CN203896236U - An automatic multi-leaf collimator leaf precise control structure - Google Patents

Abstract

The utility model discloses an automatic multi-leaf collimator blade precision control structure, comprising: a servo motor driving the blades on a rotating shaft to rotate; an encoder for detecting the rotation speed of the servo motor; a position detection circuit for detecting the initial position of the blade; a motor drive control circuit connected to the encoder and the position detection circuit, used to receive blade motion setting data, and generate a motor control signal according to the blade motion setting data, the rotation speed of the servo motor and the initial position of the blade; and a motor drive circuit connected to the motor drive control circuit and the servo motor, used to amplify the motor control signal and drive the servo motor to rotate; the utility model improves the movement speed and the movement position accuracy of the automatic collimator blade, reduces the control error, adopts hardware circuit design, and avoids the problem of occupying resources by adopting computer real-time control.

Description

An automatic multi-leaf collimator leaf precise control structure

technical field

The utility model relates to the technical field of tumor precision radiotherapy, in particular to an automatic multi-leaf collimator blade precise control structure.

Background technique

The multi-leaf collimator is an electromechanical integration device composed of an electronic control circuit, a mechanical drive device, and two groups of symmetrically arranged grating blades. By controlling the drive system of the grating, the blades move forward and backward to form a field window of any shape; the radiation only irradiates the tumor target area through the window, and the intensity of the radiation outside the window will be attenuated due to the shielding of the blades. To ensure that the degree of damage to normal tissues is minimized to achieve the purpose of treating tumors and protecting normal tissues, multi-leaf collimators play a very important role in modern radiation therapy equipment.

At present, the control method for the blades of the multi-leaf collimator in the prior art is mainly completed by a computer. The computer calculates the number of revolutions of the motor according to the output signal of the encoder, and then calculates the forward or backward distance of the collimator blades. Therefore, the position of the blade is calculated, which is actually a semi-closed-loop control method, which has a large error in adjusting the speed and position of the blade, and takes up a lot of computer resources.

Contents of the invention

The utility model aims at the above problems, and develops an automatic multi-leaf collimator blade precise control structure.

The technical scheme of the utility model is:

An automatic multi-leaf collimator leaf precise control structure, including:

A servo motor that drives the blades on the rotating shaft to rotate;

An encoder for detecting the rotational speed of the servo motor;

a position detection circuit for detecting the initial position of the blade;

Connecting the encoder and the position detection circuit, a motor drive control circuit for receiving blade motion setting data, and generating a motor control signal according to the blade motion setting data, the servo motor speed and the initial position of the blade;

Connecting the motor drive control circuit and the servo motor, the motor drive circuit used to amplify the motor control signal and drive the servo motor to rotate;

And connect the servo motor, encoder, position detection circuit, motor drive control circuit and motor drive circuit, for providing the power supply VCC of working power to the servo motor, encoder, position detection circuit, motor drive control circuit and motor drive circuit ;

Further, the position detection circuit includes:

Optical fiber sensor, resistor R4, resistor R5, voltage regulator tube D3, voltage regulator tube D4, six inverters U4A and six inverter U4B used to detect the initial position of the blade; the output end of the fiber optic sensor is connected to the The input end of the six inverters U4A; the output end of the optical fiber sensor is connected to a 12V power supply through a resistor R4; the voltage stabilizing diode D3 is connected in parallel between the power supply VCC and the input end of the six inverters U4A; The voltage diode D4 is connected in parallel between the input terminal of the six inverter U4B and the ground; the output terminal of the six inverter U4A is connected to the input terminal of the six inverter U4B; the six inverter U4B The output terminal is used as the output terminal of the position detection circuit;

Further, the motor drive control circuit includes a motor-specific motion controller chip U1; the pins D0-D7 of the motor-specific motion controller chip U1 are used to receive blade motion setting data; the motor-specific motion controller chip pins of U1 It is connected with the output end of the position detection circuit; the pin A and pin B of the special motion controller chip U1 of the motor are connected to the output end of the encoder; the pin PWMS of the special motion controller chip U1 of the motor is and pin PWMM as the output end of the motor drive control circuit;

Additionally, include:

A buffer U3B whose input end is connected to the pin PWMS of the motor-specific motion controller chip U1;

