Track detection electric cylinder positioning control system and method

Abstract

The invention relates to a track detection electric cylinder positioning control system and method, and the system comprises an upper computer, a lower computer, an encoder, an inertial sensor, and an electric cylinder. The upper computer is used for sending a target track sequence to the lower computer so as to generate a target displacement amount of the electric cylinder in the lower computer; the electric cylinder is installed on the inertial sensor, and the inertial sensor is used for collecting an attitude angle signal of the electric cylinder and sending the attitude angle signal to the lower computer; the encoder is installed on the electric cylinder and used for collecting displacement signals and direction signals of the electric cylinder and sending the displacement signals and the direction signals to the lower computer. The lower computer is connected with a servo motor on the electric cylinder and used for calculating the compensation displacement of the electric cylinder according to the received target displacement, the received attitude angle signal, the received displacement signal and the received direction signal of the electric cylinder and generating a driving instruction used for driving the servo motor to rotate according to the compensation displacement. The method is used for solving the problems of low efficiency and low detection precision of a track detection vehicle during track transfer detection.

Description

Technical Field

[0001] The present invention relates to the technical field of track detection, and in particular to a track detection electric cylinder positioning control system and method. Background Art

[0002] Track inspection vehicles are special vehicles used to detect the geometric state and unevenness of tracks in order to evaluate the geometric state of tracks. They are divided into single-track inspection vehicles and multi-track inspection vehicles. Multi-track inspection vehicles are expensive and have poor flexibility. Currently, single-track inspection vehicles are mostly used. Most single-track inspection vehicles use fixedly installed cameras or sensors to achieve the track detection function. Their detection range is limited by the equipment position and it is difficult to achieve variable track detection. It is necessary to move the vehicle as a whole or modify the mechanical mechanism to adjust the position of the camera to achieve variable track detection. The traditional scheme has the problem of limited degrees of freedom. The camera cannot quickly adjust its detection range when the vehicle is stationary and is not suitable for variable track detection. Some install components such as cameras or sensors for detecting tracks on telescopic components such as electric cylinders or hydraulic cylinders, and adjust the position of the track detection sensor through the telescopic movement of the telescopic rod. Due to attitude changes such as pitching and yaw and the actual frictional resistance existing in the traditional telescopic component, there is a deviation between the actual displacement of the telescopic component and the theoretically calculated value, resulting in a large track detection error; it is also easy to have misalignment when changing the position of the track detection sensor, which is time-consuming and laborious and is prone to introducing manual errors, further resulting in a reduction in detection accuracy. Summary of the Invention

[0003] The purpose of the present invention is to provide a track detection electric cylinder positioning control system and method for improving the efficiency of variable track detection and maintaining a high detection accuracy.

[0004] In a first aspect, the present invention provides a track detection electric cylinder positioning control system, adopting the following technical solution: A track detection electric cylinder positioning control system includes a host computer, a slave computer, an encoder, an inertial sensor, and an electric cylinder; The host computer is used to send a target track sequence to the slave computer to generate a target displacement amount of the electric cylinder in the slave computer; The electric cylinder is installed on the inertial sensor, and the inertial sensor is used to collect the attitude angle signal of the electric cylinder and send it to the slave computer; The encoder is installed on the electric cylinder and is used to collect the displacement signal and direction signal of the electric cylinder and send them to the slave computer; The slave computer is connected to the servo motor on the electric cylinder and is used to calculate the compensation displacement amount of the electric cylinder according to the received target displacement amount, attitude angle signal, displacement signal, and direction signal of the electric cylinder, and generate a driving instruction for driving the rotation of the servo motor according to the compensation displacement amount.

[0005] A further technical solution lies in that the inertial sensor is connected with a Kalman filter. After the data collected by the inertial sensor is filtered by the Kalman filter, the attitude angles of the electric cylinder are calculated. The attitude angles of the electric cylinder include the pitch angle and the yaw angle.

[0006] A further technical solution lies in that the inertial sensor is internally provided with a temperature compensation gasket.

[0007] A further technical solution lies in that the lower computer includes a dynamic compensation unit and a control execution unit. Among them, the dynamic compensation unit is used to calculate the compensation displacement of the electric cylinder. The control execution unit includes a fuzzy PID controller and a PWM controller. The fuzzy PID controller generates a PWM duty cycle signal according to the compensation displacement, and the PWM controller generates a drive command for driving the servo motor to rotate according to the duty cycle signal.

