Diff: Kalman/Kalman.cpp

Revision:

0:fbfafa6bf5f9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Kalman/Kalman.cpp	Fri Apr 20 21:32:24 2012 +0000
@@ -0,0 +1,262 @@
+//***************************************************************************************
+//Kalman Filter implementation
+//***************************************************************************************
+#include "Kalman.h"
+#include "rtos.h"
+#include "RFSRF05.h"
+//#include "MatrixMath.h"
+//#include "Matrix.h"
+#include "math.h"
+#include "globals.h"
+#include "motors.h"
+#include "system.h"
+#include "geometryfuncs.h"
+
+#include <tvmet/Matrix.h>
+#include <tvmet/Vector.h>
+using namespace tvmet;
+DigitalOut led1(LED1);
+DigitalOut led2(LED2);
+DigitalOut led3(LED3);
+DigitalOut led4(LED4);
+
+
+Kalman::Kalman(Motors &motorsin) :
+        sonararray(p10,p21,p22,p23,p24,p25,p26,p5,p6,p7,p8,p9),
+        motors(motorsin),
+        predictthread(predictloopwrapper, this, osPriorityNormal, 512),
+        predictticker( SIGTICKARGS(predictthread, 0x1) ),
+//        sonarthread(sonarloopwrapper, this, osPriorityNormal, 256),
+//        sonarticker( SIGTICKARGS(sonarthread, 0x1) ),
+        updatethread(updateloopwrapper, this, osPriorityNormal, 2048) {
+
+    //Initilising matrices
+
+    // X = x, y, theta;
+    X = 0.5, 0, 0;
+
+    P = 1, 0, 0,
+        0, 1, 0,
+        0, 0, 0.04;
+
+    //Q = 0.002, 0, 0, //temporary matrix, Use dt!
+    //    0, 0.002, 0,
+    //    0, 0, 0.002;
+
+    //measurment variance R is provided by each sensor when calling runupdate
+
+    //attach callback
+    sonararray.callbackobj = (DummyCT*)this;
+    sonararray.mcallbackfunc = (void (DummyCT::*)(int beaconnum, float distance, float variance)) &Kalman::runupdate;
+
+
+    predictticker.start(20);
+//    sonarticker.start(50);
+
+
+}
+
+
+void Kalman::predictloop() {
+
+    float lastleft = 0;
+    float lastright = 0;
+
+    while (1) {
+        Thread::signal_wait(0x1);
+        led1 = !led1;
+        
+        int leftenc = motors.getEncoder1();
+        int rightenc = motors.getEncoder2();
+        
+        float dleft = motors.encoderToDistance(leftenc-lastleft)/1000.0f;
+        float dright = motors.encoderToDistance(rightenc-lastright)/1000.0f;
+
+        lastleft = leftenc;
+        lastright = rightenc;
+
+
+        //The below calculation are in body frame (where +x is forward)
+        float dxp, dyp,d,r;
+        float thetap = (dright - dleft)*PI / (float(robotCircumference)/1000.0f);
+        if (abs(thetap) < 0.02) { //if the rotation through the integration step is small, approximate with a straight line to avoid numerical error
+            d = (dright + dleft)/2.0f;
+            dxp = d*cos(thetap/2.0f);
+            dyp = d*sin(thetap/2.0f);
+
+        } else { //calculate circle arc
+            //float r = (right + left) / (4.0f * PI * thetap);
+            r = (dright + dleft) / (2.0f*thetap);
+            dxp = abs(r)*sin(thetap);
+            dyp = r - r*cos(thetap);
+        }
+
+        statelock.lock();
+
+        //rotating to cartesian frame and updating state
+        X(0) += dxp * cos(X(2)) - dyp * sin(X(2));
+        X(1) += dxp * sin(X(2)) + dyp * cos(X(2));
+        X(2) = rectifyAng(X(2) + thetap);
+
+        //Linearising F around X
+        Matrix<float, 3, 3> F;
+        F = 1, 0, (dxp * -sin(X(2)) - dyp * cos(X(2))),
+            0, 1, (dxp * cos(X(2)) - dyp * sin(X(2))),
+            0, 0, 1;
+
+        //Generating forward and rotational variance
+        float varfwd = fwdvarperunit * (dright + dleft) / 2.0f;
+        float varang = varperang * thetap;
+        float varxydt = xyvarpertime * PREDICTPERIOD;
+        float varangdt = angvarpertime * PREDICTPERIOD;
+        
+        //Rotating into cartesian frame
+        Matrix<float, 2, 2> Qsub,Qsubrot,Qrot;
+        Qsub = varfwd + varxydt, 0,
+               0, varxydt;
+               
+        Qrot = Rotmatrix(X(2));
+               
+        Qsubrot = Qrot * Qsub * trans(Qrot);
+
+        //Generate Q
+        Matrix<float, 3, 3> Q;//(Qsubrot);
