Capacitive micro-displacement sensing robot foot end device and robot

Abstract

The application discloses a capacitive micro-displacement sensing robot foot end device and a robot, and belongs to the technical field of foot end sensing of a foot robot. The foot end device comprises a connecting assembly, a capacitive micro-displacement sensor and a rubber foot pad. The connecting assembly is used for connecting with the end of a robot calf. The capacitive micro-displacement sensor is embedded between the connecting assembly and the rubber foot pad. The upper plate of the capacitive micro-displacement sensor is glued and fixed with the connecting assembly. The lower plate of the capacitive micro-displacement sensor is connected with the rubber foot pad. The upper plate and the lower plate are elastically connected and sealed through a soft silicon rubber connecting sealing layer. The foot end device is used for detecting the relative micro-displacement of the foot end in X, Y and Z directions. The detection result is used for foot end contact recognition, normal compression state sensing, tangential deformation detection and sensing information for compliant control. The application integrates bearing connection, elastic grounding, sealing protection and micro-displacement sensing in the foot end, and can improve the contact sensing capability and support stability of a heavy load foot robot on a complex ground.

Description

Technical Field

[0001] This invention belongs to the field of foot-end sensing technology for legged robots, specifically relating to a capacitive micro-displacement sensing robot foot-end device and robot. Background Technology

[0002] When legged robots walk on unstructured terrain, the contact process between the foot and the ground directly affects the overall posture stability, support reliability, and movement safety. For heavy-duty legged robots, the foot not only needs to withstand large normal loads but also needs to adapt to complex contact environments such as gravel, mud, slopes, steps, metal surfaces, and slippery surfaces. Traditional foot structures typically use rubber or polyurethane pads as grounding components, mainly serving the functions of vibration damping, anti-slip, and protection, but it is difficult to directly obtain the minute compression, tangential shear, and pre-slip states inside the foot.

[0003] Existing foot-sensing solutions can be implemented using six-dimensional force sensors, joint current estimation, tactile arrays, pressure diaphragms, ground-contact switches, visual force sensing devices, or external displacement sensors. Among these, six-dimensional force sensors can acquire relatively complete force and torque information, but they are costly, require large installation space, and have high requirements for impact resistance and sealing protection; joint current estimation relies on the transmission chain model and is easily affected by reducer friction, backlash, elastic deformation, and the characteristics of the driver current loop; flexible pressure diaphragms and tactile arrays have insufficient reliability under heavy-load impact, mud, dust, and repeated shearing conditions; and external displacement sensors are easily limited by mechanical protection and wiring space.

[0004] In addition, flexible capacitor array technology typically lays out multiple unit capacitors on the pressure sensing surface to acquire pressure distribution, impact location, or tactile information. This type of approach is related to capacitive sensing, but it mainly focuses on the distribution of pressure or pressure location on the array, rather than micro-displacement coupling.

[0005] Existing technologies mainly focus on foot pressure, force detection, ground-contact switches, mechanically adaptive feet, visual multidimensional force sensing, or flexible capacitive pressure arrays. While these solutions can improve the foot sensing capabilities of robots to some extent, there is still a lack of foot sensing devices for heavy-duty legged robots that can be directly embedded in the foot bearing path while also providing sealing protection and compliant control / slip detection applications. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a capacitive micro-displacement sensing robot foot device and robot. The device integrates connecting components, a capacitive micro-displacement sensor, and a cast-molded rubber footpad into a single design, creating a synergistic structure between load-bearing, vibration damping, anti-slip, sealing protection, and micro-displacement sensing. This robot foot device can detect the relative micro-displacement of the robot foot in the X, Y, and Z directions, providing direct sensing data for contact state recognition, compliant control, slip detection, and stable support in complex terrain.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a capacitive micro-displacement sensing robot foot device for detecting the relative micro-displacement of the robot foot in the X, Y, and Z directions; the capacitive micro-displacement sensing robot foot device includes a connecting component, a capacitive micro-displacement sensor, and a rubber foot pad; the capacitive micro-displacement sensor is embedded between the connecting component and the rubber foot pad; the connecting component is connected to the end of the robot's lower leg; the rubber foot pad is formed by injection molding and is used for grounding support;

[0009] The capacitive micro-displacement sensor includes an upper electrode plate, a lower electrode plate, a soft silicone rubber connecting and sealing layer, and a capacitance detection area; wherein, the upper electrode plate is glued and fixed to the connecting assembly; the lower electrode plate is connected to the rubber foot pad; the soft silicone rubber connecting and sealing layer is disposed between the upper electrode plate and the lower electrode plate, for elastically connecting the upper electrode plate and the lower electrode plate, maintaining the initial gap between the upper electrode plate and the lower electrode plate, and sealing the capacitance detection area.

