Sensor apparatus and robot system having the sensor apparatus

A robot system comprising:

• a robot;
• a tool guidable by the robot;
• and
• a sensor system between the robot and the tool, wherein:
• the sensor system includes:
• a main body;
• a counter body that is movable relative to the main body;
• a plurality of sensor devices;
• and
• a processor configured to determine a relative position, with respect to three translational directions and three rotational degrees of freedom, between the counter body and the main body from sensor signals output by the sensor devices;
• and
• with respect to each of the plurality of sensor devices, the respective sensor device includes a respective target area on one of the main and counter bodies and a respective sensor, that is configured to detect the target area, on the other of the main and counter bodies.