BBB Serial Debug

Just a quick Note

• J1 = GND (Ground)
• J2 = CTS
• J3 = VCC (5V)
• J4 = RXD (Receive Data)
• J5 = TXD (Transmit Data)
• J6 = RTS

And its pin map

Compiling uROSnode

uROSnode
We can find it on Github: https://github.com/openrobots-dev/uROSnode
It is a great work for MCU can run ROS.
https://dl.dropboxusercontent.com/u/2771793/uros/doc/html/pag_demos.html
One great explainition about this project: pdf
ROSCon: http://vimeo.com/66970254

Problem 1:
Compiling ./src/urosUser.c
In file included from ../../include/urosUser.h:45:0,
                 from ./src/urosUser.c:42:
./src/urosUser.c: In function 'urosUserParamUpdate':
./src/urosUser.c:353:21: error: 'UrosRpcParam' has no member named 'class'
     urosError(paramp->class != UROS_RPCP_INT, return UROS_ERR_BADPARAM,
                     ^
../../include/urosBase.h:323:50: note: in definition of macro 'urosError'
 #  define urosError(when, action, msgargs) { if (when) { action; } }
                                                  ^
./src/urosUser.c:368:21: error: 'UrosRpcParam' has no member named 'class'
     urosError(paramp->class != UROS_RPCP_INT, return UROS_ERR_BADPARAM,
                     ^
../../include/urosBase.h:323:50: note: in definition of macro 'urosError'
 #  define urosError(when, action, msgargs) { if (when) { action; } }
                                                  ^
./src/urosUser.c:383:21: error: 'UrosRpcParam' has no member named 'class'
     urosError(paramp->class != UROS_RPCP_INT, return UROS_ERR_BADPARAM,
                     ^
../../include/urosBase.h:323:50: note: in definition of macro 'urosError'
 #  define urosError(when, action, msgargs) { if (when) { action; } }
                                                  ^
make: *** [build/obj/urosUser.o] Error 1
Fix:
Find the struct in uROSnode/include/urosRpcCall.h

typedef struct UrosRpcParam {

  uros_rpcparamclass_t      pclass;      /**< @brief Parameter pclass.*/

  union {

    UrosString              string;     /**< @brief XMLRPC string.*/

    int32_t                 int32;      /**< @brief XMLRPC int/i4.*/

    uros_bool_t             boolean;    /**< @brief XMLRPC boolean.*/

    double                  real;       /**< @brief XMLRPC double.*/

    UrosString              base64;     /**< @brief XMLRPC base64.*/

    void                    *mapp;      /**< @brief XMLRPC struct (map pointer).*/ /* TODO */

    struct UrosRpcParamList *listp;     /**< @brief XMLRPC array (list pointer).*/

  }                         value;      /**< @brief Parameter value.*/

} UrosRpcParam;

Then, just change the variable name from class to pclass. The error seems caused by typo.

Problem 2:
/src/lld/lwip/uros_lld_conn.c:784: undefined reference to `netconn_set_sendtimeout'

At first, I think it seems the lwip version caused error.

Change from 1.4.0 to 1.4.1

However, problem still exist.

/../../ext/lwip/src/api/api_lib.c:627: undefined reference to `sys_now'

build/obj/api_msg.o: In function `do_writemore':

/home/kv/rosnode/ChibiOS_2.5.1/demos/uROSnode/demos/turtlesim-chibios+lwip/../../../../ext/lwip/src/api/api_msg.c:1228: undefined reference to `sys_now'

collect2: error: ld returned 1 exit status

make: *** [build/turtlesim.elf] Error 1

Fix:

Then i just do the dirty thing. That I comment sys_now in 

lwip/src/api/api_msg.c

and 

lwip/src/api/api_lib.c

cause they have no instance.

Finally, the compilation is d
one.

st-flash write build/turtlesim.bin 0x08000000

2014-06-19T16:29:51 INFO src/stlink-common.c: Starting verification of write complete

2014-06-19T16:29:54 INFO src/stlink-common.c: Flash written and verified! jolly good!

But it doesn't Run! Obviously, we have different hardware module with their. 

The difficulty then will be porting the peripheral to the STM32F407 which we using Discovery.

I think porting this could be a great help to my robot!

DC Motor Speed PID Control with Arduino

It is a new MechLab for NCKU ME next semester, a PID controller!
Hardware:

• Arduino Mega2560
• Motor Shield: Dual H-brigde VNH2SP30
• Due to there is no lib of this shield, I modify the dual-vnh5019 Lib to fit the goal
• Github: https://github.com/kvzhao/DualVNH2SH30MotorShield

• DC Motor - IG42
• I also write a C++ wrapper for this motor, utilizing Encoder lib(also a little modify for constructor) and VNH2SP30 lib
• Github: https://github.com/kvzhao/DCMotorIG42

Source Code on Github: https://github.com/kvzhao/ME-PIDLab

The crucial part of the PID code is listed below

void loop()
{
    // Run a period to estimate more precise speed
    Motor.Tick();
    // Run for one Second
    delay(SamplingTime);
    Motor.Tock();

    // Read rotation speed from Encoder
    Input = Motor.getSpeedRPS();

    // PID Compute
    PID_Controller.Compute();
    if ((Output-prevOutput) >= oscGap) {
      //Output = prevOutput;
    }
    Motor.setSpeed(Output);
    prevOutput = Output;
    // Show Data
    /*
    Serial.print("Input: ");
    Serial.println(Input);
    Serial.print("Setpoint: "); 
    Serial.println(Setpoint);    
    Serial.print("Error: ");
    Serial.println(error);
    Serial.print("Output: "); 
    Serial.println(Output);*/
    Serial.println(error);
    // wait a little while
    delay(5);
}

My first test result (with KP=98, KI=8, PD=5)

There is almost no steady state error, however overshoot happens.

Next step is to tune the parameters and control the motor smoothly!

Some useful references

• http://www.robotroom.com/PWM5.html
• http://www.precisionmicrodrives.com/application-notes-technical-guides/application-bulletins/ab-012-driving-vibration-motors-with-pwm
• http://lancet.mit.edu/motors/motors3.html
• http://mechatronics.mech.northwestern.edu/design_ref/actuators/motor_theory.html
• http://www.roadtocreate.com/?tag=vnh2sp30
• http://www.pololu.com/product/537

MathJax Test

Refer to this article: 用 MathJax 顯示數學符號－以 Blogger 為例

a simple test \[F = ma\]

Ypcto Project

參考 ：Tutorial from ROS.org 

• Ypcto Project
• Yocto Project 是一個協助建立 Linux 嵌入系統的專案，Yocto 專案包含建立客製 Linux 發行版本的各種工具。
• Intel Galileo initial Yocto image install

C your Arduino in different way

Articles about programming Arduino with pure C.

• Arduino in C
• Program Arduino with AVR-GCC
• Programming Arduino Uno in pure C

Good tool for building Arduino in  command-line mode.

• Ino

ps. Arduino build process

Good articles about Arduino and IMU

Kalman filter is the one of the filter, or signal processing technique that lures me.

I wanna make a small system (via Arduino) to implement it and act as the lab material of embedded system tutorial.

Some useful websites and source code listing here :

• Arduino 5 min tutorial -- IMU 
• A practical approach to Kalman filter and how to implement it
• TKJ Eelectronics's Github

Besides, here is the Arduino PID lib.

Great article : Faster analogRead()