Method and apparatus for cable-driven adaptive vibration control
First Claim
1. A vibration control drive system used in an unmanned aerial vehicle (UAV), comprising:
- a base platform fixedly coupled to a UAV structure;
a working platform coupled to the base platform by two or more cables at two or more connection points on the working platform;
two or more actuators positioned either on the base platform or the working platform, each actuator configured to receive a signal to adjust tension in a corresponding cable; and
a first controller coupled to and adapted to control the two or more actuators, whereby two or more control signals are calculated for the two or more actuators based on a target position from a current position of the working platform according to one of (i) an open-loop configuration, (ii) a first closed-loop configuration utilizing velocity of the working platform as a feedback signal, or (iii) a second closed-loop configuration utilizing velocity of the working platform as a first feedback signal and the position information of the working platform as a second feedback signal,wherein each of (i) the open-loop, (ii) the first closed loop, and (iii) the second closed loop configurations initially calculates a target pose vector of the working platform, andwherein the target pose vector is calculated based on
l1=[l11 l12 . . . l1n]T, ls=[ls1 ls2 . . . lsn]T, le=[le1 le2 . . . len]T wherebyl1i represents a length of each of the two or more cables and which includes lsi which represents an inelastic portion and lei which represents an elastic portion,ls*=l1*−
le where * denotes a target representation of the working platform, and is calculated based on
M{umlaut over (x)}+C{dot over (x)}+G=−
JTτ
where M represents inertia matrix,C represents Coriolis matrix,G represents gravity matrix,J represents Jacobian matrix, andτ
represents tension in the two or more cables, which yields n−
1 equations for n cable tension unknowns which can be solved for a tension solution, and where tension and the change in le are related based on
τ
=EA·
diag−
1(le)Δ
le, whereE represents Young'"'"'s modulus of elasticity of the elastic portion and A represents cross sectional area of each of the two or more cables, andΔ
le represents extended length of each of the two or more cables and is defined by l1−
ls−
le and
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Accused Products
Abstract
A vibration control system for an unmanned aerial vehicle (UAV) is disclosed. The system includes a base platform fixedly coupled to a UAV structure, a working platform coupled to the base platform by two or more cables at two or more connection points on the working platform, and two or more actuators positioned either on the base platform or the working platform, each actuator configured to receive a signal to adjust tension in a corresponding cable, wherein by adjusting tension in the two or more cables, natural frequency of the working platform can be adjusted in response to frequency of vibration experienced by the working platform in order to maintain a frequency ratio (FR) of the vibration frequency to the natural frequency at or above a predetermined value.
4 Citations
14 Claims
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1. A vibration control drive system used in an unmanned aerial vehicle (UAV), comprising:
-
a base platform fixedly coupled to a UAV structure; a working platform coupled to the base platform by two or more cables at two or more connection points on the working platform; two or more actuators positioned either on the base platform or the working platform, each actuator configured to receive a signal to adjust tension in a corresponding cable; and a first controller coupled to and adapted to control the two or more actuators, whereby two or more control signals are calculated for the two or more actuators based on a target position from a current position of the working platform according to one of (i) an open-loop configuration, (ii) a first closed-loop configuration utilizing velocity of the working platform as a feedback signal, or (iii) a second closed-loop configuration utilizing velocity of the working platform as a first feedback signal and the position information of the working platform as a second feedback signal, wherein each of (i) the open-loop, (ii) the first closed loop, and (iii) the second closed loop configurations initially calculates a target pose vector of the working platform, and wherein the target pose vector is calculated based on
l1=[l11 l12 . . . l1n]T, ls=[ls1 ls2 . . . lsn]T, le=[le1 le2 . . . len]T wherebyl1i represents a length of each of the two or more cables and which includes lsi which represents an inelastic portion and lei which represents an elastic portion, ls*=l1*−
le where * denotes a target representation of the working platform, and is calculated based on
M{umlaut over (x)}+C{dot over (x)}+G=−
JTτwhere M represents inertia matrix, C represents Coriolis matrix, G represents gravity matrix, J represents Jacobian matrix, and τ
represents tension in the two or more cables, which yields n−
1 equations for n cable tension unknowns which can be solved for a tension solution, and where tension and the change in le are related based on
τ
=EA·
diag−
1(le)Δ
le, whereE represents Young'"'"'s modulus of elasticity of the elastic portion and A represents cross sectional area of each of the two or more cables, and Δ
le represents extended length of each of the two or more cables and is defined by l1−
ls−
le and - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
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9. A vibration control system for an unmanned aerial vehicle (UAV), comprising:
-
a base platform fixedly coupled to a UAV structure; a working platform coupled to the base platform by two or more cables at two or more connection points on the working platform; two or more actuators positioned either on the base platform or the working platform, each actuator configured to receive a signal to adjust tension in a corresponding cable; a first controller configured to provide signals to the actuators; and a second controller coupled to and adapted to control the two or more actuators, whereby two or more control signals are calculated for the two or more actuators based on a target position from a current position of the working platform according to one of (i) an open-loop configuration, (ii) a first closed-loop configuration utilizing velocity of the working platform as a feedback signal, or (iii) a second closed-loop configuration utilizing velocity of the working platform as a first feedback signal and the position information of the working platform as a second feedback signal; wherein by adjusting tension in the two or more cables, natural frequency of the working platform can be adjusted in response to frequency of vibration experienced by the working platform in order to maintain a frequency ratio (FR) of the vibration frequency to the natural frequency at or above a predetermined value, wherein each of (i) the open-loop, (ii) the first closed loop, and (iii) the second closed loop configurations initially calculates a target pose vector of the working platform, and wherein the target pose vector is calculated based on
l1=[l11 l12 . . . l1n]T, ls=[ls1 ls2 . . . lsn]T, le=[le1 le2 . . . len]T wherebyl1i represents a length of each of the two or more cables and which includes lsi which represents an inelastic portion and lei which represents an elastic portion, ls*=l1*−
le where * denotes a target representation of the working platform, and is calculated based on
M{umlaut over (x)}+C{dot over (x)}+G=−
JTτwhere M represents inertia matrix, C represents Coriolis matrix, G represents gravity matrix, J represents Jacobian matrix, and τ
represents tension in the two or more cables, which yields n−
1 equations for n cable tension unknowns which can be solved for a tension solution, and where tension and the change in le are related based on
τ
=EA·
diag−
1(le)Δ
le, whereE represents Young'"'"'s modulus of elasticity of the elastic portion and A represents cross sectional area of each of the two or more cables, and Δ
le represents extended length of each of the two or more cables and is defined by l1−
ls−
le and - View Dependent Claims (10, 11, 12, 13, 14)
-
Specification