Description
Base class for all steering path-following PID controllers.
The base class implements the basic functionality to control the error between the location of a sentinel point (a point at a look-ahead distance in front of the vehicle) and the current target point.
The parameters of a steering controller can also be specified through a JSON file; sample JSON input file:
{ "Gains": { "Kp": 0.5, "Ki" : 0.0, "Kd" : 0.0 },
"Lookahead Distance": 20.0 }
Data collection from the steering controller can be started (restarted) and suspended (stopped) as many times as desired. Data collected so far can be written to a file. The tab-separated output ASCII file contains on each line the time, location of the target point, and location of the sentinel point.
#include <ChSteeringController.h>
Public Member Functions | |
virtual | ~ChSteeringController () |
Destructor. | |
void | SetLookAheadDistance (double dist) |
Specify the look-ahead distance. More... | |
const ChVector & | GetSentinelLocation () const |
Return the current location of the sentinel point. More... | |
const ChVector & | GetTargetLocation () const |
Return the current value of the target point. More... | |
std::shared_ptr< ChBezierCurve > | GetPath () const |
Return a pointer to the Bezier curve. | |
virtual void | Reset (const ChVehicle &vehicle) |
Reset the PID controller. More... | |
virtual double | Advance (const ChVehicle &vehicle, double step)=0 |
Advance the state of the PID controller. | |
void | StartDataCollection () |
Start/restart data collection. | |
void | StopDataCollection () |
Suspend/stop data collection. | |
bool | IsDataCollectionEnabled () const |
Return true if data is being collected. | |
bool | IsDataAvailable () const |
Return true if data is available for output. | |
void | WriteOutputFile (const std::string &filename) |
Output data collected so far to the specified file. | |
Protected Member Functions | |
ChSteeringController (std::shared_ptr< ChBezierCurve > path) | |
Construct a steering controller with default parameters. | |
virtual void | CalcTargetLocation ()=0 |
Calculate the current target point location. More... | |
Protected Attributes | |
std::shared_ptr< ChBezierCurve > | m_path |
tracked path (piecewise cubic Bezier curve) | |
double | m_dist |
look-ahead distance | |
ChVector | m_sentinel |
position of sentinel point in global frame | |
ChVector | m_target |
position of target point in global frame | |
double | m_err |
current error (signed distance to target point) | |
double | m_errd |
error derivative | |
double | m_erri |
integral of error | |
utils::CSV_writer * | m_csv |
CSV_writer object for data collection. | |
bool | m_collect |
flag indicating whether or not data is being collected | |
Member Function Documentation
◆ CalcTargetLocation()
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protectedpure virtual |
Calculate the current target point location.
All derived classes must implement this function to calculate the current location of the target point, expressed in the global frame. The location of the sentinel point at the current time is calculated and available in m_sentinel.
Implemented in chrono::vehicle::ChPathSteeringControllerStanley, chrono::vehicle::ChPathSteeringControllerSR, chrono::vehicle::ChPathSteeringControllerXT, chrono::vehicle::ChPathSteeringController, and chrono::synchrono::ChMultiplePathSteeringController.
◆ GetSentinelLocation()
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inline |
Return the current location of the sentinel point.
The return vector is expressed in the global reference frame.
◆ GetTargetLocation()
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inline |
Return the current value of the target point.
The return vector is expressed in the global reference frame.
◆ Reset()
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virtual |
Reset the PID controller.
This function must be called at a configuration where a valid location for the sentinel point can be calculated. The default implementation in the base class simply calculates the new sentinel point location and sets all errors to 0.
Reimplemented in chrono::synchrono::ChMultiplePathSteeringController, chrono::vehicle::ChPathSteeringControllerStanley, chrono::vehicle::ChPathSteeringControllerSR, chrono::vehicle::ChPathSteeringControllerXT, and chrono::vehicle::ChPathSteeringController.
◆ SetLookAheadDistance()
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inline |
Specify the look-ahead distance.
This defines the location of the "sentinel" point (in front of the vehicle, at the given distance from the chassis reference frame).
The documentation for this class was generated from the following files:
- /builds/uwsbel/chrono/src/chrono_vehicle/utils/ChSteeringController.h
- /builds/uwsbel/chrono/src/chrono_vehicle/utils/ChSteeringController.cpp