mirror of
https://github.com/betaflight/betaflight.git
synced 2025-07-25 09:16:07 +03:00
319 lines
13 KiB
C
319 lines
13 KiB
C
/*
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* This file is part of Cleanflight.
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*
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* Cleanflight is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Cleanflight is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Cleanflight. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdbool.h>
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#include <stdint.h>
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#include <math.h>
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#include <platform.h>
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#include "build/build_config.h"
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#include "build/debug.h"
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#include "common/axis.h"
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#include "common/maths.h"
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#include "common/filter.h"
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#include "fc/rc_controls.h"
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#include "fc/runtime_config.h"
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#include "flight/pid.h"
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#include "flight/imu.h"
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#include "flight/navigation.h"
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#include "flight/gtune.h"
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#include "sensors/gyro.h"
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#include "sensors/acceleration.h"
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extern float rcInput[3];
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extern float setpointRate[3];
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uint32_t targetPidLooptime;
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static bool pidStabilisationEnabled;
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float axisPIDf[3];
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// PIDweight is a scale factor for PIDs which is derived from the throttle and TPA setting, and 100 = 100% scale means no PID reduction
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uint8_t PIDweight[3];
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#ifdef BLACKBOX
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int32_t axisPID_P[3], axisPID_I[3], axisPID_D[3];
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#endif
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static float errorGyroIf[3];
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void pidSetTargetLooptime(uint32_t pidLooptime)
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{
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targetPidLooptime = pidLooptime;
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}
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void pidResetErrorGyroState(void)
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{
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for (int axis = 0; axis < 3; axis++) {
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errorGyroIf[axis] = 0.0f;
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}
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}
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void pidStabilisationState(pidStabilisationState_e pidControllerState)
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{
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pidStabilisationEnabled = (pidControllerState == PID_STABILISATION_ON) ? true : false;
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}
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const angle_index_t rcAliasToAngleIndexMap[] = { AI_ROLL, AI_PITCH };
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static filterApplyFnPtr dtermNotchFilterApplyFn;
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static void *dtermFilterNotch[2];
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static filterApplyFnPtr dtermLpfApplyFn;
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static void *dtermFilterLpf[2];
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static filterApplyFnPtr ptermYawFilterApplyFn;
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static void *ptermYawFilter;
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void pidInitFilters(const pidProfile_t *pidProfile)
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{
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static biquadFilter_t biquadFilterNotch[2];
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static pt1Filter_t pt1Filter[2];
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static biquadFilter_t biquadFilter[2];
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static firFilterDenoise_t denoisingFilter[2];
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static pt1Filter_t pt1FilterYaw;
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BUILD_BUG_ON(FD_YAW != 2); // only setting up Dterm filters on roll and pitch axes, so ensure yaw axis is 2
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const float dT = (float)targetPidLooptime * 0.000001f;
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if (pidProfile->dterm_notch_hz == 0) {
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dtermNotchFilterApplyFn = nullFilterApply;
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} else {
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dtermNotchFilterApplyFn = (filterApplyFnPtr)biquadFilterApply;
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const float notchQ = filterGetNotchQ(pidProfile->dterm_notch_hz, pidProfile->dterm_notch_cutoff);
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for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
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dtermFilterNotch[axis] = &biquadFilterNotch[axis];
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biquadFilterInit(dtermFilterNotch[axis], pidProfile->dterm_notch_hz, targetPidLooptime, notchQ, FILTER_NOTCH);
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}
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}
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if (pidProfile->dterm_lpf_hz == 0) {
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dtermLpfApplyFn = nullFilterApply;
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} else {
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switch (pidProfile->dterm_filter_type) {
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default:
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dtermLpfApplyFn = nullFilterApply;
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break;
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case FILTER_PT1:
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dtermLpfApplyFn = (filterApplyFnPtr)pt1FilterApply;
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for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
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dtermFilterLpf[axis] = &pt1Filter[axis];
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pt1FilterInit(dtermFilterLpf[axis], pidProfile->dterm_lpf_hz, dT);
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}
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break;
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case FILTER_BIQUAD:
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dtermLpfApplyFn = (filterApplyFnPtr)biquadFilterApply;
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for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
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dtermFilterLpf[axis] = &biquadFilter[axis];
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biquadFilterInitLPF(dtermFilterLpf[axis], pidProfile->dterm_lpf_hz, targetPidLooptime);
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}
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break;
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case FILTER_FIR:
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dtermLpfApplyFn = (filterApplyFnPtr)firFilterDenoiseUpdate;
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for (int axis = FD_ROLL; axis <= FD_PITCH; axis++) {
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dtermFilterLpf[axis] = &denoisingFilter[axis];
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firFilterDenoiseInit(dtermFilterLpf[axis], pidProfile->dterm_lpf_hz, targetPidLooptime);
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}
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break;
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}
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}
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if (pidProfile->yaw_lpf_hz == 0) {
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ptermYawFilterApplyFn = nullFilterApply;
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} else {
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ptermYawFilterApplyFn = (filterApplyFnPtr)pt1FilterApply;
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ptermYawFilter = &pt1FilterYaw;
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pt1FilterInit(ptermYawFilter, pidProfile->yaw_lpf_hz, dT);
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}
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}
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// Betaflight pid controller, which will be maintained in the future with additional features specialised for current (mini) multirotor usage.
