JP2010241401A - Shock absorber in combination with active control capable of coping with vertical impact and control method used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a dilemma that a part of characteristics (for example, shock relieving characteristic) are improved and the other characteristics (for example, dynamic load bearing or statistic load bearing) are lost which is caused by changing natural frequency and damping coefficient ratio that are most important characteristic parameters in a shock absorber configured of passive elements. <P>SOLUTION: Active control by an actuator 9 is combined with a passive system shock absorber and by a method for directly applying action of an inverse phase to response after impact before reaching limit acceleration, the sacrifice of the other characteristics are suppressed as much as possible so that the shock relieving characteristics are improved at a pin point. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a shock absorber in a land transportation vehicle constituted by a spring, a damper, or the like. The present invention also relates to control for improving the impact relaxation characteristics in the vertical direction by using an active control element such as an electric actuator together. Note that the maximum response acceleration is applied as an index for quantitatively evaluating the impact relaxation characteristics.

  Among conventional land transportation vehicles, the evaluation of the transportation environment by a truck or train equipped with an air suspension is high (Non-patent Document 1). The reason why the air suspension is superior is that the natural frequency is low (several Hz), and that the air suspension system maintains the equilibrium height regardless of the weight of the load because the pressure is variable. The former is a basic characteristic that is necessary for shielding external vibrations and shocks, and the latter is a characteristic that is necessary for securing a braking distance against a large shock that occurs when passing through a step or rail joint. One.

  The concept of “actively controlling the characteristics of the shock absorber” also exists in the above-described air suspension system. However, it monitors the vibration environment in real time while driving and feeds back if there is a possibility of resonance, and optimally controls the natural frequency by adjusting the air pressure (natural frequency control for steady vibration). . Therefore, non-stationary and instantaneous impacts are not assumed. When impact is a problem, even an air suspension needs to be handled as one of passive elements whose natural frequency is not controlled.

  The index “maximum response acceleration” is applied to the “impact response spectrum” in the JIS standard (Non-patent Document 1), and can be said to be an appropriate index for quantitatively evaluating the impact relaxation characteristics. If the natural period (order of several hundred ms) of the shock absorber is sufficiently long with respect to the impact action (order of several ms to 10 ms), the maximum response acceleration can be expressed by the following mathematical formula.

Formula 1

    Maximum response acceleration = tc ・ ωo ・ R (ζ)

  In the above formula, tc is a time constant determined by the shock waveform and the like, regardless of the characteristics of the shock absorber. ωo is the natural angular frequency (= natural frequency × 2π). R (ζ) is a function of the damping coefficient ratio ζ and has ζ dependence as shown in the following figure.

Chart 1

  In the above chart, the horizontal axis represents the damping coefficient ratio ζ, and the vertical axis represents R representing ζ dependency.

JIS Standard JIS C 60721-3-2 “Classification of Environmental Conditions and Classification of Environmental Parameters and Severity-Transportation Conditions”

  The natural frequency and damping coefficient ratio are the most important characteristic parameters in a shock absorber composed of passive elements. Changing the parameter value improves some characteristics (eg, impact relaxation characteristics), but other characteristics ( (Example: dynamic or static load bearing) may diminish.

It is assumed that active control by an actuator is used in combination with a shock absorber composed of passive elements to suppress the deterioration of other characteristics as much as possible and to improve impact mitigation characteristics. The control flow of the active control is shown in the following (a) to (2). The numbers in parentheses correspond to the numbers in the drawing.
(A) In a state where there is no impact input, since the acceleration sensor (12) on the input side and the acceleration switch (13) on the output side do not detect acceleration exceeding the specified value, the action of the actuator (9) is in a standby state.
(B) When an impact exceeding a specified level is input from the outside, first, the input-side acceleration sensor (12) sends data to the control unit (computer). Based on the sent data, the control unit calculates the required action force and action start time T2 of the actuator (9).
(C) After the acceleration sensor (12) detects, an impact is transmitted via the spring (1) or the like, and the acceleration switch (13) also detects the specified acceleration. At this time, the actuator (9) is also switched on and the actuator action starts. In addition, the amount of action of the actuator (9) is controlled so that the response acceleration (specified value) at the start of action becomes the maximum response acceleration.
(2) Stop the actuator action at a timing (response speed zero, near response displacement zero, etc.) that passes the peak of the response acceleration and does not leave as much response as possible, such as jumping or residual vibration If stopping at this timing is insufficient, a nonlinear damper with high compatibility with the impact relaxation characteristics is also applied.

