A force feedback device and method for muscle tone assessment

Abstract

This invention provides a force feedback device and method for muscle tension assessment. The device includes a support mechanism, a stiffness adjustment mechanism, a torque output mechanism, an electro-adsorption device, a sensor unit, a control processing unit, and a power module. Force sensing in the force feedback device is achieved using an elastic element. A specially designed variable stiffness mechanism can change the effective lever arm length between the elastic element and the output point, thereby achieving controllable stiffness. The feedback force can be calculated by measuring the deformation of the elastic element under load. The stiffness felt by the user during trigger pressing is controllable, providing higher quality stiffness and force feedback. Furthermore, the characteristics of the spring also enhance the safety of the force feedback device. The on / off state of the designed electro-adsorption device controls the switching on and off of the device's force feedback interaction function.

Description

Technical Field

[0001] This invention belongs to the field of mechanical and sensor technology, and relates to a force feedback device and method for muscle tone assessment. Background Technology

[0002] Muscle tone refers to the resistance exhibited by muscles during passive stretching, and is an important indicator of the functional state of the nervous system and hemiplegic status. Muscle tone is usually reflected by stiffness. Traditional muscle tone assessment generally uses palpation methods, which mainly rely on the doctor's feel and experience, and has a certain degree of subjectivity and uncertainty, making it difficult to quantify and standardize.

[0003] Telemedicine, as an important component of modern medical technology, is gradually becoming a crucial means to address the uneven distribution of medical resources and improve the efficiency of medical services. However, in a telemedicine environment, the physical distance between doctors and patients prevents the direct application of remote palpation methods, which limits the accuracy and comprehensiveness of telemedicine diagnoses.

[0004] The development of force feedback technology has opened up new possibilities for remote palpation. Through force feedback devices, doctors can obtain tactile feedback similar to direct palpation during remote operations, thereby improving the accuracy and reliability of remote diagnosis. Currently, some force feedback devices are being used in the field of telemedicine, but certain challenges remain in structural design and use, such as insufficient accuracy, low safety, inconvenience in use, and compatibility issues with other telemedicine systems. Summary of the Invention

[0005] To address the problems of existing technologies, this invention designs a force feedback device and method for muscle tone assessment. The force feedback device uses an elastic element for force sensing, and a specially designed variable stiffness mechanism can change the effective lever arm length between the elastic element and the output point, thereby achieving controllable stiffness of the device. The feedback force can be calculated by measuring the deformation of the elastic element under load. Furthermore, a designed electro-adsorption device allows for the selection of whether force feedback interaction is activated. It is important to note that in this force feedback device, the motor only changes the position of the elastic element's application point and provides the necessary horizontal balancing force; it does not directly participate in the output of the feedback force. Therefore, this device is a quasi-passive force feedback device.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A force feedback device for muscle tension assessment includes a support mechanism, a stiffness adjustment mechanism, a torque output mechanism, an electro-adsorption device, a sensor unit, a control processing unit, and a power module. The support mechanism includes a grip and a base connected to the grip. The stiffness adjustment mechanism includes a stiffness motor mounted on the base and a slider seat connected to the output shaft of the stiffness motor, with an elastic element fixed on the slider seat. The torque output structure is mounted on the upper end of the stiffness adjustment mechanism and slidably connected to it. Its two ends are mounted inside the support mechanism via bearings. The torque output structure includes components that contact the stiffness adjustment mechanism. The compression rod, when pressed on one side, exerts pressure on the elastic element of the stiffness adjustment mechanism. The reaction force generated by the compression of the elastic element acts on the finger, thus sensing the torque. The electro-adsorption device, connected to the torque output structure, includes an electro-adsorption anode and an electro-adsorption cathode. The on / off state of the power supply controls the adsorption of the cathode and anode, thereby opening and closing the force sensor interaction. The sensor unit is used to detect and calculate the compression amount of the elastic element. The stiffness adjustment mechanism, sensor unit, and control processing unit are all connected to the power module.

