2 This file is part of Smoothie (http://smoothieware.org/). The motion control part is heavily based on Grbl (https://github.com/simen/grbl).
3 Smoothie is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
4 Smoothie is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
5 You should have received a copy of the GNU General Public License along with Smoothie. If not, see <http://www.gnu.org/licenses/>.
8 #include "libs/Module.h"
9 #include "libs/Kernel.h"
10 #include "libs/nuts_bolts.h"
17 #include "libs/StreamOutputPool.h"
18 #include "StepTicker.h"
26 #define STEP_TICKER_FREQUENCY THEKERNEL->step_ticker->get_frequency()
27 #define STEP_TICKER_FREQUENCY_2 (((double)STEP_TICKER_FREQUENCY)*STEP_TICKER_FREQUENCY)
29 uint8_t Block::n_actuators
= 0;
31 // A block represents a movement, it's length for each stepper motor, and the corresponding acceleration curves.
32 // It's stacked on a queue, and that queue is then executed in order, to move the motors.
33 // Most of the accel math is also done in this class
34 // And GCode objects for use in on_gcode_execute are also help in here
47 steps_event_count
= 0;
53 acceleration
= 100.0F
; // we don't want to get divide by zeroes if this is not set
58 recalculate_flag
= false;
59 nominal_length_flag
= false;
60 max_entry_speed
= 0.0F
;
66 acceleration_per_tick
= 0;
67 deceleration_per_tick
= 0;
69 if(tick_info
.size() != n_actuators
) {
70 tick_info
.resize(n_actuators
);
72 for(auto &i
: tick_info
) {
75 i
.acceleration_change
= 0;
76 i
.deceleration_change
= 0;
80 i
.next_accel_event
= 0;
84 void Block::debug() const
86 THEKERNEL
->streams
->printf("%p: steps-X:%lu Y:%lu Z:%lu ", this, this->steps
[0], this->steps
[1], this->steps
[2]);
87 for (size_t i
= E_AXIS
; i
< n_actuators
; ++i
) {
88 THEKERNEL
->streams
->printf("%c:%lu ", 'A' + i
-E_AXIS
, this->steps
[i
]);
90 THEKERNEL
->streams
->printf("(max:%lu) nominal:r%1.4f/s%1.4f mm:%1.4f acc:%1.2f accu:%lu decu:%lu ticks:%lu rates:%1.4f/%1.4f entry/max:%1.4f/%1.4f exit:%1.4f primary:%d ready:%d locked:%d ticking:%d recalc:%d nomlen:%d time:%f\r\n",
91 this->steps_event_count
,
96 this->accelerate_until
,
97 this->decelerate_after
,
98 this->total_move_ticks
,
102 this->max_entry_speed
,
108 recalculate_flag
? 1 : 0,
109 nominal_length_flag
? 1 : 0,
110 total_move_ticks
/STEP_TICKER_FREQUENCY
115 /* Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
116 // The factors represent a factor of braking and must be in the range 0.0-1.0.
117 // +--------+ <- nominal_rate
119 // nominal_rate*entry_factor -> + \
120 // | + <- nominal_rate*exit_factor
124 void Block::calculate_trapezoid( float entryspeed
, float exitspeed
)
126 // if block is currently executing, don't touch anything!
