Front arm pronation and supination sensing device and rehabilitation robot

Abstract

The invention provides a forearm pronation and supination sensing device and a rehabilitation robot, relates to the technical field of rehabilitation exercise, and aims to solve the problem that forearm pronation and supination torque is difficult to measure. The forearm forward and backward rotation 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 with the guide rail mechanism in a relative rotation mode, and the force sensing mechanism is electrically connected to the circuit module. The rotation axis of the force sensing mechanism relative to the guide rail mechanism is configured to be the axis where the front arm rotates forwards or backwards. The forearm pronation and supination torque measuring device can conveniently measure the forearm pronation and supination torque.

Description

Technical Field

[0001] This application relates to the field of rehabilitation exercise technology, and more specifically, to a forearm pronation and supination sensing device and a rehabilitation robot. Background Technology

[0002] To address the shortage of stroke rehabilitation physicians, rehabilitation robots have become a research hotspot in the field of stroke rehabilitation treatment. They can assist or even replace physicians in providing patients with more continuous, effective, and targeted rehabilitation training and treatment, alleviating the shortage of rehabilitation medical human resources. Moreover, they can record patients' treatment data in real time, providing objective evidence for disease assessment and treatment plan improvement.

[0003] Upper limb rehabilitation training is crucial for patients to regain their daily living abilities, especially the coordinated operation of the elbow and forearm, which greatly expands the range of hand motion. Estimating the torque in the elbow and forearm can reveal the patient's motor intentions; this process is a core component of active rehabilitation training and has become a focus of medical research. Although there is extensive research on elbow torque, which is widely used in human-computer interaction control, research on forearm pronation and supination joint torque is relatively limited. Traditional methods using torque sensors to measure joint torque are rarely used for forearm pronation and supination joints due to the large size and difficulty in installing torque sensors. To address the challenge of measuring forearm pronation and supination joint torque, some institutions have proposed data modeling-based methods.

[0004] For example, CN118303873A (publication date 2024.07.09) discloses a method and apparatus for predicting forearm joint torque, a method for obtaining a prediction model, and an apparatus. The method includes: acquiring forearm muscle motion data collected by a wearable device during the rotation of the human forearm, and real-time joint torque of the human forearm during the rotation of the human forearm synchronously collected by a verification device, and extracting forearm rotational motion features from the forearm muscle motion data; then, performing regression training on the model based on the forearm rotational motion features and real-time joint torque to obtain a model that can quickly and accurately predict forearm joint torque, especially for scenarios such as upper limb rehabilitation training, where accurate estimation of forearm joint torque is beneficial for rehabilitation training.

[0005] The aforementioned methods indirectly predict forearm joint torque by establishing a model of forearm joint torque using forearm muscle movement data. This requires collecting a large amount of data, and accuracy depends on the modeling precision. It is time-consuming, labor-intensive, and accuracy cannot be guaranteed. To address these issues, this solution 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 using a force-sensitive resistor sensor, achieving rapid and accurate force sensing. Summary of the Invention

[0006] The first aspect of this application aims to provide a forearm pronation and supination sensing device to solve the technical problem that existing forearm pronation and supination torques are difficult to measure.

[0007] The forearm pronation and supination sensing device provided in the first aspect of this application includes a gripping mechanism, a force sensing mechanism, a guide rail mechanism, and a circuit module. The gripping mechanism is connected to the force sensing mechanism, and the force sensing mechanism is rotatably connected to the guide rail mechanism. 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 beneficial effects of the forearm pronation and supination sensing device in this application are: When a rehabilitation patient's forearm rotates forward or backward, the torque transmitted by the patient through the gripping mechanism can be directly measured by using a force sensing mechanism, without the need for a bulky torque sensor. It is also easy to install and, compared to data modeling methods, can ensure greater measurement accuracy.

[0009] In an optional technical solution, the force sensing mechanism is fixedly installed on the restraint mechanism, which is used to restrain the forearm to restrict the movement of the forearm to only pronation or supination.

[0010] In an optional technical solution, the force sensing mechanism includes a force transmission component and a base. The force transmission component is fixedly connected to the gripping mechanism and is rotatably disposed relative to the base. A first end of the force transmission component abuts against a first force sensor, and a second end of the force transmission component abuts against a second force sensor. When the force transmission component rotates relative to the base under the action of the forearm's pronation and supination torque, the first end and the second end respectively drive their corresponding force sensors to deform. The deformation causes a corresponding change in the output of the circuit module, and the pronation and supination torque of the forearm is determined by the output of the circuit module. Both the first force sensor and the second force sensor are fixedly disposed relative to the base.

