技术领域Technical field
本发明属于康复工程技术领域，具体涉及一种基于聚焦超声的力触觉刺激系统，还涉及一种基于聚焦超声的力触觉刺激方法。The present invention belongs to the technical field of rehabilitation engineering, and in particular relates to a force tactile stimulation system based on focused ultrasound, and also relates to a force tactile stimulation method based on focused ultrasound.
背景技术Background technique
皮肤是身体的最大感觉器官，皮肤中有多种感觉受体，包括梅克尔细胞、末梢神经纤维、皮下组织和毛囊等，它们对不同的触觉刺激非常敏感。当皮肤受到触觉刺激时，感觉神经末梢的受体将这些刺激转化为神经冲动。这些神经冲动通过感觉神经纤维传导至中枢神经系统，其中脊髓在初级的信息处理中起着关键作用，负责基本的感觉信息的传递和初步加工。随后，这些信号继续传送到大脑皮层的不同区域，如体感皮层，用于进一步的感觉加工和感知。进一步地，感觉信息在大脑中经过多层次的加工和整合，以产生有关触觉的知觉体验，包括感觉信息的整合，用于确定刺激的特性，如形状、硬度、温度和纹理等。最终，触觉信息被大脑用来识别物体、感知外部环境并引导相应的反应。例如抓握、触摸或避免刺激。The skin is the largest sensory organ of the body. There are a variety of sensory receptors in the skin, including Merkel cells, peripheral nerve fibers, subcutaneous tissue and hair follicles, etc., which are very sensitive to different tactile stimuli. When the skin is stimulated by touch, receptors on the sensory nerve endings convert these stimuli into nerve impulses. These nerve impulses are conducted to the central nervous system through sensory nerve fibers, where the spinal cord plays a key role in primary information processing and is responsible for the transmission and preliminary processing of basic sensory information. These signals then continue to different areas of the cerebral cortex, such as the somatosensory cortex, for further sensory processing and perception. Furthermore, sensory information is processed and integrated at multiple levels in the brain to produce a perceptual experience related to touch, including the integration of sensory information to determine the characteristics of the stimulus, such as shape, hardness, temperature, and texture. Ultimately, tactile information is used by the brain to identify objects, sense the external environment, and guide appropriate responses. Such as grasping, touching, or avoiding stimulation.
对于中枢神经系统疾病如卒中、脑外伤、脊髓损伤等导致的触觉减弱、触觉缺失等典型的感觉功能障碍，触觉刺激是临床上被用来恢复患者感觉功能的治疗方法之一。临床上，主要通过物理、机械或电的方式传达压力、振动、温度等触觉感觉给人体的皮肤或其他感觉器官，以提高患者对环境的信息感知与精细动作控制，进而高效恢复人体感觉功能。此外，触觉刺激还在虚拟现实、机器人控制、远程遥操作等人机交互领域得到了广泛研究和应用。For typical sensory dysfunctions such as weakened touch and loss of touch caused by central nervous system diseases such as stroke, brain trauma, spinal cord injury, etc., tactile stimulation is one of the treatments used clinically to restore patients' sensory functions. Clinically, it mainly conveys tactile sensations such as pressure, vibration, temperature, etc. to the human body's skin or other sensory organs through physical, mechanical or electrical means to improve the patient's information perception of the environment and fine movement control, thereby effectively restoring the human body's sensory functions. In addition, tactile stimulation has been widely researched and applied in human-computer interaction fields such as virtual reality, robot control, and remote operation.
当前，通过物理刺激外周实现人体触觉功能重建的方法主要分为两种：机械刺激与电刺激。机械刺激包括震动刺激和压力刺激，震动刺激通过采用微型直流电机、音圈或螺线管等作为刺激单元(振子)，通过控制振子产生机械震动，将低频的震动刺激传递给使用者皮肤；而压力刺激则是通过控制压电材料、气体或液体囊腔产生机械位移，探头垂直于皮肤，从而向使用者皮肤施加压力刺激。香港理工大学研究团队利用纺织品在手臂摩挲，以探究机械刺激在大脑皮层的响应，他们认为机械刺激可显著激活大脑感觉运动区域。香港城市大学成功研发基于机械刺激触觉反馈的新型触觉传感器阵列机械手，通过压力感受器的触觉反馈提高了机械手的控制速度与自由度。电刺激利用电流刺激神经元，触发动作电位传播，以激活感觉运动通路而刺激肌肉收缩，从而导致周围感觉运动神经去极化，实现感觉运动功能修复的目的。近年来，随着柔性传感技术的蓬勃发展，越来越多的证据表明，非侵入性的电刺激疗法显著改善感觉障碍患者的触觉功能，并对减轻疼痛、痉挛以及增强肌肉运动功能具有积极作用。北卡莱罗纳大学研究团队通过给分布在正中神经和尺神经附近的电极阵列施加电刺激，成功诱发了前臂截肢者多个幻指区域的多种触觉。约翰霍普金斯大学研究团队发现基于电刺激的触觉反馈可以改变截肢者躯体感觉皮层的动态脑连接，提高患侧肢体感受能力。上海交通大学研究团队在脑卒中后的运动功能康复中，发现基于电刺激的触觉反馈对于提高偏瘫患者患侧肢体控制能力、促进脑功能重塑也发挥着重要的作用。Currently, there are two main methods for reconstructing human tactile function through physical stimulation of the periphery: mechanical stimulation and electrical stimulation. Mechanical stimulation includes vibration stimulation and pressure stimulation. Vibration stimulation uses a micro DC motor, voice coil or solenoid as the stimulation unit (vibrator), and controls the vibrator to generate mechanical vibration to deliver low-frequency vibration stimulation to the user's skin; Pressure stimulation is to exert pressure stimulation on the user's skin by controlling the mechanical displacement of the piezoelectric material, gas or liquid cyst cavity, and the probe is perpendicular to the skin. A research team from the Hong Kong Polytechnic University used textiles to rub the arms to explore the response of mechanical stimulation in the cerebral cortex. They believe that mechanical stimulation can significantly activate the sensorimotor area of the brain. City University of Hong Kong has successfully developed a new tactile sensor array manipulator based on mechanical stimulation tactile feedback, which improves the control speed and freedom of the manipulator through tactile feedback from pressure sensors. Electrical stimulation uses electric current to stimulate neurons and trigger action potential propagation to activate sensorimotor pathways and stimulate muscle contraction, thereby leading to depolarization of