1.select_encoder(size_t encoder_num).
这是控制器类(Controller)的函数,用于选择一个编码器作为该控制器的控制目标(如位置闭环控制时的位置反馈来源)。
bool Controller::select_encoder(size_t encoder_num) {
if (encoder_num < AXIS_COUNT) { //ODrive 固件通常支持多个轴(默认是2轴)
Axis* ax = axes[encoder_num];
pos_estimate_circular_src_ = &ax->encoder_.pos_circular_;
pos_wrap_src_ = &config_.circular_setpoint_range;
pos_estimate_linear_src_ = &ax->encoder_.pos_estimate_;
pos_estimate_valid_src_ = &ax->encoder_.pos_estimate_valid_;
vel_estimate_src_ = &ax->encoder_.vel_estimate_;
vel_estimate_valid_src_ = &ax->encoder_.vel_estimate_valid_;
return true;
} else {
return set_error(Controller::ERROR_INVALID_LOAD_ENCODER), false;
}
}
2.move_to_pos(float goal_point)
这个函数会使用梯形速度轨迹(Trapezoidal Trajectory)规划器,从当前位置移动到目标点 goal_point,并设置状态让控制器开始执行轨迹。
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;
}
3.move_incremental(float displacement, bool from_input_pos = true)
这个函数的作用是:相对于当前位置或当前设定值 pos_setpoint_,增量移动一个 displacement 距离;然后调用 input_pos_updated(),让控制器根据新的目标位置,开始执行新的轨迹或控制过程。
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();
}
4.anticogging_calibration(float pos_estimate, float vel_estimate)
这段代码是 ODrive 固件中的一个关键函数,用于抗齿槽效应(Anti-Cogging)校准,是高级电机控制中常用的补偿机制之一。抗齿槽效应(Anti-Cogging)是在电机静止或低速时,转子有细微卡滞,会导致运动不平滑,特别是在低速精密控制时很明显。
bool Controller::anticogging_calibration(float pos_estimate, float vel_estimate) {
float pos_err = input_pos_ - pos_estimate; //计算当前电机位置和设定位置之间的误差。希望它越接近 0 越好,表示电机已经稳定在期望位置。
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) {
//把当前位置所需的积分电流(即维持当前位置的扭矩)保存到 `cogging_map` 中,每执行一次这个函数,就测量一个点(`index` 代表当前点),`std::clamp` 防止越界(限制 index 在 0~3600 之间)
config_.anticogging.cogging_map[std::clamp<uint32_t>(config_.anticogging.index++, 0, 3600)] = vel_integrator_torque_;
}
if (config_.anticogging.index < 3600) {
//接下来设置下一个采样点,让电机移动到新的位置点继续采样:
config_.control_mode = CONTROL_MODE_POSITION_CONTROL;
input_pos_ = config_.anticogging.index * axis_->encoder_.getCoggingRatio();
//清空速度、力矩输入(表示只靠位置控制)
input_vel_ = 0.0f;
input_torque_ = 0.0f;
input_pos_updated();
return false;
} else {
//当所有点采样完毕:重置 index,把电机回零(归位),标记 `anticogging_valid_ = true` 表示数据可用,关闭校准模式标志.
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;
}
}
5.update_filter_gains()
update_filter_gains():更新输入滤波器的参数(带宽 → PID 系数),根据设定的带宽更新输入滤波器的 kp 和 ki 系数,以便输入信号平滑处理。
void Controller::update_filter_gains() {
//设定一个最大允许的滤波带宽,不能超过采样率的四分之一(Nyquist 准则的变种),current_meas_hz 是当前电流采样频率(控制回路频率,单位 Hz),input_filter_bandwidth 是配置中允许的最大滤波带宽
float bandwidth = std::min(config_.input_filter_bandwidth, 0.25f * current_meas_hz);
input_filter_ki_ = 2.0f * bandwidth; // basic conversion to discrete time //离散时间下的积分增益:假设使用一阶低通滤波器设计形式,2×带宽是常用近似
input_filter_kp_ = 0.25f * (input_filter_ki_ * input_filter_ki_); // 等价于设置滤波器为无振荡、快速响应的平稳系统
}
6.limitVel()
这是一个 速度限制函数,用于限制速度相关的扭矩指令大小,防止速度过冲或抖动。
static float limitVel(const float vel_limit, const float vel_estimate, const float vel_gain, const float torque) {
//动态计算的扭矩上下限:当 vel_estimate 靠近 vel_limit 时,Tmax 减小,防止继续加速,当速度超限时,Tmax 甚至为负,形成刹车力矩.
