KR100534712B1 - Pedal simulator for brake by wire system using mr damper and two-stage-stiffness spring - Google Patents

Abstract

The present invention relates to an electric brake pedal simulator capable of reducing energy consumption by reducing power consumption required to form the same pedal reaction force and reducing a volume of a driver, the pedal receiving a driver's braking input; A rotation angle sensor for measuring a rotation angle of the pedal; An elastic portion for coupling at least one or more springs in series using a stroke limiter; A magnetic rheology damper for forming a damping force using the magnetic rheology fluid; Analyze the signal input from the rotation angle sensor to calculate the rotation angle and rotation angular velocity of the pedal, determine the reference pedal reaction force through the calculated value, the dissipation torque of the magnetic rheological damper to implement the reference pedal reaction force A controller configured to determine a magnetoresistive damper driving current to generate a damping control signal, and to perform a pedal reaction force control operation to adjust a damping force of the magnetic rheological damper; And a current regulator driven according to an input of a damping control signal supplied from the controller to supply a current required for driving the magnetic rheological damper to the magnetic rheological damper.

Description

Pedal simulator for electric brakes {PEDAL SIMULATOR FOR BRAKE BY WIRE SYSTEM USING MR DAMPER AND TWO-STAGE-STIFFNESS SPRING}

The present invention relates to a pedal simulator for an electric brake.

Typically, the Brake-By-Wire (BBW) has no mechanical connection between the driver and the braking wheels, and an electric caliper located at each wheel receives input from a control unit (BBW ECU) and transmits the electric caliper to each wheel. Brakes the vehicle by grasping the disk in position.

With reference to FIG. 1, the main structure of an electric brake apparatus is demonstrated.

First, the pedal simulator receives the driver's braking input (pedal rotation angle) and transmits it to the control unit BBW ECU, and transmits a reaction force to the driver through the pedal.

In addition, the electric caliper is located on each wheel and generates a braking force by grasping the disc with an electric motor according to a signal of a controller (BBW ECU).

The controller (BBW ECU) receives the driver's braking input from the pedal simulator to control the driving of the electric motor of the electric caliper.

The pedal simulator, which is one of the subsystems of the electric brake apparatus as described above, transmits the driver's braking input (pedal rotation angle) to the control unit BBW ECU as an interface unit between the vehicle and the driver.

In addition, since the electric brake device does not have a mechanical connection between the driver and the brake wheel, the pedal impedance is very small during braking, thereby controlling the pedal simulator to assist the driver in the braking operation by transmitting an appropriate pedal reaction force to the driver. Should be performed.

That is, the pedal simulator is a device that transmits a reaction force to the driver, and is a representative haptic device that has a small impedance (system dynamic resistance value) and generally performs an impedance display (force feedback control).

Until now, in order to provide reaction force to the brake pedal, a device using a spring, a permanent magnet, or a hydraulic actuator has been proposed.

However, the existing devices have a limitation in forming reaction force through the pedal due to the characteristics of the actuator.

In other words, when the pedal reaction force is obtained using only the spring, which is a passive element, only the reaction force determined by the spring elasticity can be obtained with respect to the pedal displacement of the system, thereby generating a reaction force appropriate for the braking situation (ie, the reference pedal reaction force). It is impossible to achieve the hysteresis of the pedal reaction, which contributes to reducing driver fatigue in turning or sustained braking situations.

In addition, in the case of using the hydraulic actuator, despite the complexity of the system, there is a problem that the range of reaction force that can be controlled is small and the reaction time is slow.

Accordingly, an object of the present invention is to provide an electric brake pedal simulator that can reduce energy consumption by reducing the power consumption required to form the same pedal reaction force and reduce the volume of the driver.

