Chess Robot - Set Up

Gunnar86 · May 9, 2021, 1:53am

Are there any python libraries I can import from the AL5d code?

geraldinebc15 · May 10, 2021, 4:44pm

Not a library per se but there are some sample codes:

Python:

Lynxmotion/Arms/blob/master/Code examples/Python (RPi)/Basic 2D IK example/lib_al5_2D_IK.py

# 2017-07-12 by scharette
# Basic 2D IK example of AL5 + Python (library)

from math import sqrt, atan, acos, fabs

# Define legnth of AL5 sections
# if AL5A
#A = 3.75;
#B = 4.25;

#if AL5B
#A = 4.75;
#B = 5.00;

#if AL5D
A = 5.75;
B = 7.375;

# Constants
rtod = 57.295779	# Radians to degrees constant

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Arduino:

github.com

Lynxmotion/Arms/blob/master/AL5D/Arduino_Arm/Arduino_Arm.ino

    #include <Servo.h>
    #include <PS2X_lib.h>

  #define SOUND_PIN    5        // Botboarduino JR pin number
  #define PS2_DAT      6        
  #define PS2_CMD      7
  #define PS2_SEL      8
  #define PS2_CLK      9

    PS2X ps2x;
    int error = 0;
    byte type = 0;

    #define Deadzone 10

    char ArmSize = 'D'; // Must be 'A', 'B', or 'D'  DO NOT REMOVE THE SEMICOLON OR THE ' '
    float A;
    float B;
    float rtod = 57.295779;

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PS: @Solomon123 is also working on modifying the code to work with the AL5D so you may want to reach out to him.

dancrissco · July 4, 2022, 9:29pm

I am having a Math Domain Error after the first manual move

geraldinebc15 · July 5, 2022, 2:12am

Hello @dancrissco!

Did you set the dimensions in inches? If you did make sure it is possible to reach the desired position with the arm.

For reference these are the dimensions I used:

{“baseradius”: 1.77, “cbFrame”: 0.62, “sqSize”: 1.09, “cbHeight”: 0.79, “pieceHeight”: 1.97}

dancrissco · July 5, 2022, 7:56am

Thanks for your reply Geraldine.
I had my cbframe as 10 inches.
What is cbframe?
I thought it was one side of chess board. My mistake.
Here are my parameters
{“baseradius”: 2.0, “cbFrame”: 10.0, “sqSize”: 1.25, “cbHeight”: 1.0, “pieceHeight”: 1.5}
Regards
Daniel

geraldinebc15 · July 5, 2022, 4:27pm

cbframe means chessboard frame, so in this case, it would be what is marked in red:

dancrissco · July 5, 2022, 7:32pm

Hi Geraldine. It is working now. I made a few chess moves to check it out. Will now work on it to make the movement smooth and repeatable. Once again thanks for the help.

cbenson · July 5, 2022, 7:50pm

@dancrissco We hope you might be up to providing a video of your progress here! Happy it’s working!

dancrissco · July 13, 2022, 12:26pm

The chess robot works well for about three moves and then comes with an invalid move announcement.
This happens after I have moved the chess piece. Kindly advise.
Screen shot of the code area is provided. Is this vision related?

geraldinebc15 · July 13, 2022, 12:52pm

A nice way to find out if this is what is happening is by adding some lines to the code you screenshotted to show the "prevIMG and “curIMG”. However, it is most likely that the picture is being taken when your hand is on the chessboard, please make sure that you wait until the robot is resting in its place, make your move, and press the clock when your hand is not on the way.

Let me know if that works

dancrissco · July 13, 2022, 2:01pm

Thanks Geraldine. I will try that.
Regards
Daniel

dancrissco · July 13, 2022, 4:21pm

Hi Geraldine, the issue is when the robot picks the Bishop or Knight. It misses or topples adjacent pieces.
This causes the invalid move
The picking of pawns is clean. Wondering if I should play with gripper angle or open close?
I think the key now may be to master the robot pick and place.
Any suggestions?

tepalia02 · July 14, 2022, 7:34am

Thanks for the detailed tutorial. Must try someday.

geraldinebc15 · July 14, 2022, 8:33pm

Wondering if I should play with gripper angle or open close?

Yes, that’s a good idea.

You could also try making the arm go lower or higher. You can find that part of the code here:

github.com

Robotics-Technology/Chess-Robot/blob/master/ArmControl.py#L187

    
      
                  x = params["baseradius"] + params["cbFrame"] + params["sqSize"] * sqNumber - params["sqSize"]*1/2

                  y = params["sqSize"] * sqletter - copysign(params["sqSize"]*1/2,sqletter)

          

              return(x,y)

          

          def executeMove(move, params, color, homography, cap, selectedCam):

          

              allMotors.setColorLED(lssc.LSS_LED_Cyan)

              z = params["cbHeight"] + params["pieceHeight"]

              angles_rest = (0,-1155,450,1050,0)

              gClose = -2

              gOpen = -9.5

              goDown = 0.6*params["pieceHeight"]

              gripState = gOpen

              x, y = 0, 0

              

              for i in range(0,len(move),2):

          

                  # Calculate position and FPC

                  x0, y0 = x, y

                  x, y = CBtoXY((move[i],move[i+1]), params, color)

github.com

Robotics-Technology/Chess-Robot/blob/master/ArmControl.py#L219

    
      
          # Go down

          shoulder.setFilterPositionCount(15)

          elbow.setFilterPositionCount(15)

          angles_BSEWG2 = LSS_IK([x, y, z - 1 - goDown, gripState])

          print("2) GO DOWN")

          arrived2,issue2 = LSSA_moveMotors(angles_BSEWG2)

          askPermision(angles_BSEWG2, arrived2, issue2, homography, cap, selectedCam)

          

          if (i/2)%2: # Uneven move (go lower to grab the piece)

              gripState = gOpen

              goDown = 0.6*params["pieceHeight"]

          else:       # Even move (go a little higher to drop the piece)

              gripState = gClose

              goDown = 0.5*params["pieceHeight"]

          

          # Close / Open the gripper

          gripper.moveCH(int(gripState*10), 500)

          time.sleep(1)

          print("3) CLOSE/OPEN the gripper\n")

          

          # Go up

dancrissco · July 15, 2022, 6:14pm

Thanks Geraldine. Will try.

dancrissco · July 15, 2022, 8:29pm

Video - LinkedIn

dancrissco · July 15, 2022, 8:30pm

I have posted a video of the Chess Robot in Linkdin. Opened the gripper and it is better now. Still work to be done but happy with progress so far.

cbenson · July 18, 2022, 12:18pm

Appreciate the video! I thought pawns could only move forward by one space?
Someone’s idea of adding magnets underneath seems quite good to re-center each piece.

geraldinebc15 · July 19, 2022, 4:13pm

Opened the gripper and it is better now.

Awesome! Looks great with the eyes

I thought pawns could only move forward by one space?

They can move two spaces on their first move

dialfonzo · July 19, 2022, 6:43pm

Very nice project…!!