Surgical robot arm

A surgical robot arm comprising:

• a main body;
• a first link connected to the main body by a first joint;
• a second link axially coupled to the first link to be rotatable around a second joint with respect to the first link;
• a third link axially coupled to the second link to be rotatable around a third joint with respect to the second link;
• a fourth link axially coupled to the third link to be rotatable around a fourth joint with respect to the third link;
• a fifth link axially coupled to the fourth link to be rotatable around a fifth joint with respect to the fourth link;
• a first driving part that provides driving force to rotate one or more pulleys;
• a second driving part that provides driving force to rotate one or more pulleys;
• a first set of pulleys comprising one or more pulleys that rotate together by a same angle due to rotation of the first driving part;
• and
• a second set of pulleys comprising one or more pulleys that rotate together by a same angle due to rotation of the second driving part,
• wherein, when the first set of pulleys and the second set of pulleys rotate together, the second link and the third link integrally rotate together around the second joint, and,
• when only the second set of pulleys rotate, the third link rotates with respect to the second link around the third joint.