altb_pmic / Mbed 2 deprecated Test_ekf

Testing ekf implementation for Quadro_1.

Dependencies:   mbed Eigen

EKF_RP.cpp@18:f374ca9a3e75, 2019-10-28 (annotated)

Committer:
pmic
Date:
Mon Oct 28 11:31:48 2019 +0000
Revision:
18:f374ca9a3e75
Parent:
17:1d98928f7681
Child:
19:ccb6fc8bf872
Change initialization of P0 in EKF_RP and EKF_RPY.

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 0:a0e9705be9c4 16 reset();
pmic 0:a0e9705be9c4 17 }
pmic 0:a0e9705be9c4 18
pmic 0:a0e9705be9c4 19 EKF_RP::~EKF_RP() {}
pmic 0:a0e9705be9c4 20
pmic 0:a0e9705be9c4 21 void EKF_RP::reset()
pmic 0:a0e9705be9c4 22 {
pmic 0:a0e9705be9c4 23 u.setZero();
pmic 0:a0e9705be9c4 24 y.setZero();
pmic 0:a0e9705be9c4 25 x.setZero();
pmic 4:e50e18eac72b 26 update_angles();
pmic 4:e50e18eac72b 27 calc_F();
pmic 4:e50e18eac72b 28 calc_H();
pmic 0:a0e9705be9c4 29 initialize_Q();
pmic 0:a0e9705be9c4 30 initialize_R();
pmic 18:f374ca9a3e75 31 P = 1000000.0f * ( F * P * F.transpose() + Q );
pmic 0:a0e9705be9c4 32 K.setZero();
pmic 0:a0e9705be9c4 33 I.setIdentity();
pmic 13:2e03d9c03409 34 e.setZero();
pmic 0:a0e9705be9c4 35 }
pmic 0:a0e9705be9c4 36
pmic 4:e50e18eac72b 37 float EKF_RP::get_est_state(uint8_t i)
pmic 4:e50e18eac72b 38 {
pmic 7:bcbcc23983de 39 /* x = [ang; v; b_g] = [0: phi
pmic 7:bcbcc23983de 40 1: theta
pmic 7:bcbcc23983de 41 2: vx
pmic 7:bcbcc23983de 42 3: vy
pmic 7:bcbcc23983de 43 4: b_gx
pmic 7:bcbcc23983de 44 5: b_gy] */
pmic 4:e50e18eac72b 45 return x(i);
pmic 4:e50e18eac72b 46 }
pmic 4:e50e18eac72b 47
pmic 0:a0e9705be9c4 48 void EKF_RP::update(float gyro_x, float gyro_y, float accel_x, float accel_y)
pmic 0:a0e9705be9c4 49 {
pmic 4:e50e18eac72b 50 u << gyro_x, gyro_y;
pmic 4:e50e18eac72b 51 y << accel_x, accel_y;
pmic 4:e50e18eac72b 52 update_angles();
pmic 0:a0e9705be9c4 53
pmic 4:e50e18eac72b 54 calc_F();
pmic 5:676cbc33c81b 55 // calc_H(); /* H remains constant */
pmic 4:e50e18eac72b 56 calc_Q();
pmic 0:a0e9705be9c4 57
pmic 4:e50e18eac72b 58 x = fxd();
pmic 5:676cbc33c81b 59 P = F * P * F.transpose() + Q;
pmic 13:2e03d9c03409 60 e = y - gy();
pmic 0:a0e9705be9c4 61
pmic 17:1d98928f7681 62 /* inversion faster 184 mus < 207 mus recursion */
pmic 17:1d98928f7681 63 K = P * H.transpose() * ( H * P * H.transpose() + R ).inverse();
pmic 17:1d98928f7681 64 x = x + K * e;
pmic 17:1d98928f7681 65 P = (I - K * H) * P;
pmic 15:53485bd1ff28 66
pmic 13:2e03d9c03409 67 /* only valid if R is diagonal (uncorrelated noise) */
pmic 17:1d98928f7681 68 /*
pmic 16:c39e084f05ed 69 for(uint8_t i = 0; i < 2; i++) {
pmic 16:c39e084f05ed 70 K.col(i) = ( P * (H.row(i)).transpose() ) / ( H.row(i) * P * (H.row(i)).transpose() + R(i,i) );
pmic 16:c39e084f05ed 71 x = x + K.col(i) * e(i);
pmic 16:c39e084f05ed 72 P = (I - K.col(i)*H.row(i)) * P;
pmic 17:1d98928f7681 73 }
pmic 17:1d98928f7681 74 */
pmic 0:a0e9705be9c4 75 }
pmic 0:a0e9705be9c4 76
pmic 0:a0e9705be9c4 77 void EKF_RP::update_angles()
pmic 0:a0e9705be9c4 78 {
pmic 5:676cbc33c81b 79 s1 = sinf(x(0));