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// Based on 2DOF reference design (matlab)
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void pidController(const pidProfile_t *pidProfile, uint16_t max_angle_inclination,
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const rollAndPitchTrims_t *angleTrim, uint16_t midrc)
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{
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static float lastRateError[2];
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static float Kp[3], Ki[3], Kd[3], c[3];
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static float rollPitchMaxVelocity, yawMaxVelocity;
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static float previousSetpoint[3], relaxFactor[3];
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static float dT;
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if (!dT) {
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dT = (float)targetPidLooptime * 0.000001f;
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}
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float horizonLevelStrength = 1;
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if (FLIGHT_MODE(HORIZON_MODE)) {
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// Figure out the raw stick positions
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const int32_t stickPosAil = ABS(getRcStickDeflection(FD_ROLL, midrc));
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const int32_t stickPosEle = ABS(getRcStickDeflection(FD_PITCH, midrc));
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const int32_t mostDeflectedPos = MAX(stickPosAil, stickPosEle);
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// Progressively turn off the horizon self level strength as the stick is banged over
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horizonLevelStrength = (float)(500 - mostDeflectedPos) / 500; // 1 at centre stick, 0 = max stick deflection
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if(pidProfile->D8[PIDLEVEL] == 0){
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horizonLevelStrength = 0;
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} else {
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horizonLevelStrength = constrainf(((horizonLevelStrength - 1) * (100 / pidProfile->D8[PIDLEVEL])) + 1, 0, 1);
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}
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}
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// Yet Highly experimental and under test and development
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// Throttle coupled to Igain like inverted TPA // 50hz calculation (should cover all rx protocols)
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static float kiThrottleGain = 1.0f;
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if (pidProfile->itermThrottleGain) {
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const uint16_t maxLoopCount = 20000 / targetPidLooptime;
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const float throttleItermGain = (float)pidProfile->itermThrottleGain * 0.001f;
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static int16_t previousThrottle;
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static uint16_t loopIncrement;
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if (loopIncrement >= maxLoopCount) {
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kiThrottleGain = 1.0f + constrainf((float)(ABS(rcCommand[THROTTLE] - previousThrottle)) * throttleItermGain, 0.0f, 5.0f); // Limit to factor 5
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previousThrottle = rcCommand[THROTTLE];
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loopIncrement = 0;
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} else {
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loopIncrement++;
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}
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}
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// ----------PID controller----------
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const float tpaFactor = PIDweight[0] / 100.0f; // tpa is now float
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for (int axis = FD_ROLL; axis <= FD_YAW; axis++) {
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static uint8_t configP[3], configI[3], configD[3];
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// Prevent unnecessary computing and check for changed PIDs. No need for individual checks. Only pids is fine for now
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// Prepare all parameters for PID controller
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if ((pidProfile->P8[axis] != configP[axis]) || (pidProfile->I8[axis] != configI[axis]) || (pidProfile->D8[axis] != configD[axis])) {
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Kp[axis] = PTERM_SCALE * pidProfile->P8[axis];
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Ki[axis] = ITERM_SCALE * pidProfile->I8[axis];
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Kd[axis] = DTERM_SCALE * pidProfile->D8[axis];
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c[axis] = pidProfile->dtermSetpointWeight / 100.0f;
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relaxFactor[axis] = 1.0f - (pidProfile->setpointRelaxRatio / 100.0f);
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yawMaxVelocity = pidProfile->yawRateAccelLimit * 1000 * dT;
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rollPitchMaxVelocity = pidProfile->rateAccelLimit * 1000 * dT;
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configP[axis] = pidProfile->P8[axis];
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configI[axis] = pidProfile->I8[axis];
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configD[axis] = pidProfile->D8[axis];
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}
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// Limit abrupt yaw inputs / stops
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const float maxVelocity = (axis == FD_YAW) ? yawMaxVelocity : rollPitchMaxVelocity;
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if (maxVelocity) {
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const float currentVelocity = setpointRate[axis] - previousSetpoint[axis];
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if (ABS(currentVelocity) > maxVelocity) {
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setpointRate[axis] = (currentVelocity > 0) ? previousSetpoint[axis] + maxVelocity : previousSetpoint[axis] - maxVelocity;
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}
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previousSetpoint[axis] = setpointRate[axis];
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}
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// Yaw control is GYRO based, direct sticks control is applied to rate PID
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if ((FLIGHT_MODE(ANGLE_MODE) || FLIGHT_MODE(HORIZON_MODE)) && axis != YAW) {
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// calculate error angle and limit the angle to the max inclination
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#ifdef GPS
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const float errorAngle = (constrainf(pidProfile->levelSensitivity * rcCommand[axis] + GPS_angle[axis], -((int) max_angle_inclination),
