altb_pmic / AHRS

AHRS

Dependencies:   Eigen

Dependents:   IndNav_QK3_T265

EKF_RPY.cpp@24:7fe0935b3bd2, 2020-01-06 (annotated)

Committer:
pmic
Date:
Mon Jan 06 10:15:44 2020 +0000
Revision:
24:7fe0935b3bd2
Parent:
23:71996bfe68eb 
Change comments in EKF_RP for state order.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
altb2 21:31e01d3e0143 1 #include "EKF_RPY.h"
altb2 21:31e01d3e0143 2
altb2 21:31e01d3e0143 3 using namespace std;
altb2 21:31e01d3e0143 4 using namespace Eigen;
altb2 21:31e01d3e0143 5
altb2 21:31e01d3e0143 6 EKF_RPY::EKF_RPY(float Ts, float mx0, float my0, float mz0)
altb2 21:31e01d3e0143 7 {
altb2 21:31e01d3e0143 8 this->Ts = Ts;
altb2 22:495a419e474c 9 set_para();
altb2 21:31e01d3e0143 10 m0 << mx0, my0, mz0;
altb2 21:31e01d3e0143 11 reset();
altb2 21:31e01d3e0143 12 }
altb2 22:495a419e474c 13
altb2 22:495a419e474c 14 EKF_RPY::EKF_RPY(float Ts)
altb2 21:31e01d3e0143 15 {
altb2 21:31e01d3e0143 16 this->Ts = Ts;
altb2 22:495a419e474c 17 set_para();
altb2 22:495a419e474c 18 reset();
altb2 22:495a419e474c 19 }
altb2 22:495a419e474c 20
altb2 22:495a419e474c 21 EKF_RPY::~EKF_RPY() {}
altb2 22:495a419e474c 22
altb2 22:495a419e474c 23 void EKF_RPY::set_para()
altb2 22:495a419e474c 24 {
altb2 21:31e01d3e0143 25 /* [n_gyro; n_v; n_b_g] */
altb2 22:495a419e474c 26 var_fx << 0.1f, 0.1f, 0.1f, 0.002f, 0.002f, 0.002f, 0.002f, 0.002f;
altb2 21:31e01d3e0143 27 /* [n_acc; n_mag] */
altb2 22:495a419e474c 28 var_gy << 40.0f, 40.0f, 1.0f, 1.0f;
altb2 22:495a419e474c 29 rho = 1.0f;
altb2 21:31e01d3e0143 30 kv = 0.5f; /* k1/m */
altb2 21:31e01d3e0143 31 g = 9.81f;
altb2 23:71996bfe68eb 32 scale_P0 = 1000.0f;
altb2 21:31e01d3e0143 33 }
altb2 21:31e01d3e0143 34
altb2 21:31e01d3e0143 35 void EKF_RPY::reset()
altb2 21:31e01d3e0143 36 {
altb2 21:31e01d3e0143 37 u.setZero();
altb2 21:31e01d3e0143 38 y.setZero();
altb2 21:31e01d3e0143 39 x.setZero();
altb2 21:31e01d3e0143 40 update_angles();
altb2 21:31e01d3e0143 41 calc_F();
altb2 21:31e01d3e0143 42 calc_H();
altb2 21:31e01d3e0143 43 initialize_Q();
altb2 21:31e01d3e0143 44 initialize_R();
altb2 21:31e01d3e0143 45 K.setZero();
altb2 21:31e01d3e0143 46 I.setIdentity();
altb2 22:495a419e474c 47 e.setZero();
altb2 23:71996bfe68eb 48 P = scale_P0 * I;
altb2 23:71996bfe68eb 49 }
altb2 23:71996bfe68eb 50
altb2 23:71996bfe68eb 51 void EKF_RPY::increase_diag_P()
altb2 23:71996bfe68eb 52 {
altb2 23:71996bfe68eb 53 P = P + scale_P0 * I;
altb2 22:495a419e474c 54 }
altb2 22:495a419e474c 55
altb2 22:495a419e474c 56 void EKF_RPY::set_m0(float mx0, float my0, float mz0)
altb2 22:495a419e474c 57 {