+        Q = Qsubrot(0,0), Qsubrot(0,1), 0,
+            Qsubrot(1,0), Qsubrot(1,1), 0,
+            0, 0, varang + varangdt;
+
+        P = F * P * trans(F) + Q;
+
+        statelock.unlock();
+        //Thread::wait(PREDICTPERIOD);
+
+        //cout << "predict" << X << endl;
+        //cout << P << endl;
+    }
+}
+
+//void Kalman::sonarloop() {
+//    while (1) {
+//        Thread::signal_wait(0x1);
+//        sonararray.startRange();
+//    }
+//}
+
+
+void Kalman::runupdate(measurement_t type, float value, float variance) {
+    //printf("beacon %d dist %f\r\n", sonarid, dist);
+    //led2 = !led2;
+
+    measurmentdata* measured = (measurmentdata*)measureMQ.alloc();
+    if (measured) {
+        measured->mtype = type;
+        measured->value = value;
+        measured->variance = variance;
+
+        osStatus putret = measureMQ.put(measured);
+        if (putret)
+            led4 = 1;
+        //    printf("putting in MQ error code %#x\r\n", putret);
+    } else {
+        led4 = 1;
+        //printf("MQalloc returned NULL ptr\r\n");
+    }
+
+}
+
+void Kalman::updateloop() {
+    measurement_t type;
+    float value,variance,rbx,rby,expecdist,Y;
+    float dhdx,dhdy;
+    bool aborton2stddev = false;
+
+    Matrix<float, 1, 3> H;
+
+    float S;
+    Matrix<float, 3, 3> I3( identity< Matrix<float, 3, 3> >() );
+
+
+    while (1) {
+        led2 = !led2;
+
+        osEvent evt = measureMQ.get();
+
+        if (evt.status == osEventMail) {
+
+            measurmentdata &measured = *(measurmentdata*)evt.value.p;
+            type = measured.mtype; //Note, may support more measurment types than sonar in the future!
+            value = measured.value;
+            variance = measured.variance;
+
+            // don't forget to free the memory
+            measureMQ.free(&measured);
+
+            if (type <= maxmeasure) {
+
+                if (type <= SONAR3) {
+
+                    float dist = value / 1000.0f; //converting to m from mm
+                    int sonarid = type;
+                    aborton2stddev = false; 
+
+                    statelock.lock();
+                    SonarMeasures[sonarid] = dist; //update the current sonar readings
+
+                    rbx = X(0) - beaconpos[sonarid].x/1000.0f;
+                    rby = X(1) - beaconpos[sonarid].y/1000.0f;
+
+                    expecdist = hypot(rbx, rby);//sqrt(rbx*rbx + rby*rby);
+                    Y = dist - expecdist;
+
+                    dhdx = rbx / expecdist;
+                    dhdy = rby / expecdist;
+
+                    H = dhdx, dhdy, 0;
+
+                } else if (type <= IR3) {
+                  
+                    aborton2stddev = false;
+                    int IRidx = type-3;
+                    
+                    statelock.lock();
+                    IRMeasures[IRidx] = value;
+                    
+                    rbx = X(0) - beaconpos[IRidx].x/1000.0f;
+                    rby = X(1) - beaconpos[IRidx].y/1000.0f;
+                    
+                    float expecang = atan2(-rbx, -rby) - X(2);
+                    //printf("expecang: %0.4f, value: %0.4f \n\r", expecang*180/PI,value*180/PI);
+                    Y = rectifyAng(value + expecang);
+                    
+                    float dstsq = rbx*rbx + rby*rby;
+                    H = -rby/dstsq, rbx/dstsq, -1;
+                }
+
+                Matrix<float, 3, 1> PH (P * trans(H));
+                S = (H * PH)(0,0) + variance;
+
+                if (aborton2stddev && Y*Y > 4 * S) {
+                    statelock.unlock();
+                    continue;
+                }
+
+                Matrix<float, 3, 1> K (PH * (1/S));
+
+                //Updating state
+                X += col(K, 0) * Y;
+                X(2) = rectifyAng(X(2));
+
+                P = (I3 - K * H) * P;
+
+                statelock.unlock();
+
+            }
+
+        } else {
+            led4 = 1;
+            //printf("ERROR: in updateloop, code %#x", evt);
+        }
+
+    }
+
+}
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