Flexible continuum robot shape and environment perception control system based on distributed piezoelectric transducer array

Abstract

The invention provides a flexible continuum robot shape and environment perception control system based on a distributed piezoelectric transducer array. Comprising a flexible continuum robot structure, a flexible robot bending driver, a distributed piezoelectric transducer array, a main controller circuit, a microcontroller circuit, a multiplexer circuit, a power amplifier circuit and a signal measuring and amplifying circuit. The flexible continuum robot structure is connected to a flexible robot bending driver through a rope and a fluid channel; distributed piezoelectric transducer arrays are arranged on the surface of the flexible continuum robot structure and in the flexible continuum robot structure; based on the sensed feedback information such as the shape of the robot, the external environment and the contact state, a closed-loop control system is constructed, accurate control over the shape of the flexible robot and better environment obstacle avoidance and contact control are achieved, and the operation accuracy, adaptability and safety of the robot are greatly improved.

Description

Technical Field

[0001] The present invention belongs to the field of robot technology, and in particular relates to a flexible continuum robot shape and environment perception control system based on a distributed piezoelectric transducer array. Background Art

[0002] Flexible continuum robots have a wide range of applications in industries such as industry, agriculture, food, and medicine. For example, in industry, slender flexible robots are needed to pass through narrow cavities to enter the interior of equipment to perform non-destructive testing and in-situ repair operations. In agriculture, flexible robots are needed as robotic arms to pick, prune, and apply pesticides to agricultural products. In the food industry, flexible robots are needed as robotic arms to grab food. However, existing flexible continuum robots generally lack the ability to perceive their own shape, their surroundings, and their contact status with the environment. The lack of perceptual feedback makes it difficult to accurately control the shape of flexible robots, and it is difficult to control flexible robots to avoid obstacles, navigate, and safely contact the environment in complex and narrow environments.

[0003] At present, most flexible continuum robots lack shape and environmental perception and cannot adopt closed-loop feedback control. They can only adopt open-loop control based on kinematics, mechanics and other models, which greatly limits the accuracy and safety of their operation control. There are methods in the literature that use external camera vision to extract the shape of flexible robots, but this method is not suitable for narrow cavity environments, and the camera is easily blocked, illuminated, turbid liquids, dust and other interferences and fails. There are also methods in the literature that use electromagnetic trackers to sense the shape of flexible robots, but this method also requires the arrangement of large electromagnetic transmitting and receiving devices in the robot's external environment, so it is not suitable for narrow cavity environments and is very expensive. There are also methods in the literature that use fiber Bragg gratings embedded in flexible robots to achieve shape perception, but this method is very expensive and can only sense the shape of the flexible robot but not its surrounding environment. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a flexible continuum robot shape and environment perception control system based on a distributed piezoelectric transducer array in view of the deficiencies of the prior art, which has three modes: shape perception, environmental distance perception, and environmental contact perception, and realizes a closed-loop control system based on the perception feedback information, significantly improving the control accuracy and anti-interference ability of the flexible continuum robot's own shape, environmental obstacle avoidance, and environmental contact, and greatly improving its operational performance and safety. The system has the advantages of rich functions, compact structure, strong environmental applicability, strong scalability, and low implementation cost.

[0005] The system includes a flexible continuum robot structure, a flexible robot bending actuator, a distributed piezoelectric transducer array, a main controller circuit, a microcontroller circuit, a multiplexer circuit, a power amplifier circuit, and a signal measurement and amplification circuit;

[0006] The flexible continuum robot structure is connected to the flexible robot bending actuator via a rope and a fluid channel;

[0007] A distributed piezoelectric transducer array is arranged on the surface of the flexible continuum robot structure and inside the flexible continuum robot structure;

[0008] The main controller circuit is connected to the flexible robot bending driver and the microcontroller circuit via a cable;

[0009] The distributed piezoelectric transducer array is composed of more than two piezoelectric transducers, and each piezoelectric transducer serves as a unit node;

[0010] The multiplexer circuit is connected to the power amplifier circuit and the signal measurement and amplification circuit via a cable;

[0011] The microcontroller circuit is connected to the power amplifier circuit and the signal measurement and amplification circuit through a cable.

[0012] The microcontroller circuit, multiplexer circuit, power amplifier circuit, and signal measurement and amplification circuit can be integrated inside the flexible continuum robot structure, or be arranged on an external separate circuit board.

