Forearm pronation-supination perception device and rehabilitation robot

Abstract

The application provides a forearm pronation-supination sensing device and a rehabilitation robot, and relates to the technical field of rehabilitation exercise, and aims to solve the problem that the forearm pronation-supination torque is difficult to measure.The forearm pronation-supination sensing device comprises a holding mechanism, a force sensing mechanism, a guide rail mechanism and a circuit module, the holding mechanism is connected to the force sensing mechanism, the force sensing mechanism is connected to the guide rail mechanism in a relative rotation mode, the force sensing mechanism is electrically connected to the circuit module, and the rotation axis of the force sensing mechanism relative to the guide rail mechanism is configured as the axis of forearm pronation or supination.The forearm pronation-supination torque can be conveniently measured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rehabilitation exercise, in particular to a forearm pronation and supination sensing device and a rehabilitation robot. BACKGROUND

[0002] To solve the problem of insufficient stroke rehabilitation physicians, rehabilitation robots have become a research hotspot in the field of stroke rehabilitation treatment. They can assist or even replace physicians to provide more continuous, effective and more targeted rehabilitation training and treatment for patients, alleviate the shortage of rehabilitation medical resources, and record the treatment data of patients in real time to provide objective basis for disease assessment and program improvement.

[0003] Rehabilitation training of the upper limbs is extremely crucial for patients to regain the ability of daily life, especially the coordinated operation of the elbow and forearm, which greatly expands the activity range of the hand. In the estimation of the elbow and forearm torque, the movement intention of the patient can be revealed, which is the core link of active rehabilitation training and has become the focus of medical research. Although there are many studies on elbow torque and it is widely used in the field of human-computer interaction control, the research on forearm pronation and supination joint torque is relatively less. The traditional method of measuring joint torque using torque sensors is less applied to forearm pronation and supination joints due to the large volume of torque sensors and difficulty in installation. To solve the problem of difficulty in measuring forearm pronation and supination joint torque, some institutions have proposed a method based on data modeling.

[0004] For example, CN118303873A (publication date 2024.07.09) discloses a forearm joint torque prediction method and a prediction model acquisition method and device. The method includes: acquiring forearm muscle movement data of a human forearm in a rotation process collected by a wearable device, and real-time joint torque of the human forearm in the rotation process collected by a verification device, and extracting forearm rotation movement features from the forearm muscle movement data; then, based on the forearm rotation movement features and the real-time joint torque, the model is regression trained, so as to obtain a model capable of quickly and accurately predicting the forearm joint torque. Especially for upper limb rehabilitation training and other scenes, by accurately estimating the joint torque of the forearm, it is beneficial to rehabilitation training.

[0005] The above method indirectly predicts the forearm joint torque by establishing a model of the forearm joint torque through forearm muscle movement data, which requires collecting a large amount of data, the accuracy depends on the modeling accuracy, and it is time-consuming and laborious and the accuracy cannot be guaranteed. To solve the above problems, the present application proposes a forearm pronation and supination force sensing mechanism and a rehabilitation robot. The force sensing mechanism determines the forearm pronation and supination joint torque through a force sensitive resistor sensor, achieving fast and accurate force sensing. SUMMARY

[0006] The first aspect of the present application aims to provide a forearm pronation-supination sensing device to solve the technical problem that the existing forearm pronation-supination torque is difficult to measure.

[0007] The forearm pronation-supination sensing device provided by the first aspect of the present application comprises a holding mechanism, a force sensing mechanism, a guide rail mechanism, and a circuit module, the holding mechanism is connected to the force sensing mechanism, the force sensing mechanism is connected to the guide rail mechanism in a relative rotation manner, the force sensing mechanism is electrically connected to the circuit module, and the rotation axis of the force sensing mechanism relative to the guide rail mechanism is configured as the axis of forearm pronation or supination.

[0008] The forearm pronation-supination sensing device provided by the present application has the following beneficial effects:

[0009] When the forearm of a rehabilitation person is pronated or supinated, the torque transmitted by the rehabilitation person through the holding mechanism can be directly measured by directly using the force sensing mechanism, without the need for a large-volume torque sensor, and the installation is easy. In addition, compared with the data modeling method, the measurement accuracy can be better guaranteed.

[0010] In an optional technical solution, the force sensing mechanism is fixedly installed on the restraint mechanism, and the restraint mechanism is used to apply restraint to the forearm to limit the movement of the forearm to only pronation or supination.

[0011] In an optional technical solution, the force sensing mechanism comprises a force transmission member and a base, the force transmission member is fixedly connected to the holding mechanism, the force transmission member is rotationally arranged relative to the base, a first end of the force transmission member abuts against a first force sensing piece, and a second end of the force transmission member abuts against a second force sensing piece; when the force transmission member rotates relative to the base under the action of the pronation-supination torque of the forearm, the first end and the second end respectively drive the corresponding force sensing pieces to deform, the deformation causes the output of the circuit module to change correspondingly, and the pronation-supination torque of the forearm is determined through the output of the circuit module; the first force sensing piece and the second force sensing piece are fixedly arranged relative to the base.

[0012] In an optional technical solution, the force sensing mechanism further comprises a first spring and a second spring, the first spring is located between the first end and the first force sensing piece, the second spring is located between the second end and the second force sensing piece, the first spring and the second spring are used to apply forces in the same direction to the force transmission member; and when the forearm is not pronated or supinated, the first spring and the second spring apply torques of the same size and opposite directions relative to the rotation axis of the force transmission member; the stiffness of the first spring and the second spring is configured to make the rotation angle of the force transmission member relative to the base within 5°.

