An electromagnetic electric power machine line control brake control system

Abstract

The application discloses an electromagnetic type electronic control brake control system of an electric agricultural machine, which comprises a wheel hub brake disc, an elastic clamp body, an electromagnetic coil, an electromagnet and a brake friction plate; the elastic clamp body comprises elastic cantilevers on the left and right sides for clamping the wheel hub brake disc; the elastic cantilevers on the left and right sides are connected with each other; the electromagnet is installed on the elastic cantilevers on the left and right sides of the elastic clamp body; the electromagnetic coil is installed on the electromagnet; and the brake friction plate is installed on the electromagnet; the elastic deformation of the elastic clamp body is controlled by the electromagnetic coil, so that the elastic cantilevers on the left and right sides of the elastic clamp body are attracted to each other or repelled from each other, so that the wheel hub brake disc is braked or unbraked. The application can increase braking force, reduce braking distance and time, and accurately control power, target speed, braking distance and time, and has a clever structure, good safety, reliability and sensitivity.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electromagnetic drive-by-wire brakes, in particular to an electric agricultural machine electromagnetic drive-by-wire brake control system. BACKGROUND

[0002] The electromagnetic drive-by-wire brake is crucial for intelligent electric agricultural machines, and it is not only an important device for ensuring driving safety, but also can protect crops, improve work efficiency and save energy and protect the environment. At present, the drive-by-wire brake is mainly an electronic hydraulic brake system (EHB), that is, a motor drives a worm gear according to an electric signal, and the worm gear pushes a brake hydraulic cylinder to brake. However, the transmission link is complex, and the reliability, efficiency and cost are not optimal. How to remove the intermediate transmission link to realize direct drive braking of electric energy, simplify the agricultural machine drive-by-wire brake and make it efficient, and at the same time meet the driving braking performance of the agricultural machine is an engineering technical problem to be solved. SUMMARY

[0003] Therefore, the application provides an electric agricultural machine electromagnetic drive-by-wire brake control system, which comprises a hub brake disc, an elastic clamp body, an electromagnetic coil, an electromagnet and a brake friction plate. The elastic clamp body comprises elastic cantilevers on the left and right sides for clamping the hub brake disc, the elastic cantilevers on the left and right sides are connected to each other, the electromagnet is installed on the elastic cantilevers on the left and right sides, the electromagnetic coil is installed on the electromagnet, and the brake friction plate is installed on the electromagnet. The elastic deformation of the elastic clamp body is controlled by the electromagnetic coil, the elastic cantilevers on the left and right sides of the elastic clamp body are attracted to each other or repelled from each other, and the hub brake disc is braked or unbraked.

[0004] In order to realize energy saving and emission reduction, increase the braking force, reduce the braking distance and time, in a further technical solution, a first braking mode is included, in the first braking mode, the elastic clamp body is in a normal release state, the current directions of the electromagnetic coils on the left and right sides of the elastic clamp body are the same, when the left and right electromagnetic coils are powered, the left and right electromagnets generate electromagnetic forces that attract each other, the elastic cantilevers on the left and right sides of the elastic clamp body are attracted to each other, and the elastic clamp body clamps the hub brake disc to realize braking.

[0005] In order to improve the safety of the vehicle, save the parking brake, increase the braking force, reduce the braking distance and time, in a further technical solution, a second braking mode is included, in the second braking mode, the elastic clamp body is in a normal clamping state, the current directions of the electromagnetic coils on the left and right sides of the elastic clamp body are opposite, when the left and right electromagnetic coils are powered, the left and right electromagnets generate electromagnetic forces that repel each other, the elastic cantilevers on the left and right sides of the elastic clamp body are repelled from each other, and the elastic clamp body releases the hub brake disc to realize unbraking.

[0006] In order to prolong the service life of the brake, in a further technical solution, the first brake mode and the second brake mode are included, in the second brake mode, the elastic clamp body is in a normal clamping state, the current directions of the electromagnetic coils located on the left and right sides of the elastic clamp body are opposite, when the left and right electromagnetic coils are powered, the left and right electromagnets generate repulsive electromagnetic force, the elastic cantilevers on the left and right sides of the elastic clamp body repel each other, the elastic clamp body loosens the hub brake disc to release the brake;

[0007] In the first brake mode, the elastic clamp body is in a normal loosening state, the current directions of the electromagnetic coils located on the left and right sides of the elastic clamp body are the same, when the left and right electromagnetic coils are powered, the left and right electromagnets generate attractive electromagnetic force, the elastic cantilevers on the left and right sides of the elastic clamp body attract each other, the elastic clamp body clamps the hub brake disc to brake;

[0008] When the vehicle is used in the second brake mode for a period of time, the brake friction plate is worn, and the elastic clamp body cannot be in a normal clamping state, the first brake mode is switched to.