The present invention for achieving the above object is a pedal for receiving a driver's braking input; A rotation angle sensor for measuring a rotation angle of the pedal; An elastic portion for coupling at least one or more springs in series using two stroke limiters; It is configured between the pedal arm and the vehicle body, and constitutes a partition wall inside the cylinder housing to divide the interior into an inner chamber and an outer chamber filled with the magnetic rheological fluid and connect the fluid passages at the upper and lower portions, and the piston is disposed in the inner chamber and the piston A magnetic rheological damper connected to the rod and having a winding disposed at one side of the lower fluid passage of the partition to form a magnetic field; Analyze the signal input from the rotation angle sensor to calculate the rotation angle and rotational angular velocity of the pedal, determine the reference pedal reaction force through the calculated value, and forms the damping force of the magnetic rheological damper to implement the reference pedal reaction force A controller configured to determine a magnetic rheological damper driving current, generate a damping control signal corresponding thereto, and perform a pedal reaction force control operation to adjust a damping force of the magnetic rheological damper; In the pedal simulator for electric brake including a current regulator which is driven in accordance with the input of the damping control signal supplied from the control unit for supplying a current required to drive the magnetic rheostat damper, the elastic portion outside the cylinder housing A first spring mounted on the piston rod; A second spring installed on the piston rod in series with the first spring and having a weaker rigidity than the first spring; And a stroke limiter disposed on the piston rod to support both ends of the second spring to limit the maximum stroke of the second spring to change the stiffness of the system.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. While many specific details, such as the following description and the annexed drawings, are shown to provide a more general understanding of the invention, these specific details are illustrated for the purpose of explanation of the invention and are not meant to limit the invention thereto. And a detailed description of known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

2 and 3 will be described the configuration of the electric brake pedal simulator according to an embodiment of the present invention.

According to the embodiment of the present invention, as shown in FIG. Control unit for controlling the pedal reaction force by adjusting the damping force of the magnetic rheological damper 20 to form a damping force by using a magneto-Rheological Damper, the elastic portion 43 constituting a plurality of springs, and the magnetic rheological damper 20 ( 100).

2 and 3, the magnetic rheological damper 20 and the elastic portion 43 are coupled in series. That is, the magnetic rheological damper 20 has a straight shape, and the body joint connection joint bracket 27 fixed to the lower end of the cylinder housing 22 and the damper rotation joint bracket 13 fixed to the vehicle body are rotated joints. The inside of the cylinder housing 22 is divided into an inner chamber 24 and an outer chamber 33 filled with the magnetic fluid, and connected to upper and lower fluid passages 23 and 32. A partition wall 45 is formed, and the piston 21 is disposed in the inner chamber 24 to be connected to the piston rod 44, and the lower fluid passage of the partition wall 45 serves as a damping force forming section 32. A winding 26 is formed at one side to form a magnetic field. In addition, a sealing ring 25 is interposed between the cylinder housing 22 and the piston rod 44 to maintain a gas tightness, and the pedal rotation angle displacement. Compression direction stopper 50 and tension direction stop for limiting The fur 51 is mounted on the piston rod 44 on the magnetic rheological damper 20 from the outside and the inside of the cylinder housing 22, respectively, and the pedal arm 14 connecting the pedal 10 has its tip. The pedal rotation joint bracket 11 fixed to the vehicle body is connected to the rotary joint and is rotatable, and a pedal rotation angle sensor 60 is attached to one side thereof.

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The magnetic rheological damper 20 and the pedal arm 14 are fixed to the rotary joint bracket 28 for pedal connection fixed to the piston rod 44 connected to the piston 21 and to one side of the pedal arm 14. It is connected to the joint bracket 12 and the rotary joint for connecting the magnetic rheological damper to rotate.

Elastic portion 43 according to an embodiment of the present invention is composed of a two-stage stiffness spring (Two-Stage-Stiffness Spring) consisting of a compression coil spring having two different stiffness.

That is, the elastic portion 43 is connected in series with the first spring 40, the first spring 40, which is composed of a stiff spring (stiff spring) and has a weaker rigidity than the first spring 40 ( And a second spring 41 composed of a soft spring, and two stroke limiters 42 for changing the rigidity of the system by limiting the maximum stroke of the second spring 41. It is fitted onto the piston rod 44.

That is, the magnetic rheological damper 20 and the elastic portion 43 are coupled as shown in FIGS. 2 and 3.

That is, one end of the first spring 40 is supported by the cylinder housing 22, and the other end is supported by the lower stroke limiter 42.

In addition, both ends of the second spring 41 are interposed between the two stroke limiters 42 supported by the rotating joint inter-spring mounting bracket 29 fixed to the tip of the piston rod 44.

That is, the first and second springs 40 and 41 are disposed in series with each other, and the first and second springs 40 and 41 and the magnetic rheological damper 20 are also disposed in series on a coaxial line.

