Radiation-resistant mechanical arm based on rear system and control method thereof

Abstract

The invention discloses a radiation-resistant mechanical arm based on a postposition system and a control method thereof, and solves the technical problem that a conventional mechanical arm in a nuclear waste post-treatment hot chamber system is exposed in an ionizing radiation field for a long time due to the fact that materials and electronic components of the conventional mechanical arm are not specially reinforced aiming at a radiation environment, so that the function of the mechanical arm is failed. According to the mechanical arm, the driver most sensitive to radiation is placed in the non-radiation area and connected with the n-path multiplexing switch through the power cable, the driver is systematically arranged at the back, the radiation resistance of the mechanical arm is achieved, and it can be guaranteed that the mechanical arm can normally work for a long time in the radiation environment; according to the control method, the joint motors can be controlled to move at the same time in the process, so that the overall efficiency of the mechanical arm is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a mechanical arm and a control method thereof, in particular to a radiation-resistant mechanical arm based on system postposition and a control method thereof. BACKGROUND

[0002] In the field of nuclear power and nuclear waste reprocessing, the hot cell is a key facility for remote operation and treatment of high radioactivity substances. Generally, the hot cell and its directly connected process operation area are designated as a radiation area, while the conventional maintenance hall, main control room, office area, etc. are divided into a non-radiation area. In order to effectively prevent the spread of radioactive substances, the radiation area and the non-radiation area are isolated by multiple physical shields (such as thick concrete walls, heavy metal doors), strict zoning management and negative pressure ventilation system; the core of the layout design of the negative pressure ventilation system is air flow organization, which ensures that air always flows from the non-radiation area (low pollution) to the radiation area (high pollution area), and is finally discharged after high-efficiency filtration, so as to prevent the spread of radioactive aerosols. The radiation area is usually provided with a sanitary outlet and an inlet, and personnel entering and leaving must go through procedures such as changing clothes, contamination monitoring and dose recording.

[0003] The internal radiation area is further finely divided into various sub-areas according to the dose rate level, such as green area, yellow area, orange area, red area, etc., and there are clear physical boundaries and access control between each sub-area; the non-radiation area varies greatly according to the specific design of the plant, the layout of the equipment and the shielding requirements, but the key is the thickness and structure of the shielding body, rather than simply the spatial distance, to ensure that the radiation level of adjacent non-radiation areas meets the safety standards, so that the radiation protection of the entire plant can minimize the harm and pollution risk to personnel.

[0004] However, in the existing nuclear waste reprocessing hot cell system, there is a key technical bottleneck: conventional mechanical arms cannot operate stably in a high-intensity radiation environment for a long time. At present, most facilities still use ordinary industrial mechanical arms or simplified remote operation, but because the materials and electronic components are not specially reinforced for the radiation environment, they are damaged due to long-term exposure to ionizing radiation fields, which in turn causes the mechanical arm to fail. SUMMARY

[0005] The purpose of the present application is to solve the technical problem that the conventional mechanical arm in the nuclear waste reprocessing hot cell system is damaged due to long-term exposure to ionizing radiation fields because the materials and electronic components are not specially reinforced for the radiation environment, which in turn causes the mechanical arm to fail, and to provide a radiation-resistant mechanical arm based on system postposition and a control method thereof.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions: The application discloses a radiation-resistant mechanical arm based on system postpositioning, which comprises a mechanical arm body arranged in a radiation area, and has the specialities that: Further, the application also provides a control method of the radiation-resistant mechanical arm based on system postpositioning, which has the specialities that the method comprises the following steps: The application further comprises a driver, an n-way multiplex switch, n control switches, n joint motors and a processor, wherein n is greater than or equal to 3. The processor is used to generate a time-sequenced joint motor motion list according to a task plan and a target position. The driver is arranged in a non-radiation area and is internally provided with a multi-motor cooperative control algorithm and a dynamic coupling observation algorithm. The output end of the driver is connected with the input end of the n-way multiplex switch through a power cable. The n power output ends of the n-way multiplex switch are respectively connected with the power input ends of the n control switches.

[0007] The n signal control ends of the n-way multiplex switch are connected with the signal receiving ends of the n control switches. The n-way multiplex switch is used to receive the motor driving signals and send control instructions to the corresponding control switches. The output ends of the n control switches are respectively connected with the input ends of the n joint motors. The joint motors are arranged at the joints of the mechanical arm body. The control switches are used to control the joint motors to move the mechanical arm body according to the control instructions.

