A compliant control method and implementation device for a lower limb rehabilitation robot

Abstract

This invention relates to a compliant control method and implementation device for a lower limb rehabilitation robot. The implementation device includes an upper pedal, a base plate, and an elastic beam disposed between the pedal and the base plate. The elastic beam passes through a connecting part at the bottom of the pedal and a connecting piece in the middle of the base plate, connecting the pedal and the base plate together. Strain gauges are disposed on the elastic beam to convert the deformation of the elastic beam into an electrical signal. When the plantar force applied to the pedal changes abruptly, the electrical signal will change abnormally accordingly. The control system detects and judges in real time whether the fluctuation of the current signal is within the normal range, thereby issuing a stop signal to the rehabilitation robot when the plantar force changes abruptly or falls below the normal range, thus achieving compliant control. The structure is simple and easy to promote.

Description

Technical Field

[0001] This invention relates to the field of rehabilitation equipment, specifically to a compliant control method and implementation device for a lower limb rehabilitation robot. Background Technology

[0002] Currently, China has a large demand for rehabilitation services globally, with a significant number of patients suffering from musculoskeletal disorders. Therefore, the domestic market for medical rehabilitation robots is enormous.

[0003] Currently used rehabilitation robots typically consist of several rigid links connected by joint drive modules. Actuators drive these links to move according to an algorithm set by the controller. The rigid link structure facilitates precise positioning by controlling joint angles. However, when users train with rehabilitation robots, muscle spasms frequently occur and are difficult to avoid due to factors such as muscle degeneration. If these spasms are not detected and communicated to the therapist in a timely manner, they can lead to muscle strain from the robot's rigid joints, or even serious medical accidents such as fractures.

[0004] Therefore, it is essential to add compliant control to rehabilitation robots. Currently, the most common way to achieve compliant control is to use force sensors to detect motion trajectories and feed them back to a computer, which then controls the rehabilitation robot to adjust in a timely manner to better fit the patient's motion trajectory. This method has relatively high technical requirements and is also more expensive. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a compliant control method and device for a lower limb rehabilitation robot. The method is simple in structure, easy to use, and can achieve compliant control, thus avoiding secondary injury to the patient.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A device for implementing compliant control of a lower limb rehabilitation robot includes an upper pedal, a base plate, and an elastic beam disposed between the pedal and the base plate. The upper pedal has two connecting parts at its bottom, and the base plate has a protruding connecting piece in the middle. The elastic beam passes through the connecting parts at the bottom of the pedal and the connecting piece in the middle of the base plate, connecting the pedal and the base plate together. Strain gauges are disposed on the elastic beam to convert the deformation of the elastic beam into electrical signals, which are then used by the control system to determine whether the change in plantar force is within the normal range.

[0008] Furthermore, the elastic beam has a square cross-section and two sets of strain gauges are provided along the length of the elastic beam, located on both sides of the bottom plate connector. Each set of strain gauges has four strain gauges, which are symmetrically attached to the four sides of the elastic deformation beam.

[0009] Furthermore, both the upper pedal and the base plate are made of aluminum alloy.

[0010] A compliant control method for a lower limb rehabilitation robot is disclosed. This method uses an implementation device to achieve compliant control of the lower limb rehabilitation robot. The implementation device is installed on the lower limb rehabilitation robot as a double foot pedal. The patient stands on the double foot pedal to perform rehabilitation exercises. When the upper pedal in the implementation device is subjected to pressure, the elastic beam deforms accordingly. The strain gauge group attached to the elastic beam converts the deformation of the elastic beam into an electrical signal. When the foot force applied to the pedal changes abruptly, the electrical signal will change abnormally. The control system detects and judges in real time whether the fluctuation of the current signal is within the normal range. Therefore, when the foot force changes abruptly or falls below the normal range, a stop signal is sent to the rehabilitation robot to achieve compliant control.

[0011] Specifically, the strain gauge is connected to a variable resistor. The deformation of the elastic beam is converted into a change in the resistance of the variable resistor, which in turn is converted into a change in current. The variable resistor is connected to the input of a trigger, and the output of the trigger is connected to the motor switch of the lower limb rehabilitation robot. During normal operation, the output of the trigger is at a high level. When the foot force on the pedal suddenly decreases or falls below the set value, the variable resistor R will suddenly decrease, the input of the trigger will change from a high level to a low level, and the output will output a low level, causing the motor to stop working. Otherwise, when the resistance value is within the normal range, the input is at a high level, the output level remains unchanged, and the motor works normally.