[0009] In order to accurately control the power and braking distance and time, in a further technical solution, a controller, an electromagnetic driver, a speed sensor, and a current sensor are included; the speed sensor collects the wheel speed and transmits the wheel speed signal to the controller, the current sensor collects the output current signal of the electromagnetic driver and feeds it back to the controller, the controller compares the wheel speed signal with the target speed, receives the output current feedback signal of the electromagnetic driver, and calculates and generates a control voltage according to the braking target speed, and the electromagnetic driver receives the control voltage and outputs current to the electromagnetic coil.

[0010] In order to accurately control the power and braking distance and time, in a further technical solution, the controller compares the wheel speed signal with the target speed, receives the output current feedback signal of the electromagnetic driver, and calculates and generates a control voltage according to the braking time c The relationship is:

[0011]

[0012] Wherein, k i is the current loop proportional control parameter, k p is the speed loop proportional control parameter, k d is the speed loop differential control parameter, k I is the speed loop integral control parameter, r0 is the target speed of the wheel, r s is the output speed of the speed sensor, R is the resistance of the electromagnetic coil, and t is the braking time.

[0013] The output current i(t) of the electromagnetic driver is related to:

[0014]

[0015] where K a is the amplification parameter of the electromagnetic driver, u c is the control voltage, and R is the electromagnetic coil resistance.

[0016] The electromagnetic force F e of the electromagnet on the wheel hub brake disc is given by the expression:

[0017]

[0018] where i(t) is the current through the copper coil, x(t) is the distance between the electromagnet pole and the wheel hub brake disc, C e is the electromagnetic force coefficient.

[0019] The elastic force F k of the elastic clamp is given by the expression:

[0020]

[0021] where E is the elastic modulus of the elastic clamp, l is the equivalent cantilever length of the elastic clamp, I is the bending section coefficient of the elastic clamp, and δ k is the displacement of the elastic clamp under the force.

[0022] The braking force F f is given by the expression:

[0023] F f = μF N

[0024] where μ is the friction coefficient, and F N is the pressure of the brake friction plate on the wheel hub brake disc.

[0025] The pressure F N of the brake friction plate on the wheel hub brake disc is given by the expression:

[0026] F N = F e (i, x) - F k

[0027] The friction torque T f of the brake friction plate on the wheel hub brake disc is given by the expression:

[0028] T f = F f R f

[0029] where R fThe distance from the equivalent action point of the brake friction plate on the hub brake disc to the center of the hub brake disc (brake force action point equivalent radius).

[0030] The electrically driven agricultural machinery electromagnetic steer-by-wire brake control system of the present application has the following advantages over the prior art:

[0031] 1. The elastic deformation of the elastic clamp body controlled by the electromagnetic coil causes the elastic cantilevers on the left and right sides of the elastic clamp body to attract or repel each other, thereby braking or releasing the braking of the hub brake disc. This increases the braking force, reduces the braking distance and time, and provides fast response, high safety and reliability, good sensitivity, a clever structure, and precise control of power and braking distance and time.

[0032] 2. The present application includes two braking modes. In the first braking mode, the left and right electromagnetic coils are not powered during normal driving, thereby reducing power consumption, achieving energy saving and emission reduction, increasing braking force, and reducing braking distance and time. In the second braking mode, the left and right electromagnetic coils are not powered when the vehicle loses power, and the vehicle is in a braking state, thereby improving vehicle safety, eliminating the need for parking brakes, increasing braking force, and reducing braking distance and time. A hybrid mode of the first and second braking modes can also be used. When the vehicle is used in the second braking mode for a period of time and the brake friction plate is worn, the elastic clamp body cannot be in a constant clamping state, and the first braking mode is switched to, so that the vehicle can still be used normally, thereby prolonging the service life of the vehicle braking.

