foot pressure sensor

Abstract

A kind of foot pressure sensor, including the sole plate for being connected with the robot sole, the sensing mechanism for sensing pressure change is arranged on the sole plate, further including connecting plate, the connecting plate is vertically fixed on sole plate, the sensing mechanism is fixed on connecting plate and the sensing mechanism is perpendicular to connecting plate.The beneficial effects of the utility model are: by setting connecting plate vertically fixed on sole plate and installing sensing mechanism thereon, avoid the zero drift problem caused by the deformation or vibration of sole plate when sensing mechanism directly contacts sole plate, to significantly improve the accuracy and stability of pressure detection.

Description

Technical Field

[0001] This utility model relates to a pressure sensor, and more particularly to a foot pressure sensor. Background Technology

[0002] In the field of robotics, foot pressure sensors are widely used to achieve intelligent walking, balance control, and terrain adaptation. Specific applications include industrial automation robots (such as warehouse handling robots) adjusting their gait by sensing real-time foot pressure distribution when performing tasks on complex terrain; service robots (such as robots assisting the elderly and disabled) ensuring smooth movement and avoiding slips in indoor environments; and rescue robots (such as earthquake detection robots) optimizing their footprints and improving stability in rugged terrain. During use, the sensor is typically integrated into the robot's footplate. When the foot contacts the ground, mechanical pressure acts on the sensor element (such as a piezoelectric material or transformer), converting it into an electrical signal (such as a voltage change). This signal is amplified and transmitted to the control system. The processor analyzes the pressure data to dynamically adjust joint movement, center of gravity distribution, and obstacle avoidance strategies, thereby achieving efficient and safe autonomous navigation. The entire process emphasizes real-time performance and accuracy to ensure reliable robot operation in changing environments.

[0003] However, existing technologies have significant drawbacks, particularly when the transformer used to sense pressure changes is directly fixed to the footplate. The fixing structure is prone to loosening due to long-term vibration or impact. This leads to unstable connections between the sensor and the footplate, causing deviations in the transmitted voltage signal (such as attenuation or noise interference), thus affecting the accuracy of pressure measurements. For example, after the robot has walked continuously for several hours, loosening may cause readings to shift, misleading the control system to make incorrect adjustments and potentially causing imbalance or falls. Furthermore, this fixing method lacks redundancy, resulting in high maintenance costs and difficulty adapting to high-frequency usage scenarios, ultimately reducing the robot's overall reliability and safety. Utility Model Content

[0004] In view of the shortcomings of the prior art, this utility model provides a foot pressure sensor that makes the zero point of the transformer less prone to change during use.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a foot pressure sensor, comprising a foot plate for connecting to the sole of a robot's foot, wherein a sensing mechanism for sensing pressure changes is provided on the foot plate, and a connecting plate is also provided, wherein the connecting plate is vertically fixed to the foot plate, and the sensing mechanism is fixed to the connecting plate and is perpendicular to the connecting plate.

[0006] The beneficial effects of this invention are as follows: By setting a connecting plate vertically fixed to the foot plate and mounting the sensing mechanism on it, the zero-point drift problem caused by foot plate deformation or vibration when the sensing mechanism directly contacts the foot plate is avoided, thus significantly improving the accuracy and stability of pressure detection. The vertical mounting of the sensing mechanism to the connecting plate ensures that its detection surface is parallel to the foot plate, further reducing measurement errors and enabling the sensor to be applied more reliably in the robot's dynamic walking environment. Extended beneficial effects include: this structure simplifies the installation process, reduces mechanical stress interference to the sensing element, and extends the sensor's lifespan; simultaneously, the vertical layout optimizes space utilization and facilitates integration into compact robot foot designs. As a preferred embodiment, the connecting plate can be made of rigid material (such as aluminum alloy) and fixed to the edge of the foot plate by welding or bolting. The sensing mechanism is then mounted on the vertical surface of the connecting plate by snap-fit ​​or adhesive. Its working principle is as follows: when the foot plate is subjected to pressure, the pressure is transmitted to the connecting plate through the foot plate. However, since the sensing mechanism is independent of the foot plate deformation zone, its internal components (such as strain gauges) only respond to vertical displacement, avoiding lateral interference and thus stabilizing the zero point. As another preferred approach, the sensing mechanism can be designed as a modular unit (e.g., an embedded sensor module) fixed in the guide groove of the connecting plate, and its detection surface is ensured to be parallel to the foot plate by an angle calibration tool; under pressure, the connecting plate acts as a rigid support to absorb vibration, and the sensing mechanism directly measures vertical deformation, reducing noise signals and improving the signal-to-noise ratio.

