Master-slave isomorphic teleoperation force feedback control method based on double force sensors

Abstract

The invention relates to the technical field of robot force feedback teleoperation, and discloses a master-slave isomorphic teleoperation force feedback control method based on double force sensors. The method comprises the steps that main arm operation equipment and slave arm execution equipment are arranged, a first force sensor is arranged at an operation handle of the main arm operation equipment, and a second force sensor is arranged at the execution tail end of the slave arm execution equipment; detecting a force signal applied to the operating handle by an operator through the first force sensor, and meanwhile, detecting an external force signal borne by the slave arm execution equipment in the task execution process through the second force sensor; respectively preprocessing the detected force signal and the detected external force signal; calculating a force signal fed back to the operating handle through a force feedback control algorithm according to the processed slave arm force signal; and calculating a force tracking error between the processed master arm force signal and the processed slave arm force signal, and according to the force tracking error, calculating a motion control quantity of the operating handle through a force tracking control algorithm.

Description

Technical Field

[0001] The present invention relates to the technical field of robot force feedback teleoperation, and in particular to a master-slave isomorphic teleoperation force feedback control method based on dual force sensors. Background Art

[0002] With the rapid development of modern science and technology, the demand for fine operations in complex environments in various fields is increasing, and the master-slave remote operation technology of robotic arms has emerged. This technology aims to achieve precise force control and position control of robotic arms through remote control, bringing new opportunities and breakthroughs to the development of many industries.

[0003] In actual application scenarios, operators often need to be far away from the work site, such as complex production environments in industrial manufacturing, sterile operating spaces in medical surgery, external operations in space exploration, and dangerous areas in disaster relief. The master-slave teleoperation technology of the robotic arm can meet these needs. It allows the operator to control the slave robotic arm through the master operator while being far away from the above-mentioned work sites, and obtain force feedback information, thereby enhancing the accuracy and safety of the operation.

[0004] As a key component of this teleoperation technology, force feedback technology enables the operator to truly feel the force acting on the robot arm in a remote environment by accurately measuring and effectively transmitting the interaction force between the operator and the environment. This is crucial for the operator to accurately grasp the operating force and avoid over-operation or under-operation.

[0005] At the same time, between the master arm and the slave arm, the spatial mapping between the master and slave devices is realized through position mapping technology to ensure the accuracy and real-time performance of the operation. This spatial mapping can ensure that the movements of the master operator correspond precisely to the movements of the slave robotic arm, allowing the operator to perform precise operations as if they were actually there during remote control.

[0006] The master-slave teleoperation technology of robotic arms has been widely used in many fields due to its unique advantages. In the field of industrial manufacturing, teleoperated robotic arms are widely used to perform complex assembly, welding and handling tasks. Since some links in the industrial manufacturing process involve high-precision requirements and working environments that may be harmful to the human body, teleoperated robotic arms can provide precise force feedback to help operators complete delicate operations in a safe environment, which not only improves production efficiency, but also ensures the health and safety of operators.

[0007] In the medical field, especially in minimally invasive surgery, teleoperation technology plays an extremely important role. Minimally invasive surgery requires surgeons to complete the operation under the premise of minimizing the trauma to the patient's body. The internal tissue structure of the human body is complex, and the hardness and resistance of the tissue vary. The teleoperated robotic arm combined with force feedback technology enables surgeons to accurately sense the changes in the hardness and resistance of the tissue in the body, so as to perform more precise surgical operations, greatly improving the success rate of the operation and the patient's recovery effect.

[0008] During the space exploration mission, the maintenance and assembly of the International Space Station faces many challenges, such as the special conditions of high vacuum and microgravity in the space environment, as well as the high risk of astronauts' extravehicular operations. The remote-controlled robotic arm has shown great advantages in such missions, providing accurate force feedback to ground operators to ensure the smooth completion of the mission, effectively reducing the frequency and risk of astronauts' extravehicular operations, and ensuring the steady progress of space exploration missions.

[0009] In disaster rescue scenarios, such as dealing with hazardous material leaks and repairing damaged equipment, the on-site environment is often very dangerous, posing a serious threat to the lives of rescuers. Teleoperation technology allows operators to control the robotic arm to perform delicate operations away from danger, which not only ensures the implementation of rescue missions, but also protects the personal safety of rescuers to the greatest extent.

