Tactile force feedback system and force feedback adjusting method

Abstract

The invention relates to the technical field of rehabilitation training, and discloses a tactile force feedback system and a force feedback adjusting method, and the system comprises an external terminal with a virtual system and a robot system; a magnetic circuit is formed between the handle and the magnetic conductive fixed platform and is used for providing output force; the electrical system is used for collecting motion position information of the handle in real time; the external terminal is used for determining control information according to the position information and the applied force information and sending the control information 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 system and comprises the following steps: determining a motion intention when a user executes a training task according to information of force applied to the handle by the user; generating control information based on the motion intention and the position information of the handle on the magnetic conductive fixed platform; wherein the control information is sent to the handle through the electrical system and used for indicating the output magnetic force of the handle, so that the output force is matched with the motion intention. According to the invention, safe and effective rehabilitation training can be realized.

Description

Technical Field

[0001] This application relates to the technical field of rehabilitation training, and particularly to a tactile force feedback system and a force feedback adjustment method. Background Art

[0002] Currently, the number of patients whose self-care ability has declined due to stroke continues to rise. However, the number of professional rehabilitation personnel has not increased correspondingly. Against this background, rehabilitation equipment has become the main means to assist patients in rehabilitation training. It is worth noting that among stroke patients, those with upper limb motor dysfunction account for a relatively large proportion. Existing upper limb rehabilitation training equipment is mainly divided into two categories: one is an active device driven by a motor, and the other is a passive device driven by a brake. Comparatively speaking, passive rehabilitation training equipment is widely used because it uses a brake with a lower cost and the system has a passivity characteristic (that is, it will not actively provide power to the user), and it has the potential to simulate daily life tasks while ensuring safety.

[0003] However, existing passive rehabilitation training equipment still has the following technical limitations: First, although such equipment can provide a certain amount of force feedback, its resistance output value is relatively single and cannot be continuously and dynamically adjusted according to the patient's real-time motion state and rehabilitation needs, resulting in its difficulty in adapting to the training requirements at different rehabilitation stages; Second, some rehabilitation equipment adjusts the feedback force by replacing counterweights of different weights. This method not only cannot achieve real-time regulation of the feedback force during training but also is difficult to effectively simulate common task scenarios in daily life. These technical defects have restricted the rehabilitation training effect and the patient's rehabilitation process to a certain extent. Summary of the Invention

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

[0005] In a first aspect, the embodiments of this application provide a tactile force feedback system, including: 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 arranged 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; The electrical system is connected to the handle for real-time acquisition of the position information of the handle on the magnetic fixed platform; The external terminal is connected to the electrical system for determining control information according to the position information and the user-applied force information, and sending 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, and further makes the output force match the motion intention.

[0006] In an alternative embodiment, the handle includes a force sensor, an electromagnet, and an armrest portion; The force sensor and the electromagnet are disposed below the armrest portion; The force sensor is configured 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 configured to form a closed magnetic circuit with the armature portion of the magnetically conductive fixed platform to form the output force.

[0007] In an alternative embodiment, the electrical system includes: a controller, an adjustable power supply, and a positioning sensor; The positioning sensor is configured to collect the position information of the handle on the magnetically conductive 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 indicate that the virtual object in the virtual system built in the external terminal is synchronized with the position of the handle; The controller is further configured to adjust the adjustable power supply according to the received control information to adjust the magnetic force of the electromagnet.

[0008] 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 haptic force feedback system as described in any one of the foregoing embodiments. A preset training task is included in the virtual system of the external terminal. The force feedback adjustment method includes: Determine the motion intention of the user when performing the training task according to the applied force information applied by the user to the handle; Generate control information based on the motion intention and the position information of the handle on the magnetically conductive 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 motion intention.

[0009] In an alternative 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; Determining the motion intention of the user when performing the training task according to the applied force information applied by the user to the handle includes: Determine the motion intention of the user when performing the training task according to the applied force applied by the user to the armrest portion of the handle and the direction of the applied force; wherein, the motion intention includes forward, backward, turning, and stopping.

[0010] In an alternative embodiment, generating the control information based on the motion intention and the position information of the handle on the magnetically conductive fixed platform includes: Mapping the position information of the handle on the magnetically conductive fixed platform obtained in real time to the target position of the virtual object in the virtual system; Determining the control information 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.

[0011] In an alternative embodiment, the output force is determined according to the friction factor between the handle and the magnetically conductive fixed platform, the vertical force applied by the user to the magnetically conductive fixed platform through the handle, the gravity of the handle, and the output magnetic force of the electromagnet in the handle.