[0010] Furthermore, the connecting assembly includes a lower leg connecting portion, a sensor mounting portion, and a load-bearing transition portion located between the lower leg connecting portion and the sensor mounting portion; the lower leg connecting portion is detachably connected to the end of the robot's lower leg; the sensor mounting portion has a mounting reference surface for bonding with the upper electrode plate.

[0011] Furthermore, the load-bearing transition section is one of a conical transition structure, a stepped transition structure, a rounded corner transition structure, or a reinforcing rib transition structure; the load-bearing transition section is used to transfer the load from the end of the robot's lower leg between the lower leg connection section and the sensor mounting section.

[0012] Furthermore, the upper electrode plate is glued and fixed to the sensor mounting part by an adhesive layer; the adhesive layer is one of structural adhesive, silicone rubber adhesive, epoxy adhesive, polyurethane adhesive or elastic adhesive.

[0013] Furthermore, the soft silicone rubber connecting sealing layer is disposed in the peripheral area between the upper electrode plate and the lower electrode plate, and is glued and fixed to the upper electrode plate and the lower electrode plate.

[0014] Furthermore, the lower electrode plate is at least partially embedded in the rubber foot pad, or connected to the rubber foot pad by at least one of the following methods: gluing, injection coating, inverted fitting, through-hole gluing, and surface roughening bonding.

[0015] Furthermore, the rubber foot pad is made of one of polyurethane rubber, silicone rubber, nitrile rubber, natural rubber or composite elastomer material, and is formed by pouring and curing in a foot pad mold.

[0016] Furthermore, the rubber foot pad has a ground contact surface and an outer circumferential rounded corner transition surface; the ground contact surface is a composite contact surface composed of one or more of the following: a plane, a spherical crown surface, a micro-arc surface, and a textured plane; the outer circumferential rounded corner transition surface is used to reduce the concentration of edge stress of the rubber foot pad and improve the smoothness of transition during rolling contact.

[0017] Furthermore, the capacitive micro-displacement sensor is a four-quadrant differential capacitive micro-displacement sensor, and multiple partition electrodes are provided on the upper and / or lower electrode plates to form multiple capacitance detection partitions between the upper and lower electrode plates; wherein, the tangential displacement of the robot foot causes differential changes in capacitance in different capacitance detection partitions, and the normal displacement of the robot foot causes common-mode changes in capacitance in multiple capacitance detection partitions.

[0018] Furthermore, the capacitive micro-displacement sensor is used to detect X-direction differential capacitance, Y-direction differential capacitance, and Z-direction common-mode capacitance; wherein, the X-direction differential capacitance and the Y-direction differential capacitance are obtained based on the differential changes in capacitance in different capacitance detection zones caused by the tangential displacement of the robot's foot; the Z-direction common-mode capacitance is obtained based on the common-mode changes in capacitance in multiple capacitance detection zones caused by the normal displacement of the robot's foot.

[0019] Furthermore, the capacitive micro-displacement sensing robot foot device also includes a signal processing and control unit, which is electrically connected to the capacitive micro-displacement sensor. The signal processing and control unit is used to calculate the relative micro-displacements in the X, Y, and Z directions based on the X-direction differential capacitance, the Y-direction differential capacitance, and the Z-direction common-mode capacitance, combined with a pre-calibrated relationship, and output the calculation results to the robot controller. The pre-calibrated relationship is the pre-calibrated relationship between the capacitance signal output by the capacitive micro-displacement sensor and the relative micro-displacements in the X, Y, and Z directions.

[0020] Furthermore, the connection component is provided with a lead wire channel, through which the lead wire or flexible circuit of the capacitive micro-displacement sensor is connected to the signal processing and control unit.

[0021] Furthermore, at least one of the connecting component, the upper electrode plate, the lower electrode plate, or the rubber foot pad is provided with a limiting structure, which is used to limit the maximum relative displacement between the upper electrode plate and the lower electrode plate to prevent the capacitive micro-displacement sensor from being overloaded, collided with, or sheared.

[0022] In a second aspect, the present invention provides a robot, including a body, multiple robot legs, and multiple capacitive micro-displacement sensing robot foot devices as described in the first aspect, each capacitive micro-displacement sensing robot foot device being disposed at the lower leg end of the corresponding robot leg.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. The present invention integrates the connecting components, capacitive micro-displacement sensors and injection-molded rubber foot pads into an integral structure of the robot foot end, which can obtain micro-displacement information of the inside of the foot end in the X, Y and Z directions without significantly increasing the external volume of the robot foot end.

