Load sensing brake electric cylinder and control method and control system thereof

Abstract

The invention provides a load sensing brake electric cylinder and a control method and system thereof. The load sensing brake electric cylinder comprises a cylinder barrel, a gearbox, an encoder, a pressure sensor and at least two sets of driving motors and speed reducers. A plurality of brakes are connected in series between each group of driving motors and speed reducers, and the driving motors, the speed reducers and the brakes are dynamically coupled through gear boxes; the encoder is used for measuring the rotating speed of the input shaft of the gearbox; the pressure sensor is used for measuring the pressure of the cylinder barrel; and when the electric cylinder needs to be braked, the brakes with the corresponding number are selected for braking according to different pressure signals and rotating speed signals. The load sensing electric cylinder can conduct braking according to different operation conditions, the working safety is guaranteed, meanwhile, braking impact caused by excess braking force is avoided, the system response time is shortened, and the control performance is improved.

Description

Technical Field

[0001] The invention relates to a load-sensing brake electric cylinder and a control method and a control system thereof, belonging to the field of electric cylinder brakes. Background Art

[0002] Existing electric cylinder brakes use two types of solutions: single brake and dual brake solutions. The single brake solution can only achieve one of the functions of locking the electric cylinder or preventing stalling. The dual brake solution arranges a centrifugal brake and an electromagnetic brake at the motor end. The centrifugal brake drives the friction lining to contact the brake drum through the centrifugal action of the brake block. The faster the speed, the greater the braking torque, thereby limiting the speed of the electric cylinder to a safe range and preventing the electric cylinder from stalling. The electromagnetic brake is usually integrated with the motor, braking in the power-off state and releasing the brake when powered on, allowing the electric cylinder to lock at any position. However, existing electric cylinder braking solutions all use the speed signal of the electric cylinder for static braking, without controlling according to the load conditions. The braking impact is large at high speed and heavy load, and the response is slow at low speed and light load.

[0003] The existing technologies all use single-motor electric cylinders, which brake based on the speed signal of the electric cylinder without controlling the load. The braking impact is large at high speed and heavy load, and the response is slow at low speed and light load. Summary of the Invention

[0004] The present invention provides a load-sensing brake electric cylinder and a control method and control system thereof, which solve the problems disclosed in the background technology.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A load-sensing brake electric cylinder comprises a cylinder, a gearbox, an encoder, a pressure sensor, and at least two sets of drive motors and reducers; a plurality of brakes are connected in series between each set of drive motors and reducers, and the drive motors, reducers, and the plurality of brakes are power-coupled via the gearbox; the encoder is used to measure the speed of the gearbox input shaft; the pressure sensor is used to measure the cylinder pressure; when the electric cylinder needs to brake, a corresponding number of brakes are selected for braking according to different pressure signals and speed signals.

[0007] Furthermore, the number of the brakes is four.

[0008] The present invention also provides a control method for a load-sensing brake electric cylinder: a pressure sensor collects a pressure signal F, an encoder collects a speed signal ω and compares them with a set heavy load threshold F. m , light load threshold F n , low speed threshold ω n Make comparisons;

[0009] When F≤F n, or ω≤ω n And F n <F≤F m When the electric cylinder is judged to be in light load condition or low speed medium load condition, two brakes are selected for braking;

[0010] When ω>ω n And F n <F≤F m , or F>F m When the electric cylinder is judged to be in a medium-high speed medium load condition or a heavy load condition, four brakes are selected for braking at the same time.

[0011] Furthermore,

[0012] When ω≤ω n and F≤F n When the electric cylinder is judged to be in low speed and light load working condition, a brake is selected for braking;

[0013] When ω>ω n and F≤F n When the electric cylinder is judged to be in the medium-high speed and light-load working condition, two brakes are selected for braking;

[0014] When ω≤ω n And F n <F≤F m When , it is determined that the electric cylinder is in low speed and medium load working condition, and two brakes are selected for braking;

[0015] When ω>ω n And F n <F≤F m When the electric cylinder is judged to be in the medium-high speed and medium-load working condition, three brakes are selected for braking;

[0016] When F>F m When the electric cylinder is judged to be in heavy-load condition, four brakes are selected for braking.