[0011] In an optional technical solution, the force sensing mechanism further includes a first spring and a second spring. The first spring is located between the first end and the first force sensing element, and the second spring is located between the second end and the second force sensing element. The first spring and the second spring are used to apply a force in the same direction to the force transmission member. When the forearm is not rotated forward or backward, the first spring and the second spring apply torques of the same magnitude but opposite directions relative to the rotation axis of the force transmission member. The stiffness of the first spring and the second spring is configured such that the rotation angle of the force transmission member relative to the base is within 5°.

[0012] In an optional technical solution, the force sensing mechanism further includes a spring seat, in which the first spring and the second spring are respectively mounted; the force transmission component includes a first lug and a second lug, in which the first lug abuts against the first spring and the second lug abuts against the second spring.

[0013] In an optional technical solution, the force sensing mechanism further includes a third spring and a fourth spring, wherein the third spring and the first spring abut against the first lug from opposite sides, and the fourth spring and the second spring abut against the second lug from opposite sides.

[0014] In an optional technical solution, both the first spring and the second spring are compression springs, and the ends of the first spring and the second spring are respectively provided with washers.

[0015] In an optional technical solution, the force sensing mechanism further includes a first sensor seat and a second sensor seat, both of which are fixedly disposed relative to the base. The first force sensing element is fixedly installed in the first sensor seat, and the second force sensing element is fixedly installed in the second sensor seat.

[0016] In an optional technical solution, the circuit module includes 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 positive input terminals of both the first and second operational amplifiers are grounded; the first feedback resistor and the first decoupling capacitor are connected in parallel and are both connected between the negative input terminal and the output terminal of the first operational amplifier; the second feedback resistor and the second decoupling capacitor are connected in parallel and are both connected between the negative input terminal and the output terminal of the second operational amplifier; the first force sensor is connected between the reference power supply and the negative input terminal of the first operational amplifier, and the second force sensor is connected between the reference power supply and the negative input terminal of the second operational amplifier; the output terminal of the first operational amplifier is connected to the first analog-to-digital converter of the processor, and the output terminal of the second operational amplifier is connected to the second analog-to-digital converter of the processor.

[0017] The second aspect of this application aims to provide a rehabilitation robot to solve the technical problem of the difficulty in measuring forearm pronation and supination torque.

[0018] The rehabilitation robot provided in the second aspect of this application includes the aforementioned forearm pronation and supination sensing device.

[0019] By incorporating the aforementioned forearm pronation and supination sensing device into the rehabilitation robot, the rehabilitation robot acquires all the advantages of the aforementioned forearm pronation and supination sensing device, which will not be elaborated upon here. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments or background art of this application, the drawings used in the description of the embodiments or background art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the forearm pronation and supination sensing device provided in Embodiment 1 of this application.

[0022] Figure 2 This is a schematic diagram of the force sensing mechanism in the forearm pronation and supination sensing device provided in Embodiment 1 of this application.

[0023] Figure 3 This is a cross-sectional view of the force sensing mechanism in the forearm pronation and supination sensing device provided in Embodiment 1 of this application.

[0024] 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.

[0025] 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.

[0026] Figure 6 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 supination.

[0027] Figure 7 This is a schematic diagram of the structure of the rehabilitation robot provided in Embodiment 2 of this application.

[0028] Explanation of reference numerals in the attached figures: 100 - Grip mechanism; 200 - Force sensing mechanism; 300 - Guide rail mechanism; 400 - Circuit module; 600 - Restraint mechanism; 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; 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; 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

[0029] 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.

[0030] Example 1: 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.

[0031] When the forearm of a rehabilitation patient is rotated forward or backward, the torque transmitted by the patient through the gripping mechanism 100 can be directly measured by the force sensing mechanism 200 without the need for a bulky torque sensor. It is also easy to install and can ensure measurement accuracy better than data modeling methods.

[0032] The grip structure includes a grip handle, which is fixedly connected to a transmission component, which in turn is fixedly connected to the force transmission component 202 described later. Of course, in other implementations, the grip structure can use other shapes of gripped components, such as ellipsoidal or olive-shaped, as long as the shape is convenient for the operator to grasp.

