A compliant control end face ratchet active rotation locking mechanism and a compliant control method thereof

Abstract

The application discloses a compliant control end face ratchet active rotation locking mechanism and a compliant control method thereof, one side of the fixed ratchet and the sliding ratchet oppositely is distributed with end face ratchets, which are used for limiting the rotation direction when being engaged with each other, and the center of the fixed ratchet and the sliding ratchet is provided with a round hole; the center of the motor has a hole, and the installation surface is located at both sides of the motor, one side of which is matched with an output connecting rod, and the other side is matched with a sleeve connecting rod, and the output connecting rod and the sleeve connecting rod are connected through the motor to form a rotating mechanism; the sleeve connecting rod is provided with square sliding grooves on both sides, a circular through hole is arranged on the upper surface, and a round hole is arranged in the center of the bottom; the end face of the end cover is provided with a protrusion matched with a groove on the end face of the sleeve connecting rod to realize fixation. The application has the advantages of simple structure, fast response speed, and the effect of compliant control and locking rotation can be realized under the limitation of small size.

Description

Technical Field

[0001] This invention belongs to the field of robotics technology, and in particular relates to a compliant control end face ratchet active rotation locking mechanism and its compliant control method. Background Technology

[0002] Motor-driven joint rotation is a crucial design element in robotics. Different task objectives require varying joint stiffness, which can be achieved through compliant control algorithms. Joint locking mechanisms are a common mechanical design used to lock or release joints when needed, saving energy and reducing joint wear. These mechanisms are widely used in engineering, medical equipment, and sports equipment. Currently, most common technologies utilize friction, ball joints, gears, or hydraulic mechanisms for locking. Friction locking leads to wear on friction components over time, high energy consumption, and low precision; ball joint locking has limited reliability, is prone to gaps or loosening with long-term use, and lacks flexibility; gear locking is complex, occupies a large space, and has high design and manufacturing costs; hydraulic systems have high manufacturing and maintenance costs, are complex, pose a risk of oil leakage affecting reliability and environmental safety, and are heavy, making them unsuitable for applications with high lightweight requirements. Summary of the Invention

[0003] The purpose of this invention is to provide a compliant control end face ratchet active rotation locking mechanism and its compliant control method, which realizes the active compliant control rotation and locking function of the joint and reduces the space occupancy rate.

[0004] To achieve the objective of this invention, on one hand, this invention provides a compliant control end-face ratchet active rotation locking mechanism. The fixed ratchet and the sliding ratchet have end-face ratchets distributed on opposite sides to limit directional rotation when they mesh with each other. The fixed ratchet and the sliding ratchet have a circular hole at their center. The motor has a hole at its center and mounting surfaces on both sides of itself. One side engages with the output connecting rod, and the other side engages with the sleeve connecting rod. The output connecting rod and the sleeve connecting rod form a rotation mechanism through the motor.

[0005] The sleeve connecting rod has square sliding grooves on both sides, a circular through hole on the upper surface, and a circular hole at the center of the bottom.

[0006] The end cap has a protrusion on its end face, and a circular through hole is opened in the center of the protrusion, which cooperates with the groove on the end face of the sleeve connecting rod to achieve fixation.

[0007] When the arc-shaped end face of the sliding ratchet meshes with the arc-shaped end face of the fixed ratchet, a gap is left between the center of the sliding ratchet and the fixed ratchet for fixing the shape memory alloy spring.

[0008] One end of the first memory alloy spring is fixed at the circular hole in the center of the end cap, and the other end is fixed at the circular hole in the center of the sliding ratchet; one end of the second memory alloy spring is fixed at the circular hole in the center of the sliding ratchet, and the other end is fixed at the circular hole in the center of the fixed ratchet, ensuring that the end face ratchets of the sliding ratchet and the fixed ratchet can mesh with each other when the memory alloy spring contracts.

