Files
ODrive/Firmware/MotorControl/controller.cpp
2020-11-16 21:03:23 +01:00

347 lines
13 KiB
C++

#include "odrive_main.h"
#include <algorithm>
bool Controller::apply_config() {
config_.parent = this;
update_filter_gains();
return true;
}
void Controller::reset() {
pos_setpoint_ = 0.0f;
vel_setpoint_ = 0.0f;
vel_integrator_torque_ = 0.0f;
torque_setpoint_ = 0.0f;
}
void Controller::set_error(Error error) {
error_ |= error;
}
//--------------------------------
// Command Handling
//--------------------------------
void Controller::move_to_pos(float goal_point) {
axis_->trap_traj_.planTrapezoidal(goal_point, pos_setpoint_, vel_setpoint_,
axis_->trap_traj_.config_.vel_limit,
axis_->trap_traj_.config_.accel_limit,
axis_->trap_traj_.config_.decel_limit);
axis_->trap_traj_.t_ = 0.0f;
trajectory_done_ = false;
}
void Controller::move_incremental(float displacement, bool from_input_pos = true){
if(from_input_pos){
input_pos_ += displacement;
} else{
input_pos_ = pos_setpoint_ + displacement;
}
input_pos_updated();
}
void Controller::start_anticogging_calibration() {
// Ensure the cogging map was correctly allocated earlier and that the motor is capable of calibrating
if (axis_->error_ == Axis::ERROR_NONE) {
config_.anticogging.calib_anticogging = true;
}
}
/*
* This anti-cogging implementation iterates through each encoder position,
* waits for zero velocity & position error,
* then samples the current required to maintain that position.
*
* This holding current is added as a feedforward term in the control loop.
*/
bool Controller::anticogging_calibration(float pos_estimate, float vel_estimate) {
float pos_err = input_pos_ - pos_estimate;
if (std::abs(pos_err) <= config_.anticogging.calib_pos_threshold / (float)axis_->encoder_.config_.cpr &&
std::abs(vel_estimate) < config_.anticogging.calib_vel_threshold / (float)axis_->encoder_.config_.cpr) {
config_.anticogging.cogging_map[std::clamp<uint32_t>(config_.anticogging.index++, 0, 3600)] = vel_integrator_torque_;
}
if (config_.anticogging.index < 3600) {
config_.control_mode = CONTROL_MODE_POSITION_CONTROL;
input_pos_ = config_.anticogging.index * axis_->encoder_.getCoggingRatio();
input_vel_ = 0.0f;
input_torque_ = 0.0f;
input_pos_updated();
return false;
} else {
config_.anticogging.index = 0;
config_.control_mode = CONTROL_MODE_POSITION_CONTROL;
input_pos_ = 0.0f; // Send the motor home
input_vel_ = 0.0f;
input_torque_ = 0.0f;
input_pos_updated();
anticogging_valid_ = true;
config_.anticogging.calib_anticogging = false;
return true;
}
}
void Controller::update_filter_gains() {
float bandwidth = std::min(config_.input_filter_bandwidth, 0.25f * current_meas_hz);
input_filter_ki_ = 2.0f * bandwidth; // basic conversion to discrete time
input_filter_kp_ = 0.25f * (input_filter_ki_ * input_filter_ki_); // Critically damped
}
static float limitVel(const float vel_limit, const float vel_estimate, const float vel_gain, const float torque) {
float Tmax = (vel_limit - vel_estimate) * vel_gain;
float Tmin = (-vel_limit - vel_estimate) * vel_gain;
return std::clamp(torque, Tmin, Tmax);
}
bool Controller::update() {
std::optional<float> pos_estimate_linear = pos_estimate_linear_src_.present();
std::optional<float> pos_estimate_circular = pos_estimate_circular_src_.present();
std::optional<float> pos_wrap = pos_wrap_src_.present();
std::optional<float> vel_estimate = vel_estimate_src_.present();
std::optional<float> anticogging_pos_estimate = axis_->encoder_.pos_estimate_.present();
std::optional<float> anticogging_vel_estimate = axis_->encoder_.vel_estimate_.present();
if (config_.anticogging.calib_anticogging) {
if (!anticogging_pos_estimate.has_value() || !anticogging_vel_estimate.has_value()) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
// non-blocking
anticogging_calibration(*anticogging_pos_estimate, *anticogging_vel_estimate);
}
// TODO also enable circular deltas for 2nd order filter, etc.