[0008] A further technical solution lies in that the control execution unit further includes a Hall current sensor, which is used to collect the current signal of the servo motor, and calculate the gravity compensation torque of the servo motor through the PWM controller in combination with the pitch angle of the electric cylinder.

[0009] Compared with the prior art, a rail detection electric cylinder positioning control system provided by the present invention has the following beneficial effects: The present invention forms an intelligent compensation and closed-loop execution full-link collaborative processing solution through high-precision sensors such as IMU and encoders, overcomes the problem of low positioning accuracy of the electric cylinder caused by mechanical deformation, friction nonlinearity and dynamic disturbance in multi-rail detection, and provides an innovative solution for intelligent operation and maintenance of rail transit.

[0010] In the second aspect, the present invention provides a rail detection electric cylinder positioning control method, adopting the following technical solution: A rail detection electric cylinder positioning control method is applied to any one of the rail detection electric cylinder positioning control systems in the first aspect. The method includes: The upper computer sends a target track sequence to the lower computer, and the lower computer generates a target displacement L of the electric cylinder 目标 ; The encoder real-time collects the displacement signal of the electric cylinder and the direction signal , and sends them to the dynamic compensation unit. The inertial sensor real-time collects the three-axis acceleration and the three-axis angular velocity of the electric cylinder, calculates the pitch angle θ and the yaw angle φ of the electric cylinder through the Kalman filter, and sends them to the dynamic compensation unit; The dynamic compensation unit calculates the compensation length L of the electric cylinder according to the received pitch angle θ, yaw angle ϕ, displacement signal and direction signal , and sends the compensation length signal to the control execution unit; 补偿 The control execution unit generates a motor drive command according to the received compensation length signal L 补偿 and drives the servo motor to rotate.

[0011] Furthermore, the technical solution lies in that the dynamic compensation unit calculates the compensation length signal L of the electric cylinder according to the received pitch angle θ, yaw angle ϕ, displacement signal and direction signal , specifically including: 补偿 The dynamic compensation unit calculates the actual telescopic length of the electric cylinder according to the displacement signal , pitch angle θ and yaw angle φ of the electric cylinder L proj : ; Then, according to the actual telescopic length L proj , stiffness coefficient κ, friction coefficient μ, pitch angle θ, yaw angle ϕ, displacement signal and direction signal , the compensation length L of the electric cylinder is calculated 补偿 : .

[0012] Furthermore, the technical solution of the method further includes: The encoder feeds back the actual displacement L of the electric cylinder to the dynamic compensation unit in real time 实际 . If the error between the actual displacement and the target displacement is less than the set error threshold, that is, |L 实际 -L 目标 |<0.1mm, real-time compensation calculation is performed; If the error between the actual displacement and the target displacement exceeds the error threshold and continues for 3 times, switch to the IMU prediction mode: only rely on angular velocity integration to estimate displacement and maintain the basic positioning function; after the error returns within the error threshold, the encoder resynchronizes the count, the parameters of the dynamic compensation unit are reset, and the detection process continues to be executed.

[0013] Compared with the prior art, the beneficial effects of a method for positioning control of an electric cylinder for track detection provided by the present invention are the same as those of a positioning control system for an electric cylinder for track detection described in the first aspect, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a system block diagram provided by an embodiment of the present invention; Figure 2 It is a method flowchart provided by an embodiment of the present invention. Specific embodiments

[0015] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0017] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0018] In order to facilitate the clear description of the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the present invention should not be construed as being more preferred or more advantageous than other embodiments or design solutions. Exactly speaking, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific way.

[0019] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings of the specification.

[0020] Refer to Figure 1 , an embodiment of the present invention provides a track detection electric cylinder positioning control system, including a host computer, a slave computer, an encoder, an inertial sensor and an electric cylinder.

[0021] Among them, the host computer is used to send a target track sequence (such as track 1 → track 2 → track 3) to the slave computer to generate a target displacement amount of the electric cylinder in the slave computer.

[0022] The track detection sensor is installed on the electric cylinder, and the electric cylinder is equipped with a servo motor for controlling the extension or contraction of the electric cylinder, thereby realizing the adjustment of the position of the track detection sensor. The flange end of the cylinder body of the electric cylinder is installed on the inertial sensor. The inertial sensor collects the attitude angle signal of the electric cylinder and sends the attitude angle to the lower computer.

[0023] The inertial sensor is built-in with a six-axis MEMS sensor, including a three-axis accelerometer and a gyroscope, which synchronously collects the acceleration of the servo motor at a frequency of 1 kHz and the angular velocity .