[0025] 2. The upper electrode plate is glued and fixed to the connecting assembly, and the lower electrode plate is connected to the rubber foot pad, so that the capacitive micro-displacement sensor is directly located between the load path at the end of the robot's lower leg and the ground deformation path of the rubber foot pad, which can more directly reflect the micro-deformation before compression, shearing and sliding of the foot end.

[0026] 3. The upper and lower electrode plates are connected and sealed with soft silicone rubber, which can simultaneously achieve elastic reset, gap maintenance, sealing protection and mechanical buffering, reducing the impact of mud, dust, impact and lateral shear on capacitive micro-displacement sensors.

[0027] 4. The rubber foot pads are injection molded, which can form a stable composite connection with the lower electrode plate, avoiding the problems of easy tearing, loosening or local stress concentration of traditional screw-clamped rubber parts.

[0028] 5. The capacitive micro-displacement sensing robot foot end effector can output relative micro-displacements in the X, Y, and Z directions, providing richer contact observations for compliant control than a single contact switch, a single normal pressure, or indirect joint side estimation.

[0029] 6. By identifying slippage trends through tangential relative micro-displacement and its rate of change, changes in the viscous / slippage state between the robot's foot and the ground can be detected before obvious slippage occurs, thus improving the stability of walking on complex terrain.

[0030] 7. Compared with visual foot-end sensing or external displacement detection, the sensing structure of the present invention is located inside the robot's foot end, which facilitates sealing, protection and wiring, and is suitable for long-term use of heavy-duty legged robots in muddy, dusty and impact environments. Attached Figure Description

[0031] Figure 1 This is a cross-sectional structural diagram of the capacitive micro-displacement sensing robot foot device according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of the partitioned electrodes and the triaxial relative micro-displacement detection principle of the capacitive micro-displacement sensor according to an embodiment of the present invention.

[0033] The attached figures are labeled as follows:

[0034] 1-Connecting assembly; 11-Lower leg connecting part; 12-Bearing transition part; 13-Sensor mounting part; 2-Capacitive micro-displacement sensor; 21-Upper electrode plate; 22-Lower electrode plate; 23-Soft silicone rubber connecting sealing layer; 24-Capacitive detection area; 3-Rubber foot pad; 31-Pouring rubber body; 32-Grounding contact surface; 33-Outer peripheral rounded corner transition surface; 4-Adhesive layer; 5-Signal processing and control unit. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0037] The terms “first”, “second”, etc., are used to distinguish similar objects, not to describe or indicate a specific order or sequence.

[0038] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0039] Furthermore, to better illustrate the present invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In some instances, methods, means, elements, and circuits well known to those skilled in the art have not been described in detail in order to highlight the spirit of the invention.

[0040] Figure 1This is a cross-sectional structural diagram of the capacitive micro-displacement sensing robot foot device according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the partitioned electrodes and the triaxial relative micro-displacement detection principle of the capacitive micro-displacement sensor according to an embodiment of the present invention.

[0041] like Figure 1 As shown, the robot foot device provided in this embodiment of the invention mainly consists of three structural units: a connecting component 1, a capacitive micro-displacement sensor 2, and a rubber foot pad 3. The connecting component 1 is located at the top, connecting to the end of the robot's lower leg and transmitting the robot's leg load downwards; the capacitive micro-displacement sensor 2 is located in the middle, embedded between the connecting component 1 and the rubber foot pad 3, serving as a micro-displacement sensing component inside the foot; the rubber foot pad 3 is located at the bottom, serving as the direct contact component between the robot's foot and the ground, providing grounding support and undertaking functions such as cushioning, friction, anti-slip, and local deformation. This robot foot device is used to detect the relative micro-displacement of the robot's foot in the X, Y, and Z directions.

[0042] like Figure 1 and Figure 2 As shown, the connecting assembly 1 includes a lower leg connecting part 11, a load-bearing transition part 12, and a sensor mounting part 13. The capacitive micro-displacement sensor 2 includes an upper electrode plate 21, a lower electrode plate 22, a soft silicone rubber connecting sealing layer 23, and a capacitance detection area 24.

[0043] The lower leg connector 11 is detachably connected to the end of the robot's lower leg. The lower leg connector 11 can be connected to the end of the robot's lower leg using a plug-in, clamp, flange, screw, pin, or a combination thereof. A load-bearing transition section 12 is located between the lower leg connector 11 and the sensor mounting section 13, and is used to transfer the load from the end of the robot's lower leg between the two. The load-bearing transition section 12 can be one of a tapered transition structure, a stepped transition structure, a rounded corner transition structure, or a reinforcing rib transition structure. The sensor mounting section 13 is located at the lower end of the connecting assembly 1, and has a mounting reference surface for bonding with the upper electrode plate 21.