if (config_.circular_setpoints) {
// Keep pos setpoint from drifting
input_pos_ = fmodf_pos(input_pos_, config_.circular_setpoint_range);
}
// Update inputs
switch (config_.input_mode) {
case INPUT_MODE_INACTIVE: {
// do nothing
} break;
case INPUT_MODE_PASSTHROUGH: {
pos_setpoint_ = input_pos_;
vel_setpoint_ = input_vel_;
torque_setpoint_ = input_torque_;
} break;
case INPUT_MODE_VEL_RAMP: {
float max_step_size = std::abs(current_meas_period * config_.vel_ramp_rate);
float full_step = input_vel_ - vel_setpoint_;
float step = std::clamp(full_step, -max_step_size, max_step_size);
vel_setpoint_ += step;
torque_setpoint_ = (step / current_meas_period) * config_.inertia;
} break;
case INPUT_MODE_TORQUE_RAMP: {
float max_step_size = std::abs(current_meas_period * config_.torque_ramp_rate);
float full_step = input_torque_ - torque_setpoint_;
float step = std::clamp(full_step, -max_step_size, max_step_size);
torque_setpoint_ += step;
} break;
case INPUT_MODE_POS_FILTER: {
// 2nd order pos tracking filter
float delta_pos = input_pos_ - pos_setpoint_; // Pos error
float delta_vel = input_vel_ - vel_setpoint_; // Vel error
float accel = input_filter_kp_*delta_pos + input_filter_ki_*delta_vel; // Feedback
torque_setpoint_ = accel * config_.inertia; // Accel
vel_setpoint_ += current_meas_period * accel; // delta vel
pos_setpoint_ += current_meas_period * vel_setpoint_; // Delta pos
} break;
case INPUT_MODE_MIRROR: {
if (config_.axis_to_mirror < AXIS_COUNT) {
std::optional<float> other_pos = axes[config_.axis_to_mirror].encoder_.pos_estimate_.present();
std::optional<float> other_vel = axes[config_.axis_to_mirror].encoder_.vel_estimate_.present();
if (!other_pos.has_value() || !other_vel.has_value()) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
pos_setpoint_ = *other_pos * config_.mirror_ratio;
vel_setpoint_ = *other_vel * config_.mirror_ratio;
} else {
set_error(ERROR_INVALID_MIRROR_AXIS);
return false;
}
} break;
// case INPUT_MODE_MIX_CHANNELS: {
// // NOT YET IMPLEMENTED
// } break;
case INPUT_MODE_TRAP_TRAJ: {
if(input_pos_updated_){
move_to_pos(input_pos_);
input_pos_updated_ = false;
}
// Avoid updating uninitialized trajectory
if (trajectory_done_)
break;
if (axis_->trap_traj_.t_ > axis_->trap_traj_.Tf_) {
// Drop into position control mode when done to avoid problems on loop counter delta overflow
config_.control_mode = CONTROL_MODE_POSITION_CONTROL;
pos_setpoint_ = input_pos_;
vel_setpoint_ = 0.0f;
torque_setpoint_ = 0.0f;
trajectory_done_ = true;
} else {
TrapezoidalTrajectory::Step_t traj_step = axis_->trap_traj_.eval(axis_->trap_traj_.t_);
pos_setpoint_ = traj_step.Y;
vel_setpoint_ = traj_step.Yd;
torque_setpoint_ = traj_step.Ydd * config_.inertia;
axis_->trap_traj_.t_ += current_meas_period;
}
anticogging_pos_estimate = pos_setpoint_; // FF the position setpoint instead of the pos_estimate
} break;
default: {
set_error(ERROR_INVALID_INPUT_MODE);
return false;
}
}
// Position control
// TODO Decide if we want to use encoder or pll position here
float gain_scheduling_multiplier = 1.0f;
float vel_des = vel_setpoint_;
if (config_.control_mode >= CONTROL_MODE_POSITION_CONTROL) {
float pos_err;
if (config_.circular_setpoints) {
if (!pos_estimate_circular.has_value() || !pos_wrap.has_value()) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
// Keep pos setpoint from drifting
pos_setpoint_ = fmodf_pos(pos_setpoint_, *pos_wrap);
// Circular delta
pos_err = pos_setpoint_ - *pos_estimate_circular;
pos_err = wrap_pm(pos_err, *pos_wrap);
} else {
if (!pos_estimate_linear.has_value()) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
pos_err = pos_setpoint_ - *pos_estimate_linear;
