Inaccuracy of cutting edge

Issue

The cutting edge deviates significantly from the benchmark coordinates when checking the accuracy of the cutting edge.

(The difference from the control point is large in the cutting edge position measurement.)

*The allowable value of the cutting edge accuracy is ±5 cm from the benchmark coordinates.

Answer

Please use the following to determine when your current problem is occurring.

Please refer to “Common Confirmation Items” and read the contents according to each event.

• Incident immediately after delivery/moving to the site, or switching to a different system → Refer to 1.
• Incident during continuous normal use → Refer to 2.
• Incident during calibration→ Refer to 3.

Common Confirmation Items

Cause	Action
・Is the measurement position of the cutting edge correct?
The measurement position of the cutting edge is wrong.	[Influence on horizontal accuracy (rule)] ・Check that the actual cutting edge position (left, middle, right) being measured and the cutting edge position set on the screen (left, middle, right) are aligned. ・Check that the coordinate values in the control points used for confirmation are correct and that there are no selection errors. [Tap the bucket icon] →[Select the control points] →[Check the bucket tip L/M/R] →check the difference value

・Is the satellite acquisition environment secure?

Is there an unobstructed sky above the GNSS antenna?

[Affects accuracy in all directions, both horizontal and vertical (irregular)] ・If there are any devices that block the GNSS antenna, make sure they are not blocking the GNSS antenna. ・Work in areas free of high-voltage power lines, etc. nearby. ・Work in a location where the sky above the GNSS antenna is unobstructed by forests, valleys, etc. *If the GNSS antenna's sky coverage is low, the number of satellites acquired may decrease and the accuracy of the cutting edge may not be achieved. It can be checked from the status (Green/Good → Red/Poor)

・Is the correction information set appropriately?
VRS Appropriate mount point is not selected or not set (When using Ntirp)	[Affects accuracy in all horizontal and height directions (irregular) Error indication
Is the baseline distance too far? (When using Ntrip/radio)	[Affects accuracy in all horizontal and height directions (irregular)] ・If using Ntrip, work within 10 km of the recommended baseline distance. [GNSS Settings] → [GNSS Info] ・In case of using a radio, it depends on the specification of the radio. *The farther the distance from the electronic reference station/fixed station, the less stable the accuracy tends to be.
Fixed station setting and installation location are not appropriate. (When using Ntrip/radio)	[Affects accuracy in all horizontal and height directions (irregular)] ・Set appropriate correction information format. ・There is a difference between the fixed station installation location and the input of the known point coordinates. ・Review the environment in which the fixed station is installed (is there anything obstructing the sky above the antenna?)

・Is the data set appropriate (is there a localization file)?
Localization data is not appropriate	[Affects accuracy in all horizontal and height directions(rule)] *Review whether the horizontal and vertical error is within the threshold (usually, the threshold is 10 to 30 mm). How to check [Project File] → [Coordinate System].

1.Incident immediately after delivery/moving to the site, or switching to a different system

・Calibrated bucket not used
Bucket file not set Bucket calibration not yet performed	All buckets used for 3DMG must be calibrated (datamined). A bucket file must be selected for the actual bucket to be used. ［Touch the bucket icon］→［ Bucket File Settings］
Coupler (A-lock, B-lock) is installed.	Calibration requires measurement including the coupler. Check the calibration results to see if the measurements are correct. ［Tap the bucket icon］ → ［Touch the edit icon of the currently selected bucket］

・The fixed station setting location and settings are different or the reception settings on the 3DMG side are incorrect.
The location of the fixed station setting has been changed	・It is necessary to check the reference point installation and confirm whether there is any difference between the fixed station setting and the reference point. Please check the common confirmation items above. 3DMG(Ntrip) ・It is necessary to check if appropriate mounting points are used. 3DMG（Digital radio） ・Need to be confirmed, including the reception of the receiver

２ Incident during continuous normal use

・Edge wear is not taken into account
The cutting edge is worn out from the beginning	If the cutting edge is worn out, the tooth length in the bucket data needs to be changed. ［Tap the bucket icon］ → ［Touch the edit icon for the currently selected bucket］ How to change the length of the worn out tooth

・Matching function has not been deactivated.
Matching of the cutting edge is in progress.	It is necessary to check if matching has been used for a long period of time. Please deactivate the matching function and then check the cutting edge accuracy again. Icon is lit yellow → Matching is in use [Tap the bucket icon] →[Select the control point] →[Check the bucket cutting edge L/M/R] →[Check the difference value.] Is matching activated within the offset?

・The value of the cutting edge is not stable.
There is a variation in the value of the cutting edge confirmation.	・With the cutting edge stationary, check if there is variation in the value of each sensor that is being calculated. ［Menu］→［Machine Calibration Settings］→［2D/3D Accuracy Check］ ・Either the bucket, arm, or boom in the 3DMG tablet screen is spinning in a circular motion. Please inform the distributor where you purchased the product of the issue

３Incident during calibration

・Mismeasurement of bucket link length
Mistake between measured value and input value of bucket link	Please reconfirm whether there is any discrepancy between the actual measurement and the input value of the link length at the time of calibration.

・Mismatch between each dimension and input value at the time of calibration

Misalignment between the measured length and the actual measured value and offset value for each part

Check if there is any discrepancy in the four-position measurement due to the misalignment of values at the time of calibration. Recommendation　 Point the construction equipment to the north to check the point of cutting edge confirmation and the values obtained from the 4 postures. If it is not possible to point the machine to true north, please perform the measurement in the other 3 orientations. Please keep the compared values. If there is a difference between the values of the construction machine and the calibration values, the difference will occur when you check the values of the cutting edge accuracy.