In addition, the two stroke limiters 42 are also mounted on the piston rod 44 while supporting both ends of the second spring 41 between the rotary joint spring mounting bracket 29 and the first spring 40. Is installed.

This embodiment of the present invention implements a pedal simulator by connecting a magnetic rheological damper 20 using a magnetic rheological fluid and an elastic part 43 having a two-stage stiffness in series, so that the disadvantages of existing systems using electromagnets or springs are used. The present invention relates to a device capable of freely setting the magnitude of reaction force and transmitting a smooth pedal reaction force to the driver.

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That is, when the driver operates the pedal, the pedal reaction force is transmitted to the driver by controlling the damping force of the magnetic rheological damper 20.

When the haptic system such as the embodiment of the present invention is implemented by the magnetic rheological damper 20 only, the only energy source that enters the system is the operator, and the magnetic rheological damper 20 dissipates energy of the system and puts energy into the system. There is a restriction that cannot be given.

This makes the restoring of the pedal impossible because the passive constraint, i.e., the range of pedal reaction force, is limited in the opposite direction to the rotational angular velocity of the drive shaft.

In order to solve this problem, the energy stored in the pedal 43 is stored in the elastic part 43 when the driver brakes using the elastic part 43 which is an energy storage material, and is used for the restoration control.

In particular, since the rigidity of the spring can be adjusted by using the elastic portion 43 having two-stage rigidity, the pedal reaction force control region is widened.

This is particularly the case where the pedal's rotational angular velocity is zero (0) or negative (-part where constant pedal play is maintained, or slowly, as shown in FIGS. 4A and 4B with the driver's foot on the pedal). Pedal pedal release) provides improved pedal reaction.

This will be described in detail below.

2nd spring constant: K ₁

1st spring constant: K ₂

Maximum stroke of damper shaft according to pedal rotation: L _max

2nd spring stroke limit: S _max

Pedal Stroke: x

Let's say

Until the second spring 41 reaches the stroke limiter 42, the equivalent spring constant of the two springs becomes smaller than the spring constant of the second spring 41 due to the series connection of the springs.

,

However, when the spring is compressed and the second spring 41 reaches its maximum stroke (the stroke of the damper shaft ), The equivalent spring constant becomes K ₂ and the reaction force by the spring becomes

,

,

As a result, the reaction force control region of the present system is widened as shown in FIG. 4B, and appropriate hysteresis can be realized through the shaping of the reaction force control region.

By using the technical principle of the elastic portion 43, the overall operation of the electric brake pedal simulator according to the embodiment of the present invention shown in Figs.

First, when the driver applies the braking pressure through the pedal 10, the rotation angle sensor 60 outputs the rotation angle and the rotational angular velocity of the pedal to the controller 100.

At this time, the controller 100 determines the reference pedal reaction force to be followed by the system based on the above information (the pedal rotation angle, the rotational angular velocity, etc.), and then uses the magnetic rheological damper for implementing the reference pedal reaction force ( Determine the damping force of 20).

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Subsequently, the controller 100 determines a driving current to be supplied to the magnetic rheological damper 20 to form a damping force of the magnetic rheological damper 20, and transmits a control signal corresponding thereto to the current regulator 200.

The current regulator 200 supplies a current required to drive the magnetic rheological damper 20 to the magnetic rheological damper 20 based on the control signal.

That is, the process of forming the damping force of the magnetic rheology damper 20 using the magnetic rheology fluid will be described briefly as follows.

Based on a control signal (voltage signal) output from the controller 100, a current is supplied to the winding 26 of the magnetic rheological damper 20 using the current regulator 200 to pass through the damping force forming section 32. A magnetic field 31 is formed around the magnetic rheological fluid.

That is, FIG. 3 is a cross-sectional view of the magnetic rheological damper 20 using the magnetic rheological fluid according to the embodiment of the present invention. In order for the piston 21 to linearly reciprocate along the piston center axis 30, the piston 21 is The repelling magnetorheological fluid must pass through the damping force forming section 32.

At this time, the magnetic field 31 is subjected to the resistance of the magnetic rheological fluid hardened as a solid to form a damping force.

Here, the damping force is formed in proportion to the strength of the magnetic field 31 by the property of the magnetic rheological fluid, the magnetic field 31 is adjusted by the strength of the current flowing through the winding 26.