[0013] The flexible continuum robot structure is driven by rope, pneumatic or magnetic drive.

[0014] The main controller circuit parses the received operation commands into set values ​​of shape control, obstacle avoidance control, and contact control according to the task requirements, calculates and synthesizes the output commands through the control algorithm, obtains the driving commands of the flexible robot, and sends the driving commands to the flexible robot bending driver. The flexible robot bending driver generates driving force to drive the flexible continuum robot structure to bend and change its shape.

[0015] More than two piezoelectric transducers are respectively embedded on the surface and inside of the flexible continuum robot structure for generating and receiving ultrasonic waves; the more than two piezoelectric transducers form a distributed piezoelectric transducer array.

[0016] Each piezoelectric transducer is in a cubic shape, having 6 faces and 3 pairs of electrodes, wherein a pair of electrodes is provided on the faces opposite to each other of the piezoelectric transducers;

[0017] The electrodes of the piezoelectric transducer are connected to a multiplexer circuit via cables.

[0018] The microcontroller circuit is used to generate an AC high-frequency signal. After amplifying the voltage and current of the AC high-frequency signal through a power amplifier circuit, a unit node of the distributed piezoelectric transducer array is selected through a multiplexer circuit, and a pair of electrodes in the unit node 3 are selected to apply voltage and current to generate ultrasonic waves in the corresponding direction.

[0019] The flexible continuum robot structure has three working modes: shape perception, environmental distance perception and environmental contact perception.

[0020] When the flexible continuum robot structure is in the shape sensing mode, the microcontroller circuit selects to control a piezoelectric transducer to transmit ultrasonic waves along the surface of the flexible continuum robot structure or transmitted inside, and at the same time selects to control the remaining piezoelectric transducers to receive ultrasonic waves (for example, it can refer to one of the arrays, such as first selecting the first unit node as the transmitter, and the rest as the receivers. Then switch to the second one as the transmitter, and the rest as the receivers. Then the third one transmits... and traverses all of them. Of course, it does not necessarily follow this order, it can be other orders. Or several unit nodes that are far away and do not interfere with each other can transmit at the same time, and the rest receive, so that The received ultrasonic signal enters the microcontroller circuit after passing through the multiplexer circuit and the signal measurement and amplification circuit, and is converted into a digital quantity for further signal processing, including: calculating the transmission time, amplitude, and frequency change of the ultrasonic pulse from the transmitting unit node to the receiving unit node, solving the distance and angle change from the transmitting unit node to the receiving unit node through the change of transmission time, amplitude, and frequency, setting the distance between the two unit nodes P1 and P2 to L0 when the flexible continuum robot structure is not bent, and the distance to L1 when it is bent, which causes the ultrasonic pulse transmission time change to (L1-L0) / c f , where c f is the propagation speed of an ultrasonic pulse of frequency f in the flexible continuum robot structure; since the piezoelectric transducer has a beam angle when transmitting and receiving ultrasonic waves, when two adjacent nodes are facing each other, the amplitude of the received ultrasonic signal is the strongest, and the relative angle change of the unit node is calculated from the amplitude change. The scanning algorithm between the unit nodes is designed through the microcontroller circuit, and finally the distance and relative angle between any two unit nodes are obtained. Then the complete shape of the flexible continuum robot is fitted through the fitting method, and the complete shape of the flexible continuum robot is sent to the main controller circuit for shape closed-loop control.

[0021] When the robot is in the environmental distance perception mode, the microcontroller circuit selects to control the piezoelectric transducer on the surface of the flexible continuum robot structure to emit ultrasonic pulses perpendicular to the surface of the flexible continuum robot structure. After the ultrasonic pulse is emitted, the piezoelectric transducer is switched to the receiving mode to receive the ultrasonic pulse reflected by the environment. The received ultrasonic signal enters the microcontroller circuit after passing through the multiplexer circuit and the signal measurement and amplification circuit, and is converted into a digital quantity for further signal processing, specifically including: calculating the transmission time, amplitude, and frequency change of the ultrasonic wave from emission to reception, solving the distance from the unit node to the external environment through the change of transmission time, amplitude, and frequency, setting the time for the unit node P3 to emit the ultrasonic pulse to t0, and the time for receiving the ultrasonic pulse reflected by the environment to t1, then the distance between the unit node P3 and the external environment is (t1-t0)*c fe / 2, where c fe is the frequency f e The propagation speed of ultrasonic waves in the environment is determined, and a scanning algorithm is designed through a microcontroller circuit to scan the distance from each unit node to the external environment. The complete shape of the external environment is then fitted through a fitting method, and the complete shape of the external environment is sent to the main controller circuit for obstacle avoidance control of the flexible continuum robot structure.

