Description
A rotation q=f(s) provided from a rotation sample, continuously updated by the user, behaving as a ZOH (zero order hold) of FOH (first order).
You must keep the setpoint q updated via multiple calls to SetSetpoint(), for example calling SetSetpoint() at each timestep in the simulation loop. It is assumed that one will later evaluate Get_q(), Get_w_loc() etc. in close vicinity of the setpoint (setpoint history is not saved), preferably ecactly at the same s, but in vicinity of s there will be extrapolation (after last s) and interpolation (before last s) according to: If in ZOH mode: rotation q will persist indefinitely until next call, angular velocity and angular acceleration will be zero. If in FOH mode: rotation q will interpolate linearly from the previous value, angular velocity will be constant, angular acceleration will be zero. Default: uses FOH mode. Use SetMode() to change it.
#include <ChFunctionRotation_setpoint.h>
Public Types | |
| enum | eChSetpointMode { ZOH, FOH, OVERRIDE } |
| Type of setpoint interpolation/extrapolation - zero order hold, first order hold, etc. More... | |
Public Member Functions | |
| ChFunctionRotation_setpoint (const ChFunctionRotation_setpoint &other) | |
| virtual ChFunctionRotation_setpoint * | Clone () const override |
| "Virtual" copy constructor. | |
| void | SetMode (eChSetpointMode mmode) |
| Sets the extrapolation/interpolation mode. | |
| eChSetpointMode | GetMode () |
| Gets the extrapolation/interpolation mode. | |
| void | Reset (double ms=0) |
| Use this to go back to s=0 (the SetSetpoint() function works only if called at increasing s values) | |
| virtual void | SetSetpoint (ChQuaternion<> q_setpoint, double s) |
| Set the rotation setpoint, and compute its derivatives (angular speed, angular acceleration) automatically by backward differentiation (only if s is called at increasing small steps, most often s is time). More... | |
| virtual void | SetSetpointAndDerivatives (ChQuaternion<> q_setpoint, ChVector<> w_loc_setpoint, ChVector<> a_loc_setpoint) |
| Set the setpoint, and also its derivatives (angular velocity, angular acceleration). More... | |
| virtual ChQuaternion | Get_q (double s) const override |
| Return the q value of the function, at s, as q=f(s). | |
| virtual ChVector | Get_w_loc (double s) const override |
| Return the derivative of the rotation function, at s, expressed as angular velocity w in local frame. | |
| virtual ChVector | Get_a_loc (double s) const override |
| Return the derivative of the rotation function, at s, expressed as angular acceleration in local frame. | |
| virtual void | ArchiveOUT (ChArchiveOut &marchive) override |
| Method to allow serialization of transient data to archives. | |
| virtual void | ArchiveIN (ChArchiveIn &marchive) override |
| Method to allow de-serialization of transient data from archives. | |
 Public Member Functions inherited from chrono::ChFunctionRotation | |
| ChFunctionRotation (const ChFunctionRotation &other) | |
| virtual void | Estimate_s_domain (double &smin, double &smax) const |
| Return an estimate of the domain of the function argument. More... | |
| virtual void | Update (const double t) |
| Update could be implemented by children classes, ex. to launch callbacks. | |
Member Enumeration Documentation
◆ eChSetpointMode
Type of setpoint interpolation/extrapolation - zero order hold, first order hold, etc.
| Enumerator | |
|---|---|
| ZOH | Zero Order Hold: q constant, w = a = 0 in neighbour of setpoint s. |
| FOH | First Order Hold: q linear, w constant, a = 0 in neighbour of setpoint s. |
| OVERRIDE | p, w, a are set via SetSetpointAndDerivatives() and will be considered constant in Get_q(s) regardless of s until next SetSetpointAndDerivatives() |
Member Function Documentation
◆ SetSetpoint()
|
virtual |
Set the rotation setpoint, and compute its derivatives (angular speed, angular acceleration) automatically by backward differentiation (only if s is called at increasing small steps, most often s is time).
Note: each time must be called with increasing s so that internally it add sthe 'new' setpoint and scrolls the previous samples for computing extrapolation/interpolation, but if called multiple times with exactly the same s value, the buffer of past samples is not scrolled: it just recompute setpoint and derivatives according to the 'updated' setpoint. If in ZOH mode: rotation q will persist indefinitely until next call, angular velocity and angular acceleration will be zero. If in FOH mode: rotation q will interpolate linearly from the previous value, angular velocity will be constant, angular acceleration will be zero.
◆ SetSetpointAndDerivatives()
|
inlinevirtual |
Set the setpoint, and also its derivatives (angular velocity, angular acceleration).
Moreover, changes the mode to eChSetpointMode::OVERRIDE, so all values will persist indefinitely until next call, that is multiple calls to Get_q(s) Get_w_loc() etc. will give same results (non interpolated) regardless of s.
The documentation for this class was generated from the following files:
- /builds/uwsbel/chrono/src/chrono/motion_functions/ChFunctionRotation_setpoint.h
- /builds/uwsbel/chrono/src/chrono/motion_functions/ChFunctionRotation_setpoint.cpp
