EP0739766A2
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EP
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Method for controlling motion using an adjustable damper
Assignee: Lubrizol Corp
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Filing: 1996-04-25
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Granted: —
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Expires: 2016-04-25
Abstract
Abstract The relative motion and force between two interconnected elements can be controlled by a semi-active damper to minimize the instances of the motion exceeding acceptable limits, while maximizing isolation between the elements. Applying an algorithm to the control parameters of the damper provides excellent isolation from input vibration and shocks. The dampers and control algorithms are useful in primary vehicle suspension systems, cab mounts, seat mounts, and engine mounts.
Inventors
- 👤 Frederick P. Boyle
- 👤 Nicholas K. Petek
- 👤 Dale P. Smith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 11:17
CPC Classifications
B; B60; B60N; B60N2/00; B60N2/50; B60N2/501; B60G; B60G17/00; B60G17/015; B60G17/018; B60G99/00; B60G99/002; B60K; B60K5/00; B60K5/12; B60K5/1208; B60N2/502; B60N2/505; B60N2/52; B60N2/522; B60N2/525; B60G2400/00; B60G2400/10; B60G2400/102; B60G2400/20; B60G2400/206; B60G2400/25; B60G2400/252; B60G2400/90; B60G2400/91
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
320 words
A method for controlling the relative motion between two elements movably interconnected through a linkage which includes a spring assembly which tends to maintain the elements at an equilibrium position, at least the first element thereof being subjected to externally generated motion inputs and tending to transmit a first force in response thereto to the second element thereof; said elements being provided with a means for applying a second, controlled, force therebetween; said method comprising: (a) measuring the displacement x rel of the second element relative to the first element, x rel being defined as zero at the equilibrium position; (b) determining the relative velocity v rel between said first and second elements; (c) calculating a force F applied defined as: F applied = F calc - F sys where F calc is a force, calculated from knowledge of the position and motion of the elements, sufficient to prevent the relative motion of the elements from exceeding predetermined limits, and F sys is a nonzero sum of the forces acting between the first and second elements other than the controlled force applied by the second force means, provided that F applied = 0 if said force F applied is in the same direction as the relative velocity v rel of the elements, or if | v rel | ≤ v db , where v db is a velocity deadband with a preselected value greater than or equal to zero, and F applied = F max if said force F applied is in direction opposite the relative velocity v rel of the elements, and greater than the maximum force F max that can be applied by the second force means in the direction of F applied ; and (d) applying said force F applied between the first and second elements; whereby the force transmitted from the first element to the second element and the relative displacement between said elements are controlled.
Claim 2
Dependent Claim
137 words
The method of claim 1 wherein both the relative velocity v rel and relative acceleration a rel between the elements are calculated values, and wherein F calc = ma rel 1 - 1 + 2a rel d v rel 2 if v rel > 0 and v rel 2 > -2a rel d , F calc = ma rel 1 + 1 + 2a rel d v rel 2 if v rel < 0 and v rel 2 > -2a rel d , provided that F applied = 0 if conditions 1 and 2 are not met; where m is the effective mass of the second element, and d is the distance from the relative displacement to the acceptable extreme displacement limit x +limit or x -limit in the direction of the relative velocity v rel .
Claim 3
Dependent Claim
53 words
The method of claim 1, wherein F calc = - mv rel 2 2d where: m is the effective mass of the second element, d is the distance from the relative displacement to the acceptable extreme displacement limit x +limit or x -limit in the direction of the relative velocity v rel .
Claim 4
Dependent Claim
107 words
The method of claim 1 wherein F calc = - mv rel 2 2d if v rel F sys < 0 , F calc = -2ζv rel km if condition 1 is not met; where: m is the effective mass of the second element, d is the distance from the relative displacement to the acceptable extreme displacement limit x +limit or x -limit in the direction of the relative velocity v rel , k is the spring rate of the spring assembly at the relative displacement x rel , and ζ is a number greater than or equal to 0 and less than or equal to 1.
