Semi-active shock absorber control system
AssigneeActive Shock, Inc.
InventorsJohn A. LaPlante, William T. Larkins
Life of this patent
Estimating the term…
Abstract
A semi-active control methodology is provided for a spring/mass system, for example a real-time adjustable shock absorber system. The methodology includes defining a plurality of operating zones based on system parameters and user-definable or preset inputs. The methodology also includes processing to account for non-inertial spring/mass system response and multidimensional forces acting on the system, and an acceleration hedge calculation to accurately define system operation at extrema of travel. The methodology is generally directed at producing a plurality of valve control signals, selecting among the valve control signals, and applying the selected control signal to the valve in a closed-loop feedback system to adjust the energy in the spring/mass system.
Claims19
A method for determining if a shock absorber system is compressing and for generating a target control signal for shock absorber system comprising two masses coupled together by a spring and a controllable valve to adjust the energy in said system, said method comprising the steps of:
- determining if said spring mass system is compressing in a z direction by determining the current velocity of said masses with respect to one another;
- generating an inertial endstop signal based on said relative velocity and said relative position of said masses, said inertial endstop signal comprising a signal that is proportional to the minimum acceleration necessary for one of said masses to arrive at a position of minimum travel at approximately zero velocity;
- generating a damped signal based on a spring force constant, said damped signal comprising a signal proportional to a damped trajectory of at least one of said masses;
- generating a comfort signal, said comfort signal defined as an upper force threshold for said critically damped signal;
- and
- selecting one of said signals as a target signal to control said valve and thereby adjust the energy in said spring/mass system.
A method for determining if a shock absorber system is expanding and for generating a target control signal for shock absorber system comprising two masses coupled together by a spring having a controllable valve to adjust the energy in said system, said method comprising the steps of:
- determining if said spring mass system is expanding in a z direction by determining the current velocity of said masses with respect to one another;
- generating an inertial endstop signal based on said relative velocity and the relative position of said masses, said inertial endstop signal comprising a signal that is proportional to the minimum acceleration necessary for one of said masses to arrive at a position of maximum travel at approximately zero velocity;
- generating a damped signal based on a spring force constant, said damped signal comprising a signal proportional to a damped trajectory of at least one of said masses;
- generating a first valve prepositioning signal to bias said valve so that the system anticipates an impulse acceleration that will occur to the system;
- generating a second valve prepositioning signal to bias the valve at approximately the open position to allow the mass to freely move apart within the constraints of the system;
- and
- selecting one of said signals as a target signal to control said valve and thereby adjust the energy in said spring/mass system.
A method for generating a target inertial and non-inertial energy control signal in a spring/mass shock absorber system comprising two masses coupled together by a spring having a controllable valve to adjust the energy in said system, said method comprising the steps of:
- generating an endstop signal based on the relative velocity and relative position of said two masses, said inertial endstop signal comprising a signal that is proportional to the minimum acceleration necessary for one of said masses to arrive at a position of maximum or minimum travel at approximately zero velocity;
- modifying said endstop signal with a signal indicative of the absolute velocity and the absolute displacement of said masses with respect to one another;
- and
- determining if said endstop signal should be designated as a target control signal for said controllable valve based on the relative velocity of said masses.
A method for generating a target multidimensional damped energy control signal in a spring/mass shock absorber system comprising two masses coupled together by a spring having a controllable valve to adjust the energy in said system, said method comprising the steps of:
- generating a damped signal based on a spring force constant, said damped signal comprising a signal proportional to a damped trajectory of at least one of said masses in the z direction;
- defining a critically damped coefficient;
- multiplying said damped signal by said critically damped coefficient;
- measuring the acceleration of at least one of said two masses in the x and/or y direction;
- and
- modifying said critically damped coefficient based on the measured acceleration of at least one of said two masses in the x and/or y direction;
- and
- determining if said damped signal should be designated as a target control signal for said controllable valve.
A method for generating a target direct valve control signal in a spring/mass shock absorber system comprising two masses coupled together by a spring and a controllable valve to adjust the energy in said system, said method comprising the steps of:
- generating a first valve prepositioning signal to bias said valve so that the system anticipates an impulse acceleration that will occur to the system;
- generating a second valve prepositioning signal to bias the valve at approximately the open position to allow the mass to freely move apart within the constraints of the system;
- and
- selecting between said first or second valve prepositioning signals to be designated as a target control signal for said controllable valve.
A method for modifying a valve control signal with an acceleration hedge control signal in a spring/mass shock absorber system comprising two masses coupled together by a spring having a controllable valve to adjust the energy in said system, said method comprising the steps of:
- generating a plurality of valve control signals based on the relative velocity of said masses;
- generating an acceleration hedge signal proportional to the addition of the acceleration or force of a first one the masses to that of the second one mass to drive the average acceleration or force of the second mass to approximately equal the actual acceleration or force of the first mass;
- and
- adding said acceleration hedge signal to a selected one of said valve control signals.
Dependencies are inferred from the claim text.