[0012] In an alternative embodiment, after generating the control information based on the motion intention and the position information of the handle on the magnetically conductive fixed platform, it further includes: Determining the adjustment amount of the current output current of the adjustable power supply according to the difference between the output force and the 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, and further adjusts the output magnetic force of the handle; Determining a new output force according to the adjusted output magnetic force, the vertical force applied by the handle to the magnetically conductive fixed platform, and the gravity of the handle, until the difference between the output force and the desired output force is within a preset difference range.

[0013] In an alternative embodiment, determining the adjustment amount of the current output current of the adjustable power supply according to the difference between the output force and the desired output force includes: determining the adjustment amount of the current output current of the adjustable power supply based on the difference between the output force and the desired output force, in combination with a proportional-integral-derivative control algorithm; The calculation formula for the adjustment amount is:

[0014] In the formula, is the proportional gain; is the integral gain; is the derivative gain; u is the adjustment amount; e is the difference between the output force and the desired output force.

[0015] Thirdly, an embodiment of the present application provides a force feedback adjustment method, which is applied to an external terminal and a robot system in the tactile force feedback system described in any one of the foregoing embodiments. A preset training task is included in the virtual system of the external terminal. The force feedback adjustment method includes: The robot system sends the applied force information applied by the user on the handle and the position information of the handle on the magnetically conductive fixed platform to the external terminal; The external terminal determines the motion intention of the user when performing the training task according to the applied force information, and generates control information based on the motion intention and the position information of the handle on the magnetically conductive fixed platform; Among them, the control information is sent to the handle through 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 motion intention.

[0016] The embodiments of the present application have the following beneficial effects: The tactile force feedback system of the present application includes an external terminal with a virtual system and a robot system; the robot system includes a handle, a magnetically conductive fixed platform and an electrical system. The electrical system can collect the position information of the handle on the magnetically conductive fixed platform, and then send the position information to the external terminal. The external terminal can determine, according to the received position information and the applied force information applied by the user on the handle, the control information for adjusting the output magnetic force of the handle, and send the control information to the electrical system. The electrical system adjusts the output magnetic force of the handle according to the control information. The present application combines task-oriented training in a virtual environment, and can adjust the output force feedback in real time, making the force feedback training more in line with the actual needs of patients. When performing output force feedback, the present application uses the magnetic circuit formed between the handle and the magnetically conductive fixed platform for adjustment, avoiding the impact risk of the motor drive mode of the active rehabilitation robot, and ensuring the safety of the training process. In addition, the system structure of the present application is simple, the cost is low, and it is easy to deploy. It is especially suitable for the home rehabilitation environment, does not require relying on large equipment, and is more convenient to use. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 Shows a schematic structural diagram of the tactile force feedback system of the embodiment of the present application; Figure 2aShows a schematic diagram of the handle structure of this embodiment of the present application; Figure 2b Shows a schematic diagram of the electrical system structure of this embodiment of the present application; Figure 3 Shows a first flowchart of the force feedback adjustment method of this embodiment of the present application; Figure 4 Shows a second flowchart of the force feedback adjustment method of this embodiment of the present application; Figure 5 Shows a scenario schematic diagram of the friction force model of this embodiment of the present application; Figure 6 Shows a schematic diagram of the output force adjustment process of this embodiment of the present application; Figure 7 Shows a third flowchart of the force feedback adjustment method of this embodiment of the present application.

[0019] Main element symbol description: 100 - external terminal; 200 - robot system; 210 - handle; 220 - magnetically conductive fixed platform; 230 - electrical system; 211 - force sensor; 212 - electromagnet; 213 - armrest part; 231 - controller; 232 - adjustable power supply; 233 - DC power supply; 234 - positioning sensor. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

[0021] Generally, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various 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 present application to be protected, but only represents the 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 efforts belong to the scope of protection of the present application.

[0022] Hereinafter, the terms "including", "having" and their cognates that can be used in various embodiments of the present application are only intended to represent specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be construed as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0023] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the present application belong. The terms (such as those defined in a commonly used dictionary) will be interpreted as having the same meaning as the contextual meaning in 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.

[0024] The following will describe in detail some embodiments of the present application with reference to the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments may be combined with each other.

[0025] Stroke not only impairs the cognitive ability of patients, but also leads to the decline of their self-care ability, bringing a heavy burden of rehabilitation and care to the families and society of patients. With the continuous growth of the number of stroke patients globally, the number of rehabilitation therapists has not increased correspondingly, and the one-on-one treatment mode between therapists and patients in traditional rehabilitation has further exacerbated the shortage of stroke treatment resources.