[0013] In an optional technical solution, the force sensing mechanism further comprises a spring seat, the first spring and the second spring are respectively sleeved in the spring seat; the force transmission member comprises a first lug and a second lug, the first lug abuts against the first spring, and the second lug abuts against the second spring.

[0014] In an optional technical solution, the force sensing mechanism further comprises a third spring and a fourth spring, the third spring and the first spring respectively abut against the first lug from opposite sides of the first lug, and the fourth spring and the second spring respectively abut against the second lug from opposite sides of the second lug.

[0015] In an optional technical solution, the first spring and the second spring are both compression springs, and the end of the first spring and the end of the second spring are respectively provided with a gasket.

[0016] In an optional technical solution, the force sensing mechanism further comprises a first sensor seat and a second sensor seat, the first sensor seat and the second sensor seat are fixedly arranged opposite to the base, the first force sensing member is fixedly installed in the first sensor seat, and the second force sensing member is fixedly installed in the second sensor seat.

[0017] In an optional technical solution, the circuit module comprises a reference power supply, an amplifier power supply, a first operational amplifier, a first feedback resistor, a first decoupling capacitor, a second operational amplifier, a second feedback resistor, a second decoupling capacitor, and a processor; the first operational amplifier and the second operational amplifier are both grounded at the positive input end; the first feedback resistor and the first decoupling capacitor are both connected in parallel and connected between the negative input end and the output end of the first operational amplifier; the second feedback resistor and the second decoupling capacitor are both connected in parallel and connected between the negative input end and the output end of the second operational amplifier; the first force sensing member is connected between the reference power supply and the negative input end of the first operational amplifier, and the second force sensing member is connected between the reference power supply and the negative input end of the second operational amplifier; the output end of the first operational amplifier is connected to the first analog-to-digital converter of the processor, and the output end of the second operational amplifier is connected to the second analog-to-digital converter of the processor.

[0018] The second aspect of the present application aims to provide a rehabilitation robot to solve the technical problem that the forearm pronation-supination torque is difficult to measure.

[0019] The rehabilitation robot provided by the second aspect of the present application comprises the forearm pronation-supination sensing device.

[0020] By setting the forearm pronation-supination sensing device in the rehabilitation robot, the rehabilitation robot has all the advantages of the forearm pronation-supination sensing device, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background art, the drawings needed to be used in the embodiments or background art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0022] Figure 1 The structure diagram of the forearm pronation-supination sensing device provided by the first embodiment of the present application.

[0023] Figure 2 The structure diagram of the force sensing mechanism in the forearm pronation-supination sensing device provided by the first embodiment of the present application.

[0024] Figure 3 The sectional view of the force sensing mechanism in the forearm pronation-supination sensing device provided by the first embodiment of the present application.

[0025] Figure 4 The schematic diagram of the circuit module in the forearm pronation-supination sensing device provided by the first embodiment of the present application.

[0026] Figure 5 The force sensing analysis diagram of the force sensing mechanism in the forearm pronation-supination sensing device provided by the first embodiment of the present application when applied to the right forearm pronation.

[0027] Figure 6 The force sensing analysis diagram of the force sensing mechanism in the forearm pronation-supination sensing device provided by the first embodiment of the present application when applied to the right forearm supination.

[0028] Figure 7 The structure diagram of the rehabilitation robot provided by the second embodiment of the present application.

[0029] BRIEF DESCRIPTION OF DRAWINGS

[0030] 100-holding mechanism; 200-force sensing mechanism; 300-guide rail mechanism; 400-circuit module; 600-confinement mechanism;

[0031] 201-Base; 2011-First countersunk hole; 2012-Second countersunk hole; 202-Force transmission component; 2021-First lug; 2022-Second lug; 203-Spring seat; 2031-First through hole; 2032-Second through hole; 204-Cylindrical pin; 205-First sensor seat; 206-First force sensing element; 2061-First pin; 2062-Second pin; 207-First upper spring pad; 208-First spring; 209-First lower spring pad; 210-Third spring; 211-Second sensor seat; 212-Second force sensing element; 2121-Third pin; 2122-Fourth pin; 213-Second upper spring pad; 214-Second spring; 215-Second lower spring pad; 216-Fourth spring;

[0032] 401 - Reference power supply; 402 - Amplifier power supply; 403 - First operational amplifier; 404 - First feedback resistor; 405 - First decoupling capacitor; 406 - Second operational amplifier; 407 - Second feedback resistor; 408 - Second decoupling capacitor; 409 - Processor;

[0033] 501 - Shoulder adduction and external rotation joint; 502 - Shoulder flexion and extension joint; 503 - Shoulder rotation, internal rotation, and external rotation joint; 504 - Elbow flexion and extension joint; 505 - Forearm pronation and supination joint; 506 - Wrist dorsiflexion and palmar flexion joint. Detailed Implementation

[0034] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0035] Example 1:

[0036] Figure 1 This is a schematic diagram of the forearm pronation and supination sensing device provided in Embodiment 1 of this application. Figure 1 As shown, the forearm pronation and supination sensing device provided in Embodiment 1 of this application includes a gripping mechanism 100, a force sensing mechanism 200, a guide rail mechanism 300, and a circuit module 400. The gripping mechanism 100 is connected to the force sensing mechanism 200, and the force sensing mechanism 200 is rotatably connected to the guide rail mechanism 300. The force sensing mechanism 200 is electrically connected to the circuit module 400, and the rotation axis of the force sensing mechanism 200 relative to the guide rail mechanism 300 is configured as the axis of forearm pronation or supination.

