diff --git a/include/ur_modern_driver/ur_driver.h b/include/ur_modern_driver/ur_driver.h
index d675646..f30d7ff 100644
--- a/include/ur_modern_driver/ur_driver.h
+++ b/include/ur_modern_driver/ur_driver.h
@@ -17,6 +17,7 @@
 #include "ur_realtime_communication.h"
 #include <vector>
 #include <math.h>
+#include <string>
 
 class UrDriver {
 private:
diff --git a/src/ur_driver.cpp b/src/ur_driver.cpp
index 326ce48..f87f139 100644
--- a/src/ur_driver.cpp
+++ b/src/ur_driver.cpp
@@ -75,6 +75,7 @@ void UrDriver::addTraj(std::vector<double> inp_timestamps,
 
 	timestamps.push_back(inp_timestamps[inp_timestamps.size() - 1]);
 	positions.push_back(inp_positions[inp_positions.size() - 1]);
+	/* This is actually faster than using a stringstream :-o */
 	for (unsigned int i = 1; i < timestamps.size(); i++) {
 		char buf[128];
 		sprintf(buf,