error 
                         * Check battery connections
 ERR_CHARGER             Charger error 
                         * Check charger connections 
 ERR_GPS_COMM            GPS communication error 
                         * Check GPS cables
 ERR_GPS_DATA            GPS data error 
                         * Check GPS antenna and cable
 ERR_ADC_CALIB           ADC calibration error 
                         * Start ADC calibration (either via Console or pfodApp->ADC calibration)
 ERR_EEPROM_DATA         EEPROM data error 
                         * Save user settings (either via Console or pfodApp->Settings-Save)

After fixing the error, you can delete errors:

Console:
press...
d for menu
e=delete all errors

I2C errors

If you get an error in the console ('I2C bus error. Could not clear. SCL clock line held low'), the I2C bus is not working properly. Reasons can be: RTC module is missing or a general I2C bus error.

Ensure the I2C bus is working correctly. A console stucked at line 'initL3G4200D' indicates I2C is not working correctly. If there's a communication problem or another serious problem, the error counter increases. The error counter can be monitored via pfodApp. Additionally, the robot mower will beep when started.

Several components (Arduino Nano, RTC, IMU, etc.) are communicating via the I2C bus (SDA/SCL wires). These wires should be very short (maybe even twisted) and they should be far away from DC converter and motor drivers. If there's a communication problem, the error counter will increase and robot will beep when started. The error counter can be monitored via pfodApp.

Arduino errors

If your Arduino is running slowly or completely hanging, check odometry and I2C connections. Sporadic spikes on these lines can make the Arduino running slowly.

Disable all pins not connected

Ensure that you have disabled all features and pins in the robot configuration that are not connected (not used).

Example: If you do not have connected odometry pins, disable them in the robot config (robot.cpp):

odometryUse       = 0;       // use odometry?

Motors working correctly

Run the serial console (Arduino IDE: CTRL+SHIFT+M, 19200 Baud) and press 'd' and ENTER for menu. Then press '1' and ENTER to run the motor test.

Any unexpected sensor triggering

If your robot does something unexpected, it might be a sensor that is incorrectly triggering. Check this via the serial console:

Run the serial console (Arduino IDE: CTRL+SHIFT+M, 19200 Baud), and start the robot. Each time a sensor triggers, the counter of that sensor will increase. See description of each sensor below. Now when your robot does something unexpected, have a look which of the sensor counters increased to locate the problem.

Some sensor not triggering?

...

Bluetooth not connecting?

  • Verify that BT module baudrate is configured properly (using Ardumower Console) - activate programming button on BT module for programming procedure.
  • Verify that BT module is 'paired' on your Android phone
  • Verify that Arduino Mega is not powered via USB (but DC/DC instead)

Robot not stopping to rotate when reaching perimeter (home mode)

At first, verify that the perimeter tracking itself is working: Manually put the robot on the perimeter wire, and via ArduRemote App, choose 'Commands->Track' and verify the robot is tracking the perimeter. If it does not, adjusting the tracking PID parameters may help.

The position of the coil should be as indicated here:

If the robot runs over the perimeter wire (coil is then "outside" of perimeter loop) it will try to get "inside" the loop again by rotating. If getting the coil "inside" the loop by rotating is not possible, the robot will rotate endless.

The more the robot runs over the perimeter, the more difficult it is to get "inside" again by rotation. The robot speed should be reduced as well as moving the coil further outside.

NOTE: It's always a good idea to manually place the robot at the position where you saw the robot detecting the perimeter. The perimeter plot should change from "in" to "out" at that position (http://wiki.ardumower.de/index.php?title=Perimeter_wire#Receiver_diagnostics.2Ftroubleshooting). Then manually rotate the robot (without motor) at that position and verify that "out" changes again to "in". If that is not the case, the position of the coil is not OK or the robot drives too quickly and detects the perimeter too late.

More troubleshooting

  1. Änderungen der Konfigurationseinstellungen in der Mower.cpp Datei werden nicht übernommen
  2. Der Ladestrom im ArduMower zeigt nichts oder falsche Werte an
  3. Der Perimetersender ohne automatische Regelung
  4. Elektrische Fehlersuche am BT Modul
  5. Programmieranleitung für das Bluetooth Modul auf der Platine V1.2