Electromagnetic drive-by-wire brake control system of electric agricultural machine

Abstract

The invention discloses an electromagnetic drive-by-wire brake control system of an electric agricultural machine. The electromagnetic drive-by-wire brake control system comprises a hub brake disc, an elastic clamp body, an electromagnetic coil, an electromagnet and a brake friction plate. The elastic clamp body comprises cantilevers which are used for clamping a hub brake disc and have elasticity on the left side and the right side, the cantilevers which have elasticity on the left side and the right side are connected with each other, the electromagnets are installed on the cantilevers which have elasticity on the left side and the right side of the elastic clamp body, the electromagnetic coils are installed on the electromagnets, and the brake friction plates are installed on the electromagnets. The electromagnetic coil controls elastic deformation of the elastic clamp body, so that the elastic cantilevers on the left side and the right side of the elastic clamp body attract each other or repel each other, and the hub brake disc brakes or relieves braking. The braking force is increased, the braking distance and time are reduced, the power, the target speed and the braking distance and time can be accurately controlled, the structure is ingenious, and safety, reliability and sensitivity are good.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic wire-controlled brakes, and in particular to an electromagnetic wire-controlled brake control system for electric agricultural machinery. Background Art

[0002] Electromagnetic wire-controlled brakes are crucial to smart electric agricultural machinery. They are not only an important device to ensure driving safety, but also can protect crops, improve work efficiency, and save energy and protect the environment. At present, wire-controlled brakes are mainly electronic hydraulic brake systems (EHB), that is, the motor drives the worm gear according to the electrical signal, and the worm gear pushes the brake hydraulic cylinder to brake. However, this method has many and complex transmission links, and is not the optimal solution in terms of reliability, efficiency, and cost. How to remove the intermediate transmission link, realize direct-drive braking of electric energy, simplify and efficiently control the wire-controlled brakes of agricultural machinery, and at the same time meet the braking performance of agricultural machinery is an engineering and technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of this, the present invention proposes an electromagnetic wire-controlled brake control system for electric agricultural machinery, comprising a wheel hub brake disc, an elastic clamp, an electromagnetic coil, an electromagnet, and a brake friction pad; the elastic clamp comprises elastic cantilevers on left and right sides for clamping the wheel hub brake disc, the elastic cantilevers on left and right sides are connected to each other, the electromagnet is mounted on the elastic cantilevers on left and right sides of the elastic clamp, an electromagnetic coil is mounted on the electromagnet, and the brake friction pad is mounted on the electromagnet; the electromagnetic coil controls the elastic deformation of the elastic clamp, so that the elastic cantilevers on left and right sides of the elastic clamp attract or repel each other, so that the wheel hub brake disc brakes or releases the brake.

[0004] In order to achieve energy conservation and emission reduction, increase braking force, and reduce braking distance and time, a further technical solution includes a first braking mode. In the first braking mode, the elastic clamp is in a normally loose state, and the current directions of the electromagnetic coils on the left and right sides of the elastic clamp are the same. When the left and right electromagnetic coils are energized, the left and right electromagnets generate mutually attractive electromagnetic forces, causing the elastic cantilevers on the left and right sides of the elastic clamp to attract each other, and the elastic clamp clamps the wheel hub brake disc to achieve braking.

[0005] In order to improve vehicle safety, eliminate the parking brake, increase the braking force, and reduce the braking distance and time, a further technical solution includes a second braking mode. In the second braking mode, the elastic clamp is in a normally clamped state, and the current directions of the electromagnetic coils on the left and right sides of the elastic clamp are opposite. When the left and right electromagnetic coils are energized, the left and right electromagnets generate mutually repelling electromagnetic forces, causing the elastic cantilevers on the left and right sides of the elastic clamp to repel each other, and the elastic clamp releases the wheel hub brake disc to release the brake.

[0006] In order to extend the service life of the brake, a further technical solution includes a first braking mode and a second braking mode. In the second braking mode, the elastic clamp is in a normally clamped state, and the current directions of the electromagnetic coils on the left and right sides of the elastic clamp are opposite. When the left and right electromagnetic coils are energized, the two electromagnets on the left and right sides generate mutually repelling electromagnetic forces, so that the elastic cantilevers on the left and right sides of the elastic clamp repel each other, and the elastic clamp releases the wheel hub brake disc to release the brake.