altb2 22:495a419e474c 58 m0 << mx0, my0, mz0;
altb2 21:31e01d3e0143 59 }
altb2 21:31e01d3e0143 60
altb2 21:31e01d3e0143 61 float EKF_RPY::get_est_state(uint8_t i)
altb2 21:31e01d3e0143 62 {
altb2 21:31e01d3e0143 63 /* x = [ang; v; b_g] = [0: phi
altb2 21:31e01d3e0143 64 1: theta
altb2 21:31e01d3e0143 65 2: psi
pmic 24:7fe0935b3bd2 66 3: vx
pmic 24:7fe0935b3bd2 67 4: vy
pmic 24:7fe0935b3bd2 68 5: b_gx
pmic 24:7fe0935b3bd2 69 6: b_gy
pmic 24:7fe0935b3bd2 70 7: b_gz] */
altb2 21:31e01d3e0143 71 return x(i);
altb2 21:31e01d3e0143 72 }
altb2 21:31e01d3e0143 73
altb2 21:31e01d3e0143 74 void EKF_RPY::update(float gyro_x, float gyro_y, float gyro_z, float accel_x, float accel_y, float magnet_x, float magnet_y)
altb2 21:31e01d3e0143 75 {
altb2 21:31e01d3e0143 76 u << gyro_x, gyro_y, gyro_z;
altb2 21:31e01d3e0143 77 y << accel_x, accel_y, magnet_x, magnet_y;
altb2 21:31e01d3e0143 78 update_angles();
altb2 21:31e01d3e0143 79
altb2 21:31e01d3e0143 80 calc_F();
altb2 21:31e01d3e0143 81 calc_H();
altb2 21:31e01d3e0143 82 calc_Q();
altb2 21:31e01d3e0143 83
altb2 21:31e01d3e0143 84 x = fxd();
altb2 21:31e01d3e0143 85 P = F * P * F.transpose() + Q;
altb2 22:495a419e474c 86 e = y - gy();
altb2 21:31e01d3e0143 87
altb2 22:495a419e474c 88 /* inversion faster 356 mus < 432 mus recursion */
altb2 21:31e01d3e0143 89 K = P * H.transpose() * ( H * P * H.transpose() + R ).inverse();
altb2 22:495a419e474c 90 x = x + K * e;
altb2 22:495a419e474c 91 P = (I - K * H) * P;
altb2 21:31e01d3e0143 92
altb2 22:495a419e474c 93 /* only valid if R is diagonal (uncorrelated noise) */
altb2 22:495a419e474c 94 /*
altb2 22:495a419e474c 95 for(uint8_t i = 0; i < 4; i++) {
altb2 22:495a419e474c 96 K.col(i) = ( P * (H.row(i)).transpose() ) / ( H.row(i) * P * (H.row(i)).transpose() + R(i,i) );
altb2 22:495a419e474c 97 x = x + K.col(i) * e(i);
altb2 22:495a419e474c 98 P = (I - K.col(i)*H.row(i)) * P;
altb2 22:495a419e474c 99 }
altb2 22:495a419e474c 100 */
altb2 21:31e01d3e0143 101 }
altb2 21:31e01d3e0143 102
altb2 21:31e01d3e0143 103 void EKF_RPY::update_angles()
altb2 21:31e01d3e0143 104 {
altb2 21:31e01d3e0143 105 s1 = sinf(x(0));
altb2 21:31e01d3e0143 106 c1 = cosf(x(0));
altb2 21:31e01d3e0143 107 s2 = sinf(x(1));
altb2 21:31e01d3e0143 108 c2 = cosf(x(1));
altb2 21:31e01d3e0143 109 s3 = sinf(x(2));
altb2 21:31e01d3e0143 110 c3 = cosf(x(2));
altb2 21:31e01d3e0143 111 }
altb2 21:31e01d3e0143 112
altb2 21:31e01d3e0143 113 void EKF_RPY::calc_F()
altb2 21:31e01d3e0143 114 {
altb2 21:31e01d3e0143 115 F << Ts*(c1*s2*(u(1) - x(6)) - s1*s2*(u(2) - x(7)))/c2 + 1.0f, Ts*(c1*(u(2) - x(7)) + s1*(u(1) - x(6)))/(c2*c2), 0.0f, 0.0f, 0.0f, -Ts, -Ts*s1*s2/c2, -Ts*c1*s2/c2,
