scarakins axis follow problem in -x and -y zone

        *iflags = 0;            if (joint[1] < 90)                      *iflags = 1; than in Inverse: [code]    /* joint 1 angle needed to make arm length match sqrt(rsq) */     cc = (rsq - D2*D2 - D4*D4) / (2*D2*D4);     if(cc < -1) cc = -1;     if(cc > 1) cc = 1;     q1 = acos(cc);     if (*iflags)     q1 = -q1; but not understand why exactly seems x and c axis try to moove into undesired point (with estop obtain follow error on joint 0 and joint3 so X and C axis) ... these not happens in positive area +X and +Y or +X and -Y or -X and -Y ... only during moovement trought -Y to +Y if I'm on -X area ..... but is these logical?  a3 or C axis not change angle during these motion from -n to +n or inverse .... any suggestion is appreciate p.s.: axis limit for test is set to +6000mm and -6000 mm... but robot can reach only 900mm. joint limit is set to +720° and -720° so is not a limit problem ...

static int scaraKinematicsInverse(const EmcPose * world,                                   double * joint,                                   const KINEMATICS_INVERSE_FLAGS * iflags,                                   KINEMATICS_FORWARD_FLAGS * fflags) {     double a3;     double q0, q1;     double xt, yt, xt1, yt1, rsq, cc;     double x, y, z, c;     x = world->tran.x;     y = world->tran.y;     z = world->tran.z;     c = world->c;     /* convert degrees to radians */     a3 = c * ( PM_PI / 180 );     /* center of end effector (correct for D6) */     xt = x - D6*cos(a3);     yt = y - D6*sin(a3);     xt1 = xt;     yt1 = yt;     /* horizontal distance (squared) from end effector centerline         to main column centerline */     rsq = xt*xt + yt*yt;     /* joint 1 angle needed to make arm length match sqrt(rsq) */     cc = (rsq - D2*D2 - D4*D4) / (2*D2*D4);     if(cc < -1) cc = -1;     if(cc > 1) cc = 1;     q1 = acos(cc);     if (*iflags)         q1 = -q1;     /* angle to end effector */     q0 = atan2(yt, xt);     /* end effector coords in inner arm coord system */     xt = D2 + D4*cos(q1);     yt = D4*sin(q1);     /* inner arm angle */     //q0 = q0 - atan2(yt, xt);     if((xt1<0) && (yt1>=0)){q0 = q0 - atan2(yt, xt) - 2*M_PI;}     else{q0 = q0 - atan2(yt, xt);}     /* q0 and q1 are still in radians. convert them to degrees */     q0 = q0 * (180 / PM_PI);     q1 = q1 * (180 / PM_PI);     joint[0] = q0;     joint[1] = q1;     joint[2] = D1 + D3 - D5 - z;     joint[3] = c - ( q0 + q1);     joint[4] = world->a;     joint[5] = world->b;     *fflags = 0;     return (0); } // scaraKinematicsInverse()

#define DEFAULT_D1 490 #define DEFAULT_D2 340 #define DEFAULT_D3  50 #define DEFAULT_D4 250 #define DEFAULT_D5  50 #define DEFAULT_D6  50

sudo halcompile --install <your_path>/scarakins.c

sudo apt install linuxcnc-dev

git checkout 2.9