pmic 5:676cbc33c81b 80 c1 = cosf(x(0));
pmic 5:676cbc33c81b 81 s2 = sinf(x(1));
pmic 5:676cbc33c81b 82 c2 = cosf(x(1));
pmic 0:a0e9705be9c4 83 }
pmic 0:a0e9705be9c4 84
pmic 4:e50e18eac72b 85 void EKF_RP::calc_F()
pmic 0:a0e9705be9c4 86 {
pmic 7:bcbcc23983de 87 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 88 -Ts*s1*(u(1) - x(3)), 1.0f, 0.0f, -Ts*c1, 0.0f, 0.0f,
pmic 7:bcbcc23983de 89 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
pmic 7:bcbcc23983de 90 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
pmic 7:bcbcc23983de 91 0.0f, Ts*c2*g, 0.0f, 0.0f, 1.0f - Ts*kv, 0.0f,
pmic 7:bcbcc23983de 92 -Ts*c1*c2*g, Ts*g*s1*s2, 0.0f, 0.0f, 0.0f, 1.0f - Ts*kv;
pmic 0:a0e9705be9c4 93 }
pmic 0:a0e9705be9c4 94
pmic 4:e50e18eac72b 95 void EKF_RP::calc_H()
pmic 0:a0e9705be9c4 96 {
pmic 5:676cbc33c81b 97 H << 0.0f, 0.0f, 0.0f, 0.0f, -kv, 0.0f,
pmic 5:676cbc33c81b 98 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -kv;
pmic 0:a0e9705be9c4 99 }
pmic 0:a0e9705be9c4 100
pmic 0:a0e9705be9c4 101 void EKF_RP::initialize_R()
pmic 0:a0e9705be9c4 102 {
pmic 5:676cbc33c81b 103 R << rho*var_gy(0)/Ts, 0.0f,
pmic 5:676cbc33c81b 104 0.0f, rho*var_gy(1)/Ts;
pmic 0:a0e9705be9c4 105 }
pmic 0:a0e9705be9c4 106
pmic 0:a0e9705be9c4 107 void EKF_RP::initialize_Q()
pmic 0:a0e9705be9c4 108 {
pmic 5:676cbc33c81b 109 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 110 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 111 0.0f, 0.0f, Ts*var_fx(2), 0.0f, 0.0f, 0.0f,
pmic 5:676cbc33c81b 112 0.0f, 0.0f, 0.0f, Ts*var_fx(3), 0.0f, 0.0f,
pmic 5:676cbc33c81b 113 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(4), 0.0f,
pmic 5:676cbc33c81b 114 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(5);
pmic 0:a0e9705be9c4 115 }
pmic 0:a0e9705be9c4 116
pmic 4:e50e18eac72b 117 void EKF_RP::calc_Q()
pmic 0:a0e9705be9c4 118 {
pmic 4:e50e18eac72b 119 Q(0,0) = Ts*(var_fx(0) + s1*s1*s2*s2*var_fx(1)/(c2*c2));
pmic 0:a0e9705be9c4 120 Q(0,1) = Ts*c1*s1*s2*var_fx(1)/c2;
pmic 0:a0e9705be9c4 121 Q(1,0) = Q(0,1);
pmic 0:a0e9705be9c4 122 Q(1,1) = Ts*c1*c1*var_fx(1);
pmic 0:a0e9705be9c4 123 }
pmic 0:a0e9705be9c4 124
pmic 0:a0e9705be9c4 125 Matrix <float, 6, 1> EKF_RP::fxd()
pmic 0:a0e9705be9c4 126 {
pmic 0:a0e9705be9c4 127 Matrix <float, 6, 1> retval;
pmic 0:a0e9705be9c4 128 retval << x(0) + Ts*(u(0) - x(2) + (s1*s2*(u(1) - x(3)))/c2),
pmic 0:a0e9705be9c4 129 x(1) + Ts*c1*(u(1) - x(3)),
pmic 0:a0e9705be9c4 130 x(2),
pmic 0:a0e9705be9c4 131 x(3),
pmic 0:a0e9705be9c4 132 x(4) + Ts*(g*s2 - kv*x(4)),
pmic 0:a0e9705be9c4 133 x(5) - Ts*(kv*x(5) + c2*g*s1);
pmic 0:a0e9705be9c4 134 return retval;
pmic 0:a0e9705be9c4 135 }
pmic 0:a0e9705be9c4 136
pmic 0:a0e9705be9c4 137 Matrix <float, 2, 1> EKF_RP::gy()
pmic 0:a0e9705be9c4 138 {
pmic 0:a0e9705be9c4 139 Matrix <float, 2, 1> retval;
pmic 0:a0e9705be9c4 140 retval << -kv*x(4),
pmic 0:a0e9705be9c4 141 -kv*x(5);
pmic 0:a0e9705be9c4 142 return retval;
pmic 0:a0e9705be9c4 143 }
pmic 0:a0e9705be9c4 144