A blade anti-collision control system

Abstract

The present invention discloses a blade anti-collision control system, comprising: a first controller, sending a control signal to a first driving mechanism; the first driving mechanism drives the first blade to move according to the control signal; a first position calculation module sends the actual position of the first blade to a planner; the planner outputs a position planning value to a second controller according to the received actual position of the first blade and the actual position of the second blade; the second controller sends a planning control signal to the second driving mechanism according to the position planning value; the second driving mechanism drives the second blade to move; and the second position calculation module sends the actual position of the second blade to the planner. The second controller of the blade anti-collision control system is designed based on the actual value of the first blade and the target difference between the two blades. Since the expected value of the second blade always includes the difference between the two blades, the control system can ensure the position difference between the two blades and prevent mutual collision between the blades.

Description

Technical Field

[0001] The present invention relates to the field of multi-leaf collimators, and in particular to a leaf anti-collision control system. Background Art

[0002] Multi-leaf collimators are usually in the treatment head structure, such as Figure 1 As shown, all blades are arranged in a blade box, and the blade box has a track for blade movement, in which the blades can slide. When the medical linear accelerator is in use, the blade box rotates together with the treatment head rotation system.

[0003] There are at least the following problems in the prior art:

[0004] Every two blades form a blade pair. If the two blades move independently according to the set value, the movement speed of blade 1 is significantly lower than that of blade 2. When approaching the target value, blade 1 decelerates faster or moves slightly slower, and blade 2 decelerates longer or moves slightly faster. The two blades will collide. Therefore, there is a possibility of collision in each blade pair.

[0005] Currently, no effective solution has been proposed for the problems in the prior art. Summary of the invention

[0006] The purpose of the present invention is to provide a blade anti-collision control system in view of the deficiencies in the prior art.

[0007] The blade anti-collision control system comprises: a first controller, a first drive mechanism, a first blade, a first ultrasonic sensor, a first position calculation module, a planner, a second controller, a second drive mechanism, a second blade, a second ultrasonic sensor and a second position calculation module;

[0008] The first controller is used to receive the first blade position expected value and send a control signal to the first driving mechanism according to the first blade position expected value;

[0009] The first driving mechanism drives the first blade to move according to the control signal;

[0010] The first ultrasonic sensor is used to detect the position of the first blade and send a first detection signal to the first position calculation module;

[0011] The first position calculation module calculates the actual position of the first blade according to the first detection signal, and sends the actual position of the first blade to the planner;

[0012] The planner outputs a position planning value to the second controller according to the received actual position of the first blade and the actual position of the second blade;

[0013] The second controller sends a planning control signal to the second driving mechanism according to the position planning value;

[0014] The second driving mechanism drives the second blade to move according to the planned control signal;

[0015] The second ultrasonic sensor is used to detect the second blade position and send a second detection signal to the second position calculation module;

[0016] The second position calculation module calculates the actual position of the second blade according to the second detection signal, and sends the actual position of the second blade to the planner.

[0017] Further, the planner determines the position planning value after making the following judgments based on the received actual position of the first blade and the actual position of the second blade;

[0018] If x2―x1<Δ, then the position planning value is x1+Δ;

[0019] If x2―x1≥Δ, the position planning value is the expected value of the second blade position;

[0020] Wherein, x1 is the actual position of the first blade, x2 is the actual position of the second blade, and Δ is the difference between the expected values ​​of the two blades.

[0021] Furthermore, the positions of the blade pairs are correlated, and a mathematical model is jointly set, and the expected position of the second blade is set to be the actual position of the first blade plus the expected position difference of the two blades.

[0022] Furthermore, the mathematical model of the blade pair is as follows:

[0023]

[0024]

[0025] In the formula, is the expected value of the first blade position, is the expected value of the second blade position, U1 and U2 are the first and second driving torques output by the first and second controllers, A1 and A2 are the first and second blade position coefficient constants; B1 and B2 are the coefficient constants of the first and second driving torques.

[0026] Furthermore, the control signal and the planned control signal sent by the first controller and the second controller are PWM waveforms of different widths respectively.

[0027] Furthermore, the first ultrasonic sensor and the second ultrasonic sensor emit ultrasonic waves through ultrasonic probes.

[0028] Further, the blade pair includes a first blade and a second blade.

[0029] Furthermore, the first blade is an active blade, and the second blade is a driven blade.

[0030] Furthermore, the first driving mechanism and the second driving mechanism both drive the mechanical transmission device through the rotation of the motor, thereby driving the first blade and the second blade to move.

[0031] Furthermore, the first blade and the second blade have the same structure.