  As an effect of the invention, a comparison of impact response when the active control is used together and when the active control is not used is shown below.

Chart 2

  (1) in the above chart is an example of a time schedule of actuator output (action acceleration). The solid lines in (2), (3), and (4) in the above chart are the acceleration response, speed response, and displacement response to which the active control is applied. The broken lines (2), (3), and (4) indicate the response (a damped oscillation of ζ = 0.15) unique to the passive shock absorber that does not apply the active control. The arrow shown in (2) indicates the maximum response acceleration, and it can be seen that although the response acceleration increases or decreases due to the actuator action, it stops rising around the response acceleration at the start of the actuator action. Further, in (2), (3), and (4), when the solid line and the broken line are compared, it can be seen that the solid line has faster attenuation. This is due to timing control for stopping the actuator operation.

  As an effect of the present invention, a comparison of impact response when the active control and the nonlinear damper are applied and when not applied is shown below.

Chart 3

  (1) in the above chart is an example of a time schedule of actuator output (action acceleration). The solid lines in (2), (3), and (4) in the above chart indicate the active control and nonlinear damper (ζ = 0.15 when the response speed is negative, ζ = 0.5 when the response speed is positive). Applied acceleration response, velocity response, displacement response. The broken lines (2), (3), and (4) indicate the response (a damped oscillation of ζ = 0.15) unique to the passive shock absorber that does not apply the active control. The arrow shown in (2) indicates the maximum response acceleration, and it can be seen that the response acceleration takes a certain value for a while from the start of the actuator operation and does not increase. Further, in (2), (3), and (4), when the solid line and the broken line are compared, it can be seen that the solid line has faster attenuation. This is due to the effect of the nonlinear damper.

  As a summary of the effects of the present invention, the effect of reducing the maximum response acceleration by using the active control together with the dependence on the damping coefficient ratio is shown in the following figure.

Chart 4

  In the above figure, the solid line shows the ζ dependence of the maximum response acceleration inherent in the passive shock absorber (Chart 1). □, ◯, and Δ are obtained by setting the actuator action start time T2 to 1/10 natural period, 1/20 natural period, and 1/30 natural period, respectively, in the active control. The broken line is a boundary line (theoretical curve) with a region that is absolutely impossible even when active control is used together. From this figure, it can be seen that the combined use of the active control can significantly reduce the maximum response acceleration in a region where ζ is small.

(Example 1) which is a conceptual diagram which uses together active control, such as an actuator and an acceleration sensor, with the buffer device comprised by passive elements, such as the conventional spring and a damper. It is explanatory drawing regarding the towed vehicle of a unicycle type as one Example of the buffer device of an active control combined use type. The example which applied the compression spring as a buffer spring and has arrange | positioned the electromagnetic motor on the buffer spring (Example 2). It is explanatory drawing regarding the towed vehicle of a two-wheeled vehicle type as one Example of the buffer device of an active control combined use type. The example which applied the compression spring as a buffer spring and arrange | positioned the electromagnetic motor under the buffer spring is illustrated (Example 3). It is explanatory drawing regarding the towed vehicle of a two-wheeled vehicle type as one Example of the buffer device of an active control combined use type. An example in which a tension spring is applied as a buffer spring and an electromagnetic motor is disposed under the buffer spring (Example 3). It is explanatory drawing regarding the towed vehicle of a two-wheeled vehicle type as one Example of the buffer device of an active control combined use type. An example in which an air spring is applied as a buffer spring and an electromagnetic motor is disposed under the buffer spring (Example 3). It is explanatory drawing regarding the towed vehicle of a two-wheeled vehicle type as one Example of the buffer device of an active control combined use type. The example which applied the air spring with an auxiliary tank as a buffer spring, and has arrange | positioned the electromagnetic motor under the buffer spring (Example 3). It is explanatory drawing regarding the towed vehicle of a two-wheeled vehicle type as one Example of the buffer device of an active control combined use type. The example which applied the compression spring as a buffer spring and has arrange | positioned the electromagnetic motor on the buffer spring (Example 3). It is explanatory drawing regarding the towed vehicle of a two-wheeled vehicle type as one Example of the buffer device of an active control combined use type. An example in which an air spring is applied as a buffer spring and an electromagnetic motor is disposed on the buffer spring (Example 3). It is explanatory drawing regarding the towed vehicle of a two-wheeled vehicle type as one Example of the buffer device of an active control combined use type. The example which applied the air spring with an auxiliary tank as a buffer spring, and has arrange | positioned the electromagnetic motor on the buffer spring (Example 3). (Example 4) which is explanatory drawing which shows the structure of a nonlinear oil damper. (Example 4) which is an additional drawing regarding a nonlinear oil damper. (Example 4) which is an additional drawing regarding a nonlinear oil damper. (Example 5) which is explanatory drawing which shows the structure of a nonlinear air damper. (Example 5) which is an additional drawing regarding a non-linear air damper. (Example 5) which is an additional drawing regarding a non-linear air damper. (Example 6) which is a figure regarding a non-linear electromagnetic damper.