[0007] Furthermore, it also includes a positioning plate parallel to the connecting plate. The sensing mechanism includes two symmetrically arranged deformation plates with their ends fixed to the positioning plate and the connecting plate, respectively. A differential transformer is provided between the two deformation plates in the sensing mechanism. When the foot plate is pressed, the deformation plate deforms with the connection between it and the positioning plate as the axis, causing the differential transformer to generate a voltage change.

[0008] By adding a positioning plate and using a combination of symmetrical deformation plates and a differential transformer, this scheme effectively amplifies the slight deformation signal, improving the sensor's sensitivity and anti-interference capability. The deformation plate bends around the connection point of the positioning plate, ensuring linear and controllable deformation, while the differential transformer detects voltage changes caused by minute displacements. Combined with signal processing, the pressure value can be accurately quantified. Beneficial effects include: the symmetrical design compensates for temperature drift and external vibration effects, improving measurement consistency; the high-resolution characteristics of the differential transformer are suitable for dynamic load monitoring of the robot's feet, extending to complex terrain adaptation scenarios. As a preferred approach, the deformation plate can be made of an elastic alloy sheet (such as beryllium copper alloy) fixed at both ends to the hinge point of the positioning plate and the connecting plate, with the differential transformer integrated between the deformation plates. The working principle is as follows: when under pressure, the deformation plate bends, causing the movable part of the differential transformer to displace, changing the magnetic circuit coupling and generating a differential voltage signal, which is then amplified and output by subsequent circuitry. As another preferred approach, the output of the differential transformer is connected to a multi-stage operational amplifier circuit. The amplifier uses a differential input configuration to suppress common-mode noise. The working principle involves the transformation of the slight bending of the deformation sheet into the displacement of the iron core. The differential transformer induces a voltage difference, and the amplifier amplifies the microvolt-level signal to a processable range, making it easy for the microcontroller to acquire.

[0009] Furthermore, the differential transformer includes a coil, a movable iron core, and induction plates symmetrically arranged at both ends of the coil. The movable iron core is fixed on a connecting plate and used to connect with the deformation plates.

[0010] This structure achieves an optimized configuration of the differential transformer, with the movable iron core directly connected to the deformation plate, ensuring efficient and linear displacement transmission and improving the sensor's response speed and accuracy. The symmetrical layout of the coil and induction plate enhances signal balance, reduces external electromagnetic interference, and makes voltage changes more reliably reflect pressure values. Beneficial effects include: the rigid connection of the movable iron core reduces mechanical hysteresis, making it suitable for high-frequency dynamic measurements; the design of the induction plate simplifies the manufacturing process, reduces costs, and extends its application to harsh environments such as industrial robots. As a preferred approach, the movable iron core is designed as a columnar ferrite core, rigidly coupled to the end of the deformation plate via a linkage mechanism; its working principle is that when the deformation plate bends, it drives the iron core to move axially within the coil, changing the magnetic flux distribution. Eddy currents on the induction plate generate a voltage difference, which is proportional to the displacement. As another preferred approach, the coil is wound on a non-magnetic frame, and the induction plate is a copper foil patch fixed to the end of the coil; its working principle involves the iron core displacement modulating the magnetic field strength, the induction plate receiving the changing magnetic flux, and outputting a differential voltage, requiring no additional power supply for low-power detection.