A buffer U3A whose input end is connected to the pin PWMM of the motor-specific motion controller chip U1;

The motor drive circuit includes a motor driver chip U2, a resistor R2, a resistor R30, a capacitor C24, a capacitor C17 and a capacitor C28; the pin CP of the motor driver chip U2 is connected to a 12V power supply through a capacitor C17; the capacitor C24 is connected to the Between the pin CP2 and the pin CP1 of the motor driver chip U2; the pin PHASE of the motor driver chip U2 is connected to the output end of the buffer U3B; the pin Rosc of the motor driver chip U2 is grounded through a resistor R2 The pin ENABLE of the motor driver chip U2 is connected to the output end of the buffer U3A; the pin OUTA of the motor driver chip U2 is connected to the positive pole of the servo motor; the pin of the motor driver chip U2 OUTB is connected to the negative pole of the servo motor; the pin SENSE of the motor driver chip U2 is grounded through a resistor R30 and a capacitor C28 connected in parallel;

Further, the motor-specific motion controller U1 adopts LM629;

Further, the motor driver chip U2 adopts A3959;

Further, the encoder is an incremental photoelectric encoder.

Due to the adoption of the above technical scheme, the utility model provides a precise control structure for the blades of the automatic multi-leaf collimator. The utility model detects the servo motor speed through the encoder and feeds it back to the motor drive control circuit, and detects the initial position of the blade through the position detection circuit. Feedback to the motor drive control circuit, the motor drive control circuit generates motor control signals according to the blade motion setting data, combined with the detected servo motor speed and blade initial position, and constitutes the motor speed closed control and blade position closed loop control, thereby improving The accuracy of the movement speed and movement position of the autocollimator blades reduces the control error, and the hardware circuit design is adopted to avoid the problem of resource occupation by computer real-time control.

Description of drawings

Fig. 1 is a schematic circuit diagram of the utility model;

FIG. 2 is a curve diagram of the trapezoidal contour trajectory generated by the motor-specific motion controller chip U1 of the present invention.

Detailed ways

A kind of automatic multi-leaf collimator blade precise control structure as shown in Figure 1, comprises: the servomotor that drives described blade on the rotating shaft to rotate; The encoder that is used to detect described servomotor rotating speed; The position detection circuit of the initial position of the blade; connecting the encoder and the position detection circuit, used to receive the blade motion setting data, and generate a motor control signal according to the blade motion setting data, the servo motor speed and the blade initial position Drive control circuit; connect the motor drive control circuit and the servo motor, the motor drive circuit used to amplify the motor control signal and drive the servo motor to rotate; and connect the servo motor, encoder, position detection circuit, motor drive control circuit and motor The drive circuit is used to provide the power supply VCC of the working power supply to the servo motor, the encoder, the position detection circuit, the motor drive control circuit and the motor drive circuit; further, the position detection circuit includes: used to detect the initial position of the blade Optical fiber sensor, resistor R4, resistor R5, voltage regulator tube D3, voltage regulator tube D4, six phase inverters U4A and six phase inverters U4B; the output end of the optical fiber sensor is connected to the input of the six phase inverters U4A through resistor R5 terminal; the output end of the optical fiber sensor is connected to a 12V power supply through a resistor R4; the Zener diode D3 is connected in parallel between the power supply VCC and the input end of the six inverters U4A; the Zener diode D4 is connected in parallel between the Between the input terminal of the six inverter U4B and the ground; the output terminal of the six inverter U4A is connected to the input terminal of the six inverter U4B; the output terminal of the six inverter U4B is used as the position The output end of the detection circuit; further, the motor drive control circuit includes a motor-specific motion controller chip U1; the pins D0-D7 of the motor-specific motion controller chip U1 are used to receive blade motion setting data; the The pins of the motor-specific motion controller chip U1 It is connected with the output end of the position detection circuit; the pin A and pin B of the special motion controller chip U1 of the motor are connected to the output end of the encoder; the pin PWMS of the special motion controller chip U1 of the motor is and pin PWMM as the output end of the motor drive control circuit; in addition, it also includes: a buffer U3B whose input end is connected to the pin PWMS of the motor-specific motion controller chip U1; A buffer U3A connected to the pin PWMM of the motion controller chip U1; the motor drive circuit includes a motor driver chip U2, a resistor R2, a resistor R30, a capacitor C24, a capacitor C17 and a capacitor C28; the lead of the motor driver chip U2 The pin CP is connected to the 12V power supply through the capacitor C17; the capacitor C24 is connected between the pin CP2 and the pin CP1 of the motor driver chip U2; the pin PHASE of the motor driver chip U2 is connected to the output of the buffer U3B terminal; the pin Rosc of the motor driver chip U2 is grounded through the resistor R2; the pin ENABLE of the motor driver chip U2 is connected to the output end of the buffer U3A; the pin OUTA of the motor driver chip U2 is connected The positive pole of the servo motor; the pin OUTB of the motor driver chip U2 is connected to the negative pole of the servo motor; the pin SENSE of the motor driver chip U2 is grounded through the resistor R30 and the capacitor C28 connected in parallel; further, the The motor-specific motion controller U1 uses LM629; further, the motor driver chip U2 uses A3959; further, the encoder uses an incremental photoelectric encoder.