[0008] Further, the step 1 is specifically as follows: Based on the kinematics model of the robot arm and the task planning, the overall motion task of the robot arm is decomposed into cooperative sub-tasks of the joint motors according to the joint degrees of freedom, and the timing relationship and cooperation constraints between the sub-tasks are determined.

[0009] Further, in step 2, the motion sequence of the joint motor includes the angle, angular velocity and torque command sequence of the joint motor.

[0010] Further, step 2 is specifically: Set the target position of the robot arm, calculate the expected motion path of the robot arm end through the trajectory planning algorithm, and map the expected motion path of the robot arm end to multiple groups of motion sequences of the joint motor according to the inverse kinematics model.

[0011] Further, in step 2, the trajectory planning algorithm is a spline interpolation algorithm or a polynomial trajectory generation algorithm.

[0012] Further, step 3 is specifically: Step 3.1, according to the timing relationship between the sub-tasks, rearrange the motion sequence of each group of joint motors in the time scale, take the physical limit of each joint motor motion and the cooperation constraint between each sub-task as the constraint condition, take the minimization of the total motion time or the total energy consumption as the target, and use the optimization algorithm to optimize the motion sequence of each joint motor after rearrangement. The motion sequence of the multiple groups of optimal joint motors is obtained, and the motion sequence of the multiple groups of optimal joint motors is sorted according to the total motion time or the total energy consumption from small to large; Step 3.2, using a conflict detection algorithm, the motion sequence of a group of excellent joint motors is detected according to the sorting mechanical interference or dynamics conflict, if mechanical interference or dynamics conflict occurs, the mechanical interference or dynamics conflict detection of the next group of motion sequences is carried out, otherwise, the motion sequence of each joint motor in the current group of robot arms is determined as the optimal motion sequence; Step 3.3, according to the optimal motion sequence, a time-ordered joint motor motion list is generated.

[0013] Further, in step 3.1, the optimization algorithm is a dynamic programming algorithm or a genetic algorithm; In step 3.2, the conflict detection algorithm includes a joint space-based motion interference detection method or a task space-based motion interference detection method.

[0014] Further, step 4 is specifically: The joint motor movement list is input into the driver, parallel control calculation of the joint motor movement list is carried out through a multi-motor cooperative control algorithm, interaction force estimation and compensation among the joint motors are calculated through a real-time dynamic coupling observation algorithm, corresponding motor driving signals are generated, the n-way multiplexing switch sends control instructions to the n control switches according to the motor driving signals, and the corresponding joint motor is controlled to move, so that the mechanical arm body is moved in the same or coordinated manner in the same time period.

[0015] The present application has the following advantages: 1. The present application provides a radiation-resistant mechanical arm based on system postpositioning, which places the most radiation-sensitive driver in a non-radiation area and connects the n-way multiplexing switch through a power cable to realize system postpositioning of the driver, thereby realizing the radiation-resistant performance of the mechanical arm and ensuring that the mechanical arm can work normally for a long time in a radiation environment.

[0016] 2. The present application provides a control method for a radiation-resistant mechanical arm based on system postpositioning, which generates a time-ordered movement sequence according to task planning and target position, determines the optimal movement sequence using an optimization algorithm and a conflict detection algorithm, and finally controls multiple joint motors to move the mechanical arm body in the same or coordinated manner in the same time period through parallel control and dynamic coupling compensation; in this process, multiple joint motors can be controlled to move simultaneously in the same time, thereby improving the overall efficiency of the mechanical arm. Through testing, the algorithm can improve the efficiency of multiple motor single control mode by 80%, thereby further solving the problem of low overall efficiency of the mechanical arm caused by multiple joint motors working independently. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of an embodiment of the radiation-resistant mechanical arm based on system postpositioning of the present application; Figure 2 is a control principle diagram of an embodiment of the radiation-resistant mechanical arm based on system postpositioning of the present application.

