System for realizing intelligent control identification by using limit switch in electric push rod

Abstract

The invention provides a system for realizing intelligent control identification by using an internal limit switch of an electric push rod, which comprises a CPU control module, a push rod body, a state feedback module and a power driving module, the state feedback module comprises a leakage current acquisition sensor and a first signal conversion circuit, the leakage current acquisition sensor is connected in parallel in a power supply circuit of the push rod body and outputs an acquisition signal OUT-flag to the first signal conversion circuit, and the first signal conversion circuit outputs two paths of signals including a forward rotation signal S1-TUI and a reverse rotation signal S1-HUI; and the power driving module comprises a second signal conversion circuit and a power driving circuit, the second signal conversion circuit converts the control signal RECTRL output by the CPU into a power driving signal, the power driving signal is transmitted to the power driving circuit, and the power driving circuit outputs a motor forward or reverse driving signal OUT + / OUT-to the push rod body. The mechanical action state of the push rod body is accurately recognized, and closed control of control-monitoring is formed.

Description

Technical Field

[0001] The present application belongs to the field of industrial control technology, and specifically relates to a system for realizing intelligent control and identification by utilizing an internal limit switch of an electric push rod. Background Art

[0002] Telescopic electric linear actuators are widely used in many fields such as home automation (electric windows, electric curtains), industrial automation (assembly lines, lifts), medical equipment (beds, operating tables) and agricultural equipment due to their versatility and high reliability, demonstrating their adaptability to various environments and needs.

[0003] There are many types of electric linear actuators, and their working principles and components are similar. Electric push-pull rods consist of an electric drive motor, a gear transmission structure, a push-pull rod body, and a limit sensor (two integrated internally). The drive motor often uses a DC motor. The push-pull rod can be extended and retracted by changing the positive and negative input voltage through an external drive power supply. The limit sensors at both ends serve to cut off the power supply.

[0004] like Figure 1 As shown, in actual use, the electric push rod has only two power lines, and the state information of the push rod cannot be detected. The commonly used solution is to add two limit switches externally (such as Figure 1 The actual installation position is on the pull rod body or the equipment where the push rod is installed, and is used to detect whether the stroke has reached the predetermined position.

[0005] like Figure 2 The internal electrical schematic diagram of the electric linear actuator shown in the figure shows the two arrows representing the external control power lines. When the two wiring harnesses are connected to voltage, the motor rotates, driving the actuator to extend and retract via a mechanical gear mechanism. The inherent characteristics of the electric linear actuator lead to the aforementioned complexity during use. This not only requires the installation of limit switches, but also increases the requirement for on-site wiring of the sensor harness. Since the sensors and harnesses are exposed, they also require regular inspection or replacement. This reduces the number of wiring connections in the upstream equipment and improves the integration of functional modules. From an economic perspective, this increases material and construction costs. Summary of the Invention

[0006] The present application provides a system for realizing intelligent control identification by utilizing the internal limit switch of an electric push rod, so as to solve or partially solve the problems raised in the above-mentioned background technology.

[0007] The present application provides a system for realizing intelligent control and identification by utilizing the internal limit switch of an electric push rod, comprising a CPU control module and a push rod body, wherein the CPU control module further comprises: a state feedback module and a power drive module;

[0008] The state feedback module includes a leakage current acquisition sensor and a first signal conversion circuit. The leakage current acquisition sensor is connected to the power circuit of the push rod body and outputs an acquisition signal OUT-flag to the first signal conversion circuit. The first signal conversion circuit outputs two signals, including a forward signal S1-TUI and a reverse signal S1-HUI.

[0009] The power drive module includes a second signal conversion circuit and a power drive circuit. The second signal conversion circuit converts the control signal RE_CTRL output by the CPU into a power drive signal. The power drive signal is transmitted to the power drive circuit. The power drive circuit outputs the motor forward or reverse drive signal OUT+ / OUT- to the push rod body.

[0010] Actuator body: realizes three-wire wiring mode and single signal line output of motor status detection signal.

[0011] Preferably, the leakage current collection sensor is connected to both ends of two limit switches in the power supply circuit of the push rod body, and the collection signal OUT-flag is output through a signal line;

[0012] The structure of the leakage current acquisition sensor is a parallel mode of two optical coupler sensors to identify the presence or absence of a signal and the direction of the signal.