peripheral sensorimotor nerves and achieving the purpose of restoring sensorimotor functions. In recent years, with the vigorous development of flexible sensing technology, more and more evidence shows that non-invasive electrical stimulation therapy can significantly improve the tactile function of patients with sensory disorders, and has positive effects on reducing pain, spasm and enhancing muscle movement function. effect. A research team from the University of North Carolina successfully induced multiple tactile sensations in multiple phantom finger areas in forearm amputees by applying electrical stimulation to an electrode array distributed near the median and ulnar nerves. The Johns Hopkins University research team found that tactile feedback based on electrical stimulation can change the dynamic brain connections of the somatosensory cortex of amputees and improve the sensory ability of the affected limb. In the rehabilitation of motor functions after stroke, a research team from Shanghai Jiao Tong University found that tactile feedback based on electrical stimulation also plays an important role in improving the control ability of the affected limbs of hemiplegic patients and promoting brain function remodeling.
机械刺激用于触觉重建存在的主要问题是机械振子往往需要一定的空间体积，导致机械刺激空间选择性较低，难以实现对特定区域的精确刺激，在一些需要高度局部化的应用中限制了其有效性。另外，传统机械刺激方法通常只提供有限的信息模态，主要以震动或压力为主，无法提供更多复杂的触觉信息，例如温度、形状等，限制了机械刺激在模拟多样化触觉反馈方面的应用。电刺激是用于触觉重建具有简单易行、轻巧简便、能量转换效率高、便于程序控制等优点等优势，但难以提供持续稳定的触觉刺激。特别是，在长时间相同位置或高强度刺激下，可能导致感觉敏锐度降低，引发人体感觉适应现象。这种适应程度不仅与刺激强度相关，还与刺激频率、刺激时长有关。简言之，电触觉并非一成不变，其诱发的感觉强度可能随着刺激时间的延长而减弱。The main problem with using mechanical stimulation for tactile reconstruction is that mechanical vibrators often require a certain spatial volume, resulting in low spatial selectivity of mechanical stimulation and difficulty in achieving precise stimulation of specific areas, which limits its use in some applications that require a high degree of localization. effectiveness. In addition, traditional mechanical stimulation methods usually only provide limited information modalities, mainly vibration or pressure, and cannot provide more complex tactile information, such as temperature, shape, etc., which limits the use of mechanical stimulation in simulating diverse tactile feedback. application. Electrical stimulation is used for tactile reconstruction and has the advantages of simplicity, lightness, high energy conversion efficiency, and easy program control, but it is difficult to provide continuous and stable tactile stimulation. In particular, being in the same position for a long time or under high-intensity stimulation may lead to a decrease in sensory acuity and trigger the phenomenon of human sensory adaptation. This degree of adaptation is not only related to the intensity of stimulation, but also to the frequency and duration of stimulation. In short, electrotactile sensation is not static, and the intensity of the sensations it evokes may weaken with prolonged stimulation.
针对机械刺激空间选择性低、反馈信息模态单一以及持续电刺激易引起人体感觉适应等问题，提供无创、空间选择性高且稳定的多模态力触觉刺激方法是当前重要的技术需求。聚焦超声刺激是基于声学机械效应，以特定频率和能量发射超声波(>20kHz)，在生物组织中传递机械力，从而实现非侵入刺激的新型神经调控方法。低频聚焦超声作为调节神经组织活动的新兴技术，近年来被越来越多地应用于中枢神经调控。我们的初步研究发现，相较于机械刺激，低强度聚焦超声刺激可实现高空间选择性的无创触觉刺激，具有响应速度快、参数调节范围宽、刺激深度可控等优点。此外，聚焦超声的生物作用原理与电刺激不同，可带来更稳定的力触觉重建效果。因此，本专利提出采用低强度聚焦超声技术，搭建超声刺激系统，通过选择换能器基频，调节脉冲重复频率、声压组合等，来实现不同类型、不同强度、长期稳定的力触觉重建。In view of the problems such as low spatial selectivity of mechanical stimulation, single feedback information modality, and continuous electrical stimulation that easily causes human body sensory adaptation, providing a non-invasive, highly spatially selective and stable multi-modal force-tactile stimulation method is an important current technical need. Focused ultrasound stimulation is a new neuromodulation method based on acoustic-mechanical effects that emits ultrasonic waves (>20kHz) at a specific frequency and energy to transmit mechanical force in biological tissues, thereby achieving non-invasive stimulation. As an emerging technology for regulating the activity of neural tissue, low-frequency focused ultrasound has been increasingly used in central nervous system regulation in recent years. Our preliminary research found that compared with mechanical stimulation, low-intensity focused ultrasound stimulation can achieve highly spatially selective non-invasive tactile stimulation, with the advantages of fast response speed, wide parameter adjustment range, and controllable stimulation depth. In addition, the biological action principle of focused ultrasound is different from that of electrical stimulation, which can bring about a more stable force-tactile reconstruction effect. Therefore, this patent proposes to use low-intensity focused ultrasound technology to build an ultrasonic stimulation system. By selecting the fundamental frequency of the transducer, adjusting the pulse repetition frequency, sound pressure combination, etc., it can achieve different types, different intensities, and long-term stable force-tactile reconstruction.