[0017] The present invention also provides a second control method for a load-sensing brake electric cylinder: a pressure sensor collects a pressure signal F and a set heavy load threshold F m and light load threshold F n Make comparisons;

[0018] When F≤F m When , it is determined that the electric cylinder is in light-medium load condition, and two brakes are selected for braking;

[0019] When F>F m When the electric cylinder is judged to be in heavy-load condition, four brakes are selected for braking.

[0020] Furthermore,

[0021] When F≤F n When the electric cylinder is judged to be in light load condition, a brake is selected for braking;

[0022] When F n <F≤F m When , it is determined that the electric cylinder is in medium load condition and two brakes are selected for braking;

[0023] When F>F m When the electric cylinder is judged to be in heavy-load condition, four brakes are selected for braking.

[0024] The present invention also provides a third method for controlling a load-sensing brake electric cylinder: a pressure signal F is collected by a pressure sensor, a speed signal ω is collected by an encoder, and the required braking force Tbrake is calculated and compared with the braking force T0 of each brake;

[0025] When T 制动 When <2T0, two brakes are selected for braking;

[0026] When 2T0≤T 制动 When <4T0, the four brakes brake simultaneously.

[0027] Further,

[0028] When Tbrake < T0, select a brake for braking;

[0029] When T0≤T 制动 When <2T0, two brakes are selected for braking;

[0030] When 2T0≤T 制动 When <3T0, three brakes are selected for braking;

[0031] When 3T0≤T 制动 When <4T0, the four brakes brake simultaneously.

[0032] Further, ;

[0033] Where L is the lead of the screw, i1 is the speed ratio of the reducer, i2 is the speed ratio of the gearbox, η is the total transmission efficiency, t is the braking time, and g is the acceleration due to gravity.

[0034] The present invention also provides an electric cylinder control system, comprising a controller, a driver and a power supply, and is characterized in that it also comprises the load-sensing brake electric cylinder as described above.

[0035] The beneficial effects achieved by the present invention are:

[0036] The load-sensing electric cylinder of the present invention can brake according to different operating conditions, ensuring working safety while avoiding braking shock caused by excessive braking force, shortening system response time and improving control performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the structural principle of the electric cylinder of the present invention;

[0038] Figure 2 This is a flow chart of a load-sensing braking method according to the present invention;

[0039] Figure 3 This is a schematic diagram of the second flow chart of the load-sensing braking method of the present invention;

[0040] Figure 4 Schematic diagram of the third process of the load-sensing braking method of the present invention;

[0041] Figure 5 Schematic diagram of the electric cylinder control system of the present invention.

[0042] Reference numerals:

[0043] 1-controller, 2-driver, 3-electric cylinder, 4-power supply;

[0044] 3-1- drive motor, 3-2- brake a, 3-3- brake b, 3-4- reducer,

[0045] 3-5-gearbox, 3-6-encoder, 3-7-pressure sensor, 3-8-base,

[0046] 3-9-screw nut, 3-10-screw, 3-11-cylinder, 3-12-rod barrel, 3-13-rod head. DETAILED DESCRIPTION

[0047] 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.

[0048] Example 1:

[0049] like Figure 1As shown, this embodiment provides a load-sensing brake electric cylinder, comprising a gearbox 3-5, an encoder 3-6, a pressure sensor 3-7, a ball screw pair (screw nut 3-9, screw 3-10), a cylinder body (cylinder barrel 3-11, rod barrel 3-12, rod head 3-13), two drive motors 3-1, brake a 3-2, brake b 3-3, and a reducer 3-4. The two drive motors 3-1, brake a 3-2, brake b 3-3, and reducer 3-4 are all power-coupled via the gearbox 3-5. One of the two drive motors serves as the main drive motor, and the other as the auxiliary drive motor. Under light loads, the main drive motor drives alone, while under medium or heavy loads, both drive motors drive simultaneously. Alternatively, the two drive motors can output torque in a 1:1 ratio. Brake a 3-2 and brake b 3-3 are arranged in series between the drive motor 3-1 and the reducer 3-4, enabling the electric cylinder to be locked at any position.

