altb_pmic / Mbed 2 deprecated Test_ekf

Testing ekf implementation for Quadro_1.

Dependencies:   mbed Eigen

EKF_RP.cpp@19:ccb6fc8bf872, 2019-10-28 (annotated)

Committer:
pmic
Date:
Mon Oct 28 12:08:15 2019 +0000
Revision:
19:ccb6fc8bf872
Parent:
18:f374ca9a3e75
Child:
20:0227c82a78c2
Add increase_diag_P function so diag(P) can be increased while arming copter.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
pmic 0:a0e9705be9c4 1 #include "EKF_RP.h"
pmic 0:a0e9705be9c4 2
pmic 0:a0e9705be9c4 3 using namespace std;
pmic 0:a0e9705be9c4 4 using namespace Eigen;
pmic 0:a0e9705be9c4 5
pmic 0:a0e9705be9c4 6 EKF_RP::EKF_RP(float Ts)
pmic 0:a0e9705be9c4 7 {
pmic 0:a0e9705be9c4 8 this->Ts = Ts;
pmic 0:a0e9705be9c4 9 /* [n_gyro; n_b_g; n_v] */
pmic 13:2e03d9c03409 10 var_fx << 0.1f, 0.1f, 0.002f, 0.002f, 0.002f, 0.002f;
pmic 0:a0e9705be9c4 11 /* [n_acc] */
pmic 13:2e03d9c03409 12 var_gy << 40.0f, 40.0f;
pmic 13:2e03d9c03409 13 rho = 1.0f;
pmic 5:676cbc33c81b 14 kv = 0.5f; /* k1/m */
pmic 5:676cbc33c81b 15 g = 9.81f;
pmic 19:ccb6fc8bf872 16 scale_P0 = 1000000.0f;
pmic 0:a0e9705be9c4 17 reset();
pmic 0:a0e9705be9c4 18 }
pmic 0:a0e9705be9c4 19
pmic 0:a0e9705be9c4 20 EKF_RP::~EKF_RP() {}
pmic 0:a0e9705be9c4 21
pmic 0:a0e9705be9c4 22 void EKF_RP::reset()
pmic 0:a0e9705be9c4 23 {
pmic 0:a0e9705be9c4 24 u.setZero();
pmic 0:a0e9705be9c4 25 y.setZero();
pmic 0:a0e9705be9c4 26 x.setZero();
pmic 4:e50e18eac72b 27 update_angles();
pmic 4:e50e18eac72b 28 calc_F();
pmic 4:e50e18eac72b 29 calc_H();
pmic 0:a0e9705be9c4 30 initialize_Q();
pmic 0:a0e9705be9c4 31 initialize_R();
pmic 0:a0e9705be9c4 32 K.setZero();
pmic 0:a0e9705be9c4 33 I.setIdentity();
pmic 13:2e03d9c03409 34 e.setZero();
pmic 19:ccb6fc8bf872 35 P.setZero();
pmic 19:ccb6fc8bf872 36 increase_diag_P();
pmic 19:ccb6fc8bf872 37 }
pmic 19:ccb6fc8bf872 38
pmic 19:ccb6fc8bf872 39 void EKF_RP::increase_diag_P()
pmic 19:ccb6fc8bf872 40 {
pmic 19:ccb6fc8bf872 41 P = P + scale_P0 * I;
pmic 0:a0e9705be9c4 42 }
pmic 0:a0e9705be9c4 43
pmic 4:e50e18eac72b 44 float EKF_RP::get_est_state(uint8_t i)
pmic 4:e50e18eac72b 45 {
pmic 7:bcbcc23983de 46 /* x = [ang; v; b_g] = [0: phi
pmic 7:bcbcc23983de 47 1: theta
pmic 7:bcbcc23983de 48 2: vx
pmic 7:bcbcc23983de 49 3: vy
pmic 7:bcbcc23983de 50 4: b_gx
pmic 7:bcbcc23983de 51 5: b_gy] */
pmic 4:e50e18eac72b 52 return x(i);
