Proportional braking electric cylinder and control method

Abstract

The invention provides a proportional braking electric cylinder and a control method. The electric cylinder comprises a cylinder body which comprises a cylinder barrel and a rod barrel, and a lead screw is arranged in the cylinder barrel to drive the rod barrel to drive a load to stretch out and draw back; the driving motor serves as a driving source of the electric cylinder and is in transmission connection with the lead screw through a speed reducer; the power-on brake is arranged between the driving motor and the speed reducer; and the controller is configured to control the power-on brake when the electric cylinder is started and braked. Proportional braking is achieved through the power-on brake, and in the dynamic starting and braking process of the electric cylinder, the power-on brake can provide dynamic braking force so as to prevent the electric cylinder from sinking during starting and impacting during braking stopping.

Description

Technical Field

[0001] The invention relates to a proportional brake electric cylinder and a control method thereof. Background Art

[0002] Existing electric cylinder brakes use either a single brake or dual brake solution. The single brake solution can only achieve either locking the electric cylinder or preventing stalling. The dual brake solution uses a centrifugal brake and an electromagnetic brake at the motor end. The centrifugal brake uses the centrifugal force of the brake pad to drive the friction lining into contact with the brake drum. The faster the speed, the greater the braking torque, thereby limiting the speed of the electric cylinder to a safe range and preventing stalling. The electromagnetic brake is usually integrated with the motor, braking in the de-energized state and releasing the brake when powered on, allowing the electric cylinder to lock at any position. However, existing electric cylinder de-energized braking is switch-controlled, providing a static locking function and not dynamic braking, thus failing to achieve a proportional braking effect. The instantaneous impact of de-energized braking after the motor brakes, and the risk of sinking when the de-energized brake is released during motor startup, can be significant. Summary of the Invention

[0003] The purpose of the present invention is to provide a proportional braking electric cylinder, which realizes proportional braking through an electrified brake. During the dynamic process of starting and braking the electric cylinder, the electrified brake can provide dynamic braking force to prevent the electric cylinder from sinking when starting and generating impact when stopping.

[0004] In a first aspect, the present invention provides a proportional brake electric cylinder comprising: The cylinder body comprises a cylinder barrel and a rod barrel, wherein a lead screw is provided in the cylinder barrel to drive the rod barrel to extend and retract the load; The driving motor, as the driving source of the electric cylinder, is connected to the lead screw through the reducer; An electric brake is provided between the drive motor and the reducer; A controller is configured to control the energized brake when the electric cylinder is activated and braked.

[0005] Optionally, it also includes: The lead screw nut is used to fix the lead screw in the cylinder.

[0006] Optionally, it also includes: An encoder is configured to measure the rotation speed and number of revolutions of the input shaft of the gearbox to determine the telescopic speed and telescopic displacement of the rod barrel.

[0007] Optionally, the electrified brake can provide braking force when energized.

[0008] Optionally, the braking force of the electrified brake is dynamically adjusted through voltage PWM control.

[0009] Optionally, the braking force of the electric brake is controlled by an electric handle.

[0010] Optionally, the cylinder is mounted on a base.

[0011] In a second aspect, the present invention provides a control method for a proportional brake electric cylinder, which is implemented based on the proportional brake electric cylinder. The control method includes: When the electric cylinder is started, the energized brake is controlled using a first strategy; When the electric cylinder is braking, a second strategy is used to control the energized brake.

[0012] Optionally, the controlling the energized brake using a first strategy includes: In response to a start instruction of the electric cylinder, determining a target braking force of the energized brake according to a current load force of the electric cylinder; energizing the powered brake and increasing the braking force to the target braking force according to a preset strategy to keep the load stationary; Starting the drive motor, and in response to the driving force of the drive motor exceeding the braking force of the energized brake, reducing the braking force of the energized brake according to a preset rule; In response to the driving force of the driving motor exceeding the load force, the energized brake is de-energized and the brake is released, and the driving motor drives the load to work.

[0013] Optionally, the controlling the energized brake using the second strategy includes: In response to a braking instruction from the electric cylinder, the drive motor is decelerated and a target braking force of the energized brake is determined according to a current load force of the electric cylinder; In response to the rotation speed of the drive motor being less than a set value, energizing the electric brake and increasing the braking force to the target braking force according to a preset strategy; In response to the driving motor's rotational speed dropping to zero and stopping outputting driving force, the energized brake remains energized and the load is kept stationary by the braking force of the energized brake.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention realizes proportional braking through an electric brake. During the dynamic process of starting and braking the electric cylinder, the electric brake can provide dynamic braking force to prevent the electric cylinder from sinking when starting and generating impact when stopping.

[0015] 2. When the electric cylinder is started, the present invention first provides a braking force that can match the load force through the energized brake. When the driving force of the driving motor exceeds the braking force, the braking force is reduced. When the driving force of the driving motor is greater than the load force, the load can be directly driven by the driving motor to work. The present invention eliminates the risk of load sinking caused by the instantaneous release of the traditional de-energized brake by allowing the driving force to gradually overcome the braking force and the load force.