[0022] When the flexible continuum robot structure is in the environmental contact sensing mode, the microcontroller circuit selects to control the piezoelectric transducer on the surface of the flexible continuum robot structure, applies an AC voltage signal with a frequency of f0 to the piezoelectric transducer, where f0 is the initial resonance frequency of the piezoelectric piece, so that the piezoelectric transducer works in the resonance mode, and measures the change of the current response signal I(t) of the piezoelectric transducer in real time; when the flexible continuum robot structure is not in contact with the environment, the resonance frequency of the flexible continuum robot structure is f0, and the amplitude is the highest at this frequency f0, and the current response signal amplitude is the highest; when the flexible continuum robot structure contacts the environment, the resonance frequency of the piezoelectric transducer changes. At this time, under the excitation of the original f0 AC voltage, the amplitude of the piezoelectric transducer also changes, and the amplitude of the current response signal also changes. The state of contact between the flexible continuum robot structure and the environment and the time of contact are extracted from the current response signal change curve, and sent to the main controller circuit for contact control of the flexible continuum robot structure.

[0023] Beneficial effects:

[0024] 1. Only one system is used, and the flexible continuum robot's own shape, external environment distance, contact status and other information can be sensed through reuse. Compared with the traditional method of using multiple sets of sensor systems, it is simpler and less costly;

[0025] 2. Ultrasonic waves can work in harsh environments such as opaque and turbid liquids (such as blood and sewage), smoke, dust, and strong light. Compared with traditional camera-based vision perception solutions (which cannot be applied to the above harsh environments), ultrasonic waves have better environmental applicability.

[0026] 3. Strong scalability. If the size of the robot changes, there is no need to significantly change the circuit. It only needs to increase a number of piezoelectric transducer nodes accordingly and modify the software scanning algorithm of the microcontroller circuit to make the perception system adapt to the size change. It is flexible, convenient and low-cost.

[0027] 4. Based on the perceived feedback information such as the robot shape, external environment and contact status, a closed-loop control system is constructed to achieve precise control of the flexible robot shape, as well as better environmental obstacle avoidance and contact control, greatly improving the robot's operating accuracy, adaptability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0029] Figure 1 It is a schematic diagram of the flexible continuum robot structure and piezoelectric transducer array layout.

[0030] Figure 2 It is a schematic diagram of a piezoelectric transducer transmitting or receiving ultrasonic waves in different directions.

[0031] Figure 3 It is a block diagram of the shape and environment perception and control system of the flexible continuum robot.

[0032] Explanation of the accompanying drawings: 1: flexible continuum robot structure, 2: flexible robot bending actuator, 3: piezoelectric transducer on the surface of the flexible continuum robot structure, 4: piezoelectric transducer embedded in the flexible continuum robot structure. DETAILED DESCRIPTION

[0033] like Figure 3 As shown, the embodiment of the present invention provides a flexible continuum robot shape and environment perception control system based on a distributed piezoelectric transducer array, including a flexible continuum robot structure 1, a flexible robot bending driver 2, a distributed piezoelectric transducer array, a main controller circuit, a microcontroller circuit, a multiplexer circuit, a power amplifier circuit, and a signal measurement and amplification circuit (the specific flexible continuum robot structure and the piezoelectric transducer array layout are as shown in FIG. Figure 1 shown);

[0034] The distributed piezoelectric transducer array is composed of more than two piezoelectric transducers, and each piezoelectric transducer serves as a unit node;

[0035] Connection relationship such as Figure 3 As shown, the initial end of the arrow is the output side, and the end of the arrow is the input side.

[0036] The flexible continuum robot structure is connected to the flexible robot bending driver through ropes, fluid channels, etc., the distributed piezoelectric transducer array is distributed on the surface of the flexible continuum robot structure and embedded in the flexible continuum robot structure, the main controller circuit is connected to the flexible robot bending driver and the microcontroller circuit through a cable, the electrode of each unit node of the distributed piezoelectric transducer array is connected to the multiplexer through a cable, the multiplexer is connected to the power amplifier and the signal measurement and amplification circuit through a cable, and the microcontroller circuit is connected to the power amplifier and the signal measurement and amplification circuit through a cable.

