Articulated joint
AssigneeVrije Universiteit Brussel
InventorRonald Van Ham
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Abstract
The present invention is related to an articulated joint usable in e.g. robotics and rehabilitation, consisting of a first and second body, rotatably connected to each other, and comprising a third body, equally rotatable around a rotation axis, wherein the third body acts as a lever arm. This lever arm is connected via a spring to a pre-tension mechanism, which may be mounted on the second body, while the rotation of the lever arm with respect to the first body is controlled by an actuator. This construction leads to a joint wherein the position can be controlled independently from the compliance of the joint, thereby yielding a mechanism with improved characteristics compared to existing designs.
Claims27
An articulated joint comprising a first body and a second body joined together so that one body is able to perform a pivoting motion with respect to the other body around a pivoting axis, wherein the joint further comprises:
- a third body coupled to the first body such that the third body pivots with respect to the first body at the pivoting axis and defining a lever arm having a point on the third body offset from the pivoting axis;
- an actuator coupled to the first body and to the third body and operable to set an angle between the third body and the first body by pivoting the third body with respect to the pivoting axis of the first body, wherein the actuator can set the angle between the third body and the first body independent of movement of the first body;
- an elastic element, wherein the elastic element is arranged for exerting a force between the point on the third body and a point on the second body offset from the pivoting axis, wherein the elastic element is capable of being pre-tensioned with a varying pre-tension by a pre-tension mechanism, such that the force exerted by the elastic element on the second body is due to an angle between the second body and the third body on the one hand, and to the pre-tension of the elastic element on the other hand;
- and
- the pre-tension mechanism is operable for changing the pre-tension of the elastic element independent of the angle between the first body and the third body by changing an elongation of the elastic element,
- wherein, when the actuator is controlled to pivot the third body with respect to the pivoting axis of the first body, the force exerted by the elastic element between the second body and the third body generates a torque on the second body that moves the second body towards the third body with a compliance that is adaptable by the pre-tension mechanism changing the pre-tension of the elastic element.
An articulated joint comprising a first body and a second body joined together so that one body is able to perform a pivoting motion with respect to the other body around a pivoting axis, wherein the joint further comprises:
- a third body coupled to the first body such that the third body pivots with respect to the first body at the pivoting axis and defining a lever arm having a point on the third body offset from the pivoting axis;
- an actuator coupled to the first body and to the third body and operable to set an angle between the third body and the first body by pivoting the third body with respect to the pivoting axis of the first body, wherein the actuator can set the angle between the third body and the first body independent of movement of the first body;
- an elastic element, wherein the elastic element is arranged for exerting a force between the point on the third body and a point on the second body offset from the pivoting axis;
- and
- a pre-tension mechanism operable to biasing the elastic element in a variable amount, wherein the pre-tension mechanism can change a biasing force of the elastic element independent of the angle between the first body and the third body by changing an elongation of the elastic element, such that the force exerted by the elastic element on the second body is due to an angle between the second body and the third body on the one hand, and to the biasing force of the elastic element on the other hand,
- wherein, when the actuator is controlled to pivot the third body with respect to the pivoting axis of the first body, the force exerted by the elastic element between the second body and the third body generates a torque on the second body that moves the second body towards the third body with a compliance that is adaptable by the pre-tension mechanism changing the biasing force of the elastic element.
Dependencies are inferred from the claim text.