[0008] Furthermore, the support mechanism includes a base, a base connector, a handle, a handle connector, an encoder receiving component, a position pulley, and a deflection angle pulley; the base connector is U-shaped, with its bottom fixed below the L-shaped base; the handle connector and the encoder receiving component are respectively fixedly installed at the front and rear ends of the base connector, the handle is fixedly connected to the handle connector, the two encoders are respectively fixed on the left and right sides of the encoder receiving component, and the position pulley and the deflection angle pulley are coaxially engaged with the output shafts of the two encoders.

[0009] Furthermore, the stiffness adjustment mechanism includes a stiffness motor, a stiffness guide rail, a stiffness slider, a stiffness slider stopper, a slider seat, a left spring, a right spring, a front balance block, a rear balance block, an upper spring fixing member, a lower spring fixing member, a spring block, a front bearing screw, and a rear bearing screw. The stiffness motor is installed at the tail of the base, the stiffness guide rail is fixedly installed on the upper part of the base, and the stiffness slider is installed in conjunction with the stiffness guide rail and can move along the direction of the stiffness guide rail. The stiffness slider stopper is fixed at the front of the base to prevent the stiffness slider from falling off. The slider seat is fixedly installed on the upper part of the stiffness slider, and its tail is fixedly connected to the front and rear balance blocks. The slider seat is also connected to the output shaft of the stiffness motor. The left and right springs are arranged between the upper and lower spring fixing members. The lower spring fixing member is fixed on the upper part of the slider seat, and the upper spring fixing member is fixed on the bottom of the spring block. The front bearing screw and the rear bearing screw are respectively installed on both sides of the spring block.

[0010] Furthermore, the front bearing screw and the rear bearing screw are installed at the center positions of the front and rear sides of the spring block.

[0011] Furthermore, the upper spring fixing member and the lower spring fixing member are respectively provided with through holes for constraining the spring.

[0012] Furthermore, the torque output mechanism includes a torque guide rail, a torque slider, a front compression rod, a rear compression rod, a front fixed rod, a rear fixed rod, a support frame, a trigger, a trigger shaft, a base pulley, and a compression rod pulley. The torque guide rail is connected to the slider seat, and the direction of the torque guide rail is perpendicular to the direction of the stiffness guide rail. The torque slider is fitted with the torque guide rail and can move along the direction of the torque guide rail. The torque slider is fixedly connected to the spring block. The output shaft of the front compression rod is connected to the base connector and the front fixed rod through bearings, and the output shaft of the rear compression rod is connected to the base connector and the rear fixed rod through bearings. The support frame is fixed inside the front and rear fixed rods. The trigger shaft is fixed between the front and rear fixed rods, and the trigger and one end of the trigger shaft are connected through bearings. The base pulley and the compression rod pulley are driven by a PU belt in conjunction with a position pulley and a deflection angle pulley, respectively.

[0013] Furthermore, the electro-adsorption device includes an electro-adsorption frame, a front swing rod, a rear swing rod, an electro-adsorption base, an electro-adsorption top cover, an electro-adsorption anode, an electro-adsorption cathode, and an electro-adsorption shaft; the lower two sides of the electro-adsorption frame are fixedly connected to the front and rear compression rods respectively, and the upper two sides are connected to the front and rear swing rods respectively through bearings; the two ends of the electro-adsorption base are fixed to the electro-adsorption cathode, and one end is also fixedly connected to the electro-adsorption shaft; the electro-adsorption anode is disposed between the electro-adsorption base and the electro-adsorption cathode, and its two ends are fixed to the electro-adsorption top cover and the front and rear swing rods respectively; the two ends of the electro-adsorption shaft are respectively installed between the front and rear fixed rods through bearings.

[0014] Furthermore, the sensor unit includes a stiffness motor encoder, a position encoder, and a deflection angle encoder. The stiffness motor encoder is integrated at the end of the stiffness motor and is used to collect the output shaft length information of the motor. The position encoder and the deflection angle encoder are installed on the left and right sides of the encoder support. The output shaft of the position encoder is fixed to the position pulley and is used to measure the real-time angle of the index finger pressing through PU belt drive. The output shaft of the deflection angle encoder is fixed to the deflection angle pulley and is used to measure and calculate the compression angle of the spring through PU belt drive.

