A tactile force feedback system and a force feedback adjustment method

Abstract

The present application relates to the technical field of rehabilitation training, and discloses a tactile force feedback system and a force feedback adjustment method, the system comprising: an external terminal with a virtual system and a robot system; a magnetic circuit is formed between the handle and the magnetic fixed platform to provide output force; the electrical system is used to collect the motion position information of the handle in real time; the external terminal is used to determine the control information based on the position information and the applied force information and send it to the electrical system, so that the electrical system can adjust the output magnetic force of the handle. The method is applied to the external terminal in the above-mentioned system, and comprises: determining the user's motion intention when performing a training task based on the applied force information applied by the user on the handle; generating control information based on the motion intention and the position information of the handle on the magnetic fixed platform; wherein the control information is sent to the handle via the electrical system to indicate the output magnetic force of the handle, so that the output force matches the motion intention. The present application can achieve safe and effective rehabilitation training.

Description

Technical Field

[0001] The present application relates to the field of rehabilitation training technology, and in particular to a tactile force feedback system and a force feedback adjustment method. Background Art

[0002] Currently, the number of patients with reduced ability to care for themselves due to stroke continues to rise, yet the number of professional rehabilitation personnel has not increased accordingly. Against this backdrop, rehabilitation equipment has become the primary means of assisting patients in rehabilitation training. It is worth noting that among the stroke patient population, those with upper limb motor dysfunction account for a large proportion. Existing upper limb rehabilitation training equipment is mainly divided into two categories: one is active equipment driven by a motor, and the other is passive equipment driven by a brake. In comparison, passive rehabilitation training equipment uses lower-cost brakes and the system has passive characteristics (i.e., it does not actively provide power to the user). This ensures safety while having the potential to simulate daily life tasks, and therefore is widely used.

[0003] However, existing passive rehabilitation training devices still have the following technical limitations: First, although such devices can provide a certain amount of force feedback, their resistance output value is relatively single and cannot be continuously and dynamically adjusted according to the patient's real-time movement status and rehabilitation needs, making them difficult to adapt to the training requirements of different rehabilitation stages. Second, some rehabilitation devices adjust the feedback force by replacing counterweights of different weights. This method not only cannot achieve real-time control of feedback force during training, but also cannot effectively simulate common task scenarios in daily life. These technical shortcomings have, to a certain extent, restricted the effectiveness of rehabilitation training and the patient's recovery process. Summary of the Invention

[0004] In view of this, embodiments of the present application provide a tactile force feedback system and a force feedback adjustment method.

[0005] In a first aspect, an embodiment of the present application provides a tactile force feedback system, comprising: an external terminal with a virtual system and a robot system; the robot system comprises a handle, a magnetic fixed platform, and an electrical system;

[0006] The handle is arranged on the magnetic fixed platform, and a magnetic circuit is formed between the handle and the magnetic fixed platform for providing output force feedback to the user;

[0007] The electrical system is connected to the handle and is used to collect position information of the handle on the magnetic fixed platform in real time;

[0008] The external terminal is connected to the electrical system, and is used to determine control information based on the position information and the user-applied force information, and send the control information to the electrical system so that the electrical system adjusts the output magnetic force of the handle according to the control information, thereby matching the output force with the movement intention.

[0009] In an optional embodiment, the handle includes a force sensor, an electromagnet and an armrest;

[0010] The force sensor and the electromagnet are arranged below the armrest portion;

[0011] The force sensor is used to obtain the applied force information applied by the user to the armrest portion; wherein the applied force information includes the applied force applied by the user to the armrest portion of the handle and the direction of the applied force;

[0012] The electromagnet is used to form a closed magnetic circuit with the armature part of the magnetic fixed platform to generate the output force.

[0013] In an optional embodiment, the electrical system includes: a controller, an adjustable power supply, and a positioning sensor;

[0014] The positioning sensor is used to collect position information of the handle on the magnetic fixed platform;

[0015] The controller is configured to receive the position information sent by the positioning sensor and send the position information to the external terminal; wherein the position information is used to instruct a virtual object in a virtual system built into the external terminal to maintain synchronization with the position of the handle;

[0016] The controller is further configured to adjust the adjustable power supply according to the received control information so as to adjust the magnetic force of the electromagnet.

[0017] In a second aspect, an embodiment of the present application provides a force feedback adjustment method, which is applied to an external terminal in a tactile force feedback system as described in any of the preceding embodiments, wherein a virtual system of the external terminal includes a preset training task, and the force feedback adjustment method includes:

[0018] determining, based on information about the force applied by the user on the handle, the user's movement intention when performing the training task;

[0019] Control information is generated based on the movement intention and the position information of the handle on the magnetic fixed platform; wherein, the control information is sent to the handle through the electrical system to indicate the output magnetic force of the handle so that the output force matches the movement intention.

[0020] In an optional embodiment, the applied force information includes the applied force applied by the user to the armrest portion of the handle and the direction of the applied force;

[0021] The force information applied by the user on the handle is used to determine the movement intention of the user when performing the training task, including:

[0022] The user's movement intention when performing the training task is determined based on the force applied by the user to the armrest of the handle and the direction of the force applied; wherein the movement intention includes moving forward, moving backward, turning and stopping.