[0037] When the forearm of the rehabilitation person is pronated or supinated, the torque transmitted by the rehabilitation person through holding the holding mechanism 100 can be directly measured by directly using the force sensing mechanism 200, without the need of a large torque sensor, and the force sensing mechanism 200 is easy to install, and the measurement accuracy can be ensured compared with the data modeling method.

[0038] The holding structure includes a holding handle, the holding handle is fixedly connected with the transmission member, and the holding transmission member is fixedly connected with the force transmission member 202 described below. Of course, in another implementation manner, the holding structure can adopt other shapes of the held member, such as an ellipsoid or an olive shape, as long as the shape is convenient for the operator to hold.

[0039] The guide rail mechanism 300 can include a guide rail distributed on a half circle as a whole, and the center of the half circle is located on the rotation axis of the force sensing mechanism 200 relative to the guide rail, that is, also located on the axis of the forearm pronation or supination. When the forearm is pronated or supinated, the hand generates a torque on the holding mechanism 100, the holding mechanism 100 can transmit the torque to the force sensing mechanism 200, and the force sensing mechanism 200 can detect the torque. The connection of the force sensing mechanism 200 relative to the rotation of the guide rail mechanism 300 means that the force sensing mechanism 200 can only rotate around the axis of the forearm pronation or supination, and cannot move along the axis relative to the guide rail mechanism 300, or pitch along the rotation axis of the elbow joint.

[0040] As shown in Figure 1 Optionally, the force sensing mechanism 200 is fixedly installed on the restraint mechanism 600, and the restraint mechanism 600 is used to apply restraint to the forearm to limit the movement of the forearm to only pronation or supination.

[0041] By providing the restraint mechanism 600, the excessive degrees of freedom, such as elbow joint flexion and extension, wrist joint deviation, shoulder joint compensation, and the like, can be limited, and the training action of the patient due to insufficient muscle strength or movement control disorder can be prevented from deviating.

[0042] The restraint mechanism 600 includes a flexible restraint belt fixedly connected to the base 201 described below. After the restraint belt passes through the restraint hole and is reversely folded, the arm of the rehabilitation person is tightened, and the tightening is performed by using a magic tape or a hook-and-loop fastener, so that the movement of the forearm of the rehabilitation person relative to the base 201 can be effectively inhibited, thereby preventing the movement of the remaining degrees of freedom from being generated, and preventing the force sensing mechanism 200 from being interfered with the measurement of the force.

[0043] Figure 2 A structural schematic view of the force sensing mechanism in the forearm pronation and supination sensing device provided by the embodiment one of the present application. Figure 3 A sectional view of the force sensing mechanism in the forearm pronation and supination sensing device provided by the embodiment one of the present application. As Figure 2 and Figure 3As shown, optionally, the force sensing mechanism 200 includes a force transmission component 202 and a base 201. The force transmission component 202 is fixedly connected to the gripping mechanism 100. The force transmission component 202 is rotated relative to the base 201 under the action of the forearm's pronation and supination torque. The first end of the force transmission component 202 abuts against the first force sensor 206, and the second end of the force transmission component 202 abuts against the second force sensor 212. When the force transmission component 202 rotates relative to the base 201, the first end and the second end respectively drive their respective corresponding force sensors to deform. The deformation causes a corresponding change in the output of the circuit module 400. The pronation and supination torque of the forearm is determined by the output of the circuit module 400. The first force sensor 206 and the second force sensor 212 are both fixedly arranged relative to the base 201.

[0044] By setting a first force sensor 206 and a second force sensor 212, which are respectively driven by the first and second ends of the force transmission member 202 to deform, the force acting on the first force sensor 206 and the second force sensor 212 can be obtained according to the magnitude of the deformation, thereby obtaining the torque transmitted by the force transmission member 202. Using the above structural form to measure torque significantly reduces the volume of the force sensing structure compared to directly using a torque sensor. Furthermore, it makes the component for measuring torque unaffected by the thickness of the rehabilitation patient's forearm.

[0045] Specifically, in this embodiment, both the first force sensing element 206 and the second force sensing element 212 can be measured using a force-sensitive resistor (FSR) sensor. The force-sensitive resistor has a long strip structure. One end of the strip structure receives the force transmitted through the first and second ends of the force transmission member 202 and deforms accordingly. The output signal of the force-sensitive resistor is related to the degree of deformation. The other end of the strip structure is used for electrical connection with the circuit in the circuit module 400.

[0046] The first end and the second end of the force transmission member 202 do not refer to the two ends of the force transmission member 202 in the length direction, but can be local edges of the force transmission member 202 on both sides of the rotation axis relative to the base 201. For example, in this embodiment, the first end is... Figure 3 The left end of the force transmission component 202 shown, while the second end is... Figure 3 The right end of the force transmission component 202 shown.

[0047] Specifically, the force transmission component 202 can be connected to the base 201 by means of the cylindrical pin 204 in the figure, which rotates relative to the base 201. The axis of the cylindrical pin 204, that is, the axis of rotation of the force transmission component 202 relative to the base 201, is parallel to the axis of rotation of the force sensing mechanism 200 relative to the guide rail mechanism 300.

[0048] As shown in Figure 2 and Figure 3 Optionally, the force sensing mechanism 200 further comprises a first spring 208 and a second spring 214, the first spring 208 is located between the first end and the first force sensing element 206, and the second spring 214 is located between the second end and the second force sensing element 212, the first spring 208 and the second spring 214 are used to apply forces in the same direction to the force transmission member 202; and when the forearm is not rotated forward or backward, the first spring 208 and the second spring 214 apply torques of the same size and opposite directions relative to the rotation axis of the force transmission member 202; the stiffness of the first spring 208 and the second spring 214 is configured to make the rotation angle of the force transmission member 202 relative to the base 201 within 5°.