[0033] 3. The controller of the present application compares the wheel speed signal with the target speed, receives the output current feedback signal of the electromagnetic driver, and calculates and generates a control voltage based on the braking target speed. The electromagnetic driver receives the control voltage and outputs current to the electromagnetic coil, thereby achieving precise control of power, speed, braking distance, and time. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve to explain the present application, and do not constitute an improper limitation of the present application. In the drawings:

[0035] Figure 1 is a perspective view of the electrically driven agricultural machinery electromagnetic steer-by-wire brake device of the present application;

[0036] Figure 2 is a front view of Figure 1 ;

[0037] Figure 3 is a schematic diagram of the framework of the electrically driven agricultural machinery electromagnetic steer-by-wire brake control system of the present application;

[0038] Figure 4 is a schematic diagram of the relationship between current and braking torque.

[0039] Figure 5 This is a schematic diagram illustrating the braking effect of the present invention;

[0040] Figure 6 This is a schematic diagram of the braking distance of the present invention. Detailed Implementation

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] like Figure 1 and Figure 2 As shown, the present invention preferably provides an electromagnetic drive-by-wire brake control system for electric agricultural machinery, including a hub brake disc 1, an elastic clamp 2, an electromagnetic coil 3, an electromagnet 4, and brake friction pads 5. The elastic clamp 2 is used to clamp the hub brake disc 1. The elastic clamp 2 has a U-shaped structure and includes elastic cantilever arms 20 on both sides for clamping the hub brake disc 1. The elastic cantilever arms 20 on both sides are connected to form a U-shaped structure. The electromagnet 4 is installed on the elastic cantilever arms 20 on both sides of the elastic clamp 2. The electromagnetic coil 3 is installed on the electromagnet 4. The brake friction pads 5 are installed on the electromagnet 4. The electromagnetic coil 3 controls the elastic deformation of the elastic clamp 2, causing the elastic cantilever arms 20 on both sides of the elastic clamp 2 to attract or repel each other, thereby braking or releasing the hub brake disc 1.

[0043] The braking system includes a first braking mode. In this mode, the elastic clamp 2 is in a normally open state. The current in the electromagnetic coils 3 on both sides of the elastic clamp 2 is in the same direction. When the left and right electromagnetic coils 3 are energized, the two electromagnets 4 generate an electromagnetic force that attracts each other, causing the elastic cantilever arms 20 on both sides of the elastic clamp 2 to attract each other. The elastic clamp 2 then clamps the wheel hub brake disc 1 to achieve braking. When the left and right electromagnetic coils 3 are de-energized, the elastic clamp 2 is in a normally open state, i.e., the braking is released.

[0044] The system includes a second braking mode. In this mode, the elastic clamp 2 is in a normally clamped state. The currents in the electromagnetic coils 3 on the left and right sides of the elastic clamp 2 are in opposite directions. When the left and right electromagnetic coils 3 are energized, the two electromagnets 3 generate a repulsive electromagnetic force, causing the elastic cantilever arms 20 on the left and right sides of the elastic clamp 2 to repel each other. This releases the brakes from the wheel hub brake disc 1. When the left and right electromagnetic coils 3 are not energized, the elastic clamp 2 is in a normally clamped state, i.e., the braking state. Compared to the first braking mode, the second braking mode offers better safety and reliability, and a faster response time.

[0045] When the vehicle is used in the second brake mode for a period of time, the brake friction plate 5 is worn, and the elastic clip body 2 cannot be in the always-clamped state, the first brake mode is switched to. The mixed mode is adopted, the switching is simple, and only the current direction of the left and right electromagnetic coils 3 needs to be changed to realize the switching of the first brake mode and the second brake mode. Since the brake device is a consumable, in the case that the second brake mode fails, the first brake mode can be switched to, and the service life of the brake can be prolonged.

[0046] As shown in Figure 3 , it includes a controller, an electromagnetic driver, a rotation speed sensor, and a current sensor; the rotation speed sensor collects the wheel rotation speed and transmits the wheel rotation speed signal to the controller, the current sensor collects the output current signal of the electromagnetic driver and feeds it back to the controller, the controller compares the wheel rotation speed signal with the target speed, receives the output current feedback signal of the electromagnetic driver, calculates and generates the control voltage according to the brake time, and the electromagnetic driver receives the control voltage and outputs the current to the electromagnetic coil 3. The power and the braking distance and time are precisely controlled.

[0047] The controller compares the wheel rotation speed signal with the target speed, receives the output current feedback signal of the electromagnetic driver, calculates and generates the control voltage u c , according to the brake time.

[0048]

[0049] , wherein k i is a current loop proportional control parameter, k p is a rotation speed loop proportional control parameter, k d is a rotation speed loop differential control parameter, k I is a rotation speed loop integral control parameter, r0 is the target rotation speed of the wheel, r s is the output rotation speed of the rotation speed sensor, and R is the resistance of the electromagnetic coil.