[0023] In an optional embodiment, the generating of control information based on the movement intention and the position information of the handle on the magnetic fixed platform includes:

[0024] Mapping the position information of the handle on the magnetic fixed platform obtained in real time to the target position of the virtual object in the virtual system;

[0025] The control information is determined based on the motion intention and the target position of the virtual object in the virtual system; wherein the control information includes adjustment information for the output current of the adjustable power supply in the electrical system.

[0026] In an optional embodiment, the output force is determined based on the friction factor between the handle and the magnetic fixed platform, the vertical force applied by the user to the magnetic fixed platform through the handle, the gravity of the handle, and the output magnetic force of the electromagnet in the handle.

[0027] In an optional embodiment, after generating the control information based on the movement intention and the position information of the handle on the magnetic fixed platform, the method further includes:

[0028] determining an adjustment amount for a current output current of the adjustable power supply according to a difference between the output force and a desired output force;

[0029] updating the control information according to the adjustment amount to generate new control information, and sending the new control information to the electrical system so that the electrical system adjusts the output current of the adjustable power supply according to the new control information, thereby adjusting the output magnetic force of the handle;

[0030] A new output force is determined based on the adjusted output magnetic force, the vertical force applied by the handle on the magnetic fixed platform, and the gravity of the handle until the difference between the output force and the expected output force is within a preset difference range.

[0031] In an optional embodiment, determining the adjustment amount for the current output current of the adjustable power supply based on the difference between the output force and the expected output force includes: determining the adjustment amount for the current output current of the adjustable power supply based on the difference between the output force and the expected output force in combination with a proportional-integral-differential control algorithm;

[0032] The calculation formula of the adjustment amount is:

[0033]

[0034] Where, is the proportional gain; is the integral gain; is the differential gain; u is the adjustment amount; e is the difference between the output force and the expected output force.

[0035] In a third aspect, an embodiment of the present application provides a force feedback adjustment method, which is applied to an external terminal and a robot system in a tactile force feedback system as described in any of the preceding embodiments, wherein the virtual system of the external terminal includes a preset training task, and the force feedback adjustment method includes:

[0036] The robot system sends information about the force applied by the user on the handle and information about the position of the handle on the magnetic fixed platform to the external terminal;

[0037] The external terminal determines the user's movement intention when performing the training task based on the applied force information, and generates control information based on the movement intention and the position information of the handle on the magnetic fixed platform;

[0038] The control information is sent to the handle via the electrical system in the robot system, and is used to indicate the output magnetic force of the handle so that the output force matches the movement intention.

[0039] The embodiments of the present application have the following beneficial effects:

[0040] The tactile force feedback system of the present application includes an external terminal with a virtual system and a robotic system; the robotic system includes a handle, a magnetic fixed platform, and an electrical system. The electrical system can collect the position information of the handle on the magnetic fixed platform and then send the position information to the external terminal. Based on the received position information and the force applied by the user to the handle, the external terminal can determine control information for adjusting the output magnetic force of the handle and send this control information to the electrical system. The electrical system adjusts the output magnetic force of the handle based on the control information. The present application combines task-oriented training in a virtual environment with real-time adjustment of output force feedback, making force feedback training more tailored to the patient's actual needs. When performing output force feedback, the present application uses the magnetic circuit formed between the handle and the magnetic fixed platform for adjustment, avoiding the impact risk of active rehabilitation robot motor drive methods and ensuring the safety of the training process. In addition, the system of the present application has a simple structure, low cost, and is easy to deploy, making it particularly suitable for home rehabilitation environments. It does not rely on large equipment and is more convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 A structural diagram of a tactile force feedback system according to an embodiment of the present application is shown;

[0043] Figure 2a A schematic diagram of the handle structure of this embodiment of the present application is shown;

[0044] Figure 2b A schematic diagram of the electrical system structure of this embodiment of the present application is shown;

[0045] Figure 3 A first flow chart of the force feedback adjustment method according to an embodiment of the present application is shown;

[0046] Figure 4 A second flow chart of the force feedback adjustment method according to an embodiment of the present application is shown;

[0047] Figure 5 A schematic diagram of a friction model according to an embodiment of the present application is shown;

[0048] Figure 6 A schematic diagram of the output force adjustment process according to an embodiment of the present application is shown;

[0049] Figure 7 A third flow chart of the force feedback adjustment method according to an embodiment of the present application is shown.

[0050] Explanation of the main component symbols: 100-external terminal; 200-robot system; 210-handle; 220-magnetic fixed platform; 230-electrical system; 211-force sensor; 212-electromagnet; 213-armrest; 231-controller; 232-adjustable power supply; 233-DC power supply; 234-positioning sensor. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described clearly and completely 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, rather than all the embodiments.

[0052] The components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but rather merely represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0053] Hereinafter, the terms "including", "having" and their cognates used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the aforementioned items, and should not be understood as excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the aforementioned items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the aforementioned items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and should not be understood as indicating or implying relative importance.