[0049] By setting the first spring 208 and the second spring 214, a pre-tightening torque can be generated on the force transmission member 202 when the forearm is not rotated forward or backward, preventing the torque on the force transmission member 202 from being difficult to measure when the rotation amplitude is small due to the gap. Moreover, by setting the springs on both sides of the rotation axis of the force transmission member 202, the first spring 208 or the second spring 214 can be used to balance the torque transmitted by the force transmission member 202, reduce the stress on the force transmission member 202, and slow down the wear of the force transmission member 202 and the parts that pivotally connect the force transmission member 202.

[0050] Among them, the first spring 208 and the second spring 214 are respectively located on both sides of the rotation axis of the force transmission member 202 relative to the base 201, and the positions of the two springs subjected to the force of the force transmission member 202 are the same distance relative to the transmission center of the force transmission member 202. Or it can also be understood that the structure of the force transmission member 202 for applying force to the first spring 208 and the second spring 214 is mirror-symmetrically arranged relative to the cylindrical pin 204.

[0051] As shown in Figure 2 and Figure 3 Optionally, the force sensing mechanism 200 further comprises a spring seat 203, and the first spring 208 and the second spring 214 are respectively sleeved in the spring seat 203; the force transmission member 202 comprises a first lug 2021 and a second lug 2022, the first lug 2021 abuts against the first spring 208, and the second lug 2022 abuts against the second spring 214.

[0052] By loading the first spring 208 and the second spring 214 into the spring seat 203, the spring seat 203 can limit the first spring 208 and the second spring 214 in the radial direction, preventing the end of the first spring 208 and the second spring 214 abutting the force transmission member 202 from bending due to radial movement during rotation of the force transmission member 202, and deviating from the original position. By providing the first lug 2021 and the second lug 2022, the force transmission member 202 can be extended to increase the contact area with the first spring 208 and the second spring 214, improving the stability of operation.

[0053] The first through hole 2031 is provided in the region of the spring seat 203 corresponding to the first spring 208, for the first spring 208 and the second spring 214 to pass through. The second through hole 2032 is provided in the region of the spring seat 203 corresponding to the second spring 214, for the second spring 214 to pass through. The first through hole 2031 and the second through hole 2032 are arranged in parallel, so the first spring 208 and the second spring 214 are also arranged in parallel. The first lug 2021 and the second lug 2022 are located on the side of the force transmission member 202 away from the gripping mechanism 100, and are located at approximately the middle of the force transmission member 202 in terms of height, thereby preventing the first lug 2021 and the second lug 2022 from interfering with other components when the force transmission member 202 rotates around the cylindrical pin 204. In other words, the space reserved in the force sensing mechanism 200 to ensure rotation of the force transmission member 202 can be reduced.

[0054] In fact, in this embodiment, the rotation of the force transmission member 202 is caused by the deformation of the first spring 208 and the second spring 214 in order to balance the torque acting on the force transmission member 202 when transmitting torque. Therefore, the rigidity of the first spring 208 and the second spring 214 is designed to be relatively large, so that the rotation angle of the force transmission member 202 is not too large, and the displacement of the lower end of the first spring 208 and the second spring 214 in the left-right direction shown in FIG. 6 can also be completely controlled, and will not deviate significantly. Figure 3

[0055] As shown in FIG. 6, the first spring 208 and the second spring 214 are arranged in parallel on the force transmission member 202, and the first lug 2021 and the second lug 2022 are arranged on the side of the force transmission member 202 away from the gripping mechanism 100. Figure 2 Figure 3 As shown in FIG. 6, the first spring 208 and the second spring 214 are arranged in parallel on the force transmission member 202, and the first lug 2021 and the second lug 2022 are arranged on the side of the force transmission member 202 away from the gripping mechanism 100.

[0056] ​​By setting the third spring 210 and the fourth spring 216 to abut the first spring 208 and the second spring 214 from the opposite sides of the first lug 2021 and the second lug 2022 respectively, the torque transmitted by the force transmission member 202 can be balanced by the plurality of springs from different directions, so that the force transmission member 202 is balanced, thereby reducing the load on the force transmission member 202 and slowing down the wear speed.

[0057] Specifically, in the present embodiment, a counterbore can be provided on the base 201, specifically, a first counterbore 2011 is provided in the region corresponding to the third spring 210 to accommodate the third spring 210, and a second counterbore 2012 is provided in the region corresponding to the fourth spring 216 to accommodate the fourth spring 216. When the force transmission member 202 does not transmit torque, the third spring 210 and the fourth spring 216 are arranged in parallel, and most of the third spring 210 and the fourth spring 216 are accommodated in the third counterbore or the fourth counterbore.

[0058] As shown in Figure 2 and Figure 3 Optionally, the first spring 208 and the second spring 214 are both compression springs, and the two ends of the first spring 208 and the two ends of the second spring 214 are respectively provided with a gasket.

[0059] By providing a gasket at the two ends of the first spring 208 and the second spring 214, a gasket of appropriate thickness can be used to ensure that when the forearm is not rotated forward or backward, the first spring 208 and the second spring 214 are both in a compressed state, but only a small force is applied to the first force sensing element 206 and the second force sensing element 212. On the one hand, it helps to reduce the overall load level of the first force sensing element 206 and the second force sensing element 212, prolonging their service life, and on the other hand, it can also reduce the output signal strength of the two in this state, so that when the forearm is rotated, the signal received by the device receiving the signal is a larger proportion of the variable of the signal rather than the inherent size of the signal, which helps to improve the resolution and accuracy of detection.