}
vel_des += config_.pos_gain * pos_err;
// V-shaped gain shedule based on position error
float abs_pos_err = std::abs(pos_err);
if (config_.enable_gain_scheduling && abs_pos_err <= config_.gain_scheduling_width) {
gain_scheduling_multiplier = abs_pos_err / config_.gain_scheduling_width;
}
}
// Velocity limiting
float vel_lim = config_.vel_limit;
if (config_.enable_vel_limit) {
vel_des = std::clamp(vel_des, -vel_lim, vel_lim);
}
// Check for overspeed fault (done in this module (controller) for cohesion with vel_lim)
if (config_.enable_overspeed_error) { // 0.0f to disable
if (!vel_estimate.has_value()) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
if (std::abs(*vel_estimate) > config_.vel_limit_tolerance * vel_lim) {
set_error(ERROR_OVERSPEED);
return false;
}
}
// TODO: Change to controller working in torque units
// Torque per amp gain scheduling (ACIM)
float vel_gain = config_.vel_gain;
float vel_integrator_gain = config_.vel_integrator_gain;
if (axis_->motor_.config_.motor_type == Motor::MOTOR_TYPE_ACIM) {
float effective_flux = axis_->acim_estimator_.rotor_flux_;
float minflux = axis_->motor_.config_.acim_gain_min_flux;
if (std::abs(effective_flux) < minflux)
effective_flux = std::copysignf(minflux, effective_flux);
vel_gain /= effective_flux;
vel_integrator_gain /= effective_flux;
// TODO: also scale the integral value which is also changing units.
// (or again just do control in torque units)
}
// Velocity control
float torque = torque_setpoint_;
// Anti-cogging is enabled after calibration
// We get the current position and apply a current feed-forward
// ensuring that we handle negative encoder positions properly (-1 == motor->encoder.encoder_cpr - 1)
if (anticogging_valid_ && config_.anticogging.anticogging_enabled) {
if (!anticogging_pos_estimate.has_value()) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
float anticogging_pos = *anticogging_pos_estimate / axis_->encoder_.getCoggingRatio();
torque += config_.anticogging.cogging_map[std::clamp(mod((int)anticogging_pos, 3600), 0, 3600)];
}
float v_err = 0.0f;
if (config_.control_mode >= CONTROL_MODE_VELOCITY_CONTROL) {
if (!vel_estimate.has_value()) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
v_err = vel_des - *vel_estimate;
torque += (vel_gain * gain_scheduling_multiplier) * v_err;
// Velocity integral action before limiting
torque += vel_integrator_torque_;
}
// Velocity limiting in current mode
if (config_.control_mode < CONTROL_MODE_VELOCITY_CONTROL && config_.enable_current_mode_vel_limit) {
if (!vel_estimate.has_value()) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
torque = limitVel(config_.vel_limit, *vel_estimate, vel_gain, torque);
}
// Torque limiting
bool limited = false;
float Tlim = axis_->motor_.max_available_torque();
if (torque > Tlim) {
limited = true;
torque = Tlim;
}
if (torque < -Tlim) {
limited = true;
torque = -Tlim;
}
// Velocity integrator (behaviour dependent on limiting)
if (config_.control_mode < CONTROL_MODE_VELOCITY_CONTROL) {
// reset integral if not in use
vel_integrator_torque_ = 0.0f;
} else {
if (limited) {
// TODO make decayfactor configurable
vel_integrator_torque_ *= 0.99f;
} else {
vel_integrator_torque_ += ((vel_integrator_gain * gain_scheduling_multiplier) * current_meas_period) * v_err;
}
}
torque_output_ = torque;
// TODO: this is inconsistent with the other errors which are sticky.
// However if we make ERROR_INVALID_ESTIMATE sticky then it will be
// confusing that a normal sequence of motor calibration + encoder
// calibration would leave the controller in an error state.
error_ &= ~ERROR_INVALID_ESTIMATE;
return true;
}