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Remove setpoint-change from error when calculating derivative in pid controller (#4737)

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Co-authored-by: Mathias Pihl <mapih@frode-laursen.com>
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Mathias Pihl 2023-12-13 00:50:55 +01:00 committed by GitHub
parent 8789925fe8
commit 69026f7599
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2 changed files with 10 additions and 4 deletions
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11
esphome/components/pid/pid_controller.cpp
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@ -16,7 +16,7 @@ float PIDController::update(float setpoint, float process_value) {
calculate_proportional_term_(); calculate_proportional_term_();
calculate_integral_term_(); calculate_integral_term_();
calculate_derivative_term_(); calculate_derivative_term_(setpoint);
// u(t) := p(t) + i(t) + d(t) // u(t) := p(t) + i(t) + d(t)
float output = proportional_term_ + integral_term_ + derivative_term_; float output = proportional_term_ + integral_term_ + derivative_term_;
@ -69,13 +69,18 @@ void PIDController::calculate_integral_term_() {
integral_term_ = accumulated_integral_; integral_term_ = accumulated_integral_;
} }
void PIDController::calculate_derivative_term_() { void PIDController::calculate_derivative_term_(float setpoint) {
// derivative_term_ // derivative_term_
// d(t) := K_d * de(t)/dt // d(t) := K_d * de(t)/dt
float derivative = 0.0f; float derivative = 0.0f;
if (dt_ != 0.0f) if (dt_ != 0.0f) {
// remove changes to setpoint from error
if (!std::isnan(previous_setpoint_) && previous_setpoint_ != setpoint)
previous_error_ -= previous_setpoint_ - setpoint;
derivative = (error_ - previous_error_) / dt_; derivative = (error_ - previous_error_) / dt_;
}
previous_error_ = error_; previous_error_ = error_;
previous_setpoint_ = setpoint;
// smooth the derivative samples // smooth the derivative samples
derivative = weighted_average_(derivative_list_, derivative, derivative_samples_); derivative = weighted_average_(derivative_list_, derivative, derivative_samples_);

3
esphome/components/pid/pid_controller.h
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@ -49,12 +49,13 @@ struct PIDController {
void calculate_proportional_term_(); void calculate_proportional_term_();
void calculate_integral_term_(); void calculate_integral_term_();
void calculate_derivative_term_(); void calculate_derivative_term_(float setpoint);
float weighted_average_(std::deque<float> &list, float new_value, int samples); float weighted_average_(std::deque<float> &list, float new_value, int samples);
float calculate_relative_time_(); float calculate_relative_time_();
/// Error from previous update used for derivative term /// Error from previous update used for derivative term
float previous_error_ = 0; float previous_error_ = 0;
float previous_setpoint_ = NAN;
/// Accumulated integral value /// Accumulated integral value
float accumulated_integral_ = 0; float accumulated_integral_ = 0;
uint32_t last_time_ = 0; uint32_t last_time_ = 0;