[0060] The first spring 208 has a first upper spring pad 207 on its upper side, positioned between the upper end of the first spring 208 and the first force sensor 206. The first lower spring pad 209 is positioned between the lower end of the first spring 208 and the first lug 2021 on its lower side. The first upper spring pad 207 and the first lower spring pad 209 can adjust the initial pre-compression of the first spring 208. The second spring 214 has a second upper spring pad 213 on its upper side, positioned between the upper end of the second spring 214 and the second force sensor 212. The second lower spring pad 215 is positioned between the lower end of the second spring 214 and the second lug 2022 on its lower side. The second upper spring pad 213 and the second lower spring pad 215 can adjust the initial pre-compression of the second spring 214.

[0061] like Figure 2 and Figure 3 As shown, optionally, the force sensing mechanism 200 also includes a first sensor base 205 and a second sensor base 211. The first sensor base 205 and the second sensor base 211 are both fixedly disposed relative to the base 201. The first force sensing element 206 is fixedly installed in the first sensor base 205, and the second force sensing element 212 is fixedly installed in the second sensor base 211.

[0062] By providing a first sensor base 205 and a second sensor base 211, the first force sensor 206 and the second force sensor 212 are respectively accommodated and fixed. When the force transmission member 202 applies pressure to the first force sensor 206, the first sensor base 205 can support the first force sensor 206, preventing significant bending deformation of the first force sensor 206 and thus avoiding distortion of the detection results. When the force transmission member 202 applies pressure to the second force sensor 212, the second sensor base 211 can support the second force sensor 212, preventing significant bending deformation of the second force sensor 212 and thus avoiding distortion of the detection results.

[0063] Specifically, in this embodiment, using Figure 3 Taking the direction shown as an example, the first sensor seat 205 and the second sensor seat 211 are both fixedly mounted on the upper side of the spring seat 203 by male threaded connectors such as screws or bolts, and the spring seat 203 is fixedly mounted on the base 201 by male threaded connectors such as screws or bolts. Therefore, the first sensor seat 205 and the second sensor seat 211 are fixedly set relative to the base 201.

[0064] Figure 4 This is a schematic diagram of the circuit module in the forearm pronation and supination sensing device provided in Embodiment 1 of this application. Figure 4As shown, the circuit module 400 comprises a reference power supply 401, an amplifier power supply 402, a first operational amplifier 403, a first feedback resistor 404, a first decoupling capacitor 405, a second operational amplifier 406, a second feedback resistor 407, a second decoupling capacitor 408, and a processor 409; the positive input terminals of the first operational amplifier 403 and the second operational amplifier 406 are both grounded; the first feedback resistor 404 and the first decoupling capacitor 405 are connected in parallel and both connected between the negative input terminal and the output terminal of the first operational amplifier 403; the second feedback resistor 407 and the second decoupling capacitor 408 are connected in parallel and both connected between the negative input terminal and the output terminal of the second operational amplifier 406; the first force sensing element 206 is connected between the reference power supply 401 and the negative input terminal of the first operational amplifier 403, and the second force sensing element 212 is connected between the reference power supply 401 and the negative input terminal of the second operational amplifier 406; the output terminal of the first operational amplifier 403 is connected to the first analog-to-digital converter of the processor 409, and the output terminal of the second operational amplifier 406 is connected to the second analog-to-digital converter of the processor 409.

[0065] The first operational amplifier 403 and the second operational amplifier 406 are added in the circuit module 400, and the core is to solve the problems of weakness, nonlinearity, impedance mismatch, etc. of the original signal, and to optimize the signal quality to adapt to the subsequent circuit processing. The first operational amplifier 403 and the second operational amplifier 406 both form a reverse amplifier circuit, the first feedback resistor 404 is connected between the negative input terminal and the output terminal of the first operational amplifier 403, and the second feedback resistor 407 is connected between the negative input terminal and the output terminal of the second operational amplifier 406, which can form a negative feedback loop, stabilize the amplification factor, and make the operational amplifier work in the linear region; the first decoupling capacitor 405 is connected between the negative input terminal and the output terminal of the first operational amplifier 403, and the second decoupling capacitor 408 is connected between the negative input terminal and the output terminal of the second operational amplifier 406, which can filter out high-frequency power supply noise and stabilize the operation of the operational amplifier.

[0066] Among them, the first pin 2061 of the first force sensing element 206 is connected to the reference power supply 401, and the second pin 2062 of the first force sensing element 206 is connected to the negative input terminal of the first operational amplifier 403. The third pin 2121 of the second force sensing element 212 is connected to the reference power supply 401, and the fourth pin 2122 of the second force sensing element 212 is connected to the negative input terminal of the second operational amplifier 406. The first operational amplifier 403 and the second operational amplifier 406 are also connected to the amplifier power supply 402.

[0067] The output voltage VL of the first force sensing element is -Vref x R404 / R206, and the output voltage VR of the second force sensing element 212 is -Vref x R407 / R212, wherein the Vref of the reference power supply 401 is a negative voltage of -0.25V to -1.25V, R404 represents the resistance value of the first feedback resistor 404, which can be selected as 100KΩ, R206 represents the resistance value of the first force sensing element 206, which varies between 1kΩ and 100kΩ, R407 represents the resistance value of the second feedback resistor 407, which can be selected as 100KΩ, and R212 represents the resistance value of the second force sensing element 212, which varies between 1kΩ and 100kΩ. Since Vref is a negative voltage, the output voltage VL of the first force sensing element 206 and the output voltage VR of the second force sensing element 212 are both positive voltage values. Since the resistance value of the force sensing resistor decreases when subjected to pressure, the output voltages VL and VR are the smallest when there is no pressure, and the greater the pressure, the greater the output voltages VL and VR.