发明内容Contents of the invention
本发明第一目的是提供一种基于聚焦超声的力触觉刺激系统，解决现有技术中机械刺激空间选择性、精确性低，电刺激长时间使用会导致感觉敏锐度降低，易引起人体不适的不足。The first object of the present invention is to provide a force-tactile stimulation system based on focused ultrasound to solve the problems in the existing technology of low spatial selectivity and accuracy of mechanical stimulation, and long-term use of electrical stimulation will lead to reduced sensory acuity and easily cause human discomfort. insufficient.
本发明第二目的是提供一种基于聚焦超声的力触觉刺激方法。The second object of the present invention is to provide a force tactile stimulation method based on focused ultrasound.
为实现上述目的，本发明采用以下技术方案：In order to achieve the above objects, the present invention adopts the following technical solutions:
一种基于聚焦超声的力触觉刺激系统，包括：A force tactile stimulation system based on focused ultrasound, comprising:
超声波形产生模块，用于产生超声波形；An ultrasonic wave waveform generating module, used for generating an ultrasonic wave waveform;
功率放大模块，与所述超声波形产生模块连接，对超声波形进行信号转换传送；A power amplification module, connected to the ultrasonic waveform generation module, performs signal conversion and transmission of the ultrasonic waveform;
刺激模块，与所述功率放大模块连接，接收功率放大模块的信号，对外输出刺激。The stimulation module is connected to the power amplification module, receives the signal from the power amplification module, and outputs stimulation to the outside.
本发明中，所述超声波形产生模块为双通道函数信号发生器。In the present invention, the ultrasonic waveform generation module is a dual-channel function signal generator.
进一步地，所述双通道函数信号发生器包括第一通道和第二通道；所述第一通道用于指定为波形的脉冲重复频率分量，所述第二通道用于产生刺激波形的声压；所述第一通道是第二通道的触发输入通道。Further, the dual-channel function signal generator includes a first channel and a second channel; the first channel is used to designate the pulse repetition frequency component of the waveform, and the second channel is used to generate the sound pressure of the stimulation waveform; The first channel is the trigger input channel of the second channel.
进一步地，所述超声波形为正弦波。Furthermore, the ultrasonic waveform is a sine wave.
进一步地，所述超声波形的脉冲持续时间通过调整第二通道上每个脉冲的周期数来设定；刺激持续时间通过调整第一通道上的脉冲数来设定。Furthermore, the pulse duration of the ultrasonic waveform is set by adjusting the number of cycles of each pulse on the second channel; and the stimulation duration is set by adjusting the number of pulses on the first channel.
本发明中，所述功率放大模块为功率放大器。In the present invention, the power amplification module is a power amplifier.
进一步地，所述功率放大器为线性射频放大器。Furthermore, the power amplifier is a linear radio frequency amplifier.
本发明中，所述刺激模块为超声换能器。In the present invention, the stimulation module is an ultrasonic transducer.
进一步地，所述超声还能器为磁共振兼容气体基质压电复合超声换能器，设有准直器。通过调整准直器的几何形状和位置，调节表层能量、表层声压、焦区能量及焦区声压等参数，最大程度实现聚焦点处不同基频下的刺激量匹配。Further, the ultrasonic transducer is a magnetic resonance compatible gas matrix piezoelectric composite ultrasonic transducer and is provided with a collimator. By adjusting the geometry and position of the collimator, and adjusting parameters such as surface energy, surface sound pressure, focal area energy, and focal area sound pressure, the stimulation amount matching at different fundamental frequencies at the focus point can be achieved to the greatest extent.
研究表明，基频在0.2MHz和2.67MHz之间的低频聚焦超声更容易诱发外周神经感觉，而超声换能器的基频直接影响聚焦区域大小和刺激深度。本发明中，所述超声换能器基频为0.2-2.67MHz。Studies have shown that low-frequency focused ultrasound with a fundamental frequency between 0.2MHz and 2.67MHz is more likely to induce peripheral nerve sensation, and the fundamental frequency of the ultrasound transducer directly affects the size of the focus area and the depth of stimulation. In the present invention, the fundamental frequency of the ultrasonic transducer is 0.2-2.67MHz.
进一步地，所述超声换能器基频为0.2-1MHz。Furthermore, the fundamental frequency of the ultrasonic transducer is 0.2-1 MHz.
一种基于聚焦超声的力触觉刺激方法，包括以下步骤：A method for force tactile stimulation based on focused ultrasound comprises the following steps:
选择刺激位点作为目标感觉区域，评估目标感觉区域的感觉功能，确定目标刺激区域；将目标刺激区域放置于力触觉刺激系统的刺激模块上方，选择安全刺激参数作用于刺激位点，进行力触觉刺激。Select the stimulation site as the target sensory area, evaluate the sensory function of the target sensory area, and determine the target stimulation area; place the target stimulation area above the stimulation module of the force-tactile stimulation system, select safe stimulation parameters to act on the stimulation site, and perform force-tactile stimulation. Stimulate.
本发明中，所述刺激位点包括前臂对应正中神经的曲腕肌、手掌的拇指掌肌及食指、中指与拇指。In the present invention, the stimulation sites include the flexor carpi muscle of the forearm corresponding to the median nerve, the thumb palmar muscle of the palm, and the index finger, middle finger and thumb.