[0054] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as in the context of the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present application.

[0055] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0056] Stroke not only impairs patients' cognitive abilities but also reduces their ability to function independently, placing a heavy burden on their families and society. As the number of stroke patients continues to grow globally, the number of people engaged in rehabilitation therapy has not increased accordingly. Traditional rehabilitation, with its one-on-one treatment model between therapist and patient, has exacerbated the shortage of stroke treatment resources.

[0057] In rehabilitation training, guiding patients to engage in active movement and feel external forces acting on their trunk is an effective way to promote cognitive recovery and relearn life skills. In recent years, the application of robotics in stroke rehabilitation has been growing. For upper limb rehabilitation of stroke patients, robots can provide precise and controllable force-tactile rehabilitation training. By combining training tasks with feedback such as images and sounds, patients can better acquire life skills and ultimately return to society. However, due to their high cost, rehabilitation robots are only commonly found in medium- and large-scale medical institutions. Rehabilitation robots also face a similar shortage of rehabilitation practitioners, resulting in a lack of widespread promotion of the force feedback and task-based training treatment models they incorporate. Therefore, developing a low-cost, easy-to-use rehabilitation robot suitable for community or home settings is crucial for the rehabilitation training of stroke patients.

[0058] Based on the driving mode, rehabilitation robots can be divided into active types driven by motors and passive types driven by brakes. The brakes used in passive robots are less expensive, and their systems are passive and do not provide power to the user. They have both safety and the potential to simulate daily life tasks, and are therefore expected to be used for home rehabilitation. However, existing rehabilitation equipment still has limitations in terms of task-oriented passive force feedback regulation. Especially in home rehabilitation scenarios, these devices are insufficient in their ability to dynamically adjust passive force output according to task requirements and have limited ability to simulate daily life tasks, which is not conducive to the effectiveness of patient force feedback training. Therefore, the present invention proposes a tactile force feedback system and a force feedback adjustment method, which enable users (patients) to adjust passive force feedback in real time during rehabilitation training, and combine task-oriented training in a virtual system (such as mopping the floor, pushing boxes, etc.) to more realistically simulate common tasks in daily life, thereby helping patients to more effectively recover their motor functions.

[0059] The tactile force feedback system of the present application is first described below with reference to some specific embodiments.

[0060] like Figure 1 As shown, the tactile force feedback system includes: an external terminal 100 with a virtual system and a robot system 200.

[0061] Exemplarily, this virtual system, developed based on a real-time 3D interactive content creation and operation platform (e.g., Unity), simulates a virtual environment in which two hands can move objects. This virtual environment includes virtual objects and scenes, including but not limited to surfaces with varying friction coefficients (e.g., grass, asphalt, brick, and dirt roads) and virtual walls (used to simulate pushing an object against a wall). Virtual objects can be spherical or square. The virtual system can be installed on an external terminal 100, such as a computer, host computer, or iPad.

[0062] To ensure task-oriented training and make it more planned, the virtual system can be pre-set with pre-set training tasks. For example, a task involving pushing an object can be designed in the virtual system. The user needs to control the virtual object (such as a box or ball) in the virtual environment by moving the handle 210 to push it to a specified location. As the patient pushes the virtual object toward its final position, different resistance zones are set along the path. The external terminal 100 calculates the object's position and the force applied by the user, generates a corresponding control signal, and transmits it to the electrical system. The electrical system adjusts the output current of the adjustable power supply 232 to adjust the magnetic force output of the electromagnet 212, thereby adjusting the real-time resistance when pushing the object.

[0063] The virtual system can be used for, but is not limited to, friction model training, virtual wall model training, and virtual rigid body model training. For the friction model, in the virtual system, the model is intended to simulate the change in friction when a virtual object slides between surfaces of different materials or the same material, such as moving an object from a grass area to a stone slab area. For the virtual wall model, the model is intended to simulate the force feedback performance of an object when it contacts a rigid surface. In this embodiment, motion intention recognition is added to the model to determine whether the virtual object is trying to leave the wall or further penetrate the wall, thereby dynamically switching between high and low resistance. When the controlled virtual object collides with the virtual wall model, the system makes a judgment based on the motion intention of the controlled object. When the force applied to the controlled object is toward the inside of the wall, the system will apply a larger feedback force. (e.g. a force greater than 15N) to prevent the controlled object from further penetrating the wall; otherwise, the system applies a smaller force (For example, the current ground corresponds to friction) to control the object to more easily break away from the wall. For the virtual rigid body model, this model is suitable for simulating tasks in daily life where objects come into contact and change their motion state.

[0064] like Figure 1 、 Figure 2a 、 Figure 2b As shown, the robotic system 200 includes a handle 210 , a magnetic fixed platform 220 and an electrical system 230 .

[0065] The handle 210 is disposed on the magnetic fixed platform 220 , and a magnetic circuit is formed between the handle 210 and the magnetic fixed platform 220 for providing output force feedback to the user.

