src/modules/robot/arm_solutions/RotatableDeltaSolution.cpp

   1 #include "RotatableDeltaSolution.h"
   2 #include "checksumm.h"
   3 #include "ConfigValue.h"
   4 #include "ConfigCache.h"
   5 #include "libs/Kernel.h"
   6 #include "libs/nuts_bolts.h"
   7 #include "libs/Config.h"
   8 #include "libs/utils.h"
   9 #include "StreamOutputPool.h"
  10 #include <fastmath.h>
  11
  12 #define delta_e_checksum                        CHECKSUM("delta_e_checksum")
  13 #define delta_f_checksum                        CHECKSUM("delta_f_checksum")
  14 #define delta_re_checksum                       CHECKSUM("delta_re_checksum")
  15 #define delta_rf_checksum                       CHECKSUM("delta_rf_checksum")
  16 #define delta_z_offset_checksum                 CHECKSUM("delta_z_offset_checksum")
  17
  18 #define delta_ee_offs_checksum                  CHECKSUM("delta_ee_offs_checksum")
  19 #define tool_offset_checksum                    CHECKSUM("tool_offset_checksum")
  20
  21 #ifndef alpha_steps_per_mm_checksum
  22   #define alpha_steps_per_mm_checksum           CHECKSUM("alpha_steps_per_mm_checksum");
  23 #endif
  24
  25 #ifndef beta_steps_per_mm_checksum
  26   #define beta_steps_per_mm_checksum            CHECKSUM("beta_steps_per_mm_checksum");
  27 #endif
  28
  29 #ifndef gamma_steps_per_mm_checksum
  30   #define gamma_steps_per_mm_checksum           CHECKSUM("gamma_steps_per_mm_checksum");
  31 #endif
  32
  33 const static float pi     = 3.14159265358979323846;    // PI
  34 const static float two_pi = 2 * pi;
  35 const static float sin120 = 0.86602540378443864676372317075294; //sqrt3/2.0
  36 const static float cos120 = -0.5;
  37 const static float tan60  = 1.7320508075688772935274463415059; //sqrt3;
  38 const static float sin30  = 0.5;
  39 const static float tan30  = 0.57735026918962576450914878050196; //1/sqrt3
  40
  41 RotatableDeltaSolution::RotatableDeltaSolution(Config* config)
  42 {
  43         // End effector length
  44         delta_e = config->value(delta_e_checksum)->by_default(131.636F)->as_number();
  45
  46         // Base length
  47         delta_f = config->value(delta_f_checksum)->by_default(190.526F)->as_number();
  48
  49         // Carbon rod length
  50         delta_re = config->value(delta_re_checksum)->by_default(270.000F)->as_number();
  51
  52         // Servo horn length
  53         delta_rf = config->value(delta_rf_checksum)->by_default(90.000F)->as_number();
  54
  55         // Distance from delta 8mm rod/pulley to table/bed,
  56         // NOTE: For OpenPnP, set the zero to be about 25mm above the bed..
  57         delta_z_offset = config->value(delta_z_offset_checksum)->by_default(290.700F)->as_number();
  58
  59         // Ball joint plane to bottom of end effector surface
  60         delta_ee_offs = config->value(delta_ee_offs_checksum)->by_default(15.000F)->as_number();
  61
  62         // Distance between end effector ball joint plane and tip of tool (PnP)
  63         tool_offset = config->value(tool_offset_checksum)->by_default(30.500F)->as_number();
  64
  65         init();
  66 }
  67
  68 // inverse kinematics
  69 // helper functions, calculates angle theta1 (for YZ-pane)
  70 int RotatableDeltaSolution::delta_calcAngleYZ(float x0, float y0, float z0, float &theta)
  71 {
  72     float y1 = -0.5F * tan30 * delta_f; // f/2 * tan 30
  73     y0      -=  0.5F * tan30 * delta_e; // shift center to edge
  74     // z = a + b*y
  75     float a = (x0*x0 + y0*y0 + z0*z0 + delta_rf*delta_rf - delta_re*delta_re - y1*y1) / (2.0F*z0);
  76     float b = (y1-y0)/z0;
  77