[0026] In rehabilitation training, guiding patients to participate in active movements and feel the external forces on the trunk is an effective way to promote patients' recovery of cognitive ability and re-acquire life skills. In recent years, the application of robot technology in stroke rehabilitation has been increasingly developed. For the upper limb rehabilitation of stroke patients, robots can provide precise and controllable force and tactile rehabilitation training. On this basis, by combining training tasks with feedback such as images and sounds, it can help patients better acquire life skills and ultimately return to society. However, due to the high cost of rehabilitation robots, they are only commonly found in medium and large medical institutions. Rehabilitation robots also face a similar shortage in the number of rehabilitation practitioners, which has led to a lack of in-depth promotion of the treatment modes including force feedback training and task-oriented training they contain. Therefore, it is very important to develop a rehabilitation robot that is suitable for low cost, easy to use, and applicable to community or home scenarios for the rehabilitation training of stroke patients.

[0027] According to the driving mode, rehabilitation robots can be classified into active ones driven by motors and passive ones driven by brakes. The brakes used in passive robots have lower costs, and their systems are passive, which do not provide power to users. They have both safety and the potential to simulate life tasks, so they are expected to be used for home rehabilitation. However, the existing rehabilitation equipment still has limitations in the regulation of passive force feedback under task orientation. Especially in the home rehabilitation scenario, these devices have insufficient ability to dynamically adjust the passive force output according to task requirements and limited ability to simulate daily life tasks, which is not conducive to the effect of patients' force feedback training. Therefore, the present invention proposes a tactile force feedback system and a force feedback regulation method, enabling users (patients) to adjust the passive force feedback in real time during rehabilitation training and more realistically simulate common tasks in daily life by combining task-oriented training in a virtual system (such as mopping the floor, pushing a box, etc.), thereby helping patients recover motor function more effectively.

[0028] The tactile force feedback system of the present application will be described below in conjunction with some specific embodiments.

[0029] As Figure 1 shown, the tactile force feedback system includes: an external terminal 100 with a virtual system and a robot system 200.

[0030] Exemplarily, the virtual system is developed based on a real-time 3D interactive content creation and operation platform (such as Unity) and is used to simulate a virtual environment for moving objects with both hands. The virtual environment includes virtual objects and virtual scenes. The virtual scenes include, but are not limited to, grounds with different friction coefficients (such as grasslands, asphalt roads, brick roads, dirt roads, etc.) and virtual walls (which can be used to simulate the scenario when pushing an object to a wall). The virtual objects can be spherical objects, square objects, etc. The virtual system can be installed on the external terminal 100, and the external terminal 100 can be a computer, a host computer, an IPAD, etc.

[0031] To ensure the task orientation of the training and make the training more planned, preset training tasks can be pre-set in the virtual system. For example, a task of pushing an object can be designed in the virtual system. The user needs to control the virtual object to push the virtual object (such as a box, a ball, etc.) in the virtual environment to a specified position by moving the handle 210. When the patient pushes the virtual object towards the final position, different resistance areas will be set on the path. The external terminal 100 calculates the moving position of the object and the force applied by the user to generate corresponding control signals, which are transmitted 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.

[0032] Through this virtual system, it can be used for, but not limited to, friction force model training, virtual wall model training, virtual rigid body model training, etc. For the friction force model, in the virtual system, this model aims to simulate the friction changes when a virtual object slides between different materials or the same material surfaces, such as when a moving object moves from a grassy area to a stone slab area. For the virtual wall model, this model aims to simulate the force feedback performance when an object 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, so as to dynamically switch between high and low resistances. When the virtual object collides with the virtual wall model, the system makes a judgment in combination with the motion intention of the control object. When the force applied to the control object is towards the inside of the wall, the system will apply a relatively large feedback force (for example, a force greater than 15 N) to prevent the control object from further penetrating the wall; conversely, the system will apply a relatively small force (for example, the corresponding friction force of the current ground) to control the object to more easily leave the wall. For the virtual rigid body model, this model is suitable for simulating tasks in daily life that contact an object and change the object's motion state.

[0033] Such as Figure 1 、 Figure 2a 、 Figure 2b As shown, the robot system 200 includes a handle 210, a magnetically conductive fixed platform 220, and an electrical system 230.

[0034] The handle 210 is arranged on the magnetically conductive fixed platform 220, and a magnetic circuit is formed between the handle 210 and the magnetically conductive fixed platform 220 for providing an output force feedback to the user.