[0015] A force feedback method for muscle tone assessment, based on a force feedback device for muscle tone assessment, includes the following steps:

[0016] When the electro-adsorption device is powered on, the electro-adsorption anode and the electro-adsorption cathode adsorb tightly.

[0017] The pressure is transmitted through the front and rear compression rods to the front and rear bearing screws, causing the left and right springs to deform and generate a reaction force, thus forming force feedback.

[0018] The characteristic stiffness and feedback torque of the force feedback device are obtained through the encoder unit and the control processing unit.

[0019] When it is necessary to adjust the characterization stiffness, the stiffness motor is controlled to move, so that the contact points of the front bearing screw and the rear bearing screw on the front compression rod and the rear compression rod change.

[0020] Furthermore, the stiffness δ and feedback torque τ of the force feedback device... o Calculated using the following formula:

[0021]

[0022] Where k is the spring stiffness coefficient, θ τ The compression angle of the index finger pressing mechanism is obtained through the deflection angle encoder. sd This is the equivalent length between the spring block and the rotation center obtained through the stiffness motor encoder.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] This invention controls the on / off state of the force feedback function of a device by switching the electro-adsorption device on and off. When the electro-adsorption device is in the on / off state, it acts as a fixed whole. When the index finger presses the trigger, the spring deforms and provides a feedback reaction force, thus creating force feedback. The magnitude of the force feedback depends not only on the pressure of the index finger but also on the characteristic stiffness of the device. This invention utilizes the linear motion of a stiffness motor to control the effective lever arm length between the spring and the fulcrum, thereby controlling the characteristic stiffness of the force feedback device. This makes the device stiffness felt by the user during trigger pressing controllable, providing higher quality stiffness and force feedback. Simultaneously, the characteristics of the spring also enhance the safety of the force feedback device. The stiffness motor of this invention is only used to adjust the characteristic stiffness and provide the necessary horizontal balancing force; it does not directly participate in the output of the feedback force. Therefore, this device is a quasi-passive force feedback device. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the electrical connections of the components of the force feedback device for muscle tone assessment provided by the present invention;

[0026] Figure 2 This is a perspective view of the force feedback device for muscle tone assessment provided by the present invention;

[0027] Figure 3 This is a front view of the force feedback device for muscle tone assessment provided by the present invention.

[0028] Figure 4 It is a three-dimensional view of the supporting structure;

[0029] Figure 5 This is a top view of the supporting structure;

[0030] Figure 6 This is a three-dimensional view of the stiffness adjustment mechanism;

[0031] Figure 7 This is the main view of the stiffness adjustment mechanism;

[0032] Figure 8 This is a three-dimensional view of the torque output mechanism;

[0033] Figure 9 This is the front view of the torque output mechanism;

[0034] Figure 10 This is a three-dimensional view of the electro-adsorption device;

[0035] Figure 11 This is an exploded view of the electroadsorption device.

[0036] Figure 12 It is a model diagram of the elastic element, fulcrum, and lever in a force feedback device.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Support Mechanism; 1-1. Base; 1-2. Base Connector; 1-3. Handle; 1-4. Handle Connector; 1-5. Encoder Receiving Part; 1-6. Position Pulley; 1-7. Deflection Angle Pulley; 2. Stiffness Adjustment Mechanism; 2-1. Stiffness Motor; 2-2. Stiffness Guide Rail; 2-3. Stiffness Slider; 2-4. Stiffness Slider Block; 2-5. Slider Seat; 2-6. Left Spring; 2-7. Right Spring; 2-8. Front Balance Block; 2-9. Rear Balance Block; 2-10. Upper Spring Fixing Part; 2-11. Lower Spring Fixing Part; 2-12. Spring Block; 2-13. Front Bearing Screw; 3. Torque Output Mechanism; 3-1. Torque Guide Rail; 3 -2. Torque slider; 3-3. Front compression rod; 3-4. Rear compression rod; 3-5. Front fixing rod; 3-6. Rear fixing rod; 3-7. Support frame; 3-8. Trigger; 3-9. Trigger shaft; 3-10. Base pulley; 3-11. Compression rod pulley; 4. Electro-adsorption device; 4-1. Electro-adsorption frame; 4-2. Front swing arm; 4-3. Rear swing arm; 4-4. Electro-adsorption seat; 4-5. Electro-adsorption top cover; 4-6. Electro-adsorption anode; 4-7. Electro-adsorption cathode; 4-8. Electro-adsorption shaft; 5. Sensor unit; 5-1. Stiffness motor encoder; 5-2. Position encoder; 5-3. Deflection angle encoder; 6. Control processing unit; 7. Power module. Detailed Implementation

