src/libs/StepperMotor.cpp

   1 /*
   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/>.
   6 */
   7 #include "StepperMotor.h"
   8
   9 #include "Kernel.h"
  10 #include "MRI_Hooks.h"
  11 #include "StepTicker.h"
  12
  13 #include <math.h>
  14
  15 // in steps/sec the default minimum speed (was 20steps/sec hardcoded)
  16 float StepperMotor::default_minimum_actuator_rate= 20.0F;
  17
  18 // A StepperMotor represents an actual stepper motor. It is used to generate steps that move the actual motor at a given speed
  19
  20 StepperMotor::StepperMotor()
  21 {
  22     init();
  23 }
  24
  25 StepperMotor::StepperMotor(Pin &step, Pin &dir, Pin &en) : step_pin(step), dir_pin(dir), en_pin(en)
  26 {
  27     init();
  28     enable(false);
  29     set_high_on_debug(en.port_number, en.pin);
  30 }
  31
  32 StepperMotor::~StepperMotor()
  33 {
  34 }
  35
  36 void StepperMotor::init()
  37 {
  38     // register this motor with the step ticker, and get its index in that array and bit position
  39     this->index= THEKERNEL->step_ticker->register_motor(this);
  40     this->moving = false;
  41     this->fx_counter = 0;
  42     this->fx_ticks_per_step = 0xFFFFF000UL; // some big number so we don't start stepping before it is set
  43     this->stepped = 0;
  44     this->steps_to_move = 0;
  45     this->is_move_finished = false;
  46     this->last_step_tick_valid= false;
  47     this->last_step_tick= 0;
  48     this->force_finish= false;
  49
  50     steps_per_mm         = 1.0F;
  51     max_rate             = 50.0F;
  52     minimum_step_rate    = default_minimum_actuator_rate;
  53
  54     last_milestone_steps = 0;
  55     last_milestone_mm    = 0.0F;
  56     current_position_steps= 0;
  57     signal_step= 0;
  58 }
  59
  60
  61 // This is called ( see the .h file, we had to put a part of things there for obscure inline reasons ) when a step has to be generated
  62 // we also here check if the move is finished etc ..
  63 // This is in highest priority interrupt so cannot be pre-empted
  64 void StepperMotor::step()
  65 {
  66     // ignore if we are still processing the end of a block
  67     if(this->is_move_finished) return;
  68
  69     if(!this->force_finish) {
  70         // output to pins 37t
  71         this->step_pin.set( 1 );
  72
  73         // move counter back 11t
  74         this->fx_counter -= this->fx_ticks_per_step;
  75
  76         // we have moved a step 9t
  77         this->stepped++;
  78
  79         // keep track of actuators actual position in steps
  80         this->current_position_steps += (this->direction ? -1 : 1);
  81
  82         // we may need to callback on a specific step, usually used to synchronize deceleration timer
  83         if(this->signal_step != 0 && this->stepped == this->signal_step) {
  84             THEKERNEL->step_ticker->synchronize_acceleration(true);
  85             this->signal_step= 0;
  86         }
  87     }
  88
  89     // Is this move finished ?