[0044] The upper electrode plate 21 is glued and fixed to the sensor mounting part 13 of the connecting assembly 1 via the adhesive layer 4. The adhesive layer 4 can be one of structural adhesive, silicone rubber adhesive, epoxy adhesive, polyurethane adhesive, elastic adhesive, or other adhesive materials that take into account both strength and cushioning performance. After the upper electrode plate 21 is glued and fixed to the connecting assembly 1, it can be synchronously subjected to force and move with the end of the robot's lower leg and the connecting assembly 1.

[0045] The lower electrode plate 22 can be at least partially embedded in the rubber foot pad 3. Alternatively, the lower electrode plate 22 can be connected to the upper surface or upper composite connection position of the rubber foot pad 3 by one or a combination of methods such as gluing, injection coating, inverted fitting, hole gluing, and surface roughening, so that the lower electrode plate 22 can reliably sense the compression deformation and tangential shear deformation of the rubber foot pad 3, and the lower electrode plate 22 can follow the ground deformation and ground action of the rubber foot pad 3.

[0046] A soft silicone rubber connecting and sealing layer 23 is disposed between the upper electrode plate 21 and the lower electrode plate 22. It can be located in the peripheral area between the upper electrode plate 21 and the lower electrode plate 22, and is bonded and fixed to them. The soft silicone rubber connecting and sealing layer 23 can be a continuous annular sealing structure, or a multi-segmented support sealing structure. It can also fill part of the capacitance detection area 24 while ensuring capacitance detection sensitivity. The functions of the soft silicone rubber connecting and sealing layer 23 include: elastically connecting the upper electrode plate 21 and the lower electrode plate 22, maintaining the initial gap between them, providing a restoring force after the external load is removed to achieve elastic reset, and sealing the capacitance detection area 24 to prevent water, mud, dust, and conductive particles from entering.

[0047] The rubber foot pad 3 is formed by injection molding. During manufacturing, the lower electrode plate 22, the lower electrode plate connector, or the lower electrode plate outer peripheral interlocking structure can be pre-placed in the foot pad mold, and then polyurethane rubber, silicone rubber, nitrile rubber, natural rubber, or composite elastomer material can be injected. After the material cures, it forms an injection rubber body 31 that is bonded, covered, interlocked, or integrally compositely connected with the lower electrode plate 22. The injection rubber body 31 can be provided with a ground contact surface 32 and an outer peripheral rounded corner transition surface 33. The ground contact surface 32 can be set as a composite contact surface composed of one or more of the following, such as a plane, a micro-arc surface, a spherical cap surface, or a textured plane, depending on the robot application scenario; the outer peripheral rounded corner transition surface 33 is used to reduce the concentration of edge stress of the rubber foot pad 3 and improve the smoothness of transition during rolling contact. As a result, the lower electrode plate 22 can stably sense the small displacement of the rubber foot pad 3 after being subjected to the ground, without sensing drift caused by loosening of the threaded fasteners or local stress concentration.

[0048] The rubber foot pads 3 are molded by injection molding, which can significantly improve the bonding reliability between the rubber foot pads 3 and the lower electrode plate 22. Compared with the method of directly pressing the rubber foot pads 3 onto the metal parts with screws, injection molding allows the rubber material to cover the outer edge, through holes, undercuts or roughened surfaces of the lower electrode plate 22 or its inserts, forming a larger bonding area and mechanical locking structure, reducing the risk of loosening, peeling and local tearing during long-term walking of heavy-duty robots.

[0049] In a preferred embodiment, the lower electrode plate 22 has multiple injection through holes or edge grooves on its outer periphery. After the injected rubber body 31 cures, it passes through the injection through holes or fills the edge grooves, thereby forming a mechanical fit. The side of the lower electrode plate 22 facing the rubber foot pad 3 can also be sandblasted, knurled, grooved, plasma treated, or coated with a primer to enhance the interfacial bonding strength between the lower electrode plate 22 and the rubber material.

[0050] The ground contact surface 32 of the rubber foot pad 3 can be selected according to the robot's application. For heavy-duty, low-speed hexapod robots, the ground contact surface 32 can be a flat or slightly curved surface to improve the static support area and anti-slip capability; for robots that need to move on uneven ground, the ground contact surface 32 can be a spherical or rounded transition surface to reduce transient impacts at the edges.

[0051] For example, at least one of the connecting component 1, the upper electrode plate 21, the lower electrode plate 22, or the rubber foot pad 3 is provided with a limiting structure, which is used to limit the maximum relative displacement between the upper electrode plate 21 and the lower electrode plate 22 to prevent the capacitive micro-displacement sensor 2 from being overloaded, collided, or sheared.

[0052] The capacitive micro-displacement sensor 2 is used to detect the X-axis differential capacitance, Y-axis differential capacitance, and Z-axis common-mode capacitance.