[0039] The technical solutions provided by the present invention will be described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0040] Reference Figure 1 , Figure 2 , Figure 3 This invention provides a force feedback device for muscle tone assessment, comprising a support mechanism 1, a stiffness adjustment mechanism 2, a torque output mechanism 3, an electro-adsorption device 4, a sensor unit 5, a control processing unit 6, and a power module 7. The support mechanism 1 includes a handle (grip) and a base, serving as the frame and support for the force feedback device. The stiffness adjustment mechanism 2 is mounted on the upper part of the support mechanism 1, adjusting the stiffness of the force feedback device by adjusting the contact position of the elastic element. The torque output mechanism 3 is located above the stiffness adjustment mechanism 2 and is slidably connected to it. Its two ends are mounted inside the support mechanism 1 via bearings. The torque output structure includes a compression rod that contacts the stiffness adjustment mechanism 2. When one side of the compression rod is pressed, the pressing force acts on the elastic element of the stiffness adjustment mechanism 2, and the reaction force generated by the compression of the elastic element acts on the finger, thus achieving torque sensing. The electro-adsorption device 4 is positioned above and connected to the torque output structure 3. The power supply to the electro-adsorption device 4 can be switched on or off to activate the force feedback interaction of the device. Sensor unit 5 detects information about the stiffness motor, spring deflection angle, and index finger pressing position, and is used for detecting and calculating the compression of the elastic element. Sensor unit 5 is connected to control processing unit 6 (with data and signal connection). Control processing unit 6 is used for data processing of sensor unit and control of stiffness motor, and power module 7 supplies power to various mechanisms, units, and modules of the force feedback device.

[0041] Reference Figure 4 , Figure 5Specifically, the support mechanism 1 includes a base 1-1, a base connector 1-2, a handle 1-3, a handle connector 1-4, an encoder receiver 1-5, a position pulley 1-6, and a deflection angle pulley 1-7. The base 1-1 has an L-shaped design, and the base connector 1-2 has a U-shaped design. The interior of the U-shaped component (specifically, the inner bottom side) is fixed to the base 1-1 via four positioning holes and fasteners. The bottom of the U-shaped component is located below the base 1-1. The two sides of the U-shaped component are fixed to the handle connector 1-4 and the encoder receiver 1-5 respectively via threaded holes and fasteners. The handle 1-3 is fixed to the handle connector 1-4 with screws. The position encoder 5-2 and the deflection angle encoder 5-3 are respectively installed and fixed on the left and right sides of the encoder connector 1-5. The position pulley 1-6 and the deflection angle pulley 1-7 are respectively installed on the output shafts of the position encoder 5-2 and the deflection angle encoder 5-3 in a staggered manner, and are separated from the position encoder 5-2 and the deflection angle encoder 5-3 by the encoder connector 1-5.

