DE102009057047A1 - Active damping system for dynamically adjusting system behavior of spring-damper system of wheel suspension of bicycle, has sensor detecting controlled variable and awakening control module and rechargeable battery - Google Patents

Abstract

The system has a damping unit (1) arranged parallel to a spring element in wheel suspension of a wheel of a vehicle, and comprises electrical capacitors that are filled with fluids of high dielectric constant. A control module comprises a control algorithm and estimates track parameters. Kalman filter or a luenberger observer measures voltage at the damping unit. A control electronic unit (3) is wired on basis of the voltage and energy recovery. A sensor detects a controlled variable e.g. driver movement, and awakens the control module (2) and a rechargeable battery (4).

Description

The present invention relates generally to suspension systems, more particularly to suspension systems with an adjustable damper.

Vehicles with spring-damper systems have been in use for a long time to achieve the objectives of driving safety and ride comfort. Hydraulic shock absorbers have been used for some time in these spring-damper systems for vehicles. In these, the damping force is adjusted via orifices and the viscosity of the hydraulic oil.

From the DE 102 40 568 A1 is known a shock absorption system for two-wheelers, wherein the shock absorption system based on electrorheological and / or magnetorheological fluids is realized. It is usually used a closed piston in which the electrorheological fluid is pressed through a small gap. An applied electric field controls the damping force.

Furthermore, from the DE 10 2006 006 482 A1 regulated active-passive vibration absorption device with energy recovery for two-wheelers known. Here, a plunger coil assembly serves as an energy recovery unit. By means of the electrorheological damper itself, no mechanical energy can be effectively converted into electrical energy and therefore not used to charge the battery. The energy yield from the Tauchspulenanordnung does not meet the requirements when operating, for example, on a mountain bike.

Furthermore, it is not possible with electro-rheological dampers according to the current state of the art to produce damping forces which accelerate the compression or rebound movement of a damped wheel. The set damping force always counteracts the compression or rebound movement.

Another problem with today's design of electrorheological dampers is a mostly existing basic damper characteristic, to which the electrorheological damping force is applied. It is needed for a certain hydraulic gain to achieve higher actuating forces without further design effort. Due to the hydraulic reinforcement, a basic damper constant is also produced in the de-energized case. In order to optimally design a chassis, however, the unstable or boundary-stable, ie undamped, controlled system is required as the controlled system. Only in this way can comfortable response and optimal control behavior be achieved. To create an optimal spring-damper characteristic on the mountain bike, an adjustment of the damper depending on the driver type and the driver's weight up to 1500 N is required. For optimal control, a basic damper constant of almost 0 is required. This is not possible without major design effort according to the current state of the art with electrorheological dampers. In addition, there is the already mentioned above problem that such dampers can not convert even mechanical into electrical energy.

The present invention makes it now the task of introducing a new damper concept, which provides an optimal adjustment and mechanical energy can convert into electrical energy and so ideally supplied itself with the required energy without a required in addition to the actual damper energy recovery unit such. B. a plunger coil as in DE 10 2006 006 482 A1 needed to run. Furthermore, the invention is able to generate positive and negative damper forces, which means that a cushioned wheel can rebound faster than in the undamped case, whereby the traction can be increased enormously. This makes it possible, even larger unsprung masses to follow the course of the soil and thus to allow improved traction when accelerating or braking the vehicle.

In the figures, the invention is shown and explained in more detail with reference to the embodiments illustrated in FIGS.

Show it:

1 : System overview as a block diagram of the components

2 : schematic representation of the arrangement of the damper unit on Voder- and rear fork on the example of a bicycle

3 : Sectional view of the damper unit

4 : simplified basic circuit for controlling the damper unit

In 1 the system overview of the invention is shown. The invention consists of a damper unit 1 , a control module 2 (eg microcontroller) with sensors (not shown) for acceleration and / or speed, a battery 4 and the control electronics 3 for the damper unit.

2 schematically shows a two-wheeler, in which in the front fork 6 one side or right / left one damper unit 1 parallel to the spring element 9 is installed. In the area of the rear wheel between the rear swingarm 8th and frame 5 is another damper unit parallel to the rear spring element 10 installed. The spring element, z. B. as a steel or carbon spring or as Be executed air spring element. The control module 2 and the battery 4 Can be installed inside the suspension fork or outside on the bike. To get a suspension of any vehicle, z. B. bike or car to equip with the new damper concept, must be replaced on the suspension of each wheel of the conventional or the ERF damper against the damper unit according to the invention according to claim 1 and the other system components of the invention are supplemented.

