universal_robots_ros_driver/src/ur_realtime_communication.cpp

/*
 * ur_realtime_communication.cpp
 *
 * Copyright 2015 Thomas Timm Andersen
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "ur_modern_driver/ur_realtime_communication.h"

UrRealtimeCommunication::UrRealtimeCommunication(
		std::condition_variable& msg_cond, std::string host,
		unsigned int safety_count_max) {
	robot_state_ = new RobotStateRT(msg_cond);
	bzero((char *) &serv_addr_, sizeof(serv_addr_));
	sockfd_ = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd_ < 0) {
		print_fatal("ERROR opening socket");
	}
	server_ = gethostbyname(host.c_str());
	if (server_ == NULL) {
		print_fatal("ERROR, no such host");
	}
	serv_addr_.sin_family = AF_INET;
	bcopy((char *) server_->h_addr, (char *)&serv_addr_.sin_addr.s_addr, server_->h_length);
	serv_addr_.sin_port = htons(30003);
	flag_ = 1;
	setsockopt(sockfd_, IPPROTO_TCP, TCP_NODELAY, (char *) &flag_, sizeof(int));
	setsockopt(sockfd_, IPPROTO_TCP, TCP_QUICKACK, (char *) &flag_, sizeof(int));
	setsockopt(sockfd_, SOL_SOCKET, SO_REUSEADDR, (char *) &flag_, sizeof(int));
	fcntl(sockfd_, F_SETFL, O_NONBLOCK);
	connected_ = false;
	keepalive_ = false;
	safety_count_ = safety_count_max + 1;
	safety_count_max_ = safety_count_max;
}

bool UrRealtimeCommunication::start() {
	fd_set writefds;
	struct timeval timeout;

	keepalive_ = true;
	print_debug("Realtime port: Connecting...");

	connect(sockfd_, (struct sockaddr *) &serv_addr_, sizeof(serv_addr_));
	FD_ZERO(&writefds);
	FD_SET(sockfd_, &writefds);
	timeout.tv_sec = 10;
	timeout.tv_usec = 0;
	select(sockfd_ + 1, NULL, &writefds, NULL, &timeout);
	unsigned int flag_len;
	getsockopt(sockfd_, SOL_SOCKET, SO_ERROR, &flag_, &flag_len);
	if (flag_ < 0) {
		print_fatal("Error connecting to RT port 30003");
		return false;
	}
	sockaddr_in name;
	socklen_t namelen = sizeof(name);
	int err = getsockname(sockfd_, (sockaddr*) &name, &namelen);
	if (err < 0) {
		print_fatal("Could not get local IP");
		close(sockfd_);
		return false;
	}
	char str[18];
	inet_ntop(AF_INET, &name.sin_addr, str, 18);
	local_ip_ = str;
	comThread_ = std::thread(&UrRealtimeCommunication::run, this);
	return true;
}

void UrRealtimeCommunication::halt() {
	keepalive_ = false;
	comThread_.join();
}

void UrRealtimeCommunication::addCommandToQueue(std::string inp) {
	int bytes_written;
	if (inp.back() != '\n') {
		inp.append("\n");
	}
	if (connected_)
		bytes_written = write(sockfd_, inp.c_str(), inp.length());
	else
		print_error("Could not send command \"" +inp + "\". The robot is not connected! Command is discarded" );
}

void UrRealtimeCommunication::setSpeed(double q0, double q1, double q2,
		double q3, double q4, double q5, double acc) {
	char cmd[1024];
	sprintf(cmd,
			"speedj([%1.5f, %1.5f, %1.5f, %1.5f, %1.5f, %1.5f], %f, 0.02)\n",
			q0, q1, q2, q3, q4, q5, acc);
	addCommandToQueue((std::string) (cmd));
	if (q0 != 0. or q1 != 0. or q2 != 0. or q3 != 0. or q4 != 0. or q5 != 0.) {
		//If a joint speed is set, make sure we stop it again after some time if the user doesn't
		safety_count_ = 0;
	}
}

void UrRealtimeCommunication::run() {
	uint8_t buf[2048];
	int bytes_read;
	bzero(buf, 2048);
	struct timeval timeout;
	fd_set readfds;
	FD_ZERO(&readfds);
	FD_SET(sockfd_, &readfds);
	print_debug("Realtime port: Got connection");
	connected_ = true;
	while (keepalive_) {
		while (connected_ && keepalive_) {
			timeout.tv_sec = 0; //do this each loop as selects modifies timeout
			timeout.tv_usec = 500000; // timeout of 0.5 sec
			select(sockfd_ + 1, &readfds, NULL, NULL, &timeout);
			bytes_read = read(sockfd_, buf, 2048);
			if (bytes_read > 0) {
				setsockopt(sockfd_, IPPROTO_TCP, TCP_QUICKACK, (char *) &flag_, 
						sizeof(int));
				robot_state_->unpack(buf);
				if (safety_count_ == safety_count_max_) {
					setSpeed(0., 0., 0., 0., 0., 0.);
				}
				safety_count_ += 1;
			} else {
				connected_ = false;
				close(sockfd_);
			}
		}
		if (keepalive_) {
			//reconnect
			print_warning("Realtime port: No connection. Is controller crashed? Will try to reconnect in 10 seconds...");
			sockfd_ = socket(AF_INET, SOCK_STREAM, 0);
			if (sockfd_ < 0) {
				print_fatal("ERROR opening socket");
			}
			flag_ = 1;
			setsockopt(sockfd_, IPPROTO_TCP, TCP_NODELAY, (char *) &flag_,
					sizeof(int));
			setsockopt(sockfd_, IPPROTO_TCP, TCP_QUICKACK, (char *) &flag_, 
					sizeof(int));
	
			setsockopt(sockfd_, SOL_SOCKET, SO_REUSEADDR, (char *) &flag_,
					sizeof(int));
			fcntl(sockfd_, F_SETFL, O_NONBLOCK);
			while (keepalive_ && !connected_) {
				std::this_thread::sleep_for(std::chrono::seconds(10));
				fd_set writefds;

				connect(sockfd_, (struct sockaddr *) &serv_addr_,
						sizeof(serv_addr_));
				FD_ZERO(&writefds);
				FD_SET(sockfd_, &writefds);
				select(sockfd_ + 1, NULL, &writefds, NULL, NULL);
				unsigned int flag_len;
				getsockopt(sockfd_, SOL_SOCKET, SO_ERROR, &flag_, &flag_len);
				if (flag_ < 0) {
					print_error("Error re-connecting to RT port 30003. Is controller started? Will try to reconnect in 10 seconds...");
				} else {
					connected_ = true;
					print_info("Realtime port: Reconnected");
				}
			}
		}
	}
	setSpeed(0., 0., 0., 0., 0., 0.);
	close(sockfd_);
}

void UrRealtimeCommunication::setSafetyCountMax(uint inp) {
	safety_count_max_ = inp;
}

std::string UrRealtimeCommunication::getLocalIp() {
	return local_ip_;
}