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"
19 #include "platform_memory.h"
27 #define STEP_TICKER_FREQUENCY THEKERNEL->step_ticker->get_frequency()
29 uint8_t Block::n_actuators
= 0;
30 double Block::fp_scale
= 0;
32 // A block represents a movement, it's length for each stepper motor, and the corresponding acceleration curves.
33 // It's stacked on a queue, and that queue is then executed in order, to move the motors.
34 // Most of the accel math is also done in this class
35 // And GCode objects for use in on_gcode_execute are also help in here
43 void Block::init(uint8_t n
)
46 fp_scale
= (double)STEPTICKER_FPSCALE
/ pow((double)STEP_TICKER_FREQUENCY
, 2.0); // we scale up by fixed point offset first to avoid tiny values
55 steps_event_count
= 0;
61 acceleration
= 100.0F
; // we don't want to get divide by zeroes if this is not set
66 recalculate_flag
= false;
67 nominal_length_flag
= false;
68 max_entry_speed
= 0.0F
;
75 if(tick_info
== nullptr) {
76 // we create this once for this block in AHB0 to save memory
77 tick_info
= (tickinfo_t
*)AHB0
.alloc(sizeof(tickinfo_t
) * n_actuators
);
80 for(int i
= 0; i
< n_actuators
; ++i
) {
81 tick_info
[i
].steps_per_tick
= 0;
82 tick_info
[i
].counter
= 0;
83 tick_info
[i
].acceleration_change
= 0;
84 tick_info
[i
].deceleration_change
= 0;
85 tick_info
[i
].plateau_rate
= 0;
86 tick_info
[i
].steps_to_move
= 0;
87 tick_info
[i
].step_count
= 0;
88 tick_info
[i
].next_accel_event
= 0;
92 void Block::debug() const
94 THEKERNEL
->streams
->printf("%p: steps-X:%lu Y:%lu Z:%lu ", this, this->steps
[0], this->steps
[1], this->steps
[2]);
95 for (size_t i
= E_AXIS
; i
< n_actuators
; ++i
) {
96 THEKERNEL
->streams
->printf("%c:%lu ", 'A' + i
-E_AXIS
, this->steps
[i
]);
98 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",
99 this->steps_event_count
,
104 this->accelerate_until
,
105 this->decelerate_after
,
106 this->total_move_ticks
,
110 this->max_entry_speed
,
116 recalculate_flag
? 1 : 0,
117 nominal_length_flag
? 1 : 0,
118 total_move_ticks
/STEP_TICKER_FREQUENCY
123 /* Calculates trapezoid parameters so that the entry- and exit-speed is compensated by the provided factors.
124 // The factors represent a factor of braking and must be in the range 0.0-1.0.
125 // +--------+ <- nominal_rate
127 // nominal_rate*entry_factor -> + \
128 // | + <- nominal_rate*exit_factor
132 void Block::calculate_trapezoid( float entryspeed
, float exitspeed
)
134 // if block is currently executing, don't touch anything!
