Tawanda M / Mbed 2 deprecated CSSE4011_BLE_IMU_Project_rev2

CSSE

Dependencies:   BLE_API eMPL_MPU6050 mbed nRF51822

kalman.c@4:0bb9b3bf75ba, 2015-06-04 (annotated)

Committer:
tmushie
Date:
Thu Jun 04 06:06:28 2015 +0000
Revision:
4:0bb9b3bf75ba
Parent:
3:88db44c43914 
kk

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tmushie 3:88db44c43914 1 #include "kalman.h"
tmushie 3:88db44c43914 2
tmushie 3:88db44c43914 3 // Setup the kalman data struct
tmushie 3:88db44c43914 4 void kalman_init(kalman_data *data)
tmushie 3:88db44c43914 5 {
tmushie 3:88db44c43914 6 data->x1 = 0.0f;
tmushie 3:88db44c43914 7 data->x2 = 0.0f;
tmushie 3:88db44c43914 8 data->x3 = 0.0f;
tmushie 3:88db44c43914 9
tmushie 3:88db44c43914 10 // Init P to diagonal matrix with large values since
tmushie 3:88db44c43914 11 // the initial state is not known
tmushie 3:88db44c43914 12 data->p11 = 1000.0f;
tmushie 3:88db44c43914 13 data->p12 = 0.0f;
tmushie 3:88db44c43914 14 data->p13 = 0.0f;
tmushie 3:88db44c43914 15 data->p21 = 0.0f;
tmushie 3:88db44c43914 16 data->p22 = 1000.0f;
tmushie 3:88db44c43914 17 data->p23 = 0.0f;
tmushie 3:88db44c43914 18 data->p31 = 0.0f;
tmushie 3:88db44c43914 19 data->p32 = 0.0f;
tmushie 3:88db44c43914 20 data->p33 = 1000.0f;
tmushie 3:88db44c43914 21
tmushie 3:88db44c43914 22 data->q1 = Q1;
tmushie 3:88db44c43914 23 data->q2 = Q2;
tmushie 3:88db44c43914 24 data->q3 = Q3;
tmushie 3:88db44c43914 25 data->r1 = R1;
tmushie 3:88db44c43914 26 data->r2 = R2;
tmushie 3:88db44c43914 27 }
tmushie 3:88db44c43914 28
tmushie 3:88db44c43914 29 void kalman_innovate(kalman_data *data, float z1, float z2)
tmushie 3:88db44c43914 30 {
tmushie 3:88db44c43914 31 float y1, y2;
tmushie 3:88db44c43914 32 float a, b, c;
tmushie 3:88db44c43914 33 float sDet;
tmushie 3:88db44c43914 34 float s11, s12, s21, s22;
tmushie 3:88db44c43914 35 float k11, k12, k21, k22, k31, k32;
tmushie 3:88db44c43914 36 float p11, p12, p13, p21, p22, p23, p31, p32, p33;
tmushie 3:88db44c43914 37
tmushie 3:88db44c43914 38 // Step 1
tmushie 3:88db44c43914 39 // x(k) = Fx(k-1) + Bu + w:
tmushie 3:88db44c43914 40 data->x1 = data->x1 + DT*data->x2 - DT*data->x3;
tmushie 3:88db44c43914 41 //x2 = x2;
tmushie 3:88db44c43914 42 //x3 = x3;
tmushie 3:88db44c43914 43
tmushie 3:88db44c43914 44 // Step 2
tmushie 3:88db44c43914 45 // P = FPF'+Q
tmushie 3:88db44c43914 46 a = data->p11 + data->p21*DT - data->p31*DT;
tmushie 3:88db44c43914 47 b = data->p12 + data->p22*DT - data->p32*DT;
tmushie 3:88db44c43914 48 c = data->p13 + data->p23*DT - data->p33*DT;
tmushie 3:88db44c43914 49 data->p11 = a + b*DT - c*DT + data->q1;
tmushie 3:88db44c43914 50 data->p12 = b;
tmushie 3:88db44c43914 51 data->p13 = c;