[0018] The reference signs are as follows: 1-mechanical arm body; 2-driver; 3-multiplexing switch; 4-control switch; 5-joint motor; 6-processor. DETAILED DESCRIPTION

[0019] The technical solutions of the present application will be described in detail below with reference to the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] This invention provides a radiation-resistant robotic arm based on a rear-mounted system, which can be used in nuclear waste reprocessing hot chamber systems; such as... Figure 1 As shown, the system includes a robotic arm body 1, a driver 2, a multiplexer switch 3, four control switches 4, four articulated motors 5, and a processor. The driver 2, which is most sensitive to radiation, is located in the non-radiation area of ​​the robotic arm body 1. The multiplexer switch 3, the four control switches 4, and the four articulated motors 5 are located in the radiation area of ​​the robotic arm body 1. The processor 6 is used to generate a time-ordered list of articulated motor movements based on task planning and target position.

[0021] By placing the driver 2 at the rear of the system, the robot arm's radiation resistance is improved, ensuring that the robot arm can work normally for a long time in a radiation environment.

[0022] like Figure 2 As shown, the driver 2 incorporates a multi-motor cooperative control algorithm and a dynamic coupling observation algorithm. The processor 6 is used to generate a time-ordered list of joint motor motions based on the task planning and target position; and to generate corresponding motor drive signals based on the joint motor motion list. The joint motor motion list is a time-ordered motion sequence generated based on the task planning and target position. The multi-motor cooperative control algorithm performs parallel control calculations on the joint motor motion list, and the real-time dynamic coupling observation algorithm calculates the interaction force estimation and compensation between each joint motor 5, jointly generating the corresponding motor drive signals for the joint motor motion list.

[0023] In this embodiment, considering that when multiple joint motors 5 move simultaneously, they will generate dynamic interference (for example, the movement of one joint motor 5 will cause the load of another joint motor 5 to change), it is necessary to estimate and compensate for this coupling effect in real time. The dynamic coupling observation algorithm built into the driver 2 can ensure that each joint motor 5 can maintain accurate and stable movement when driven simultaneously.

[0024] In this embodiment, the 4-way multiplexer 3 has one input terminal, four signal control terminals, and four power output terminals. The one input terminal receives the motor drive signals corresponding to the joint motor motion list and generates four independent control commands. The four power output terminals control the power output. The one input terminal connects to the output terminal of the driver 2. The four power output terminals are respectively connected to the power input terminals of the four control switches 4. The four signal control terminals connect to the signal receiving terminals of the four control switches 4. By using the 4-way multiplexer 3 in this embodiment, only one power cable is needed to control all motor drives, simplifying the control circuit.

[0025] The output of each control switch 4 is connected to the input of one joint motor 5, and the joint motor 5 is located at the joint of the robotic arm body 1. The control switch 4 is used to control the joint motor 5 to move according to the control command, thereby driving the robotic arm body 1 to move.

[0026] This embodiment also provides a control method for a radiation-resistant robotic arm based on a system back-end, including the following steps: Step 1: Based on the kinematic model and task planning of the robotic arm, the processor 6 decomposes the overall motion task of the robotic arm into independent sub-tasks of each joint motor 5 according to the joint degrees of freedom, and determines the temporal relationship and cooperative constraints between each sub-task.

[0027] Step 2: Set the target position of the robotic arm, calculate the desired motion path of the robotic arm's end effector using a trajectory planning algorithm, and map the desired motion path of the robotic arm's end effector into a motion sequence of multiple joint motors 5 based on the inverse kinematics model. The trajectory planning algorithm is either a spline interpolation algorithm or a polynomial trajectory generation algorithm; in the motion sequence of the multiple joint motors 5, the motion sequence of each joint motor 5 includes the angle, angular velocity, and torque command sequence of each joint motor 5.