In 3 is the damper unit according to the invention 1 shown in section. The damper unit 1 electrically consists of the parallel connection of several electrical capacitors, which are designed with a dielectric of high dielectric constant. For this purpose, in each case one side of the corresponding capacitor surfaces 11 with the high dielectric 12 coated. For this purpose, z. As a ceramic coating can be used. The coating thickness is in the range of a few mm and depends on the dielectric strength of the material used. The lines from the control electronics 3 to the damper unit 1 as well as the lines inside the damper unit to the individual capacitors are in 3 not shown. These are isolated from each other.

The corresponding capacitor surfaces are now connected to the moving parts of the spring-damper system so that they can move against each other during the compression or rebound and thus cause a change in the total capacity of the damper unit. In the example in 3 the damper unit is round 13 executed, which corresponds to a parallel connection of cylinder capacitors. It is also conceivable, however, any other design that causes a change in the total capacity, z. B. as plate capacitors with a cross 14 as a cross section, or from several slats. Because with this arrangement a gap 15 between the capacitor surfaces, the capacitance would of course be reduced by the low dielectric constant of the ambient air. This gap 15 is therefore filled with a liquid of the highest possible dielectric constant, so that the rebound or rebound movement takes place in an open liquid bath. Since the liquid does not have to be pushed through any gap, as with the ERF dampers, this does not produce a basic damper constant, but even reduces the friction between the capacitor surfaces. Through a sealing system 16 Ensures that no liquid can escape.

It should be emphasized once again that the liquid is not the actual damping task, but only increase the capacity and the minimum friction between the Kodensatorflächen, or a capacitor surface and the ceramic coating 12 to reduce the corresponding capacitor area.

During the compression or rebound of the single wheel, the capacitance of the capacitors changes, since these are structurally arranged so that the capacitance varies between the maximum and the minimum value. If no voltage is applied to the capacitors, then the total damping force is 0. The chassis is not damped. The damping force increases quadratically with the applied voltage. This can go beyond 5 kV, depending on the design to provide the desired damping forces. As a result, the desired adjustability of the damper characteristic is achieved.

The mechanical energy of the disturbance variables is converted into electrical energy when, with the capacitor charged, the total capacitance decreases due to the rebound or rebound operation.

In this case, the charging voltage can be disconnected from the capacitor after charging or continue to be applied. If the charging voltage remains applied, then it is forced that the charge from the capacitor into the battery flows back against the set voltage. This forcing from the discharge of the charge produces the desired damping force and at the same time generates electrical energy therefrom. If the set charging voltage is disconnected after charging, the energy stored in the capacitor increases and then, after re-applying the set voltage to the battery 4 fed back.

If the capacitor system of the damper unit is charged at low capacity and then separated from the charging voltage, so mechanical energy is released when increasing the capacity by compression or rebound. As a result, a damping force is generated which does not counteract the compression or rebound velocity, but reinforces it. This ensures that the wheel can either spring faster or rebound, resulting in the benefits of traction.

In the 4 simplified shown control electronics according to the invention 3 must now be such that they are those of the parent control module 2 (eg PID control algorithm) voltage applied in the event that the damping force of the compression or rebound movement is to be directed opposite, as described above, when the capacity is reduced by compression or rebound movements, and in the case in that the capacity is increased by compression or rebound movements separating the power supply from the damper unit so that the charge does not flow back into capacity below the set voltage can, otherwise half of the effluent heat dissipated in heat in the supply lines and so could not be used. The reconnection of the voltage must be done so that the energy is stored to the greatest possible extent in the capacitor and does not dissipate into heat in the supply lines. Only by this type of wiring, the mechanical energy remaining in the battery can be stored and operation is guaranteed almost without an additional charging of the battery by the user.

Now by the parent control module 2 (For example, PID control algorithm) requested a manipulated variable, so that the damping force to increase the input or rebound movement and thus act in their direction to z. B. to allow high traction, the control electronics of the invention must 3 in the event that the capacity is reduced by compression or rebound movements, the voltage from the damper unit 1 and, in the event that the capacity is increased by compression or rebounding, quickly charge and then disconnect the damper unit's capacitor system so that mechanical energy can be released and the desired force is translated.