tmushie 3:88db44c43914 52 data->p21 = data->p21 + data->p22*DT - data->p23*DT;
tmushie 3:88db44c43914 53 data->p22 = data->p22 + data->q2;
tmushie 3:88db44c43914 54 //p23 = p23;
tmushie 3:88db44c43914 55 data->p31 = data->p31 + data->p32*DT - data->p33*DT;
tmushie 3:88db44c43914 56 //p32 = p32;
tmushie 3:88db44c43914 57 data->p33 = data->p33 + data->q3;
tmushie 3:88db44c43914 58
tmushie 3:88db44c43914 59 // Step 3
tmushie 3:88db44c43914 60 // y = z(k) - Hx(k)
tmushie 3:88db44c43914 61 y1 = z1-data->x1;
tmushie 3:88db44c43914 62 y2 = z2-data->x2;
tmushie 3:88db44c43914 63
tmushie 3:88db44c43914 64 // Step 4
tmushie 3:88db44c43914 65 // S = HPT' + R
tmushie 3:88db44c43914 66 s11 = data->p11 + data->r1;
tmushie 3:88db44c43914 67 s12 = data->p12;
tmushie 3:88db44c43914 68 s21 = data->p21;
tmushie 3:88db44c43914 69 s22 = data->p22 + data->r2;
tmushie 3:88db44c43914 70
tmushie 3:88db44c43914 71 // Step 5
tmushie 3:88db44c43914 72 // K = PH*inv(S)
tmushie 3:88db44c43914 73 sDet = 1/(s11*s22 - s12*s21);
tmushie 3:88db44c43914 74 k11 = (data->p11*s22 - data->p12*s21)*sDet;
tmushie 3:88db44c43914 75 k12 = (data->p12*s11 - data->p11*s12)*sDet;
tmushie 3:88db44c43914 76 k21 = (data->p21*s22 - data->p22*s21)*sDet;
tmushie 3:88db44c43914 77 k22 = (data->p22*s11 - data->p21*s12)*sDet;
tmushie 3:88db44c43914 78 k31 = (data->p31*s22 - data->p32*s21)*sDet;
tmushie 3:88db44c43914 79 k32 = (data->p32*s11 - data->p31*s12)*sDet;
tmushie 3:88db44c43914 80
tmushie 3:88db44c43914 81 // Step 6
tmushie 3:88db44c43914 82 // x = x + Ky
tmushie 3:88db44c43914 83 data->x1 = data->x1 + k11*y1 + k12*y2;
tmushie 3:88db44c43914 84 data->x2 = data->x2 + k21*y1 + k22*y2;
tmushie 3:88db44c43914 85 data->x3 = data->x3 + k31*y1 + k32*y2;
tmushie 3:88db44c43914 86
tmushie 3:88db44c43914 87 // Step 7
tmushie 3:88db44c43914 88 // P = (I-KH)P
tmushie 3:88db44c43914 89 p11 = data->p11*(1.0f - k11) - data->p21*k12;
tmushie 3:88db44c43914 90 p12 = data->p12*(1.0f - k11) - data->p22*k12;
tmushie 3:88db44c43914 91 p13 = data->p13*(1.0f - k11) - data->p23*k12;
tmushie 3:88db44c43914 92 p21 = data->p21*(1.0f - k22) - data->p11*k21;
tmushie 3:88db44c43914 93 p22 = data->p22*(1.0f - k22) - data->p12*k21;
tmushie 3:88db44c43914 94 p23 = data->p23*(1.0f - k22) - data->p13*k21;
tmushie 3:88db44c43914 95 p31 = data->p31 - data->p21*k32 - data->p11*k31;
tmushie 3:88db44c43914 96 p32 = data->p32 - data->p22*k32 - data->p12*k31;
tmushie 3:88db44c43914 97 p33 = data->p33 - data->p22*k32 - data->p13*k31;
tmushie 3:88db44c43914 98 data->p11 = p11; data->p12 = p12; data->p13 = p13;
tmushie 3:88db44c43914 99 data->p21 = p21; data->p22 = p22; data->p23 = p23;
tmushie 3:88db44c43914 100 data->p31 = p31; data->p32 = p32; data->p33 = p33;
tmushie 3:88db44c43914 101 }