本发明中，通过毛刷、音叉皮肤震动觉定性检查等方法评估目标感觉区域的感觉功能。In the present invention, the sensory function of the target sensory area is evaluated through methods such as qualitative examination of skin vibration sensation using brushes and tuning forks.
进一步地，所述感觉功能包括触觉、压觉、震动觉和两点辨别觉。Further, the sensory functions include touch, pressure, vibration and two-point discrimination.
本发明中，所述刺激参数包含超声换能器基频、占空比、刺激时长、脉冲重复频率、声压。In the present invention, the stimulation parameters include the fundamental frequency of the ultrasonic transducer, duty cycle, stimulation duration, pulse repetition frequency, and sound pressure.
进一步地，所述刺激参数为声压与脉冲重复频率、占空比的组合。通过测试发现，脉冲重复频率与声压、占空比是影响声场分布的重要因素。脉冲重复频率与声压直接是影响感觉类型与强度的关键参数，调试不同的脉冲重复频率将产生不同的力触觉，而不同的声压则产生不同的力触觉强度。因此将这两个参数进行组合测试，以诱发不同感觉类型下不同强度的力触觉。首先将该两个参数进行组合，使用经典的两阶段方法，在确定的基准刺激水平下，让受试者适应该刺激水平。随后，在适应阶段后，引入变化较小或较大的刺激，要求受试者判断这一变化是否可察觉。记录受试者的反应，包括他们的判断是否感觉到变化，以及如果感觉到，确认变化的程度。Further, the stimulation parameter is a combination of sound pressure, pulse repetition frequency, and duty cycle. Through testing, it was found that pulse repetition frequency, sound pressure, and duty cycle are important factors that affect the sound field distribution. Pulse repetition frequency and sound pressure are key parameters that directly affect the type and intensity of sensation. Adjusting different pulse repetition frequencies will produce different force tactile sensations, while different sound pressures will produce different force tactile sensations. These two parameters were therefore tested in combination to induce different intensities of force touch for different sensory types. The two parameters are first combined and the subject is allowed to adapt to the stimulation level at a determined baseline stimulation level using a classic two-stage method. Subsequently, after an adaptation phase, a stimulus with a smaller or larger change was introduced and subjects were asked to judge whether the change was perceptible. The subjects' responses were recorded, including whether a change was perceived in their judgment and, if so, the extent of the confirmed change.
进一步地，根据声压与脉冲重复频率的组合，得到了四种力触觉，分别是弱震动觉、强震动觉、弱触压觉和强触压觉。Furthermore, based on the combination of sound pressure and pulse repetition frequency, four kinds of force tactile sensations are obtained, namely weak vibration sensation, strong vibration sensation, weak touch pressure sensation and strong touch pressure sensation.
进一步地，所述脉冲重复频率为8Hz-86 Hz，所述声压为250mvpp-700mvpp。Further, the pulse repetition frequency is 8Hz-86 Hz, and the sound pressure is 250mvpp-700mvpp.
进一步地，所述弱震动觉脉冲重复频率为8-12Hz,声压为250-450mvpp；所述强震动觉脉冲重复频率为18-26Hz,声压为500-700mvpp；所述弱触压觉脉冲重复频率为46-56Hz,声压为250-450mvpp；所述强触压觉脉冲重复频率为72-86Hz,声压为500-700mvpp。Further, the weak vibration pulse repetition frequency is 8-12Hz, and the sound pressure is 250-450mvpp; the strong vibration pulse repetition frequency is 18-26Hz, and the sound pressure is 500-700mvpp; the weak touch pressure pulse The repetition frequency is 46-56Hz, and the sound pressure is 250-450mvpp; the repetition frequency of the strong touch pressure pulse is 72-86Hz, and the sound pressure is 500-700mvpp.
进一步地，所述弱震动觉PRF为10Hz,350mvpp；所述强震动觉为20Hz,550mvpp；所述弱触压觉为50Hz,350mvpp；所述强触压觉为80Hz,550mvpp。Further, the PRF of the weak vibration sense is 10Hz, 350mvpp; the strong vibration sense is 20Hz, 550mvpp; the weak touch pressure sense is 50Hz, 350mvpp; and the strong touch pressure sense is 80Hz, 550mvpp.
本发明中,所述占空比为1％-3％。In the present invention, the duty cycle is 1%-3%.
本发明具有以下有益效果：The invention has the following beneficial effects:
(1)本发明基于聚焦超声的力触觉刺激系统，利用聚焦超声的机械效应，作用于皮肤具有无创、聚焦与深度穿透的特点，同时，可避免感觉敏锐度随着刺激时长或次数的增加而下降的问题。(1) The force-tactile stimulation system of the present invention based on focused ultrasound uses the mechanical effect of focused ultrasound to act on the skin with the characteristics of non-invasive, focused and deep penetration. At the same time, it can avoid the increase in sensory acuity with the duration or frequency of stimulation. And the problem of decline.
(2)本发明结合生理物理指标最小可察觉差异与韦伯分数，通过精心设计和精确控制超声刺激的脉冲重复频率和声压参数，成功实现了4种高度辨别的力触觉感觉，分别对应于“震动”的不同强弱程度和“触压”的强度变化，每种触觉均能长期稳定诱发。这一创新性研究为触觉感知领域提供了重要的实验基础，不仅深化了对触觉感觉的理解，还为未来感知研究和工程应用提供了有力的指导和启发。(2) The present invention combines the minimum perceptible difference in physiological and physical indicators and the Weber fraction, and through careful design and precise control of the pulse repetition frequency and sound pressure parameters of ultrasonic stimulation, successfully achieves four highly differentiated force-tactile sensations, respectively corresponding to " With different intensity levels of "vibration" and changes in the intensity of "touch pressure", each tactile sensation can be induced stably for a long time. This innovative research provides an important experimental basis for the field of tactile perception. It not only deepens the understanding of tactile sensation, but also provides powerful guidance and inspiration for future perception research and engineering applications.