The blade precision control structure of the utility model also includes: an RS485 interface circuit for receiving blade motion setting data through the RS485 interface; a circuit connected to the RS485 interface for sending the blade motion setting data to the motor drive control circuit Host computer; the blade motion setting data includes blade target position, blade maximum speed and acceleration; the encoder uses an incremental photoelectric encoder, which feeds back the rotation of the servo motor to the motor-specific motion controller chip Pin A and pin B of U1; the optical fiber sensor is installed at the end of the blade to detect the position corresponding to the zero point of the collimator blade. When the collimator blade triggers the optical fiber sensor, the position detection circuit outputs a position signal for transmission To the pin of the motor-specific motion controller chip U1 The motor-specific motion controller chip U1 records this position as the reference zero point of future motion, that is, the initial position. The motor-specific motion controller chip U1 adopts LM629, which is a dedicated motion control processor for full digital control. Position, speed and acceleration registers, programmable digital PID controller, command and position generator, position feedback processor, and encoder interface, etc., can set data such as blade target position, blade maximum speed and Acceleration, etc., combined with the speed data of the servo motor and the initial position data of the blade to calculate the required trapezoidal contour trajectory graph and the motor control signal corresponding to the trajectory graph; specifically, the motor-specific motion controller chip U1 outputs the position detection circuit The position signal is used as the starting position, combined with the target position in the blade motion setting data, and according to the current speed of the servo motor, the set blade speed and acceleration, the trajectory graph shown in Figure 2 is internally generated and the corresponding Motor control signal, wherein v represents the blade speed, t represents the time, p1 represents the initial position of the blade, and p2 represents the target position of the blade. This part of the function is the internal integration function of the existing motor-specific motion controller chip U1; the motor control signal includes The PWM signal and the motor rotation direction signal, the motor control signal is shaped and filtered by the buffer U3A and the buffer U3B, and output to the motor drive circuit to amplify the power of the motor control signal, and the motor drive circuit outputs the amplified motor control signal The signal drives the servo motor to rotate, and then drives the blade to move; the pin SENSE of the motor driver chip U2 is grounded through the parallel resistor R30 and capacitor C28, which acts as a current limiter and protects the motor dedicated motion controller chip U1.

The utility model detects the rotational speed of the servo motor through an encoder and feeds it back to the motor drive control circuit, detects the initial position of the blade through the position detection circuit and feeds it back to the motor drive control circuit, and the motor drive control circuit sets the data according to the motion of the blade, combined with the detected servo motor The rotational speed and the initial position of the blades generate motor control signals, which constitute the closed-loop control of the motor speed and the closed-loop control of the blade position, thereby improving the accuracy of the motion speed and motion position of the blades of the automatic multi-leaf collimator, reducing control errors, and adopting hardware circuits The design avoids the problem of using computer real-time control to occupy resources; the utility model takes the digitally controlled motor drive controller chip as the core, and completes the precise control of the blades of the automatic multi-leaf collimator. The overall design and structure are simple and free The software resources occupied by the control method of the prior art can be realized, and the blades of the automatic multi-leaf collimator can reach the expected set position at a reasonable speed, which increases the stability of the blade movement, and provides a better solution for the implementation of four-dimensional radiotherapy. The collimator blade control scheme; the utility model is a scientific research achievement funded by the National International Science and Technology Cooperation Special Fund (2012DFA10700).