As described above, in the exemplary embodiment of the present invention, the magnetic type damper 20 may be used to obtain a gain due to the characteristics of the driver type.

That is, the power consumption required to form the same reaction force can be reduced to reduce the energy, and the volume of the driver can be reduced to expect the cost reduction effect.

It also provides an alternative in layout between the driver types.

For example, in the case of the rotary type, it is easy to secure the space under the pedal, and in the case of the straight type, the space of the pedal hinge part is easy.

Exemplary embodiments of the present invention are a pedal-type reaction device, and a typical application field is a pedal simulator for an electric brake device (BBW; Brake-By-Wire System), a pedal reaction device (acceleration / deceleration pedal) of a vehicle simulator (Driving Simulator), It is expected to be applied to many applications that provide reaction force to the operator, such as the reaction force pedal of an indoor driving range and the reaction force pedal of a game machine.

As described above, the electric pedal simulator for electric brake according to the present invention can overcome the limitation of the reaction force generated in the reaction force device using only passive elements such as a spring through the magnetic rheological damper using the property of the magnetic rheological fluid.

In addition, it is possible to control the return of the brake pedal by controlling the restoring force of the spring and the damping force of the magnetic rheological damper.

In addition, it is possible to implement the hysteresis of the pedal reaction force that contributes to reducing the fatigue of the driver in the turning situation or the continuous braking situation through the reaction force control using the magnetic rheological damper.

In addition, by using a spring having two-stage stiffness, the pedal reaction force control region is widened by appropriately adjusting the stiffness of the coil.

In addition, since the driver type is configured as a linear magnetic rheological damper, the power consumption required to form the same reaction force is reduced, thereby reducing the energy consumption, and reducing the volume of the driver, thereby reducing the cost.

1 is a conceptual diagram of a brake by wire system.

2 is a view showing the configuration of a pedal pedal for electric brake according to an embodiment of the present invention.

3 is a view showing the configuration of a magnetic rheological damper according to an embodiment of the present invention.

4A and 4B illustrate a pedal reaction force control region according to an embodiment of the present invention.

Claims (10)

delete delete A pedal configured to receive a driver's braking input; A rotation angle sensor for measuring a rotation angle of the pedal; An elastic portion for coupling at least one or more springs in series using two stroke limiters; It is configured between the pedal arm and the vehicle body, and constitutes a partition wall inside the cylinder housing to divide the interior into an inner chamber and an outer chamber filled with the magnetic rheological fluid and connect the fluid passages at the upper and lower portions, and the piston is disposed in the inner chamber and the piston A magnetic rheological damper connected to the rod and having a winding disposed at one side of the lower fluid passage of the partition to form a magnetic field; Analyze the signal input from the rotation angle sensor to calculate the rotation angle and rotational angular velocity of the pedal, determine the reference pedal reaction force through the calculated value, and forms the damping force of the magnetic rheological damper to implement the reference pedal reaction force A controller configured to determine a magnetic rheological damper driving current, generate a damping control signal corresponding thereto, and perform a pedal reaction force control operation to adjust a damping force of the magnetic rheological damper; In the pedal simulator for electric brake including a current regulator is driven in accordance with the input of the damping control signal supplied from the control unit for supplying a current required for driving the magnetic rheological damper to the magnetic rheological damper, The elastic portion A first spring mounted on an outer piston rod of the cylinder housing; A second spring installed on the piston rod in series with the first spring and having a weaker rigidity than the first spring; And a stroke limiter arranged on the piston rod to support both ends of the second spring to limit the maximum stroke of the second spring to change the stiffness of the system. The method of claim 3, One end of the first spring is supported by the cylinder housing, the other end is supported by one side of the stroke limiter, and the second spring is between the stroke limiters supported by the rotating joint spring mounting bracket, both ends of which are fixed to the piston rod tip. Electric brake pedal simulator, characterized in that supported by. delete The method of claim 3, And the elastic portion and the magnetic rheological damper are configured in series coupling on a coaxial line. delete delete delete The method of claim 3, The piston rod is a pedal simulator for electric brakes, characterized in that the compression direction stopper for limiting the pedal rotation angle displacement, and the tension direction stopper is installed on the outside and inside of the cylinder housing, respectively.