127 if (is_ticking
) return;
129 float initial_rate
= this->nominal_rate
* (entryspeed
/ this->nominal_speed
); // steps/sec
130 float final_rate
= this->nominal_rate
* (exitspeed
/ this->nominal_speed
);
131 //printf("Initial rate: %f, final_rate: %f\n", initial_rate, final_rate);
132 // How many steps ( can be fractions of steps, we need very precise values ) to accelerate and decelerate
133 // This is a simplification to get rid of rate_delta and get the steps/s² accel directly from the mm/s² accel
134 float acceleration_per_second
= (this->acceleration
* this->steps_event_count
) / this->millimeters
;
136 float maximum_possible_rate
= sqrtf( ( this->steps_event_count
* acceleration_per_second
) + ( ( powf(initial_rate
, 2) + powf(final_rate
, 2) ) / 2.0F
) );
138 //printf("id %d: acceleration_per_second: %f, maximum_possible_rate: %f steps/sec, %f mm/sec\n", this->id, acceleration_per_second, maximum_possible_rate, maximum_possible_rate/100);
140 // Now this is the maximum rate we'll achieve this move, either because
141 // it's the higher we can achieve, or because it's the higher we are
142 // allowed to achieve
143 this->maximum_rate
= std::min(maximum_possible_rate
, this->nominal_rate
);
145 // Now figure out how long it takes to accelerate in seconds
146 float time_to_accelerate
= ( this->maximum_rate
- initial_rate
) / acceleration_per_second
;
148 // Now figure out how long it takes to decelerate
149 float time_to_decelerate
= ( final_rate
- this->maximum_rate
) / -acceleration_per_second
;
151 // Now we know how long it takes to accelerate and decelerate, but we must
152 // also know how long the entire move takes so we can figure out how long
153 // is the plateau if there is one
154 float plateau_time
= 0;
156 // Only if there is actually a plateau ( we are limited by nominal_rate )
157 if(maximum_possible_rate
> this->nominal_rate
) {
158 // Figure out the acceleration and deceleration distances ( in steps )
159 float acceleration_distance
= ( ( initial_rate
+ this->maximum_rate
) / 2.0F
) * time_to_accelerate
;
160 float deceleration_distance
= ( ( this->maximum_rate
+ final_rate
) / 2.0F
) * time_to_decelerate
;
162 // Figure out the plateau steps
163 float plateau_distance
= this->steps_event_count
- acceleration_distance
- deceleration_distance
;
165 // Figure out the plateau time in seconds
166 plateau_time
= plateau_distance
/ this->maximum_rate
;
169 // Figure out how long the move takes total ( in seconds )
170 float total_move_time
= time_to_accelerate
+ time_to_decelerate
+ plateau_time
;
171 //puts "total move time: #{total_move_time}s time to accelerate: #{time_to_accelerate}, time to decelerate: #{time_to_decelerate}"
173 // We now have the full timing for acceleration, plateau and deceleration,
174 // yay \o/ Now this is very important these are in seconds, and we need to
175 // round them into ticks. This means instead of accelerating in 100.23
176 // ticks we'll accelerate in 100 ticks. Which means to reach the exact
177 // speed we want to reach, we must figure out a new/slightly different
178 // acceleration/deceleration to be sure we accelerate and decelerate at
179 // the exact rate we want
181 // First off round total time, acceleration time and deceleration time in ticks
182 uint32_t acceleration_ticks
= floorf( time_to_accelerate
* STEP_TICKER_FREQUENCY
);
183 uint32_t deceleration_ticks
= floorf( time_to_decelerate
* STEP_TICKER_FREQUENCY
);
184 uint32_t total_move_ticks
= floorf( total_move_time
* STEP_TICKER_FREQUENCY
);
186 // Now deduce the plateau time for those new values expressed in tick
187 //uint32_t plateau_ticks = total_move_ticks - acceleration_ticks - deceleration_ticks;
189 // Now we figure out the acceleration value to reach EXACTLY maximum_rate(steps/s) in EXACTLY acceleration_ticks(ticks) amount of time in seconds
190 float acceleration_time
= acceleration_ticks
/ STEP_TICKER_FREQUENCY
; // This can be moved into the operation below, separated for clarity, note we need to do this instead of using time_to_accelerate(seconds) directly because time_to_accelerate(seconds) and acceleration_ticks(seconds) do not have the same value anymore due to the rounding
191 float deceleration_time
= deceleration_ticks
/ STEP_TICKER_FREQUENCY
;
193 float acceleration_in_steps
= (acceleration_time
> 0.0F
) ? ( this->maximum_rate
- initial_rate
) / acceleration_time
: 0;
194 float deceleration_in_steps
= (deceleration_time
> 0.0F
) ? ( this->maximum_rate
- final_rate
) / deceleration_time
: 0;
196 // we have a potential race condition here as we could get interrupted anywhere in the middle of this call, we need to lock
197 // the updates to the blocks to get around it
199 // Now figure out the two acceleration ramp change events in ticks
200 this->accelerate_until
= acceleration_ticks
;
201 this->decelerate_after
= total_move_ticks
- deceleration_ticks
;
203 // Now figure out the acceleration PER TICK, this should ideally be held as a float, even a double if possible as it's very critical to the block timing
206 this->acceleration_per_tick
= acceleration_in_steps
/ STEP_TICKER_FREQUENCY_2
;
207 this->deceleration_per_tick
= deceleration_in_steps
/ STEP_TICKER_FREQUENCY_2
;
209 // We now have everything we need for this block to call a Steppermotor->move method !!!!