[0053] like Figure 2 As shown, the capacitive micro-displacement sensor 2 is preferably a four-quadrant differential capacitive micro-displacement sensor. At least one of the upper electrode plate 21 and the lower electrode plate 22 is provided with multiple partitioned electrodes, which are arranged around the center of the sensor to form multiple capacitance detection partitions between the upper electrode plate 21 and the lower electrode plate 22. When the robot foot is subjected to a normal reaction force from the ground (i.e., when the robot foot is subjected to a Z-direction normal force), the robot foot generates a normal displacement, and the rubber foot pad 3 and the lower electrode plate 22 generate a Z-direction compressive displacement relative to the connecting assembly 1 and the upper electrode plate 21. The distance between the upper electrode plate 21 and the lower electrode plate 22 changes, which causes a common-mode change in the capacitance of the multiple capacitance detection partitions. The capacitive micro-displacement sensor 2 can detect the Z-direction common-mode capacitance generated by this common-mode change. The relative micro-displacement in the Z-direction (i.e., the relative micro-displacement between the upper electrode plate 21 and the lower electrode plate 22 along the Z-direction) can be calculated based on the Z-direction common-mode capacitance.

[0054] When the robot's foot is subjected to tangential friction from the ground or is about to slip (i.e., when the robot's foot is subjected to tangential force in the X or Y direction), the robot's foot generates tangential displacement. The rubber foot pad 3 undergoes shear deformation in the X or Y direction relative to the connecting assembly 1, and the lower electrode plate 22 shifts laterally relative to the upper electrode plate 21. At this time, the capacitance in the capacitance detection zones located on both sides of the offset direction undergoes differential change. The capacitive micro-displacement sensor 2 can detect the X-direction differential capacitance generated by the differential capacitance change when the robot's foot is subjected to tangential force in the X direction, and the Y-direction differential capacitance generated by the differential capacitance change when the robot's foot is subjected to tangential force in the Y direction. Based on the X-direction differential capacitance and the Y-direction differential capacitance, the relative micro-displacement in the X and Y directions (i.e., the relative micro-displacement between the upper electrode plate 21 and the lower electrode plate 22 along the X and Y directions) can be calculated respectively.

[0055] like Figure 2 As shown, the robot foot device in this embodiment of the invention also includes a signal processing and control unit 5. The signal processing and control unit 5 is electrically connected to the capacitive micro-displacement sensor 2 and is used to excite, acquire, demodulate, temperature compensate, calibrate, and calculate the relative micro-displacement in the X, Y, and Z directions of the capacitive signal output by the capacitive micro-displacement sensor 2, and output the calculation results to the robot controller.

[0056] The signal processing and control unit 5 calculates the relative micro-displacements in the X, Y, and Z directions based on the X-direction differential capacitance, Y-direction differential capacitance, and Z-direction common-mode capacitance detected by the capacitive micro-displacement sensor 2, combined with the pre-calibrated relationship.

[0057] like Figure 2 As shown, in one embodiment, the signal processing and control unit 5 is excited by a capacitor in the lower electrode 22. Four capacitance detection zones , , , The capacitor is excited and its data is collected to obtain the capacitance generated by the four capacitance detection zones. , , , The X-direction differential capacitance can be obtained using the following formula. Y-direction differential capacitance and Z-axis common mode capacitance :

[0058] ;

[0059] ;

[0060] ;

[0061] Based on the differential capacitance in the X direction Y-direction differential capacitance and Z-axis common mode capacitance By combining the pre-calibrated relationships (i.e., the relationship between the capacitance signal output by the pre-calibrated capacitive micro-displacement sensor 2 and the relative micro-displacements in the X, Y, and Z directions), the relative micro-displacements in the X, Y, and Z directions can be calculated. The pre-calibrated relationships can be expressed in the form of calibration functions, which can be linear, polynomial, lookup table, or neural network calibration models. The pre-calibrated relationships can include X-direction calibration functions, Y-direction calibration functions, and Z-direction calibration functions, and the relative micro-displacements in the X, Y, and Z directions can be calculated using the following formulas:

[0062] ;

[0063] ;

[0064] ;

[0065] in, This represents the relative micro-displacement of the robot's foot in the X direction; X-direction calibration function, used to describe the relationship between the capacitance signal output by the capacitive micro-displacement sensor 2 and the relative micro-displacement in the X direction; This represents the relative micro-displacement of the robot's foot in the Y direction; This is the calibration function in the Y direction, used to describe the relationship between the capacitance signal output by the capacitive micro-displacement sensor 2 and the relative micro-displacement in the Y direction. This represents the relative micro-displacement of the robot's foot in the Z direction; This is the Z-direction calibration function, used to describe the relationship between the capacitance signal output by the capacitive micro-displacement sensor 2 and the relative micro-displacement in the Z direction.