[0013] Preferably, the first signal conversion circuit has two input signals, OUT-cai is connected to the motor reverse drive signal OUT-, OUT1-flag-HUI is connected to the motor feedback signal OUT-flag, and outputs two signals S1-TUI (forward) and S1-HUI (reverse), and the effective signal is a high level;

[0014] When the positive power supply is connected, it is found that there is current flowing from the signal line OUT1-flag-HUI through the leakage current collection sensor to the signal OUT-, the S1-TUI signal becomes low, and the S1-HUI signal remains high. This position change signal indicates that the push rod has been extended to the limit switch position, and this signal will remain.

[0015] Reverse the power supply polarity, that is, connect the negative power supply, and the push rod begins to retract. At this time, the current signal disappears, the S1-TUI signal becomes high, and the S1-HUI signal remains unchanged at a high level.

[0016] When the push rod continues to retract, current flows from the signal line OUT- through the leakage current collection sensor to the signal OUT1-flag-HUI, the S1-TUI signal remains unchanged and the S1-HUI signal becomes low. This position change signal indicates that the push rod has been retracted to the limit switch position, and this signal will remain.

[0017] Preferably, the method for identifying the push rod status through the two output signals S1-TUI and S1-HUI is as follows:

[0018] When the push rod is in motion, the signal status output is 11;

[0019] When the positive power supply is connected, the current flows from the positive pole of the power supply through the positive pole of the motor, passes through the No. 2 limit switch or the No. 2 diode, and then flows back to the negative pole of the power supply through the No. 1 limit switch, so that the motor rotates forward. At this time, there is no leakage current. When the No. 1 limit switch is opened, the motor is powered off, and the potential of the negative pole of the motor becomes high. A small leakage current is generated to the negative pole of the power supply through the sensor, and the current direction is toward the negative pole of the power supply. At this time, the sensor will output a position change signal, and the signal status output is 01.

[0020] When the reverse power supply is connected, the current flows from the positive electrode of the power supply through the negative electrode of the motor, passes through the No. 1 limit switch or the No. 1 diode, and then flows back to the negative electrode of the power supply through the No. 2 limit switch, realizing the motor reversal. At this time, there is no leakage current. When the No. 2 limit switch is opened, the motor is powered off, the potential of the negative electrode of the motor becomes low, and the positive electrode of the power supply generates a small leakage current to the negative electrode of the power supply through the sensor, and the current direction is toward the positive electrode of the power supply. At this time, the sensor will output a position change signal, and the signal status output is 10;

[0021] The signal status output 00 can be considered as the situation where both switches are opened at the same time. This situation should not occur in the actual working process. This status signal can be treated as a fault signal.

[0022] Preferably, the control signal RE_CTRL of the second signal conversion circuit can be a TTL signal with a level within 0-3.3V directly output by the processor CPU pin. The second signal conversion circuit is powered by an external 24V power supply. The control signal outputs a 24V1- drive signal after passing through the level conversion circuit and is directly connected to the relay coil input interface of the power drive circuit;

[0023] The power drive circuit has an input signal of 24VI- and an output signal of OUT+ / OUT- that is connected to the drive signal of the two-wire motor. The power drive circuit uses relay output, and a set of double-pole double-throw relays realizes the forward and reverse rotation of the motor by controlling the opening and closing.

[0024] Compared with the prior art, this application has the following beneficial effects:

[0025] (1) Through the design of the state feedback module and power drive module of the present application, the external intelligent control device can realize the on-off control of the high-power mechanical part of the push rod body, and realize the accurate identification of the mechanical action state of the push rod body, forming a control-monitoring closed control.

[0026] (2) This application utilizes the leakage current collection sensor and the two existing limit switches inside the electric push rod to collect the push rod status signal in real time. Only one signal line needs to be added. The modification is easy and the modification cost is low, which can achieve greater economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present application is further described below with reference to the accompanying drawings and examples.

[0028] Figure 1 It is a structural diagram of the existing electric push rod.

[0029] Figure 2 This is a schematic diagram of the existing push rod body power circuit.

