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"
25 #define STEP_TICKER_FREQUENCY THEKERNEL->step_ticker->get_frequency()
26 #define STEP_TICKER_FREQUENCY_2 (STEP_TICKER_FREQUENCY*STEP_TICKER_FREQUENCY)
28 uint8_t Block::n_actuators
= 0;
30 // A block represents a movement, it's length for each stepper motor, and the corresponding acceleration curves.
31 // It's stacked on a queue, and that queue is then executed in order, to move the motors.
32 // Most of the accel math is also done in this class
33 // And GCode objects for use in on_gcode_execute are also help in here
46 steps_event_count
= 0;
52 acceleration
= 100.0F
; // we don't want to get divide by zeroes if this is not set
57 recalculate_flag
= false;
58 nominal_length_flag
= false;
59 max_entry_speed
= 0.0F
;
65 acceleration_per_tick
= 0;
66 deceleration_per_tick
= 0;
68 if(tick_info
.size() != n_actuators
) {
69 tick_info
.resize(n_actuators
);
71 for(auto &i
: tick_info
) {
74 i
.acceleration_change
= 0;
75 i
.deceleration_change
= 0;
79 i
.next_accel_event
= 0;
83 void Block::debug() const
85 THEKERNEL
->streams
->printf("%p: steps-X:%lu Y:%lu Z:%lu ", this, this->steps
[0], this->steps
[1], this->steps
[2]);
86 for (size_t i
= E_AXIS
; i
< n_actuators
; ++i
) {
87 THEKERNEL
->streams
->printf("%c:%lu ", 'A' + i
-E_AXIS
, this->steps
[i
]);
89 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",
90 this->steps_event_count
,
95 this->accelerate_until
,
96 this->decelerate_after
,
97 this->total_move_ticks
,
101 this->max_entry_speed
,
107 recalculate_flag
? 1 : 0,
108 nominal_length_flag
? 1 : 0,
109 total_move_ticks
/STEP_TICKER_FREQUENCY
114 /* Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
115 // The factors represent a factor of braking and must be in the range 0.0-1.0.
116 // +--------+ <- nominal_rate
118 // nominal_rate*entry_factor -> + \
119 // | + <- nominal_rate*exit_factor
123 void Block::calculate_trapezoid( float entryspeed
, float exitspeed
)
125 // if block is currently executing, don't touch anything!
126 if (is_ticking
) return;
128 float initial_rate
= this->nominal_rate
* (entryspeed
/ this->nominal_speed
); // steps/sec
129 float final_rate
= this->nominal_rate
* (exitspeed
/ this->nominal_speed
);
130 //printf("Initial rate: %f, final_rate: %f\n", initial_rate, final_rate);
131 // How many steps ( can be fractions of steps, we need very precise values ) to accelerate and decelerate
132 // This is a simplification to get rid of rate_delta and get the steps/s² accel directly from the mm/s² accel
133 float acceleration_per_second
= (this->acceleration
* this->steps_event_count
) / this->millimeters
;
135 float maximum_possible_rate
= sqrtf( ( this->steps_event_count
* acceleration_per_second
) + ( ( powf(initial_rate
, 2) + powf(final_rate
, 2) ) / 2.0F
) );
137 //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);
139 // Now this is the maximum rate we'll achieve this move, either because
140 // it's the higher we can achieve, or because it's the higher we are
141 // allowed to achieve
142 this->maximum_rate
= std::min(maximum_possible_rate
, this->nominal_rate
);
144 // Now figure out how long it takes to accelerate in seconds
145 float time_to_accelerate
= ( this->maximum_rate
- initial_rate
) / acceleration_per_second
;
147 // Now figure out how long it takes to decelerate
148 float time_to_decelerate
= ( final_rate
- this->maximum_rate
) / -acceleration_per_second
;
150 // Now we know how long it takes to accelerate and decelerate, but we must
151 // also know how long the entire move takes so we can figure out how long
152 // is the plateau if there is one
153 float plateau_time
= 0;
155 // Only if there is actually a plateau ( we are limited by nominal_rate )
156 if(maximum_possible_rate
> this->nominal_rate
) {
157 // Figure out the acceleration and deceleration distances ( in steps )
158 float acceleration_distance
= ( ( initial_rate
+ this->maximum_rate
) / 2.0F
) * time_to_accelerate
;
159 float deceleration_distance
= ( ( this->maximum_rate
+ final_rate
) / 2.0F
) * time_to_decelerate
;
161 // Figure out the plateau steps
162 float plateau_distance
= this->steps_event_count
- acceleration_distance
- deceleration_distance
;
164 // Figure out the plateau time in seconds
165 plateau_time
= plateau_distance
/ this->maximum_rate
;
168 // Figure out how long the move takes total ( in seconds )
169 float total_move_time
= time_to_accelerate
+ time_to_decelerate
+ plateau_time
;
170 //puts "total move time: #{total_move_time}s time to accelerate: #{time_to_accelerate}, time to decelerate: #{time_to_decelerate}"
172 // We now have the full timing for acceleration, plateau and deceleration,
173 // yay \o/ Now this is very important these are in seconds, and we need to
174 // round them into ticks. This means instead of accelerating in 100.23
175 // ticks we'll accelerate in 100 ticks. Which means to reach the exact
176 // speed we want to reach, we must figure out a new/slightly different
177 // acceleration/deceleration to be sure we accelerate and decelerate at
178 // the exact rate we want
180 // First off round total time, acceleration time and deceleration time in ticks
181 // NOTE we need to make sure this is no less than 1 which would happen if the time to accelerate was less than the current step period
182 uint32_t acceleration_ticks
= ceilf( time_to_accelerate
* STEP_TICKER_FREQUENCY
);
183 uint32_t deceleration_ticks
= ceilf( 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
= ( this->maximum_rate
- initial_rate
) / acceleration_time
;
194 float deceleration_in_steps
= ( this->maximum_rate
- final_rate
) / deceleration_time
;
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}, acceleration_per_tick: #{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
223 // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
224 // acceleration within the allotted distance.