pmic 4:e50e18eac72b 53 }
pmic 4:e50e18eac72b 54
pmic 0:a0e9705be9c4 55 void EKF_RP::update(float gyro_x, float gyro_y, float accel_x, float accel_y)
pmic 0:a0e9705be9c4 56 {
pmic 4:e50e18eac72b 57 u << gyro_x, gyro_y;
pmic 4:e50e18eac72b 58 y << accel_x, accel_y;
pmic 4:e50e18eac72b 59 update_angles();
pmic 0:a0e9705be9c4 60
pmic 4:e50e18eac72b 61 calc_F();
pmic 5:676cbc33c81b 62 // calc_H(); /* H remains constant */
pmic 4:e50e18eac72b 63 calc_Q();
pmic 0:a0e9705be9c4 64
pmic 4:e50e18eac72b 65 x = fxd();
pmic 5:676cbc33c81b 66 P = F * P * F.transpose() + Q;
pmic 13:2e03d9c03409 67 e = y - gy();
pmic 0:a0e9705be9c4 68
pmic 17:1d98928f7681 69 /* inversion faster 184 mus < 207 mus recursion */
pmic 17:1d98928f7681 70 K = P * H.transpose() * ( H * P * H.transpose() + R ).inverse();
pmic 17:1d98928f7681 71 x = x + K * e;
pmic 17:1d98928f7681 72 P = (I - K * H) * P;
pmic 15:53485bd1ff28 73
pmic 13:2e03d9c03409 74 /* only valid if R is diagonal (uncorrelated noise) */
pmic 17:1d98928f7681 75 /*
pmic 16:c39e084f05ed 76 for(uint8_t i = 0; i < 2; i++) {
pmic 16:c39e084f05ed 77 K.col(i) = ( P * (H.row(i)).transpose() ) / ( H.row(i) * P * (H.row(i)).transpose() + R(i,i) );
pmic 16:c39e084f05ed 78 x = x + K.col(i) * e(i);
pmic 16:c39e084f05ed 79 P = (I - K.col(i)*H.row(i)) * P;
pmic 17:1d98928f7681 80 }
pmic 17:1d98928f7681 81 */
pmic 0:a0e9705be9c4 82 }
pmic 0:a0e9705be9c4 83
pmic 0:a0e9705be9c4 84 void EKF_RP::update_angles()
pmic 0:a0e9705be9c4 85 {
pmic 5:676cbc33c81b 86 s1 = sinf(x(0));
pmic 5:676cbc33c81b 87 c1 = cosf(x(0));
pmic 5:676cbc33c81b 88 s2 = sinf(x(1));
pmic 5:676cbc33c81b 89 c2 = cosf(x(1));
pmic 0:a0e9705be9c4 90 }
pmic 0:a0e9705be9c4 91
pmic 4:e50e18eac72b 92 void EKF_RP::calc_F()
pmic 0:a0e9705be9c4 93 {
pmic 7:bcbcc23983de 94 F << Ts*c1*s2*(u(1) - x(3))/c2 + 1.0f, Ts*s1*(u(1) - x(3))/(c2*c2), -Ts, -Ts*s1*s2/c2, 0.0f, 0.0f,
pmic 7:bcbcc23983de 95 -Ts*s1*(u(1) - x(3)), 1.0f, 0.0f, -Ts*c1, 0.0f, 0.0f,
pmic 7:bcbcc23983de 96 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
pmic 7:bcbcc23983de 97 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
pmic 7:bcbcc23983de 98 0.0f, Ts*c2*g, 0.0f, 0.0f, 1.0f - Ts*kv, 0.0f,
pmic 7:bcbcc23983de 99 -Ts*c1*c2*g, Ts*g*s1*s2, 0.0f, 0.0f, 0.0f, 1.0f - Ts*kv;
pmic 0:a0e9705be9c4 100 }
pmic 0:a0e9705be9c4 101