altb2 21:31e01d3e0143 116 -Ts*(c1*(u(2) - x(7)) + s1*(u(1) - x(6))), 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, -Ts*c1, Ts*s1,
altb2 21:31e01d3e0143 117 Ts*(c1*(u(1) - x(6)) - s1*(u(2) - x(7)))/c2, Ts*(c1*(u(2) - x(7)) + s1*(u(1) - x(6)))*s2/(c2*c2), 1.0f, 0.0f, 0.0f, 0.0f, -Ts*s1/c2, -Ts*c1/c2,
altb2 21:31e01d3e0143 118 0.0f, Ts*c2*g, 0.0f, 1.0f - Ts*kv, Ts*(u(2) - x(7)), 0.0f, 0.0f, -Ts*x(4),
altb2 21:31e01d3e0143 119 -Ts*c1*c2*g, Ts*g*s1*s2, 0.0f, -Ts*(u(2) - x(7)), 1.0f - Ts*kv, 0.0f, 0.0f, Ts*x(3),
altb2 21:31e01d3e0143 120 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
altb2 21:31e01d3e0143 121 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f,
altb2 21:31e01d3e0143 122 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f;
altb2 21:31e01d3e0143 123 }
altb2 21:31e01d3e0143 124
altb2 21:31e01d3e0143 125 void EKF_RPY::calc_H()
altb2 21:31e01d3e0143 126 {
altb2 21:31e01d3e0143 127 H << 0.0f, 0.0f, 0.0f, -kv, u(2) - x(7), 0.0f, 0.0f, -x(4),
altb2 21:31e01d3e0143 128 0.0f, 0.0f, 0.0f, x(7) - u(2), -kv, 0.0f, 0.0f, x(3),
altb2 21:31e01d3e0143 129 0.0f, - c2*m0(2) - c3*m0(0)*s2 - m0(1)*s2*s3, c2*(c3*m0(1) - m0(0)*s3), 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
altb2 21:31e01d3e0143 130 m0(0)*(s1*s3 + c1*c3*s2) - m0(1)*(c3*s1 - c1*s2*s3) + c1*c2*m0(2), s1*(c2*c3*m0(0) - m0(2)*s2 + c2*m0(1)*s3), - m0(0)*(c1*c3 + s1*s2*s3) - m0(1)*(c1*s3 - c3*s1*s2), 0.0f, 0.0f, 0.0f, 0.0f, 0.0f;
altb2 21:31e01d3e0143 131 }
altb2 21:31e01d3e0143 132
altb2 21:31e01d3e0143 133 void EKF_RPY::initialize_R()
altb2 21:31e01d3e0143 134 {
altb2 21:31e01d3e0143 135 R << rho*var_gy(0)/Ts, 0.0f, 0.0f, 0.0f,
altb2 21:31e01d3e0143 136 0.0f, rho*var_gy(1)/Ts, 0.0f, 0.0f,
altb2 21:31e01d3e0143 137 0.0f, 0.0f, rho*var_gy(2)/Ts, 0.0f,
altb2 21:31e01d3e0143 138 0.0f, 0.0f, 0.0f, rho*var_gy(3)/Ts;
altb2 21:31e01d3e0143 139 }
altb2 21:31e01d3e0143 140
altb2 21:31e01d3e0143 141 void EKF_RPY::initialize_Q()
altb2 21:31e01d3e0143 142 {
altb2 21:31e01d3e0143 143 Q << Ts*(var_fx(0) + (c1*c1*var_fx(2) + s1*s1*var_fx(1))*s2*s2/(c2*c2)), Ts*(var_fx(1) - var_fx(2))*c1*s1*s2/c2, Ts*(c1*c1*var_fx(2) + s1*s1*var_fx(1))*s2/(c2*c2), 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
altb2 21:31e01d3e0143 144 Ts*(var_fx(1) - var_fx(2))*c1*s1*s2/c2, Ts*(var_fx(1)*c1*c1 + var_fx(2)*s1*s1), Ts*(var_fx(1) - var_fx(2))*c1*s1/c2, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
altb2 21:31e01d3e0143 145 Ts*(c1*c1*var_fx(2) + s1*s1*var_fx(1))*s2/(c2*c2), Ts*(var_fx(1) - var_fx(2))*c1*s1/c2, Ts*(c1*c1*var_fx(2) + s1*s1*var_fx(1))/(c2*c2), 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