[0050] The output current i(t) of the electromagnetic driver is related to the control voltage u c , and the resistance R of the electromagnetic coil (3).

[0051]

[0052] , wherein K a is the amplification parameter of the electromagnetic driver, u c is the control voltage, and R is the resistance of the electromagnetic coil (3).

[0053] The electromagnetic force F e (i,x) of the electromagnet 4 on the hub brake disc 1 is related to the control voltage u c and the resistance R of the electromagnetic coil (3).

[0054]

[0055] Where i(t) is the current through the copper coil, x(t) is the distance between the electromagnet pole and the hub brake disc, C e is the electromagnetic force coefficient;

[0056] C e The expression is

[0057]

[0058] Where S is the pole area, N is the number of turns of the electromagnet copper coil, and μ0 is the vacuum permeability.

[0059] The elastic clamp body 2 elastic force F k The expression is:

[0060]

[0061] Where E is the elastic modulus of the elastic clamp body 2, l is the equivalent cantilever length of the elastic clamp body 2, I is the bending resistance section modulus of the elastic clamp body 2, and δ k is the displacement of the elastic clamp body under the force.

[0062] The bending resistance section modulus I expression is:

[0063]

[0064] Where y is the neutral axis of the elastic clamp body 2, and A is the differential area.

[0065] The braking force expression is:

[0066] F f = μF N

[0067] Where F f is the friction force of the brake pad 5 on the hub brake disc 1, μ is the friction coefficient, and F N is the pressure of the brake pad 5 on the hub brake disc 1.

[0068] The pressure F N of the brake pad 5 on the hub brake disc 1 is expressed as:

[0069] F N = F e (i, x) - F k

[0070] The frictional resistance torque T f of the brake pad 5 on the hub brake disc 1 is expressed as:

[0071] T f = F f R f

[0072] Among them, R f It is the distance between the equivalent point of application of the brake friction pad on the wheel hub brake disc and the center of the wheel hub brake disc (equivalent radius of the braking force application point).

[0073] like Figure 4 As shown, in the first braking mode, the curve of the relationship between current and braking torque of the electromagnetic brake-by-wire system for electric agricultural machinery is mainly divided into two stages. The current range for the entire stage is 0-3.57A, which is the stage where the electromagnet 4 overcomes the elastic force of the elastic clamp 2. At this time, the pressure of the brake friction pad 5 on the wheel hub brake disc 1 is zero. In the later stage, the current is greater than 3.57A. At this time, the electromagnetic attraction is greater than the elastic force of the elastic clamp 2, the pressure of the brake friction pad 5 on the wheel hub brake disc 1 is greater than zero, and the braking torque increases with the increase of current.

[0074] like Figure 5 As shown, in the first braking mode, the braking effect curve of the electromagnetic brake-by-wire of the electric agricultural machinery is shown. The machinery has a mass of 1000 kg, an initial speed of 30 km / h, and the speed decreases to 0 at 1.16 s.

[0075] like Figure 6 As shown, in the first braking mode, the braking distance curve of the electromagnetic brake-by-wire system for electric agricultural machinery is as follows: the machinery mass is 1000kg, the initial speed is 30km / h, and the braking distance is 4.63m.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electromagnetic drive-by-wire brake control system for electric agricultural machinery, characterized in that, The application relates to a wheel hub brake disc (1), an elastic clamp body (2), an electromagnetic coil (3), an electromagnet (4) and a brake friction plate (5); the elastic clamp body (2) comprises left and right elastic cantilevers (20) used for clamping the wheel hub brake disc (1); the left and right elastic cantilevers (20) are connected with each other; the electromagnet (4) is arranged on the left and right elastic cantilevers (20) of the elastic clamp body (2); the electromagnetic coil (3) is arranged on the electromagnet (4); and the brake friction plate (5) is arranged on the electromagnet (4); the electromagnetic coil (3) controls the elastic deformation of the elastic clamp body (2), the left and right elastic cantilevers (20) of the elastic clamp body (2) are attracted to each other or repelled from each other, the wheel hub brake disc (1) is braked or released from braking.