[0035] Exemplarily, the handle 210 includes a force sensor 211, an electromagnet 212, and an armrest part 213; when the handle 210 is placed on the magnetically conductive fixed platform 220, the force sensor 211 and the electromagnet 212 are arranged below the armrest part 213; the force sensor 211 and the electromagnet 212 are connected by a connecting plate. The armrest part 213 is the position that directly contacts the user's hand when the user performs rehabilitation training through this tactile force feedback system. The force sensor 211 is used to obtain the applied force and the direction of the applied force exerted by the user on the armrest part 213. The electromagnet 212 is used to form a closed magnetic circuit with the armature part of the magnetically conductive fixed platform 220 to form an output force.

[0036] The magnetically conductive fixed platform 220 is used to provide the working space and magnetic force output of the robot system 200. The magnetically conductive fixed platform 220 includes a bottom plate (the bottom plate can be a plate made of 20# steel with its surface chrome-plated) and a cover plate (acrylic). The bottom plate serves as the armature part of the electromagnet 212 and together with the electromagnet 212 provides the output force of the system. The cover plate is used to fix the position sensor 234.

[0037] The electrical system 230 is connected to the handle 210. The handle 210 and the electrical system 230 are flexibly connected by a spring wire to achieve the transmission of signals and power, and are used to collect the position information of the handle 210 on the magnetically conductive fixed platform 220 in real time. The handle 210 corresponds to a virtual object in the virtual system. After the electrical system 230 collects the position information of the handle 210 on the magnetically conductive fixed platform 220, it is fed back to the virtual system, and the virtual object in the virtual system moves in the virtual environment according to the moving position of the handle 210.

[0038] Specifically, the electrical system 230 includes: a controller 231, an adjustable power supply 232, and a positioning sensor 234 (not shown in the figure); the positioning sensor 234 is used to collect the position information of the handle 210 on the magnetically conductive fixed platform 220, and send the position information to the external terminal 100 through the controller 231, so that the virtual object in the virtual system built in the external terminal 100 is synchronized with the position of the handle 210; the controller 231 is further used to adjust the adjustable power supply 232 according to the received control information to adjust the magnetic force of the electromagnet 212. Among them, the control information includes the adjustment information of the output current of the adjustable power supply 232 in the electrical system 230. The electrical system 230 further includes a DC power supply 233, and the DC power supply 233 is used to supply power to the controller 231 and other components.

[0039] The external terminal 100 is connected to the electrical system 230, and is used to determine the control information according to the position information and the 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, so as to make the output force match the motion intention.

[0040] Demonstratively, the applied force information includes the applied force and the direction of the applied force applied by the user on the armrest portion 213 of the handle 210. According to the applied force and the direction of the applied force applied by the user on the armrest portion 213 of the handle 210, it is possible to determine operations such as the user wanting to simulate pushing the virtual object forward, backward, stopping, or turning. For example, it is possible to determine on what type of road surface the virtual object is and whether it hits a virtual wall. Through these applied force information and position information, the user's motion intention can be determined. 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 remains or increases, it means that the user wants to continue to push the virtual object forward; on the contrary, if the direction of the force is opposite to the original motion direction, it can be inferred that the user wants to control the virtual object to retreat or stop.

[0041] Since the real-time movement process of the handle 210 on the magnetically conductive fixed platform 220 will be reflected in the target position of the virtual object in the virtual system in the external terminal 100, after determining the movement intention of the user when performing the training task and combining it with the target position of the virtual object in the virtual system, the control information (the control information is the adjustment information for the output current of the adjustable power supply 232 in the electrical system 230) can be determined. After the external terminal 100 sends the 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 realizing the adjustment of the output magnetic force of the handle 210. For example, if it is speculated from the applied force information that the user currently wants to continue to push the virtual object forward, and the current target position of the virtual object in the virtual system is the junction of the stone pavement and the grassland, then since the friction force of the grassland pavement is greater than that of the stone pavement, if the virtual object is to be pushed forward, the passive force (output force) applied to the user needs to be increased, so as to simulate a more realistic real 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.

[0042] Based on the above haptic force feedback system, the force feedback adjustment method will be described below. The force feedback adjustment method is applied to the external terminal 100 of the above haptic force feedback system. As Figure 3 shown, the force feedback adjustment method includes: Step S100, determine the movement intention of the user when performing the training task according to the applied force information applied by the user on the handle 210.

[0043] Step S200, generate control information based on the movement intention and the position information of the handle 210 on the magnetically conductive fixed platform 220.