225 float Block::max_allowable_speed(float acceleration
, float target_velocity
, float distance
)
227 return sqrtf(target_velocity
* target_velocity
- 2.0F
* acceleration
* distance
);
230 // Called by Planner::recalculate() when scanning the plan from last to first entry.
231 float Block::reverse_pass(float exit_speed
)
233 // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
234 // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
235 // check for maximum allowable speed reductions to ensure maximum possible planned speed.
236 if (this->entry_speed
!= this->max_entry_speed
) {
237 // If nominal length true, max junction speed is guaranteed to be reached. Only compute
238 // for max allowable speed if block is decelerating and nominal length is false.
239 if ((!this->nominal_length_flag
) && (this->max_entry_speed
> exit_speed
)) {
240 float max_entry_speed
= max_allowable_speed(-this->acceleration
, exit_speed
, this->millimeters
);
242 this->entry_speed
= min(max_entry_speed
, this->max_entry_speed
);
244 return this->entry_speed
;
246 this->entry_speed
= this->max_entry_speed
;
249 return this->entry_speed
;
253 // Called by Planner::recalculate() when scanning the plan from first to last entry.
254 // returns maximum exit speed of this block
255 float Block::forward_pass(float prev_max_exit_speed
)
257 // If the previous block is an acceleration block, but it is not long enough to complete the
258 // full speed change within the block, we need to adjust the entry speed accordingly. Entry
259 // speeds have already been reset, maximized, and reverse planned by reverse planner.
260 // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
262 // TODO: find out if both of these checks are necessary
263 if (prev_max_exit_speed
> nominal_speed
)
264 prev_max_exit_speed
= nominal_speed
;
265 if (prev_max_exit_speed
> max_entry_speed
)
266 prev_max_exit_speed
= max_entry_speed
;
268 if (prev_max_exit_speed
<= entry_speed
) {
270 entry_speed
= prev_max_exit_speed
;
271 // since we're now acceleration or cruise limited
272 // we don't need to recalculate our entry speed anymore
273 recalculate_flag
= false;
276 // // decel limited, do nothing
278 return max_exit_speed();
281 float Block::max_exit_speed()
283 // if block is currently executing, return cached exit speed from calculate_trapezoid
284 // this ensures that a block following a currently executing block will have correct entry speed
286 return this->exit_speed
;
288 // if nominal_length_flag is asserted
289 // we are guaranteed to reach nominal speed regardless of entry speed
290 // thus, max exit will always be nominal
291 if (nominal_length_flag
)
292 return nominal_speed
;
294 // otherwise, we have to work out max exit speed based on entry and acceleration
295 float max
= max_allowable_speed(-this->acceleration
, this->entry_speed
, this->millimeters
);
297 return min(max
, nominal_speed
);
300 // prepare block for the step ticker, called everytime the block changes
301 // this is done during planning so does not delay tick generation and step ticker can simply grab the next block during the interrupt
302 void Block::prepare()
304 float inv
= 1.0F
/ this->steps_event_count
;
305 for (uint8_t m
= 0; m
< n_actuators
; m
++) {
306 uint32_t steps
= this->steps
[m
];
307 this->tick_info
[m
].steps_to_move
= steps
;
308 if(steps
== 0) continue;
310 float aratio
= inv
* steps
;
311 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 2.30 fixed point
312 this->tick_info
[m
].counter
= 0; // 2.30 fixed point
313 this->tick_info
[m
].step_count
= 0;
314 this->tick_info
[m
].next_accel_event
= this->total_move_ticks
+ 1;
316 float acceleration_change
= 0;
317 if(this->accelerate_until
!= 0) { // If the next accel event is the end of accel
318 this->tick_info
[m
].next_accel_event
= this->accelerate_until
;
319 acceleration_change
= this->acceleration_per_tick
;
321 } else if(this->decelerate_after
== 0 /*&& this->accelerate_until == 0*/) {
322 // we start off decelerating
323 acceleration_change
= -this->deceleration_per_tick
;
325 } else if(this->decelerate_after
!= this->total_move_ticks
/*&& this->accelerate_until == 0*/) {
326 // If the next event is the start of decel ( don't set this if the next accel event is accel end )
327 this->tick_info
[m
].next_accel_event
= this->decelerate_after
;
330 // convert to fixed point after scaling
331 this->tick_info
[m
].acceleration_change
= STEPTICKER_TOFP(acceleration_change
* aratio
);
332 this->tick_info
[m
].deceleration_change
= -STEPTICKER_TOFP(this->deceleration_per_tick
* aratio
);
333 this->tick_info
[m
].plateau_rate
= STEPTICKER_TOFP((this->maximum_rate
* aratio
) / STEP_TICKER_FREQUENCY
);
337 // returns current rate (steps/sec) for the given actuator
338 float Block::get_trapezoid_rate(int i
) const
340 // convert steps per tick from fixed point to float and convert to steps/sec
341 // FIXME steps_per_tick can change at any time, potential race condition if it changes while being read here
342 return STEPTICKER_FROMFP(tick_info
[i
].steps_per_tick
) * STEP_TICKER_FREQUENCY
;