[0010] However, although the robot arm master-slave teleoperation technology has achieved remarkable results in many of the above-mentioned fields, there are still some areas that need to be further optimized and improved. Specifically, the robot arm master-slave teleoperation technology currently has the following major defects and problems:

[0011] 1. Due to the size limitation of the end of the currently commonly used main arm, it is difficult to install a force sensor to obtain force feedback information, resulting in a lack of force feedback during remote operation, affecting the accuracy and safety of the operation.

[0012] 2. After the slave arm has a rigid collision with the outside world, the control fusion of position feedback and force feedback will cause the teleoperation system to oscillate, resulting in the inability to achieve stable control.

[0013] 3. It is impossible to simultaneously realize the fusion of full-space control and local-space fine control of the slave arm. Summary of the invention

[0014] The invention provides a master-slave isomorphic teleoperation force feedback control method based on dual force sensors, which can solve the technical problems in the prior art.

[0015] The present invention provides a master-slave isomorphic teleoperation force feedback control method based on dual force sensors, wherein the method comprises:

[0016] A master arm operating device and a slave arm executing device are provided, wherein the master arm operating device and the slave arm executing device are of isomorphic structure, and a first force sensor is provided at the operating handle of the master arm operating device, and a second force sensor is provided at the executing end of the slave arm executing device;

[0017] The first force sensor is used to detect the force signal Fm(t) applied by the operator to the operating handle, where t represents time, and the second force sensor is used to detect the external force signal Fs(t) received by the slave arm execution device during the execution of the task;

[0018] Preprocessing the detected force signal Fm(t) and the external force signal Fs(t) respectively to obtain a processed master arm force signal Fm'(t) and a processed slave arm force signal Fs'(t);

[0019] According to the processed slave arm force signal Fs'(t), the force signal Ffb(t) fed back to the operating handle is calculated by the force feedback control algorithm;

[0020] The force tracking error e(t) between the processed master arm force signal Fm'(t) and the processed slave arm force signal Fs'(t) is calculated, and the motion control amount of the operating handle is calculated through the force tracking control algorithm according to the force tracking error e(t).

[0021] Preferably, the force signal Ffb(t) fed back to the operating handle is calculated by the following formula:

[0022] Ffb(t)=k×Fs'(t),

[0023] Wherein, k is the feedback force proportional coefficient.

[0024] Preferably, the force tracking error e(t) is calculated by the following formula:

[0025] e(t)=Fm'(t)-Fs'(t).

[0026] Preferably, the force tracking control algorithm is a proportional integral derivative PID control algorithm.

[0027] Preferably, the motion control amount of the operating handle is calculated by the following formula:

[0028] u(t)=Kp×e(t)+Ki×∫e(t)dt+Kd×de(t) / dt,

[0029] Among them, u(t) is the control quantity, which is used to adjust the movement of the main arm operating handle, Kp is the control proportional coefficient, Ki is the integral coefficient, and Kd is the differential coefficient.

[0030] Preferably, the method further comprises:

[0031] Real-time monitoring of the force signal Fm(t), the external force signal Fs(t), the force signal Ffb(t) fed back to the operating handle, and the force tracking error e(t);

[0032] According to the monitoring results, the feedback force proportional coefficient k, control proportional coefficient Kp, integral coefficient Ki and differential coefficient Kd are adjusted.

[0033] Through the above technical scheme, force sensors can be installed at the ends of the remote-controlled main arm and the slave arm. The force sensor at the end of the main arm is used to sense the force applied by the operator at the end of the main arm, and serves as the data basis for adjusting the force feedback at the end of the main arm; the force sensor at the end of the slave arm is used to sense the force between the end of the slave arm and the environment, and serves as the data basis for the compliant control of the end of the slave arm, thereby realizing the posture tracking of the slave arm according to the posture of the end of the main arm and the force feedback of the master arm according to the force condition at the end of the slave arm. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 A flow chart of a master-slave isomorphic teleoperation force feedback control method based on dual force sensors according to an embodiment of the present invention is shown;

[0036] Figure 2 A block diagram of a master-slave isomorphic teleoperation force feedback control system based on dual force sensors according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0039] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0040] Figure 1 A flow chart of a master-slave isomorphic teleoperation force feedback control method based on dual force sensors according to an embodiment of the present invention is shown.

[0041] like Figure 1 As shown, an embodiment of the present invention provides a master-slave isomorphic teleoperation force feedback control method based on dual force sensors, wherein the method comprises:

[0042] A master arm operating device and a slave arm executing device are provided, wherein the master arm operating device and the slave arm executing device are of isomorphic structure, and a first force sensor is provided at the operating handle of the master arm operating device, and a second force sensor is provided at the executing end of the slave arm executing device;

[0043] The first force sensor and the second force sensor may be six-dimensional force sensors.