[0007] In the first braking mode, the elastic clamp is in a normally loose state, and the current directions of the electromagnetic coils on the left and right sides of the elastic clamp are the same. When the left and right electromagnetic coils are energized, the two electromagnets generate electromagnetic forces that attract each other, so that the elastic cantilevers on the left and right sides of the elastic clamp attract each other, and the elastic clamp clamps the wheel hub brake disc to achieve braking;

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

[0009] In order to accurately control the power, braking distance and time, a further technical solution includes a controller, an electromagnetic driver, a speed sensor, and a current sensor; 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, and at the same time receives the output current feedback signal of the electromagnetic driver, and calculates and generates a control voltage according to the braking target speed. After receiving the control voltage, the electromagnetic driver outputs current to the electromagnetic coil.

[0010] In order to accurately control the power, 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 the control voltage u according to the braking time. c The relationship is:

[0011]

[0012] Among them, 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 drive is expressed as:

[0014]

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

[0016] The electromagnetic attraction or repulsion F of the electromagnet on the wheel brake disc e The expression of (i,x) is:

[0017]

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

[0019] Elastic force of elastic clamp F k The expression is:

[0020]

[0021] Where E is the elastic modulus of the elastic clip, l is the equivalent cantilever length of the elastic clip, I is the bending section coefficient of the elastic clip, δ k It is the displacement caused by the deformation of the elastic clamp under force.

[0022] Braking force F f The expression is:

[0023] F f =μF N

[0024] Where μ is the friction coefficient, F N It is the pressure of the brake friction pad on the wheel brake disc;

[0025] The pressure F of the brake friction pad on the wheel brake disc N The expression is:

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

[0027] The friction resistance torque T of the brake pad to the wheel brake disc f The expression is:

[0028] T f =F f R f

[0029] Among them, R fIt is the distance between the equivalent action point of the brake friction pad on the wheel hub brake disc and the center of the wheel hub brake disc (equivalent radius of the brake force action point).

[0030] Compared with the prior art, the electromagnetic wire-controlled brake control system for electric agricultural machinery of the present invention has the following beneficial effects:

[0031] 1. The electromagnetic coil controls the elastic deformation of the elastic clamp, so that the elastic cantilevers on the left and right sides of the elastic clamp attract or repel each other, so that the wheel hub brake disc brakes or releases the brake. It increases the braking force, reduces the braking distance and time, has a fast response time, good safety, reliability and sensitivity, a clever structure, and can accurately control the power, braking distance and time.

[0032] 2. The present invention includes two braking modes. When the first braking mode is adopted, during normal driving, the left and right electromagnetic coils shall not be powered, which reduces the power consumption, realizes energy conservation and emission reduction, increases the braking force, and reduces the braking distance and time. When the second braking mode is adopted, when the vehicle loses power, the left and right electromagnetic coils shall not be powered, and the vehicle is in a braking state, which improves the safety of the vehicle, eliminates the parking brake, increases the braking force, and reduces the braking distance and time. A mixed mode of the first braking mode and the second braking mode can also be adopted. When the vehicle is used in the second braking mode for a period of time, the brake friction pad is worn, and the elastic clamp cannot be in a normal clamping state, it can still be used normally when switched to the first braking mode, thereby extending the braking service life of the vehicle.

[0033] 3. The controller of the present invention compares the wheel speed signal with the target speed, receives the output current feedback signal of the electromagnetic driver, and calculates and generates the control voltage according to the braking target speed. After receiving the control voltage, the electromagnetic driver outputs current to the electromagnetic coil to achieve precise control of power, speed, braking distance and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0035] Figure 1 It is a three-dimensional schematic diagram of the electromagnetic wire-controlled brake device for electric agricultural machinery of the present invention;

[0036] Figure 2 for Figure 1 The main view;

[0037] Figure 3 This is a schematic diagram of the framework of the electromagnetic wire-controlled brake control system for electric agricultural machinery of the present invention;

[0038] Figure 4 It is a schematic diagram of the relationship curve between current and braking torque of the present invention;

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

[0040] Figure 6 Schematic diagram of braking distance of the present invention. DETAILED DESCRIPTION

[0041] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0042] like Figure 1 and Figure 2 As shown, the present invention preferably adopts an electromagnetic wire-controlled brake control system for electric agricultural machinery, including a wheel hub brake disc 1, an elastic clamp 2, an electromagnetic coil 3, an electromagnet 4, and a brake friction pad 5; the elastic clamp 2 is used to clamp the wheel hub brake disc 1, and the elastic clamp 2 is a U-shaped structure. The elastic clamp includes elastic cantilevers 20 on the left and right sides for clamping the wheel hub brake disc 1, and the elastic cantilevers 20 on the left and right sides are interconnected to form a U-shaped structure as a whole, the electromagnet 4 is installed on the elastic cantilevers 20 on the left and right sides of the elastic clamp 2, the electromagnetic coil 3 is installed on the electromagnet 4, and the brake friction pad 5 is installed on the electromagnet 4; the electromagnetic coil 3 controls the elastic deformation of the elastic clamp 2, so that the elastic cantilevers 20 on the left and right sides of the elastic clamp 2 attract or repel each other, so that the wheel hub brake disc 1 is braked or released.