[0066] Exemplarily, the handle 210 includes a force sensor 211, an electromagnet 212, and an armrest 213. When the handle 210 is placed on the magnetic fixed platform 220, the force sensor 211 and the electromagnet 212 are arranged below the armrest 213. The force sensor 211 and the electromagnet 212 are connected by a connecting plate. The armrest 213 is the position that directly contacts the user's hand when the user performs rehabilitation training through the tactile force feedback system. The force sensor 211 is used to obtain the force applied by the user to the armrest 213 and the direction of the applied force. The electromagnet 212 is used to form a closed magnetic circuit with the armature part of the magnetic fixed platform 220 to generate an output force.

[0067] The magnetic stationary platform 220 provides a workspace and magnetic force output for the robotic system 200. It consists of a base plate (which can be made of 20# steel with a chrome plating) and an acrylic cover. The base plate serves as the armature for the electromagnet 212 and, together with the electromagnet 212, provides the system's output force. The cover is used to secure the positioning sensor 234.

[0068] The electrical system 230 is connected to the handle 210. A spring-loaded wire flexibly connects the handle 210 and the electrical system 230 to transmit signals and power. This allows for real-time acquisition of the handle 210's position on the magnetic fixed platform 220. The handle 210 corresponds to a virtual object in the virtual system. The electrical system 230 collects this position information and feeds it back to the virtual system. The virtual object in the virtual environment then moves according to the movement of the handle 210.

[0069] Specifically, the electrical system 230 includes a controller 231, an adjustable power supply 232, and a positioning sensor 234 (not shown). The positioning sensor 234 is used to collect position information of the handle 210 on the magnetic fixed platform 220 and transmit this position information to the external terminal 100 via the controller 231, thereby synchronizing the virtual objects in the virtual system built into the external terminal 100 with the position of the handle 210. The controller 231 is also used to adjust the adjustable power supply 232 based on received control information to adjust the magnetic force of the electromagnet 212. The control information includes information for adjusting the output current of the adjustable power supply 232 in the electrical system 230. The electrical system 230 also includes a DC power supply 233, which is used to power the controller 231 and other components.

[0070] The external terminal 100 is connected to the electrical system 230, and is used to determine control information based on position information and user-applied force information, and send the control information to the electrical system 230 so that the electrical system 230 adjusts the output magnetic force of the handle 210 according to the control information, thereby matching the output force with the movement intention.

[0071] Exemplarily, the applied force information includes the applied force and the direction of the applied force applied by the user to the armrest portion 213 of the handle 210. Based on the applied force and the direction of the applied force applied by the user to the armrest portion 213 of the handle 210, it can be determined whether the user wants to simulate operations such as pushing the virtual object forward, backward, stopping, or turning. For example, it can be determined what type of road the virtual object is on, whether it has hit a virtual wall, etc. The user's movement intention can be determined through this applied force information and position information. For example, when the user operates the handle 210, if the force sensor 211 detects that the direction of the force is forward and the forward force is maintained or increased, it means that the user wants to continue pushing the virtual object forward; on the contrary, if the direction of the force is opposite to the original direction of movement, it can be inferred that the user wants to control the virtual object to move backward or stop.

[0072] Since the real-time motion of the handle 210 on the magnetic fixed platform 220 is reflected in the target position of the virtual object in the virtual system in the external terminal 100, after determining the user's motion intention when performing the training task, combined with the target position of the virtual object in the virtual system, control information (this control information is information for adjusting the output current of the adjustable power supply 232 in the electrical system 230) can be determined. After the external terminal 100 transmits this control information to the electrical system, the electrical system adjusts the output current of the adjustable power supply 232 according to the control information, thereby adjusting the output magnetic force of the handle 210. For example, if the applied force information indicates that the user currently intends to continue pushing the virtual object forward, and the current target position of the virtual object in the virtual system is at the junction of a cobblestone pavement and grass, then because the grass pavement has greater friction than the cobblestone pavement, in order to push the virtual object forward, the passive force (output force) applied to the user needs to be increased to simulate a more realistic real-world situation. Therefore, it is necessary to increase the output magnetic force of the handle 210 by adjusting the output current of the adjustable power supply 232.

[0073] Based on the above tactile force feedback system, the force feedback adjustment method is described below. The force feedback adjustment method is applied to the external terminal 100 of the above tactile force feedback system. Figure 3 As shown, the force feedback adjustment method includes:

[0074] Step S100 : determining the user's movement intention when performing a training task based on information about the force applied by the user on the handle 210 .

[0075] In step S200 , control information is generated based on the motion intention and the position information of the handle 210 on the magnetic fixed platform 220 .

[0076] The control information is sent to the handle 210 via the electrical system 230 to indicate the output magnetic force of the handle 210 so that the output force matches the intended movement. The applied force information includes the magnitude and direction of the force applied by the user to the armrest 213 of the handle 210.