[0012] Beneficial effects:

[0013] 1. The present invention has a simple structure. It obtains the magnitude of the human-machine interaction force by deforming only an elastic deformation beam and using a strain gauge group. By converting the deformation of the deformation beam into an electrical signal, the magnitude of the human-machine interaction force is monitored in real time, achieving compliant control and avoiding secondary injury to the patient during rehabilitation. It has low cost, is easy to promote, and has low maintenance costs.

[0014] 2. The present invention has high portability. The structure itself is a pedal used in lower limb rehabilitation robots. It can be directly installed on existing lower limb rehabilitation medical devices, enabling widespread adoption of compliant control, improving the safety of existing rehabilitation devices, and greatly reducing the cost of upgrading and replacing rehabilitation devices. Attached Figure Description

[0015] Figure 1 A schematic diagram of the overall structure of the present invention;

[0016] Figure 2 Schematic diagram of the upper pedal structure of this invention;

[0017] Figure 3 Schematic diagram of the elastic beam structure of this invention;

[0018] Figure 4 Schematic diagram of the base plate structure of this invention;

[0019] Figure 5 A simplified control flow diagram of the present invention.

[0020] Reference numerals: 1 Upper pedal, 2 Elastic beam, 3 Connecting part, 4 Base plate, 5 Connecting piece, 6 Strain gauge, 7 Front baffle, 8 Through hole. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1-4 As shown, a device for implementing compliant control of a lower limb rehabilitation robot includes an upper pedal 1, a base plate 4, and an elastic beam 2 disposed between the upper pedal 1 and the base plate 4. The upper pedal 1 has two connecting parts 3 at its bottom, and the base plate 4 has a protruding connecting piece 5 in the middle. The elastic beam 2 passes through the connecting piece 5 in the middle of the base plate 4 and is connected at both ends to the connecting parts 3 of the upper pedal 1, thereby connecting the upper pedal 1 and the base plate 4 together. The elastic beam 2 is provided with strain gauges 6, which are used to convert the deformation of the elastic beam 2 into electrical signals, which are then used by the control system to determine whether the change in foot force is within the normal range.

[0023] like Figure 2 As shown, the upper pedal 1 has a front baffle 7 at its front end, which is used to limit the user's foot and prevent it from slipping off the pedal. The connecting part 3 at the bottom of the upper pedal 1 is designed with a cavity structure that matches the elastic beam 2. During installation, both ends of the elastic beam 2 are inserted into the cavity and fixed by installing nuts and bolts.

[0024] like Figure 3 As shown, the elastic beam 2 has a square cross-section. Along the length of the elastic beam 2, there are two sets of strain gauges 6, located on both sides of the bottom plate 4 connector 5. Each set of strain gauges 6 has 4 gauges, which are symmetrically attached to the four sides of the elastic deformation beam.

[0025] like Figure 4 As shown, a connector 5 is provided in the middle of the base plate 4. The connector 5 is integrally formed with the base plate 4. A through hole 8 for supporting the elastic beam 2 is provided in the middle. The shape and size of the through hole 8 are matched with the elastic beam 2.

[0026] Preferably, both the upper pedal 1 and the base plate 4 are made of aluminum alloy.

[0027] The implementation device described in this invention is used as a double foot pedal mounted on a lower limb rehabilitation robot. The patient stands on the foot pedal to perform rehabilitation exercises. With the help of this device, compliant control of the rehabilitation robot can be achieved. When the patient stands on the foot pedal to perform rehabilitation exercises, when the upper pedal 1 in the device is subjected to pressure, the elastic beam 2 deforms accordingly. The six sets of strain gauges attached to the elastic beam 2 convert the deformation of the elastic beam 2 into an electrical signal. When the foot force applied to the pedal changes abruptly, the electrical signal will change abnormally. The control system detects and judges in real time whether the fluctuation of the current signal is within the normal range, so that when the foot force changes abruptly or falls below the normal range, a stop signal can be sent to the rehabilitation robot to achieve compliant control.