[0011] Furthermore, the sensing element is fixed to the positioning plate and the distance between each sensing element and the coil is adjustable.

[0012] By allowing adjustable distance between the sensor and the coil, this approach expands the sensor's sensing range and sensitivity adaptability, enabling calibration based on different pressure amplitudes and improving versatility. The distance adjustment mechanism ensures the sensor maintains a linear response over a wide dynamic range, avoiding saturation or insufficient sensitivity issues. Beneficial effects include: enhanced sensor compatibility with different robot loads, reducing customization requirements; adjustable design facilitates on-site maintenance and calibration, extending to multiple application scenarios such as medical rehabilitation robots. As a preferred approach, the positioning plate features a guide rail system, with the sensor mounted via a slider assembly with locking screws. The working principle is as follows: loosening the screws moves the slider, changing the sensor's position; increasing the distance decreases sensitivity but expands the range, while decreasing the distance increases sensitivity. Adjustment and locking ensure stable measurement. As another preferred approach, the sensor is fixed to the positioning plate using a flexible bracket with a built-in fine-tuning knob. The working principle involves the knob driving a gear mechanism to translate the sensor, changing its gap with the coil, affecting magnetic coupling efficiency, and thus optimizing signal output strength.

[0013] Furthermore, the positioning plate is provided with an adjustment groove, and the sensing sheet is provided with a fixing bolt corresponding to the adjustment groove. The moving direction of the fixing bolt in the adjustment groove ensures that the end faces of the sensing sheet and the coil are always in a parallel state.

[0014] The design of the adjustment slot and fixing bolts ensures that the end face of the inductor remains parallel to the coil when it moves, eliminating measurement errors caused by angular deviations and significantly improving calibration accuracy and repeatability. The movement direction constraint mechanism simplifies the adjustment process, making operation more intuitive and reliable. Beneficial effects include: the parallel state maintains the uniformity of the magnetic field, improving signal consistency; the structure is durable and easy to operate, extending to long-term stable use in vibrating environments such as outdoor robots. As a preferred method, the adjustment slot is a straight guide slot, and the fixing bolt is mounted on the back of the inductor with a flat washer at the bolt head. The working principle is that when the bolt slides along the slot, the washer contacts the slot wall to restrict rotation, and the inductor only performs translational movement, ensuring that the end face is parallel to the coil. As another preferred method, the inductor is connected to the fixing bolt via a universal joint mechanism with a built-in self-balancing spring. The working principle involves the spring automatically compensating for tilting forces when the bolt moves, keeping the end face of the inductor horizontal without manual alignment. Attached Figure Description

[0015] Figure 1 This is an isometric view of an embodiment of the present utility model;

[0016] Figure 2 This is a front view of an embodiment of the present utility model;

[0017] Figure 3 This is a partial enlarged view of the sensing mechanism in an embodiment of the present invention. Detailed Implementation

[0018] This utility model embodiment provides a foot pressure sensor, such as... Figure 1-3 As shown: A foot plate 1 is included for connection to the robot's foot. A sensing mechanism 3 is mounted on the foot plate 1 to sense pressure changes. The foot plate 1 is made of metal or high-strength plastic to withstand the load during robot walking; those skilled in the art can use conventional materials such as aluminum alloy. A connecting plate 2 is vertically fixed to the foot plate 1 and rigidly connected to it by welding or bolts. The sensing mechanism 3 is fixed to the connecting plate 2 and is perpendicular to it. This arrangement avoids the zero-point shift caused by deformation of the foot plate 1 when the sensing mechanism 3 is directly mounted on it, thus improving detection accuracy. The perpendicularity of the sensing mechanism 3 to the connecting plate 2 ensures that the sensing mechanism 3 is parallel to the foot plate 1. The positioning plate 4 is parallel to the connecting plate 2. The positioning plate 4 is fixed to the foot plate 1 by a bracket. The sensing mechanism 3 includes two symmetrically arranged deformation plates 31. The deformation plates 31 are made of elastic metal sheets such as stainless steel. Their two ends are fixed to the positioning plate 4 and the connecting plate 2 respectively. The differential transformer 32 is arranged between the two deformation plates 31. When the foot plate 1 is pressed, the deformation plates 31 undergo slight deformation with the connection between them and the positioning plate 4 as the axis. This deformation is converted into voltage change by the differential transformer 32.

