Diff: kinematics.cpp

Revision:

4:778bc352c47f

Child:

5:01e1e68309ae

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/kinematics.cpp	Sun Oct 07 19:40:12 2018 +0000
@@ -0,0 +1,161 @@
+
+#include "kinematics.h"
+//this implementation has been taken from http://forums.trossenrobotics.com/tutorials/introduction-129/delta-robot-kinematics-3276/
+// robot geometry
+// (look at pics above for explanation)
+extern BufferedSerial buffered_pc;
+Kinematics::Kinematics(Axis* A_, Axis* B_, Axis* C_,calVals calibration_)
+{
+    e = calibration_.e;
+    f = calibration_.f;
+    re = calibration_.re;
+    rf = calibration_.rf;
+    A = A_;
+    B = B_;
+    C = C_;
+    DeltaKinematics<float>::DeltaGeometricDim dim;
+    dim.sb = f;
+    dim.sp = e;
+    dim.L = rf;
+    dim.l = re;
+    dim.h = 60;
+    dim.max_neg_angle = -20;
+    dim.min_parallelogram_angle = 30;
+    
+    DK = new DeltaKinematics<float>(dim);
+
+}
+
+
+// forward kinematics: (theta1, theta2, theta3) -> (x0, y0, z0)
+// returned status: 0=OK, -1=non-existing position
+int Kinematics::delta_calcForward(float theta1, float theta2, float theta3, float &x0, float &y0, float &z0)
+{
+    float t = (f-e)*tan30/2;
+    float dtr = pi/(float)180.0;
+
+    theta1 *= dtr;
+    theta2 *= dtr;
+    theta3 *= dtr;
+
+    float y1 = -(t + rf*cos(theta1));
+    float z1 = -rf*sin(theta1);
+
+    float y2 = (t + rf*cos(theta2))*sin30;
+    float x2 = y2*tan60;
+    float z2 = -rf*sin(theta2);
+
+    float y3 = (t + rf*cos(theta3))*sin30;
+    float x3 = -y3*tan60;
+    float z3 = -rf*sin(theta3);
+
+    float dnm = (y2-y1)*x3-(y3-y1)*x2;
+
+    float w1 = y1*y1 + z1*z1;
+    float w2 = x2*x2 + y2*y2 + z2*z2;
+    float w3 = x3*x3 + y3*y3 + z3*z3;
+
+    // x = (a1*z + b1)/dnm
+    float a1 = (z2-z1)*(y3-y1)-(z3-z1)*(y2-y1);
+    float b1 = -((w2-w1)*(y3-y1)-(w3-w1)*(y2-y1))/2.0;
+
+    // y = (a2*z + b2)/dnm;
+    float a2 = -(z2-z1)*x3+(z3-z1)*x2;
+    float b2 = ((w2-w1)*x3 - (w3-w1)*x2)/2.0;
+
+    // a*z^2 + b*z + c = 0
+    float a = a1*a1 + a2*a2 + dnm*dnm;
+    float b = 2*(a1*b1 + a2*(b2-y1*dnm) - z1*dnm*dnm);
+    float c = (b2-y1*dnm)*(b2-y1*dnm) + b1*b1 + dnm*dnm*(z1*z1 - re*re);
+
+    // discriminant
+    float d = b*b - (float)4.0*a*c;
+    if (d < 0) return -1; // non-existing point
+
+    z0 = -(float)0.5*(b+sqrt(d))/a;
+    x0 = (a1*z0 + b1)/dnm;
+    y0 = (a2*z0 + b2)/dnm;
+    return 0;
+}
+
+// inverse kinematics
+// helper functions, calculates angle theta1 (for YZ-pane)
+int Kinematics::delta_calcAngleYZ(float x0, float y0, float z0, float &theta)
+{
+    float y1 = -0.5 * 0.57735 * f; // f/2 * tg 30
+    y0 -= 0.5 * 0.57735    * e;    // shift center to edge
+    // z = a + b*y
+    float a = (x0*x0 + y0*y0 + z0*z0 +rf*rf - re*re - y1*y1)/(2*z0);
+    float b = (y1-y0)/z0;
+    // discriminant
+    float d = -(a+b*y1)*(a+b*y1)+rf*(b*b*rf+rf);
+    if (d < 0) return -1; // non-existing point
+    float yj = (y1 - a*b - sqrt(d))/(b*b + 1); // choosing outer point
+    float zj = a + b*yj;
+    theta = 180.0*atan(-zj/(y1 - yj))/pi + ((yj>y1)?180.0:0.0);
+    return 0;
+}
+
+// inverse kinematics: (x0, y0, z0) -> (theta1, theta2, theta3)
+// returned status: 0=OK, -1=non-existing position
+int Kinematics::delta_calcInverse(float x0, float y0, float z0, float &theta1, float &theta2, float &theta3)
+{
+    theta1 = theta2 = theta3 = 0;
+    int status = delta_calcAngleYZ(x0, y0, z0, theta1);
+    if (status == 0) status = delta_calcAngleYZ(x0*cos120 + y0*sin120, y0*cos120-x0*sin120, z0, theta2);  // rotate coords to +120 deg
+    if (status == 0) status = delta_calcAngleYZ(x0*cos120 - y0*sin120, y0*cos120+x0*sin120, z0, theta3);  // rotate coords to -120 deg
+    return status;
+}
+
+void Kinematics::activateMotors()
+{
+    C->setMaxVel(15001); // for safety of the linkages, override to go fast!
+    Thread::wait(100);
+    A->setMaxVel(15001);
+    Thread::wait(100);
+    B->setMaxVel(15001);
+    Thread::wait(100);
+    C->odrive->serial_.printf("w axis0.controller.config.vel_limit %f\n",15002);
+    B->odrive->serial_.printf("w axis0.controller.config.vel_limit %f\n",15002);
+    A->odrive->serial_.printf("w axis0.controller.config.vel_limit %f\n",15002);
+
+    int requested_state;
+    requested_state = ODrive::AXIS_STATE_CLOSED_LOOP_CONTROL;
+    A->runState(requested_state);
+    B->runState(requested_state);
+    C->runState(requested_state);
+}
+
+void Kinematics::homeMotors()
+{
+    Thread::wait(1000);
+    A->homeAxis();
+    Thread::wait(1000);
+    B->homeAxis();
+    Thread::wait(1000);
+    C->homeAxis();
+}
+
+int Kinematics::goToPos(float x, float y, float z)
+{
+    //int error = delta_calcInverse(x,y,z,a,b,c);
+    DeltaKinematics<float>::DeltaVector DV = {x,y,z,0,0,0};
+    int  error = DK->CalculateIpk(&DV, 1);
+    //buffered_pc.printf("angles: a:%f , b:%f , c%f\r\n",DV.phi1,DV.phi2,DV.phi3);
+    DV.phi1 = (DV.phi1/180)*pi;
+    DV.phi2 = (DV.phi2/180)*pi;
+    DV.phi3 = (DV.phi3/180)*pi;
+    if(error == 0 ) {
+        A->goAngle(DV.phi1);
+        B->goAngle(DV.phi2);
+        C->goAngle(DV.phi3);
+    }
+    return error;
+}
+
+void Kinematics::goToAngles(float a, float b, float c)
+{
+    A->goAngle(a);
+    B->goAngle(b);
+    C->goAngle(c);
+}
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