135 if (is_ticking
) return;
137 float initial_rate
= this->nominal_rate
* (entryspeed
/ this->nominal_speed
); // steps/sec
138 float final_rate
= this->nominal_rate
* (exitspeed
/ this->nominal_speed
);
139 //printf("Initial rate: %f, final_rate: %f\n", initial_rate, final_rate);
140 // How many steps ( can be fractions of steps, we need very precise values ) to accelerate and decelerate
141 // This is a simplification to get rid of rate_delta and get the steps/s² accel directly from the mm/s² accel
142 float acceleration_per_second
= (this->acceleration
* this->steps_event_count
) / this->millimeters
;
144 float maximum_possible_rate
= sqrtf( ( this->steps_event_count
* acceleration_per_second
) + ( ( powf(initial_rate
, 2) + powf(final_rate
, 2) ) / 2.0F
) );
146 //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);
148 // Now this is the maximum rate we'll achieve this move, either because
149 // it's the higher we can achieve, or because it's the higher we are
150 // allowed to achieve
151 this->maximum_rate
= std::min(maximum_possible_rate
, this->nominal_rate
);
153 // Now figure out how long it takes to accelerate in seconds
154 float time_to_accelerate
= ( this->maximum_rate
- initial_rate
) / acceleration_per_second
;
156 // Now figure out how long it takes to decelerate
157 float time_to_decelerate
= ( final_rate
- this->maximum_rate
) / -acceleration_per_second
;
159 // Now we know how long it takes to accelerate and decelerate, but we must
160 // also know how long the entire move takes so we can figure out how long
161 // is the plateau if there is one
162 float plateau_time
= 0;
164 // Only if there is actually a plateau ( we are limited by nominal_rate )
165 if(maximum_possible_rate
> this->nominal_rate
) {
166 // Figure out the acceleration and deceleration distances ( in steps )
167 float acceleration_distance
= ( ( initial_rate
+ this->maximum_rate
) / 2.0F
) * time_to_accelerate
;
168 float deceleration_distance
= ( ( this->maximum_rate
+ final_rate
) / 2.0F
) * time_to_decelerate
;
170 // Figure out the plateau steps
171 float plateau_distance
= this->steps_event_count
- acceleration_distance
- deceleration_distance
;
173 // Figure out the plateau time in seconds
174 plateau_time
= plateau_distance
/ this->maximum_rate
;
177 // Figure out how long the move takes total ( in seconds )
178 float total_move_time
= time_to_accelerate
+ time_to_decelerate
+ plateau_time
;
179 //puts "total move time: #{total_move_time}s time to accelerate: #{time_to_accelerate}, time to decelerate: #{time_to_decelerate}"
181 // We now have the full timing for acceleration, plateau and deceleration,
182 // yay \o/ Now this is very important these are in seconds, and we need to
183 // round them into ticks. This means instead of accelerating in 100.23
184 // ticks we'll accelerate in 100 ticks. Which means to reach the exact
185 // speed we want to reach, we must figure out a new/slightly different
186 // acceleration/deceleration to be sure we accelerate and decelerate at
187 // the exact rate we want
189 // First off round total time, acceleration time and deceleration time in ticks
190 uint32_t acceleration_ticks
= floorf( time_to_accelerate
* STEP_TICKER_FREQUENCY
);
191 uint32_t deceleration_ticks
= floorf( time_to_decelerate
* STEP_TICKER_FREQUENCY
);
192 uint32_t total_move_ticks
= floorf( total_move_time
* STEP_TICKER_FREQUENCY
);
194 // Now deduce the plateau time for those new values expressed in tick
195 //uint32_t plateau_ticks = total_move_ticks - acceleration_ticks - deceleration_ticks;
197 // Now we figure out the acceleration value to reach EXACTLY maximum_rate(steps/s) in EXACTLY acceleration_ticks(ticks) amount of time in seconds
198 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
199 float deceleration_time
= deceleration_ticks
/ STEP_TICKER_FREQUENCY
;
201 float acceleration_in_steps
= (acceleration_time
> 0.0F
) ? ( this->maximum_rate
- initial_rate
) / acceleration_time
: 0;
202 float deceleration_in_steps
= (deceleration_time
> 0.0F
) ? ( this->maximum_rate
- final_rate
) / deceleration_time
: 0;
204 // we have a potential race condition here as we could get interrupted anywhere in the middle of this call, we need to lock
205 // the updates to the blocks to get around it
207 // Now figure out the two acceleration ramp change events in ticks
208 this->accelerate_until
= acceleration_ticks
;
209 this->decelerate_after
= total_move_ticks
- deceleration_ticks
;
211 // We now have everything we need for this block to call a Steppermotor->move method !!!!
212 // Theorically, if accel is done per tick, the speed curve should be perfect.