[0077] For example, the force trend of the applied force can be determined based on the force applied by the user to the armrest portion 213 of the handle 210. For example, if the applied force detected by the force sensor 211 increases, the force trend changes from small to large; if the applied force detected by the force sensor 211 decreases, the force trend changes from large to small; and if the applied force detected by the force sensor 211 remains unchanged, the force trend remains unchanged. After determining the force trend, the direction of the force can be combined with the direction of the force to determine the user's movement intention. For example, when the user operates the handle 210, if the force sensor 211 detects that the applied force is moving forward and increasing, it indicates that the user intends to continue pushing the virtual object forward. Conversely, if the direction of the applied force is opposite to the original direction of the virtual object's movement, it can be inferred that the user intends to push the virtual object backward or stop. It is understood that based on the determined applied force magnitude and direction, the external terminal 100 can analyze the user's movement intention and, based on the movement intention and the position information of the handle 210 on the magnetic fixed platform 220, determine the next required control information.

[0078] In some embodiments, the electrical system 230 includes a positioning sensor 234, which is an infrared positioning sensor 234, and is used to collect real-time position information of the handle 210 on the magnetic fixed platform 220. After the controller 231 of the electrical system 230 receives the position information of the handle 210 on the magnetic fixed platform 220 collected by the positioning sensor 234, it transmits it to the external terminal 100. The external terminal 100 maps the real-time position information of the handle 210 on the magnetic fixed platform 220 to the target position of the virtual object in the virtual system.

[0079] Furthermore, based on the above-determined motion intention and the current target position of the virtual object in the virtual system, control information for adjusting the magnetic force output by the handle 210 can be determined. For example, if the current target position of the virtual object in the virtual system is at a virtual wall, and if the applied force obtained by the force sensor 211 continues to increase and the direction is to continue moving forward, it will be determined that the user intends to push the virtual object to continue to hit the wall or see if it can pass through the virtual wall. At this time, due to hitting the wall or passing through the virtual wall, the resistance of the virtual wall will be relatively large. Therefore, in order to simulate the normal scene of encountering an obstacle in a real scene, this embodiment needs to output control information to increase the passive force, that is, increase the output force. For another example, if the current target position of the virtual object in the virtual system is the junction of a road surface with greater friction and a road surface with less friction, and it is moving from a road surface with greater friction to a road surface with less friction, the magnitude of the applied force detected by the force sensor 211 remains unchanged or increases, and the direction of the applied force continues to move forward, then it means that the user needs to continue simulating pushing the object from a road surface with greater friction to a road surface with less friction. At this time, in the real situation, the force used to push an object on a road surface with less friction is smaller than that used to push an object on a road surface with greater friction. Therefore, after determining the intention of movement, the output force will be adjusted according to the actual situation to reduce the output force.

[0080] In some embodiments, the output force is determined based on the friction factor between the handle 210 and the magnetic fixed platform 220, the vertical force applied by the user to the magnetic fixed platform 220 through the handle 210, the gravity of the handle 210, and the output magnetic force of the electromagnet 212 in the handle 210.

[0081] The output force can be calculated by the following formula: Where, is the friction factor of the electromagnet 212, The vertical force applied by the user on the magnetic fixed platform 220 through the handle 210, is the gravity of the handle 210, is the output magnetic force of the electromagnet 212 in the handle 210.

[0082] Since the gravity of the handle 210 is fixed when adjusting the output force, the vertical force applied by the user to the magnetic fixed platform 220 through the handle 210 can be collected by the force sensor 211. Therefore, when the gravity of the handle 210 and the vertical force applied by the user to the magnetic fixed platform 220 through the handle 210 are fixed, if you want to adjust the output force, you only need to adjust the output magnetic force of the electromagnet 212 in the handle 210. The adjustment of the output magnetic force is adjusted by adjusting the applied control current. However, there is no simple linear relationship between the output magnetic force of the electromagnet 212 and the applied control current, and it is impossible to directly achieve precise control of the output electromagnetic force through the control signal. This embodiment is achieved by Figure 4 The steps shown are used to perform closed-loop control of the output force. Figure 4 include:

[0083] Step S210 : determining an adjustment amount for the current output current of the adjustable power supply 232 according to the difference between the output force and the expected output force.

[0084] In step S220, the control information is updated according to the adjustment amount to generate new control information, and the new control information is sent to the electrical system 230 so that the electrical system 230 adjusts the output current of the adjustable power supply 232 according to the new control information, thereby adjusting the output magnetic force of the handle 210.

[0085] In step S230 , a new output force is determined based on the adjusted output magnetic force, the vertical force applied by the handle 210 on the magnetic fixed platform 220 , and the gravity of the handle 210 , until the difference between the output force and the expected output force is within a preset difference range.

[0086] Demonstratively, this embodiment aims to provide force feedback training that is more in line with actual needs. In a typical force feedback system, the flow of energy in the virtual environment is divided into three directions: kinetic energy, potential energy, and dissipated energy (heat energy, light energy, etc.). Since the passive system only has energy dissipation characteristics and cannot simulate energy storage elements such as springs, the energy flow in the virtual environment of the passive tactile force feedback system of this embodiment is only dissipated and converted into kinetic energy. From the perspective of the implementation of tactile force feedback, force output is a response to the user's input action and needs to match the design requirements of the tactile feedback model. Therefore, this embodiment divides the models in the passive tactile force feedback system into two categories: models that only dissipate energy and models with kinetic energy conversion.

