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
  49     steps_per_mm         = 1.0F;
  50     max_rate             = 50.0F;
  51     minimum_step_rate    = default_minimum_actuator_rate;
  52
  53     last_milestone_steps = 0;
  54     last_milestone_mm    = 0.0F;
  55     current_position_steps= 0;
  56     signal_step= 0;
  57 }
  58
  59
  60 // 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
  61 // we also here check if the move is finished etc ..
  62 // This is in highest priority interrupt so cannot be pre-empted
  63 void StepperMotor::step()
  64 {
  65     // ignore if we are still processing the end of a block
  66     if(this->is_move_finished) return;
  67
  68     // output to pins 37t
  69     this->step_pin.set( 1 );
  70
  71     // move counter back 11t
  72     this->fx_counter -= this->fx_ticks_per_step;
  73
  74     // we have moved a step 9t
  75     this->stepped++;
  76
  77     // keep track of actuators actual position in steps
  78     this->current_position_steps += (this->direction ? -1 : 1);
  79
  80     // we may need to callback on a specific step, usually used to synchronize deceleration timer
  81     if(this->signal_step != 0 && this->stepped == this->signal_step) {
  82         THEKERNEL->step_ticker->synchronize_acceleration(true);
  83         this->signal_step= 0;
  84     }
  85
  86     // Is this move finished ?
  87     if( this->stepped == this->steps_to_move ) {
  88         // Mark it as finished, then StepTicker will call signal_mode_finished()
  89         // This is so we don't call that before all the steps have been generated for this tick()
  90         this->is_move_finished = true;
  91         THEKERNEL->step_ticker->a_move_finished= true;
  92         this->last_step_tick= THEKERNEL->step_ticker->get_tick_cnt(); // remember when last step was
  93     }
  94 }
  95
  96
  97 // If the move is finished, the StepTicker will call this ( because we asked it to in tick() )
  98 void StepperMotor::signal_move_finished()
  99 {
 100     // work is done ! 8t
 101     this->moving = false;
 102     this->steps_to_move = 0;
 103     this->minimum_step_rate = default_minimum_actuator_rate;
 104
 105     // signal it to whatever cares
 106     // in this call a new block may start, new moves set and new speeds
 107     this->end_hook->call();
 108
 109     // We only need to do this if we were not instructed to move
 110     if( !this->moving ) {
 111         this->update_exit_tick();
 112     }
 113
 114     this->is_move_finished = false;
 115 }
 116
 117 // This is just a way not to check for ( !this->moving || this->fx_ticks_per_step == 0 ) at every tick()
 118 void StepperMotor::update_exit_tick()
 119 {
 120     if( !this->moving || this->steps_to_move == 0 ) {
 121         // No more ticks will be recieved and no more events from StepTicker
 122         THEKERNEL->step_ticker->remove_motor_from_active_list(this);
 123     } else {
 124         // we will now get ticks and StepTIcker will send us events
 125         THEKERNEL->step_ticker->add_motor_to_active_list(this);
 126     }
 127 }
 128
 129 // Instruct the StepperMotor to move a certain number of steps
 130 StepperMotor* StepperMotor::move( bool direction, unsigned int steps, float initial_speed)
 131 {
 132     this->dir_pin.set(direction);
 133     this->direction = direction;
 134
 135     // How many steps we have to move until the move is done
 136     this->steps_to_move = steps;
 137
 138     // Zero our tool counters
 139     this->stepped = 0;
 140     this->fx_ticks_per_step = 0xFFFFF000UL; // some big number so we don't start stepping before it is set again
 141     if(this->last_step_tick_valid) {
 142         // we set this based on when the last step was, thus compensating for missed ticks
 143         uint32_t ts= THEKERNEL->step_ticker->ticks_since(this->last_step_tick);
 144         // 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
 145         // 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
 146         // until the end of the block.
 147         // 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
 148         if(ts > 5) ts= 5; // limit to 50us catch up around 1-2 steps
 149         else if(ts > 15) ts= 0; // no way to know what the delay was
 150         this->fx_counter= ts*fx_increment;
 151     }else{
 152         this->fx_counter = 0; // set to zero as there was no step last block
 153     }
 154
 155     // Starting now we are moving
 156     if( steps > 0 ) {
 157         if(initial_speed >= 0.0F) set_speed(initial_speed);
 158         this->moving = true;
 159     } else {
 160         this->moving = false;
 161     }
 162     this->update_exit_tick();
 163     return this;
 164 }
 165
 166 // Set the speed at which this stepper moves in steps/sec, should be called set_step_rate()
 167 // we need to make sure that we have a minimum speed here and that it fits the 32bit fixed point fx counters
 168 // Note nothing will really ever go as slow as the minimum speed here, it is just forced to avoid bad errors
 169 // fx_ticks_per_step is what actually sets the step rate, it is fixed point 18.14
 170 StepperMotor* StepperMotor::set_speed( float speed )
 171 {
 172     if(speed < minimum_step_rate) {
 173         speed= minimum_step_rate;
 174     }
 175
 176     // if(speed <= 0.0F) { // we can't actually do 0 but we can get close, need to avoid divide by zero later on
 177     //     this->fx_ticks_per_step= 0xFFFFFFFFUL; // 0.381 steps/sec
 178     //     this->steps_per_second = THEKERNEL->step_ticker->get_frequency() / (this->fx_ticks_per_step >> fx_shift);
 179     //     return;
 180     // }
 181
 182     // How many steps we must output per second
 183     this->steps_per_second = speed;
 184
 185     // set the new speed, NOTE this can be pre-empted by stepticker so the following write needs to be atomic
 186     this->fx_ticks_per_step= floor(fx_increment * THEKERNEL->step_ticker->get_frequency() / speed);
 187     return this;
 188 }
 189
 190 void StepperMotor::change_steps_per_mm(float new_steps)
 191 {
 192     steps_per_mm = new_steps;
 193     last_milestone_steps = lround(last_milestone_mm * steps_per_mm);
 194     current_position_steps = last_milestone_steps;
 195 }
 196
 197 void StepperMotor::change_last_milestone(float new_milestone)
 198 {
 199     last_milestone_mm = new_milestone;
 200     last_milestone_steps = lround(last_milestone_mm * steps_per_mm);
 201     current_position_steps = last_milestone_steps;
 202 }
 203
 204 int  StepperMotor::steps_to_target(float target)
 205 {
 206     int target_steps = lround(target * steps_per_mm);
 207     return target_steps - last_milestone_steps;
 208 }