[0037] The flexible continuum robot structure can be driven by rope drive, pneumatic drive, magnetic drive and other driving modes;

[0038] The main controller circuit parses the received operation commands (robot shape, end motion trajectory, etc.) into setting values ​​of control modes such as shape control, obstacle avoidance control, and contact control according to the task requirements, calculates and synthesizes the output commands through PID, sliding mode, fuzzy and other control algorithms, and obtains the driving commands of the flexible robot (such as rope length, air pressure, magnetic field), and sends the driving commands to the flexible robot bending driver. The flexible robot bending driver generates driving force to drive the flexible continuum robot structure to bend and change its shape.

[0039] The surface and interior of the flexible continuum robot structure are embedded with more than two distributed piezoelectric transducers (i.e., the piezoelectric transducer 3 on the surface of the flexible continuum robot structure and the piezoelectric transducer 4 embedded in the flexible continuum robot structure) for generating and receiving ultrasonic waves. Each piezoelectric transducer is in the shape of a cube, with 6 faces and 3 pairs of electrodes (one pair of electrodes is provided on every 2 opposite faces). By applying AC high-frequency voltage / current signals (V1, V2, V3) to different electrode pairs, the piezoelectric transducer can generate ultrasonic waves in 3 different directions, such as Figure 2 As shown, the microcontroller circuit is used to generate an AC high-frequency signal. After amplifying the voltage and current of the AC high-frequency signal through a power amplifier circuit, a unit node of the piezoelectric transducer array is selected through a multiplexer circuit, and a pair of the three pairs of electrodes of the piezoelectric transducer unit node is selected to apply voltage and current to generate ultrasonic waves in the corresponding direction.

[0040] The flexible continuum robot structure has three modes of shape perception, environmental distance perception and environmental contact perception:

[0041] When the flexible continuum robot structure is in the shape sensing mode, the microcontroller circuit selects to control certain piezoelectric transducers to transmit ultrasonic waves along the surface of the flexible continuum robot structure or inside it, and selects to control the remaining piezoelectric transducers to receive ultrasonic waves. The received ultrasonic signals enter the microcontroller circuit after passing through the multiplexer circuit and the signal measurement and amplification circuit, and are converted into digital quantities for further signal processing, such as calculating the changes in parameters such as the transmission time, amplitude, and frequency of the ultrasonic pulse from the transmitting unit node to the receiving unit node. The distance and angle change from the transmitting unit node to the receiving unit node are solved through the changes in these parameters (for example, the distance between the two unit nodes P1 and P2 is L0 when the flexible continuum robot structure is not bent, and the distance is L1 when it is bent, which causes the ultrasonic pulse transmission time to change to (L1-L0) / c f , where c f is the propagation speed of the ultrasonic pulse of frequency f in the flexible continuum robot structure; in addition, since the piezoelectric transducer has a certain beam angle for transmitting and receiving ultrasonic waves, the energy is strongest in the direction of the axis. When two adjacent unit nodes are facing each other, the amplitude of the received ultrasonic signal is the strongest, so the relative angle change of the unit node can be calculated from the amplitude change). The scanning algorithm between the unit nodes is designed by the microcontroller circuit (such as 1 to 1 transmission and reception of two adjacent unit nodes, or 1 to N transmission and reception of a central node and the other adjacent nodes), and finally the distance and relative angle between any two unit nodes can be obtained, and then the complete shape of the flexible continuum robot is fitted by fitting methods such as polynomials, Bessel, and spline curves, and the complete shape of the flexible continuum robot is sent to the main controller circuit for shape closed-loop control.