  FIG. 1 is a conceptual diagram of a shock absorber according to the present invention, and 1-3, 9, 12-14 are the same as FIG.

FIG. 2 is a plan view, a side view, and a sectional view of one embodiment of a towed vehicle to which the shock absorber according to the present invention is applied. A present Example is a unicycle type, 1-4, 6-14 are the same as that of FIGS.
Reference numeral 5 denotes a unicycle towing structure.

  3 to 9 are a plan view, a side view, and a sectional view of one embodiment of a towed vehicle to which a control method and a buffer system according to the present invention are applied. A present Example is a two-wheeled vehicle type, and 2-4, 6-13, and 15 are common in FIGS. 3 and 7, 1 is a compression spring, and 14 is an oil damper. In FIG. 4, 14 is an oil damper, 16 is a tension spring and its supporting structure. 5 and 8, 14 is an oil damper, and 17 is an air spring (large). 6 and 9, 18 is an air spring (small), 19 is an air damper, and 20 is an auxiliary tank. The basic buffer control mechanism is the same as that of the above-described unicycle type (Example 2).

  10, 11 and 12 are cross-sectional views showing the structure of the nonlinear oil damper according to the present invention. 21 is a piston rod, 22 is a cylinder, 23 is an asymmetric orifice, and 24 is a movable spring.

  FIGS. 13, 14, and 15 are cross-sectional views showing the structure of a nonlinear air damper according to the present invention. Reference numeral 23 denotes an asymmetric orifice, reference numeral 24 denotes a movable spring, and reference numeral 25 denotes a pipe leading to an auxiliary tank.

  FIG. 16 is an external view of an electromagnetic damper. As a function, there is a torque regulation function for preventing the wire 10 from sagging, and an electromagnetic braking function for generating a reverse torque proportional to the rotational speed of the shaft 26 by electromagnetic induction. In addition, in this invention, the case where it can be used as an electromagnetic motor is also included.

  For improving the characteristics of shock absorbers for conventional land transport vehicles or towed light vehicles.

  For shock absorbers for vehicles that will be equipped with solar panels in the future or towed light vehicles.

DESCRIPTION OF SYMBOLS 1 Compression spring 2 Loading platform structure 3 Spring loading table structure 4 Wheel 5 Traction structure 6 Joint part hook (or bearing) between a loading platform and a towing vehicle
7 Joint hook (or bearing) between tow structure (or torsion bar) and tow truck
8 Balance weight 9 Electromagnetic motor (actuator)
10 Wire and turnbuckle 11 Pulley 12 Accelerometer (speed change sensor)
13 Acceleration switch 14 Oil damper 15 Torsion bar 16 Tension spring and support structure 17 Air spring (large)
18 Air spring (small)
19 Air Damper 20 Auxiliary Tank 21 Piston Rod 22 Cylinder 23 Asymmetric Orifice 24 Movable Spring 25 Piping 26 Shaft

Claims (5)

  A shock absorber that is also used in conjunction with active control consisting of an electric actuator, an acceleration sensor, etc., to mitigate vertical impacts in land transport vehicles.   A control method relating to a shock absorber using the active control according to claim 1 together. A method to determine actuator output, etc., from the detected amount of the sensor on the side close to the external environment. A mechanism that outputs an actuator by applying inputs from both sensors above and below the spring to an AND gate. The following three conditions of the actuator output waveform applied in the control method according to claim 2.
(B) Actuator output starts when response acceleration reaches specified value (b) Actuator output that controls response acceleration so that response acceleration at start of actuator output (ie specified value) becomes maximum response acceleration (c) Bounce or residual Actuator output stops at the timing when vibration does not remain as much as possible (response speed zero, response displacement near zero)   A tension transmission mechanism and a nonlinear damper mechanism using a wire cable compatible with the actuator output waveform (one-way action) of claim 3.   A style of a towed vehicle equipped with an electric motor to which claims 1 to 4 are applied. And the style of a towed vehicle with a spring regardless of whether an electric motor is installed.

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