[0044] Among them, the control information is sent to the handle 210 through the electrical system 230 to indicate the output magnetic force of the handle 210, so that the output force matches the movement intention. The applied force information includes the magnitude and direction of the applied force applied by the user on the armrest part 213 of the handle 210.

[0045] Exemplarily, the force trend of the applied force can be determined according to the applied force exerted by the user on 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; if the magnitude of the applied force detected by the force sensor 211 remains unchanged, the force trend remains unchanged. After determining the force trend, the user's motion intention can be judged in combination with the direction of the force. For example, when the user operates the handle 210, if the force sensor 211 detects that the direction of the applied force is forward and increasing, it means that the user wants to continue to push the virtual object forward; on the contrary, if the direction of the applied force is opposite to the original motion direction of the virtual object, it can be inferred that the user wants to push the virtual object backward or stop. It can be understood that based on the determined magnitude and direction of the applied force, the external terminal 100 can analyze the user's motion intention, and the next required control information can be determined according to the motion intention in combination with the position information of the handle 210 on the magnetically conductive fixed platform 220.

[0046] In some embodiments, the electrical system 230 includes a positioning sensor 234, which is an infrared positioning sensor 234 for real-time acquisition of the position information of the handle 210 on the magnetically conductive fixed platform 220. After the controller 231 of the electrical system 230 receives the position information of the handle 210 on the magnetically conductive fixed platform 220 collected by the positioning sensor 234, it is transmitted to the external terminal 100, and the external terminal 100 maps the real-time acquired position information of the handle 210 on the magnetically conductive fixed platform 220 to the target position of the virtual object in the virtual system.

[0047] Further, based on the determined motion intention described above and the current target position of the virtual object in the virtual system, the 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 the 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 wants to push the virtual object to continue hitting 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 this embodiment, in order to simulate the normal scenario when encountering an obstacle in the real world, control information needs to be output to increase the passive force, that is, increase the output force. Another example is that if the current target position of the virtual object in the virtual system is at the junction of a road surface with a large friction coefficient and a road surface with a small friction coefficient, and when moving from the road surface with a large friction coefficient to the road surface with a small friction coefficient, if 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 be forward, it means that the user needs to continue to simulate pushing an object from the road surface with a large friction coefficient to the road surface with a small friction coefficient. At this time, in the real situation, because pushing an object on the road surface with a small friction coefficient requires less force than pushing an object on the road surface with a large friction coefficient, after determining the motion intention, the output force will be adjusted according to the actual situation to reduce the output force.

[0048] In some embodiments, the output force is determined based on the friction factor between the handle 210 and the magnetically conductive fixed platform 220, the vertical force applied by the user to the magnetically conductive 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.

[0049] Its output force can be calculated by the following formula (1), and formula (1) is: ; where is the friction factor of the electromagnet 212, is the vertical force applied by the user to the magnetically conductive 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.

[0050] Since the gravity of the handle 210 is fixed when adjusting the output force, the force in the vertical direction applied by the user to the magnetically conductive fixed platform 220 through the handle 210 can be acquired by the force sensor 211. Therefore, when the gravity of the handle 210 and the force in the vertical direction applied by the user to the magnetically conductive fixed platform 220 through the handle 210 are fixed, if the output force needs to be adjusted, only the output magnetic force of the electromagnet 212 in the handle 210 needs to be adjusted. The adjustment of its output magnetic force is regulated by adjusting the applied control current. However, the relationship between the output magnetic force of the electromagnet 212 and the applied control current is not a simple linear relationship, and the precise regulation of the output electromagnetic force cannot be directly achieved through the control signal. This embodiment performs closed-loop control on the output force through the steps as shown in Figure 4 to achieve closed-loop control of the output force, Figure 4 including: Step S210, determining the adjustment amount of the current output current of the adjustable power supply 232 according to the difference between the output force and the desired output force.

[0051] Step S220, updating the control information according to the adjustment amount to generate new control information, and sending the new control information 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, and further adjusts the output magnetic force of the handle 210.

[0052] Step S230, determining the new output force according to the adjusted output magnetic force, the force in the vertical direction applied by the handle 210 to the magnetically conductive fixed platform 220, and the gravity of the handle 210 until the difference between the output force and the desired output force is within the preset difference range.