[0019] The differential transformer 32 includes a coil 321, a movable iron core 322, and induction plates 323 symmetrically arranged at both ends of the coil 321. The coil 321 is wound around an insulating frame and connected to an external power supply. The movable iron core 322 is fixed on the connecting plate 2 and connected to the deformation plates 31, i.e., the deformation plates 31 are fixed at both ends of the movable iron core 322. The induction plates 323 are fixed on the positioning plate 4. The distance between each induction plate 323 and the coil 321 is adjustable. By adjusting the distance, the sensing range can be increased to meet different pressure detection requirements. The positioning plate 4 is provided with an adjustment groove 41. A fixing bolt 3231 is provided on the induction plate 323 corresponding to the adjustment groove 41. When the fixing bolt 3231 moves in the adjustment groove 41, the end faces of the induction plate 323 and the coil 321 are always parallel to each other to ensure measurement accuracy. The fixing bolt 3231 is made of standard threaded parts, which can be easily implemented by those skilled in the art.

[0020] When pressure is applied to the robot's foot, the foot plate 1 is compressed, causing the connecting plate 2 and the deformation plate 31 fixed thereon to move. The deformation plate 31 undergoes slight elastic deformation with its connection point with the positioning plate 4 as the axis. The deformation of the deformation plate 31 drives the movable iron core 322 to move within the coil 321, changing the magnetic coupling relationship between the movable iron core 322 and the sensing plate 323. The differential transformer 32 then generates a voltage change signal. This voltage change signal is amplified by an external circuit such as a signal amplifier (existing technology). The amplified signal is used to accurately measure the pressure change value, realizing real-time monitoring of the robot's foot pressure.

[0021] The above embodiments are merely one preferred embodiment of the present utility model. Ordinary changes and substitutions made by those skilled in the art within the scope of the present utility model's technical solution are all included within the protection scope of the present utility model.

Claims

1. A foot pressure sensor, comprising a foot plate for connection to the sole of a robot's foot, wherein the foot plate is provided with a sensing mechanism for sensing pressure changes, characterized in that: It also includes a connecting plate, which is vertically fixed to the foot plate, and the sensing mechanism is fixed to the connecting plate and perpendicular to the connecting plate.

2. The foot pressure sensor according to claim 1, characterized in that: It also includes a positioning plate parallel to the connecting plate. The sensing mechanism includes two symmetrically arranged deformation plates with their ends fixed to the positioning plate and the connecting plate, respectively. A differential transformer is provided between the two deformation plates in the sensing mechanism. When the foot plate is pressed, the deformation plate deforms with the connection between it and the positioning plate as the axis, causing the differential transformer to generate a voltage change.

3. The foot pressure sensor according to claim 2, characterized in that: The differential transformer includes a coil, a movable iron core, and induction plates symmetrically arranged at both ends of the coil. The movable iron core is fixed on a connecting plate and is used to connect with the deformation plates.

4. The foot pressure sensor according to claim 3, characterized in that: The induction plates are fixed to the positioning plate and the distance between each induction plate and the coil is adjustable.

5. The foot pressure sensor according to claim 4, characterized in that: The positioning plate is provided with an adjustment groove, and the induction plate is provided with a fixing bolt corresponding to the adjustment groove. The moving direction of the fixing bolt in the adjustment groove ensures that the end faces of the induction plate and the coil are always parallel.

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