[0042] Reference Figure 2 , Figure 3 , Figure 6 , Figure 7 The stiffness adjustment mechanism 2 includes a stiffness motor 2-1, a stiffness guide rail 2-2, a stiffness slider 2-3, a stiffness slider stopper 2-4, a slider seat 2-5, a left spring 2-6, a right spring 2-7, a front balance block 2-8, a rear balance block 2-9, an upper spring fixing part 2-10, a lower spring fixing part 2-11, a spring block 2-12, a front bearing screw 2-13, and a rear bearing screw. The stiffness motor 2-1 is mounted on the tail of the base 1-1 via a positioning hole and a pin. The stiffness guide rail 2-2 and the stiffness slider stopper 2-4 are mounted on the upper and front parts of the base 1-1 respectively via threaded holes. The stiffness slider 2-3 is mounted on the stiffness guide rail 2-2 and slides in cooperation. The stiffness slider stopper 2-4 is used to prevent the stiffness slider from falling off. The slider seat 2-5 is L-shaped and its bottom is mounted on the rigidity slider 2-3. A fixing hole is provided at the rear of the slider seat 2-5, and its vertical part is fixed to the output shaft of the rigidity motor 2-1 by a pin. The upper spring fixing part 2-10 and the lower spring fixing part 2-11 are respectively located above and below the left spring 2-6 and the right spring 2-7. They each have two circular through holes to constrain the left spring 2-6 and the right spring 2-7, with both ends of the left spring 2-6 and the right spring 2-7 slightly extending into the circular through holes. The upper spring fixing part 2-10 and the lower spring fixing part 2-11 are fixed to the upper part of the slider seat 2-5 and the bottom of the spring block 2-12 by four threaded holes. The front balance block 2-8 and the rear balance block 2-9 are respectively installed on the front and rear sides of the slider seat 2-5. The front bearing screw 2-13 and the rear bearing screw are respectively installed at the center positions of the front and rear sides of the spring block 2-12. Due to the perspective, the rear bearing screw is not shown in the figure. It has the same shape as the front bearing screw 2-1, but is positioned opposite to it.

[0043] Reference Figure 2 , Figure 3 , Figure 8 , Figure 9 The torque output mechanism 3 includes a torque guide rail 3-1, a torque slider 3-2, a front compression rod 3-3, a rear compression rod 3-4, a front fixed rod 3-5, a rear fixed rod 3-6, a support frame 3-7, a trigger 3-8, a trigger shaft 3-9, a base pulley 3-10, and a compression rod pulley 3-11. The torque guide rail 3-1 is installed inside the slider seat 2-5, and the torque slider 3-2 is installed on the torque guide rail 3-1 and slides in cooperation. The torque slider 3-2 is fixedly installed to the spring block 2-12 through a threaded hole. Both the front compression rod 3-3 and the rear compression rod 3-4 have output shafts on their sides. The front compression rod 3-3 is installed with the base connector 1-2 and the front fixed rod 3-5 through bearings and can rotate relative to each other. The ends of the output shafts of the front fixed rod 3-5 and the front compression rod 3-3 are respectively fixed to the staggered base pulley 3-10 and compression rod pulley 3-11 by screws. The rear compression rod 3-4 is mounted to the base connector 1-2 and the rear fixing rod 3-6 via bearings and can rotate relative to each other. The support frame 3-7 has an I-beam design, with both ends fixedly mounted between the front fixing rod 3-5 and the rear fixing rod 3-6, respectively, for support and spacing control. The trigger shaft 3-9 is fixed at both ends to the inner sides of the front fixing rod 3-5 and the rear fixing rod 3-6, with one end extending from the rear fixing rod 3-6 and mounted to the trigger 3-8 via a bearing. The trigger 3-8 and the trigger shaft 3-9 can rotate relative to each other. The base pulley 3-10 and the compression rod pulley 3-11 are connected to the position pulley 1-6 and the deflection angle pulley 1-7 via PU belts for transmission.

[0044] Reference Figure 2 , Figure 3 , Figure 10 , Figure 11The electro-adsorption device 4 includes an electro-adsorption frame 4-1, a front swing rod 4-2, a rear swing rod 4-3, an electro-adsorption base 4-4, an electro-adsorption top cover 4-5, an electro-adsorption anode 4-6, an electro-adsorption cathode 4-7, and an electro-adsorption shaft 4-8. The electro-adsorption frame 4-1 has a U-shaped design. The lower ends of the U-shape are fixed to the inner sides of the front compression rod 3-3 and the rear compression rod 3-4 by screws, while the upper ends of the U-shape are respectively installed with bearings to the output shafts of the front swing rod 4-2 and the rear swing rod 4-3. The electro-adsorption base 4-4 has symmetrical threaded holes at both ends for fixing the electro-adsorption cathode 4-7. The electro-adsorption top cover 4-5 also has symmetrical threaded holes at both ends. The electro-adsorption anode 4-6 is located between the electro-adsorption base 4-4 and the electro-adsorption cathode 4-7, with its upper ends fixed to the electro-adsorption top cover 4-5 and its lower ends fixed to the front swing rod 4-2 and the rear swing rod 4-3 through threaded holes. The two ends of the electro-adsorption shaft 4-8 are mounted between the front fixed shaft 3-5 and the rear fixed shaft 3-6 via bearings, and one end is fixed to the electro-adsorption seat 4-4 via threaded holes and fasteners.

