Cable tension control device

A cable tension control device, comprising:

• a pair of first active rollers clamping a cable therebetween;
• a first driver driving the first active rollers to rotate so as to convey the cable forward;
• a pair of second active rollers clamping the cable therebetween at an upstream position from the first active rollers;
• a second driver driving the second active rollers to rotate so as to convey the cable forward;
• a floating roller arranged between the first active rollers and the second active rollers and exerting a pushing force on the cable;
• and
• an actuator driving the floating roller to move vertically to adjust the pushing force exerted on the cable, a tension force applied on the cable is controlled to be equal to a predetermined tension force by controlling the pushing force and by controlling a speed difference between a first speed at which the first active rollers convey the cable forward and a second speed at which the second active rollers convey the cable forward.