[0087] Models that only dissipate energy are characterized by the fact that the energy input into the virtual environment is completely dissipated. Combined with task-oriented requirements, this type of model is mainly used to simulate resistance feedback task scenarios in users' daily lives. The core of this force feedback model lies in the stability of the output and the ability to dynamically adjust. Based on the power dissipated by the virtual environment of the user's input energy, it is further divided into two typical models: friction model: This model continuously dissipates energy during the user's movement, and the resistance output is relatively stable to simulate the change in resistance when sliding on surfaces of different materials; virtual wall model: This model dissipates energy in the short period of time when the user collides with the boundary, and the resistance output needs to increase rapidly in a very short time to simulate the obstruction of movement by a rigid wall.

[0088] The characteristic of the model with kinetic energy conversion is that the energy is not dissipated immediately, and part of the input energy is converted into the kinetic energy of other objects in the virtual environment. This type of model is mostly used to simulate the interaction between the user and the object, and to express the motion characteristics of the object through the robot system 200. From the perspective of task orientation, this type of model is suitable for simulating tasks in daily life that come into contact with objects and change the motion state of the objects. The model can be a virtual rigid body model. In the virtual rigid body model, part of the energy input by the user into the virtual environment is converted into the kinetic energy of the virtual object that collides with the controlled virtual object. Its resistance output characteristics include the peak change of the instantaneous impact force output, the subsequent motion resistance output, etc., to simulate the tactile force feedback of the virtual rigid body during the collision.

[0089] Because the output magnetic force of electromagnet 212 and the applied control current are not in a simple linear relationship, precise control of the output electromagnetic force cannot be achieved directly through the control signal. Therefore, in this embodiment, the output force needs to be adjusted to ensure that the difference between the output force and the expected output force is within a preset difference range. The expected output force is the output force required to perform the training task corresponding to a certain model. The expected output force corresponding to each model can be quantitatively calculated.

[0090] The friction model is designed to simulate the friction changes when a virtual object slides between surfaces of different materials in a virtual environment. The overall expected output force F is expressed by Formula 2, which is: ;In formula 2, is the sum of the gravity of the handle 210 and the vertical force exerted by the handle 210 on the magnetic fixed platform 220, is the projection area of the virtual object in area A, is the friction coefficient of area A, is the projection area of the virtual object in area B, is the friction coefficient of region B.

[0091] Figure 5A schematic diagram of the friction model of this embodiment is shown in FIG. Figure 5 As shown, area A is a grassland area. is the projection area of the virtual object on the grass area, is the friction coefficient of the grass area, and area B is the stone slab area, then is the projection area of the virtual object on the slate area, is the friction coefficient of the slab area.

[0092] For the virtual wall model, the model is designed to simulate the force feedback performance of a virtual object when it contacts a rigid surface. In this embodiment, motion intention recognition is added to the model to determine whether the virtual object is trying to leave the wall or further penetrate the wall, thereby dynamically switching between high and low resistance. When the controlled virtual object collides with the virtual wall model, the system combines the motion intention of the controlled virtual object to make a judgment. When the force applied to the virtual object is directed toward the inside of the wall, the system will apply a larger feedback force. (greater than 15N) to prevent the controlled object from further penetrating the wall; otherwise, the system applies a smaller force (The current ground corresponds to friction), making it easier for the virtual object to break away from the wall. The overall expected output force under this model is expressed by Formula 3, which is: , in the formula and .

[0093] The virtual rigid body model is suitable for simulating the task of a virtual object coming into contact with an object in daily life and changing the object's motion state. The core physical quantity of the virtual rigid body model when simulating a collision is the collision force (especially the peak collision force). In this embodiment, its value is estimated based on the collision contact stiffness and collision velocity. In a completely inelastic collision, the peak collision force is It is a key indicator reflecting the force at the moment of collision. It can be used as the expected output force of the virtual rigid body model. ; In the formula, k is the contact stiffness and v is the collision velocity.

[0094] This embodiment employs the aforementioned three task-oriented force feedback models (friction model, virtual wall model, and virtual rigid body model) within a virtual environment to simulate diverse rehabilitation scenarios. This allows for greater diversity in force feedback training tasks and provides more accurate and effective feedback tailored to specific tasks. By combining task-oriented passive force feedback within a virtual environment, the system can simulate tasks reminiscent of everyday life (such as mopping the floor and pushing boxes), enhancing the effectiveness of force feedback training and helping improve patients' motor function recovery.

[0095] The following combination Figure 6 The output force adjustment process of this embodiment is described.

[0096] When simulating a certain display scene task, after determining the control information according to the movement intention and the current target position, the output current of the adjustable power supply 232 is adjusted based on the control information, thereby adjusting the output magnetic force of the electromagnet 212 in the handle 210. Then, based on the adjusted output magnetic force combined with the vertical force applied by the user through the handle 210 on the magnetic fixed platform 220 and the weight of the handle 210, the current output force (i.e., the actual output force) is calculated, and then the output force is compared with the expected output force to obtain the output force difference e, i.e., e = Fd – F; wherein Fd is the expected output force and F is the output force.

