DAGU robot arm with object Tracking

Robot Arm with Object tracking Sensor. The IR eye is used as an Object detection and tracking sensor. For more details about the eye see: https://www.robotshop.com/letsmakerobots/node/11293. The robot arm will try to keep the distance between the sensor and the object fixed. Based on the data received from the four IR sensors the controller will decide the suitable position of the servo motors to keep the distance between the sensor and the object fixed. The controller used for this project is the Wild thumper controller board. for more details about the controller see: https://www.robotshop.com/letsmakerobots/node/24368.

Tracks moving objects

  • CPU: atmega168
  • Power source: 12V 3A
  • Sensors / input devices: IR compound eyes

This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/dagu-robot-arm-with-object-tracking

What is the project?

If it was to buy an arm and set it on a table, you can click the “finished” box.

Could we get a bit more here? Description of the project, controller used, what it is going to do, programming method, any sensors, a video of the arm working, some assemby pictures --we will take really anything here.

On this topic…

If you’re using the stock controller, how did you fare with it? I’m looking to use one myself and could use a bit of knowledge…

project proposal

the project is to use camera as vision sensor. it is required to design a new controller so that the arm will be directed toward objects in real 3-D space through the camera pictures ( which is 2-D space)…

Unfortunately DAGU send the old controller by mistake

Unfortunately  DAGU send the old controller by mistake. I run this controller but it is not really good. i expect to get the new controller from DAGU in the next week. After receiving the good controller i will finish the mechanical fixing ( since it is not very stable) and start the project step by step.

horizontal position with load

the arm in horizontal position. the current is increased due to arm weight.

13012011015.jpg

the arm in horizontal position. the current is increased largely because the lower servo must move to the other end but it could not do that because the servo power  could not counter the arm weight.

13012011016.jpg

cost

@oddbot:How much does this arm costs ?

:in my best australian

:in my best australian accent:

Well mate, I don’t think OB sets pricing for his goods, but here’s a spiffy place you can buy a DAGU arm to throw in your boot…

https://www.robotshop.com/dagu-6-degrees-of-freedom-robotic-arm.html

the new controller

I got the new controller last week. however i could not install the software in the CD. it is not working neither in my laptop with windows vista) nor in my desktop( with windows XP sp2). when i tried direct commands it works fine,  so i wrote my own software in VB script running on excel sheet.

the overall current drawn is higher than before and the servo speed is very high.

 

phase #1

Phase #1 of this project is to build the required software that guide the robot arm to specified position in 3-D space. this software will depend on inverse kinematic  equations to estimate the joints angles. then, a lookup table will be used to find the required servos pulse widths.

 

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the Grip

if it is required to set accurate position of the robot arm then the Grip length must be calculated in term of grip width. The Grip used in this arm is from DAGU.The grip mechanism uses a scissor action to open and close the gripper, so the grip length changes depending on the grip width. The relationship of length to width was determined to be a third order polynomial( see https://www.robotshop.com/letsmakerobots/node/24441):

y = -0.0181x3 + 0.0557x2 - 0.2001x + 10.64  

where, y; is the Grip length and x is the grip width

The 6 servos and the angles

The Dagu robot arm has 6 DOF ( 6 servos). they are:

  1. Base Servo
  2. Shoulder Servo
  3. Elbow Servo
  4. Wrist Servo
  5. Hand Servo
  6. Grip Servo

 

Range of Motion

 Servo motors are controlled by pulse-width modulated signals that control the position of the servo actuator. Servo pulse widths vary from 500 to 2500 microseconds, which corresponds to a servo rotation angle of approximately 0° to 180°. A pulse width of 1500 microseconds will set the servo at the neutral position, or 90°. The range of motion and direction of travel for the servos used in the DAGU arm are summarized below:

Elbow.jpg

wrist_servo.jpg

hand_servo.jpg

Grip Servo

grip_servo.jpg

 

 

The Robot is now finished

The Robot is now finished and tested. Any comments and/ or suggessions are welcomed.

 

lol

seems like a scared little animal lol

Hi friend, I like your robot

Hi friend, I like your robot I need some imformation about it please. What do you think about your robot? Is it a good robot? have any problem? I need buy one, but im not sure. I know is a DAGU robot, but in robotshop.comm someone said they have a very high rate of failure and the gripper and wrist are especially susceptible. Please help me I need to know If you recommend me this robot, I want to teleoperate the robot with a sensorised glove (acelerometers and gyroscopes).

Sorry about my english, im from ecuador.

well, if you are asking

well, if you are asking about the Robot Arm platform, it is cheap one (low price compared with others) also it sufferes from many design problems. i do not recomend it for researches or education. it maybe ok for hobbies and demos.

i could not understand your requirements exactly, but it may not be the correct choice for you. the following are some of the problems:

the platform body is heavy.

the joints is not exactly fitted.

no ballbearings used.

the length of the grip is long compared with the length of the forarm (this could be the worst thing)

the rotating base is not correctly designed.

my platfrom is currently broken and is not working anymore!!

thanks you, it is all i need

thanks you, it is all i need to know, well you have cleared my doubts. I must find another robot for my applicacion because I need precision. I want to control a robot arm with the movements of my arm using a glove with acelerometers and gyroscipes. What do you think will be the best robot arm for my application? Its only for research proyect I need a small one like yours. Thank you again my friend.

AL5D Robotic Arm from Lynxmotion

you are welcom :slight_smile:

The AL5D Robotic Arm from Lynxmotion could be a good choice for you. ( http://www.lynxmotion.com/p-816-al5d-robotic-arm-combo-kit-free-software.aspx) or order the version without the controller.

you may need to change the controller board in order to add the accelerometers and gyros. you can select one of the arduino based boards.