[0033] The guide rail mechanism 300 may include guide rails distributed over a semicircle, the center of which is located on the rotation axis of the force sensing mechanism 200 relative to the guide rails, i.e., also on the axis of forearm pronation or supination. When the forearm pronates or supinates, the hand generates torque on the gripping mechanism 100, which can transmit the torque to the force sensing mechanism 200, which can detect the torque. The relative rotational connection between the force sensing mechanism 200 and the guide rail mechanism 300 means that the force sensing mechanism 200 can only rotate about the axis of forearm pronation or supination, and cannot move along this axis relative to the guide rail mechanism 300, or pitch along the rotation axis of the elbow joint.

[0034] like Figure 1 As shown, optionally, the force sensing mechanism 200 is fixedly mounted on the restraint mechanism 600, which is used to apply restraint to the forearm to restrict the movement of the forearm to pronation or supination only.

[0035] By setting the restraint mechanism 600, excessive degrees of freedom, such as elbow flexion and extension, wrist deviation, and shoulder compensation, can be restricted, preventing patients from deviating from the correct training movements due to insufficient muscle strength or motor control disorders.

[0036] The restraint mechanism 600 includes a flexible restraint strap that is fixedly connected to the base 201 described later. After passing through the restraint hole, the restraint strap is folded in the opposite direction to tighten the arm of the rehabilitation person. It is then fastened using a method such as Velcro or Hook and Loop. This can effectively inhibit the movement of the rehabilitation person's forearm relative to the base 201, thereby preventing and reducing the movement in the remaining degrees of freedom and avoiding interference with the force sensing mechanism 200 in measuring the magnitude of the force.

[0037] Figure 2 This is a schematic diagram of the force sensing mechanism in the forearm pronation and supination sensing device provided in Embodiment 1 of this application. Figure 3 This is a cross-sectional view of the force sensing mechanism in the forearm pronation and supination sensing device provided in Embodiment 1 of this application. 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.

[0038] 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.

[0039] 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.

[0040] 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, and the second end is... Figure 3 The right end of the force transmission component 202 shown.

[0041] 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.

[0042] like Figure 2 and Figure 3 As shown, optionally, 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 torques of the same magnitude but 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 such that the rotation angle of the force transmission member 202 relative to the base 201 is within 5°.

[0043] By setting the first spring 208 and the second spring 214, a preload 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 clearance. Moreover, by setting springs on both sides of the rotation axis of the force transmission member 202, the torque transmitted by the force transmission member 202 can be balanced by the first spring 208 or the second spring 214, reducing the force on the force transmission member 202 and slowing down the wear of the force transmission member 202 and the parts pivotally connected to the force transmission member 202.

[0044] The first spring 208 and the second spring 214 are located on opposite sides of the rotation axis of the force transmission member 202 relative to the base 201, and the positions where they are subjected to the force of the force transmission member 202 are equidistant from the transmission center of the force transmission member 202. Alternatively, it can be understood that the force transmission member 202, which is used to apply force to the first spring 208 and the second spring 214, is arranged symmetrically with respect to the cylindrical pin 204.

[0045] like Figure 2 and Figure 3 As shown, optionally, 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 component 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.

[0046] By mounting the first spring 208 and the second spring 214 into the spring seat 203, the spring seat 203 can radially limit the first spring 208 and the second spring 214, preventing them from bending and disengaging from their original positions due to radial movement at the ends of the first spring 208 and the second spring 214 that abut against the force transmission member 202 during rotation. Furthermore, the first lug 2021 and the second lug 2022 allow for the extension of the force transmission member 202, increasing the contact area with the first spring 208 and the second spring 214 and improving operational stability.

[0047] A first through hole 2031 is provided in the area of ​​the spring seat 203 corresponding to the first spring 208, allowing the first spring 208 and the second spring 214 to pass through. A second through hole 2032 is provided in the area of ​​the spring seat 203 corresponding to the second spring 214, allowing 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 approximately located at the middle of the force transmission member 202 in terms of height. This prevents 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, it reduces the space reserved in the force sensing mechanism 200 to ensure the rotation of the force transmission member 202.

