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allwpilib/wpilibc/src/main/native/include/frc/drive/DifferentialDrive.h

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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.
#pragma once
#include <string>
#include <wpi/sendable/Sendable.h>
#include <wpi/sendable/SendableHelper.h>
#include "frc/drive/RobotDriveBase.h"
namespace frc {
#if defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable : 4996) // was declared deprecated
#elif defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
#elif defined(__GNUC__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#endif
class SpeedController;
/**
* A class for driving differential drive/skid-steer drive platforms such as
* the Kit of Parts drive base, "tank drive", or West Coast Drive.
*
* These drive bases typically have drop-center / skid-steer with two or more
* wheels per side (e.g., 6WD or 8WD). This class takes a MotorController per
* side. For four and six motor drivetrains, construct and pass in
* MotorControllerGroup instances as follows.
*
* Four motor drivetrain:
* @code{.cpp}
* class Robot {
* public:
* frc::PWMVictorSPX m_frontLeft{1};
* frc::PWMVictorSPX m_rearLeft{2};
* frc::MotorControllerGroup m_left{m_frontLeft, m_rearLeft};
*
* frc::PWMVictorSPX m_frontRight{3};
* frc::PWMVictorSPX m_rearRight{4};
* frc::MotorControllerGroup m_right{m_frontRight, m_rearRight};
*
* frc::DifferentialDrive m_drive{m_left, m_right};
* };
* @endcode
*
* Six motor drivetrain:
* @code{.cpp}
* class Robot {
* public:
* frc::PWMVictorSPX m_frontLeft{1};
* frc::PWMVictorSPX m_midLeft{2};
* frc::PWMVictorSPX m_rearLeft{3};
* frc::MotorControllerGroup m_left{m_frontLeft, m_midLeft, m_rearLeft};
*
* frc::PWMVictorSPX m_frontRight{4};
* frc::PWMVictorSPX m_midRight{5};
* frc::PWMVictorSPX m_rearRight{6};
* frc::MotorControllerGroup m_right{m_frontRight, m_midRight, m_rearRight};
*
* frc::DifferentialDrive m_drive{m_left, m_right};
* };
* @endcode
*
* A differential drive robot has left and right wheels separated by an
* arbitrary width.
*
* Drive base diagram:
* <pre>
* |_______|
* | | | |
* | |
* |_|___|_|
* | |
* </pre>
*
* Each Drive() function provides different inverse kinematic relations for a
* differential drive robot. Motor outputs for the right side are negated, so
* motor direction inversion by the user is usually unnecessary.
*
* This library uses the NED axes convention (North-East-Down as external
* reference in the world frame):
* http://www.nuclearprojects.com/ins/images/axis_big.png.
*
* The positive X axis points ahead, the positive Y axis points to the right,
* and the positive Z axis points down. Rotations follow the right-hand rule, so
* clockwise rotation around the Z axis is positive.
*
* Inputs smaller then 0.02 will be set to 0, and larger values will be scaled
* so that the full range is still used. This deadband value can be changed
* with SetDeadband().
*/
class DifferentialDrive : public RobotDriveBase,
public wpi::Sendable,
public wpi::SendableHelper<DifferentialDrive> {
public:
struct WheelSpeeds {
double left = 0.0;
double right = 0.0;
};
/**
* Construct a DifferentialDrive.
*
* To pass multiple motors per side, use a MotorControllerGroup. If a motor
* needs to be inverted, do so before passing it in.
*/
DifferentialDrive(SpeedController& leftMotor, SpeedController& rightMotor);
~DifferentialDrive() override = default;
DifferentialDrive(DifferentialDrive&&) = default;
DifferentialDrive& operator=(DifferentialDrive&&) = default;
/**
* Arcade drive method for differential drive platform.
*
* Note: Some drivers may prefer inverted rotation controls. This can be done
* by negating the value passed for rotation.
*
* @param xSpeed The speed at which the robot should drive along the X
* axis [-1.0..1.0]. Forward is positive.
* @param zRotation The rotation rate of the robot around the Z axis
* [-1.0..1.0]. Clockwise is positive.
* @param squareInputs If set, decreases the input sensitivity at low speeds.
*/
void ArcadeDrive(double xSpeed, double zRotation, bool squareInputs = true);
/**
* Curvature drive method for differential drive platform.
*
* The rotation argument controls the curvature of the robot's path rather
* than its rate of heading change. This makes the robot more controllable at
* high speeds.
*
* @param xSpeed The robot's speed along the X axis [-1.0..1.0].
* Forward is positive.
* @param zRotation The normalized curvature [-1.0..1.0]. Clockwise is
* positive.
* @param allowTurnInPlace If set, overrides constant-curvature turning for
* turn-in-place maneuvers. zRotation will control
* turning rate instead of curvature.
*/
void CurvatureDrive(double xSpeed, double zRotation, bool allowTurnInPlace);
/**
* Tank drive method for differential drive platform.
*
* @param leftSpeed The robot left side's speed along the X axis
* [-1.0..1.0]. Forward is positive.
* @param rightSpeed The robot right side's speed along the X axis
* [-1.0..1.0]. Forward is positive.
* @param squareInputs If set, decreases the input sensitivity at low speeds.
*/
void TankDrive(double leftSpeed, double rightSpeed, bool squareInputs = true);
/**
* Arcade drive inverse kinematics for differential drive platform.
*
* Note: Some drivers may prefer inverted rotation controls. This can be done
* by negating the value passed for rotation.
*
* @param xSpeed The speed at which the robot should drive along the X
* axis [-1.0..1.0]. Forward is positive.
* @param zRotation The rotation rate of the robot around the Z axis
* [-1.0..1.0]. Clockwise is positive.
* @param squareInputs If set, decreases the input sensitivity at low speeds.
*/
static WheelSpeeds ArcadeDriveIK(double xSpeed, double zRotation,
bool squareInputs = true);
/**
* Curvature drive inverse kinematics for differential drive platform.
*
* The rotation argument controls the curvature of the robot's path rather
* than its rate of heading change. This makes the robot more controllable at
* high speeds.
*
* @param xSpeed The robot's speed along the X axis [-1.0..1.0].
* Forward is positive.
* @param zRotation The normalized curvature [-1.0..1.0]. Clockwise is
* positive.
* @param allowTurnInPlace If set, overrides constant-curvature turning for
* turn-in-place maneuvers. zRotation will control
* turning rate instead of curvature.
*/
static WheelSpeeds CurvatureDriveIK(double xSpeed, double zRotation,
bool allowTurnInPlace);
/**
* Tank drive inverse kinematics for differential drive platform.
*
* @param leftSpeed The robot left side's speed along the X axis
* [-1.0..1.0]. Forward is positive.
* @param rightSpeed The robot right side's speed along the X axis
* [-1.0..1.0]. Forward is positive.
* @param squareInputs If set, decreases the input sensitivity at low speeds.
*/
static WheelSpeeds TankDriveIK(double leftSpeed, double rightSpeed,
bool squareInputs = true);
void StopMotor() override;
std::string GetDescription() const override;
void InitSendable(wpi::SendableBuilder& builder) override;
private:
SpeedController* m_leftMotor;
SpeedController* m_rightMotor;
};
#if defined(_MSC_VER)
#pragma warning(pop)
#elif defined(__clang__)
#pragma clang diagnostic pop
#elif defined(__GNUC__)
#pragma GCC diagnostic pop
#endif
} // namespace frc