Claim 5
Dependent Claim
165 words
The method of claim 1 wherein the absolute acceleration of the second element is measured and the relative velocity v rel of the elements and the absolute velocity v abs of the second element are calculated values; and wherein F calc = - mv rel 2 2d if v rel 2 > -4dζv abs k/m or [v rel > 0 and v abs < -F sys 2ζ km ] , or or [v rel < 0 and v abs > -F sys 2ζ km ]} , F calc = -2ζv abs km if condition 1 is not met; where: m is the effective mass of the second element, k is the spring rate of the spring assembly at the relative displacement x rel , d is the distance from the relative displacement to the acceptable extreme displacement limit x +limit or x -limit in the direction of the relative velocity v rel , and ζ is a number greater than 0.5 and less than 3.
Claim 6
Dependent Claim
240 words
The method of claim 1 wherein the absolute acceleration of the second element is measured and the relative velocity v rel of the elements, the relative acceleration a rel of the elements, and the absolute velocity v abs of the second element are calculated values, and wherein: F calc = ma rel 1 - 1 + 2a rel d v rel 2 if v rel > 0 and v rel 2 > -2a rel d and [v abs < -F sys 2ζ km or v rel 2 > 8dkζ 2 v abs 2 ma rel + 4ζv abs km ] F calc = ma rel 1 + 1 + 2a rel d v rel 2 if v rel < 0 and v rel 2 > -2a rel d and [v abs > -F sys 2ζ km or v rel 2 > 8dkζ 2 v abs 2 ma rel + 4ζv abs km ] and condition 1 is not met; F calc = -2ζv abs km if conditions 1 and 2 are not met; where: m is the effective mass of the second element, k is the spring rate of the spring assembly at the relative displacement x rel , d is the distance from the relative displacement to the acceptable extreme displacement limit x +limit or x -limit in the direction of the relative velocity v rel , and ζ is a number greater than 0.5 and less than 3,
Claim 7
Independent Claim
29 words
The method of any of the preceding claims further comprising in step (a) measuring the absolute acceleration of the two elements and calculating the relative acceleration a rel therefrom.
Claim 8
Independent Claim
96 words
The method of any of the preceding claims where F sys is approximated by F sys = -kx'-Cv rel , where x' is the relative displacement of the elements in excess of a displacement deadband x db with a value of zero or greater, such that x' = 0 if | x rel | ≤ x db and x' = X rel - x db sgn(x rel )if |x rel | > x db , k is the spring rate of the spring assembly at the relative displacement x rel , and C is a constant.
Claim 9
Independent Claim
26 words
The method of any of the preceding claims wherein the means for applying a second, controlled, force is a semiactive damper containing a field responsive fluid.
Claim 10
Independent Claim
31 words
The method of any of the preceding claims wherein the first element comprises a vehicle body and the second element comprises an engine, a tractor cab, or a seat, suspended thereon.
Claim 11
Independent Claim
49 words
The method of any of claims 1-9 wherein the second element is a seat and an occupant thereof, and wherein mass m is the portion of the total mass of the seat and the occupant which is supported through said linkage when said seat and occupant are at rest.
Claim 12
Independent Claim
54 words
The method of any of claims 1-9 wherein the first element is a wheel assembly and the second element comprises a vehicle body, and wherein mass m is taken as that portion of the total mass of the vehicle body which is supported by said wheel assembly when said vehicle body is at rest.
Claim 13
Independent Claim
151 words
A device for controlling the relative motion between two elements movably interconnected through a linkage which includes a spring assembly which tends to maintain the elements at an equilibrium position, at least the first element thereof being subjected to externally generated motion inputs and tending to transmit a first force in response thereto to the second element thereof; said elements having extreme limits of acceptable displacement therebetween of x +limit in a positively defined direction and x -limit in a negatively defined direction; said device comprising: (A) an adjustable damper capable of applying a variable force F applied between said first and second elements; and (B) a controller adapted to send a control signal to said damper in response to the condition of the two movably interconnected elements, said control signal corresponding to a value of F applied ; wherein F applied is determined as in any of the claims 1-8.
References Cited (Backward Citations)
No citation records indexed.
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