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Patching the SR6 firmware

Patching the SR6 firmware file​

If you use the SR6, you may need to patch the firmware to prevent a bug from happening.

info

The following only applies if you use the SR6 robotic arm.

Patch​

At line 429 of SR6-Alpha5_ESP32.ino, in the SetPitchServo function, replace the following line:

  float beta = acos((csq + 5625 - bsq)/(150*c)); // Angle between c-line and servo arm

with this:

  float beta = acos(constrain((csq + 5625 - bsq)/(150*c), -1, 1)); // Angle between c-line and servo arm

Then, upload the firmware to your device using the instruction manual of your SR6.

Reason​

During development of this software, it was discovered that the firmware has a bug that causes an invalid number to be sent to the servo motors.

This bug happens when the robotic arm is instructed to move to an unusual position, which could realistically be reached in the virtual space.

This incorrect instruction will cause the servo motors to respond incorrectly by moving to an extreme position.

For this reason, if you use the SR6, I recommend you to patch the firmware.

note

For the technical reason: A value greater than 1, such as 1.153 is passed to the acos function. This returns NaN.

This probably indicates that the inverse kinematics solver within the firmware has a mistake in it.