[0050] Encoder 3-6 measures the speed and rotational speed of the input shaft of gearbox 3-5. By converting the speed ratio, the extension and retraction speed and displacement of the electric cylinder can be calculated. Pressure sensor 3-7, located directly below cylinder barrel 3-11, measures the pressure in the electric cylinder. When the electric cylinder needs to brake, the corresponding number of brakes is selected based on the pressure and speed signals.

[0051] Example 2:

[0052] This embodiment provides a control method for a load-sensing brake electric cylinder based on the first embodiment, including the following three control methods:

[0053] like Figure 2 As shown in the figure, the control method of load-sensing brake electric cylinder is as follows: by collecting the pressure signal F of the pressure sensor and the speed signal ω of the encoder and respectively comparing them with the set heavy load threshold F m , light load threshold F n , and high speed threshold ω m , low speed threshold ω n Comparison is made to select different numbers of brakes for braking.

[0054] Preferred braking solution:

[0055] When the electric cylinder is in low speed and light load condition, that is, ω≤ω n and F≤F n , select a brake for braking.

[0056] When the electric cylinder is in the medium-high speed and light-load condition, that is, ω>ω n and F≤F n , select two brakes for braking.

[0057] When the electric cylinder is in low speed and medium load condition, that is, ω≤ω n And F n<F≤F m , select two brakes for braking.

[0058] When the electric cylinder is in the medium-high speed and medium-load condition, that is, ω>ω n And F n <F≤F m , select three brakes to brake simultaneously.

[0059] When the electric cylinder is in heavy load condition, that is, F>F m , four brakes brake simultaneously.

[0060] Optional braking options:

[0061] When the electric cylinder is in light load condition or low speed medium load condition, that is, F≤F n , or ω≤ω n And F n <F≤F m , select two brakes for braking.

[0062] When the electric cylinder is in medium-high speed medium load condition or heavy load condition, that is, ω>ω n And F n <F≤F m , or F>F m , four brakes brake simultaneously.

[0063] High speed threshold ω m It can be used as a warning value. When the speed approaches or exceeds ω m Send an early warning signal to the operator.

[0064] like Figure 3 As shown in the figure, the second control method of the load-sensing brake electric cylinder is to collect the pressure signal F of the pressure sensor and the set heavy load threshold F m , light load threshold F n Comparison is made to select different numbers of brakes for braking.

[0065] Preferred braking solution:

[0066] When the electric cylinder is in light load condition, that is, F≤F n , select a brake for braking.

[0067] When the electric cylinder is in medium load condition, that is, F n <F≤F m , select two brakes for braking.

[0068] When the electric cylinder is in heavy load condition, that is, F>F m , four brakes brake simultaneously.

[0069] Optional braking options:

[0070] When the electric cylinder is in light to medium load condition, that is, F≤F m , select two brakes for braking.

[0071] When the electric cylinder is in heavy load condition, that is, F>F m , four brakes brake simultaneously.

[0072] like Figure 4 As shown in the figure, the third control method of the load-sensing brake electric cylinder is to calculate the required braking force T by collecting the pressure signal F of the pressure sensor and the speed signal ω of the encoder. 制动 The braking force T0 of each brake is compared to select different numbers of brakes for braking.

[0073]

[0074] Among them, L is the lead of the screw, i1 is the speed ratio of the reducer, i2 is the speed ratio of the gearbox, η is the total transmission efficiency, t is the braking time, and g represents the acceleration due to gravity.

[0075] Preferred braking solution:

[0076] When T 制动 When <T0, select a brake for braking.

[0077] When T0≤T 制动 When <2T0, two brakes are selected for braking.

[0078] When 2T0≤T 制动 When <3T0, three brakes are selected for braking.

[0079] When 3T0≤T 制动 When <4T0, the four brakes brake simultaneously.

[0080] Optional braking options:

[0081] When T 制动 When <2T0, two brakes are selected for braking.

[0082] When 2T0≤T 制动 When <4T0, the four brakes brake simultaneously.

[0083] The load-sensing braking method of electric cylinders is also applicable to single-motor or multi-motor electric cylinders.

[0084] Example 3:

[0085] like Figure 5 As shown, this embodiment provides an electric cylinder control system, including a controller 1, a driver 2 and a power supply 4, and also includes the load-sensing brake electric cylinder 3 as in the above embodiment.