(3)本发明采用心理物理学实验设计方法，设计短时辨别刺激类型的主观实验，统计超声触觉刺激的准确性，根据每个试次的结果，通过分别统计4次测试的识别错误的个数，进一步验证实验结果的准确性与稳定性。(3) The present invention adopts a psychophysical experimental design method to design a subjective experiment for short-term discrimination of stimulus types, and statistically analyzes the accuracy of ultrasonic tactile stimulation. Based on the results of each trial, the accuracy and stability of the experimental results are further verified by separately counting the number of recognition errors in four tests.
附图说明Description of drawings
下面结合说明书附图和具体实施方式对本发明的技术方案做进一步说明。The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.
图1为本发明所搭建的超声刺激系统结构示意图；Figure 1 is a schematic structural diagram of the ultrasonic stimulation system built by the present invention;
图2为选择脉冲重复频率的最小可察觉差异指标分析图；FIG2 is a diagram showing the minimum perceptible difference index analysis for selecting a pulse repetition frequency;
图3为选择声压的最小可察觉差异指标分析图；Figure 3 is an analysis chart of the minimum perceptible difference index for selecting sound pressure;
图4为超声刺激参数组合图；Figure 4 is a combination diagram of ultrasonic stimulation parameters;
图5为主观测试准确率(ES为电刺激，其它为不同基频的超声刺激)；Figure 5 shows the subjective test accuracy (ES is electrical stimulation, and the others are ultrasound stimulation at different fundamental frequencies);
图6为主观测试中不同试次的识别错误数量；Figure 6 shows the number of recognition errors in different trials in the subjective test;
图中附图标记如下：1、超声波形产生模块；2、功率放大模块；3、刺激模块；4、第一通道；5、第二通道。The reference numbers in the figure are as follows: 1. Ultrasonic waveform generation module; 2. Power amplification module; 3. Stimulation module; 4. First channel; 5. Second channel.
具体实施方式Detailed ways
本发明首先构建了一个基于聚焦超声的力触觉刺激系统，该系统能完成超声波的产生与输送。此外，本发明提出一种基于聚焦超声的力触觉刺激方法，基于基于聚焦超声的力触觉刺激系统，优化超声换能器基频选择，通过调节多种超声刺激参数来重建不同强度与类型力触觉。该方法通过调节脉冲重复频率与声压来进行力触觉刺激，结合2个心理物理指标：最小可察觉差异(Just Noticeable Difference,JND)与韦伯分数(Weber Factor,WF)，作为在不同感知任务中的敏感性和判别能力，以寻找最优刺激参数组合，实现不同类型的力触觉在两种强度下的长期稳定诱发方法。The present invention first constructs a force tactile stimulation system based on focused ultrasound, which can complete the generation and transmission of ultrasonic waves. In addition, the present invention proposes a force tactile stimulation method based on focused ultrasound, which optimizes the fundamental frequency selection of the ultrasonic transducer based on the force tactile stimulation system based on focused ultrasound, and reconstructs force tactile sensations of different intensities and types by adjusting a variety of ultrasonic stimulation parameters. This method performs force tactile stimulation by adjusting the pulse repetition frequency and sound pressure, and combines two psychophysical indicators: Just Noticeable Difference (JND) and Weber Factor (WF) as the sensitivity and discrimination ability in different perceptual tasks, in order to find the optimal combination of stimulation parameters, and realize a long-term stable induction method of different types of force tactile sensations at two intensities.
实施例1Example 1
如图1所示基于聚焦超声的力触觉刺激系统，包括：As shown in Figure 1, the force-tactile stimulation system based on focused ultrasound includes:
超声波形产生模块1，用于产生超声波形；Ultrasonic waveform generation module 1, used to generate ultrasonic waveforms;
功率放大模块2，与所述超声波形产生模块1连接，对超声波形进行信号转换传送；The power amplification module 2 is connected to the ultrasonic waveform generation module 1 to perform signal conversion and transmission of the ultrasonic waveform;
刺激模块3，与所述功率放大模块2连接，接收功率放大模块2的信号，对外输出刺激。The stimulation module 3 is connected to the power amplification module 2, receives the signal from the power amplification module 2, and outputs stimulation to the outside.
本实施例中，超声波形产生模块1为双通道函数信号发生器。双通道函数信号发生器包括第一通道4和第二通道5；第一通道4用于指定为波形的脉冲重复频率分量，第二通道5用于产生刺激波形的声压；第一通道4是第二通道5的触发输入通道。超声波形为正弦波。超声波形的脉冲持续时间通过调整第二通道5上每个脉冲的周期数来设定；刺激持续时间通过调整第一通道4上的脉冲数来设定。In this embodiment, the ultrasonic waveform generating module 1 is a dual-channel function signal generator. The dual-channel function signal generator includes a first channel 4 and a second channel 5; the first channel 4 is used to specify the pulse repetition frequency component of the waveform, and the second channel 5 is used to generate the sound pressure of the stimulation waveform; the first channel 4 is the trigger input channel of the second channel 5. The ultrasonic waveform is a sine wave. The pulse duration of the ultrasonic waveform is set by adjusting the number of cycles of each pulse on the second channel 5; the stimulation duration is set by adjusting the number of pulses on the first channel 4.