[0042] When the robot is in the environmental distance perception mode, the microcontroller circuit selects to control the piezoelectric transducer on the surface of the flexible continuum robot structure to emit ultrasonic pulses perpendicular to the surface of the flexible continuum robot structure. After the ultrasonic pulse is emitted, the piezoelectric transducer is switched to the receiving mode to receive the ultrasonic pulse reflected by the environment. The received ultrasonic signal enters the microcontroller circuit after passing through the multiplexer circuit and the signal measurement and amplification circuit, and is converted into a digital quantity for further signal processing, such as calculating the changes in the transmission time, amplitude, frequency and other parameters of the ultrasonic wave from emission to reception. The distance from the unit node to the external environment is solved through the changes in these parameters (e.g., the time when the unit node P3 emits the ultrasonic pulse is t0, and the time when the ultrasonic pulse reflected by the environment is t1, then its distance from the external environment is (t1-t0)*c fe / 2, where c fe is the frequency f eThe scanning algorithm is designed through the microcontroller circuit to scan the distance from each unit node to the external environment, and then the complete shape of the external environment is fitted through polynomial, Bessel, spline curve and other fitting methods, and the complete shape of the external environment is sent to the main controller circuit for obstacle avoidance control of the flexible continuum robot structure.

[0043] When the flexible continuum robot structure is in the environmental contact sensing mode, the microcontroller circuit selects to control the piezoelectric transducer on the surface of the flexible continuum robot structure, applies an AC voltage signal with a frequency of f0 to the piezoelectric transducer (f0 is the initial resonance frequency of the piezoelectric sheet), makes the piezoelectric transducer work in the resonance mode, and measures the change of the current response signal I(t) of the piezoelectric transducer in real time (t is time). When the flexible continuum robot structure is not in contact with the environment, the resonant frequency of the flexible continuum robot structure is f0, at which the amplitude is the highest and the current response signal amplitude is the highest. When the flexible continuum robot structure contacts the environment, the resonant frequency of the piezoelectric transducer changes, and at this time, its amplitude also changes under the original f0 AC voltage excitation, and the current response signal amplitude also changes accordingly. Therefore, the state of contact between the flexible continuum robot structure and the environment and the time of contact can be extracted from the current response signal change curve, and sent to the main controller circuit for contact control of the flexible continuum robot structure.

[0044] The present invention provides a flexible continuum robot shape and environment perception control system based on a distributed piezoelectric transducer array. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A flexible continuum robot shape and environment perception control system based on a distributed piezoelectric transducer array, characterized in that: It includes a flexible continuum robot structure, a flexible robot bending actuator, a distributed piezoelectric transducer array, a main controller circuit, a microcontroller circuit, a multiplexer circuit, a power amplifier circuit, and a signal measurement and amplification circuit; The flexible continuum robot structure is connected to the flexible robot bending actuator via a rope and a fluid channel; A distributed piezoelectric transducer array is arranged on the surface of the flexible continuum robot structure and inside the flexible continuum robot structure; The main controller circuit is connected to the flexible robot bending driver and the microcontroller circuit via a cable; The distributed piezoelectric transducer array is composed of more than two piezoelectric transducers, and each piezoelectric transducer serves as a unit node; The multiplexer circuit is connected to the power amplifier circuit and the signal measurement and amplification circuit via a cable; The microcontroller circuit is connected to the power amplifier circuit and the signal measurement and amplification circuit through a cable.

2. The system according to claim 1, characterized in that The flexible continuum robot structure is driven by rope, pneumatic or magnetic drive.

3. The system according to claim 2, characterized in that The main controller circuit parses the received operation commands into set values ​​of shape control, obstacle avoidance control, and contact control according to the task requirements, calculates and synthesizes the output commands through the control algorithm, obtains the driving commands of the flexible robot, and sends the driving commands to the flexible robot bending driver. The flexible robot bending driver generates driving force to drive the flexible continuum robot structure to bend and change its shape.

4. The system according to claim 3, characterized in that More than two piezoelectric transducers are respectively embedded on the surface and inside of the flexible continuum robot structure for generating and receiving ultrasonic waves; the more than two piezoelectric transducers form a distributed piezoelectric transducer array.

5. The system according to claim 4, characterized in that Each piezoelectric transducer is in a cubic shape, having 6 faces and 3 pairs of electrodes, wherein a pair of electrodes is provided on the faces opposite to each other of the piezoelectric transducers; The electrodes of the piezoelectric transducer are connected to a multiplexer circuit via cables.

6. The system according to claim 5, characterized in that The microcontroller circuit is used to generate an AC high-frequency signal. After amplifying the voltage and current of the AC high-frequency signal through a power amplifier circuit, a unit node of the distributed piezoelectric transducer array is selected through a multiplexer circuit, and a pair of electrodes in the unit node 3 are selected to apply voltage and current to generate ultrasonic waves in the corresponding direction.