[0097] If the calculated difference in output force is not within the preset difference range, it means that the actual output force is too far from the expected output force. In order to make the training more realistic, the adjustment amount of the current output current of the adjustable power supply 232 is determined based on the difference. Among them, the expected output force is calculated based on the expected output force calculation formula of the model corresponding to the current training task. In this embodiment, when adjusting the adjustment amount of the output current, a PID controller is used. The control amount of the output current is based on the difference between the output force and the expected output force, combined with the proportional integral differential control algorithm to determine the adjustment amount of the current output current of the adjustable power supply 232. The calculation formula of the adjustment amount is: Where, is the proportional gain; is the integral gain; is the differential gain; u is the adjustment amount.

[0098] After calculating the adjustment amount, new control information is generated based on the adjustment amount and sent to the controller 231 of the electrical system 230. The controller 231 of the electrical system 230 adjusts the output current of the adjustable power supply 232 based on the received new control information, thereby re-adjusting the output magnetic force of the electromagnet 212 of the handle 210. After the output magnetic force is adjusted, a new output force is again determined based on the adjusted output magnetic force, the vertical force applied by the handle 210 on the magnetic fixed platform 220, and the gravity of the handle 210, until the difference between the output force and the desired output force is within a preset difference range.

[0099] like Figure 7 As shown, the present application proposes a force feedback adjustment method, which is applied to the external terminal and the robot system in the above-mentioned tactile force feedback system. The virtual system of the external terminal includes a preset training task. The force feedback adjustment method includes:

[0100] Step S10: The robot system sends information about the force applied by the user to the handle and information about the position of the handle on the magnetic fixed platform to an external terminal;

[0101] Step S20: The external terminal determines the user's movement intention when performing the training task based on the applied force information, and generates control information based on the movement intention and the position information of the handle on the magnetic fixed platform;

[0102] The control information is sent to the handle through the electrical system in the robot system to indicate the output magnetic force of the handle so that the output force matches the movement intention.

[0103] It should be noted that the optional items in the above embodiments are also applicable to this embodiment, so they will not be described again here.

[0104] This application proposes a tactile force feedback system and force feedback adjustment method based on magnetic braking. This system and method, combined with task-oriented training in a virtual environment, can adjust passive force (output force) feedback in real time, making force feedback training more tailored to the user's actual needs. The tactile force feedback system of this application includes an external terminal 100 with a virtual system and a robot system 200. The robot system 200 includes a handle 210, a magnetic fixed platform 220, and an electrical system 230. An electromagnet 212 is provided on the handle 210, which contacts the magnetic fixed platform 220 through the electromagnet 212, forming a magnetic circuit. The electrical system includes an adjustable power supply 232, which is used to adjust the input current of the electromagnet 212 to achieve dynamic changes in the output magnetic force of the electromagnet 212, and thus in the friction between the electromagnet 212 and the magnetic fixed platform 220. This application uses magnetic braking to adjust passive force (output force) feedback, avoiding the impact risk associated with active rehabilitation robot motor drive methods and ensuring the safety of the training process. The tactile force feedback system and force feedback adjustment method of the present application adopt a closed-loop control architecture, with the controller 231 of the electrical system 230 as the core, to collect the user's movement intention and movement position data in real time, and transmit it to the external terminal 100 for calculation and analysis. The external terminal 100 generates a real-time control signal based on the PID control algorithm in combination with the needs of force feedback training, and adjusts the output current of the adjustable power supply 232 through the controller 231 of the electrical system 230, thereby dynamically adjusting the output magnetic force of the electromagnet 212 to achieve real-time and accurate output force feedback regulation. Through closed-loop control, the system can continuously adjust the magnitude of the feedback force according to the user's training goals to make the output force more accurate. At the same time, the PID control algorithm can compensate for interference, improve the dynamic response performance of force feedback, and ensure the training effect of different rehabilitation stages. In addition, the present application designs multiple task-oriented force feedback models in a virtual environment, such as friction model, virtual wall model and virtual rigid body model, to simulate different training scenarios. Through task design in a virtual environment, such as simulating tasks in daily life (mopping the floor, pushing boxes, etc.), dynamically mapping the user's actual movement position and virtual display position, adjusting feedback resistance in real time, simulating different physical properties such as friction, virtual walls, etc., the realism of rehabilitation training can be enhanced.

[0105] The present application also provides a terminal device. Exemplarily, the terminal device includes a processor and a memory, wherein the memory stores a computer program, and the processor runs the computer program, thereby enabling the terminal device to execute the above-mentioned force feedback adjustment method.

[0106] The processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, including at least one of a central processing unit (CPU), a graphics processing unit (GPU), a network processor (NP), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor, etc., and can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application.

[0107] The memory may be, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), and electrically erasable programmable read-only memory (EEPROM). The memory is used to store computer programs, and the processor can execute the computer programs accordingly after receiving an execution instruction.

[0108] This application also provides a computer-readable storage medium for storing the computer program used in the terminal device. For example, the computer-readable storage medium may include, but is not limited to, various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0109] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or flowchart, and the combination of boxes in the structure diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0110] In addition, the functional modules or units in the various embodiments of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0111] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a smart phone, personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0112] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the scope of protection of the present application.