  78     float d = -(a+b*y1)*(a+b*y1) + delta_rf*(b*b*delta_rf+delta_rf); // discriminant
  79     if (d < 0.0F) return -1;                                            // non-existing point
  80
  81     float yj = (y1 - a*b - sqrtf(d))/(b*b + 1.0F);                     // choosing outer point
  82     float zj = a + b*yj;
  83
  84     theta = 180.0F*atanf(-zj/(y1 - yj))/pi + ((yj>y1)?180.0F:0.0F);
  85     return 0;
  86 }
  87
  88 // forward kinematics: (theta1, theta2, theta3) -> (x0, y0, z0)
  89 // returned status: 0=OK, -1=non-existing position
  90 int RotatableDeltaSolution::delta_calcForward(float theta1, float theta2, float theta3, float &x0, float &y0, float &z0)
  91 {
  92      float t = (delta_f-delta_e)*tan30/2.0F;
  93      float degrees_to_radians = pi/180.0F;
  94
  95      theta1 *= degrees_to_radians;
  96      theta2 *= degrees_to_radians;
  97      theta3 *= degrees_to_radians;
  98
  99      float y1 = -(t + delta_rf*cosf(theta1));
 100      float z1 = -delta_rf*sinf(theta1);
 101
 102      float y2 = (t + delta_rf*cosf(theta2))*sin30;
 103      float x2 = y2*tan60;
 104      float z2 = -delta_rf*sinf(theta2);
 105
 106      float y3 = (t + delta_rf*cosf(theta3))*sin30;
 107      float x3 = -y3*tan60;
 108      float z3 = -delta_rf*sinf(theta3);
 109
 110      float dnm = (y2-y1)*x3-(y3-y1)*x2;
 111
 112      float w1 = y1*y1 + z1*z1;
 113      float w2 = x2*x2 + y2*y2 + z2*z2;
 114      float w3 = x3*x3 + y3*y3 + z3*z3;
 115
 116      // x = (a1*z + b1)/dnm
 117      float a1 = (z2-z1)*(y3-y1)-(z3-z1)*(y2-y1);
 118      float b1 = -((w2-w1)*(y3-y1)-(w3-w1)*(y2-y1))/2.0F;
 119
 120      // y = (a2*z + b2)/dnm;
 121      float a2 = -(z2-z1)*x3+(z3-z1)*x2;
 122      float b2 = ((w2-w1)*x3 - (w3-w1)*x2)/2.0F;
 123
 124      // a*z^2 + b*z + c = 0
 125      float a = a1*a1 + a2*a2 + dnm*dnm;
 126      float b = 2.0F*(a1*b1 + a2*(b2-y1*dnm) - z1*dnm*dnm);
 127      float c = (b2-y1*dnm)*(b2-y1*dnm) + b1*b1 + dnm*dnm*(z1*z1 - delta_re*delta_re);
 128
 129      // discriminant
 130      float d = b*b - (float)4.0F*a*c;
 131      if (d < 0.0F) return -1; // non-existing point
 132
 133      z0 = -(float)0.5F*(b+sqrtf(d))/a;
 134      x0 = (a1*z0 + b1)/dnm;
 135      y0 = (a2*z0 + b2)/dnm;
 136
 137      z0 += z_calc_offset; //nj
 138      return 0;
 139 }
 140
 141
 142 void RotatableDeltaSolution::init() {
 143
 144         //these are calculated here and not in the config() as these variables can be fine tuned by the user.
 145         z_calc_offset  = (delta_z_offset - tool_offset - delta_ee_offs)*-1.0F;
 146
 147         // This is calculated from the Z_HOME_ANGLE angles after applying forward kinematics, and adding the Z calc offset to it.
 148         z_home_offs    = (((delta_z_offset - tool_offset - delta_ee_offs) - 182.002F) - 0.5F);
 149
 150 }
 151
 152 void RotatableDeltaSolution::cartesian_to_actuator( float cartesian_mm[], float actuator_mm[] )
 153 {
 154         //We need to translate the Cartesian coordinates in mm to the actuator position required in mm so the stepper motor  functions
 155         float alpha_theta = 0.0F;
 156         float beta_theta  = 0.0F;
 157         float gamma_theta = 0.0F;
 158
 159         //Code from Trossen Robotics tutorial, note we put the X axis at the back and not the front of the robot.
 160
 161         float x0 = cartesian_mm[X_AXIS];
 162         float y0 = cartesian_mm[Y_AXIS];
 163         float z_with_offset = cartesian_mm[Z_AXIS] + z_calc_offset; //The delta calculation below places zero at the top.  Subtract the Z offset to make zero at the bottom.