[0053] Exemplarily, this embodiment aims to provide force feedback training that better meets the actual needs. Generally, in a 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 the characteristic of energy dissipation and cannot simulate energy storage elements such as springs, in the virtual environment of the passive haptic force feedback system of this embodiment, the energy flow mode is only dissipation and conversion into kinetic energy. From the perspective of the implementation of haptic force feedback, force output is a response to the user's input action and needs to match the design requirements of the haptic feedback model. Therefore, this embodiment divides the models in the passive haptic force feedback system into two categories: models that only dissipate energy and models with kinetic energy conversion.

[0054] The characteristics of the energy-dissipating-only model are that the energy input into the virtual environment is completely manifested in the form of dissipation. Combining with the task-oriented requirements, such models are mainly used to simulate the resistance feedback task scenarios of users in daily life. The core of this force feedback model lies in the stability of the output and the ability of dynamic adjustment. According to the dissipation power of the virtual environment for the energy input by the user, it is further subdivided into two typical models: Friction model: This model continuously dissipates energy during the user's movement, and the resistance output is relatively stable, so as to simulate the resistance changes when sliding on surfaces of different materials; Virtual wall model: This model dissipates energy within a short time when the user collides with the boundary, and the resistance output needs to increase rapidly within an extremely short time, so as to simulate the obstruction of the rigid wall to the movement. The characteristics of the model with kinetic energy conversion are that the energy will not be completely dissipated immediately, and part of the input energy is converted into the kinetic energy of other objects in the virtual environment. Such models are mostly used to simulate the interaction between users and objects, and the movement characteristics of the objects are demonstrated through the robot system 200. From the perspective of task orientation, such models are suitable for simulating tasks in daily life where contact with objects occurs and the movement state of the objects is changed. This 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, and its resistance output characteristics include the peak change of the instantaneous impact force output, the subsequent movement resistance output, etc., so as to simulate the tactile force feedback during the collision of the virtual rigid body.

[0055] Since there is no simple linear relationship between the output magnetic force of the electromagnet 212 and the applied control current, it is impossible to directly achieve precise regulation of the output electromagnetic force through the control signal. Therefore, in this embodiment, the output force also needs to be adjusted to ensure that the difference between the output force and the desired output force is within the preset difference range. Among them, the desired output force is the output force required when performing the training task corresponding to a certain model, and the desired output force corresponding to each model can be quantitatively calculated.

[0056] For the friction model, in the virtual environment, this model aims to simulate the friction changes when the virtual object slides between surfaces of different materials. The overall desired output force F is represented by Formula 2, and Formula 2 is: ; in Formula 2, is the sum of the gravity of the handle 210 and the force exerted by the handle 210 on the magnetically conductive fixed platform 220 in the vertical direction, is the projected area of the virtual object in area A, is the friction coefficient of area A, is the projected area of the virtual object in area B, is the friction coefficient of area B.

[0057] Figure 5The scenario schematic diagram of the friction force model in this embodiment is shown. As Figure 5 shown, area A is the grass area, then is the projected area of the virtual object in the grass area, is the friction coefficient of the grass area. Area B is the slate area, then is the projected area of the virtual object in the slate area, is the friction coefficient of the slate area.

[0058] For the virtual wall model, this model aims to simulate the force feedback performance when a virtual object contacts a rigid surface. In this embodiment, motion intention recognition is added to this model to judge whether the virtual object is trying to leave the wall or further penetrate the wall, so as to dynamically switch between high and low resistances. When the virtual object collides with the virtual wall model, the system combines and judges the motion intention of the virtual object. When the force applied to the virtual object is towards the inside of the wall, the system will apply a larger feedback force (greater than 15 N) to prevent the controlled object from further penetrating the wall; on the contrary, the system will apply a smaller force (the corresponding ground friction at present), making it easier for the virtual object to leave the wall. The overall expected output force in this model is expressed by Formula 3. Formula 3 is: , in the formula and .

[0059] For the virtual rigid body model, this model is suitable for simulating the tasks of a virtual object contacting an object in daily life and changing the motion state of the object. The core physical quantity of the virtual rigid body model in simulating collisions is the collision force (especially the peak collision force). In this embodiment, its value is estimated based on the collision contact stiffness and the collision speed. In a completely inelastic collision, the peak collision force is a key index reflecting the force acting at the moment of collision, and its can be used as the expected output force of the virtual rigid body model. This ; in the formula, k is the contact stiffness and v is the collision speed.

[0060] In this embodiment, the above three task-oriented force feedback models (friction force model, virtual wall model, and virtual rigid body model) are designed in the virtual environment to simulate different rehabilitation scenarios, making the force feedback training tasks more diverse and providing more accurate and effective feedback for specific tasks. By combining the task-oriented passive force feedback of the virtual environment, the system can simulate some tasks close to daily life (such as mopping the floor, pushing a box, etc.), enhance the effectiveness of the force feedback training, and help improve the recovery effect of the patient's motor function.