float Tmax = (vel_limit - vel_estimate) * vel_gain;
float Tmin = (-vel_limit - vel_estimate) * vel_gain;
return std::clamp(torque, Tmin, Tmax); //把输入 torque 限制在 Tmin ~ Tmax 范围内
}
7.update(float* torque_setpoint_output)
这是 ODrive 0.5.1 中 Controller::update() 的完整实现,是控制核心逻辑的心脏部分,主要完成从输入指令 → 内部处理 → 生成最终力矩指令(torque setpoint)的全过程。
bool Controller::update(float* torque_setpoint_output) {
//获取估计值来源:先检查 encoder 提供的位置/速度估计是否有效,如果有效则用对应的估计源(指针).
float* pos_estimate_linear = (pos_estimate_valid_src_ && *pos_estimate_valid_src_)
? pos_estimate_linear_src_ : nullptr;
float* pos_estimate_circular = (pos_estimate_valid_src_ && *pos_estimate_valid_src_)
? pos_estimate_circular_src_ : nullptr;
float* vel_estimate_src = (vel_estimate_valid_src_ && *vel_estimate_valid_src_)
? vel_estimate_src_ : nullptr;
// Anticogging 校准(如果启用)
float anticogging_pos = axis_->encoder_.pos_estimate_ / axis_->encoder_.getCoggingRatio();
if (config_.anticogging.calib_anticogging) {
if (!axis_->encoder_.pos_estimate_valid_ || !axis_->encoder_.vel_estimate_valid_) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
// non-blocking
anticogging_calibration(axis_->encoder_.pos_estimate_, axis_->encoder_.vel_estimate_);
}
// 使 input_pos_ 保持在 0~360(或指定范围)以内,避免角度漂移
if (config_.circular_setpoints) {
// Keep pos setpoint from drifting
input_pos_ = fmodf_pos(input_pos_, config_.circular_setpoint_range);
}
// 处理不同的输入模式
switch (config_.input_mode) {
case INPUT_MODE_INACTIVE: { //不做控制
// do nothing
} break;
case INPUT_MODE_PASSTHROUGH: { //直接传入输入值作为目标
pos_setpoint_ = input_pos_;
vel_setpoint_ = input_vel_;
torque_setpoint_ = input_torque_;
} break;
case INPUT_MODE_VEL_RAMP: { //限速变速模式,限制速度的变化率
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: { //限速变扭模式,限制扭矩变化率
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: { //二阶滤波器平滑输入位置
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: { //镜像另一个轴的状态
if (config_.axis_to_mirror < AXIS_COUNT) {
pos_setpoint_ = axes[config_.axis_to_mirror]->encoder_.pos_estimate_ * config_.mirror_ratio;
vel_setpoint_ = axes[config_.axis_to_mirror]->encoder_.vel_estimate_ * config_.mirror_ratio;
} else {
set_error(ERROR_INVALID_MIRROR_AXIS);
return false;
}
} break;
case INPUT_MODE_TRAP_TRAJ: { //梯形轨迹规划控制(加减速规划)
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 = 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) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
// Keep pos setpoint from drifting
pos_setpoint_ = fmodf_pos(pos_setpoint_, *pos_wrap_src_);
// Circular delta
pos_err = pos_setpoint_ - *pos_estimate_circular;
pos_err = wrap_pm(pos_err, 0.5f * *pos_wrap_src_);
} else {
if(!pos_estimate_linear) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
pos_err = pos_setpoint_ - *pos_estimate_linear;
}
vel_des += config_.pos_gain * pos_err; //位置误差转换成期望速度(PD 控制思想)
// 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;
}
}
// 限速 & 超速检测
float vel_lim = config_.vel_limit;
if (config_.enable_vel_limit) {
vel_des = std::clamp(vel_des, -vel_lim, vel_lim);
}
// 如果速度估计超过容忍阈值 → 报错中断
if (config_.enable_overspeed_error) { // 0.0f to disable
if (!vel_estimate_src) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
if (std::abs(*vel_estimate_src) > 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_->motor_.current_control_.acim_rotor_flux;
float minflux = axis_->motor_.config_.acim_gain_min_flux;
if (fabsf(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_;
//抗齿槽力补偿(前馈)
if (anticogging_valid_ && config_.anticogging.anticogging_enabled) {
torque += config_.anticogging.cogging_map[std::clamp(mod((int)anticogging_pos, 3600), 0, 3600)];
}
//转速闭环控制 & 抗齿槽力补偿
float v_err = 0.0f;
if (config_.control_mode >= CONTROL_MODE_VELOCITY_CONTROL) {
if (!vel_estimate_src) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
v_err = vel_des - *vel_estimate_src;
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_src) {
set_error(ERROR_INVALID_ESTIMATE);
return false;
}
torque = limitVel(config_.vel_limit, *vel_estimate_src, vel_gain, torque);
}
// Torque limiting 限流 + 积分处理
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;
}
}
if (torque_setpoint_output) *torque_setpoint_output = torque;
return true;
}