The above is only a preferred embodiment of the utility model, but the scope of protection of the utility model is not limited thereto. Any equivalent replacement or change of the new technical solution and its inventive concept shall be covered by the protection scope of the present utility model.

Claims (7)

1. the accurate control structure of automatic multi-diaphragm collimator blade, is characterized in that comprising:

Drive the servomotor of the described blade rotation in rotating shaft;

For detection of the encoder of described servomotor rotating speed;

For detection of the position detecting circuit of described blade initial position;

Connect described encoder and described position detecting circuit, for receiving blade movement setting data, and according to the motor driving controling circuit of blade movement setting data, servomotor rotating speed and blade initial position generation motor control signal;

Connect motor driving controling circuit and servomotor, for the motor-drive circuit that described motor control signal is amplified and drive servomotor to rotate;

And connect servomotor, encoder, position detecting circuit, motor driving controling circuit and motor-drive circuit, for the power supply VCC of working power being provided to described servomotor, encoder, position detecting circuit, motor driving controling circuit and motor-drive circuit.

2. the accurate control structure of a kind of automatic multi-diaphragm collimator blade according to claim 1, is characterized in that described position detecting circuit comprises:

For detection of Fibre Optical Sensor, resistance R 4, resistance R 5, voltage-stabiliser tube D3, voltage-stabiliser tube D4, six phase inverter U4A and the six phase inverter U4B of blade initial position; Described Fibre Optical Sensor output connects the input of described six phase inverter U4A by resistance R 5; Described Fibre Optical Sensor output connects 12V power supply by resistance R 4; Described voltage stabilizing didoe D3 and be connected in power supply VCC and the input of described six phase inverter U4A between; Described voltage stabilizing didoe D4 is also connected between the input and ground of described six phase inverter U4B; The output of described six phase inverter U4A connects the input of described six phase inverter U4B; The output of described six phase inverter U4B is as the output of described position detecting circuit.

3. the accurate control structure of a kind of automatic multi-diaphragm collimator blade according to claim 1, is characterized in that described motor driving controling circuit comprises motor special motion controller chip U1; Pin D0～D7 of described motor special motion controller chip U1 is used for receiving blade movement setting data; The pin of described motor special motion controller chip U1 be connected with described position detecting circuit output; The pin A of described motor special motion controller chip U1 is connected the output of described encoder with pin B; The pin PWMS of described motor special motion controller chip U1 and pin PWMM are as the output of described motor driving controling circuit.

4. the accurate control structure of a kind of automatic multi-diaphragm collimator blade according to claim 3, characterized by further comprising:

The buffer U3B that input is connected with the pin PWMS of described motor special motion controller chip U1;

The buffer U3A that input is connected with the pin PWMM of described motor special motion controller chip U1;

Described motor-drive circuit comprises motor driver chip U2, resistance R 2, resistance R 30, capacitor C 24, capacitor C 17 and capacitor C 28; The pin CP of described motor driver chip U2 connects 12V power supply by capacitor C 17; Described capacitor C 24 is connected between the pin CP2 and pin CP1 of described motor driver chip U2; The pin PHASE of described motor driver chip U2 connects the output of described buffer U3B; The pin Rosc of described motor driver chip U2 is by resistance R 2 ground connection; The pin ENABLE of described motor driver chip U2 is connected with the output of described buffer U3A; The pin OUTA of described motor driver chip U2 connects the positive pole of described servomotor; The pin OUTB of described motor driver chip U2 connects the negative pole of described servomotor; The pin SENSE of described motor driver chip U2 is by resistance R parallel with one another 30 and capacitor C 28 ground connection.

5. the accurate control structure of a kind of automatic multi-diaphragm collimator blade according to claim 3, is characterized in that described motor special motion controller U1 adopts LM629.

6. the accurate control structure of a kind of automatic multi-diaphragm collimator blade according to claim 4, is characterized in that described motor driver chip U2 adopts A3959.

7. the accurate control structure of a kind of automatic multi-diaphragm collimator blade according to claim 1, is characterized in that described encoder adopts incremental optical-electricity encoder.