- ALPHA status. - Multitasking ability with run-time command executions
for real-time control and feedback. - Decelerating feed hold and resume
during operation. - System abort/reset, which immediately kills all
movement and re-initializes grbl. - Re-structured grbl to easily allow
for new features: Status reporting, jogging, backlash compensation. (To
be completed in the following releases.) - Resized TX/RX serial buffers
(32/128 bytes) - Increased planner buffer size to 20 blocks. - Updated
documentation.
- Fixed the planner TODO regarding minimum nominal speeds. Re-arranged
calculations to be both more efficient and guaranteed to be greater
than zero. - Missed a parenthesis location on the rate_delta
calculation. Should fix a nearly in-perceptible issue with incorrect
acceleration ramping in diagonal directions. - Increased maximum dwell
time from 6.5sec to an 18hour max. A crazy amount more, but that's how
the math works out. - Converted the internal feedrate values to mm/min
only, as it was switching between mm/min to mm/sec and back to mm/min.
Also added a feedrate > 0 check in gcode.c. - Identified the long slope
at the end of rapid de/ac-celerations noted by stephanix. Problem with
the numerical integration truncation error between the exact solution
of estimate_acceleration_distance and how grbl actually performs the
acceleration ramps discretely. Increasing the
ACCELERATION_TICKS_PER_SECOND in config.h helps fix this problem.
Investigating further.
- Serial functions contained quite a few modulo operations that would
be executed with high frequency when streaming. AVR processors are very
slow when operating these. In one test on the Arduino forums, it showed
about a 15x slow down compared to a simple if-then statement. -
Clarified some variable names and types and comments.
- Update grbl version and settings version to automatically reset
eeprom. FYI, this will reset your grbl settings. - Saved
3*BLOCK_BUFFER_SIZE doubles in static memory by removing obsolete
variables: speed_x, speed_y, and speed_z. - Increased buffer size
conservatively to 18 from 16. (Probably can do 20). - Removed expensive!
modulo operator from block indexing function. Reduces significant
computational overhead. - Re-organized some sqrt() calls to be more
efficient during time critical planning cases, rather than non-time
critical. - Minor bug fix in planner max junction velocity logic. -
Simplified arc logic and removed need to multiply for CW or CCW
direction.
- Significant improvements in the planner. Removed or reordered
repetitive and expensive calculations by order of importance:
recalculating unchanged blocks, trig functions [sin(), cos(), tan()],
sqrt(), divides, and multiplications. Blocks long enough for nominal
speed to be guaranteed to be reached ignored by planner. Done by
introducing two uint8_t flags per block. Reduced computational overhead
by an order of magnitude. - Arc motion generation completely
re-written and optimized. Now runs with acceleration planner. Removed
all but one trig function (atan2) from initialization. Streamlined
computations. Segment target locations generated by vector
transformation and small angle approximation. Arc path correction
implemented for accumulated error of approximation and single precision
calculation of Arduino. Bug fix in message passing.