213 this->total_move_ticks
= total_move_ticks
;
215 this->initial_rate
= initial_rate
;
216 this->exit_speed
= exitspeed
;
218 // prepare the block for stepticker
219 this->prepare(acceleration_in_steps
, deceleration_in_steps
);
224 // Calculates the maximum allowable speed at this point when you must be able to reach target_velocity using the
225 // acceleration within the allotted distance.
226 float Block::max_allowable_speed(float acceleration
, float target_velocity
, float distance
)
228 return sqrtf(target_velocity
* target_velocity
- 2.0F
* acceleration
* distance
);
231 // Called by Planner::recalculate() when scanning the plan from last to first entry.
232 float Block::reverse_pass(float exit_speed
)
234 // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
235 // If not, block in state of acceleration or deceleration. Reset entry speed to maximum and
236 // check for maximum allowable speed reductions to ensure maximum possible planned speed.
237 if (this->entry_speed
!= this->max_entry_speed
) {
238 // If nominal length true, max junction speed is guaranteed to be reached. Only compute
239 // for max allowable speed if block is decelerating and nominal length is false.
240 if ((!this->nominal_length_flag
) && (this->max_entry_speed
> exit_speed
)) {
241 float max_entry_speed
= max_allowable_speed(-this->acceleration
, exit_speed
, this->millimeters
);
243 this->entry_speed
= min(max_entry_speed
, this->max_entry_speed
);
245 return this->entry_speed
;
247 this->entry_speed
= this->max_entry_speed
;
250 return this->entry_speed
;
254 // Called by Planner::recalculate() when scanning the plan from first to last entry.
255 // returns maximum exit speed of this block
256 float Block::forward_pass(float prev_max_exit_speed
)
258 // If the previous block is an acceleration block, but it is not long enough to complete the
259 // full speed change within the block, we need to adjust the entry speed accordingly. Entry
260 // speeds have already been reset, maximized, and reverse planned by reverse planner.
261 // If nominal length is true, max junction speed is guaranteed to be reached. No need to recheck.
263 // TODO: find out if both of these checks are necessary
264 if (prev_max_exit_speed
> nominal_speed
)
265 prev_max_exit_speed
= nominal_speed
;
266 if (prev_max_exit_speed
> max_entry_speed
)
267 prev_max_exit_speed
= max_entry_speed
;
269 if (prev_max_exit_speed
<= entry_speed
) {
271 entry_speed
= prev_max_exit_speed
;
272 // since we're now acceleration or cruise limited
273 // we don't need to recalculate our entry speed anymore
274 recalculate_flag
= false;
277 // // decel limited, do nothing
279 return max_exit_speed();
282 float Block::max_exit_speed()
284 // if block is currently executing, return cached exit speed from calculate_trapezoid
285 // this ensures that a block following a currently executing block will have correct entry speed
287 return this->exit_speed
;
289 // if nominal_length_flag is asserted
290 // we are guaranteed to reach nominal speed regardless of entry speed
291 // thus, max exit will always be nominal
292 if (nominal_length_flag
)
293 return nominal_speed
;
295 // otherwise, we have to work out max exit speed based on entry and acceleration
296 float max
= max_allowable_speed(-this->acceleration
, this->entry_speed
, this->millimeters
);
298 return min(max
, nominal_speed
);
301 // prepare block for the step ticker, called everytime the block changes
302 // this is done during planning so does not delay tick generation and step ticker can simply grab the next block during the interrupt