功率放大模块2为功率放大器，功率放大器为线性射频放大器。刺激模块3为超声换能器。本实施例中超声换能器为磁共振兼容气体基质压电复合超声换能器，设有准直器(图中未示出)。通过调整准直器的几何形状和位置，调节表层能量、表层声压、焦区能量及焦区声压等参数，最大程度实现聚焦点处不同基频下的刺激量匹配。超声换能器基频为0.2-2.67MHz。研究表明，基频在0.2MHz和2.67MHz之间的低频聚焦超声更容易诱发外周神经感觉，而超声换能器的基频直接影响聚焦区域大小和刺激深度。更优选地，超声换能器基频为0.2-1MHz。The power amplifier module 2 is a power amplifier, and the power amplifier is a linear radio frequency amplifier. Stimulation module 3 is an ultrasound transducer. In this embodiment, the ultrasonic transducer is a magnetic resonance compatible gas matrix piezoelectric composite ultrasonic transducer and is provided with a collimator (not shown in the figure). By adjusting the geometry and position of the collimator, and adjusting parameters such as surface energy, surface sound pressure, focal area energy, and focal area sound pressure, the stimulation amount matching at different fundamental frequencies at the focus point can be achieved to the greatest extent. The fundamental frequency of the ultrasonic transducer is 0.2-2.67MHz. Studies have shown that low-frequency focused ultrasound with a fundamental frequency between 0.2MHz and 2.67MHz is more likely to induce peripheral nerve sensation, and the fundamental frequency of the ultrasound transducer directly affects the size of the focus area and the depth of stimulation. More preferably, the fundamental frequency of the ultrasonic transducer is 0.2-1MHz.
实施例2Example 2
一种基于聚焦超声的力触觉刺激方法，包括以下步骤：A force-tactile stimulation method based on focused ultrasound includes the following steps:
选择刺激位点作为目标感觉区域，评估目标感觉区域的感觉功能，确定目标刺激区域；将目标刺激区域放置于刺激模块上方，选择安全刺激参数作用于刺激位点，进行力触觉刺激。Select the stimulation site as the target sensory area, evaluate the sensory function of the target sensory area, and determine the target stimulation area; place the target stimulation area above the stimulation module, select safe stimulation parameters to act on the stimulation site, and perform force-tactile stimulation.
具体过程如下：The specific process is as follows:
针对超声刺激的无创、聚焦、深度穿透的特点，分别选择前臂对应正中神经的曲腕肌、手掌的拇指掌肌及食指、中指与拇指作为刺激位点。将以上刺激位点分别作为目标感觉区域(患者的患侧作为刺激区域)，首先通过毛刷、音叉皮肤震动觉定性检查等方法评估目标感觉区域的触觉、压觉、震动觉、两点辨别觉等感觉功能，确定目标刺激区域。随后将目标刺激区域放置于力触觉刺激系统刺激模块超声换能器上方所覆盖的薄膜，选择安全刺激参数作用于刺激位点，进行力触觉刺激。其中，刺激参数包含超声换能器基频、占空比、刺激时长、脉冲重复频率、声压。最佳刺激位点根据受试者主观感受确定。In view of the characteristics of non-invasive, focused and deep penetration of ultrasound stimulation, the flexor carpi muscle of the forearm corresponding to the median nerve, the thumb palmar muscle of the palm, the index finger, middle finger and thumb were selected as stimulation sites. The above stimulation sites are used as target sensory areas (the affected side of the patient is used as the stimulation area). First, the touch, pressure, vibration, and two-point discrimination of the target sensory area are evaluated through methods such as hair brushes and tuning fork skin vibration sensation qualitative tests. and other sensory functions to determine the target stimulation area. Then place the target stimulation area on the film covered above the ultrasonic transducer of the stimulation module of the force tactile stimulation system, select safe stimulation parameters to act on the stimulation site, and perform force tactile stimulation. Among them, the stimulation parameters include the fundamental frequency of the ultrasonic transducer, duty cycle, stimulation duration, pulse repetition frequency, and sound pressure. The optimal stimulation site is determined based on the subjective feelings of the subject.
为触觉刺激设计提供科学依据，将JND(最小可察觉差异)和WF(韦伯分数)这两个心理物理指标结合，可以更准确地确定触觉刺激的感知辨别度和舒适度。引起超声刺激诱发感觉变化的参数包括超声换能器基频、占空比、刺激时长、脉冲重复频率、声压等。其中脉冲重复频率与声压、占空比是影响声场分布的重要因素。通过测试发现，脉冲重复频率与声压直接是影响感觉类型与强度的关键参数，调试不同的脉冲重复频率将产生不同的力触觉，而不同的声压则产生不同的力触觉强度。因此将这两个参数进行组合测试，以诱发不同感觉类型下不同强度的力触觉。首先将该两个参数进行组合，得到四种力触觉，分别是弱震动觉、强震动觉、弱触压觉和强触压觉，使用经典的两阶段方法，在确定的基准刺激水平下，让受试者适应该刺激水平。随后，在适应阶段后，引入变化较小或较大的刺激，要求受试者判断这一变化是否可察觉。记录受试者的反应，包括他们的判断是否感觉到变化，以及如果感觉到，确认变化的程度。通过多次实验，收集足够的数据计算JND，即可辨别性阈值。使用统计分析方法对JND数据进行分析，确定在不同触觉刺激参数下的感知阈值。最终将JND达到75％以上的参数范围纳入可实验范围。此外，引导受试者体验各种触觉刺激，并要求他们对每种刺激的舒适度进行主观评价。使用标准化的舒适度评估工具，如视觉模拟量表，确保评价结果的客观性。记录受试者的舒适度评分，并询问他们在不同刺激条件下的感受。进行足够的实验次数，获取可靠的舒适度数据。得到脉冲重复频率、声压的JND图，见图2、图3。根据以上参数的选择，最终确定四种力触觉(包括弱、强)的择优参数范围如表1所示和最优参数如图4。To provide a scientific basis for the design of tactile stimulation, the combination of the two psychophysical indicators, JND (just noticeable difference) and WF (Weber fraction), can more accurately determine the perceptual discrimination and comfort of tactile stimulation. The parameters that cause the change of sensation induced by ultrasonic stimulation include the fundamental frequency of the ultrasonic transducer, duty cycle, stimulation duration, pulse repetition frequency, sound pressure, etc. Among them, pulse repetition frequency, sound pressure and duty cycle are important factors affecting the distribution of the sound field. Through testing, it was found that pulse repetition frequency and sound pressure are directly the key parameters affecting the type and intensity of sensation. Debugging different pulse repetition frequencies