2. The electromagnetic drive-by-wire brake control system of claim 1, wherein, The application comprises a first braking mode; in the first braking mode, the elastic clamp body (2) is in a normal release state, the current directions of the electromagnetic coils (3) located on the left and right sides of the elastic clamp body (2) are the same, the left and right electromagnets (4) generate mutual attraction electromagnetic force when the left and right electromagnetic coils (3) are electrified, the left and right elastic cantilevers (20) of the elastic clamp body (2) are attracted to each other, the elastic clamp body (2) clamps the wheel hub brake disc (1) to realize braking.

3. The electromagnetic drive-by-wire brake control system of claim 1, wherein, The application comprises a second braking mode; in the second braking mode, the elastic clamp body (2) is in a normal clamping state, the current directions of the electromagnetic coils (3) located on the left and right sides of the elastic clamp body (2) are opposite, the left and right electromagnets (4) generate mutual repulsion electromagnetic force when the left and right electromagnetic coils (3) are electrified, the left and right elastic cantilevers (20) of the elastic clamp body (2) are repelled from each other, the elastic clamp body (2) releases the wheel hub brake disc (1) to realize release from braking.

4. The electromagnetic drive-by-wire brake control system of claim 1, wherein, The application comprises the first braking mode and the second braking mode; in the second braking mode, the elastic clamp body (2) is in a normal clamping state, the current directions of the electromagnetic coils (3) located on the left and right sides of the elastic clamp body (2) are opposite, the left and right electromagnets (4) generate mutual repulsion electromagnetic force when the left and right electromagnetic coils (3) are electrified, the left and right elastic cantilevers (20) of the elastic clamp body (2) are repelled from each other, the elastic clamp body (2) releases the wheel hub brake disc (1) to realize release from braking. In the first braking mode, the elastic clamp body (2) is in a normal release state, the current directions of the electromagnetic coils (3) located on the left and right sides of the elastic clamp body (2) are the same, the left and right electromagnets (4) generate mutual attraction electromagnetic force when the left and right electromagnetic coils (3) are electrified, the left and right elastic cantilevers (20) of the elastic clamp body (2) are attracted to each other, the elastic clamp body (2) clamps the wheel hub brake disc (1) to realize braking. When the brake friction plate (5) is worn after the vehicle is used in the second braking mode for a period of time, the elastic clamp body (2) cannot be in the normal clamping state, and the first braking mode is switched to.

5. The electromagnetic drive-by-wire brake control system of any one of claims 1 to 4, wherein, Including controller, electromagnetic driver, rotation speed sensor, current sensor; The rotation speed sensor collects the wheel rotation speed, and transmits the wheel rotation speed signal to the controller, the current sensor collects the output current signal of the electromagnetic driver and feeds back to the controller, the controller compares the wheel rotation speed signal with the target speed, receives the output current feedback signal of the electromagnetic driver at the same time, and calculates and generates the control voltage according to the braking target speed, after the electromagnetic driver receives the control voltage, the output current is output to the electromagnetic coil (3).

6. The electromagnetic drive-by-wire brake control system of claim 5, wherein, The controller compares the wheel rotational speed signal with the target speed, receives the output current feedback signal of the electromagnetic driver, and calculates and generates the control signal according to the braking time The voltage relationship is: wherein, is a current loop proportional control parameter, is a speed loop proportional control parameter, is a speed loop differential control parameter, is a speed loop integral control parameter, is a target speed of the wheel, is a speed of the output of the speed sensor, R is a resistance of the electromagnetic coil, and t is a braking time. Output of the electromagnetic drive The current relationship is: wherein is the amplification parameter of the electromagnetic drive, is the control voltage, R is the resistance of the electromagnetic coil (3); Electromagnetic force of attraction or repulsion of the electromagnet (4) on the wheel hub brake disc (1) The expression is: wherein, is the current through the copper coil, is the distance between the electromagnet pole and the wheel hub brake disc, is the electromagnetic force coefficient; Elastic clip body (2) elastic force Expression is: wherein is the modulus of elasticity of the elastic clip (2), is the equivalent cantilever length of the elastic clip (2), is the flexural section modulus of the elastic clip (2), is the displacement of the elastic clip (2) resulting from the deformation under the force; The braking force expression is: wherein, is the friction force of the brake friction plate (5) against the wheel hub brake disc (1), is the friction coefficient, is the pressure of the brake friction plate (5) against the wheel hub brake disc (1); The pressure of the brake friction plate (5) on the wheel hub brake disc (1) The expression is: Friction torque of brake friction plate (5) against wheel hub brake disc (1) The expression is: wherein is the distance of the equivalent point of action of the brake friction plate on the hub brake disc (1) from the center of the hub brake disc (1).

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