[0028] Step 3: Using the physical limits of the joint motor 5's motion, the temporal relationships between subtasks, and cooperative constraints as constraints, and aiming to minimize the total motion time or total energy consumption, an optimization algorithm is used to optimize the motion sequences of multiple joint motors 5. A conflict detection algorithm is then used to detect conflicts, determine the optimal motion sequence, and generate a list of joint motor motions sorted by time. Specifically: Step 3.1: Based on the temporal relationship between each subtask, rearrange the motion sequence of each group of joint motors 5 on a time scale. Using the physical limits of each joint motor's motion and the cooperative constraints between each subtask as constraints, and minimizing the total motion time or total energy consumption as the objective, use an optimization algorithm to perform optimization calculations on the rearranged motion sequence of each joint motor 5 to obtain multiple sets of better joint motor motion sequences. Then, sort the multiple sets of better joint motor motion sequences in ascending order of total motion time or total energy consumption. The optimization algorithm is either a dynamic programming algorithm or a genetic algorithm. Step 3.2: Using a conflict detection algorithm, mechanical interference or dynamic conflict detection is performed on the motion sequences of a group of excellent joint motors 5 according to the sorting. If mechanical interference or dynamic conflict occurs, mechanical interference or dynamic conflict detection is performed on the next group of motion sequences. Otherwise, the motion sequence of each joint motor in the current group of robotic arms is determined to be the optimal motion sequence. The conflict detection algorithm includes a motion interference detection method based on joint space or a motion interference detection method based on task space.

[0029] Step 3.3: Generate a list of joint motor movements sorted by time based on the optimal motion sequence.

[0030] Step 4: Input the joint motor motion list into the driver 2, perform parallel control calculations on the joint motor motion list through the multi-motor cooperative control algorithm, and calculate the interaction force estimation and compensation between each joint motor 5 through the real-time dynamic coupling observation algorithm to generate the corresponding motor drive signal. The 4-channel multiplexer 3 sends control commands to the control switch 4 according to the motor drive signal to control the joint motor 5 to move, thereby driving the robotic arm body 1 to move.

[0031] Based on the task planning and the time-ordered motion sequence generated by the target position, the optimal motion sequence is determined by optimization algorithm and conflict detection algorithm. Finally, multiple joint motors are controlled to drive the robotic arm body 1 to move in the same or coordinated manner within the same time period through parallel control and dynamic coupling compensation. In this process, multiple joint motors 5 can be controlled to move simultaneously, thereby improving the overall efficiency of the robotic arm.

[0032] Through testing, this algorithm can improve the efficiency of multiple motors in a single control mode by 80%, mainly because: (1) Reduce idle waiting time: Through parallel control, the waiting time of the joint motors 5 is significantly reduced, so that the robotic arm body 1 can participate in the movement almost "whole body" at the same time.

[0033] (2) Optimize motion trajectory: The optimal motion sequence is determined by combining the optimization algorithm with the conflict detection algorithm, which further solves the problem that the overall efficiency of the robotic arm is low due to the individual operation of multiple joint motors 5.

[0034] (3) Approaching the theoretical limit: This deep collaborative control enables the working efficiency of multiple joint motors 5 to approach the theoretical limit of their physical structure.

[0035] This invention discloses a control method for a radiation-resistant robotic arm based on a post-system architecture. It employs a multi-motor cooperative path planning algorithm, the core idea of ​​which is to enable multiple motors to work simultaneously and in a coordinated manner through parallel motion planning and dynamic coupling compensation. It likely combines distributed control architecture, adaptive control laws based on dynamic coupling observation, and high-speed real-time communication technologies, thereby significantly reducing the time required for the robotic arm to complete complex tasks and achieving a substantial improvement in overall efficiency.

[0036] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A post-system-based radiation-resistant mechanical arm, comprising a mechanical arm body (1) arranged in a radiation area, characterized in that: it further comprises a driver (2), an n-way multiplexing switch (3), n control switches (4), n joint motors (5) and a processor (6), n≥3; the processor (6) is used to generate a time-ordered joint motor motion list according to a task plan and a target position; the driver (2) is arranged in a non-radiation area and is internally provided with a multi-motor collaborative control algorithm and a dynamics coupling observation algorithm, and an input end of the driver (2) is connected to an output end of the processor (6) to generate corresponding motor driving signals according to the joint motor motion list; an output end of the driver (2) is connected to an input end of the n-way multiplexing switch (3) through a power cable, n power output ends of the n-way multiplexing switch (3) are respectively connected to power input ends of the n control switches (4), n signal control ends of the n-way multiplexing switch (3) are connected to signal receiving ends of the n control switches (4), and the n-way multiplexing switch (3) is used to receive the motor driving signals and send control instructions to corresponding control switches (4) of the motor driving signals; output ends of the n control switches (4) are respectively connected to input ends of the n joint motors (5), and the joint motors (5) are arranged at joints of the mechanical arm body (1); and the control switches (4) are used to control the joint motors (5) to move according to the control instructions. The method comprises the following steps: Step 1: The processor (6) decomposes the motion task of the mechanical arm into collaborative sub-tasks of the n joint motors (5) according to the task plan of the mechanical arm, and determines the time sequence relationship and collaborative constraints between the sub-tasks; Step 2: The expected motion path of the end of the mechanical arm is calculated according to the target position of the mechanical arm, and the expected motion path of the end of the mechanical arm is mapped to obtain a plurality of motion sequences of the joint motors (5); Step 3: Taking the physical limit of the joint motor (5) motion, the time sequence relationship and the collaborative constraints between the sub-tasks as constraint conditions, and taking the minimization of the total motion time or the total energy consumption as the target, an optimization algorithm is used to optimize the motion sequences of the plurality of joint motors (5), and a conflict detection algorithm is used for detection to determine the optimal motion sequence, and a time-ordered joint motor motion list is generated; Step 4: The joint motor motion list is input into the driver (2), and the plurality of joint motors (5) drive the mechanical arm body (1) to move in the same or coordinated manner within the same time period through parallel control and dynamic coupling compensation.

