Controlling Ski Vibration - Method and Apparatus

• US 20150151186A1
• Filed: 12/03/2013
• Published: 06/04/2015
• Est. Priority Date: 12/03/2013
• Status: Active Grant

• Current Assignee: IPCOMM LLC
• Original Assignee: IPCOMM LLC
• Inventors: Czaja, Stanislaw
• Granted Patent: US 9,522,319 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A63C 2203/18 Measuring a physical parameter, e.g. speed, distance
• CPC Class Codes: A63C 2203/22 Radio waves emitting or receiving, e.g. remote control, RFID
• CPC Class Codes: A63C 2203/24 Processing or storing data, e.g. with electronic chip
• CPC Class Codes: A63C 5/075 Vibration dampers vibration dampers per se F16F7/00

Abstract

A method and apparatus for damping of ski vibration consisting of an accelerometer embedded in the ski in communication with the vibration analysis and control system residing in the user smart-phone and actuators attached to the ski. After analysis and classification of vibration frequencies a corrective signal is generated and applied to the actuators providing dampening force.

Claims

1. A system for controlling ski or snowboard vibration comprising:

a MEMS accelerometer attached to the ski providing measurements of ski vibration;

a smart-phone based vibration analyzer and control system designed to cancel such vibrations;

an actuator assembly consisting of at least single MEMS actuator for transferring control signals generated by the smart-phone based control system into a vibration dampening force; and

a radio interface for transferring measurements and control signals between the sensor, a smart-phone based vibration control system and an actuator(s),

wherein the vibration analyzer provides frequency domain estimation of ski vibration from the acceleration vectors received form the accelerometer; and

wherein after such estimation is obtained, the vibration control performs;

a) classification of vibration frequencies into natural, bending and torsional frequencies categories;

b) selection of fundamental bending and torsional frequencies with amplitudes above the predefined threshold level;

c) generation of an inverse matrix of such selected vibration frequencies;

and wherein, after modification of such matrix by the equipment calibration information and the user information, generates control signal with a frequency and gain identical to ski vibration but with opposite amplitude transmits such control signals the thermo-electrical MEMS actuators embedded in the ski producing reactive force canceling ski vibration.

2. The method of claim 1, wherein the accelerometer embedded into the ski and providing measurements of acceleration vectors with several degrees of freedom communicates such measurements to the smart-phone based vibration analyzer using Personal Area Network radio interface.

3. The method of claim 1, wherein the actuator assembly, consisting one or several MEMS actuators capable of producing displacement at the frequency and force required to cancel ski vibration

4. The method of claim 3, wherein said actuator assembly is attached, or embedded in the ski equipment.

5. The method of claim 1, wherein the analysis of ski vibration consists of estimation of ski vibration frequencies by performing frequency analysis of the time domain acceleration vectors;

classification of vibration frequencies into fundamental and harmonics frequencies and discarding of all harmonics frequencies.

6. The method of claim 1, wherein during such vibration analysis, the retained Fundamental frequencies are further classified into one of three categories:

a) natural bending frequencies;

b) vibration bending frequencies;

c) torsional bending frequencies.

7. The method of claim 1, wherein during such vibration analysis all natural bending frequencies are discarded, while all bending and torsional frequencies with the amplitudes above their respective destructive thresholds levels are retained.

8. The method of claim 7, wherein the retained frequencies matrix is converted to time domain, scaled by:

the equipment calibration information; and

the user information, and then presented as a reference signal to the control loop generating control signals for the actuators.

9. The method of claim 8, wherein such control signal is transmitted to the actuators causing the thermo-electrical MEMS structure to expand and/or contract with the frequency equal to ski vibration but inverse in amplitude.

10. The method of claim 1, wherein the equipment calibration information consist of:

a ski or snowboard design parameters, which among the others includes such information as;

total length, effective length, turning radius, logitudal and torsional stiffness; and

a ski calibration parameters, which among the others includes such information as;

natural deflection due to standard load, natural vibration frequencies and their amplitudes, and vibration damping coefficient.

11. The method of claim 1, wherein the user information consist of:

the user physical characteristics, such as;

weight, height, etc;

the user skiing level, for example—

beginner, advanced, and ski response preference parameters, for example—

soft, racing, etc.; and

the slope snow conditions, for example—

hard, ice, powder.