 164
 165         int status =              delta_calcAngleYZ(x0,                    y0,                  z_with_offset, alpha_theta);
 166         if (status == 0) status = delta_calcAngleYZ(x0*cos120 + y0*sin120, y0*cos120-x0*sin120, z_with_offset, beta_theta);  // rotate co-ordinates to +120 deg
 167         if (status == 0) status = delta_calcAngleYZ(x0*cos120 - y0*sin120, y0*cos120+x0*sin120, z_with_offset, gamma_theta);  // rotate co-ordinates to -120 deg
 168
 169         if (status == -1)  //something went wrong,
 170         {
 171             //force to actuator FPD home position as we know this is a valid position
 172             actuator_mm[ALPHA_STEPPER] = 0;
 173             actuator_mm[BETA_STEPPER ] = 0;
 174             actuator_mm[GAMMA_STEPPER] = 0;
 175
 176 //DEBUG CODE, uncomment the following to help determine what may be happening if you are trying to adapt this to your own different roational delta.
 177 //          THEKERNEL->streams->printf("ERROR: Delta calculation fail!  Unable to move to:\n");
 178 //          THEKERNEL->streams->printf("    x= %f\n",cartesian_mm[X_AXIS]);
 179 //          THEKERNEL->streams->printf("    y= %f\n",cartesian_mm[Y_AXIS]);
 180 //          THEKERNEL->streams->printf("    z= %f\n",cartesian_mm[Z_AXIS]);
 181 //          THEKERNEL->streams->printf(" CalcZ= %f\n",z_calc_offset);
 182 //          THEKERNEL->streams->printf(" Offz= %f\n",z_with_offset);
 183           }
 184           else
 185           {
 186             actuator_mm[ALPHA_STEPPER] = alpha_theta;
 187             actuator_mm[BETA_STEPPER ] = beta_theta;
 188             actuator_mm[GAMMA_STEPPER] = gamma_theta;
 189
 190 //                THEKERNEL->streams->printf("cartesian x= %f\n\r",cartesian_mm[X_AXIS]);
 191 //                THEKERNEL->streams->printf(" y= %f\n\r",cartesian_mm[Y_AXIS]);
 192 //                THEKERNEL->streams->printf(" z= %f\n\r",cartesian_mm[Z_AXIS]);
 193 //                THEKERNEL->streams->printf(" Offz= %f\n\r",z_with_offset);
 194 //                THEKERNEL->streams->printf(" delta x= %f\n\r",delta[X_AXIS]);
 195 //                THEKERNEL->streams->printf(" y= %f\n\r",delta[Y_AXIS]);
 196 //                THEKERNEL->streams->printf(" z= %f\n\r",delta[Z_AXIS]);
 197           }
 198
 199 }
 200
 201 void RotatableDeltaSolution::actuator_to_cartesian( float actuator_mm[], float cartesian_mm[] )
 202 {
 203     //Use forward kinematics
 204     delta_calcForward(actuator_mm[ALPHA_STEPPER], actuator_mm[BETA_STEPPER ], actuator_mm[GAMMA_STEPPER], cartesian_mm[X_AXIS], cartesian_mm[Y_AXIS], cartesian_mm[Z_AXIS]);
 205 }
 206
 207 bool RotatableDeltaSolution::set_optional(const arm_options_t& options) {
 208
 209     for(auto &i : options) {
 210         switch(i.first) {
 211             case 'A': delta_e                   = i.second; break;
 212             case 'B': delta_f                   = i.second; break;
 213             case 'C': delta_re                  = i.second; break;
 214             case 'D': delta_rf                  = i.second; break;
 215             case 'E': delta_z_offset            = i.second; break;
 216             case 'F': delta_ee_offs             = i.second; break;
 217             case 'H': tool_offset               = i.second; break;
 218         }
 219     }
 220     init();
 221     return true;
 222 }
 223
 224 bool RotatableDeltaSolution::get_optional(arm_options_t& options) {
 225
 226     // don't report these if none of them are set
 227     if(this->delta_e     != 0.0F || this->delta_f        != 0.0F || this->delta_re               != 0.0F ||
 228        this->delta_rf    != 0.0F || this->delta_z_offset != 0.0F || this->delta_ee_offs          != 0.0F ||
 229        this->tool_offset != 0.0F) {
 230
 231         options['A'] = this->delta_e;
 232         options['B'] = this->delta_f;
 233         options['C'] = this->delta_re;
 234         options['D'] = this->delta_rf;
 235         options['E'] = this->delta_z_offset;
 236         options['F'] = this->delta_ee_offs;
 237         options['H'] = this->tool_offset;
 238     }
 239
 240     return true;
 241 };
 242