[0045] Sensor unit 5 includes a stiffness motor encoder 5-1, a position encoder 5-2, and a deflection angle encoder 5-3, such as... Figure 6 , Figure 7 As shown, the stiffness motor encoder 5-1 is integrated at the end of the stiffness motor 2-1, and is used to collect the output shaft length information of the motor to determine the stiffness of the system. Figure 5 As shown, the position encoder 5-2 and the deflection encoder 5-3 are mounted on the left and right sides of the encoder receiver 1-5, respectively, and are driven by relevant pulleys and PU belts to collect real-time angle information of index finger pressing and spring compression. Specifically, the output shaft of the position encoder is fixed to the position pulley and is driven by the PU belt to measure the real-time angle of index finger pressing. The output shaft of the deflection encoder is fixed to the deflection pulley and is driven by the PU belt to measure and calculate the spring compression angle. The stiffness and output torque of the force feedback device can be calculated using the return values ​​of the stiffness motor encoder and the deflection encoder.

[0046] The control processing unit 6 consists of a data acquisition and storage unit and a control processor. The data acquisition and storage unit completes the acquisition of information such as the position and speed of the sensor unit 5, and the control processor completes the processing of the acquired data and the drive control functions of the stiffness motor 2-1 and the electro-adsorption device 4.

[0047] Power module 7 provides energy to electro-adsorption device 4, sensor unit 5, control processing unit 6, and stiffness motor 2-1.

[0048] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 Based on the aforementioned force feedback device for muscle tone assessment, this invention also provides a force feedback method for muscle tone assessment. The switching on and off of the designed electro-adsorption device 4 can control the on / off state of the device's force feedback interaction function. When the electro-adsorption device 4 is in the open state, the electro-adsorption anode 4-6 and electro-adsorption cathode 4-7 are tightly adsorbed, making the electro-adsorption device 4 a fixed unit. The pressure from the user's index finger pressing the trigger 3-8 is transmitted via the electro-adsorption frame 4-1, the front compression rod 3-3, and the rear compression rod 3-4 to the front bearing screw 2-13 and the rear bearing screw 2-14, further deforming the left spring 2-6 and the right spring 2-7 and generating a reaction force, thus forming a force feedback effect. On the other hand, the linear motion of the output shaft of the stiffness motor 2-1 causes changes in the contact points of the front bearing screw 2-13 and the rear bearing screw 2-14 on the front compression rod 3-3 and the rear compression rod 3-4, respectively. This results in a change in the effective lever arm length between the spring and the fulcrum (i.e., the aforementioned contact point), thereby changing the characteristic stiffness of the force feedback device. Therefore, the characteristic stiffness of the device can be effectively controlled by controlling the position of the stiffness motor 2-1. The encoder unit 5 and the control processing unit 6 can detect and calculate the real-time stiffness and the pressure applied by the user's index finger, and can adjust the stiffness in real time according to different usage scenarios and pressure sensitivity, providing users with higher quality stiffness and force feedback. At the same time, the characteristics of the spring also make the force feedback device of this invention safer. On the other hand, the motor used in this invention is only used to adjust the characteristic stiffness and provide the necessary horizontal balancing force, and does not directly participate in the output of the feedback force. Therefore, this device is a quasi-passive force feedback device.

[0049] The feedback torque and characterizing stiffness of the force feedback device can be calculated from the return values ​​of the stiffness motor encoder and the deflection angle encoder. Figure 12 This is a basic model for the elastic element, fulcrum, and lever in a force feedback device. For ease of representation, the following geometric parameters need to be defined first:

[0050] (1) The spring stiffness coefficient is k, therefore the stiffness coefficient of the spring block is 2k;

[0051] (2) The equivalent length between the spring block and the rotation center can be obtained by calculation using a stiffness motor encoder. sd ;

[0052] (3) The compression angle θ of the index finger pressing press can be obtained by deflection angle encoder. τ ;

