Multiaxis counterbalance and positioning system using a spatial linkage
A spatial linkage including an inboard gimbal plate that provides a ground for the spatial linkage, an outboard gimbal plate, and at least three links that couple the outboard gimbal plate to the inboard gimbal plate. Each link has a longitudinal axis and two pivotal couplings disposed at opposite ends of the longitudinal axis. Each link is pivotally coupled to the outboard gimbal plate at a first end of the longitudinal axis and pivotally coupled to the inboard gimbal plate at a second end of the longitudinal axis opposite the first end. The pivotal couplings allow the outboard gimbal plate to move relative to the inboard gimbal plate and preventing relative rotation between the outboard gimbal plate and the inboard gimbal plate. Counterweight is coupled to at least one of the links on the opposite side of the inboard gimbal plate from the outboard gimbal plate.
1. A spatial linkage comprising:
an inboard gimbal plate that provides a ground for the spatial linkage;
an outboard gimbal plate;
at least three links, each link having a longitudinal axis and two pivotal couplings disposed at opposite ends of the longitudinal axis, each link pivotally coupled to the outboard gimbal plate at a first end of the longitudinal axis and pivotally coupled to the inboard gimbal plate at a second end of the longitudinal axis opposite the first end, the pivotal couplings allowing the outboard gimbal plate to move relative to the inboard gimbal plate with two degrees of freedom and keeping the outboard gimbal plate parallel to the inboard gimbal plate;
a load coupled to the outboard gimbal plate; and
a counterweight coupled to at least one of the links on the opposite side of the inboard gimbal plate from the outboard gimbal plate to counterbalance the load regardless of a position of the load with respect to the outboard gimbal plate.
2. The spatial linkage of claim 1 wherein the load is a cantilevered load coupled to the outboard gimbal plate.
3. The spatial linkage of claim 2 wherein the cantilevered load has a movable center of gravity.
4. The spatial linkage of claim 1 further comprising:
a grounded sliding support coupled to the inboard gimbal plate such that the inboard gimbal plate is movable laterally along the length of the sliding support and is constrained in all other lateral directions and rotations.
5. The spatial linkage of claim 4 wherein the sliding support includes a counterbalance that maintains the position of the spatial linkage on the sliding support.
6. The spatial linkage of claim 1 further comprising a brake coupled to at least one pivotal coupling such that the brake can be engaged to prevent the outboard gimbal plate from moving relative to the inboard gimbal plate.
7. The spatial linkage of claim 1 wherein the distance between the first end and the second end of the longitudinal axis of each link is adjustable such that the distance remains equal for each of the links.
8. A setup joint system for a robotic arm, the setup joint system comprising:
an inboard gimbal plate that provides a ground for the setup joint system;
an outboard gimbal plate that supports the robotic arm;
at least three links, each link having a longitudinal axis and two pivotal couplings disposed at opposite ends of the longitudinal axis, each link pivotally coupled to the outboard gimbal plate at a first end of the longitudinal axis and pivotally coupled to the inboard gimbal plate at a second end of the longitudinal axis opposite the first end, the pivotal couplings allowing the outboard gimbal plate to move relative to the inboard gimbal plate and keeping the outboard gimbal plate parallel to the inboard gimbal plate; and
a counterweight coupled to at least one of the links on the opposite side of the inboard gimbal plate from the outboard gimbal plate to counterbalance the robotic arm regardless of a position of the robotic arm with respect to the outboard gimbal plate.
9. The setup joint system of claim 8 wherein the outboard gimbal plate supports the robotic arm as a cantilevered load coupled to the outboard gimbal plate.
10. The setup joint system of claim 9 wherein the robotic arm has a movable center of gravity.
11. The setup joint system of claim 8 further comprising:
a grounded sliding support coupled to the inboard gimbal plate such that the inboard gimbal plate is movable laterally along the length of the sliding support and is constrained in all other lateral directions and rotations.
12. The setup joint system of claim 11 wherein the grounded sliding support includes a counterbalance that maintains the position of the spatial linkage on the sliding support.
13. The setup joint system of claim 8 further comprising a brake coupled to at least one pivotal coupling such that the brake can be engaged to prevent the outboard gimbal plate from moving relative to the inboard gimbal plate and hold the robotic arm in a fixed position.
14. The setup joint system of claim 8 wherein the distance between the first end and the second end of the longitudinal axis of each link is adjustable such that the distance remains equal for each of the links.
15. A method of supporting a robotic arm that provides freedom of motion for setting a position of the robotic arm, the method comprising:
supporting the robotic arm with an outboard gimbal plate;
providing a ground support for the robotic arm with an inboard gimbal plate;
coupling the outboard gimbal plate to the inboard gimbal plate with at least three links, each link having a longitudinal axis and two pivotal couplings disposed at opposite ends of the longitudinal axis, each link pivotally coupled to the outboard gimbal plate at a first end of the longitudinal axis and pivotally coupled to the inboard gimbal plate at a second end of the longitudinal axis opposite the first end, the pivotal couplings allowing the outboard gimbal plate to move relative to the inboard gimbal plate and keeping the outboard gimbal plate parallel to the inboard gimbal plate; and
substantially balancing the robotic arm by a counterweight coupled to at least one of the links on the opposite side of the inboard gimbal plate from the outboard gimbal plate to counterbalance the robotic arm regardless of a position of the robotic arm with respect to the outboard gimbal plate.
16. The method of claim 15 further comprising supporting the robotic arm as a cantilevered load coupled the outboard gimbal plate.
17. The method of claim 15 further comprising sliding the inboard gimbal plate on a grounded sliding support such that the inboard gimbal plate is movable laterally along the length of the sliding support and is constrained in all other lateral directions and rotations.
18. The method of claim 15 further comprising maintaining the position of the inboard gimbal plate on the sliding support with a counterbalance on the grounded sliding support.
19. The method of claim 15 further comprising engaging a brake coupled to at least one pivotal coupling to prevent the outboard gimbal plate from moving relative to the inboard gimbal plate and hold the robotic arm in a fixed position.
20. The method of claim 15 further comprising adjusting the distance between the first end and the second end of the longitudinal axis of each link such that the distance remains equal for each of the links.