[0016] 3. During the braking process, the present invention gradually increases the braking force through the energized brake to achieve dynamic deceleration of the drive motor. After the drive motor decelerates to zero and stops outputting torque, the braking force provided by the energized brake first keeps the load stationary, and then the de-energized brake takes over the locking. The energized brake is de-energized to release the brake, thereby avoiding the impact vibration caused by the instantaneous locking of the mechanical brake in the traditional solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the proportional brake electric cylinder in Example 1; Figure 2 This is a flow chart of the control method in Example 2.

[0018] Numbers in the figure: 1, driving motor; 2, power-off brake; 3, power-on brake; 4, reducer; 5, gearbox; 6, encoder; 7, pressure sensor; 8, base, 9; screw nut; 10, screw; 11, cylinder; 12, rod barrel. DETAILED DESCRIPTION

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0020] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Example 1

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0022] Combine Figure 1This embodiment provides a proportional brake electric cylinder, comprising a cylinder body, a drive motor 1, an electric brake 3, and a controller. The cylinder body comprises a cylinder barrel 11 and a rod barrel 12. The cylinder body is mounted on a base 8. A lead screw 10 is disposed within the cylinder barrel 11 to drive the rod barrel 12 to extend and retract the load. The lead screw 10 is secured within the cylinder barrel 11 by a lead screw nut 9. The drive motor 1, serving as the drive source for the electric cylinder, is sequentially connected to the lead screw 10 via a reducer 4 and a gearbox 5. The electric brake 3 is disposed between the drive motor 1 and the reducer 4. The electric brake 3 provides braking force when energized and releases the brake when de-energized. The electric brake 3 can achieve proportional braking with varying braking torques through voltage PWM control. The controller is configured to control the electric brake 3 during startup and braking of the electric cylinder. This embodiment utilizes the electric brake 3 to provide varying braking forces to achieve proportional braking, preventing the electric cylinder from sinking during startup and impacting during shutdown.

[0023] The electric cylinder also includes an encoder 6, a pressure sensor 7, and a power-off brake 2. The encoder 6 measures the input shaft speed and revolutions of the gearbox 5. By converting the speed ratio, the extension and retraction speed and displacement of the electric cylinder's rod barrel 12 can be calculated. The pressure sensor 7, located directly below the cylinder barrel 11, measures the pressure in the electric cylinder to determine the load force. The power-off brake 2 allows the electric cylinder to be locked at any position.

[0024] The deenergized brake 2 is connected between the drive motor 1 and the energized brake 3. This embodiment utilizes a dual-brake structure comprising the energized brake 3 and the deenergized brake 2. The locking braking force provided by the deenergized brake 2 during a power outage enables the electric cylinder to be locked when power is lost. The dynamic braking force provided by the energized brake 3 enables proportional braking of the electric cylinder, preventing it from sinking during startup and impacting during shutdown. In this embodiment, the energized brake 3 and the deenergized brake 2 can be integrated or independently arranged at the motor end or elsewhere in the transmission chain. Example 2

[0025] Combine Figure 2 This embodiment provides a control method for the proportional brake electric cylinder described in embodiment 1, which includes: When the electric cylinder is started, the energized brake 3 is controlled using a first strategy; When the electric cylinder is braking, the second strategy is used to control the energized brake 3 .

[0026] The control method in this embodiment mainly provides dynamic braking force by the energized brake 3 during the dynamic process of starting and braking the electric cylinder, so as to prevent the electric cylinder from sinking during starting and impacting during braking.

[0027] Specifically, using the first strategy to control the energized brake 3 includes: responding to a start command from the electric cylinder, determining a target braking force for the energized brake 3 based on the current load force of the electric cylinder (collected by the pressure sensor 7 at the bottom of the cylinder barrel 11); energizing the energized brake 3 and increasing the braking force (according to a preset rule, which may be linear or nonlinear, determined according to actual needs) to the target braking force to maintain the load stationary through the braking force of the energized brake; starting the drive motor 1, and in response to the driving force of the drive motor 1 exceeding the braking force of the energized brake 3, reducing the braking force of the energized brake 3 according to a preset rule (which may be linear or nonlinear, determined according to actual needs); and in response to the driving force of the drive motor 1 exceeding the load force, de-energizing the energized brake 3 and releasing the brake, and then the drive motor 1 drives the load to operate. Through the above strategy, this embodiment can smoothly activate the electric cylinder through the dynamic braking force of the energized brake 3 to prevent the load from sinking.

