Files
allwpilib/wpilibc/src/main/native/cpp/simulation/ElevatorSim.cpp
Tyler Veness ac9be78e27 Use stricter C++ type conversions (#4357)
Now, implicit narrowing conversions are only used with wpi::Now(). This
also fixes clang-tidy warnings about C-style casts. For example:
```
== clang-tidy /__w/allwpilib/allwpilib/wpilibNewCommands/src/main/native/include/frc2/command/SwerveControllerCommand.inc ==
/__w/allwpilib/allwpilib/wpilibNewCommands/src/main/native/include/frc2/command/SwerveControllerCommand.inc:95:18: warning: C-style casts are discouraged; use static_cast/const_cast/reinterpret_cast [google-readability-casting]
  auto curTime = units::second_t(m_timer.Get());
                 ^
```
In that case at least, the cast was removed entirely since Get() already
returns a units::second_t.
2022-08-17 13:42:36 -07:00

107 lines
3.6 KiB
C++

// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
#include "frc/simulation/ElevatorSim.h"
#include <wpi/MathExtras.h>
#include "frc/system/NumericalIntegration.h"
#include "frc/system/plant/LinearSystemId.h"
using namespace frc;
using namespace frc::sim;
ElevatorSim::ElevatorSim(const LinearSystem<2, 1, 1>& plant,
const DCMotor& gearbox, double gearing,
units::meter_t drumRadius, units::meter_t minHeight,
units::meter_t maxHeight, bool simulateGravity,
const std::array<double, 1>& measurementStdDevs)
: LinearSystemSim(plant, measurementStdDevs),
m_gearbox(gearbox),
m_drumRadius(drumRadius),
m_minHeight(minHeight),
m_maxHeight(maxHeight),
m_gearing(gearing),
m_simulateGravity(simulateGravity) {}
ElevatorSim::ElevatorSim(const DCMotor& gearbox, double gearing,
units::kilogram_t carriageMass,
units::meter_t drumRadius, units::meter_t minHeight,
units::meter_t maxHeight, bool simulateGravity,
const std::array<double, 1>& measurementStdDevs)
: LinearSystemSim(LinearSystemId::ElevatorSystem(gearbox, carriageMass,
drumRadius, gearing),
measurementStdDevs),
m_gearbox(gearbox),
m_drumRadius(drumRadius),
m_minHeight(minHeight),
m_maxHeight(maxHeight),
m_gearing(gearing),
m_simulateGravity(simulateGravity) {}
bool ElevatorSim::WouldHitLowerLimit(units::meter_t elevatorHeight) const {
return elevatorHeight < m_minHeight;
}
bool ElevatorSim::WouldHitUpperLimit(units::meter_t elevatorHeight) const {
return elevatorHeight > m_maxHeight;
}
bool ElevatorSim::HasHitLowerLimit() const {
return WouldHitLowerLimit(units::meter_t{m_y(0)});
}
bool ElevatorSim::HasHitUpperLimit() const {
return WouldHitUpperLimit(units::meter_t{m_y(0)});
}
units::meter_t ElevatorSim::GetPosition() const {
return units::meter_t{m_y(0)};
}
units::meters_per_second_t ElevatorSim::GetVelocity() const {
return units::meters_per_second_t{m_x(1)};
}
units::ampere_t ElevatorSim::GetCurrentDraw() const {
// I = V / R - omega / (Kv * R)
// Reductions are greater than 1, so a reduction of 10:1 would mean the motor
// is spinning 10x faster than the output.
// v = r w, so w = v / r
units::meters_per_second_t velocity{m_x(1)};
units::radians_per_second_t motorVelocity =
velocity / m_drumRadius * m_gearing * 1_rad;
// Perform calculation and return.
return m_gearbox.Current(motorVelocity, units::volt_t{m_u(0)}) *
wpi::sgn(m_u(0));
}
void ElevatorSim::SetInputVoltage(units::volt_t voltage) {
SetInput(Vectord<1>{voltage.value()});
}
Vectord<2> ElevatorSim::UpdateX(const Vectord<2>& currentXhat,
const Vectord<1>& u, units::second_t dt) {
auto updatedXhat = RKDP(
[&](const Vectord<2>& x, const Vectord<1>& u_) -> Vectord<2> {
Vectord<2> xdot = m_plant.A() * x + m_plant.B() * u;
if (m_simulateGravity) {
xdot += Vectord<2>{0.0, -9.8};
}
return xdot;
},
currentXhat, u, dt);
// Check for collision after updating x-hat.
if (WouldHitLowerLimit(units::meter_t{updatedXhat(0)})) {
return Vectord<2>{m_minHeight.value(), 0.0};
}
if (WouldHitUpperLimit(units::meter_t{updatedXhat(0)})) {
return Vectord<2>{m_maxHeight.value(), 0.0};
}
return updatedXhat;
}