will produce different force tactile sensations, while different sound pressures will produce different force tactile intensities. Therefore, these two parameters are combined and tested to induce force tactile sensations of different intensities under different sensory types. First, the two parameters are combined to obtain four types of force tactile sensations, namely weak vibration sensation, strong vibration sensation, weak touch pressure sensation and strong touch pressure sensation. Using the classic two-stage method, the subjects are allowed to adapt to the stimulation level under a determined baseline stimulation level. Subsequently, after the adaptation stage, a stimulus with a smaller or larger change is introduced, and the subjects are asked to judge whether the change is perceptible. Record the subjects' responses, including their judgment of whether they felt the change, and if so, the extent of the change. Through multiple experiments, collect enough data to calculate the JND, i.e., the discriminability threshold. Use statistical analysis methods to analyze the JND data to determine the perception threshold under different tactile stimulation parameters. Finally, the parameter range with a JND of more than 75% is included in the experimental range. In addition, guide the subjects to experience various tactile stimulations and ask them to subjectively evaluate the comfort of each stimulation. Use standardized comfort assessment tools, such as visual analog scales, to ensure the objectivity of the evaluation results. Record the subjects' comfort scores and ask them how they feel under different stimulation conditions. Conduct a sufficient number of experiments to obtain reliable comfort data. Obtain the JND diagrams of pulse repetition frequency and sound pressure, see Figures 2 and 3. Based on the selection of the above parameters, the optimal parameter ranges for the four force tactile sensations (including weak and strong) are finally determined as shown in Table 1 and the optimal parameters are shown in Figure 4.
表1不同触觉类型的刺激参数组合Table 1 Stimulation parameter combinations for different tactile types
4种力触觉最优刺激参数组合为，弱震动觉PRF(脉冲重复频率)为10Hz,声压为350mvpp；强震动觉PRF为20Hz,声压为550mvpp；弱触压觉PRF为50Hz,声压为350mvpp；强触压觉PRF为80Hz,声压为550mvpp。在上述脉冲重复频率和声压的组合中，本实施例可以选择占空比在1％-3％，可以获得更好的刺激效果。The optimal stimulation parameter combinations of the four kinds of force tactile sensation are: weak vibration sensation PRF (pulse repetition frequency) is 10Hz, sound pressure is 350mvpp; strong vibration sensation PRF is 20Hz, sound pressure is 550mvpp; weak touch pressure sensation PRF is 50Hz, sound pressure It is 350mvpp; the strong touch pressure PRF is 80Hz and the sound pressure is 550mvpp. In the above combination of pulse repetition frequency and sound pressure, in this embodiment, the duty cycle can be selected to be between 1% and 3%, so as to obtain better stimulation effect.
分别对产生的4种触觉(包括弱、强)与无刺激进行主观测试，对力触觉重建的稳定性进行评估。主观实验一共包含4个小测试，每个小测试内含4个触觉刺激与无刺激，共5种类型。其中每个刺激分别持续2s,刺激结束后休息5s。测试1与测试2，测试3与测试4均间隔5分钟，而测试2与测试3间隔20分钟。每次刺激结束后被试报告刺激类型，其中0为无刺激，1-4分别代表轻拍、重拍、轻压、重压四种触觉。最终统计被试区分不同触觉类型的准确率与每个测试下识别错误的个数如图5、图6所示。Subjective tests were conducted on the four generated tactile sensations (including weak and strong) and no stimulation to evaluate the stability of force tactile reconstruction. The subjective experiment includes a total of 4 small tests, each small test contains 4 tactile stimulation and no stimulation, a total of 5 types. Each stimulus lasted 2 s, and there was a 5 s rest after the stimulation. Test 1 and Test 2, Test 3 and Test 4 are all separated by 5 minutes, and Test 2 and Test 3 are separated by 20 minutes. After each stimulation, the subjects reported the type of stimulation, where 0 means no stimulation, and 1-4 represent the four tactile sensations of light tap, heavy tap, light pressure, and heavy pressure respectively. The final statistics on the accuracy of subjects in distinguishing different tactile types and the number of recognition errors in each test are shown in Figures 5 and 6.
本发明用16名被试在完成超声触觉刺激实验下的主观报告数据，针对每个刺激类型的结果进行分析，发现在高频高强度刺激下准确率略有下降，其它刺激参数的范围均保持高准确性。对于每个试次的结果同样证实在高频高强度的刺激参数下，识别错误个数增多，其它刺激范围的识别错误个数较低。表明超声刺激在最佳刺激范围内具有良好的稳定性，感觉敏锐度不会随着刺激次数的增加而降低。The present invention uses the subjective report data of 16 subjects who completed the ultrasonic tactile stimulation experiment, and analyzes the results of each stimulation type. It is found that the accuracy rate slightly decreases under high-frequency and high-intensity stimulation, while the range of other stimulation parameters remains unchanged. High accuracy. The results for each trial also confirmed that under high-frequency and high-intensity stimulation parameters, the number of recognition errors increased, while the number of recognition errors in other stimulation ranges was lower. It shows that ultrasonic stimulation has good stability within the optimal stimulation range, and sensory acuity will not decrease as the number of stimulations increases.