[0024] Among them, the inertial sensor is built-in with a temperature compensation gasket. The temperature compensation gasket is a device used to eliminate the influence of temperature changes on the measurement results. When the ambient temperature changes, the linear expansion coefficient of the strain gauge is different from that of the measured component, resulting in the resistance value of the strain gauge changing with temperature, thus affecting the measurement accuracy. To eliminate this temperature influence, the bridge compensation method is usually adopted, that is, using a strain gauge with the same specifications, model, sensitivity coefficient and working piece as the temperature compensation piece, which is pasted on a specimen with the same material as the measured component but not stressed, or directly pasted on the non-stressed part of the measured component. During operation, the position of the compensation piece should be as close as possible to the measured working piece so that it is in the same temperature field. In this way, the temperature compensation piece can eliminate the influence of temperature changes on the measurement results of the working piece, thereby improving the measurement accuracy.

[0025] Furthermore, the inertial sensor is connected to a Kalman filter. The acceleration and angular velocity data collected by the inertial sensor are filtered by the Kalman filter, and then the attitude angle of the electric cylinder is calculated by the attitude calculation core unit on the inertial sensor; the attitude angle of the electric cylinder includes the pitch angle θ and the yaw angle ϕ. The angular velocity integral error correction signal of the inertial sensor is directly connected to the pulse compensation module on the encoder through the I²C bus to achieve the suppression of multi-sensor spatio-temporal synchronization errors.

[0026] The housing of the encoder is fixed to the flange end face of the servo motor by bolts, and the input shaft of the encoder is rigidly connected to the output shaft of the servo motor through a coupling for collecting the displacement signal and direction signal of the electric cylinder and sending them to the lower computer.

[0027] Specifically, when the servo motor drives the ball screw to rotate, the internal grating disk of the encoder rotates synchronously to generate orthogonal pulse signals (A / B phase). After passing through the quadruple-frequency logic circuit built into the encoder, the resolution is increased to 4000 pulses / turn. Combining with the displacement calculation core unit on the encoder, the displacement of the electric cylinder is calculated in real time. The phase difference (leading or lagging 90°) between the A-phase and B-phase pulses is used to determine the telescopic direction and output the direction flag , this signal is directly connected to the dynamic compensation unit of the lower computer through shielded twisted pair wires and participates in the friction correction term for the calculation, dynamically distinguishing the friction resistance differences between the extension and retraction of the electric cylinder.

[0028] The lower computer is connected to the servo motor on the electric cylinder. The lower computer calculates the compensation displacement of the electric cylinder based on the received target displacement amount, attitude angle signal, displacement signal, and direction signal of the electric cylinder, generates a drive command for driving the rotation of the servo motor according to the compensation displacement amount, and outputs it to the servo motor to position the electric cylinder.

[0029] Specifically, the lower computer includes a dynamic compensation unit and a control execution unit.

[0030] Among them, the dynamic compensation unit can be a computer, a microcontroller or a logic controller, and is used to calculate the compensation displacement of the electric cylinder. The dynamic compensation unit receives the displacement amount of the electric cylinder , displacement direction signal , pitch angle θ and yaw angle ϕ, and performs multi-physical field coupling calculation: First, correct the actual extended length of the electric cylinder through geometric projection , eliminating the displacement error caused by inclination; then superimpose the stiffness compensation term (suppressing bending deformation) and the yaw coupling term , and divide by the direction-sensitive friction term , and finally output the compensation displacement of the electric cylinder . If the deviation between the actual displacement amount feedback by the encoder and the target displacement amount is less than 0.1 mm, that is, |L 实际 - L 目标 | < 0.1 mm, then trigger the gradient descent algorithm to online update the stiffness coefficient κ and friction coefficient μ parameters of the electric cylinder to achieve model self-optimization.

[0031] For example, when the compensation displacement of the electric cylinder L 补偿 = 1200.5 mm, the controller rotates the servo motor 240.1 turns (the lead of the electric cylinder is 5 mm / turn). The encoder real-time checks the actual displacement of the electric cylinder. If the error between the actual displacement amount L of the electric cylinder 实际 and the target displacement amount L 目标 exceeds the limit, then control the servo motor to immediately reverse and fine-tune 0.005 turns (corresponding to the moving length of the electric cylinder being 0.025 mm). After the electric cylinder completes positioning, the control module switches to the retraction mode, and the direction signal triggers the friction coefficient μ to decrease by 40%. At the same time, the inertial sensor verifies that the attitude reset error |θ| is less than 0.3°, and the encoder zero error is less than 0.02 mm, establishing a benchmark for the next track detection.