[0066] To improve reliability in heavy-duty foot applications, the capacitive micro-displacement sensor 2 can be equipped with shielded electrodes, a protective ring, a cable shielding layer, a differential acquisition circuit, and a temperature compensation circuit. A lead wire channel can be provided inside or on the side of the connecting assembly 1. The leads or flexible circuit of the capacitive micro-displacement sensor 2 can be connected to the signal processing and control unit 5 via the lead wire channel. The leads of the rubber foot pad 3 can be arranged along the lead wire channel to prevent the leads from being exposed, pulled, or worn during the grounding process of the rubber foot pad 3.

[0067] The present invention also provides a robot, including a body, multiple robot legs, and multiple capacitive micro-displacement sensing robot foot devices as described above. The multiple robot legs correspond one-to-one with the multiple capacitive micro-displacement sensing robot foot devices, and each capacitive micro-displacement sensing robot foot device is disposed at the lower end of the corresponding robot leg.

[0068] During robot operation, the capacitive micro-displacement sensing robot foot device of the present invention can serve as a foot sensing unit in the robot control system, used to output relative micro-displacement information of the robot foot in the X, Y, and Z directions. This relative micro-displacement information can be used to characterize the contact state between the robot foot and the ground, the normal compression state of the rubber footpad 3, and the tangential deformation state, and can provide a sensing basis for robot leg motion control and compliance adjustment.

[0069] In one embodiment, the robot controller first reads the three-axis relative micro-displacement output by the capacitive micro-displacement sensing robot foot-end device. , , .in, Reflects the normal compression of the footpad and the contact state of the foot tip. and It reflects the tangential shear and lateral elastic deformation of the footpad. The robot controller can, according to... Determine whether the foot is in contact with the ground, whether the contact is stable, and whether the foot pad has entered an overload compression state.

[0070] The robot control system can adjust at least one of the following parameters of the robot's leg: target position, target velocity, target torque, support force distribution, stiffness parameter, or damping parameter, based on the foot contact and deformation state reflected by the relative micro-displacements of the three axes. For example, when... When the pressure increases continuously or its rate of change exceeds a preset range, the downward displacement, movement speed, or damping parameters of the robot's legs can be adjusted; when or During continuous deviation, the target position of the foot can be corrected or the tangential compliance parameters of the robot's leg can be adjusted. The above control method is only one application of the robot foot device of the present invention and does not constitute a limitation on the specific control form of the robot controller.

[0071] Foot slippage typically progresses through a process from static friction adhesion, tangential elastic deformation of the footpad, localized micro-slippage, to overall slippage. Before significant overall slippage occurs, measurable tangential micro-displacements have already occurred within the rubber footpad 3 and relative to the upper electrode plate 21 within the lower electrode plate 22. Therefore, the capacitive micro-displacement sensing robot foot device of this invention can provide sensing information for the robot control system to identify foot tangential deformation and slippage trends. When the relative micro-displacement in the Z direction indicates that the foot is in a state of pressure contact, the robot control system can determine the tangential deformation state of the foot based on the amplitude, trend, or micro-vibration characteristics of the relative micro-displacements in the X and Y directions.

[0072] In one embodiment, when the relative micro-displacement in the Z direction When the preset contact range is reached, the robot control system can determine that the foot is in a compressed contact state. In this state, the robot can determine the relative micro-displacement in the X direction. Relative micro-displacement in the Y direction Calculate the tangential displacement characterization quantity, or analyze it directly. and The amplitude, rate of change, and micro-vibration characteristics. When abnormal changes occur in the tangential displacement characterization, relative micro-displacement rate of change, or micro-vibration characteristics, and This still indicates that the foot is in a state of pressure contact, which can be considered as a tendency for tangential slippage of the foot.

[0073] The robot control system can perform corresponding motion adjustments based on the foot contact state and tangential deformation information, such as adjusting the body movement speed, foot target position, leg support state, gait parameters, or compliance parameters. The above judgment process is used to illustrate that the three-axis relative micro-displacement information output by the robot foot device of the present invention can support foot sliding state perception, without limiting specific threshold setting methods, signal processing algorithms, or robot control strategies.

[0074] Because the capacitive micro-displacement sensing robot foot device of this invention detects the relative micro-displacement inside the foot, rather than just the motor current or joint angle, it can more closely approximate the actual changes in the contact interface between the footpad and the ground. This feature is of great significance for the stable walking of heavy-duty legged robots on slippery, soft, sloping, and gravel surfaces.

[0075] In one embodiment, the capacitive micro-displacement sensing robot foot device of the present invention can be processed, assembled, and calibrated in the following manner.