[0032] Compared with the prior art, the blade anti-collision control system of the present invention has the following significant advantages:

[0033] 1. In the blade anti-collision control system of the present invention, the expected position of blade 2 takes the actual position of blade 1 and the sum of the expected difference between the two as the target value, so that blade 2 will refer to the position of blade 1 at any time. When the actual distance relative to the blade is less than the expected distance, a non-zero expected distance is always maintained therefrom. Because TPS cannot set a collision condition, this solution can effectively avoid collisions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a top view of the multi-leaf collimator;

[0035] Figure 2 It is a schematic structural diagram of the blade anti-collision control system of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0037] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0038] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0040] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0041] In addition, the terms "installed", "set", "provided with", "connected", "slidingly connected", "fixed", "clipped", and "set" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] In addition, the term "plurality" shall mean two or more.

[0043] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0044] like Figure 2As shown, the blade anti-collision control system includes: a first controller, a first drive mechanism, a first blade, a first ultrasonic sensor, a first position calculation module, a planner, a second controller, a second drive mechanism, a second blade, a second ultrasonic sensor, and a second position calculation module;

[0045] The first controller is used to receive the first blade position expected value and send a control signal to the first driving mechanism according to the first blade position expected value;

[0046] The first driving mechanism drives the first blade to move according to the control signal;

[0047] The first ultrasonic sensor is used to detect the position of the first blade and send a first detection signal to the first position calculation module;

[0048] The first position calculation module calculates the actual position of the first blade according to the first detection signal, and sends the actual position of the first blade to the planner;

[0049] The planner outputs a position planning value to the second controller according to the received actual position of the first blade and the actual position of the second blade;

[0050] The second controller sends a planning control signal to the second driving mechanism according to the position planning value;

[0051] The second driving mechanism drives the second blade to move according to the planned control signal;

[0052] The second ultrasonic sensor is used to detect the second blade position and send a second detection signal to the second position calculation module;

[0053] The second position calculation module calculates the actual position of the second blade according to the second detection signal, and sends the actual position of the second blade to the planner.

[0054] Further, the planner determines the position planning value after making the following judgments based on the received actual position of the first blade and the actual position of the second blade;

[0055] If x2―x1<Δ, then the position planning value is x1+Δ;

[0056] If x2―x1≥Δ, the position planning value is the expected value of the second blade position;

[0057] Wherein, x1 is the actual position of the first blade, x2 is the actual position of the second blade, and Δ is the difference between the expected values ​​of the two blades.

[0058] Furthermore, the positions of the blade pairs are correlated, and a mathematical model is jointly set, and the expected position of the second blade is set to be the actual position of the first blade plus the expected position difference of the two blades.

[0059] Furthermore, the mathematical model of the blade pair is as follows:

[0060]

[0061]

[0062] In the formula, is the expected value of the first blade position, is the expected value of the second blade position, U1 and U2 are the first and second driving torques output by the first and second controllers, A1 and A2 are the first and second blade position coefficient constants; B1 and B2 are the coefficient constants of the first and second driving torques.

[0063] Furthermore, the control signal and the planned control signal sent by the first controller and the second controller are PWM waveforms of different widths respectively.

[0064] Furthermore, the first ultrasonic sensor and the second ultrasonic sensor emit ultrasonic waves through ultrasonic probes.

[0065] Further, the blade pair includes a first blade and a second blade.

[0066] Specifically, the number of the blade pairs is several, and the blade pairs are arranged in sequence, and each blade pair includes two blades at the same height, which are a first blade and a second blade.

[0067] Furthermore, the first blade is an active blade, and the second blade is a driven blade.

[0068] Furthermore, the first driving mechanism and the second driving mechanism both drive the mechanical transmission device through the rotation of the motor, thereby driving the first blade and the second blade to move.

[0069] Furthermore, the first blade and the second blade have the same structure.

[0070] Specifically, the first blade and the second blade have the same structure and are arranged in relative positions.

[0071] Furthermore, assume that a set of relative blade positions [blade 1 blade 2] in TPS needs to move from [80 100] mm to [70 71] mm.

[0072] So the difference Δ in the expression is 1. Assuming that the blade is expected to move to the right position within 0.5s and the control cycle is 50ms, the setting value of blade 1 and blade 2 per cycle should be:

[0073] 1 2 3 4 5 6 7 8 9 10 Blade 1 79 78 77 76 75 74 73 72 71 70 Blade 2 97.1 94.2 91.3 88.4 85.5 82.6 79.7 76.8 73.9 71

[0074] As the processing power and communication methods are more advanced, the control cycle can be shorter, so the set value can be divided into finer parts. Due to the space limit, I will not repeat all the contents. Taking the control cycle of 10ms as an example, the last distance is subdivided as follows:

[0075] 1 2 3 4 5 Blade 1 70.8 70.6 70.4 70.2 70 Blade 2 73.32 72.74 72.16 71.58 71

[0076] It can be seen that the final targets of the two blades are very close. If the two blades move independently according to the set value, the movement speed of blade 1 is significantly lower than that of blade 2. When approaching the target value, blade 1 decelerates faster or moves slightly slower, and blade 2 decelerates for a longer time or moves slightly faster, and the two blades will collide. If continuous target following and facing conditions are considered, the possibility of collision caused by this independent control will increase when the distance between the blades is close.