[0028] Specifically, the control system detects current changes through a range circuit. The strain gauge 6 is connected to a variable resistor R. The elastic beam 2 deforms under pressure, and this deformation is converted into a change in the resistance of the variable resistor, which in turn is converted into a change in current. The variable resistor is connected to the input of a trigger, and the output of the trigger is connected to the motor switch of the lower limb rehabilitation robot. During normal operation, the trigger output is at a high level. When the foot pressure on the pedal suddenly decreases or falls below a set value, the variable resistor R suddenly decreases, the trigger input changes from high to low, and the output outputs a low level, causing the motor to stop working. Otherwise, when the resistance value is within the normal range, the input is at a high level, and the output level remains unchanged, allowing the motor to work normally. See Appendix for the control flow. Figure 5 .

[0029] The invention also includes pedals of different sizes, suitable for both men and women.

[0030] In one specific embodiment, the maximum length of the upper pedal designed in this invention is 331.00 mm, the height of the front baffle on the pedal is 30.00 mm, the thickness of the pedal body is 10.00 mm, and the height of the front and rear connecting parts under the pedal is 60.00 mm; the elastic beam is 260.00 mm long and has a 30*30 mm square cross-section; the strain gauge group consists of eight strain gauges, with four in each group arranged symmetrically around the deformation beam in two groups; the base plate is 300.00 mm long and 150.00 mm wide, and the height of the intermediate connecting piece is 50.00 mm.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A device for implementing compliant control of a lower limb rehabilitation robot, characterized in that, The device includes an upper pedal, a base plate, and an elastic beam positioned between the pedal and the base plate. The upper pedal is located above the base plate and has two connecting parts at its bottom. The base plate has a protruding connecting piece in the middle. The elastic beam passes through the connecting piece in the middle of the base plate and connects to the connecting parts at the bottom of the upper pedal at both ends, thus connecting the pedal and the base plate together. Strain gauges are installed on the elastic beam to convert the deformation of the elastic beam into electrical signals, which are then used by the control system to determine whether the change in foot force is within the normal range. The device is installed on the lower limb rehabilitation robot as a double-foot pedal. The patient stands on the double-foot pedal to perform rehabilitation exercises. The control system detects current changes through a range circuit. The strain gauges are connected to a variable resistor, which is connected to the input of a trigger. The output of the trigger is connected to the motor switch of the lower limb rehabilitation robot. When the foot force on the pedal suddenly decreases or falls below a set value, the variable resistor R suddenly decreases, the input of the trigger changes from high level to low level, and the output outputs a low level, causing the motor to stop working.

2. The device for implementing compliant control of a lower limb rehabilitation robot according to claim 1, characterized in that, The elastic beam has a square cross-section. Along the length of the elastic beam, there are two sets of strain gauges located on both sides of the bottom plate connector. Each set of strain gauges has four gauges, which are symmetrically attached to the four sides of the elastic deformation beam.

3. The device for implementing compliant control of a lower limb rehabilitation robot according to claim 1, characterized in that, Both the upper pedal and the base plate are made of aluminum alloy.

4. A compliant control method for a lower limb rehabilitation robot, characterized in that, This compliant control method uses the implementation device described in claim 1 to achieve compliant control of a lower limb rehabilitation robot. The implementation device is installed on the lower limb rehabilitation robot as a double foot pedal. The patient stands on the double foot pedal to perform rehabilitation exercises. When the upper pedal in the implementation device is subjected to pressure, the elastic beam deforms accordingly. The strain gauge group attached to the elastic beam converts the deformation of the elastic beam into an electrical signal. When the foot force applied to the pedal changes abruptly, the electrical signal will change abnormally. The control system detects and judges in real time whether the fluctuation of the current signal is within the normal range. Therefore, when the foot force changes abruptly or falls below the normal range, it can send a stop signal to the rehabilitation robot to achieve compliant control.

5. The compliant control method for a lower limb rehabilitation robot according to claim 4, characterized in that, The strain gauge is connected to a variable resistor. The deformation of the elastic beam is converted into a change in the resistance of the variable resistor, which in turn is converted into a change in current. The variable resistor is connected to the input of a trigger, and the output of the trigger is connected to the motor switch of the lower limb rehabilitation robot. During normal operation, the output of the trigger is at a high level. When the foot force on the pedal suddenly decreases or falls below the set value, the variable resistor R will suddenly decrease, the input of the trigger will change from a high level to a low level, and the output will output a low level, causing the motor to stop working. Otherwise, when the resistance value is within the normal range, the input is at a high level, the output level remains unchanged, and the motor works normally.

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