2. The control method of the post-system-based radiation tolerant robot according to claim 1, characterized in that, Step 1 is specifically: The processor 6 decomposes the overall motion task of the mechanical arm into collaborative sub-tasks of the joint motors (5) according to the kinematic model and the task plan of the mechanical arm, and determines the time sequence relationship and collaborative constraints between the sub-tasks. In step 2, the motion sequence of the joint motor (5) includes the angle, angular velocity and torque instruction sequence of the joint motor (5). Step 2 is specifically: ​ 3. The control method of claim 2, wherein, ​ ​ 4. The control method of the radiation tolerant robotic arm based on system post-processing according to claim 2, wherein: ​ 5. The control method of claim 4, wherein, ​ Setting a target position of the robot arm, calculating a desired motion path of the robot arm end through a trajectory planning algorithm, and mapping the desired motion path of the robot arm end into a plurality of motion sequences of the joint motors (5) according to an inverse kinematics model.

6. The control method of the radiation tolerant robotic arm based on system post-processing according to claim 5, wherein: In step 2, the trajectory planning algorithm is a spline interpolation algorithm or a polynomial trajectory generation algorithm.

7. The control method of the radiation tolerant robotic arm based on system post- processing according to claim 2, wherein, Step 3 is specifically: Step 3.1, rearranging the motion sequences of each group of joint motors (5) in the time scale according to the time sequence relationship between each subtask, taking the physical limit of each joint motor movement and the coordination constraint between each subtask as the constraint condition, taking the minimum total movement time or total energy consumption as the target, and using an optimization algorithm to optimize the motion sequence of each joint motor (5) after rearrangement, obtaining a plurality of optimal joint motor motion sequences, and sorting the plurality of optimal joint motor motion sequences according to the total movement time or total energy consumption from small to large; Step 3.2, using a conflict detection algorithm to detect mechanical interference or dynamics conflict of a group of excellent joint motor (5) motion sequences according to the sorting, if mechanical interference or dynamics conflict occurs, the mechanical interference or dynamics conflict detection of the next group of motion sequences is carried out, otherwise, the motion sequence of each joint motor in the current group of robot arms is determined as the optimal motion sequence; Step 3.3, generating a joint motor motion list sorted by time according to the optimal motion sequence.

8. The control method of the radiation tolerant robotic arm based on system post-processing according to claim 7, wherein: In step 3.1, the optimization algorithm is a dynamic programming algorithm or a genetic algorithm; In step 3.2, the conflict detection algorithm includes a joint space-based motion interference detection method or a task space-based motion interference detection method.

9. The control method of the radiation tolerant robotic arm based on system post- processing according to claim 2, wherein, Step 4 is specifically: Input the joint motor motion list into the driver (2), perform parallel control calculation on the joint motor motion list through a multi-motor cooperative control algorithm, and calculate the interaction force estimation and compensation between each joint motor (5) through a real-time dynamics coupling observation algorithm to generate corresponding motor driving signals, the n-way multiplexing switch (3) sends control instructions to the n control switches (4) according to the motor driving signals, controls the corresponding joint motor (5) to act, thereby driving the robot arm body (1) to move in the same or coordinated manner within the same time period.

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