Human collaborative robot system

A human-collaborative robot system in which a robot and a human share a working space, comprising:

• a first detection unit configured to directly or indirectly detect a first physical quantity which is changed in response to contact force applied to the robot when the robot comes in contact with an external environment;
• a second detection unit configured to directly or indirectly detect a second physical quantity which is changed in response to the contact force applied to the robot when the robot comes in contact with the external environment;
• and
• a stop command unit configured to compare the first physical quantity detected by the first detection unit with a first threshold value, compare the second physical quantity detected by the second detection unit with a third threshold value, stop the robot according to a predetermined stop method when the first physical quantity is equal to or greater than the first threshold value and the second physical quantity is smaller than the third threshold value, and stop the robot in a shorter period of time as compared with the predetermined stop method when the first physical quantity is equal to or greater than the first threshold value and the second physical quantity is equal to or greater than the third threshold value.