Аннотация:
This paper is devoted to the design of gravity compensators for prismatic joints. The
proposed compensator depends on the suspension of linear springs together with mechanical
transmission mechanisms to achieve the constant application of force along the sliding span of
the joint. The use of self-locking worm gears ensures the isolation of spring forces. A constant-
force mechanism is proposed to generate counterbalance force along the motion span of the
prismatic joint. The constant-force mechanism is coupled with a pin-slot mechanism to transform
to adjust the spring tension to counterbalance the effect of rotation of the revolute joint. Two
springs were used to counterbalance the gravity torque of the revolute joint. One of the springs
has a moving pin-point that is passively adjusted in proportion with the moving mass of the
prismatic joint. To derive the model of the compensator, a 2-DoF system which consists of
a revolute and a prismatic joint is investigated. In contrast to previous work, the proposed
compensator considers the combined motion of rotation and translation. The obtained results
were tested in simulation based on the dynamic model of the derived system. The simulation
shows the effectiveness of the proposed compensator as it significantly reduces the effort required
by the actuators to support the manipulator against gravity. The derived compensator model
provides the necessary constraints on the design parameters.