Force sensor for cable actuator
AssigneeCommissariat A L'energie Atomique Et Aux Energies Alternatives
InventorPhilippe Garrec
Life of this patent
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Abstract
An actuator having a nut (4) co-operating with a screw (2); a first cable (6) coupled to the nut and functionally connected to an output (16, 17, 22.4) of the actuator (100); and a motor (3) arranged to drive the screw (2) in rotation. The actuator also has a mechanism (92) for comparing the actual position of the nut relative to the frame (10) with a theoretical position for the nut relative to the frame (10) in order to obtain a position deviation (δang4, δlin4) of the nut; and a mechanism (93) for determining a force applied to the output (22.4) of the cable actuator (100) as a function of the position deviation of the nut. Also disclosed is a method of measuring a force applied to an output (16, 17, 24.1) of an actuator (100), and to a method of determining prior loading (t6,9) of a cable actuator (100).
Claims25
A cable actuator comprising:
- a frame;
- a screw rotatably mounted on the frame and extending along a first axis;
- a nut co-operating with the screw;
- a first cable coupled to the nut and functionally connected to an output of the actuator;
- a second cable coupled to the nut and functionally connected to the output of the actuator;
- and
- a motor arranged to drive the screw in rotation;
- the first cable being arranged to exert forces opposing the nut being driven in rotation by the screw so as to constitute anti-rotation means such that rotation of the screw under drive from the motor causes the nut to move along the screw;
- the cable actuator also comprising:
- means for determining an actual position of the nut relative to the frame;
- means for comparing the actual position of the nut relative to the frame with a theoretical position for the nut relative to the frame in order to obtain a position deviation of the nut;
- and
- means for determining a force applied to the output of the cable actuator as a function of the position deviation of the nut.
A measuring method for measuring a force applied at the output of a cable actuator comprising:
- a frame;
- a screw mounted on the frame and extending along a first axis;
- a nut co-operating with the screw;
- a first cable coupled to the nut and functionally connected to an output of the cable actuator;
- and
- a motor arranged to drive the screw in rotation;
- the first cable being arranged to exert forces opposing the nut being driven in rotation by the screw so as to constitute anti-rotation means such that rotation of the screw under drive from the motor causes the nut to move along the screw;
- the measuring method for measuring a force comprising:
- determining an actual position of the nut relative to the frame;
- comparing the actual position of the nut relative to the frame with a theoretical position for the nut relative to the frame in order to obtain a position deviation of the nut;
- and
- determining a force applied to the output of the cable actuator as a function of the position deviation of the nut.
A method of determining prior loading of a cable actuator comprising:
- a frame;
- a screw mounted on the frame and extending along a first axis;
- a nut co-operating with the screw;
- a first cable coupled to the nut and functionally connected to the output of the cable actuator;
- and
- a motor arranged to drive the screw in rotation;
- the first cable being arranged to exert forces opposing the nut being driven in rotation by the screw so as to constitute anti-rotation means such that rotation of the screw under drive from the motor causes the nut to move along the screw;
- the method of determining prior loading comprising:
- bringing the nut to a predetermined position relative to the frame;
- holding the output of the cable actuator stationary;
- controlling the motor so that it applies a predetermined torque to the screw;
- determining an actual position of the nut relative to the frame;
- comparing the actual position of the nut relative to the frame with the predetermined position for the nut relative to the frame in order to obtain a position deviation of the nut;
- and
- determining the prior loading acting at least on the first cable as a function of the position deviation of the nut.
Dependencies are inferred from the claim text.