[0053] Based on the above parameters, the deformation l of the spring caused by the pressure of the index finger is... cfor:

[0054] l c =l sd tanθ τ

[0055] At this moment, the spring's reaction force F s for

[0056] F s =2kl c =2kl sd tanθ τ

[0057] Since the contact point between the compression rod and the bearing screw is not directly above the bearing screw at this time, the force F between them is also subject to the constraint force F of the stiffness guide rail. b The impact, namely:

[0058]

[0059] At this time, the lever arm length corresponding to F is l. F =l sd / cosθ τ Since stiffness is the partial derivative of torque with respect to rotation angle, the feedback torque τ of the spring block can be obtained. o And the expression characterizing stiffness δ, namely:

[0060]

[0061] In summary, the stiffness represented by the force feedback device depends on the output shaft position of the stiffness motor. Both the force feedback and the represented stiffness felt by the user's index finger can be calculated from the return values ​​of the stiffness motor encoder and the deflection angle encoder. Therefore, in telemedicine scenarios, doctors can obtain force and stiffness feedback similar to direct palpation during remote operation using the force feedback device provided by this invention. Furthermore, the patient's muscle stiffness information can be measured and recorded, providing data support for doctors' quantitative assessment of patient muscle tension.

[0062] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A force feedback device for muscle tone assessment, characterized in that, include: The system comprises a support mechanism, a stiffness adjustment mechanism, a torque output mechanism, an electro-adsorption device, a sensor unit, a control processing unit, and a power module. The support mechanism includes a handle and a base connected to the handle. The stiffness adjustment mechanism includes a stiffness motor mounted on the base and a slider seat connected to the output shaft of the stiffness motor, with an elastic element fixed on the slider seat. The torque output structure is mounted on the upper end of the stiffness adjustment mechanism and slidably connected to it. Its two ends are mounted inside the support mechanism via bearings. The torque output structure includes a compression rod in contact with the stiffness adjustment mechanism; when one side of the compression rod is pressed, the pressing force acts on the elastic element of the stiffness adjustment mechanism. The elastic element, due to compression, generates a reaction force that acts on the finger, thus enabling torque sensing. The stiffness adjustment mechanism is installed on the upper part of the support mechanism, and adjusts the stiffness of the force feedback device by adjusting the contact position between the compression rod and the elastic element. The electro-adsorption device is connected to the torque output structure and includes an electro-adsorption anode and an electro-adsorption cathode. The on / off state of the power supply controls the adsorption of the cathode and anode, thereby opening and closing the force sensing interaction. The sensor unit is used for detecting and calculating the compression amount of the elastic element. The stiffness adjustment mechanism, the sensor unit, and the control processing unit are all connected to the power module.

2. The force feedback device for muscle tone assessment according to claim 1, characterized in that, The support mechanism includes a base, a base connector, a handle, a handle connector, an encoder receiver, a position pulley, and a deflection angle pulley. The base connector is U-shaped, with its bottom fixed below the L-shaped base. The handle connector and the encoder receiver are respectively fixedly installed at the front and rear ends of the base connector. The handle is fixedly connected to the handle connector. The two encoders are respectively fixed on the left and right sides of the encoder receiver. The position pulley and the deflection angle pulley are coaxially engaged with the output shafts of the two encoders.

3. The force feedback device for muscle tone assessment according to claim 1, characterized in that, The stiffness adjustment mechanism includes a stiffness motor, a stiffness guide rail, a stiffness slider, a stiffness slider stopper, a slider seat, a left spring, a right spring, a front balance block, a rear balance block, an upper spring fixing member, a lower spring fixing member, a spring block, a front bearing screw, and a rear bearing screw. The stiffness motor is installed at the tail of the base, the stiffness guide rail is fixedly installed on the upper part of the base, and the stiffness slider is installed in conjunction with the stiffness guide rail and can move along the direction of the stiffness guide rail. The stiffness slider stopper is fixed at the front of the base to prevent the stiffness slider from falling off. The slider seat is fixedly installed on the upper part of the stiffness slider, and its tail is fixedly connected to the front and rear balance blocks. The slider seat is also connected to the output shaft of the stiffness motor. The left and right springs are arranged between the upper and lower spring fixing members. The lower spring fixing member is fixed on the upper part of the slider seat, and the upper spring fixing member is fixed on the bottom of the spring block. The front bearing screw and the rear bearing screw are respectively installed on both sides of the spring block.