[0044] The first force sensor is used to detect the force signal Fm(t) applied by the operator to the operating handle, where t represents time, and the second force sensor is used to detect the external force signal Fs(t) received by the slave arm execution device during the execution of the task;

[0045] The first force sensor and the second force sensor can be compensated for gravity and inertial force respectively, so as to ensure that the six-dimensional force sensor can accurately measure the direct force between the ends of the main arm and the slave arm and the outside world.

[0046] Preprocessing the detected force signal Fm(t) and the external force signal Fs(t) respectively to obtain a processed master arm force signal Fm'(t) and a processed slave arm force signal Fs'(t);

[0047] Among them, the preprocessing may include filtering processing and amplification processing. The filtering processing is used to remove noise interference, and the amplification processing is used to enhance the signal strength, so that the processed force signal can more accurately reflect the actual force situation.

[0048] According to the processed slave arm force signal Fs'(t), the force signal Ffb(t) fed back to the operating handle is calculated by the force feedback control algorithm;

[0049] The force tracking error e(t) between the processed master arm force signal Fm'(t) and the processed slave arm force signal Fs'(t) is calculated, and the motion control amount of the operating handle is calculated through the force tracking control algorithm according to the force tracking error e(t).

[0050] Through the above technical scheme, force sensors can be installed at the ends of the remote-controlled main arm and the slave arm. The force sensor at the end of the main arm is used to sense the force applied by the operator at the end of the main arm, and serves as the data basis for adjusting the force feedback at the end of the main arm; the force sensor at the end of the slave arm is used to sense the force between the end of the slave arm and the environment, and serves as the data basis for the compliant control of the end of the slave arm, thereby realizing the posture tracking of the slave arm according to the posture of the end of the main arm and the force feedback of the master arm according to the force condition at the end of the slave arm.

[0051] In the present invention, when the position of the slave arm is not subject to external force or is subject to a small external force, it can be completely controlled by the position of the end of the slave arm. When it is subject to a large external force, the position of the slave arm is not completely controlled by the position of the end of the master arm. Its actual control position is to make a certain position compensation based on the mapped position of the end of the master arm. The position compensation value can be determined by the admittance control method. This control method can effectively avoid the oscillation that may occur when the slave arm collides hard with the environment.

[0052] Furthermore, since the control space of the master arm is relatively small compared to the slave arm, direct position mapping control will result in limited movement space of the slave arm. In the control method described in the present invention, when the master arm moves to the edge of the restricted space, the slave arm will continue to move in the direction of the center point of the master arm's movement space and the current edge point, thereby achieving full space control. In addition, the spatial mapping ratio of the master arm and the slave arm can be adjusted by the end lever, and reducing the mapping ratio will be beneficial to the fine control of the local space. That is, the master arm can achieve full space control and local space fine control of the slave arm.

[0053] According to one embodiment of the present invention, the force signal (force feedback signal) Ffb(t) fed back to the operating handle is calculated by the following formula:

[0054] Ffb(t)=k×Fs'(t),

[0055] Wherein, k is the feedback force proportional coefficient.

[0056] Among them, by adjusting the value of the feedback force proportional coefficient k, the size of the feedback force can be controlled to adapt to the perception needs of different operators and the operational requirements of different tasks.

[0057] That is, the external force applied to the slave arm can be fed back to the main arm operating handle in an appropriate proportion and manner through the force feedback control algorithm, so that the operator can intuitively feel the external force applied to the slave arm execution device.

[0058] According to one embodiment of the present invention, the force tracking error e(t) is calculated by the following formula:

[0059] e(t)=Fm'(t)-Fs'(t).

[0060] According to one embodiment of the present invention, the force tracking control algorithm is a proportional integral derivative (PID) control algorithm.

[0061] According to one embodiment of the present invention, the motion control amount of the operating handle is calculated by the following formula:

[0062] u(t)=Kp×e(t)+Ki×∫e(t)dt+Kd×de(t) / dt,

[0063] Among them, u(t) is the control quantity, which is used to adjust the movement of the main arm operating handle, Kp is the control proportional coefficient, Ki is the integral coefficient, and Kd is the differential coefficient.

[0064] Among them, by adjusting the values ​​of Kp, Ki and Kd, the force tracking error can be effectively controlled and the accuracy and stability of force tracking can be improved.

[0065] That is, the movement of the master arm operating handle can be adjusted through the force tracking control algorithm, so that the master arm operating force can better track the external force applied to the slave arm, thereby achieving effective force matching between the master and slave arms.