12. The method of claim 10, wherein the ski natural deflection of the ski is obtained by placing the ski on support located at ¼

distance from each end of the ski effective length and applying a load of N₁ [kg] to the point located at ½

of the ski effective length, then recording the ski center deflection; and

wherein, the natural deflection of the ski tip is obtained by placing the support of at the ½

point of the ski effective length and another at the tip-end of the ski effective length, then applying a standard load of N₂ [kg] at the ½

distance between the ½

point of the ski effective length and the tip-end of the ski effective length, then recording deflection of ski tip section.

13. The method of claim 10, wherein the center ski natural vibration frequencies and their amplitudes is obtained by placing the ski on support located at ¼

distance from each end of the ski effective length, then applying and instantaneously releasing load of N₁ [kg] to the point located at ½

of the ski effective length, while recording ski center vibration frequencies and amplitudes; and

wherein, the ski tip natural vibration frequencies and their amplitude is obtained by placing the support of at the ½

point of the ski effective length and another at the tip-end of the ski effective length, then applying and instantaneously releasing load of N₂ [kg] at the ½

distance between the ½

point of the ski effective length and the tip-end of the ski effective length, while recording ski tip vibration frequencies and amplitudes.

14. An apparatus to control ski vibration consisting of:

a multi-axes accelerometer attached to the ski providing measurements of magnitude and direction of acceleration of the ski;

means for wirelessly receiving magnitude and direction of the acceleration from an accelerometer;

means providing estimation of ski vibration frequencies and their amplitudes;

means for generation of a control signals intended to cancel ski vibration;

means for wirelessly transmitting control signals to the actuators attached to the ski equipment; and

an actuator subsystem consisting of a single or multiplicity of thermo-electrical actuators,

wherein, the acceleration vectors received from an accelerometer are translated to the frequency domain, and after extraction of the fundamental vibration frequencies and selection of the vibration frequencies with amplitudes above the predefined threshold level, convert such vibration frequencies to the time domain, and scaling such time domain function by the ski calibration and the user information, then applying such scaled function to the control loop as a reference for the generation of a control signals intended to cancel ski vibration; and

wherein upon reception of such control signals, the thermo-electrical actuators provides linear expansion does producing force to the extension cores of the actuators assembly which cancels ski vibration.

15. The method of claim 14, wherein the number and orientation of actuator/extension core assemblies inside the actuator subsystem may be logitudal for canceling only the bending vibrations or longitudinal and transversal, or longitudinal and transversal, or any combination thereof, for simultaneous cancellation of both the bending and the torsional vibrations.

16. The method of claim 14, wherein the actuator subsystem is attached to the ski or embedded into the ski core.

17. The method of claim 14, wherein the ski vibration damping coefficient is scaled by the ski calibration information and the user information before it is applied as a reference to produce the vibration control signal.

18. A computer accessible memory medium for storing program instruction of the ski vibration control system, wherein the program instructions execute all of the following:

retrieve magnitudes and amplitudes of an acceleration vectors from the multi-axes accelerometer using short-range wireless link;

perform analysis of such acceleration vector in order to estimate ski vibration;

scaling of the residual vibration estimates by the;

first, second and third information, then applying such result as a reference signal for the actuator control loop; and

transmitting the resulting control signal to the actuators,

wherein the first information consist of ski design parameters, wherein the second information consists of ski calibration parameters, and wherein the third information consists of user physical and preference parameters.

19. The memory medium of claim 18, wherein the vibration analysis consists of:

performing of an DFT (Discrete Fourier Transform) of the time domain samples received form a multi-axes accelerometer to estimate vibration frequencies and their respective amplitudes;

retaining all fundamental frequencies while discarding all harmonic frequencies;

storing the bending frequencies, and the torsional frequencies in their respective frequency bins;

applying bending and torsional thresholds to the respective frequency bins and discarding all frequencies with amplitudes falling below the respective thresholds;

adding the remaining frequency matrixes and generate the time domain representation of the result through the IDFT (Inverse Discrete Fourier Transform).

20. The memory medium of 18, wherein the scaled estimates of the is applied as a reference to the control loop generating control signals canceling such residual vibration.