[0043] The first braking mode is included. In the first braking mode, the elastic clamp 2 is in a normally released state. The current directions of the electromagnetic coils 3 on the left and right sides of the elastic clamp 2 are the same. When the left and right electromagnetic coils 3 are energized, the two electromagnets 4 on the left and right sides generate electromagnetic forces that attract each other, so that the elastic cantilevers 20 on the left and right sides of the elastic clamp 2 attract each other, and the elastic clamp 2 clamps the wheel hub brake disc 1 to achieve braking. When the left and right electromagnetic coils 3 are not energized, the elastic clamp 2 is in a normally released state, that is, the brake is released.

[0044] The second braking mode is included. In the second braking mode, the elastic clamp 2 is in a normally clamped state. The current directions of the electromagnetic coils 3 on the left and right sides of the elastic clamp 2 are opposite. When the left and right electromagnetic coils 3 are energized, the two electromagnets 3 on the left and right sides generate mutually repelling electromagnetic forces, so that the elastic cantilevers 20 on the left and right sides of the elastic clamp 2 repel each other, and the elastic clamp 2 releases the wheel hub brake disc 1 to release the brake. When the left and right electromagnetic coils 3 are not energized, the elastic clamp 2 is in a normally clamped state, that is, a braking state. Compared with the first braking mode, the second braking mode has better safety and reliability and faster response time.

[0045] When the vehicle is used in the second braking mode for a period of time, the brake friction pad 5 is worn and the elastic clamp 2 cannot be in a normal clamping state, it is switched to the first braking mode. The hybrid mode is adopted, and the switching is simple. It only needs to change the current direction of the electromagnetic coils 3 on the left and right sides to achieve the switching between the first braking mode and the second braking mode. Since the brake device is a wearing part, it can be switched to the first braking mode when the second braking mode fails, which can extend the service life of the brake.

[0046] like Figure 3 As shown, it includes a controller, an electromagnetic driver, a speed sensor, and a current sensor; 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, and 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 time, and after receiving the control voltage, the electromagnetic driver outputs current to the electromagnetic coil 3. Accurate control of power, braking distance and time is achieved.

[0047] 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 the control voltage u according to the braking time. c The relationship is:

[0048]

[0049] Among them, 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;

[0050] The output current i(t) of the electromagnetic drive is expressed as:

[0051]

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

[0053] The electromagnetic attraction or repulsion F of the electromagnet 4 on the wheel brake disc 1 e The expression of (i,x) is:

[0054]

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

[0056] C e The expression is

[0057]

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

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

[0060]

[0061] Where, E is the elastic modulus of the elastic clamp 2, l is the equivalent cantilever length of the elastic clamp 2, I is the bending section coefficient of the elastic clamp 2, δ k It is the displacement caused by the deformation of the elastic clamp under force.

[0062] The expression of bending section coefficient I is:

[0063]

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

[0065] The braking force expression is:

[0066] F f =μF N

[0067] Among them, F f is the friction force of the brake friction pad 5 on the wheel hub brake disc 1, μ is the friction coefficient, F N It is the pressure of the brake friction pad 5 on the wheel hub brake disc 1.

[0068] The pressure F of the brake friction pad 5 on the wheel brake disc 1 N The expression is:

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

[0070] The friction resistance torque T of the brake friction pad 5 to the wheel hub brake disc 1 f The expression is:

[0071] T f =F f R f

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

[0073] like Figure 4 As shown in the figure, in the first braking mode, the relationship curve between the current and the braking torque of the electromagnetic wire-controlled brake of the electric agricultural machinery is mainly divided into two stages. The full-stage current range 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 latter stage, the current is greater than 3.57A, at which time the electromagnetic suction force 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 the current.

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

[0075] like Figure 6 As shown in the figure, in the first braking mode, the braking distance curve of the electromagnetic wire-controlled brake of the electric agricultural machinery, the mass of the agricultural machinery 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An electromagnetic wire-controlled brake control system for electric agricultural machinery, characterized in that: The invention comprises a wheel hub brake disc (1), an elastic clamp (2), an electromagnetic coil (3), an electromagnet (4), and a brake friction pad (5); the elastic clamp (2) comprises elastic cantilevers (20) on the left and right sides for clamping the wheel hub brake disc (1); the elastic cantilevers (20) on the left and right sides are connected to each other; the electromagnet (4) is mounted on the elastic cantilevers (20) on the left and right sides of the elastic clamp (2); the electromagnetic coil (3) is mounted on the electromagnet (4); and the brake friction pad (5) is mounted on the electromagnet (4); the electromagnetic coil (3) controls the elastic deformation of the elastic clamp (2) so that the elastic cantilevers (20) on the left and right sides of the elastic clamp (2) attract or repel each other, so that the wheel hub brake disc (1) is braked or released.

