Public Member Functions |
| double | getCurrentCmd () |
| | Return current command for this PID controller.
|
| void | getCurrentPIDErrors (double *pe, double *ie, double *de) |
| | Return PID error terms for the controller.
|
| void | getGains (double &p, double &i, double &d, double &i_max, double &i_min) |
| | Get PID gains for the controller.
|
| bool | init (const ros::NodeHandle &n) |
| | Initialize PID with the parameters in a NodeHandle namespace.
|
| bool | initParam (const std::string &prefix) |
| | Initialize PID with the parameters in a namespace.
|
| void | initPid (double P, double I, double D, double I1, double I2) |
| | Initialize PID-gains and integral term limits:[iMax:iMin]-[I1:I2].
|
| bool | initXml (TiXmlElement *config) |
| Pid & | operator= (const Pid &p) |
| | Pid (double P=0.0, double I=0.0, double D=0.0, double I1=0.0, double I2=-0.0) |
| | Constructor, zeros out Pid values when created and initialize Pid-gains and integral term limits:[iMax:iMin]-[I1:I2].
|
| void | reset () |
| | Reset the state of this PID controller.
|
| void | setCurrentCmd (double cmd) |
| | Set current command for this PID controller.
|
| void | setGains (double P, double I, double D, double i_max, double i_min) |
| | Set PID gains for the controller.
|
| double | updatePid (double p_error, ros::Duration dt) |
| | Update the Pid loop with nonuniform time step size.
|
| double | updatePid (double error, double error_dot, ros::Duration dt) |
| | Update the Pid loop with nonuniform time step size. This update call allows the user to pass in a precomputed derivative error.
|
| | ~Pid () |
| | Destructor of Pid class.
|
Private Attributes |
| double | cmd_ |
| double | d_error_ |
| double | d_gain_ |
| double | i_error_ |
| double | i_gain_ |
| double | i_max_ |
| double | i_min_ |
| double | p_error_ |
| double | p_error_last_ |
| double | p_gain_ |
A basic pid class.
This class implements a generic structure that can be used to create a wide range of pid controllers. It can function independently or be subclassed to provide more specific controls based on a particular control loop.
In particular, this class implements the standard pid equation:
where:
given:
-
.
ROS interface
- Parameters:
-
| p | Proportional gain |
| d | Derivative gain |
| i | Integral gain |
| i_clamp | Min/max bounds for the integral windup, the clamp is applied to the  and not the  |
Usage
To use the Pid class, you should first call some version of init() (in non-realtime) and then call updatePid() at every update step. For example:
control_toolbox::Pid pid;
pid.initPid(6.0, 1.0, 2.0, 0.3, -0.3);
double position_desi_ = 0.5;
...
ros::Time last_time = ros::Time::now();
while (true) {
ros::Time time = ros::Time::now();
double effort = pid.updatePid(currentPosition() - position_desi_, time - last_time);
last_time = time;
}
Definition at line 106 of file pid.h.