pmic 4:e50e18eac72b 102 void EKF_RP::calc_H()
pmic 0:a0e9705be9c4 103 {
pmic 5:676cbc33c81b 104 H << 0.0f, 0.0f, 0.0f, 0.0f, -kv, 0.0f,
pmic 5:676cbc33c81b 105 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -kv;
pmic 0:a0e9705be9c4 106 }
pmic 0:a0e9705be9c4 107
pmic 0:a0e9705be9c4 108 void EKF_RP::initialize_R()
pmic 0:a0e9705be9c4 109 {
pmic 5:676cbc33c81b 110 R << rho*var_gy(0)/Ts, 0.0f,
pmic 5:676cbc33c81b 111 0.0f, rho*var_gy(1)/Ts;
pmic 0:a0e9705be9c4 112 }
pmic 0:a0e9705be9c4 113
pmic 0:a0e9705be9c4 114 void EKF_RP::initialize_Q()
pmic 0:a0e9705be9c4 115 {
pmic 5:676cbc33c81b 116 Q << Ts*(var_fx(0) + s1*s1*s2*s2*var_fx(1)/(c2*c2)), Ts*c1*s1*s2*var_fx(1)/c2, 0.0f, 0.0f, 0.0f, 0.0f,
pmic 5:676cbc33c81b 117 Ts*c1*s1*s2*var_fx(1)/c2, Ts*c1*c1*var_fx(1), 0.0f, 0.0f, 0.0f, 0.0f,
pmic 5:676cbc33c81b 118 0.0f, 0.0f, Ts*var_fx(2), 0.0f, 0.0f, 0.0f,
pmic 5:676cbc33c81b 119 0.0f, 0.0f, 0.0f, Ts*var_fx(3), 0.0f, 0.0f,
pmic 5:676cbc33c81b 120 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(4), 0.0f,
pmic 5:676cbc33c81b 121 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(5);
pmic 0:a0e9705be9c4 122 }
pmic 0:a0e9705be9c4 123
pmic 4:e50e18eac72b 124 void EKF_RP::calc_Q()
pmic 0:a0e9705be9c4 125 {
pmic 4:e50e18eac72b 126 Q(0,0) = Ts*(var_fx(0) + s1*s1*s2*s2*var_fx(1)/(c2*c2));
pmic 0:a0e9705be9c4 127 Q(0,1) = Ts*c1*s1*s2*var_fx(1)/c2;
pmic 0:a0e9705be9c4 128 Q(1,0) = Q(0,1);
pmic 0:a0e9705be9c4 129 Q(1,1) = Ts*c1*c1*var_fx(1);
pmic 0:a0e9705be9c4 130 }
pmic 0:a0e9705be9c4 131
pmic 0:a0e9705be9c4 132 Matrix <float, 6, 1> EKF_RP::fxd()
pmic 0:a0e9705be9c4 133 {
pmic 0:a0e9705be9c4 134 Matrix <float, 6, 1> retval;
pmic 0:a0e9705be9c4 135 retval << x(0) + Ts*(u(0) - x(2) + (s1*s2*(u(1) - x(3)))/c2),
pmic 0:a0e9705be9c4 136 x(1) + Ts*c1*(u(1) - x(3)),
pmic 0:a0e9705be9c4 137 x(2),
pmic 0:a0e9705be9c4 138 x(3),
pmic 0:a0e9705be9c4 139 x(4) + Ts*(g*s2 - kv*x(4)),
pmic 0:a0e9705be9c4 140 x(5) - Ts*(kv*x(5) + c2*g*s1);
pmic 0:a0e9705be9c4 141 return retval;
pmic 0:a0e9705be9c4 142 }
pmic 0:a0e9705be9c4 143
pmic 0:a0e9705be9c4 144 Matrix <float, 2, 1> EKF_RP::gy()
pmic 0:a0e9705be9c4 145 {
pmic 0:a0e9705be9c4 146 Matrix <float, 2, 1> retval;
pmic 0:a0e9705be9c4 147 retval << -kv*x(4),
pmic 0:a0e9705be9c4 148 -kv*x(5);
pmic 0:a0e9705be9c4 149 return retval;
pmic 0:a0e9705be9c4 150 }
pmic 0:a0e9705be9c4 151