[0048] In fact, in this embodiment, the rotation of the force transmission component 202 is caused by the deformation of the first spring 208 and the second spring 214 to balance the effect of the torque on the force transmission component 202 when transmitting torque. Therefore, the stiffness of the first spring 208 and the second spring 214 is designed to be larger, so the rotation angle of the force transmission component 202 will not be too large. Therefore, the lower ends of the first spring 208 and the second spring 214 are at... Figure 3 The displacement in the left and right directions shown can also be completely controlled, and there will be no particularly significant deviation.

[0049] like Figure 2 and Figure 3 As shown, optionally, the force sensing mechanism 200 further includes a third spring 210 and a fourth spring 216. The third spring 210 and the first spring 208 abut against the first lug 2021 from opposite sides, respectively. The fourth spring 216 and the second spring 214 abut against the second lug 2022 from opposite sides, respectively.

[0050] By setting a third spring 210 and a fourth spring 216 to abut against the first spring 208 and the second spring 214 from opposite sides of the first lug 2021 and the second lug 2022 respectively, multiple springs can balance the torque from different directions when the force transmission member 202 transmits torque, so that the force transmission member 202 is subjected to force balance, thereby reducing the load on the force transmission member 202 and slowing down its wear rate.

[0051] Specifically, in this embodiment, countersunk holes can be provided on the base 201. Specifically, a first countersunk hole 2011 is provided in the region corresponding to the third spring 210 to accommodate the third spring 210, and a second countersunk hole 2012 is provided in the region corresponding to the fourth spring 216 to accommodate the fourth spring 216. When the force transmission member 202 is not transmitting torque, the third spring 210 and the fourth spring 216 are arranged in parallel, and most of each of the third spring 210 and the fourth spring 216 is accommodated in the third countersunk hole or the fourth countersunk hole.

[0052] like Figure 2 and Figure 3 As shown, optionally, both the first spring 208 and the second spring 214 are compression springs, and washers are provided at both ends of the first spring 208 and the second spring 214 respectively.

[0053] By placing shims at both ends of the first spring 208 and the second spring 214, shims of appropriate thickness can be used to ensure that when the forearm is not rotated forward or backward, both the first spring 208 and the second spring 214 are in a compressed state, but only the first force sensor 206 and the second force sensor 212 are subjected to a small force. On the one hand, this helps to reduce the overall load level of the first force sensor 206 and the second force sensor 212 and extend their service life. On the other hand, it can also reduce the output signal strength of the two in this state. Thus, when the forearm rotates, the signal received by the signal receiving device is more of a variable of the signal than the inherent magnitude of the signal, which helps to improve the resolution and accuracy of the detection.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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, optionally, 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 both the first operational amplifier 403 and the second operational amplifier 406 are 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 406... Resistor 407 and second decoupling capacitor 408 are connected in parallel and both are 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.

[0059] The circuit module 400 incorporates a first operational amplifier 403 and a second operational amplifier 406. The core purpose is to address the weaknesses, nonlinearities, and impedance mismatches of the original signal, while simultaneously optimizing signal quality to suit subsequent circuit processing. Both the first operational amplifier 403 and the second operational amplifier 406 form an inverting amplifier circuit. A first feedback resistor 404 is connected between the negative input and output terminals of the first operational amplifier 403, and a second feedback resistor 407 is connected between the negative input and output terminals of the second operational amplifier 406. This forms a negative feedback loop, stabilizing the amplification factor and ensuring the operational amplifier operates in the linear region. A first decoupling capacitor 405 is connected between the negative input and output terminals of the first operational amplifier 403, and a second decoupling capacitor 408 is connected between the negative input and output terminals of the second operational amplifier 406. This filters out high-frequency power supply noise and stabilizes the operation of the operational amplifiers.

[0060] Specifically, the first pin 2061 of the first force sensor 206 is connected to the reference power supply 401, and the second pin 2062 of the first force sensor 206 is connected to the negative input terminal of the first operational amplifier 403. The third pin 2121 of the second force sensor 212 is connected to the reference power supply 401, and the fourth pin 2122 of the second force sensor 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.