The damper unit can be operated with DC or AC voltage. The following is in 4 an example of a control electronics 3 listed. The DC voltage of the battery 4 is via one of the control module 2 controlled switch unit 17 with a duty cycle, which adjusts the height of the manipulated variable, primary side of a transformer 18 placed. On the secondary side there is a low pass consisting of a coil 19 and the damper unit 1 , which electrically corresponds to a capacitor with a parallel resistor. The resistance is not shown in the drawing because it does not show any major effect on the operation of the circuit. Between coil 19 and damper unit 1 is a switching system 20 arranged, which the damper unit 1 can disconnect from the rest of the circuit and the coil output can switch so that the coil is alone in the secondary circuit. The switching system can be constructed from known circuit breakers and diodes. The switching system 20 is from the control module 2 driven. The control module 2 measures the voltage at the damper unit via capacitive voltage dividers 1 or depending on the switching state on the coil 19 and thus evaluates whether the rebound or rebound motion of the wheel causes an increase or decrease in the total capacity of the condenser system of the damper unit.

Depending on the control algorithm required by the control algorithm (eg PID), the control module controls 2 now the switching systems 17 and 20 at. The disconnection of the voltage source can also be done via the switch for setting the duty cycle in the primary circuit of the transformer by suitably setting the parameters of the control module 2 stored control algorithm (eg PID, state controller) can now be given almost any system behavior of the spring-damper system. Using a Kalman filter or Luenberger observer sensors can be saved and the system sizes such as accelerations or speeds are calculated. The method of parameter estimation allows the system parameters to be estimated while the vehicle is in motion and the controller parameters to be tracked to the line parameters to ensure a constant system behavior even under changing conditions, eg shifting the driver's center of gravity in two-wheeled vehicles.

It can be regulated to different sizes, such. Acceleration or velocity, either unsprung mass or sprung mass, or their difference. The nominal value can be specified as 0. If one now sets up the transfer functions of the controlled system, z. B. from soil excitation to body acceleration, so z. For example, with a simple PI controller, a change in the transmission behavior of PDT2 to PT2 or PT2s. If one observes the frequency response of the transfer functions, one recognizes that with the regulated system with increase of the damping one does not reduce the comfort with collisions so much as with the conventional uncontrolled system. You can therefore tune the suspension comfortably, without causing a annoying noticeable ringing.

The energy management of the control module 2 is designed so that it shuts off as soon as the acceleration sensor for an applicable time no longer exceeds an applicable value in terms of amount. The piezoelectric sensor wakes up the control module as soon as a disturbance is applied to the system. Through this strategy and the feeding of converted mechanical energy from the disturbances can be achieved that the battery very rarely or with regular use of the vehicle ideally no longer needs to be charged. Thereby, and by providing positive as well as negative damping forces, as well as an optimal damper characteristic for regulation, there are many new possibilities in the field of two-wheeled vehicles as well as in the automotive sector and there especially with regard to electric vehicles. With the present invention, the range of electric vehicles can be increased, since the energy from the damped road bumps can be returned to the battery.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10240568 A1 [0003]
• DE 102006006482 A1 [0004, 0007]

Claims (1)

An active damping system for dynamically adapting the system behavior of the spring-damper system to a wheel suspension and for energy recovery, comprising a damper unit arranged in the wheel suspension of each wheel of a vehicle parallel to the spring element (US Pat. 1 ), consisting of electrical capacitors, which can be filled with a liquid of the highest possible dielectric constant and their damping force generated by the total capacity of the damper unit is changed by the rebound or rebound, which can be done by moving the capacitor surfaces or the dielectric, further comprising a control electronics ( 3 ), which ensures that the damping force can act both in the direction of the buckling or rebound movement and counteracts and ensures that electrical energy from the disturbances converted and back into the battery ( 4 ), further comprising a control module ( 2 ), which contains the control algorithm and the parameter estimation of the line parameters, as well as a Kalman filter or Luenberger observer measures the voltage at the damper unit and the control electronics connected in terms of requested manipulated variable and energy recovery, further comprising sensors for detecting the controlled variable and for waking the control module ( 2 ) and a battery ( 4 ).

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