[0030] Figure 3 Schematic diagram of the power supply circuit and three-wire wiring method of the actuator body designed and modified for this application,

[0031] Figure 4 This is a schematic diagram of the current flow in the power supply circuit of the push rod body when the motor rotates forward and reverse.

[0032] Figure 5 This is a schematic diagram of the system composition of this application.

[0033] Figure 6 This is a schematic diagram of the circuit principle of the state signal conversion circuit of this application.

[0034] Figure 7 This is a schematic diagram of the circuit principle of the second signal conversion circuit of this application.

[0035] Figure 8 This is a schematic diagram of the power drive circuit principle of this application.

[0036] Figure 9 This is a schematic diagram of the wiring terminals of this application.

[0037] Figure 10 This is a schematic diagram of the overall circuit principle of this application. DETAILED DESCRIPTION

[0038] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of the components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect.

[0039] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present application and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting the present application.

[0040] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0041] Example 1

[0042] like Figures 1 to 10 As shown, the present application provides a system for realizing intelligent control identification by using the internal limit switch of an electric push rod, comprising: a CPU control module and a push rod body, wherein the CPU control module further comprises a state feedback module and a power drive module, and the functions of each module are as follows;

[0043] CPU control module, including CPU and related control circuits;

[0044] The push rod body includes a push rod structure and a motor;

[0045] The state feedback module includes a leakage current acquisition sensor and a first signal conversion circuit. The leakage current acquisition sensor is connected to the power circuit of the push rod body and outputs an acquisition signal OUT-flag to the first signal conversion circuit. The first signal conversion circuit outputs two signals, including a forward signal S1-TUI and a reverse signal S1-HUI.

[0046] The power drive module includes a second signal conversion circuit and a power drive circuit. The second signal conversion circuit converts the control signal RE_CTRL output by the CPU into a power drive signal. The power drive signal is transmitted to the power drive circuit. The power drive circuit outputs the motor forward or reverse drive signal OUT+ / OUT- to the push rod body.

[0047] Specifically, the motor is a two-wire DC motor, and the design of this application implements a three-wire wiring method, thereby achieving a single signal line output of the motor status detection signal.

[0048] The design principle of this application is to collect the leakage current of the inductance coil of the push rod motor itself as the collection signal, and determine the open and close states of the two limit switches by confirming the direction of the leakage current, and then distinguish the position of the push rod.

[0049] like Figure 2 As shown in the figure, it is a schematic diagram of the power circuit of the push rod body of the original electric push rod. The two switches in the figure are the two limit switches inside the push rod body. Figure 3 As shown, in order to use the design of this application to transform the original power circuit, only one signal line needs to be added, that is, signal line No. 2 in the figure, as shown in FIG. Figure 4 The following are schematic diagrams of the current flow when the motor rotates forward and the push rod extends, and when the motor rotates reverse and the push rod retracts. The sensor in the figure is a leakage current collection sensor, which is connected to both ends of the two limit switches in the power circuit of the push rod body.

[0050] Figure 5 This is a schematic diagram of the system components of this application. The main control unit has three signal lines for the drive unit: one for output control and two for input status signals. The drive unit has three wiring harnesses for the push rod body: two for power drive and one for push rod status signal return.

[0051] The first signal conversion circuit has two input signals, OUT-cai is connected to the motor reverse drive signal OUT-, OUT1-flag-HUI is connected to the motor feedback signal OUT-flag, and the output signals are S1-TUI (forward) and S1-HUI (reverse), and the effective signal is high level.

[0052] The structure of the leakage current acquisition sensor is a two-way optical coupler sensor in parallel mode to identify the presence and direction of the signal, typically, such as Figure 6 The two optocoupler sensors S1 and S2 in the circuit.

[0053] Specifically, if Figure 6As shown, when the positive power supply is connected, it is found that current flows from the signal line OUT1-flag-HUI through the leakage current acquisition sensor to the signal OUT-, the S1-TUI signal becomes low, and the S1-HUI signal remains unchanged and high. This position change signal represents that the push rod has been extended to the limit switch position, and this signal will be maintained; the power supply polarity is reversed, that is, the negative power supply is connected, the push rod begins to retract, and the current signal disappears at this time, the S1-TUI signal becomes high, and the S1-HUI signal remains unchanged and high. When the push rod continues to retract, current flows from the signal line OUT- through the leakage current acquisition sensor to the signal OUT1-flag-HUI, the S1-TUI signal remains unchanged and high. The S1-HUI signal becomes low. This position change signal represents that the push rod has been retracted to the limit switch position, and this signal will be maintained. The signal line is directly connected to the terminal of the subsequent detection equipment, and the real-time action status of the motor can be detected in real time. The specific status representation is shown in Table 1.