altb2 21:31e01d3e0143 146 0.0f, 0.0f, 0.0f, Ts*var_fx(3), 0.0f, 0.0f, 0.0f, 0.0f,
altb2 21:31e01d3e0143 147 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(4), 0.0f, 0.0f, 0.0f,
altb2 21:31e01d3e0143 148 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(5), 0.0f, 0.0f,
altb2 21:31e01d3e0143 149 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(6), 0.0f,
altb2 21:31e01d3e0143 150 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(7);
altb2 21:31e01d3e0143 151 }
altb2 21:31e01d3e0143 152
altb2 21:31e01d3e0143 153 void EKF_RPY::calc_Q()
altb2 21:31e01d3e0143 154 {
altb2 21:31e01d3e0143 155 Q(0,0) = Ts*(var_fx(0) + (c1*c1*var_fx(2) + s1*s1*var_fx(1))*s2*s2/(c2*c2));
altb2 21:31e01d3e0143 156 Q(0,1) = Ts*(var_fx(1) - var_fx(2))*c1*s1*s2/c2;
altb2 21:31e01d3e0143 157 Q(0,2) = Ts*(c1*c1*var_fx(2) + s1*s1*var_fx(1))*s2/(c2*c2);
altb2 21:31e01d3e0143 158 Q(1,0) = Q(0,1);
altb2 21:31e01d3e0143 159 Q(1,1) = Ts*(var_fx(1)*c1*c1 + var_fx(2)*s1*s1);
altb2 21:31e01d3e0143 160 Q(1,2) = Ts*(var_fx(1) - var_fx(2))*c1*s1/c2;
altb2 21:31e01d3e0143 161 Q(2,0) = Q(0,2);
altb2 21:31e01d3e0143 162 Q(2,1) = Q(1,2);
altb2 21:31e01d3e0143 163 Q(2,2) = Ts*(c1*c1*var_fx(2) + s1*s1*var_fx(1))/(c2*c2);
altb2 21:31e01d3e0143 164 }
altb2 21:31e01d3e0143 165
altb2 21:31e01d3e0143 166 Matrix <float, 8, 1> EKF_RPY::fxd()
altb2 21:31e01d3e0143 167 {
altb2 21:31e01d3e0143 168 Matrix <float, 8, 1> retval;
altb2 21:31e01d3e0143 169 retval << x(0) + Ts*(u(0) - x(5) + (c1*s2*(u(2) - x(7)))/c2 + (s1*s2*(u(1) - x(6)))/c2),
altb2 21:31e01d3e0143 170 x(1) + Ts*(c1*(u(1) - x(6)) - s1*(u(2) - x(7))),
altb2 21:31e01d3e0143 171 x(2) + Ts*((c1*(u(2) - x(7)))/c2 + (s1*(u(1) - x(6)))/c2),
altb2 21:31e01d3e0143 172 x(3) + Ts*(g*s2 - kv*x(3) + x(4)*(u(2) - x(7))),
altb2 21:31e01d3e0143 173 x(4) - Ts*(kv*x(4) + x(3)*(u(2) - x(7)) + c2*g*s1),
altb2 21:31e01d3e0143 174 x(5),
altb2 21:31e01d3e0143 175 x(6),
altb2 21:31e01d3e0143 176 x(7);
altb2 21:31e01d3e0143 177 return retval;
altb2 21:31e01d3e0143 178 }
altb2 21:31e01d3e0143 179
altb2 21:31e01d3e0143 180 Matrix <float, 4, 1> EKF_RPY::gy()
altb2 21:31e01d3e0143 181 {
altb2 21:31e01d3e0143 182 Matrix <float, 4, 1> retval;
altb2 21:31e01d3e0143 183 retval << x(4)*(u(2) - x(7)) - kv*x(3),
altb2 21:31e01d3e0143 184 - kv*x(4) - x(3)*(u(2) - x(7)),
altb2 21:31e01d3e0143 185 - m0(2)*s2 + c2*c3*m0(0) + c2*m0(1)*s3,
altb2 21:31e01d3e0143 186 - m0(0)*(c1*s3 - c3*s1*s2) + m0(1)*(c1*c3 + s1*s2*s3) + c2*m0(2)*s1;
altb2 21:31e01d3e0143 187 return retval;
altb2 21:31e01d3e0143 188 }
altb2 21:31e01d3e0143 189