本发明主要提出一种基于聚焦超声刺激诱发不同类型和不同强度力触觉的刺激系统及刺激方法。构建了无创、精准、长期稳定的低强度聚焦超声力触觉刺激装置，通过选择最佳基频的超声换能器，优化聚焦超声刺激位置选择和定位，调整超声脉冲重复频率、声压和占空比等刺激参数组合，以诱发手指不同类型(按压和轻触)和不同强度(弱、强)的力触觉。相对于基于机械刺激和电刺激的力触觉重建方法，本发明通过声场调制，可以提高力触觉刺激的深度和空间分辨率，实现对手部无创、精准地力触觉刺激。该发明有望应用于虚拟现实、医疗模拟、康复治疗等需要力触觉反馈的人机交互场景，不仅可以提高手部任务操作的真实感，还有助于提高人机交互操作的灵巧性和稳定性。The present invention mainly proposes a stimulation system and stimulation method based on focused ultrasonic stimulation to induce different types and different intensity of force touch. A non-invasive, accurate, long-term stable low-intensity focused ultrasound force tactile stimulation device was constructed. By selecting the ultrasonic transducer with the best fundamental frequency, optimizing the location selection and positioning of the focused ultrasound stimulation, and adjusting the ultrasonic pulse repetition frequency, sound pressure and duty cycle Ratio and other stimulation parameter combinations are used to induce different types (pressing and light touching) and different intensities (weak, strong) of force touch from the fingers. Compared with force-tactile reconstruction methods based on mechanical stimulation and electrical stimulation, the present invention can improve the depth and spatial resolution of force-tactile stimulation through sound field modulation, and achieve non-invasive and precise force-tactile stimulation of the hand. This invention is expected to be used in human-computer interaction scenarios that require force tactile feedback, such as virtual reality, medical simulation, and rehabilitation therapy. It can not only improve the reality of hand task operations, but also help improve the dexterity and stability of human-computer interaction operations. .
本发明具有以下用途：The invention has the following uses:
1)感知研究：本发明可以用于深入研究人类触觉系统的感知机制。通过调整刺激参数，如频率、强度和模式，可以研究触觉感知的阈值、差异察觉能力、感知变异性等。这对于揭示触觉感知的神经生理和心理学基础非常重要。1) Perception research: The present invention can be used to conduct in-depth research on the perception mechanism of the human tactile system. By adjusting stimulation parameters such as frequency, intensity and pattern, the threshold of tactile perception, difference detection ability, perceptual variability, etc. can be studied. This is important for uncovering the neurophysiological and psychological basis of tactile perception.
2)康复医学：本发明可以用于改善康复治疗的效果。通过模拟不同的触觉刺激，可以帮助康复患者重新建立感觉和运动控制，例如，在康复治疗中帮助瘫痪患者改善肌肉功能。2) Rehabilitation medicine: The present invention can be used to improve the effect of rehabilitation therapy. By simulating different tactile stimulations, it can help rehabilitation patients to re-establish sensation and motor control, for example, helping paralyzed patients improve muscle function during rehabilitation therapy.
3)远程医疗：本发明可用于远程医疗应用，通过远程操作的方式提供触觉反馈，使医生能够感知和操作远程患者的身体。这对于远程手术和诊断有重要的潜在价值。3) Telemedicine: The present invention can be used in telemedicine applications, providing tactile feedback through remote operation, allowing doctors to sense and operate the body of remote patients. This has important potential value for remote surgery and diagnosis.
4)人机交互：在人机交互领域，本发明可以用于改进触摸屏技术和操控设备的用户体验。这可以增强用户与数字界面之间的连接，提供更生动的触觉反馈4) Human-computer interaction: In the field of human-computer interaction, the present invention can be used to improve touch screen technology and user experience of controlling devices. This enhances the connection between the user and the digital interface, providing more vivid tactile feedback
以上所揭露的仅为本发明较佳实施例而已，当然不能以此来限定本发明之权利范围，因此依本发明权利要求所作的等同变化，仍属本发明所涵盖的范围。What is disclosed above is only the preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.
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| CN202311722252.0ACN117771567A (en) | 2023-12-14 | 2023-12-14 | Force touch stimulation system and force touch stimulation method based on focused ultrasound |
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| CN202311722252.0ACN117771567A (en) | 2023-12-14 | 2023-12-14 | Force touch stimulation system and force touch stimulation method based on focused ultrasound |
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| CN117771567Atrue CN117771567A (en) | 2024-03-29 |
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| CN202311722252.0APendingCN117771567A (en) | 2023-12-14 | 2023-12-14 | Force touch stimulation system and force touch stimulation method based on focused ultrasound |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN120168872A (en)* | 2025-05-19 | 2025-06-20 | 哈尔滨工业大学(深圳)(哈尔滨工业大学深圳科技创新研究院) | A multimodal tactile feedback method and device based on focused ultrasound and electrical combined stimulation |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN120168872A (en)* | 2025-05-19 | 2025-06-20 | 哈尔滨工业大学(深圳)(哈尔滨工业大学深圳科技创新研究院) | A multimodal tactile feedback method and device based on focused ultrasound and electrical combined stimulation |
| CN120168872B (en)* | 2025-05-19 | 2025-09-12 | 哈尔滨工业大学(深圳)(哈尔滨工业大学深圳科技创新研究院) | Multi-mode tactile feedback method and device based on focused ultrasound and electrical combined stimulation |
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