Grbl代码分析 Planner_recalculate()

static void planner_recalculate()

{

  //读前一个块数据

  uint8_t block_index = plan_prev_block_index(block_buffer_head);

  // 如果前一个块已经优化了返回

  if (block_index == block_buffer_planned) { return; }

  /*粗略地最大化所有可能的加速曲线，从缓冲区的最后一个区块开始反向规划。当达到最后一个最优计划或尾部指针时，停止计划。注意：正向通道以后将完善和修正反向通道，以创建一个最佳计划。*/ 

 float entry_speed_sqr;

  plan_block_t *next;

  plan_block_t *current = &block_buffer[block_index];

  /*认为块最后的退出速度为0，按照块的加速度和移动距离计算出最大速度，这个速度和这块的进入速度比较，取最小值*/

  current->entry_speed_sqr = min( current->max_entry_speed_sqr, 2*current->acceleration*current->millimeters);

/*读取前一个块数据。后面的循环程序是从后往前计算每个块的进入速度，即计算块是不

是减速，如果是减速（小于max_entry_speed_sqr)，设置进入速度= entry_speed_sqr，如果大于max_entry_speed_sqr，表示这一段不是全程减速*/

  block_index = plan_prev_block_index(block_index);

  if (block_index == block_buffer_planned) { //如果这个块已经优化了

// 如果这个块是block_buffer_tail，更新step buffer

if (block_index == block_buffer_tail) { st_update_plan_block_parameters(); }

  } else {

    while (block_index != block_buffer_planned) {//只要没有优化，循环计算速度

      next = current;

      current = &block_buffer[block_index];

      block_index = plan_prev_block_index(block_index);

      // 如果这个块是block_buffer_tail，更新step buffer

      if (block_index == block_buffer_tail) { st_update_plan_block_parameters(); }

speed.

      if (current->entry_speed_sqr != current->max_entry_speed_sqr) {

        entry_speed_sqr = next->entry_speed_sqr + 2*current->acceleration*current->millimeters;

        if (entry_speed_sqr < current->max_entry_speed_sqr) {

          current->entry_speed_sqr = entry_speed_sqr;

        } else {

          current->entry_speed_sqr = current->max_entry_speed_sqr;

        }

      }

    }

  }

  /*向前推算优化速度。从几经优化的块出发，按照加速过程计算，如果推算的进入速度小于next->entry_speed_sqr，设置进入速度= entry_speed_sqr。置优化*/

.  next = &block_buffer[block_buffer_planned]; // Begin at buffer planned pointer

  block_index = plan_next_block_index(block_buffer_planned);

  while (block_index != block_buffer_head) {

    current = next;

    next = &block_buffer[block_index];

    if (current->entry_speed_sqr < next->entry_speed_sqr) {

      entry_speed_sqr = current->entry_speed_sqr + 2*current->acceleration*current->millimeters;

      if (entry_speed_sqr < next->entry_speed_sqr) {

        next->entry_speed_sqr = entry_speed_sqr;

        block_buffer_planned = block_index;

      }

}

//如果进入速度已经是max_entry_speed_sqr，没有优化的空间了，置优化标志

if (next->entry_speed_sqr == next->max_entry_speed_sqr) { block_buffer_planned = block_index; }

    block_index = plan_next_block_index( block_index );

  }

}