Multijoint manipulator and endoscope system having the same

A multijoint manipulator apparatus comprising:

• a tubular member which includes joints;
• linear motion transmission members inserted in the tubular member, one end of each of the linear motion transmission members being fixed to vicinity of one of the joints;
• a drive unit which longitudinally moves the linear motion transmission members to flex the tubular member, the other end of each of the linear motion transmission members being fixed to the drive unit;
• a position detector which detects positions of the linear motion transmission members moved by the drive unit;
• a tension detector which detects tension applied to the linear motion transmission members;
• an operation unit to which a desired position and a desired posture of a point of interest of the tubular member or a member attached to the tubular member are input;
• and
• a movement degree calculation unit, wherein the movement degree calculation unit
• calculates a current position and a current posture of the point of interest from the positions of the linear motion transmission members detected by the position detector,
• calculates a weighting factor based on the tension detected by the tension detector, the weighting factor serving to give priority to and move the linear motion transmission members the tension of which is relatively low among the linear motion transmission members,
• calculates, based on the weighting factor, movement degrees of the linear motion transmission members to move the point of interest from the calculated current position and the calculated current posture to the desired position and the desired posture, and
• causes the drive unit to pull the linear motion transmission members based on the movement degrees.