[0068] The operational amplifier can amplify weak signals and reduce quantization errors: The voltage signal output by the force sensing resistor through the voltage dividing circuit is usually a weak signal of millivolts, and the resistance-pressure relationship of the force sensing resistor is usually nonlinear. If the weak signal is directly connected to the first analog-to-digital converter and the second digital-to-analog converter, the signal details are easily lost due to the limited resolution of the digital-to-analog converter. The high gain characteristic of the operational amplifier can amplify the weak signal to an amplitude that can be accurately recognized by the digital-to-analog converter. For example, a 10mV force sensing resistor output signal amplified by an operational amplifier with a gain of 100 becomes 1V, which not only allows the digital-to-analog converter to clearly capture the signal change, but also reduces the quantization error ratio. When an 8-bit digital-to-analog converter directly processes a 1V full-scale signal, the quantization interval is 3.9mV. After amplifying the signal by 10 times, the quantization error ratio is reduced from 0.39% to 0.039%, greatly improving the accuracy of pressure detection.

[0069] Signal linearization and simplified data processing: The resistance of the force sensing resistor has a logarithmic relationship with the pressure, which will cause the output voltage curve to change nonlinearly with the pressure, increasing the difficulty of subsequent data interpretation. Designing the operational amplifier as a current-voltage conversion circuit can make the output voltage have a linear relationship with the conductance of the force sensing resistor, which is the inverse of the resistance. Therefore, the output voltage will increase linearly with the increase of the pressure, which not only optimizes the signal resolution, but also eliminates the need for complex algorithms to correct nonlinear errors, making the pressure value calculation more simple.

[0070] Achieving impedance matching and avoiding signal attenuation: Force sensors have high output impedance, while the input impedance of subsequent digital-to-analog converter pins or control chips may be low. Direct connection results in a significant signal voltage drop across the force sensor's output impedance due to impedance mismatch, leading to severe signal attenuation and distortion. Operational amplifiers (op-amps) feature high input impedance and low output impedance. With a high input impedance, they consume almost no signal current when connected to a force sensor, allowing for complete acquisition of the original signal. The low output impedance ensures efficient transmission of the processed signal to subsequent low-impedance loads, guaranteeing lossless signal transmission. For example, if the force sensor's output impedance is 10kΩ while the load's input impedance is only 100Ω, an op-amp effectively solves the impedance mismatch problem.

[0071] Noise suppression and signal-to-noise ratio improvement: The voltage divider circuit of a force-sensitive resistor is susceptible to power supply fluctuations and the surrounding electromagnetic environment, causing noise to be mixed into the output signal. The operational amplifier, employing differential amplification and other circuit designs, has extremely low inherent noise and significantly suppresses mixed common-mode noise while amplifying the useful signal. For example, if the force-sensitive resistor's output signal contains 1mV of noise, after the 10mV useful signal is amplified by the operational amplifier, the useful signal becomes 1V, and the noise is only amplified to a small amplitude, significantly improving the signal-to-noise ratio. This allows subsequent circuits to accurately identify signal changes caused by pressure and avoids misjudgments of pressure due to noise interference.

[0072] Before use, both the first force sensor 206 and the second force sensor 212 need to be calibrated. The calibration steps are as follows:

[0073] (1) Prepare weights of known weight, such as 50g, 100g, 200g, 500g, and 1000g weights;

[0074] (2) Press the first force sensor 206 and the second force sensor 212 together. Figure 4 After connecting the circuit module 400, each weight is evenly pressed onto the sensor, and the output voltage V corresponding to the weight P of the weight is recorded.

[0075] (3) Using multiple sets of data, each set of data includes weight P and voltage V, fit the corresponding relationship P=a×V+b according to the linear formula;

[0076] After calibration, the characteristic curves of the first force sensor, PL = aL × VL + bL, and the characteristic curves of the second force sensor, PR = aR × VR + bR, are obtained.

[0077] Figure 5 The force analysis diagram of the force sensing mechanism when the forearm pronation and supination sensing device provided in Embodiment 1 of this application is applied to the right forearm pronation. (See diagram below.) Figure 5As shown, X0 represents the horizontal direction, Y0 represents the vertical direction, X1 represents the direction parallel to the base, Y1 represents the direction perpendicular to the base, the right forearm pronation (or left forearm supination) joint torque is applied when the right forearm pronation (or left forearm supination) angle is φ, and the force sensing mechanism 200 rotates counterclockwise by an angle of φ relative to the guide rail mechanism 300 - the angle between the coordinate axis X1 and the coordinate axis X0, which can also be considered as the angle between the coordinate axis Y1 and the coordinate axis Y0. The force transmission member 202 rotates counterclockwise by an angle of θ relative to the base 201 under the action of the right forearm pronation (or left forearm supination) joint torque, the third spring 210 and the second spring 214 are further compressed, and the output voltage of the second force sensing element 212 increases to VR1; the first spring 208 is in a relaxed state, and the output voltage of the first force sensing element 206 is zero. At this time, the compression amount of the third spring 210 is ΔXL=RL×sin(θ), and the compression amount of the second spring 214 is ΔXR=RR×sin(θ); the second spring 214 generates a force FR=KR×ΔXR along Y1 downward, and the third spring 210 generates a force FL=KL×ΔXL=KL×(ΔXR×RL / RR)=FR×(KL / KR)×(RL / RR) along Y1 upward. The force FR of the second spring 214 causes the output voltage of the second force sensing element 212 to increase to VR1, according to the characteristic curve FR / g=aR×VR1+bR, where g represents the acceleration of gravity. At this time, the right forearm pronation (or left forearm supination) joint torque M =FR×RR×cos(θ)+FL×RL×cos(θ)=FR×RR×cos(θ)+FR×(KL / KR)×(RL / RR)×RL×cos(θ)=(aR×VR1+bR)×g×(RR+(KL / KR)×(RL / RR)×RL)×cos(θ). Where the stiffness of the third spring 210 is KL, the stiffness of the second spring 214 is KR, the distance from the center of the force transmission member 202 to the first lug 2021 is RL, and the distance from the center of the force transmission member 202 to the second lug 2022 is RR.

