Powered exoskeleton device with force feedback detection

Abstract

The present application relates to the field of intelligent wearing equipment, in particular to torque calculation technology of exoskeleton equipment, which is achieved by the following scheme: the power-assisted exoskeleton equipment with force feedback detection comprises an outer connecting rod and a driving device, a force sensor for detecting the torque received in the deformation process of the outer connecting rod is installed on the outer connecting rod; a PCB board is further included, a control module is installed on the PCB board, the control module is used to collect torque data of the force sensor, and the running state of the driving device is controlled based on the torque data. The purpose of the present application is to provide the power-assisted exoskeleton equipment with force feedback detection. The present application avoids using the intermediate quantity of current value to calculate the torque, but directly measures and analyzes the stress condition, improves the measurement accuracy, and also improves the dynamic response speed.

Description

Technical Field

[0001] This invention relates to the field of smart wearable devices, and more specifically to torque calculation technology for exoskeleton devices. Background Technology

[0002] An exoskeleton is a wearable mechatronic device that enhances human mobility through mechanical structures. Its core function is to assist the human body in bearing weight or enhancing motor function. The device uses drive mechanisms at the joints, typically motors, to output assist torque and move synchronously with the body's limbs. Exoskeletons are used in various technical fields. In industry, they can reduce the load on the lower back and legs when lifting heavy objects; in medical rehabilitation, they can be used to rebuild walking function and provide standing / movement assistance for injured patients; and in the military, they can be used for individual soldiers carrying heavy loads during marches.

[0003] Structurally, exoskeletons typically consist of a drive unit and a connection unit. The connection unit is used to connect to the human body, while the drive unit provides power to move the connection unit, thereby moving the human body. For example, the connection unit connects to the user's legs, and the drive unit is a motor. Driven by the motor, the connection unit rises, thereby raising the human leg.

[0004] This process requires torque acquisition and drive device control. Torque acquisition involves predicting the required human movement and matching the required torque, while drive device control involves controlling the output power or starting / stopping the drive device. If errors occur in torque acquisition, output, or matching during drive device control, it can lead to joint damage due to over-assistance, or insufficient assistance, failing to achieve the decompression effect. In existing technologies, torque acquisition often employs current calculation methods. For example, Chinese patent document CN116636965A discloses a human exoskeleton device, whose drive device is also a motor. It uses a motor current loop servo control algorithm to calculate the required output torque based on the motor's current value, further generating a control strategy. The reason why existing technologies mostly use current calculation methods is that, firstly, the hardware cost is low, directly utilizing the motor's built-in Hall sensor / sampling resistor, eliminating the need for an additional force sensor. Secondly, system integration is simple; the current signal can be directly obtained through the motor driver, avoiding mechanical structure modifications.

[0005] However, this technical solution is an indirect force detection technology, which inevitably has the following technical defects: First, it suffers from dynamic response lag. This technology is poorly adaptable in dynamic scenarios. For example, in scenarios with sudden load changes, a sudden external force causes back EMF disturbances in the motor, and the current signal cannot reflect the true torque. That is, when the user suddenly releases the load, causing it to fall, the back EMF of the motor interferes with the current signal, and the system mistakenly interprets it as still requiring assistance, when in fact it should be braking. Second, it has weak anti-interference capabilities. Because torque detection relies on the indirect quantity of current, the current value can be erroneous due to motor temperature drift, gearbox friction jerking nonlinearity, electromagnetic compatibility interference, and other factors. Summary of the Invention

[0006] The purpose of this invention is to provide a assisted exoskeleton device with force feedback detection. This invention avoids using current as an intermediate quantity to calculate torque, instead directly measuring and analyzing the force applied, thus improving measurement accuracy and dynamic response speed.

[0007] This invention is achieved through the following technical solution: a force-feedback detection assisted exoskeleton device, comprising an external connecting rod and a drive device. A force sensor is installed on the outer connecting rod to detect the torque received during the deformation process of the outer connecting rod; It also includes a PCB board on which a control module is mounted. The control module is used to receive torque data from the force sensor and control the operating state of the drive device based on the torque data.

[0008] As a preferred embodiment of the present invention, when the control module receives the torque data as a torque in the first direction, it controls the drive device to start operation. When the torque data is transformed into a torque in the second direction, the drive device is controlled to continue operating; If the torque data is not only a torque in the second direction, but the torque value is also greater than the preset stopping torque threshold, then the drive device is controlled to stop.

[0009] As a preferred embodiment of the present invention, when the control module receives the torque data as a torque in the first direction and the torque data is greater than the preset start-up torque threshold, it controls the drive device to start operation.