[0077] With the solution in this paper, the target value of blade 2 is always at a certain distance from blade 1. If it is greater than the difference, it moves normally. If it is less than the difference, the distance between blade 2 and blade 1 remains at the difference. For example, blade 1 actually moves to 70.5 in the 4th cycle after subdivision, and blade 2 actually moves to 71.1. Compared with their respective set values, the error of the two blades is less than 0.5mm, which can be regarded as a relatively high control accuracy. However, blade 2 is faster than blade 1, and the braking distance of blade 2 is longer than that of blade 1. Moreover, the distance between the two is closer, which is 0.6mm. If the system settings are followed, there is still a possibility of collision between the two. At this time, the target value of blade 1 is still set to 70mm in the 5th cycle after subdivision, and the set value of blade 2 should be set to 71.5mm (the original set value is 71). Therefore, blade 2 can brake in advance and gradually decelerate to keep the same speed as blade 1 until the set value in TPS.

[0078] The working principle of the blade anti-collision control system described in the present invention is:

[0079] Each blade pair has the possibility of collision. If each blade is considered separately, the controlled variable is the position of each blade, assuming it is x, and the control variable is the driving torque, assuming it is U, then the spatial mathematical model of the blade pair is as follows:

[0080]

[0081] Where A and B are the coefficients of the controlled quantity and the control quantity respectively, which are constants.

[0082] In this scheme, the positions of the blade pairs are correlated, and their mathematical models are jointly set, with the first blade as the active blade and the second blade as the driven blade. The expected position of the second blade is set to the actual position of the first blade plus the expected position difference of the two blades. As shown in the following formula:

[0083]

[0084]

[0085] In the formula, is the expected value. Figure 2 As shown, the controller design of the second blade is obtained based on the actual value of the first blade and the target difference between the two blades. Since the expected value of the second blade always includes the difference between the two blades, the control system can ensure the position difference between the two blades, eliminating the possibility of collision between the blades from the control system design.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A blade anti-collision control system, characterized in that: include: A first controller, a first drive mechanism, a first blade, a first ultrasonic sensor, a first position calculation module, a planner, a second controller, a second drive mechanism, a second blade, a second ultrasonic sensor, and a second position calculation module; The first controller is used to receive the first blade position expected value and send a control signal to the first driving mechanism according to the first blade position expected value; The first driving mechanism drives the first blade to move according to the control signal; The first ultrasonic sensor is used to detect the position of the first blade and send a first detection signal to the first position calculation module; The first position calculation module calculates the actual position of the first blade according to the first detection signal, and sends the actual position of the first blade to the planner; The planner outputs a position planning value to the second controller according to the received actual position of the first blade and the actual position of the second blade; The second controller sends a planning control signal to the second driving mechanism according to the position planning value; The second driving mechanism drives the second blade to move according to the planned control signal; The second ultrasonic sensor is used to detect the second blade position and send a second detection signal to the second position calculation module; The second position calculation module calculates the actual position of the second blade according to the second detection signal, and sends the actual position of the second blade to the planner; The planner determines the position planning value after making the following judgments based on the received actual position of the first blade and the actual position of the second blade; If x2-x1<Δ, the position planning value is x1+Δ; If x2-x1≥Δ, the position planning value is the expected value of the second blade position; Where x1 is the actual position of the first blade, x2 is the actual position of the second blade, and Δ is the difference between the expected values ​​of the two blades; The positions of the blade pairs are correlated, and a mathematical model is jointly set, and the expected position of the second blade is set to the actual position of the first blade plus the expected position difference of the two blades; The mathematical model of the blade pair is as follows: In the formula, is the expected value of the first blade position, is the expected value of the second blade position, U1 and U2 are the first and second driving torques output by the first and second controllers, A1 and A2 are the first and second blade position coefficient constants; B1 and B2 are the coefficient constants of the first and second driving torques.

2. The blade anti-collision control system according to claim 1, characterized in that: The control signal and the planned control signal sent by the first controller and the second controller are PWM waveforms of different widths respectively.

3. The blade anti-collision control system according to claim 2, characterized in that: The first ultrasonic sensor and the second ultrasonic sensor emit ultrasonic waves through ultrasonic probes.

4. The blade anti-collision control system according to claim 3, characterized in that: The blade pair includes a first blade and a second blade.

5. The blade anti-collision control system according to claim 4, characterized in that: The first blade is an active blade, and the second blade is a driven blade.

6. The blade anti-collision control system according to claim 5, characterized in that: The first driving mechanism and the second driving mechanism both drive the mechanical transmission device through the rotation of the motor, thereby driving the first blade and the second blade to move.

7. The blade anti-collision control system according to claim 6, characterized in that: The first blade and the second blade have the same structure.

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