[0061] The output voltage VL of the first force sensor is -Vref × R404 / R206, and the output voltage VR of the second force sensor 212 is -Vref × R407 / R212. Here, Vref of the reference power supply 401 is a negative voltage ranging from -0.25V to -1.25V. R404 represents the resistance value of the first feedback resistor 404, which can be, for example, 100KΩ. R206 represents the resistance value of the first force sensor 206, which varies between 1kΩ and 100kΩ. R407 represents the resistance value of the second feedback resistor 407, which can also be, for example, 100KΩ. R212 represents the resistance value of the second force sensor 212, which also varies between 1kΩ and 100kΩ. Since Vref is a negative voltage, both the output voltage VL of the first force sensor 206 and the output voltage VR of the second force sensor 212 are positive voltage values. Since the resistance of the force-sensitive resistor decreases when it is under pressure, the output voltages VL and VR are at their minimum when there is no pressure. As the pressure increases, the output voltages VL and VR both increase.

[0062] Operational amplifiers can amplify weak signals and reduce quantization errors: The voltage signal output by a force-sensitive resistor through a voltage divider circuit is typically a weak signal in the millivolt range, and the resistance-pressure relationship of the force-sensitive resistor is often non-linear. If this weak signal is directly connected to the first analog-to-digital converter (ADC) and the second digital-to-analog converter (DAC), the limited resolution of the DAC can easily lead to the loss of signal details. The high gain characteristic of operational amplifiers can amplify weak signals to a level that the DAC can accurately recognize. For example, a 10mV force-sensitive resistor output signal, after being amplified by a 100x gain operational amplifier, becomes 1V. This not only allows the DAC to clearly capture signal changes but also reduces the proportion of quantization error. When an 8-bit DAC directly processes a 1V full-scale signal, the quantization interval is 3.9mV. After amplifying the signal by 10 times, the quantization error proportion decreases from 0.39% to 0.039%, significantly improving the accuracy of pressure detection.

[0063] Signal linearization simplifies data processing: The resistance of a force-sensitive resistor has a logarithmic relationship with pressure, which leads to a non-linear curve of its output voltage changing with pressure, increasing the difficulty of subsequent data interpretation. Designing the operational amplifier as a current-to-voltage conversion circuit allows the output voltage to have a linear relationship with the conductance of the force-sensitive resistor, where conductance is the reciprocal of resistance. Therefore, the output voltage increases linearly with increasing pressure, optimizing signal resolution and eliminating the need for complex algorithms to correct non-linear errors, making pressure value calculation much simpler.

[0064] 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.

[0065] 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.

[0066] Before use, both the first force sensor 206 and the second force sensor 212 need to be calibrated. The calibration steps are as follows: (1) Prepare weights of known weight, such as 50g, 100g, 200g, 500g, and 1000g weights; (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. (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; 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.

[0067] 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 in the figure, X0 represents the horizontal direction, Y0 represents the vertical direction, X1 represents the direction parallel to the base, and Y1 represents the direction perpendicular to the base. When the right forearm pronation or left forearm supination angle is φ, the right forearm pronation (or left forearm supination) joint torque is applied. The force sensing mechanism 200 rotates counterclockwise by an angle φ relative to the guide rail mechanism 300—the angle between the coordinate axes X1 and X0, which can also be considered as the angle between the coordinate axes Y1 and Y0. Under the action of the right forearm pronation (or left forearm supination) joint torque, the force transmission component 202 rotates counterclockwise by an angle θ relative to the base 201. 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 of the third spring 210 is ΔXL = RL × sin(θ), and the compression of the second spring 214 is ΔXR = RR × sin(θ). The second spring 214 generates a downward force FR = KR × ΔXR along Y1, and the third spring 210 generates an upward force FL = KL × ΔXL = KL × (ΔXR × RL / RR) = FR × (KL / KR) × (RL / RR). 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 due to gravity. At this point, the joint torque M for right forearm pronation or left forearm supination is 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). Wherein, 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.

[0068] It should be noted that the rotation angle θ of the force transmission component 202 relative to the base 201 is independent of the right forearm pronation (or left forearm supination) angle φ, and depends only 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, component 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 is linearly related to the output voltage VR1 of the second force sensing component 212. In order to maintain the linear relationship, the angle θ is controlled to be within 5° by designing larger spring stiffnesses KL and KR.

