得到 PID

 

java codes

 

public class StandAloneServer {
	static public final int PORT = 8182;

	private final AutopubStore store = new CassandraAutopubStore();

	private final Component component = new Component();

	/** launch */
	public StandAloneServer() throws Exception {
		AutopubResource.setStorage(store);
		System.out.println("Starting REST server on http://"
				+ InetAddress.getLocalHost().getHostAddress() + ":" + PORT
				+ "/");
		component.getServers().add(Protocol.HTTP, PORT);
		component.getDefaultHost().attach(new OpenAutopub());
		component.getDefaultHost().attach("/resources",new StaticResourceApplication());
		component.getClients().add(Protocol.CLAP);
		component.start();
	}

	public void stop() throws Exception {
		component.stop();
		store.close();
	}

	/** entry point */
	static public void main(String[] args) throws Exception {
		String option="start";
		if (args.length !=0){
			option=args[0];
		}
		if ("start".equals(option)) {
			new StandAloneServer();
			String pid=getCurrentPid();
			System.out.println(pid);
			savePid(pid);
		} else if("stop".equals(option)){
			String pid = getPid();
			killPid(pid);
			savePid(null);
		}
		
	}
	public static String getCurrentPid() throws IOException,InterruptedException {  
	  Vector<String> commands=new Vector<String>();  
	     commands.add("/bin/bash");  
	     commands.add("-c");  
	     commands.add("echo $PPID");  
	     ProcessBuilder pb=new ProcessBuilder(commands);  
	       
	     Process pr=pb.start();  
	     pr.waitFor();  
	     if (pr.exitValue()==0) {  
	       BufferedReader outReader=new BufferedReader(new InputStreamReader(pr.getInputStream()));  
	       return outReader.readLine().trim();  
	     } else {  
	       System.out.println("Error while getting PID");  
	       return "";  
	     }  
	}
	public static void savePid(String pid) throws IOException{
		File f = new File("pid");
		
		if(pid ==null){
			FileWriter fw=new FileWriter(f);
			fw.write("");
			fw.close();
		} else{
			if (f.exists() && f.length()>0) {
				System.out.println("there is exsiting server running");
			}
			FileWriter fw=new FileWriter(f);
			fw.write(pid);
			fw.close();
		}
	}
	
	public static String getPid() throws IOException{
		File f = new File("pid");
		if (!f.exists()) return null;
		BufferedReader br = new BufferedReader(new FileReader(f)); 
		String pid=br.readLine();
		br.close();
		return pid;
	}
	
	public static void killPid(String pid) throws IOException{
		 Vector<String> commands=new Vector<String>();  
	     commands.add("/bin/bash");  
	     commands.add("-c");  
	     commands.add("kill "+pid);  
	     ProcessBuilder pb=new ProcessBuilder(commands);  
	       
	     Process pr=pb.start();  
	}
}

 

ant build.xml

 

	<target name="startup" depends="compile" >
		<java classname="com.hp.hpl.miul.openautopub.app.StandAloneServer" fork="true">
			<arg line="start"/>
			<classpath>
				<path refid="classpath"/>
				<pathelement location="target/ant-classes"/>
				<pathelement location="src/main/resources"/>
				<!--run functional test case -->
				<pathelement location="src/test/resources"/>
			</classpath>
		</java>
	</target>
	
	<target name="shutdown" depends="compile">
		<java classname="com.hp.hpl.miul.openautopub.app.StandAloneServer">
			<arg line="stop"/>
			<classpath>
				<path refid="classpath"/>
				<pathelement location="target/ant-classes"/>
				<pathelement location="src/main/resources"/>
				<!--run functional test case -->
				<pathelement location="src/test/resources"/>
			</classpath>
		</java>
	</target>
 
当你得到PID控制器的输出值后,你可以使用下面的伪代码来实现温控程序: 1. 读取当前的温度值 2. 将温度值传递给PID控制器并获取输出值 3. 将PID输出值转换为控制器的运行状态,例如开/关加热器或调节风扇速度 4. 等待一段时间(例如1秒) 5. 返回第1步 下面是一个示例代码,用于控制加热器的开/关状态,以实现温度控制: ``` #include <PID_v1.h> // Define the PID parameters double Kp = 1; double Ki = 0; double Kd = 0; // Define the variables for PID control double input, output, setpoint; PID pid(&input, &output, &setpoint, Kp, Ki, Kd, DIRECT); // Define the pins for the heater and the temperature sensor int heaterPin = 10; int tempSensorPin = A0; void setup() { // Set up the heater pin as an output pinMode(heaterPin, OUTPUT); // Set up the temperature sensor pin as an input pinMode(tempSensorPin, INPUT); // Initialize the PID control pid.SetMode(AUTOMATIC); pid.SetOutputLimits(0, 255); // Set the output limits to the range of the PWM signal for the heater setpoint = 25; // Set the desired temperature to 25 degrees Celsius } void loop() { // Read the current temperature value input = analogRead(tempSensorPin); // Compute the PID output pid.Compute(); // Convert the PID output to the heater control signal if (output > 0) { digitalWrite(heaterPin, HIGH); analogWrite(heaterPin, output); } else { digitalWrite(heaterPin, LOW); } // Wait for 1 second delay(1000); } ``` 这个示例代码使用了Arduino的PID库来实现PID控制器。在`setup()`函数中,我们设置了PID参数和控制器的输出范围。在`loop()`函数中,我们读取温度传感器的值并传递给PID控制器,然后将PID输出值转换为加热器的开/关状态,并等待1秒钟。
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