[0054] Table 1

[0055] Signal name Push rod extended Push rod retracted Putting Fault status S1-TUI Low 0 High 1 High 1 Low 0 S1-HUI High 1 Low 0 High 1 Low 0

[0056] The push rod extension state and retraction state in Table 1 refer to the state when the push rod moves to the extension and retraction limits and triggers the two limit switches.

[0057] Specifically, when the push rod is in motion, the signal state is output 11.

[0058] When the positive power supply is connected, the current flows from the positive pole of the power supply through the positive pole of the motor, passes through the No. 2 limit switch or the No. 2 diode, and then flows back to the negative pole of the power supply through the No. 1 limit switch, so that the motor rotates forward (positive pole of the power supply). At this time, there is no leakage current. When the No. 1 limit switch is opened, the motor is powered off, and the potential of the negative pole of the motor becomes high. A small leakage current is generated to the negative pole of the power supply through the sensor, and the current direction is downward, that is, toward the negative pole of the power supply ( Figure 4 The sensor will output a displacement signal and the signal status will be 01.

[0059] When the reverse power supply is connected, the current flows from the positive pole of the power supply through the negative pole of the motor, passes through the No. 1 limit switch or the No. 1 diode, and then flows back to the negative pole of the power supply through the No. 2 limit switch to achieve motor reversal. At this time, there is no leakage current. When the No. 2 limit switch is opened, the motor is powered off, and the potential of the negative pole of the motor becomes low (the negative pole of the power supply). The positive pole of the power supply generates a small leakage current to the negative pole of the power supply through the sensor, and the current direction is upward, that is, toward the positive pole of the power supply ( Figure 5 The sensor will output a displacement signal, and the signal status output is 10.

[0060] The signal status output 00 can be considered as the situation where both switches are opened at the same time. This situation should not occur in the actual working process. This status signal can be treated as a fault signal.

[0061] like Figure 7 As shown, this is the second signal conversion circuit of the present application, which converts the weak voltage signal output by the CPU into the actual required level. For example, RE_CTRL can be a TTL signal with a level within 0-3.3V directly output by the processor CPU pin. The second signal conversion circuit is powered by an external 24V power supply. The control signal outputs a 24VI-drive signal after passing through the level conversion circuit, which is directly connected to the relay coil input interface of the power drive circuit, and the forward and reverse rotation of the motor is realized through the relay drive circuit.

[0062] like Figure 8 As shown, this is the power drive circuit of the present application. The input signal 24VI- and the output signal OUT+ / OUT- are connected to the drive signal of the two-wire motor. The power drive circuit adopts relay output. A set of double-pole double-throw relays (G2RL-24-DC24 in the figure) realizes the forward and reverse rotation of the motor by controlling the separation and combination.

[0063] Figure 9 This is a schematic diagram of the wiring terminals of this application, where P1 is the wiring terminal of the push rod body, and P2 is the wiring terminal of the intelligent identification control module composed of the state feedback module, power drive module, and CPU control module.

[0064] Figure 10 This is a schematic diagram of the circuit principle of the present application. As shown in the figure, through the design of the state feedback module and power drive module of the present application, the external intelligent control device can realize the switching control of the high-power mechanical part of the push rod body, and realize the accurate identification of the mechanical action state of the push rod body, forming a control-monitoring closed control.

[0065] The above describes the implementation methods of the present application in detail in conjunction with the accompanying drawings, but the present application is not limited to the above implementation methods. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A system for realizing intelligent control and identification by using the internal limit switch of an electric push rod, comprising a CPU control module and a push rod body, characterized in that: The CPU control module also includes: a state feedback module and a power drive module; The state feedback module includes a leakage current acquisition sensor and a first signal conversion circuit. The leakage current acquisition sensor is connected to the power circuit of the push rod body and outputs an acquisition signal OUT-flag to the first signal conversion circuit. The first signal conversion circuit outputs two signals, including a forward signal S1-TUI and a reverse signal S1-HUI. The power drive module includes a second signal conversion circuit and a power drive circuit. The second signal conversion circuit converts the control signal RE_CTRL output by the CPU into a power drive signal. The power drive signal is transmitted to the power drive circuit. The power drive circuit outputs the motor forward or reverse drive signal OUT+ / OUT- to the push rod body. Actuator body: realizes three-wire wiring mode and single signal line output of motor status detection signal.