Claims

1. A tactile force feedback system, characterized in that: include: An external terminal with a virtual system and a robot system; the robot system includes a handle, a magnetic fixed platform and an electrical system; The handle is disposed on the magnetic fixed platform, and a magnetic circuit is formed between the handle and the magnetic fixed platform for providing an output force feedback to the user; wherein the output force is determined based on a friction factor between the handle and the magnetic fixed platform, a vertical force applied by the user on the magnetic fixed platform through the handle, the gravity of the handle, and the output magnetic force of the electromagnet in the handle; The electrical system is connected to the handle and is used to collect position information of the handle on the magnetic fixed platform in real time; The external terminal is connected to the electrical system, and is used to determine control information based on the position information and the user's applied force information, and send the control information to the electrical system so that the electrical system adjusts the output magnetic force of the handle according to the control information, thereby matching the output force with the movement intention; wherein, the movement intention is determined based on the force information applied by the user on the handle when the user performs a training task.

2. The tactile force feedback system according to claim 1, wherein: The handle includes a force sensor, an electromagnet and an armrest; The force sensor and the electromagnet are arranged below the armrest portion; The force sensor is used to obtain the applied force information applied by the user to the armrest portion; wherein the applied force information includes the applied force applied by the user to the armrest portion of the handle and the direction of the applied force; The electromagnet is used to form a closed magnetic circuit with the armature part of the magnetic fixed platform to generate the output force.

3. The tactile force feedback system according to claim 2, wherein: The electrical system includes: a controller, an adjustable power supply and a positioning sensor; The positioning sensor is used to collect position information of the handle on the magnetic fixed platform; The controller is configured to receive the position information sent by the positioning sensor and send the position information to the external terminal; wherein the position information is used to instruct a virtual object in a virtual system built into the external terminal to maintain synchronization with the position of the handle; The controller is further configured to adjust the adjustable power supply according to the received control information so as to adjust the magnetic force of the electromagnet.

4. A force feedback adjustment method, characterized in that: The external terminal used in the tactile force feedback system according to any one of claims 1 to 3, wherein the virtual system of the external terminal includes a preset training task, and the force feedback adjustment method includes: determining, based on information about the force applied by the user on the handle, the user's movement intention when performing the training task; Control information is generated based on the movement intention and the position information of the handle on the magnetic fixed platform; wherein, the control information is sent to the handle through the electrical system to indicate the output magnetic force of the handle so that the output force matches the movement intention.

5. The force feedback adjustment method according to claim 4, characterized in that: The applied force information includes the applied force applied by the user to the armrest portion of the handle and the direction of the applied force; The determining, based on the force information applied by the user on the handle, the movement intention of the user when performing the training task includes: The movement intention of the user when performing the training task is determined based on the force applied by the user to the armrest of the handle and the direction of the applied force; wherein the movement intention includes moving forward, moving backward, turning and stopping.

6. The force feedback adjustment method according to claim 5, characterized in that: The generating of control information based on the motion intention and the position information of the handle on the magnetic fixed platform includes: Mapping the position information of the handle on the magnetic fixed platform obtained in real time to the target position of the virtual object in the virtual system; The control information is determined based on the motion intention and the target position of the virtual object in the virtual system; wherein the control information includes adjustment information for the output current of the adjustable power supply in the electrical system.

7. The force feedback adjustment method according to claim 4, characterized in that: After the control information is generated based on the motion intention and the position information of the handle on the magnetic fixed platform, the method further includes: determining an adjustment amount for a current output current of the adjustable power supply according to a difference between the output force and a desired output force; updating the control information according to the adjustment amount to generate new control information, and sending the new control information to the electrical system so that the electrical system adjusts the output current of the adjustable power supply according to the new control information, thereby adjusting the output magnetic force of the handle; A new output force is determined based on the adjusted output magnetic force, the vertical force applied by the handle on the magnetic fixed platform, and the gravity of the handle until the difference between the output force and the expected output force is within a preset difference range.

8. The force feedback adjustment method according to claim 7, characterized in that: The determining of the adjustment amount of the current output current of the adjustable power supply according to the difference between the output force and the expected output force includes: Determining an adjustment amount for a current output current of the adjustable power supply based on a difference between the output force and a desired output force in combination with a proportional-integral-differential control algorithm; The calculation formula of the adjustment amount is: Where, is the proportional gain; is the integral gain; is the differential gain; u is the adjustment amount; e is the difference between the output force and the expected output force.

9. A force feedback adjustment method, characterized in that: The external terminal and the robot system used in the tactile force feedback system according to any one of claims 1 to 3, wherein the virtual system of the external terminal includes a preset training task, and the force feedback adjustment method includes: The robot system sends information about the force applied by the user on the handle and information about the position of the handle on the magnetic fixed platform to the external terminal; The external terminal determines the user's movement intention when performing the training task based on the applied force information, and generates control information based on the movement intention and the position information of the handle on the magnetic fixed platform; The control information is sent to the handle via the electrical system in the robot system, and is used to indicate the output magnetic force of the handle so that the output force matches the movement intention.

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