210 // Theorically, if accel is done per tick, the speed curve should be perfect.
211 this->total_move_ticks
= total_move_ticks
;
213 //puts "accelerate_until: #{this->accelerate_until}, decelerate_after: #{this->decelerate_after}, g: #{this->acceleration_per_tick}, total_move_ticks: #{this->total_move_ticks}"
215 this->initial_rate
= initial_rate
;
216 this->exit_speed
= exitspeed
;
218 // prepare the block for stepticker
226 // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
227 // acceleration within the allotted distance.
228 float Block::max_allowable_speed(float acceleration
, float target_velocity
, float distance
)
230 return sqrtf(target_velocity
* target_velocity
- 2.0F
* acceleration
* distance
);
233 // Called by Planner::recalculate() when scanning the plan from last to first entry.
234 float Block::reverse_pass(float exit_speed
)
236 // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
237 // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
238 // check for maximum allowable speed reductions to ensure maximum possible planned speed.
239 if (this->entry_speed
!= this->max_entry_speed
) {
240 // If nominal length true, max junction speed is guaranteed to be reached. Only compute
241 // for max allowable speed if block is decelerating and nominal length is false.
242 if ((!this->nominal_length_flag
) && (this->max_entry_speed
> exit_speed
)) {
243 float max_entry_speed
= max_allowable_speed(-this->acceleration
, exit_speed
, this->millimeters
);
245 this->entry_speed
= min(max_entry_speed
, this->max_entry_speed
);
247 return this->entry_speed
;
249 this->entry_speed
= this->max_entry_speed
;
252 return this->entry_speed
;
256 // Called by Planner::recalculate() when scanning the plan from first to last entry.
257 // returns maximum exit speed of this block
258 float Block::forward_pass(float prev_max_exit_speed
)
260 // If the previous block is an acceleration block, but it is not long enough to complete the
261 // full speed change within the block, we need to adjust the entry speed accordingly. Entry
262 // speeds have already been reset, maximized, and reverse planned by reverse planner.