2. The system for realizing intelligent control and identification by using the internal limit switch of the electric linear actuator according to claim 1, characterized in that: The leakage current collection sensor is connected to both ends of the two limit switches in the power circuit of the push rod body, and the collection signal OUT-flag is output through a signal line; The structure of the leakage current acquisition sensor is a parallel mode of two optical coupler sensors to identify the presence or absence of a signal and the direction of the signal.

3. The system for realizing intelligent control and identification by using the internal limit switch of the electric linear actuator according to claim 2, characterized in that: The first signal conversion circuit has two input signals, OUT-cai is connected to the motor reverse drive signal OUT-, OUT1-flag-HUI is connected to the motor feedback signal OUT-flag, and outputs two signals S1-TUI (forward) and S1-HUI (reverse), and the effective signal is high level; When the positive power supply is connected, current flows from the signal line OUT1-flag-HUI through the leakage current collection sensor to the signal OUT-, the S1-TUI signal becomes low, and the S1-HUI signal remains high. This position change signal indicates that the push rod has been extended to the limit switch position, and this signal will remain. When the negative power supply is connected, the push rod begins to retract, the current signal disappears, the S1-TUI signal becomes high, and the S1-HUI signal remains high; When the push rod continues to retract, current flows from the signal line OUT- through the leakage current collection sensor to the signal OUT1-flag-HUI, the S1-TUI signal remains high and the S1-HUI signal becomes low. This position change signal indicates that the push rod has been retracted to the limit switch position, and this signal will remain.

4. The system for realizing intelligent control and identification by using the internal limit switch of the electric linear actuator according to claim 3, characterized in that: The method of identifying the actuator status through the two output signals S1-TUI and S1-HUI is as follows: When the push rod is in motion, the signal status output is 11; When the positive power supply is connected, the current flows from the positive pole of the power supply through the positive pole of the motor, passes through the No. 2 limit switch or the No. 2 diode, and then flows back to the negative pole of the power supply through the No. 1 limit switch, so that the motor rotates forward. At this time, there is no leakage current. When the No. 1 limit switch is opened, the motor is powered off, and the potential of the negative pole of the motor becomes high. A small leakage current is generated to the negative pole of the power supply through the sensor, and the current direction is toward the negative pole of the power supply. At this time, the sensor will output a position change signal, and the signal status output is 01. When the reverse power supply is connected, the current flows from the positive electrode of the power supply through the negative electrode of the motor, passes through the No. 1 limit switch or the No. 1 diode, and then flows back to the negative electrode of the power supply through the No. 2 limit switch, realizing the motor reversal. At this time, there is no leakage current. When the No. 2 limit switch is opened, the motor is powered off, the potential of the negative electrode of the motor becomes low, and the positive electrode of the power supply generates a small leakage current to the negative electrode of the power supply through the sensor, and the current direction is toward the positive electrode of the power supply. At this time, the sensor will output a position change signal, and the signal status output is 10; The signal status output 00 can be considered as the situation where both switches are opened at the same time. This situation should not occur in the actual working process. This status signal can be treated as a fault signal.

5. The system for realizing intelligent control and identification by using the internal limit switch of the electric linear actuator according to claim 1, characterized in that: The control signal RE_CTRL of the second signal conversion circuit can be a TTL signal with a level within 0-3.3V directly output by the processor CPU pin. The second signal conversion circuit is powered by an external 24V power supply. The control signal outputs a 24V1- drive signal after passing through the level conversion circuit and is directly connected to the relay coil input interface of the power drive circuit; The power drive circuit has an input signal of 24VI- and an output signal of OUT+ / OUT- that is connected to the drive signal of the two-wire motor. The power drive circuit uses relay output, and a set of double-pole double-throw relays realizes the forward and reverse rotation of the motor by controlling the opening and closing.

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