4. The force feedback device for muscle tone assessment according to claim 3, characterized in that, The front bearing screw and the rear bearing screw are installed at the center positions of the front and rear sides of the spring block.

5. The force feedback device for muscle tone assessment according to claim 3, characterized in that, The upper spring fixing member and the lower spring fixing member are respectively provided with through holes for constraining the spring.

6. The force feedback device for muscle tone assessment according to claim 3, characterized in that, The torque output mechanism includes a torque guide rail, a torque slider, a front compression rod, a rear compression rod, a front fixed rod, a rear fixed rod, a support frame, a trigger, a trigger shaft, a base pulley, and a compression rod pulley. The torque guide rail is connected to the slider seat, and the direction of the torque guide rail is perpendicular to the direction of the stiffness guide rail. The torque slider is installed in conjunction with the torque guide rail and can move along the direction of the torque guide rail. The torque slider is fixedly connected to the spring block. The output shaft of the front compression rod is connected to the base connector and the front fixed rod through bearings, and the output shaft of the rear compression rod is also connected to the base connector and the rear fixed rod through bearings. The support frame is fixed inside the front and rear fixed rods. The trigger shaft is fixed between the front and rear fixed rods, and the trigger and one end of the trigger shaft are connected through bearings. The base pulley and the compression rod pulley are driven by a PU belt in conjunction with a position pulley and a deflection angle pulley, respectively.

7. The force feedback device for muscle tone assessment according to claim 6, characterized in that, The electro-adsorption device includes an electro-adsorption frame, a front swing rod, a rear swing rod, an electro-adsorption base, an electro-adsorption top cover, an electro-adsorption anode, an electro-adsorption cathode, and an electro-adsorption shaft. The lower two sides of the electro-adsorption frame are fixedly connected to the front and rear compression rods respectively, and the upper two sides are connected to the front and rear swing rods respectively through bearings. The two ends of the electro-adsorption base are fixed to the electro-adsorption cathode, and one end is also fixedly connected to the electro-adsorption shaft. The electro-adsorption anode is disposed between the electro-adsorption base and the electro-adsorption cathode, and its two ends are fixed to the electro-adsorption top cover and the front and rear swing rods respectively. The two ends of the electro-adsorption shaft are respectively installed between the front and rear fixed rods through bearings.

8. The force feedback device for muscle tone assessment according to claim 1, characterized in that, The sensor unit includes a stiffness motor encoder, a position encoder, and a deflection angle encoder. The stiffness motor encoder is integrated at the end of the stiffness motor and is used to collect the output shaft length information of the motor. The position encoder and the deflection angle encoder are installed on the left and right sides of the encoder support. The output shaft of the position encoder is fixed to the position pulley and is used to measure the real-time angle of the index finger pressing through PU belt drive. The output shaft of the deflection angle encoder is fixed to the deflection angle pulley and is used to measure and calculate the compression angle of the spring through PU belt drive.

9. A force feedback method for muscle tone assessment, characterized in that, Based on the force feedback device for muscle tone assessment according to any one of claims 1-8, the method comprises the following steps: When the electro-adsorption device is powered on, the electro-adsorption anode and the electro-adsorption cathode adsorb tightly. The pressure is transmitted through the front and rear compression rods to the front and rear bearing screws, causing the left and right springs to deform and generate a reaction force, thus forming force feedback. The encoder unit and control processing unit acquire real-time stiffness, pressing force, and real-time angle of spring compression. When it is necessary to adjust the stiffness, the stiffness motor is controlled to change the contact points of the front bearing screw and the rear bearing screw on the front compression rod and the rear compression rod.

10. The force feedback method for muscle tone assessment according to claim 9, characterized in that, Stiffness of the force feedback device and feedback torque Calculated using the following formula: ； ； in, This is the spring stiffness coefficient. The compression angle of the index finger pressing button is obtained by the deflection angle encoder. This is the equivalent length between the spring block and the rotation center obtained through the stiffness motor encoder.

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