The EEROS Education Robotics Platform

User Tools

Site Tools

You are here: EEDURO Delta Robot » Calibrating the Delta Robot
calibration

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
Last revisionBoth sides next revision
calibration [2019/07/19 16:11] – visentincalibration [2019/08/14 14:52] – visentin
Line 1: Line 1:
-====== Initialization - Zero reference ====== +===== Calibrating the Delta Robot ===== 
-The ''Calibration Sequence'' can be started by triggering the safety event ''doCalibrating''. This can be done by pressing the red button until this lights up. Press and hold the red button for 2 seconds, this will trigger the Safety Event ''doCalibrating''. When finished with calibrating, press the red button once again. Press the green button to get back in normal operation mode.+If you need to calibrate the positions of the blocks for the Delta robot follow this steps: 
 +  - The Delta robot has to be powered up and running 
 +  - If the Delta is not in it's homing position: 
 +     - Press the blue button to stop the normal operating mode 
 +  - Else: 
 +     - Press the green and blue button together 
 +  - Remove all plates
  
 +You have to calibrate the Delta with each plate. Start with plate 0 -> that means no plate is used, and position 0.
 +  - Put the actual plate to the actual position and move the TCP to the center of this position.
 +  - Hit the blue button.
 +  - Move the TCP inside the gap of the current block only in x and y direction.
 +  - Hit the blue button again.
 +  - If the actual position is number 3 go to the next step. Else increment the position number and start again with step 1.
 +  - If the actual plate is number 3 you are finished. Else use the plate with the next higher number and start again with step 1.
  
-==== Mechanical Limits of the Axis Motors ==== +If you have calibrated all blocks on every position, put all blocks back and press the blue button. The Delta will move to it's homing position.
-The axis motors have mechanical upper and lower limits. +
- +
-=== Upper limit === +
- +
-|{{:delta:zero_ref_ntb.jpg?400|}}|{{:delta:zero_ref_ntb_2.jpg?300|Upper limit calculation detail}}|  +
-|Upper limit calculation shown below| Upper limit calculation detail | +
- +
-L = 17.5 \\ +
-B = 15   \\ +
-s = 4    \\ +
- +
-The upper limit can be calculated as follows: +
-\\ \\ +
-//(1) tan(β) = sin(β)/cos(β) = (B-y)/L// \\ +
-//(2) cos(β) = s/y// \\ +
-\\ +
-Substitute (2) into (1) to get: \\ +
-\\ +
-//(3) L*sin(β)-B*cos(β)=-s// \\ +
-\\ +
-Using following trigonometric formulas in (3):  +
-\\ \\ +
-//(4) t = tan(β/2) // \\ +
-//(5) sin(β) = 2*tan(β/2)/(1+tan^2(β/2) // \\ +
-//(6) sin(β) = (1-tan^2(β/2)/(1+tan^2(β/2) // \\ +
-\\ +
-Leads to: +
-\\ \\ +
-//(7) (s+B)*t^2 + 2*L*t + (s-B) = 0// \\ +
-\\  +
-Solutions are:  +
-\\  +
-// t1 = 0.2736 -> β = 30.6°// \\ +
-// t2 = -2.1157 (neg. solution)// \\ +
-\\  +
-Hence, the maximum angle the axis can turn is // 90° + β ≅ 120°//.\\ +
-\\  +
-=== Lower limit === +
- +
-|{{:delta:motor-axis-calculation-lower-n.jpg?300|}}| +
-|Lower limit of the Axis Motor | +
- +
-Lower limit of the Axis Motor measured on the Delta robot, γ is about 5°. +
- +
-==== Mechanical Limits of the Tool Center Point Motor ==== +
-The TCP rotation is also limited by two metall pins. The maximum turn angle is calculated as follows:\\ +
-{{ :delta:tcp-limit.jpg?300 |TCP limit}} +
- +
-//sin(γ/2) = r/R//\\ +
-//γ=2*arcsin(r/R)= 0.0600 (rad) = 3.438°//\\ +
-\\ +
-That is the value for one side. The other side is identical, so the maximum turn angle is\\ +
-\\ +
-//β = 2*PI - 2 * 0.06 = 6.16 (rad) ≅ 353°//.+