[0069] When RL=RR and KL=KR, FL=FR. The elastic forces of the third spring 210 and the second spring 214 are equal in magnitude and opposite in direction (forces in the Y1 direction cancel each other out). This balances the unilateral load generated during equipment operation, such as workpiece gravity offset, centrifugal force of moving components, and external impact load, preventing core components from bearing asymmetrical stress. It can eliminate component deformation caused by "unilateral force" and extend the service life of parts such as force transmission component 202 and cylindrical pin 204. It can reduce the concentration of contact stress caused by unilateral load and reduce the wear rate, typically reducing uneven wear by 30% to 50%. Assuming there is no third spring 210, in order to achieve force balance of force transmission component 202 in the Y1 direction, only cylindrical pin 204 can provide a supporting force in the upward direction along Y1 with a magnitude equal to FR. Obviously, this will increase the force on cylindrical pin 204 and accelerate its wear.

[0070] Figure 6 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 supination. (See diagram below.) Figure 6 As shown in the figure, X0 represents the horizontal direction, Y0 represents the vertical direction, X1 represents the direction parallel to the base, and Y1 represents the direction perpendicular to the base. 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 clockwise by an angle φ relative to the guide rail mechanism 300. Under the action of the right forearm supination (or left forearm pronation) joint torque, the force transmission component 202 rotates clockwise by an angle θ relative to the base 201. 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 of the first spring 208 is ΔXL = RL × sin(θ), and the compression of the fourth spring 216 is ΔXR = RR × sin(θ). The first spring 208 generates a downward force FL = KL × ΔXL, and the fourth spring 216 generates an upward force FR = KR × ΔXR = KR × (ΔXL × RR / RL) = FL × (KR / KL) × (RR / RL). The force FL of the first spring 208 causes the output voltage of the right sensor to increase to VL1. According to the characteristic curve FL / g = aL × VL1 + bL, where g represents the acceleration due to gravity. At this point, the joint torque M during right forearm supination (or left forearm pronation) is 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.

[0071] Similarly, the rotation angle θ of the force transmission component 202 relative to the base 201 is independent of the right forearm supination (or left forearm pronation) angle φ, and depends only on the right forearm supination (or left forearm pronation) joint torque applied to the force sensing mechanism 200 and the mechanism's design parameters (e.g., spring stiffness KL / KR, component distance RL / RR, etc.). When the angle θ is small, it can be approximated that cos(θ) = 1. At this time, the right forearm supination (or left forearm pronation) joint torque M is linearly related to the output voltage VL1 of the first force sensing component 206. In order to maintain the linear relationship, the angle θ is controlled to be within 5° by designing larger spring stiffnesses KL and KR.

[0072] Example 2: Figure 7 This is a schematic diagram of the structure of the rehabilitation robot provided in Embodiment 2 of this application. Figure 7 As shown, Embodiment 2 also provides a rehabilitation robot, including the forearm pronation and supination sensing device described above.

[0073] By incorporating the aforementioned forearm pronation and supination sensing device into the rehabilitation robot, the rehabilitation robot acquires all the advantages of the aforementioned forearm pronation and supination sensing device, which will not be elaborated upon here.

[0074] Specifically, the rehabilitation robot can be an upper limb rehabilitation robot, which includes a shoulder external adduction joint 501, a shoulder flexion and extension joint 502, a shoulder rotation internal and external joint 503, an elbow flexion and extension joint 504, a forearm pronation and supination joint 505, and a wrist dorsiflexion and palmar flexion joint 506 connected in sequence. The forearm pronation and supination joint 505 adopts the aforementioned forearm pronation and supination sensing device.

[0075] While this application discloses the above information, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application shall be determined by the scope defined in the claims.

[0076] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] In the above embodiments, descriptions of directions such as "up" and "down" are based on the accompanying drawings.

[0078] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application.

[0079] Therefore, this application is not to be limited to the embodiments shown herein, but is to 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.

2. The forearm pronation and supination sensing device according to claim 1, characterized in that, 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.

3. The forearm pronation and supination sensing device according to claim 1, characterized in that, 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 rotatably disposed relative to the base (201). 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) under the action of the forearm's pronation and supination torque, 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 disposed relative to the base (201).

4. The forearm pronation and supination sensing device according to claim 3, 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°.

5. The forearm pronation and supination sensing device according to claim 4, 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).

6. The forearm pronation and supination sensing device according to claim 5, 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.

7. The forearm pronation and supination sensing device according to claim 5, 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.

8. The forearm pronation and supination sensing device according to claim 3, 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).

9. The forearm pronation and supination sensing device according to any one of claims 3-7, 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).

10. A rehabilitation robot, characterized in that, The rehabilitation robot includes the forearm pronation and supination sensing device according to any one of claims 1-9.

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