  90     if( this->force_finish || this->stepped == this->steps_to_move) {
  91         // Mark it as finished, then StepTicker will call signal_move_finished()
  92         // This is so we don't call that before all the steps have been generated for this tick()
  93         this->is_move_finished = true;
  94         THEKERNEL->step_ticker->a_move_finished= true;
  95         this->last_step_tick= THEKERNEL->step_ticker->get_tick_cnt(); // remember when last step was
  96         if(this->force_finish) this->steps_to_move = stepped;
  97     }
  98 }
  99
 100 // If the move is finished, the StepTicker will call this ( because we asked it to in tick() )
 101 void StepperMotor::signal_move_finished()
 102 {
 103     // work is done ! 8t
 104     this->moving = false;
 105     this->steps_to_move = 0;
 106     this->minimum_step_rate = default_minimum_actuator_rate;
 107
 108     // signal it to whatever cares
 109     // in this call a new block may start, new moves set and new speeds
 110     this->end_hook->call();
 111
 112     // We only need to do this if we were not instructed to move
 113     if( !this->moving ) {
 114         this->update_exit_tick();
 115     }
 116
 117     this->is_move_finished = false;
 118 }
 119
 120 // This is just a way not to check for ( !this->moving || this->fx_ticks_per_step == 0 ) at every tick()
 121 void StepperMotor::update_exit_tick()
 122 {
 123     if( !this->moving || this->steps_to_move == 0 ) {
 124         // No more ticks will be recieved and no more events from StepTicker
 125         THEKERNEL->step_ticker->remove_motor_from_active_list(this);
 126     } else {
 127         // we will now get ticks and StepTIcker will send us events
 128         THEKERNEL->step_ticker->add_motor_to_active_list(this);
 129     }
 130 }
 131
 132 // Instruct the StepperMotor to move a certain number of steps
 133 StepperMotor* StepperMotor::move( bool direction, unsigned int steps, float initial_speed)
 134 {
 135     this->dir_pin.set(direction);
 136     this->direction = direction;
 137     this->force_finish= false;
 138
 139     // How many steps we have to move until the move is done
 140     this->steps_to_move = steps;
 141
 142     // Zero our tool counters
 143     this->stepped = 0;
 144     this->fx_ticks_per_step = 0xFFFFF000UL; // some big number so we don't start stepping before it is set again
 145     if(this->last_step_tick_valid) {
 146         // we set this based on when the last step was, thus compensating for missed ticks
 147         uint32_t ts= THEKERNEL->step_ticker->ticks_since(this->last_step_tick);
 148         // if an axis stops too soon then we can get a huge number of ticks here which causes problems, so if the number of ticks is too great we ignore them
 149         // example of when this happens is when one axis is going very slow an the min 20steps/sec kicks in, the axis will reach its target much sooner leaving a long gap
 150         // until the end of the block.
 151         // TODO we may need to set this based on the current step rate, trouble is we don't know what that is yet, we could use the last fx_ticks_per_step as a guide
 152         if(ts > 5) ts= 5; // limit to 50us catch up around 1-2 steps
 153         else if(ts > 15) ts= 0; // no way to know what the delay was
 154         this->fx_counter= ts*fx_increment;
 155     }else{
 156         this->fx_counter = 0; // set to zero as there was no step last block
 157     }
 158
 159     // Starting now we are moving
 160     if( steps > 0 ) {
 161         if(initial_speed >= 0.0F) set_speed(initial_speed);
 162         this->moving = true;
 163     } else {
 164         this->moving = false;
 165     }
 166     this->update_exit_tick();
 167     return this;
 168 }
 169
 170 // Set the speed at which this stepper moves in steps/sec, should be called set_step_rate()
 171 // we need to make sure that we have a minimum speed here and that it fits the 32bit fixed point fx counters
 172 // Note nothing will really ever go as slow as the minimum speed here, it is just forced to avoid bad errors
 173 // fx_ticks_per_step is what actually sets the step rate, it is fixed point 18.14
 174 StepperMotor* StepperMotor::set_speed( float speed )
 175 {
 176     if(speed < minimum_step_rate) {
 177         speed= minimum_step_rate;
 178     }
 179
 180     // if(speed <= 0.0F) { // we can't actually do 0 but we can get close, need to avoid divide by zero later on
 181     //     this->fx_ticks_per_step= 0xFFFFFFFFUL; // 0.381 steps/sec
 182     //     this->steps_per_second = THEKERNEL->step_ticker->get_frequency() / (this->fx_ticks_per_step >> fx_shift);
 183     //     return;
 184     // }
 185
 186     // How many steps we must output per second
 187     this->steps_per_second = speed;
 188
 189     // set the new speed, NOTE this can be pre-empted by stepticker so the following write needs to be atomic
 190     this->fx_ticks_per_step= floor(fx_increment * THEKERNEL->step_ticker->get_frequency() / speed);
 191     return this;
 192 }
 193
 194 void StepperMotor::change_steps_per_mm(float new_steps)
 195 {
 196     steps_per_mm = new_steps;
 197     last_milestone_steps = lroundf(last_milestone_mm * steps_per_mm);
 198     current_position_steps = last_milestone_steps;
 199 }
 200
 201 void StepperMotor::change_last_milestone(float new_milestone)
 202 {
 203     last_milestone_mm = new_milestone;
 204     last_milestone_steps = lroundf(last_milestone_mm * steps_per_mm);
 205     current_position_steps = last_milestone_steps;
 206 }
 207
 208 int  StepperMotor::steps_to_target(float target)
 209 {
 210     int target_steps = lroundf(target * steps_per_mm);
 211     return target_steps - last_milestone_steps;
 212 }