[0010] As a preferred embodiment of the present invention, the force sensor is a tension sensor, a pressure sensor, or a bending moment sensor.

[0011] As a preferred embodiment of the present invention, the force sensor is a resistive strain gauge.

[0012] As a preferred embodiment of the present invention, the PCB board is installed inside the driving device.

[0013] As a preferred embodiment of the present invention, the external connecting rod includes an output rod and a connecting plate, the connecting plate is connected to the driving device, and the output rod has a container slot for placing the force sensor, and the container slot is covered with a cover plate.

[0014] As a preferred embodiment of the present invention, the driving device includes a housing and a motor body installed within the housing. The motor body includes an output shaft, and a coupling port is connected to the output shaft and connected to the external connecting rod.

[0015] As a preferred embodiment of the present invention, the connecting plate has a central connecting area in the middle, and the central connecting area is connected to the connecting shaft port.

[0016] In summary, the present invention has the following beneficial effects: 1. The invention avoids using the intermediate value of current to calculate torque, and instead directly measures and analyzes the force through a force sensor, improving the accuracy of measurement and the speed of dynamic response.

[0017] 2. In this case, the force sensor uses a resistive strain gauge. It directly senses the minute deformation of the drive shaft caused by torque, minimizing the physical quantity conversion steps, resulting in high accuracy and good linearity.

[0018] 3. Resistance strain gauges have extremely small mass and almost no inertia, enabling them to track rapid changes in torque in real time, thus better meeting the low latency and high precision requirements of the entire solution. Their compact size allows for direct connection to the output rod, requiring almost no alteration to the original equipment structure.

[0019] 4. The PCB board is installed in the gap between the motor body and the coupling port, which makes the whole device more compact and improves space utilization.

[0020] 5. When starting the operation, not only the direction of the torque but also its magnitude is determined. This prevents the motor from malfunctioning due to slight leg movements by the user that are not actually intended to start the operation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of Example 1; Figure 2 This is a schematic diagram showing the connection between the drive unit and the external connecting rod; Figure 3 This is an exploded view of the components in the drive unit.

[0022] In the diagram: 1. External connecting rod, 11. Output rod, 12. Connecting plate, 13. Middle connecting area, 14. Container tank, 15. Cover plate, 2. Drive device, 21. Housing, 22. Motor body, 221. Output shaft, 23. Coupling port, 3. Power supply device, 4. Force sensor, 5. PCB board. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings.

[0024] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0025] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the described elements without departing from the scope of this specification. Various processes or components may be appropriately omitted, substituted, or added to the examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.

[0026] Example 1, as Figure 1 As shown, the force-feedback detection assisted exoskeleton device includes two drive units 2, which provide the driving force for the entire exoskeleton device. A power supply unit 3 is provided between the two drive units 2 to provide power to the two drive units 2.

[0027] like Figure 3 As shown, in this embodiment, the driving device 2 is a motor, which includes a housing 21 and a motor body 22 installed therein. The motor body 22 includes an output shaft 221, which is connected to a coupling port 23. When the motor body 22 is powered on, the coupling port 23 rotates accordingly. The PCB board 5 is mounted in the gap between the motor body 22 and the coupling port 23, which makes the entire device more compact and improves space utilization. The PCB board 5 is equipped with a control module, which is a microcontroller (MCU) or microprocessor (MPU) in hardware. It typically includes a power supply circuit, a clock circuit, a reset circuit, a debugging interface, and external memory such as DDR RAM. The control module implements various control functions through a preset software program. In this embodiment, the PCB board 5 is equipped with a cable connected to the force sensor 4, allowing the control module to obtain the torque data of the force sensor 4 through the cable.

[0028] like Figure 2As shown, the outer connecting rod 1 comprises two main parts: a connecting plate 12 and an output rod 11. The connecting plate 12 is generally disc-shaped, with a central connecting area 13 that connects to the coupling port 23. When the motor body 22 runs, the entire outer connecting rod 1 rotates relative to the outer casing 21. The output rod 11 has a container slot 14, in which the force sensor 4 is placed, and a cover plate 15 protects the force sensor 4. The output rod 11 is connected to the human body; for example, if used in a leg joint, the output rod 11 connects to the leg.

[0029] In this case, the control of the operating state of the motor body 22 comes from the control module on the PCB board 5, which generates a control strategy based on the torque data transmitted from the force sensor 4.

