Robotic manipulator having at least one spring compensated joint

A robotic manipulator, comprising:

• at least one spring compensated joint, comprising:
• a four-bar linkage including a primary link arranged apart from a secondary link, and a first side link arranged apart from a second side link, the first and second side links coupled between the primary and secondary links at distal ends thereof to define a polygon;
• at least one gravity compensating spring coupled to the polygon, the at least one gravity compensating spring diagonally coupled within the polygon of the four-bar linkage between a first attachment point on the secondary link and a second attachment point on the first side link, the second attachment point positioned diagonally from the first attachment point;
• and
• a spring adjustment assembly coupled to one end of the at least one gravity compensating spring and configured to adjust a position of at least one of the first attachment point or the second attachment point of the at least one gravity compensating spring;
• a sensor configured to measure a force or a torque of a payload coupled to the four-bar linkage;
• and
• a feedback controller configured to use an output of the sensor to alter at least one of the first attachment point or the second attachment point of the at least one gravity compensating spring and dynamically adjust a lifting force in response to the force or torque of the payload.