[0086] The power supply 4 outputs electrical energy to the driver 2, the driver 2 inputs a driving signal to the electric cylinder 3, the electric cylinder sends a pressure signal, a speed signal, and a displacement signal to the controller 1, the controller 1 adjusts the driving signal and sends it to the driver 2, and the driver 2 recycles excess energy to the power supply 4 for storage.

[0087] 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.

[0088] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A load-sensing brake electric cylinder, characterized in that: It includes a cylinder, a gearbox, an encoder, a pressure sensor and at least two sets of drive motors and reducers; several brakes are connected in series between each set of drive motors and reducers, and the drive motors, reducers and several brakes are dynamically coupled through the gearbox; the encoder is used to measure the speed of the gearbox input shaft; the pressure sensor is used to measure the cylinder pressure; when the electric cylinder needs to brake, the corresponding number of brakes are selected for braking according to different pressure signals and speed signals.

2. The load-sensing brake electric cylinder according to claim 1, characterized in that: The number of the brakes is four.

3. The control method of the load-sensing brake electric cylinder according to claim 2, characterized in that: The pressure signal F is collected by the pressure sensor, and the speed signal ω is collected by the encoder and compared with the set heavy load threshold F. m , light load threshold F n , low speed threshold ω n Make comparisons; When F≤F n , or ω≤ω n And F n <F≤F m When the electric cylinder is judged to be in light load condition or low speed medium load condition, two brakes are selected for braking; When ω>ω n And F n <F≤F m , or F>F m When the electric cylinder is judged to be in a medium-high speed medium load condition or a heavy load condition, four brakes are selected for braking at the same time.

4. The control method of the load-sensing brake electric cylinder according to claim 3, characterized in that: When ω≤ω n and F≤F n When the electric cylinder is judged to be in low speed and light load working condition, a brake is selected for braking; When ω>ω n and F≤F n When the electric cylinder is judged to be in the medium-high speed and light-load working condition, two brakes are selected for braking; When ω≤ω n And F n <F≤F m When , it is determined that the electric cylinder is in low speed and medium load working condition, and two brakes are selected for braking; When ω>ω n And F n <F≤F m When the electric cylinder is judged to be in the medium-high speed and medium-load working condition, three brakes are selected for braking; When F>F m When the electric cylinder is judged to be in heavy-load condition, four brakes are selected for braking.

5. The control method of the load-sensing brake electric cylinder according to claim 2, characterized in that: The pressure sensor collects the pressure signal F and the set overload threshold F m and light load threshold F n Make comparisons; When F≤F m When , it is determined that the electric cylinder is in light-medium load condition, and two brakes are selected for braking; When F>F m When the electric cylinder is judged to be in heavy-load condition, four brakes are selected for braking.

6. The control method of the load-sensing brake electric cylinder according to claim 5, characterized in that: When F≤F n When the electric cylinder is judged to be in light load condition, a brake is selected for braking; When F n <F≤F m When , it is determined that the electric cylinder is in medium load condition and two brakes are selected for braking; When F>F m When the electric cylinder is judged to be in heavy-load condition, four brakes are selected for braking.

7. The control method of the load-sensing brake electric cylinder according to claim 2, characterized in that: The pressure signal F is collected by the pressure sensor, and the speed signal ω is collected by the encoder. The required braking force Tbrake is calculated and compared with the braking force T0 of each brake; When T 制动 When <2T0, two brakes are selected for braking; When 2T0≤T 制动 When <4T0, the four brakes brake simultaneously.

8. The control method of the load-sensing brake electric cylinder according to claim 7, characterized in that: When T 制动 When <T0, select a brake for braking; When T0≤T 制动 When <2T0, two brakes are selected for braking; When 2T0≤T 制动 When <3T0, three brakes are selected for braking; When 3T0≤T 制动 When <4T0, the four brakes brake simultaneously.

9. The control method of the load-sensing brake electric cylinder according to claim 7, characterized in that: ; Wherein, L represents the lead of the screw, i1 represents the speed ratio of the reducer, i2 represents the speed ratio of the gearbox, η represents the total transmission efficiency, t represents the braking time, and g represents the acceleration due to gravity.

10. An electric cylinder control system, comprising a controller, a driver and a power supply, characterized in that: It also includes the load-sensing brake electric cylinder as claimed in claim 1 or 2.

Images