Running a process from C++

 When you want to run a separate process from C++:

• Change working directory if the process loads files.
• Start process (Windows, Linux). Note that this is a blocking operation and needs to be done in a thread.

Vertical Landing Rocket Competition

This year's Teknofest has a Vertical Landing Rocket Competition. We can divide the control problem into two:

1. Stabilize orientation so that the thruster points in downward direction.
2. Control vertical speed to achieve a soft landing.

Orientation can be stabilized via passive fins or active side jets. Since there isn't much time for manufacturing and testing, using fins seems to be the easiest choice.

Assuming that the fins achieve close to zero yaw and pitch, speed can be controlled by changing the thrust via valve control using PID.  I wrote a Matlab script that can be used as a starting point:

I also wrote a simple open loop code that has no control, you can find it here.

C++: Starting and stopping a thread

	//Demonstrates how a thread can be started and stopped
	#include <iostream>
	#include <thread>
	#include <chrono>
	bool isRunning = false;
	class MyClass {
	public:
	~MyClass() {
	if (worker != nullptr) {
	isRunning = false;
	worker->join();
	delete worker;
	std::cout << "worker deleted" << std::endl;
	}
	}
	static void Run(double duration_s) {
	while (isRunning) {
	std::cout << "isRunning" << std::endl;
	auto startTime = std::chrono::steady_clock::now();
	auto endTime = startTime + std::chrono::duration<double>(duration_s);
	std::this_thread::sleep_until(endTime);
	}
	std::cout << "thread ended" << std::endl;
	}
	void Start(double duration_s) {
	isRunning = true;
	worker = new std::thread(Run, duration_s);
	}
	void Stop() {
	isRunning = false;
	}
	private:
	std::thread* worker;
	};
	int main() {
	MyClass m;
	m.Start(1);
	auto startTime = std::chrono::steady_clock::now();
	auto endTime = startTime + std::chrono::duration<double>(3);
	std::this_thread::sleep_until(endTime);
	m.Stop();
	std::cout << "Main ended. Press enter...\n";
	std::cin.get();
	}

view raw startStopThread.cpp hosted with ❤ by GitHub