7. The system according to claim 6, characterized in that The flexible continuum robot structure has three working modes: shape perception, environmental distance perception and environmental contact perception.

8. The system according to claim 7, characterized in that When the flexible continuum robot structure is in the shape sensing mode, the microcontroller circuit selects to control a piezoelectric transducer to transmit ultrasonic waves along the surface of the flexible continuum robot structure or transmitted inside, and selects to control the remaining piezoelectric transducers to receive ultrasonic waves. The received ultrasonic signal enters the microcontroller circuit after passing through the multiplexer circuit and the signal measurement and amplification circuit, and is converted into a digital quantity for further signal processing, specifically including: calculating the transmission time, amplitude, and frequency change of the ultrasonic pulse from the transmitting unit node to the receiving unit node, solving the distance and angle change from the transmitting unit node to the receiving unit node through the change of transmission time, amplitude, and frequency, setting the distance between the two unit nodes P1 and P2 to L0 when the flexible continuum robot structure is not bent, and the distance to L1 when it is bent, thereby causing the ultrasonic pulse transmission time to change to (L1-L0) / c f , where c f is the propagation speed of an ultrasonic pulse of frequency f in the flexible continuum robot structure; since the piezoelectric transducer has a beam angle when transmitting and receiving ultrasonic waves, when two adjacent nodes are facing each other, the amplitude of the received ultrasonic signal is the strongest, and the relative angle change of the unit node is calculated from the amplitude change. The scanning algorithm between the unit nodes is designed through the microcontroller circuit, and finally the distance and relative angle between any two unit nodes are obtained. Then the complete shape of the flexible continuum robot is fitted through the fitting method, and the complete shape of the flexible continuum robot is sent to the main controller circuit for shape closed-loop control.

9. The system according to claim 8, characterized in that When the robot is in the environmental distance perception mode, the microcontroller circuit selects to control the piezoelectric transducer on the surface of the flexible continuum robot structure to emit ultrasonic pulses perpendicular to the surface of the flexible continuum robot structure. After the ultrasonic pulse is emitted, the piezoelectric transducer is switched to the receiving mode to receive the ultrasonic pulse reflected by the environment. The received ultrasonic signal enters the microcontroller circuit after passing through the multiplexer circuit and the signal measurement and amplification circuit, and is converted into a digital quantity for further signal processing, specifically including: calculating the transmission time, amplitude, and frequency change of the ultrasonic wave from emission to reception, solving the distance from the unit node to the external environment through the change of transmission time, amplitude, and frequency, setting the time for the unit node P3 to emit the ultrasonic pulse to t0, and the time for receiving the ultrasonic pulse reflected by the environment to t1, then the distance between the unit node P3 and the external environment is (t1-t0)*c fe / 2, where c fe is the frequency f e The propagation speed of ultrasonic waves in the environment is determined, and a scanning algorithm is designed through a microcontroller circuit to scan the distance from each unit node to the external environment. The complete shape of the external environment is then fitted through a fitting method, and the complete shape of the external environment is sent to the main controller circuit for obstacle avoidance control of the flexible continuum robot structure.

10. The system according to claim 9, characterized in that When the flexible continuum robot structure is in the environmental contact sensing mode, the microcontroller circuit selects to control the piezoelectric transducer on the surface of the flexible continuum robot structure, applies an AC voltage signal with a frequency of f0 to the piezoelectric transducer, where f0 is the initial resonance frequency of the piezoelectric piece, so that the piezoelectric transducer works in the resonance mode, and measures the change of the current response signal I(t) of the piezoelectric transducer in real time; when the flexible continuum robot structure is not in contact with the environment, the resonance frequency of the flexible continuum robot structure is f0, and the amplitude is the highest at this frequency f0, and the current response signal amplitude is the highest; when the flexible continuum robot structure contacts the environment, the resonance frequency of the piezoelectric transducer changes. At this time, under the excitation of the original f0 AC voltage, the amplitude of the piezoelectric transducer also changes, and the amplitude of the current response signal also changes. The state of contact between the flexible continuum robot structure and the environment and the time of contact are extracted from the current response signal change curve, and sent to the main controller circuit for contact control of the flexible continuum robot structure.

Images