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+max_angle_inclination) - attitude.raw[axis] + angleTrim->raw[axis]) / 10.0f; // 16 bits is ok here
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#else
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const float errorAngle = (constrainf(pidProfile->levelSensitivity * rcCommand[axis], -((int) max_angle_inclination),
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+max_angle_inclination) - attitude.raw[axis] + angleTrim->raw[axis]) / 10.0f; // 16 bits is ok here
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#endif
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if (FLIGHT_MODE(ANGLE_MODE)) {
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// ANGLE mode - control is angle based, so control loop is needed
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setpointRate[axis] = errorAngle * pidProfile->P8[PIDLEVEL] / 10.0f;
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} else {
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// HORIZON mode - direct sticks control is applied to rate PID
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// mix up angle error to desired AngleRate to add a little auto-level feel
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setpointRate[axis] = setpointRate[axis] + (errorAngle * pidProfile->I8[PIDLEVEL] * horizonLevelStrength / 10.0f);
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}
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}
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const float PVRate = gyroADCf[axis]; // Process variable from gyro output in deg/sec
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// --------low-level gyro-based PID based on 2DOF PID controller. ----------
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// ---------- 2-DOF PID controller with optional filter on derivative term. b = 1 and only c can be tuned (amount derivative on measurement or error). ----------
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// -----calculate error rate
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const float errorRate = setpointRate[axis] - PVRate; // r - y
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// -----calculate P component and add Dynamic Part based on stick input
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float PTerm = Kp[axis] * errorRate * tpaFactor;
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// -----calculate I component
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// Reduce strong Iterm accumulation during higher stick inputs
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const float accumulationThreshold = (axis == FD_YAW) ? pidProfile->yawItermIgnoreRate : pidProfile->rollPitchItermIgnoreRate;
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const float setpointRateScaler = constrainf(1.0f - (ABS(setpointRate[axis]) / accumulationThreshold), 0.0f, 1.0f);
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const float itermScaler = setpointRateScaler * kiThrottleGain;
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float ITerm = errorGyroIf[axis];
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ITerm += Ki[axis] * errorRate * dT * itermScaler;;
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// limit maximum integrator value to prevent WindUp
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ITerm = constrainf(ITerm, -250.0f, 250.0f);
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errorGyroIf[axis] = ITerm;
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// -----calculate D component (Yaw D not yet supported)
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float DTerm = 0.0;
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if (axis != FD_YAW) {
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static float previousSetpoint[3];
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float dynC = c[axis];
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if (pidProfile->setpointRelaxRatio < 100) {
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dynC = c[axis];
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if (setpointRate[axis] > 0) {
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if ((setpointRate[axis] - previousSetpoint[axis]) < previousSetpoint[axis])
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dynC = dynC * powerf(rcInput[axis], 2) * relaxFactor[axis] + dynC * (1-relaxFactor[axis]);
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} else if (setpointRate[axis] < 0) {
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if ((setpointRate[axis] - previousSetpoint[axis]) > previousSetpoint[axis])
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dynC = dynC * powerf(rcInput[axis], 2) * relaxFactor[axis] + dynC * (1-relaxFactor[axis]);
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}
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}
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previousSetpoint[axis] = setpointRate[axis];
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const float rD = dynC * setpointRate[axis] - PVRate; // cr - y
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// Divide rate change by dT to get differential (ie dr/dt)
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const float delta = (rD - lastRateError[axis]) / dT;
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lastRateError[axis] = rD;
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DTerm = Kd[axis] * delta * tpaFactor;
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DEBUG_SET(DEBUG_DTERM_FILTER, axis, DTerm);
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// apply filters
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DTerm = dtermNotchFilterApplyFn(dtermFilterNotch[axis], DTerm);
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DTerm = dtermLpfApplyFn(dtermFilterLpf[axis], DTerm);
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} else {
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PTerm = ptermYawFilterApplyFn(ptermYawFilter, PTerm);
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}
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// -----calculate total PID output
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axisPIDf[axis] = PTerm + ITerm + DTerm;
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// Disable PID control at zero throttle
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if (!pidStabilisationEnabled) axisPIDf[axis] = 0;
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#ifdef GTUNE
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if (FLIGHT_MODE(GTUNE_MODE) && ARMING_FLAG(ARMED)) {
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calculate_Gtune(axis);
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}
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#endif
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#ifdef BLACKBOX
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axisPID_P[axis] = PTerm;
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axisPID_I[axis] = ITerm;
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axisPID_D[axis] = DTerm;
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#endif
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}
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}
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