[0061] The following will describe the output force adjustment process of this embodiment in combination with Figure 6 for illustration.

[0062] When simulating a display scene task, after determining the control information according to the motion intention and the current target position, the output current of the adjustable power supply 232 is adjusted based on the control information, so as to adjust 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 on the magnetically conductive fixed platform 220 through the handle 210 and the weight of the handle 210, the current output force (i.e., the actual output force) is calculated. Then, the output force is compared with the desired output force to obtain the difference e of the output force, that is, e = Fd – F; where Fd is the desired output force and F is the output force.

[0063] If the calculated difference of the output force is not within the preset difference range, it means that the gap between the actual output force and the desired output force is too large. In order to make the training more in line with reality, the adjustment amount of the current output current of the adjustable power supply 232 is determined according to the difference. Among them, the desired output force is calculated according to the desired 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, and the control amount for adjusting the output current is based on the difference between the output force and the desired output force, combined with the proportional-integral-derivative 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: ; in the formula, is the proportional gain; is the integral gain; is the derivative gain; u is the adjustment amount.

[0064] After calculating the adjustment amount, new control information is generated according to 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, so as to realize the re-adjustment of the output magnetic force of the electromagnet 212 of the handle 210. After adjusting the output magnetic force, the new output force is determined again according to the adjusted output magnetic force, the vertical force applied by the handle 210 on the magnetically conductive fixed platform 220, and the gravity of the handle 210 until the difference between the output force and the desired output force is within the preset difference range.

[0065] As Figure 7 shown, the present application proposes a force feedback adjustment method, which is applied to the external terminal and the robot system in the above tactile force feedback system. The virtual system of the external terminal includes a preset training task. The force feedback adjustment method includes: Step S10, the robot system sends the applied force information applied by the user on the handle and the position information of the handle on the magnetically conductive fixed platform to the external terminal; Step S20: The external terminal determines the user's motion intention when performing the training task according to the applied force information, and generates control information based on the motion intention and the position information of the handle on the magnetically conductive fixed platform. 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 motion intention.

[0066] It should be noted that the optional items in the above embodiments are also applicable to this embodiment, so they will not be described repeatedly here.

[0067] The present application proposes a tactile force feedback system and a force feedback adjustment method based on magnetic attraction braking. The system and method combine task-oriented training in a virtual environment, and can adjust the passive force (output force) feedback in real time, making the force feedback training more in line with the actual needs of users. The tactile force feedback system of the present application includes an external terminal 100 with a virtual system and a robot system 200; the robot system 200 includes a handle 210, a magnetically conductive fixed platform 220, and an electrical system 230. An electromagnet 212 is arranged on the handle 210. The handle 210 contacts the magnetically conductive fixed platform 220 through the electromagnet 212 and forms a magnetic circuit. The electrical system includes an adjustable power supply 232, and the adjustable power supply 232 is used to adjust the input current of the electromagnet 212 to realize the dynamic change of the output magnetic force of the electromagnet 212, and further realize the dynamic change of the friction force between the electromagnet 212 and the magnetically conductive fixed platform 220. The present application adjusts the passive force (output force) feedback by means of magnetic attraction braking, avoiding the impact risk of the motor drive mode of the active rehabilitation robot and ensuring the safety of the training process. The tactile force feedback system and the 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, real-time collecting the user's motion intention and motion position data, and transmitting them 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 requirements of force feedback training, and adjusts the output current of the adjustable power supply 232 through the controller 231 of the electrical system 230, so as to dynamically adjust the output magnetic force of the electromagnet 212 and realize 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 goal, making the output force more accurate. At the same time, the PID control algorithm can compensate for interference and improve the dynamic response performance of the force feedback, ensuring the training effect in different rehabilitation stages. In addition, the present application designs multiple task-oriented force feedback models in the virtual environment, such as a friction force model, a virtual wall model, and a virtual rigid body model, etc., to simulate different training scenarios. Through the task design in the virtual environment, such as simulating tasks in daily life (mopping the floor, pushing a box, etc.), dynamically mapping the user's actual motion position and the virtual display position, and real-time adjusting the feedback resistance to simulate different physical properties, such as friction force, virtual wall, etc., so as to achieve the effect of enhancing the realism of the rehabilitation training.