2. An electromagnetic wire-controlled brake control system for electric agricultural machinery according to claim 1, characterized in that: The invention comprises a first braking mode. In the first braking mode, the elastic clamp (2) is in a normally loosened state, the current directions of the electromagnetic coils (3) located on the left and right sides of the elastic clamp (2) are the same, and when the left and right electromagnetic coils (3) are energized, the two electromagnets (4) on the left and right sides generate electromagnetic forces that attract each other, so that the elastic cantilevers (20) on the left and right sides of the elastic clamp (2) attract each other, and the elastic clamp (2) clamps the wheel hub brake disc (1) to achieve braking.

3. An electromagnetic wire-controlled brake control system for electric agricultural machinery according to claim 1, characterized in that: The invention comprises a second braking mode. In the second braking mode, the elastic clamp (2) is in a normally clamped state, and the current directions of the electromagnetic coils (3) located on the left and right sides of the elastic clamp (2) are opposite. When the left and right electromagnetic coils (3) are energized, the two electromagnets (3) on the left and right sides generate mutually repelling electromagnetic forces, so that the elastic cantilevers (20) on the left and right sides of the elastic clamp (2) repel each other, and the elastic clamp (2) releases the wheel hub brake disc (1) to release the brake.

4. An electromagnetic wire-controlled brake control system for electric agricultural machinery according to claim 1, characterized in that: The invention comprises a first braking mode and a second braking mode. In the second braking mode, the elastic clamp (2) is in a normally clamped state, and the current directions of the electromagnetic coils (3) located on the left and right sides of the elastic clamp (2) are opposite. When the left and right electromagnetic coils (3) are energized, the two electromagnets (3) on the left and right sides generate mutually repelling electromagnetic forces, so that the elastic cantilevers (20) on the left and right sides of the elastic clamp (2) repel each other, and the elastic clamp (2) releases the wheel hub brake disc (1) to release the brake. In the first braking mode, the elastic clamp (2) is in a normally loosened state, and the current directions of the electromagnetic coils (3) located on the left and right sides of the elastic clamp (2) are the same. When the left and right electromagnetic coils (3) are energized, the two left and right electromagnets (4) generate electromagnetic forces that attract each other, so that the elastic cantilevers (20) on the left and right sides of the elastic clamp (2) attract each other, and the elastic clamp (2) clamps the wheel hub brake disc (1) to achieve braking; When the vehicle is used in the second braking mode for a period of time, the brake friction pad (5) is worn and the elastic clamp (2) cannot be in a normal clamping state, the vehicle is switched to the first braking mode.

5. An electromagnetic wire-controlled brake control system for electric agricultural machinery according to any one of claims 1 to 4, characterized in that: The invention comprises a controller, an electromagnetic driver, a speed sensor and a current sensor; 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; after receiving the control voltage, the electromagnetic driver outputs current to the electromagnetic coil (3).

6. The electromagnetic wire-controlled brake control system for electric agricultural machinery according to claim 5, characterized in that: 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 the control voltage u according to the braking time. c The relationship is: Among them, 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; The output current i(t) of the electromagnetic drive is expressed as: Among them, K a is the amplification parameter of the electromagnetic drive, u c is the control voltage, and R is the resistance of the electromagnetic coil (3). The electromagnetic attraction or repulsion F of the electromagnet (4) on the wheel brake disc (1) e The expression of (i,x) is: Where i(t) is the current passing through the copper coil, x(t) is the distance between the electromagnet pole and the wheel brake disc, C e is the electromagnetic force coefficient; Elastic clamp (2) elastic force F k The expression is: Wherein, E is the elastic modulus of the elastic clamp (2), l is the equivalent cantilever length of the elastic clamp (2), I is the bending section coefficient of the elastic clamp (2), δ k It is the displacement caused by the deformation of the elastic clamp under force. The braking force expression is: F f =μF N Among them, F f is the friction force of the brake friction pad (5) on the wheel hub brake disc (1), μ is the friction coefficient, F N is the pressure of the brake friction pad (5) on the wheel hub brake disc (1); The pressure F of the brake friction pad (5) on the wheel hub brake disc (1) N The expression is: F N =F e (i,x)-F k The friction resistance torque T of the brake friction pad (5) to the wheel hub brake disc (1) f The expression is: T f =F f R f Among them, R f It is the distance between the equivalent action point of the brake friction pad on the wheel hub brake disc (1) and the center of the wheel hub brake disc (1).

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