[0076] First, the connecting component 1 is processed to have a lower leg connecting part 11 for connecting the end of the robot's lower leg and a sensor mounting part 13 for bonding the upper electrode plate 21. Next, the upper electrode plate 21, lower electrode plate 22, and electrode circuit of the capacitive micro-displacement sensor 2 are prepared. Then, the upper electrode plate 21 is bonded to the sensor mounting part 13 of the connecting component 1 through the adhesive layer 4. Then, a soft silicone rubber connecting sealing layer 23 is formed or bonded between the upper electrode plate 21 and the lower electrode plate 22 to maintain a predetermined initial gap between the upper electrode plate 21 and the lower electrode plate 22 and form a seal. Subsequently, the lower electrode plate 22 or its insert is placed into the foot pad mold, rubber material is poured in and cured to form a rubber foot pad 3. Finally, the pre-calibrated relationship is calibrated.

[0077] During calibration, known displacements or loads in the X, Y, and Z directions can be applied to the foot respectively, and the responses of multiple partition capacitors can be collected to establish a mapping relationship between the capacitor signals and the three-axis relative micro-displacements (i.e., pre-calibration relationship). The pre-calibration relationship can be stored in the signal processing and control unit 5 or the robot controller so that the three-axis relative micro-displacements can be output in real time during operation.

[0078] This invention can be applied to hexapod heavy-duty robots, quadrupedal mobile robots, bipedal robots, wheeled composite robots, exoskeleton support ends, bionic leg experimental platforms, and other equipment requiring foot contact sensing and compliant control. For multi-legged robots, a robot foot device provided by this invention can be installed at the end of the lower leg of each leg. The robot controller can integrate the three-axis relative micro-displacement information of each foot end to obtain the contact state, normal compression state, and tangential deformation state of each robot foot end, providing sensing information for robot posture stability, support state adjustment, slip trend recognition, and adaptation to complex terrain.

[0079] This invention constructs a three-segment integrated foot structure comprising a connecting component, a capacitive micro-displacement sensor, and a cast-molded rubber footpad. The connecting component is connected to the end of the robot's lower leg, the upper electrode plate is glued to the connecting component, and the lower electrode plate is connected to the rubber footpad. A soft silicone rubber sealing layer forms an elastic connection between the upper and lower electrode plates, maintaining the initial gap between them and providing a sealed protection. A four-quadrant differential capacitive micro-displacement sensor and a signal processing and control unit synchronously calculate the relative micro-displacements in the X, Y, and Z directions. These three-axis relative micro-displacements characterize the normal compression and tangential deformation states of the rubber footpad, providing a sensing basis for robot foot contact state recognition, compliance adjustment, slip trend recognition, and stable support in complex terrain. Therefore, this invention obtains information on local contact micro-displacement and shear deformation of the foot, rather than just indirect estimates based on foot pressure, ground contact switching, or information such as motor current and joint angles.

[0080] The above description is merely a preferred embodiment of the present invention. Those skilled in the art can make equivalent substitutions or improvements to the shape of the connecting components, the form of the electrode plates, the soft silicone rubber sealing method, the rubber foot pad material, the signal processing circuit, and the control algorithm without departing from the concept of the present invention; all such substitutions or improvements should fall within the protection scope of the present invention.

[0081] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0082] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. The above descriptions are exemplary and not exhaustive. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A capacitive micro-displacement sensing robot foot-end device, characterized in that, This device is used to detect the relative micro-displacement of the robot's foot in the X, Y, and Z directions. The capacitive micro-displacement sensing robot foot device includes a connecting component, a capacitive micro-displacement sensor, and a rubber foot pad. The capacitive micro-displacement sensor is embedded between the connecting component and the rubber foot pad. The connecting component is connected to the end of the robot's lower leg. The rubber foot pad is molded by injection and used for grounding support. The capacitive micro-displacement sensor includes an upper electrode plate, a lower electrode plate, a soft silicone rubber connecting and sealing layer, and a capacitance detection area; wherein, the upper electrode plate is glued and fixed to the connecting assembly; the lower electrode plate is connected to the rubber foot pad; the soft silicone rubber connecting and sealing layer is disposed between the upper electrode plate and the lower electrode plate, for elastically connecting the upper electrode plate and the lower electrode plate, maintaining the initial gap between the upper electrode plate and the lower electrode plate, and sealing the capacitance detection area.

2. The capacitive micro-displacement sensing robot foot device according to claim 1, characterized in that, The connecting assembly includes a lower leg connecting part, a sensor mounting part, and a load-bearing transition part located between the lower leg connecting part and the sensor mounting part; the lower leg connecting part is detachably connected to the end of the robot's lower leg; the sensor mounting part has a mounting reference surface for bonding with the upper electrode plate.