[0028] In another specific embodiment, a de-energized brake 2 is further connected between the drive motor 1 and the energized brake 3; the de-energized brake 2 remains de-energized when the electric cylinder is not operating to provide a locking braking force. Before the electric cylinder is activated, the de-energized brake 2 is de-energized and provides a locking braking force to lock the drive motor. When the braking force of the energized brake 3 reaches the target braking force, the de-energized brake 2 is energized to release the brake, and the braking force of the energized brake 3 is used to hold the load stationary. The de-energized brake 2 can provide a locking braking force to hold the load stationary before the electric cylinder is deactivated and the braking force of the energized brake 3 increases to the target braking force, thereby achieving stable startup of the electric cylinder and preventing the load from sinking.

[0029] Furthermore, the use of the second strategy to control the electrified brake 3 includes: responding to the braking instruction of the electric cylinder, causing the drive motor 1 to decelerate through its own braking (the specific deceleration is determined according to actual conditions) and determining the target braking force of the electrified brake 3 according to the current load force of the electric cylinder. At this time, the electrified brake 3 does not intervene in the deceleration of the drive motor 1 to avoid direct intervention and impact when the drive motor 1 is running at high speed. In response to the speed of the drive motor 1 being less than the set value (the electrified brake can safely intervene), the electrified brake 3 is energized and the braking force is increased (linearly increased or nonlinearly increased, determined according to actual needs) to the target braking force. During the process of increasing the braking force, dynamic braking of the electric cylinder can be achieved to avoid impact; in response to the speed of the drive motor 1 dropping to zero and stopping outputting the driving force, the electrified brake 3 remains energized and the load is kept stationary by the braking force of the electrified brake 3. The above method can ensure that the load remains stable while achieving smooth braking of the drive motor.

[0030] In another specific embodiment, a de-energized brake 2 is further connected between the drive motor 1 and the energized brake 3; before the electric cylinder starts braking, the de-energized brake 2 remains energized; when the speed of the drive motor 1 drops to zero and stops outputting driving force, the de-energized brake 2 is de-energized to provide locking braking force to keep the load stationary, and the energized brake 3 is de-energized to release the brake.

[0031] In addition, when the electric cylinder is about to stall, the energized brake 3 and the de-energized brake 2 can intervene in time to provide auxiliary braking force to limit the rotation speed of the electric cylinder to a safe range, thereby preventing the electric cylinder from stalling.

[0032] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A proportional brake electric cylinder, characterized in that: include: The cylinder body comprises a cylinder barrel and a rod barrel, wherein a lead screw is provided in the cylinder barrel to drive the rod barrel to extend and retract the load; The driving motor, as the driving source of the electric cylinder, is connected to the lead screw through the reducer; An electric brake is provided between the drive motor and the reducer; A controller is configured to control the energized brake when the electric cylinder is activated and braked.

2. The proportional brake electric cylinder according to claim 1, characterized in that: Also includes: The lead screw nut is used to fix the lead screw in the cylinder.

3. The proportional brake electric cylinder according to claim 1, characterized in that: Also includes: An encoder is configured to measure the rotation speed and number of revolutions of the input shaft of the gearbox to determine the telescopic speed and telescopic displacement of the rod barrel.

4. The proportional brake electric cylinder according to claim 1, characterized in that: The electrified brake can provide braking force when energized.

5. The proportional brake electric cylinder according to claim 4, characterized in that: The braking force of the electrified brake is dynamically adjusted through voltage PWM control.

6. The proportional brake electric cylinder according to claim 4, characterized in that: The braking force of the electric brake is controlled by an electric handle.

7. The proportional brake electric cylinder according to claim 1, characterized in that: The cylinder body is mounted on a base.

8. A control method for a proportional brake electric cylinder, characterized in that: Based on the proportional brake electric cylinder according to any one of claims 1 to 7, the control method includes: When the electric cylinder is started, the energized brake is controlled using a first strategy; When the electric cylinder is braking, a second strategy is used to control the energized brake.

9. The control method of a proportional brake electric cylinder according to claim 8, characterized in that: The controlling the energized brake using the first strategy includes: In response to a start instruction of the electric cylinder, determining a target braking force of the energized brake according to a current load force of the electric cylinder; energizing the powered brake and increasing the braking force to the target braking force according to a preset strategy to keep the load stationary; Starting the drive motor, and in response to the driving force of the drive motor exceeding the braking force of the energized brake, reducing the braking force of the energized brake according to a preset rule; In response to the driving force of the driving motor exceeding the load force, the energized brake is de-energized and the brake is released, and the driving motor drives the load to work.

10. The control method of a proportional brake electric cylinder according to claim 8, characterized in that: The using the second strategy to control the energized brake comprises: In response to a braking command from the electric cylinder, the drive motor is decelerated and a target braking force of the energized brake is determined according to a current load force of the electric cylinder; In response to the rotation speed of the drive motor being less than a set value, energizing the electric brake and increasing the braking force to the target braking force according to a preset strategy; When the rotation speed of the drive motor drops to zero and stops outputting the driving force, the electric brake remains energized and provides the braking force required to keep the load stationary.

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