A PND (proportional to Q and N derivatives of Q) controller that computes the control signal:
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| Controller (const double update_fraction) |
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| Controller (Controller &&)=default |
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Controller & | operator= (Controller &&)=default |
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| Controller (const Controller &)=default |
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Controller & | operator= (const Controller &)=default |
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DataVector | operator() (const double time, const DataVector ×cales, const std::array< DataVector, DerivOrder > &q_and_derivs, double q_time_offset, double deriv_time_offset) |
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void | assign_time_between_updates (const double current_min_timescale) |
| | Takes the current minimum of all timescales for a specific control system and uses that to set the time between updates.
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bool | is_ready (const double time) |
| | Returns true if the controller is ready to calculate the control signal.
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double | next_expiration_time (const double current_expiration_time) |
| | Calculates the new expiration time as the old expiration time plus the time between updates.
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void | set_initial_update_time (const double initial_time) |
| | Sets the last time updated to the initial time.
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double | get_update_fraction () const |
| | Return the update fraction.
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void | pup (PUP::er &p) |
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template<size_t DerivOrder>
class Controller< DerivOrder >
A PND (proportional to Q and N derivatives of Q) controller that computes the control signal:
\[ U(t) = \sum_{k=0}^{N} a_{k} \frac{d^kQ}{dt^k} \]
where N is specified by the template parameter DerivOrder.
If an averager is used for q_and_derivs (as we typically do), there is an induced time offset, \(\Delta t\), due to the time-weighted averaging. Therefore, the q_and_derivs that we have in hand are at some time \(t_{0}\). However, we desire q_and_derivs at the current time \(t = t_{0} + \Delta t\) to determine the appropriate control signal. We accomplish this by Taylor expanding \(Q(t_{0} + \Delta t)\). The averager allows for averaging of \(Q\) and its derivatives OR to not average \(Q\) while still averaging the derivatives (the derivatives are always averaged in order to reduce noise due to numerical differentiation). When they are both averaged, the time offset will be identical for \(Q\) and the derivatives, i.e. q_time_offset = deriv_time_offset. If an unaveraged \(Q\) is used, then the time offset associated with \(Q\) is zero, i.e. q_time_offset=0. and the derivative time offset, deriv_time_offset, remains non-zero.