3. The capacitive micro-displacement sensing robot foot device according to claim 2, characterized in that, The load-bearing transition section is one of the following: a tapered transition structure, a stepped transition structure, a rounded corner transition structure, or a reinforcing rib transition structure; the load-bearing transition section is used to transfer the load from the end of the robot's lower leg between the lower leg connection section and the sensor mounting section.

4. The capacitive micro-displacement sensing robot foot device according to claim 2, characterized in that, The upper electrode plate is glued and fixed to the sensor mounting part by an adhesive layer; the adhesive layer is one of structural adhesive, silicone rubber adhesive, epoxy adhesive, polyurethane adhesive or elastic adhesive.

5. The capacitive micro-displacement sensing robot foot device according to claim 1, characterized in that, The soft silicone rubber connecting sealing layer is disposed in the peripheral area between the upper electrode plate and the lower electrode plate, and is glued and fixed to the upper electrode plate and the lower electrode plate.

6. The capacitive micro-displacement sensing robot foot device according to claim 1, characterized in that, The lower electrode plate is at least partially embedded in the rubber foot pad, or connected to the rubber foot pad by at least one of the following methods: gluing, injection coating, inverted fitting, through-hole gluing, and surface roughening bonding.

7. The capacitive micro-displacement sensing robot foot device according to claim 1, characterized in that, The rubber footpad is made of one of the following materials: polyurethane rubber, silicone rubber, nitrile rubber, natural rubber, or composite elastomer, and is formed by pouring and curing into a footpad mold.

8. The capacitive micro-displacement sensing robot foot device according to claim 1, characterized in that, The rubber footpad has a ground contact surface and an outer circumferential rounded transition surface; the ground contact surface is a composite contact surface composed of one or more of the following: a plane, a spherical crown surface, a micro-arc surface, and a textured plane; the outer circumferential rounded transition surface is used to reduce the concentration of edge stress of the rubber footpad and improve the smoothness of transition during rolling contact.

9. The capacitive micro-displacement sensing robot foot device according to claim 1, characterized in that, The capacitive micro-displacement sensor is a four-quadrant differential capacitive micro-displacement sensor. Multiple partition electrodes are provided on the upper and / or lower electrode plates to form multiple capacitance detection partitions between the upper and lower electrode plates. The tangential displacement of the robot foot causes differential changes in capacitance in different capacitance detection partitions, and the normal displacement of the robot foot causes common-mode changes in capacitance in multiple capacitance detection partitions.

10. The capacitive micro-displacement sensing robot foot device according to claim 9, characterized in that, The capacitive micro-displacement sensor is used to detect X-axis differential capacitance, Y-axis differential capacitance, and Z-axis common-mode capacitance; wherein, the X-axis differential capacitance and the Y-axis differential capacitance are obtained based on the differential changes in capacitance in different capacitance detection zones caused by the tangential displacement of the robot's foot; the Z-axis common-mode capacitance is obtained based on the common-mode changes in capacitance in multiple capacitance detection zones caused by the normal displacement of the robot's foot.

11. The capacitive micro-displacement sensing robot foot device according to claim 10, characterized in that, The capacitive micro-displacement sensing robot foot device also includes a signal processing and control unit, which is electrically connected to the capacitive micro-displacement sensor. The signal processing and control unit is used to calculate the relative micro-displacements in the X, Y, and Z directions based on the X-direction differential capacitance, the Y-direction differential capacitance, and the Z-direction common-mode capacitance, combined with a pre-calibrated relationship, and output the calculation results to the robot controller. The pre-calibrated relationship is the pre-calibrated relationship between the capacitance signal output by the capacitive micro-displacement sensor and the relative micro-displacements in the X, Y, and Z directions.

12. The capacitive micro-displacement sensing robot foot device according to claim 11, characterized in that, The connection component is provided with a lead wire channel, through which the lead wire or flexible circuit of the capacitive micro-displacement sensor is connected to the signal processing and control unit.

13. The capacitive micro-displacement sensing robot foot device according to claim 1, characterized in that, At least one of the connecting component, the upper electrode plate, the lower electrode plate, or the rubber foot pad is provided with a limiting structure. The limiting structure is used to limit the maximum relative displacement between the upper electrode plate and the lower electrode plate to prevent the capacitive micro-displacement sensor from being overloaded, collided with, or sheared.

14. A robot, characterized in that, It includes a body, multiple robot legs, and multiple capacitive micro-displacement sensing robot foot devices as described in any one of claims 1-13, each of the capacitive micro-displacement sensing robot foot devices being disposed at the lower leg end of the corresponding robot leg.

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