[0030] Force sensor 4 can be a mature device used in existing technologies for measuring torque, such as a tension sensor, pressure sensor, or bending moment sensor. In this example, a resistive strain gauge is used. Compared to other sensors, firstly, the resistive strain gauge directly senses the minute deformation of the drive shaft caused by torque, minimizing the physical quantity conversion steps, resulting in high accuracy and good linearity. Secondly, this application is suitable for exoskeletons, where torque is often dynamically changing. The strain gauge has extremely small mass and almost no inertia, enabling it to track rapid changes in torque in real time, better meeting the low latency and high accuracy requirements of the entire solution. Thirdly, as a device connected to the human body, the exoskeleton requires a lightweight design. A standard strain gauge torque sensor can be made very compact and directly connected to the output rod 11, with almost no change to the original device structure.

[0031] In this case, taking the connection between the output rod 11 and the human leg as an example, the control logic of the control module is as follows: When the user controls the leg to rise, the force sensor detects a torque in the first direction, which is upward. Upon receiving this data, the control module activates the drive unit 2, engaging the motor to provide an upward assist force to the user's leg.

[0032] After receiving assistance, the user's legs will naturally reduce their own movement force. As the user's movement force decreases, the direction of the torque received by the force sensor will change from upward to downward, i.e., it will become a second direction. At this time, the control module continues to allow the motor to provide upward power as normal.

[0033] When the user wants to stop the upward movement, they will completely stop exerting force. At this time, the torque received by the force sensor is still downward, but in terms of value, since the user is not exerting any force, the torque value will be very large, exceeding the stopping torque threshold initially set by the engineers. At this point, the control module will stop the motor and the external linkage 1 will stop moving.

[0034] When the user controls the legs to descend, the same logic applies, except that the first direction is downward and the second direction is upward.

[0035] Thus, the invention avoids using the intermediate value of current to calculate torque, and instead directly measures and analyzes the force through the force sensor 4, improving the accuracy of the measurement and the speed of dynamic response.

[0036] Example 2 differs from Example 1 in that the control logic of the control module is optimized.

[0037] In this embodiment, a threshold judgment of the torque magnitude upon activation is added. Taking the user's leg-raising action as an example, when the user controls the leg to rise, the force sensor senses a torque in the first direction, which is upward. After receiving this data, the control module does not immediately start the drive device 2; instead, it needs to judge the magnitude of the torque. It determines whether the torque exceeds a preset activation torque threshold. If it does, the motor intervenes to provide an upward assist force to the user's leg.

[0038] This design is intended to prevent the motor from malfunctioning due to slight leg movements that the user may not actually intend to lift their leg.

Claims

1. A force-feedback detection assisted exoskeleton device, comprising an external connecting rod (1) and a drive device (2), characterized in that: A force sensor (4) is installed on the outer connecting rod (1) to detect the torque received during the deformation process of the outer connecting rod (1). It also includes a PCB board (5) and a control module, the control module being used to receive torque data from the force sensor (4) and control the operating state of the drive device (2) based on the torque data. When the control module receives the torque data as a torque in the first direction, it controls the drive device (2) to start running; When the torque data is transformed into a torque in the second direction, the drive device (2) is controlled to continue operating; If the torque data is not only a torque in the second direction, but the torque value is greater than the preset stopping torque threshold, then the drive device (2) is controlled to stop. The second direction is opposite to the first direction. When the control module receives the torque data as a torque toward the first direction and the torque data is greater than the preset start-up torque threshold, it controls the drive device (2) to start running.

2. The assisted exoskeleton device with force feedback detection according to claim 1, characterized in that: The force sensor is a tension / compression sensor, a torque sensor, or a bending moment sensor.

3. The assisted exoskeleton device with force feedback detection according to claim 1, characterized in that: The force sensor includes a sensing element, which is a resistive strain gauge, a piezoelectric crystal, or a semiconductor strain gauge.

4. The assisted exoskeleton device with force feedback detection according to claim 1, characterized in that: The PCB board (5) is installed inside the drive device (2).

5. The assisted exoskeleton device with force feedback detection according to claim 1, characterized in that: The external connecting rod (1) includes an output rod (11) and a connecting plate (12). The connecting plate (12) is connected to the driving device (2). The output rod (11) has a container slot (14) for placing the force sensor (4). The container slot (14) is covered with a cover plate (15).

6. The assisted exoskeleton device with force feedback detection according to claim 5, characterized in that: The drive device (2) includes a housing (21) and a motor body (22) installed in the housing (21). The motor body (22) includes an output shaft (221) and a coupling port (23) is connected to the output shaft (221). The coupling port (23) is connected to the outer connecting rod (1).

7. The assisted exoskeleton device with force feedback detection according to claim 1, characterized in that: The driving device (2) and the external connecting rod (1) are both two sets, and a power supply device (3) is provided between the two driving devices (2).

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