[0032] The control execution unit includes a fuzzy PID controller and a PWM controller. The fuzzy PID controller can generate a PWM duty cycle signal according to the compensated displacement, and the PWM controller can generate a drive command for driving the servo motor to rotate based on the duty cycle signal, that is, output a space vector pulse width modulation waveform to drive the motor. An RC charge and discharge circuit is connected in parallel at the output end of the PWM controller, which can suppress the peak current at the moment when the servo motor starts.

[0033] The control execution unit further includes a Hall current sensor. The Hall current sensor is used to collect the current signal of the servo motor, and calculate the gravity compensation torque T of the servo motor through the PWM controller in combination with the pitch angle of the electric cylinder 补偿 and dynamically adjust the output torque of the servo motor through the space vector pulse width modulation waveform. Among them, the gravity compensation torque T of the servo motor 补偿 can be obtained by the following formula: .

[0034] Among them, k g is the weight of the electric cylinder bearing the track sensor, θ is the pitch angle of the electric cylinder.

[0035] Referring to Figure 2 , this embodiment also discloses a method for positioning control of an electric cylinder for track detection, which is applied to the above-mentioned positioning control system of an electric cylinder for track detection. The method includes the following steps: Step S1: The host computer sends a target track sequence to the slave computer, and the slave computer generates a target displacement L of the electric cylinder 目标 ; Step S2: The encoder continuously collects the displacement signal and the direction signal of the electric cylinder, and sends them to the dynamic compensation unit; the inertial sensor continuously collects the three-axis acceleration and the three-axis angular velocity of the electric cylinder, and calculates the pitch angle θ and yaw angle ϕ of the electric cylinder through the Kalman filter, and sends them to the dynamic compensation unit; Step S3: The dynamic compensation unit calculates the compensated displacement L of the electric cylinder according to the received pitch angle θ, yaw angle φ, displacement signal and direction signal of the electric cylinder, 补偿 and sends the compensated length signal to the control execution unit.

[0036] Among them, calculating the compensated displacement L of the electric cylinder 补偿 specifically includes: The dynamic compensation unit calculates according to the displacement signal of the electric cylinder , calculate the actual telescopic length of the electric cylinder based on the pitch angle θ and yaw angle ϕ L proj : ; Then, based on the actual telescopic length of the electric cylinder L proj , stiffness coefficient κ, friction coefficient μ, pitch angle θ, yaw angle ϕ, displacement signal and direction signal , calculate the compensation length L of the electric cylinder 补偿 : .

[0037] Step S4: Control the execution unit to generate a motor drive command according to the received compensation length signal L 补偿 and drive the servo motor to rotate.

[0038] Step S5: The encoder real-time feeds back the actual displacement L of the electric cylinder to the dynamic compensation unit 实际 , and judge whether the error between the actual displacement L 实际 and the target displacement L 目标 is less than the set error threshold; if so, that is, |L 实际 -L 目标 |<0.1mm, perform real-time compensation calculation, and at the same time trigger the gradient descent algorithm to update the stiffness coefficient κ and friction coefficient μ parameters online to achieve model self-optimization; if not and after 3 consecutive out-of-tolerance, switch to the IMU prediction mode; when the error returns within the error threshold, the encoder resynchronizes the count, the dynamic compensation model parameters are reset, and the detection process continues to be executed.

[0039] Among them, the IMU prediction mode is: only rely on angular velocity integration to estimate the displacement of the electric cylinder and maintain the basic positioning function of the electric cylinder. The specific principle is: perform time integration on the measured angular velocity to obtain the angular displacement, and then multiply by the radius to obtain the linear displacement.

[0040] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product.

[0041] Although the present invention has been described in connection with various embodiments, those skilled in the art will recognize other variations of the disclosed embodiments while practicing the claimed invention by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may implement several functions recited in the claims. Certain measures are recited in mutually different dependent claims, but this does not indicate that these measures cannot be combined to good effect.