[0066] According to one embodiment of the present invention, the method further includes:

[0067] Real-time monitoring of the force signal Fm(t), the external force signal Fs(t), the force signal Ffb(t) fed back to the operating handle, and the force tracking error e(t);

[0068] According to the monitoring results, the feedback force proportional coefficient k, control proportional coefficient Kp, integral coefficient Ki and differential coefficient Kd are adjusted.

[0069] That is, during the teleoperation process, relevant parameters such as the force signal Fm(t), Fs(t), the force feedback signal Ffb(t), and the force tracking error e(t) can be monitored in real time. According to the monitoring results, the feedback force proportional coefficient k, the parameters Kp, Ki, and Kd in the PID control algorithm can be adjusted in a timely manner to ensure that the effect of force feedback and force tracking control is always in the best state and adapt to the changes in different mission stages and operating environments.

[0070] A master-slave isomorphic teleoperation force feedback control system that implements the master-slave isomorphic teleoperation force feedback control method based on dual force sensors of the present invention is as follows: Figure 2 As shown. The master-slave isomorphic teleoperation force feedback control system controls the master arm operating device and the slave arm execution device through the host computer controller. The master arm operating device includes an operating handle, a desktop-level six-degree-of-freedom robotic arm, a six-dimensional force sensor, and a parameter adjustment lever. The slave arm execution device includes an AR series six-degree-of-freedom robotic arm, a six-dimensional force sensor, a six-dimensional force sensor feedback system, and an end effector.

[0071] It can be seen from the above embodiments that the master-slave isomorphic teleoperation force feedback control method based on dual force sensors described in the present invention has at least the following advantages: 1. The master arm realizes direct force perception of the force applied by the operator and direct force feedback of the force received by the slave arm, which solves the problem that the teleoperation master arm cannot perceive the actual force applied by the operator's hand at the end; 2. The slave arm avoids hard collision with the environment through admittance control, that is, the slave arm can avoid oscillation of position control after a rigid collision with the outside world; 3. The full-space control and local-space fine control of the slave arm by the master arm are simultaneously realized without changing the stiffness setting of the slave arm.

[0072] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0073] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0074] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0075] 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 modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A master-slave isomorphic teleoperation force feedback control method based on dual force sensors, characterized in that: The method includes: A master arm operating device and a slave arm executing device are provided, wherein the master arm operating device and the slave arm executing device are of isomorphic structure, and a first force sensor is provided at the operating handle of the master arm operating device, and a second force sensor is provided at the executing end of the slave arm executing device; The first force sensor is used to detect the force signal Fm(t) applied by the operator to the operating handle, where t represents time, and the second force sensor is used to detect the external force signal Fs(t) received by the slave arm execution device during the execution of the task; Preprocessing the detected force signal Fm(t) and the external force signal Fs(t) respectively to obtain a processed master arm force signal Fm'(t) and a processed slave arm force signal Fs'(t); According to the processed slave arm force signal Fs'(t), the force signal Ffb(t) fed back to the operating handle is calculated by the force feedback control algorithm; The force tracking error e(t) between the processed master arm force signal Fm'(t) and the processed slave arm force signal Fs'(t) is calculated, and the motion control amount of the operating handle is calculated through the force tracking control algorithm according to the force tracking error e(t).

2. The method according to claim 1, characterized in that The force signal Ffb(t) fed back to the operating handle is calculated by the following formula: Ffb(t)=k×Fs'(t), Wherein, k is the feedback force proportional coefficient.

3. The method according to claim 2, characterized in that The force tracking error e(t) is calculated by the following formula: e(t)=Fm'(t)-Fs'(t).

4. The method according to claim 3, characterized in that The force tracking control algorithm is a proportional-integral-derivative PID control algorithm.

5. The method according to claim 4, characterized in that The motion control amount of the operating handle is calculated by the following formula: u(t)=Kp×e(t)+Ki×∫e(t)dt+Kd×de(t) / dt, Among them, u(t) is the control quantity, which is used to adjust the movement of the main arm operating handle, Kp is the control proportional coefficient, Ki is the integral coefficient, and Kd is the differential coefficient.

6. The method according to claim 5, characterized in that The method further includes: Real-time monitoring of the force signal Fm(t), the external force signal Fs(t), the force signal Ffb(t) fed back to the operating handle, and the force tracking error e(t); According to the monitoring results, the feedback force proportional coefficient k, control proportional coefficient Kp, integral coefficient Ki and differential coefficient Kd are adjusted.

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