[0078] It should be noted that the angle θ of the rotation of the force transmission member 202 relative to the base 201 is independent of the angle φ of the right forearm pronation (or left forearm supination), and only depends on the right forearm pronation (or left forearm supination) joint torque applied to the force sensing mechanism 200 and the design parameters of the mechanism (such as spring stiffness KL / KR, member distance RL / RR, etc.). When the angle θ is small, it can be approximately considered that cos(θ)=1, at this time the right forearm pronation (or left forearm supination) joint torque M and the output voltage VR1 of the second force sensing element 212 are in a linear relationship, in order to maintain the linear relationship, the angle θ is controlled to be within 5° by designing a larger spring stiffness KL and KR.

[0079] When RL=RR and KL=KR, FL=FR, the elastic forces of the third spring 210 and the second spring 214 are equal in size and opposite in direction (the forces in the Y1 direction cancel each other out), which can balance the unilateral load generated during equipment operation, such as the gravity offset of the workpiece, the centrifugal force of the moving assembly, and the external impact load offset, to avoid asymmetric stress on the core components; it can eliminate the deformation of the components caused by "unilateral stress" and prolong the service life of the parts - the force transmission member 202, the cylindrical pin 204, etc.; it can reduce the contact stress concentration caused by the load offset and reduce the wear rate, usually by 30%-50% of uneven wear. Assuming there is no third spring 210, in order to achieve force balance of the force transmission member 202 in the Y1 direction, only the cylindrical pin 204 can provide a support force in the Y1 direction, which is obviously larger than the force of FR, which will increase the stress on the cylindrical pin 204 and accelerate the wear of the cylindrical pin 204.

[0080] Figure 6 The force sensing mechanism stress analysis diagram of the forearm pronation and supination sensing device provided by the embodiment one of the present application is applied to the right forearm supination. As shown in the figure, Figure 6 when the right forearm supination (or left forearm pronation) angle is φ, the right forearm supination (or left forearm pronation) joint torque is applied, the force sensing mechanism 200 rotates counterclockwise by an angle of φ relative to the guide rail mechanism 300, the force transmission member 202 rotates counterclockwise by an angle of θ relative to the base 201 under the action of the right forearm supination (or left forearm pronation) joint torque, the first spring 208 and the fourth spring 216 are further compressed, and the output voltage of the first force sensing element 206 increases to VL1; the second spring 214 is in a relaxed state, and the output voltage of the second force sensing element 212 is zero. At this time, the compression amount of the first spring 208 is △XL=RL×sin(θ), and the compression amount of the fourth spring 216 is △XR=RR×sin(θ); the first spring 208 generates a downward force FL=KL×△XL, and the fourth spring 216 generates an upward force FR=KR×△XR=KR×(△XL×RR / RL)=FL×(KR / KL)×(RR / RL). The force FL of the first spring 208 causes the right sensor to output a voltage of VL1, and according to the characteristic curve FL / g=aL×VL1+bL, where g represents the acceleration of gravity. At this time, the joint torque of the right forearm supination (or left forearm pronation) M = FL×RL×cos(θ)+FR×RR×cos(θ)=FL×RL×cos(θ)+FL×(KR / KL)×(RR / RL)×RR×cos(θ)=(aL×VL1+bL)×g×(RL+(KR / KL)×(RR / RL)×RR)×cos(θ). Where the stiffness of the first spring 208 is KL, and the stiffness of the fourth spring 216 is KR.

[0081] Similarly, the angle θ of the force transmission member 202 relative to the base 201 is independent of the angle φ of the right forearm supination (or left forearm pronation), and only depends on the right forearm supination (or left forearm pronation) joint torque applied to the force sensing mechanism 200 and the design parameters of the mechanism (e.g. spring stiffness KL / KR, member distance RL / RR, etc.). When the angle θ is small, cos(θ) can be approximated as 1, and the right forearm supination (or left forearm pronation) joint torque M is linearly related to the output voltage VL1 of the first force sensing member 206. In order to maintain the linear relationship, the angle θ is controlled to be within 5° by designing a large spring stiffness KL and KR.

[0082] Embodiment Two

[0083] Figure 7 A structure schematic diagram of a rehabilitation robot is provided for Embodiment Two of the present application. As shown in the figure, Embodiment Two also provides a rehabilitation robot, which includes the above-mentioned forearm pronation-supination sensing device. Figure 7

[0084] By providing the above-mentioned forearm pronation-supination sensing device in the rehabilitation robot, the rehabilitation robot has all the advantages of the above-mentioned forearm pronation-supination sensing device, which will not be repeated here.

[0085] Specifically, the rehabilitation robot can be an upper limb rehabilitation robot, which includes a shoulder abduction-adduction joint 501, a shoulder flexion-extension joint 502, a shoulder internal-external rotation joint 503, an elbow flexion-extension joint 504, a forearm pronation-supination joint 505 and a wrist dorsiflexion-palmarflexion joint 506 connected in sequence, wherein the forearm pronation-supination joint 505 adopts the above-mentioned forearm pronation-supination sensing device.

