From 3bfc4ed5174c60de7eb98efbbf3c7729fcaa231e Mon Sep 17 00:00:00 2001 From: Anton Babushkin Date: Thu, 20 Jun 2013 11:30:10 +0400 Subject: Att rate PID fix --- src/modules/multirotor_att_control/multirotor_rate_control.c | 9 +++++---- src/modules/systemlib/pid/pid.c | 12 ++++++++---- src/modules/systemlib/pid/pid.h | 5 ++++- 3 files changed, 17 insertions(+), 9 deletions(-) diff --git a/src/modules/multirotor_att_control/multirotor_rate_control.c b/src/modules/multirotor_att_control/multirotor_rate_control.c index a0266e1b3..8f26a2014 100644 --- a/src/modules/multirotor_att_control/multirotor_rate_control.c +++ b/src/modules/multirotor_att_control/multirotor_rate_control.c @@ -179,6 +179,7 @@ void multirotor_control_rates(const struct vehicle_rates_setpoint_s *rate_sp, static bool initialized = false; + float diff_filter_factor = 1.0f; /* initialize the pid controllers when the function is called for the first time */ if (initialized == false) { @@ -186,8 +187,8 @@ void multirotor_control_rates(const struct vehicle_rates_setpoint_s *rate_sp, parameters_update(&h, &p); initialized = true; - pid_init(&pitch_rate_controller, p.attrate_p, p.attrate_i, p.attrate_d, 1.0f, 1.0f, 0.2f, PID_MODE_DERIVATIV_SET); - pid_init(&roll_rate_controller, p.attrate_p, p.attrate_i, p.attrate_d, 1.0f, 1.0f, 0.2f, PID_MODE_DERIVATIV_SET); + pid_init(&pitch_rate_controller, p.attrate_p, p.attrate_i, p.attrate_d, 1.0f, 1.0f, diff_filter_factor, PID_MODE_DERIVATIV_CALC_NO_SP); + pid_init(&roll_rate_controller, p.attrate_p, p.attrate_i, p.attrate_d, 1.0f, 1.0f, diff_filter_factor, PID_MODE_DERIVATIV_CALC_NO_SP); } @@ -195,8 +196,8 @@ void multirotor_control_rates(const struct vehicle_rates_setpoint_s *rate_sp, if (motor_skip_counter % 2500 == 0) { /* update parameters from storage */ parameters_update(&h, &p); - pid_set_parameters(&pitch_rate_controller, p.attrate_p, p.attrate_i, p.attrate_d, 1.0f, 1.0f, 0.2f); - pid_set_parameters(&roll_rate_controller, p.attrate_p, p.attrate_i, p.attrate_d, 1.0f, 1.0f, 0.2f); + pid_set_parameters(&pitch_rate_controller, p.attrate_p, p.attrate_i, p.attrate_d, 1.0f, 1.0f, diff_filter_factor); + pid_set_parameters(&roll_rate_controller, p.attrate_p, p.attrate_i, p.attrate_d, 1.0f, 1.0f, diff_filter_factor); } /* reset integral if on ground */ diff --git a/src/modules/systemlib/pid/pid.c b/src/modules/systemlib/pid/pid.c index 3685b2aeb..ada364e37 100644 --- a/src/modules/systemlib/pid/pid.c +++ b/src/modules/systemlib/pid/pid.c @@ -144,15 +144,19 @@ __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, flo // Calculated current error value float error = pid->sp - val; - - float error_filtered = pid->diff_filter_factor*error + (1.0f-pid->diff_filter_factor)*pid->error_previous_filtered; + float error_filtered; // Calculate or measured current error derivative if (pid->mode == PID_MODE_DERIVATIV_CALC) { -// d = (error_filtered - pid->error_previous_filtered) / dt; - d = error_filtered - pid->error_previous_filtered ; + error_filtered = pid->error_previous_filtered + (error - pid->error_previous_filtered) * pid->diff_filter_factor; + d = (error_filtered - pid->error_previous_filtered) / fmaxf(dt, 0.003f); // fail-safe for too low dt + pid->error_previous_filtered = error_filtered; + } else if (pid->mode == PID_MODE_DERIVATIV_CALC_NO_SP) { + + error_filtered = pid->error_previous_filtered + (val - pid->error_previous_filtered) * pid->diff_filter_factor; + d = (error_filtered - pid->error_previous_filtered) / fmaxf(dt, 0.003f); // fail-safe for too low dt pid->error_previous_filtered = error_filtered; } else if (pid->mode == PID_MODE_DERIVATIV_SET) { d = -val_dot; diff --git a/src/modules/systemlib/pid/pid.h b/src/modules/systemlib/pid/pid.h index e3d9038cd..eb9df96cc 100644 --- a/src/modules/systemlib/pid/pid.h +++ b/src/modules/systemlib/pid/pid.h @@ -47,8 +47,11 @@ /* PID_MODE_DERIVATIV_CALC calculates discrete derivative from previous error * val_dot in pid_calculate() will be ignored */ #define PID_MODE_DERIVATIV_CALC 0 +/* PID_MODE_DERIVATIV_CALC_NO_SP calculates discrete derivative from previous value, setpoint derivative is ignored + * val_dot in pid_calculate() will be ignored */ +#define PID_MODE_DERIVATIV_CALC_NO_SP 1 /* Use PID_MODE_DERIVATIV_SET if you have the derivative already (Gyros, Kalman) */ -#define PID_MODE_DERIVATIV_SET 1 +#define PID_MODE_DERIVATIV_SET 2 // Use PID_MODE_DERIVATIV_NONE for a PI controller (vs PID) #define PID_MODE_DERIVATIV_NONE 9 -- cgit v1.2.3