添加GPS传感器
1. 添加GPS实体
step1: 首先在机器人模型的Robot->children中添加一个GPS节点
step2: 然后在GPS节点->children中添加一个solid固件
step3: 设置这个solid固件的children中添加shape节点，并设置外观和形状。具体设置底部半径为0.02 高度为0.05，设置偏移量为（x=0,y=0.03,z=0）。
这里为了区别其他传感器我们使用了这个圆锥形的形状作为GPS
step4: 最后我们需要设置GPS传感器的名称，以便我们在程序中读取GPS传感器的数据。
注意：添加GPS的过程中不设置boundingObject属性和 physics属性。
2. 添加GPS 控制接口代码
完整的代码块：
#include <webots/Robot.hpp>
#include <webots/GPS.hpp>
#include <webots/DistanceSensor.hpp>
#include <webots/Motor.hpp>
#include <webots/Keyboard.hpp>
#include <stdio.h>
#define TIME_STEP 64
// All the webots classes are defined in the "webots" namespace
using namespace webots;
int main(int argc, char **argv) {
// create the Robot instance.
Robot *robot = new Robot();
Keyboard kb;
DistanceSensor *ds[2];
char dsNames[2][10] = {
"ds_right","ds_left"};
for (int i = 0; i < 2; i++) {
ds[i] = robot->getDistanceSensor(dsNames[i]);
ds[i]->enable(TIME_STEP);
}
GPS *gps;
gps = robot->getGPS("global_gps");
gps->enable(TIME_STEP);
// initialise motors
Motor *wheels[4];
char wheels_names[4][8] = {
"wheel1", "wheel2", "wheel3", "wheel4"};
for (int i = 0; i < 4; i++) {
wheels[i] = robot->getMotor(wheels_names[i]);
wheels[i]->setPosition(INFINITY);
wheels[i]->setVelocity(0);
}
printf("init successd ...\n");
kb.enable(TIME_STEP);
double leftSpeed = 0.0;
double rightSpeed = 0.0;
// Main loop:
// - perform simulation steps until Webots is stopping the controller
while (robot->step(TIME_STEP) != -1)
{
int key = kb.getKey();
if(key== 315)
{
leftSpeed = 3.0;
rightSpeed = 3.0;
}
else if(key== 317)
{
leftSpeed = -3.0;
rightSpeed = -3.0;
}
else if(key== 314)
{
leftSpeed = -3.0;
rightSpeed = 3.0;
}
else if(key== 316)
{
leftSpeed = 3.0;
rightSpeed = -3.0;
}
else
{
leftSpeed = 0.0;
rightSpeed = 0.0;
}
std::cout<< " Right Sensor Value:" <<ds[0]->getValue() << " Left Sensor Value:" <<ds[1]->getValue() <<std::endl;
std::cout<< "GPS Value X: " <<gps->getValues()[0]
<< " Y: " <<gps->getValues()[1]<< " Z: " <<gps->getValues()[2] <<std::endl;
wheels[0]->setVelocity(leftSpeed);
wheels[1]->setVelocity(rightSpeed);
wheels[2]->setVelocity(leftSpeed);
wheels[3]->setVelocity(rightSpeed);
};
// Enter here exit cleanup code.
delete robot;
return 0;
}
相比于利用键盘控制小车的demo,在这里增加了GPS初始化和打印GPS信息两个部分。
在控制器中增加代码块，用于初始化GPS
GPS *gps;
gps = robot->getGPS("global_gps");
gps->enable(TIME_STEP);
打印GPS传感器的值
std::cout<< "GPS Value X: " <<gps->getValues()[0]
<< " Y: " <<gps->getValues()[1]<< " Z: " <<gps->getValues()[2] <<std::endl;
GPS传感器的接口函数可以在[1]处查到各语言版本的接口类型，这里我们只用到了 enable 和 getValues 两个函数。
3. 运行效果
在console框中可以看到输出的GPS信息，GPS安装的有点难看，美化的工作就留给大家了。
修改的模型文件可在此处下载
：
参考资料
[1] https://cyberbotics.com/doc/reference/gps?tab-language=c++
[2] 模型文件：https://download.csdn.net/download/crp997576280/12351539
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