[0068] The present application also provides a terminal device. Exemplarily, the terminal device includes a processor and a memory. Among them, the memory stores a computer program, and the processor executes the above force feedback adjustment method by running the computer program.

[0069] Among them, 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, and discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc., and can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application.

[0070] The memory can be, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), etc. Among them, the memory is used to store the computer program, and after receiving the execution instruction, the processor can execute the computer program accordingly.

[0071] The present application also provides a computer-readable storage medium for storing the computer program used in the above terminal device. For example, the computer-readable storage medium can include, but is not limited to: various media such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc that can store program codes.

[0072] In several embodiments provided by 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 illustrative. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architectures, functions, and operations of devices, methods, and computer program products according to multiple embodiments of this application. In this regard, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code, and the module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the blocks can occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the structure diagram and / or flowchart, as well as the combination of blocks in the structure diagram and / or flowchart, can be implemented by a dedicated hardware-based system that executes the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0073] In addition, in each embodiment of this application, the various functional modules or units can be integrated together to form an independent part, or each module can exist alone, or two or more modules can be integrated to form an independent part.

[0074] If the above-mentioned functions are implemented in the form of software functional 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 this application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of this application.

[0075] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application.

Claims

1. A tactile force feedback system, characterized in that, Comprising: 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 arranged 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; The electrical system is connected to the handle for real-time acquisition of the position information of the handle on the magnetic fixed platform; The external terminal is connected to the electrical system for determining control information based on the position information and the user-applied force information, and sending 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 making the output force match the motion intention.

2. The haptic force feedback system according to claim 1, wherein The handle includes a force sensor, an electromagnet, and an armrest portion; 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 portion of the magnetic fixed platform to form the output force.

3. The haptic 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 the position information of the handle on the magnetic fixed platform; The controller is used 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 indicate that the virtual object in the virtual system built in the external terminal is synchronized with the position of the handle; The controller is further used to adjust the adjustable power supply according to the received control information to adjust the magnetic force of the electromagnet.

4. A force feedback adjustment method, characterized in that, An external terminal applied to the tactile force feedback system according to any one of claims 1-3, wherein a preset training task is included in the virtual system of the external terminal, and the force feedback adjustment method includes: Determining the motion intention of the user when performing the training task according to the applied force information applied by the user to 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 by the electrical system for indicating the output magnetic force of the handle, so that the output force matches the motion intention.

5. The force feedback adjustment method according to claim 4, 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 determining the motion intention of the user when performing the training task according to the applied force information applied by the user to the handle includes: Determining the motion intention of the user when performing the training task according to the applied force applied by the user to the armrest portion of the handle and the direction of the applied force; wherein, the motion intention includes forward, backward, turning, and stopping.

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

7. The force feedback adjustment method according to claim 4, wherein The output force is determined according to the friction factor between the handle and the magnetically conductive fixed platform, the vertical force applied by the user on the magnetically conductive fixed platform through the handle, the gravity of the handle, and the output magnetic force of the electromagnet in the handle.

8. The force feedback adjustment method according to claim 7, wherein After generating the control information based on the motion intention and the position information of the handle on the magnetically conductive fixed platform, it further includes: Determine the adjustment amount of the current output current of the adjustable power supply according to the difference between the output force and the desired output force; Update the control information according to the adjustment amount to generate new control information, and send 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, and further adjusts the output magnetic force of the handle; Determine a new output force according to the adjusted output magnetic force, the vertical force applied by the handle on the magnetically conductive fixed platform, and the gravity of the handle, until the difference between the output force and the desired output force is within a preset difference range.

9. The force feedback adjustment method according to claim 8, wherein The determining the adjustment amount of the current output current of the adjustable power supply according to the difference between the output force and the desired output force includes: Based on the difference between the output force and the desired output force, combine the proportional-integral-derivative control algorithm to determine the adjustment amount of the current output current of the adjustable power supply; Wherein, the calculation formula of the adjustment amount is: wherein, is the proportional gain; is the integral gain; is the derivative gain; u is the adjustment amount; e is the difference between the output force and the desired output force.

10. A force feedback adjustment method, characterized in that, Applied to an external terminal and a robot system in the haptic force feedback system according to any one of claims 1-3, the virtual system of the external terminal includes a preset training task, and the force feedback adjustment method includes: The robot system sends the applied force information applied by the user on the handle and the position information of the handle on the magnetically conductive fixed platform to the external terminal; The external terminal determines the motion intention of the user when performing the training task according to the applied force information, and generates control information based on the motion intention and the position information of the handle on the magnetically conductive fixed platform; Wherein, 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 motion intention.

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