[0042] Although the invention has been described in connection with specific features and embodiments thereof, it will be apparent that various modifications and combinations can be made without departing from the spirit and scope of the invention. Accordingly, the specification and drawings are merely exemplary illustrations of the invention defined by the appended claims and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. An electric cylinder positioning control system for track detection, characterized in that It includes a host computer, a slave computer, an encoder, an inertial sensor, and an electric cylinder; The host computer is used to send a target track sequence to the slave computer to generate a target displacement of the electric cylinder in the slave computer; The electric cylinder is installed on the inertial sensor, and the inertial sensor is used to collect the attitude angle signal of the electric cylinder and send it to the slave computer; The encoder is installed on the electric cylinder and is used to collect the displacement signal and direction signal of the electric cylinder and send them to the slave computer; The slave computer is connected to the servo motor on the electric cylinder and is used to calculate the compensation displacement of the electric cylinder according to the received target displacement, attitude angle signal, displacement signal, and direction signal of the electric cylinder, and generate a drive command for driving the rotation of the servo motor according to the compensation displacement.

2. The positioning control system of an electric cylinder for track detection according to claim 1, characterized in that, The inertial sensor is connected with a Kalman filter. After the data collected by the inertial sensor is filtered by the Kalman filter, the attitude angle of the electric cylinder is calculated; the attitude angle of the electric cylinder includes a pitch angle and a yaw angle.

3. The positioning control system of an electric cylinder for track detection according to claim 1, characterized in that The inertial sensor is internally provided with a temperature compensation gasket.

4. The positioning control system of an orbital inspection electric cylinder according to claim 2, characterized in that, The slave computer includes a dynamic compensation unit and a control execution unit; wherein, the dynamic compensation unit is used to calculate the compensation displacement of the electric cylinder; the control execution unit includes a fuzzy PID controller and a PWM controller. The fuzzy PID controller generates a PWM duty cycle signal according to the compensation displacement, and the PWM controller generates a drive command for driving the rotation of the servo motor according to the duty cycle signal.

5. The positioning control system of an electric cylinder for track detection according to claim 4, characterized in that, The control execution unit further includes a Hall current sensor, and the Hall current sensor is used to collect the current signal of the servo motor and calculate the gravity compensation torque of the servo motor through the PWM controller in combination with the pitch angle of the electric cylinder.

6. A positioning control method for an electric cylinder in track detection, which is applied to a positioning control system for an electric cylinder in track detection according to any one of claims 1 to 5, characterized in that, The method includes: The host computer sends the target track sequence to the slave computer, and the target displacement L of the electric cylinder is generated in the slave computer 目标 ; The encoder real-time collects the displacement signal of the electric cylinder and the direction signal , and sends them to the dynamic compensation unit; the inertial sensor real-time collects the three-axis acceleration and the three-axis angular velocity of the electric cylinder, calculates the pitch angle θ and yaw angle φ of the electric cylinder through the Kalman filter, and sends them to the dynamic compensation unit; The dynamic compensation unit calculates the compensation length L of the electric cylinder based on the received pitch angle θ, yaw angle φ, displacement signal and direction signal , and sends the compensation length signal to the control execution unit; 补偿 ​ The control execution unit generates a motor drive command according to the received compensation length signal L 补偿 and drives the servo motor to rotate.

7. A method for positioning control of an orbital inspection electric cylinder according to claim 6, characterized in that, The dynamic compensation unit calculates the compensation length signal L of the electric cylinder according to the received pitch angle θ, yaw angle φ, displacement signal and direction signal , and specifically includes: 补偿 ​ The dynamic compensation unit calculates the actual telescopic length of the electric cylinder based on the displacement signal of the electric cylinder 、the pitch angle θ and the yaw angle φ L proj : ； Then, according to the actual telescopic length of the electric cylinder L proj , stiffness coefficient κ, friction coefficient μ, pitch angle θ, yaw angle φ, displacement signal and direction signal , calculate the compensation length L of the electric cylinder 补偿 : 。 8. A positioning control method for an electric cylinder for track detection according to claim 6, characterized in that, The method further includes: The encoder feeds back the actual displacement L of the electric cylinder to the dynamic compensation unit in real time 实际 , if the error between the actual displacement and the target displacement is less than the set error threshold, that is , perform real-time compensation calculation; If the error between the actual displacement and the target displacement exceeds the error threshold and after 3 consecutive times, switch to the IMU prediction mode. When the error returns within the error threshold, the encoder resynchronizes the count, the dynamic compensation model parameters are reset, and the detection process continues; wherein, the IMU prediction mode is: only relying on the integration of angular velocity to estimate the displacement of the electric cylinder and maintaining the basic positioning function of the electric cylinder.

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