[0086] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art, without departing from the spirit and scope of the present application, can make various modifications and changes, therefore the protection scope of the present application should be subject to the scope defined by the claims.

[0087] ​Finally, it should be noted that, in this document, the term "only" is used simply to set off from one entity or action to another, and does not necessarily require or imply that there is any such actual relationship or order between the entities or actions. Also, the term "comprising" or any other variation thereof is intended to cover the non-exclusive inclusion of the elements listed, such that processes, methods, articles, or apparatuses that comprise these elements, but that also comprise other elements, are not to be precluded from the scope of the application. In the absence of further limitation, the elements defined by the statement "comprising a" do not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the stated elements.

[0088] In the above embodiments, the description of orientation such as "upper", "lower" and the like are based on the drawings shown.

[0089] The above description of disclosed embodiments provides enabling teaching to a person skilled in the art to carry out or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application.

[0090] Therefore, the application should not be limited to the embodiments shown herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A forearm pronation and supination sensing device, characterized in that, The device includes a gripping mechanism (100), a force sensing mechanism (200), a guide rail mechanism (300), and a circuit module (400). The gripping mechanism (100) is connected to the force sensing mechanism (200), and the force sensing mechanism (200) is rotatably connected to the guide rail mechanism (300). The force sensing mechanism (200) is electrically connected to the circuit module (400), and the rotation axis of the force sensing mechanism (200) relative to the guide rail mechanism (300) is configured as the axis of forearm pronation or supination. The force sensing mechanism (200) is fixedly mounted on the restraint mechanism (600), which is used to restrain the forearm to restrict the movement of the forearm to pronation or supination only. The force sensing mechanism (200) includes a force transmitting member (202) and a base (201). The force transmitting member (202) is fixedly connected to the gripping mechanism (100) and is rotatably disposed relative to the base (201). The first end of the force transmitting member (202) abuts against the first force sensing element (206). The second end of the component (202) abuts against the second force sensing component (212); when the force transmission component (202) rotates relative to the base (201) under the action of the forearm's pronation and supination torque, the first end and the second end respectively drive their respective force sensing components to deform, and the deformation causes the output of the circuit module (400) to change accordingly. The pronation and supination torque of the forearm is determined by the output of the circuit module (400); the first force sensing component (206) and the second force sensing component (212) are both fixedly set relative to the base (201).

2. The forearm pronation and supination sensing device according to claim 1, characterized in that, The force sensing mechanism (200) further includes a first spring (208) and a second spring (214). The first spring (208) is located between the first end and the first force sensing element (206), and the second spring (214) is located between the second end and the second force sensing element (212). The first spring (208) and the second spring (214) are used to apply a force in the same direction to the force transmission member (202). When the forearm is not rotated forward or backward, the first spring (208) and the second spring (214) apply a torque of the same magnitude but opposite direction relative to the rotation axis of the force transmission member (202). The stiffness of the first spring (208) and the second spring (214) is configured such that the rotation angle of the force transmission member (202) relative to the base (201) is within 5°.

3. The forearm pronation and supination sensing device according to claim 2, characterized in that, The force sensing mechanism (200) further includes a spring seat (203), in which the first spring (208) and the second spring (214) are respectively mounted; the force transmission member (202) includes a first lug (2021) and a second lug (2022), in which the first lug (2021) abuts against the first spring (208) and the second lug (2022) abuts against the second spring (214).

4. The forearm pronation and supination sensing device according to claim 3, characterized in that, The force sensing mechanism (200) further includes a third spring (210) and a fourth spring (216), wherein the third spring (210) and the first spring (208) abut against the first lug (2021) from opposite sides, and the fourth spring (216) and the second spring (214) abut against the second lug (2022) from opposite sides.

5. The forearm pronation and supination sensing device according to claim 3, characterized in that, Both the first spring (208) and the second spring (214) are compression springs, and the ends of the first spring (208) and the second spring (214) are respectively provided with washers.

6. The forearm pronation and supination sensing device according to claim 1, characterized in that, The force sensing mechanism (200) further includes a first sensor base (205) and a second sensor base (211). The first sensor base (205) and the second sensor base (211) are both fixedly disposed relative to the base (201). The first force sensing element (206) is fixedly installed in the first sensor base (205), and the second force sensing element (212) is fixedly installed in the second sensor base (211).

7. The forearm pronation and supination sensing device according to any one of claims 1-5, characterized in that, The circuit module (400) includes a reference power supply (401), an amplifier power supply (402), a first operational amplifier (403), a first feedback resistor (404), a first decoupling capacitor (405), a second operational amplifier (406), a second feedback resistor (407), a second decoupling capacitor (408), and a processor (409); the positive input terminals of the first operational amplifier (403) and the second operational amplifier (406) are both grounded; the first feedback resistor (404) and the first decoupling capacitor (405) are connected in parallel and are both connected between the negative input terminal and the output terminal of the first operational amplifier (403); the second feedback resistor (407) The first force sensor (206) and the second force sensor (212) are connected in parallel and are both connected between the negative input terminal and the output terminal of the second operational amplifier (406); the first force sensor (206) is connected between the reference power supply (401) and the negative input terminal of the first operational amplifier (403), and the second force sensor (212) is connected between the reference power supply (401) and the negative input terminal of the second operational amplifier (406); the output terminal of the first operational amplifier (403) is connected to the first analog-to-digital converter of the processor (409), and the output terminal of the second operational amplifier (406) is connected to the second analog-to-digital converter of the processor (409).

8. A rehabilitation robot, characterized in that, The rehabilitation robot includes the forearm pronation and supination sensing device according to any one of claims 1-7.

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