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allwpilib/simulation/frc_gazebo_plugins/servo/src/servo.h

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2.3 KiB
C++

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2016. All Rights Reserved. */
/* Open Source Software - may be modified and shared by FRC teams. The code */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project. */
/*----------------------------------------------------------------------------*/
#pragma once
#include <string>
#include <gazebo/gazebo.hh>
#include "simulation/gz_msgs/msgs.h"
/**
* \brief Plugin for controlling a servo.
*
* This plugin subscribes to a topic to get a signal in the range
* [-1,1]. Every physics update the joint's torque is set as
* multiplier*signal.
*
* To add a servo to your robot, add the following XML to your robot
* model:
*
* <plugin name="my_servo" filename="libservo.so">
* <joint>Joint Name</joint>
* <topic>/gzebo/frc/simulator/pwm/1</topic>
* <zero_position>0</zero_position>
* </plugin>
*
* - `link`: Name of the link the servo is attached to.
* - `topic`: Optional. Message type should be gazebo.msgs.Float64.
*/
class Servo : public gazebo::ModelPlugin {
public:
/// \brief load the servo and configure it according to the sdf
void Load(gazebo::physics::ModelPtr model, sdf::ElementPtr sdf);
/// \brief Update the torque on the joint from the dc motor each timestep.
void Update(const gazebo::common::UpdateInfo& info);
private:
/// \brief Topic to read control signal from.
std::string topic;
/// \brief the pwm signal limited to the range [-1,1]
double signal;
/// \brief the torque of the motor in kg/cm
double torque;
/// \brief the joint that this servo moves
gazebo::physics::JointPtr joint;
/// \brief Callback for receiving msgs and storing the signal
void Callback(const gazebo::msgs::ConstFloat64Ptr& msg);
/// \brief The model to which this is attached
gazebo::physics::ModelPtr model;
/// \brief The pointer to the world update function
gazebo::event::ConnectionPtr updateConn;
/// \brief The node on which we're advertising torque
gazebo::transport::NodePtr node;
/// \brief The subscriber for the PWM signal
gazebo::transport::SubscriberPtr sub;
};