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Conception/drake-master/systems/primitives/saturation.cc

101 lines
3.3 KiB

#include "drake/systems/primitives/saturation.h"
#include <algorithm>
#include <limits>
#include "drake/common/default_scalars.h"
namespace drake {
namespace systems {
template <typename T>
Saturation<T>::Saturation(int input_size)
: min_max_ports_enabled_(true),
input_size_(input_size),
max_value_(VectorX<T>::Constant(input_size,
std::numeric_limits<double>::infinity())),
min_value_(VectorX<T>::Constant(
input_size, -std::numeric_limits<double>::infinity())) {
// Checks if input size is a positive integer.
DRAKE_THROW_UNLESS(input_size_ > 0);
// Input and outputs are of same dimension.
input_port_index_ =
this->DeclareInputPort(kUseDefaultName, kVectorValued, input_size_)
.get_index();
max_value_port_index_ =
this->DeclareInputPort(kUseDefaultName, kVectorValued, input_size_)
.get_index();
min_value_port_index_ =
this->DeclareInputPort(kUseDefaultName, kVectorValued, input_size_)
.get_index();
this->DeclareVectorOutputPort(kUseDefaultName, input_size_,
&Saturation::CalcSaturatedOutput)
.get_index();
}
template <typename T>
Saturation<T>::Saturation(const VectorX<T>& min_value,
const VectorX<T>& max_value)
: min_max_ports_enabled_(false),
input_size_(min_value.size()),
max_value_(max_value),
min_value_(min_value) {
// Checks if input size is a positive integer.
DRAKE_THROW_UNLESS(input_size_ > 0);
// Checks if limits are of same dimensions.
DRAKE_THROW_UNLESS(min_value.size() == max_value.size());
DRAKE_THROW_UNLESS((min_value_.array() <= max_value_.array()).all());
input_port_index_ =
this->DeclareInputPort(kUseDefaultName, kVectorValued, input_size_)
.get_index();
this->DeclareVectorOutputPort(kUseDefaultName, input_size_,
&Saturation::CalcSaturatedOutput)
.get_index();
}
template <typename T>
void Saturation<T>::CalcSaturatedOutput(const Context<T>& context,
BasicVector<T>* output_vector) const {
// Initializes on the default values.
VectorX<T> u_min = min_value_, u_max = max_value_;
// Extracts the min and/or max values if they are present in the input ports.
if (min_max_ports_enabled_) {
const bool has_min = get_min_value_port().HasValue(context);
const bool has_max = get_max_value_port().HasValue(context);
// Throws an error in case neither of the inputs are connected in
// the case of the variable version of the Saturation system.
DRAKE_THROW_UNLESS(has_min || has_max);
if (has_min) {
u_min = get_min_value_port().Eval(context);
}
if (has_max) {
u_max = get_max_value_port().Eval(context);
}
}
DRAKE_THROW_UNLESS((u_min.array() <= u_max.array()).all());
// Evaluates the input port.
const auto& u = get_input_port().Eval(context);
// Evaluates the state output port.
auto y = output_vector->get_mutable_value();
// Loop through and set the saturation values.
for (int i = 0; i < u_min.size(); ++i) {
using std::clamp;
y[i] = clamp(u[i], u_min[i], u_max[i]);
}
}
} // namespace systems
} // namespace drake
DRAKE_DEFINE_CLASS_TEMPLATE_INSTANTIATIONS_ON_DEFAULT_SCALARS(
class ::drake::systems::Saturation)