263 // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
265 // TODO: find out if both of these checks are necessary
266 if (prev_max_exit_speed
> nominal_speed
)
267 prev_max_exit_speed
= nominal_speed
;
268 if (prev_max_exit_speed
> max_entry_speed
)
269 prev_max_exit_speed
= max_entry_speed
;
271 if (prev_max_exit_speed
<= entry_speed
) {
273 entry_speed
= prev_max_exit_speed
;
274 // since we're now acceleration or cruise limited
275 // we don't need to recalculate our entry speed anymore
276 recalculate_flag
= false;
279 // // decel limited, do nothing
281 return max_exit_speed();
284 float Block::max_exit_speed()
286 // if block is currently executing, return cached exit speed from calculate_trapezoid
287 // this ensures that a block following a currently executing block will have correct entry speed
289 return this->exit_speed
;
291 // if nominal_length_flag is asserted
292 // we are guaranteed to reach nominal speed regardless of entry speed
293 // thus, max exit will always be nominal
294 if (nominal_length_flag
)
295 return nominal_speed
;
297 // otherwise, we have to work out max exit speed based on entry and acceleration
298 float max
= max_allowable_speed(-this->acceleration
, this->entry_speed
, this->millimeters
);
300 return min(max
, nominal_speed
);
303 // prepare block for the step ticker, called everytime the block changes
304 // this is done during planning so does not delay tick generation and step ticker can simply grab the next block during the interrupt
305 void Block::prepare()
307 float inv
= 1.0F
/ this->steps_event_count
;
308 for (uint8_t m
= 0; m
< n_actuators
; m
++) {
309 uint32_t steps
= this->steps
[m
];
310 this->tick_info
[m
].steps_to_move
= steps
;
311 if(steps
== 0) continue;
313 float aratio
= inv
* steps
;
314 this->tick_info
[m
].steps_per_tick
= STEPTICKER_TOFP((this->initial_rate
* aratio
) / STEP_TICKER_FREQUENCY
); // steps/sec / tick frequency to get steps per tick in 2.62 fixed point
315 this->tick_info
[m
].counter
= 0; // 2.62 fixed point
316 this->tick_info
[m
].step_count
= 0;
317 this->tick_info
[m
].next_accel_event
= this->total_move_ticks
+ 1;
319 double acceleration_change
= 0;
320 if(this->accelerate_until
!= 0) { // If the next accel event is the end of accel
321 this->tick_info
[m
].next_accel_event
= this->accelerate_until
;
322 acceleration_change
= this->acceleration_per_tick
;
324 } else if(this->decelerate_after
== 0 /*&& this->accelerate_until == 0*/) {
325 // we start off decelerating
326 acceleration_change
= -this->deceleration_per_tick
;
328 } else if(this->decelerate_after
!= this->total_move_ticks
/*&& this->accelerate_until == 0*/) {
329 // If the next event is the start of decel ( don't set this if the next accel event is accel end )
330 this->tick_info
[m
].next_accel_event
= this->decelerate_after
;
333 // convert to fixed point after scaling
334 this->tick_info
[m
].acceleration_change
= STEPTICKER_TOFP(acceleration_change
* aratio
);
335 this->tick_info
[m
].deceleration_change
= -STEPTICKER_TOFP(this->deceleration_per_tick
* aratio
);
336 this->tick_info
[m
].plateau_rate
= STEPTICKER_TOFP((this->maximum_rate
* aratio
) / STEP_TICKER_FREQUENCY
);
339 THEKERNEL
->streams
->printf("spt: %08lX %08lX, ac: %08lX %08lX, dc: %08lX %08lX, pr: %08lX %08lX\n",
340 (uint32_t)(this->tick_info
[m
].steps_per_tick
>>32), // 2.62 fixed point
341 (uint32_t)(this->tick_info
[m
].steps_per_tick
&0xFFFFFFFF), // 2.62 fixed point
342 (uint32_t)(this->tick_info
[m
].acceleration_change
>>32), // 2.62 fixed point signed
343 (uint32_t)(this->tick_info
[m
].acceleration_change
&0xFFFFFFFF), // 2.62 fixed point signed
344 (uint32_t)(this->tick_info
[m
].deceleration_change
>>32), // 2.62 fixed point
345 (uint32_t)(this->tick_info
[m
].deceleration_change
&0xFFFFFFFF), // 2.62 fixed point
346 (uint32_t)(this->tick_info
[m
].plateau_rate
>>32), // 2.62 fixed point
347 (uint32_t)(this->tick_info
[m
].plateau_rate
&0xFFFFFFFF) // 2.62 fixed point
353 // returns current rate (steps/sec) for the given actuator
354 float Block::get_trapezoid_rate(int i
) const
356 // convert steps per tick from fixed point to float and convert to steps/sec
357 // FIXME steps_per_tick can change at any time, potential race condition if it changes while being read here
358 return STEPTICKER_FROMFP(tick_info
[i
].steps_per_tick
) * STEP_TICKER_FREQUENCY
;