303 void Block::prepare(float acceleration_in_steps
, float deceleration_in_steps
)
306 float inv
= 1.0F
/ this->steps_event_count
;
308 // Now figure out the acceleration PER TICK, this should ideally be held as a double as it's very critical to the block timing
311 // float acceleration_per_tick = acceleration_in_steps / STEP_TICKER_FREQUENCY_2; // that is 100,000² too big for a float
312 // float deceleration_per_tick = deceleration_in_steps / STEP_TICKER_FREQUENCY_2;
313 double acceleration_per_tick
= acceleration_in_steps
* fp_scale
; // this is now scaled to fit a 2.30 fixed point number
314 double deceleration_per_tick
= deceleration_in_steps
* fp_scale
;
316 for (uint8_t m
= 0; m
< n_actuators
; m
++) {
317 uint32_t steps
= this->steps
[m
];
318 this->tick_info
[m
].steps_to_move
= steps
;
319 if(steps
== 0) continue;
321 float aratio
= inv
* steps
;
323 this->tick_info
[m
].steps_per_tick
= (int64_t)round((((double)this->initial_rate
* aratio
) / STEP_TICKER_FREQUENCY
) * STEPTICKER_FPSCALE
); // steps/sec / tick frequency to get steps per tick in 2.62 fixed point
324 this->tick_info
[m
].counter
= 0; // 2.62 fixed point
325 this->tick_info
[m
].step_count
= 0;
326 this->tick_info
[m
].next_accel_event
= this->total_move_ticks
+ 1;
328 double acceleration_change
= 0;
329 if(this->accelerate_until
!= 0) { // If the next accel event is the end of accel
330 this->tick_info
[m
].next_accel_event
= this->accelerate_until
;
331 acceleration_change
= acceleration_per_tick
;
333 } else if(this->decelerate_after
== 0 /*&& this->accelerate_until == 0*/) {
334 // we start off decelerating
335 acceleration_change
= -deceleration_per_tick
;
337 } else if(this->decelerate_after
!= this->total_move_ticks
/*&& this->accelerate_until == 0*/) {
338 // If the next event is the start of decel ( don't set this if the next accel event is accel end )
339 this->tick_info
[m
].next_accel_event
= this->decelerate_after
;
342 // already converted to fixed point just needs scaling by ratio
343 //#define STEPTICKER_TOFP(x) ((int64_t)round((double)(x)*STEPTICKER_FPSCALE))
344 this->tick_info
[m
].acceleration_change
= (int64_t)round(acceleration_change
* aratio
);
345 this->tick_info
[m
].deceleration_change
= -(int64_t)round(deceleration_per_tick
* aratio
);
346 this->tick_info
[m
].plateau_rate
= (int64_t)round(((this->maximum_rate
* aratio
) / STEP_TICKER_FREQUENCY
) * STEPTICKER_FPSCALE
);
349 THEKERNEL
->streams
->printf("spt: %08lX %08lX, ac: %08lX %08lX, dc: %08lX %08lX, pr: %08lX %08lX\n",
350 (uint32_t)(this->tick_info
[m
].steps_per_tick
>>32), // 2.62 fixed point
351 (uint32_t)(this->tick_info
[m
].steps_per_tick
&0xFFFFFFFF), // 2.62 fixed point
352 (uint32_t)(this->tick_info
[m
].acceleration_change
>>32), // 2.62 fixed point signed
353 (uint32_t)(this->tick_info
[m
].acceleration_change
&0xFFFFFFFF), // 2.62 fixed point signed
354 (uint32_t)(this->tick_info
[m
].deceleration_change
>>32), // 2.62 fixed point
355 (uint32_t)(this->tick_info
[m
].deceleration_change
&0xFFFFFFFF), // 2.62 fixed point
356 (uint32_t)(this->tick_info
[m
].plateau_rate
>>32), // 2.62 fixed point
357 (uint32_t)(this->tick_info
[m
].plateau_rate
&0xFFFFFFFF) // 2.62 fixed point
363 // returns current rate (steps/sec) for the given actuator
364 float Block::get_trapezoid_rate(int i
) const
366 // convert steps per tick from fixed point to float and convert to steps/sec
367 // FIXME steps_per_tick can change at any time, potential race condition if it changes while being read here
368 return STEPTICKER_FROMFP(tick_info
[i
].steps_per_tick
) * STEP_TICKER_FREQUENCY
;