[0009] When the first memory alloy spring is energized, it contracts, and the end face ratchet teeth on the surfaces of the fixed ratchet and the sliding ratchet separate, allowing the shaft to rotate freely. When the second memory alloy spring is energized, it contracts, and the end face ratchet teeth on the surfaces of the fixed ratchet and the sliding ratchet engage, restricting the rotation of the shaft in the direction of force.

[0010] The output connecting rod has a protruding shaft and a small hole at its center. During installation, the protruding shaft passes through the center of the motor and the bottom hole of the sleeve connecting rod, and mates with the fixed ratchet mounting surface.

[0011] The protruding shaft end has a groove that engages with the protrusion in the fixed ratchet mounting groove to achieve fixation.

[0012] The sliding ratchet moves axially within the sleeve by engaging with the sliding groove of the sleeve connecting rod via square sliders on both sides.

[0013] On the other hand, the present invention also provides a compliant control method for a compliant control end face ratchet active rotation locking mechanism, comprising the following steps:

[0014] Step 1: Obtain angle and torque data through real-time feedback from the motor sensor;

[0015] Step 2: Input the angle data and the torque data into the admittance controller to obtain the desired angle error value;

[0016] Step 3: Input the calculated actual target angle into the PID position controller to complete the position control of the motor.

[0017] Compared with the prior art, the significant progress of the present invention is as follows: (1) The active rotation locking mechanism provided by the present invention has a compact structure and low space occupancy rate; and is easy to install, simple to use, and more portable; (2) The present invention drives the slider to move in two directions through two memory alloy springs to realize the engagement and disengagement of ratchet, thereby achieving the purpose of locking rotation and saving energy; (3) The present invention has a simple structure and fast response speed, and can achieve compliant control and locking rotation effect under small size constraints.

[0018] To more clearly illustrate the functional characteristics and structural parameters of the present invention, further explanation is provided below in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0020] Figure 1 This is a composite diagram of the present invention;

[0021] Figure 2 This is an exploded structural diagram of the present invention;

[0022] Figure 3 This is a schematic diagram of the output linkage structure of the present invention;

[0023] Figure 4 This is a schematic diagram of the motor structure of the present invention;

[0024] Figure 5 This is a schematic diagram of the sleeve connecting rod structure of the present invention;

[0025] Figure 6 This is a schematic diagram of the fixed ratchet structure of the present invention;

[0026] Figure 7 This is a schematic diagram of the sliding ratchet structure of the present invention;

[0027] Figure 8 This is a schematic diagram of the end cap structure of the present invention;

[0028] Figure 9 This is a block diagram of the compliance control method of the present invention.

[0029] The attached diagram is labeled as follows: 1-output link, 2-motor, 3-sleeve link, 4-fixed ratchet, 5-sliding ratchet, 6-end cap. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The present invention provides a compliant control end face ratchet active rotation locking mechanism, combined with Figure 1 and Figure 2 The fixed ratchet 4 and the sliding ratchet 5 have end face ratchet teeth distributed on opposite sides to limit directional rotation when they mesh with each other. The fixed ratchet 4 and the sliding ratchet 5 have a circular hole at their center.

[0032] Combination Figure 4 The hollow motor 2 is used to protrude the shaft through the output connecting rod. The motor mounting surface is located on both sides of itself, which are respectively connected to the output connecting rod and the sleeve connecting rod. The entire joint mechanism is rotated by the rotation of the motor. One side is engaged with the output connecting rod 1, and the other side is engaged with the sleeve connecting rod 3. The output connecting rod 1 and the sleeve connecting rod 3 form a rotating mechanism through the motor.

[0033] Combination Figure 5 The sleeve connecting rod 3 has square sliding grooves on both sides, a circular through hole on the upper surface, and a circular hole at the center of the bottom. Figure 8 The end cap 6 has a protrusion on its end face, and a circular through hole is opened in the center of the protrusion for fixing one end of the first memory alloy spring. It also serves as a lead wire and cooperates with the groove on the end face of the sleeve connecting rod 3 to achieve fixation.

[0034] When the sliding ratchet 5 engages with the fixed ratchet 4, a gap is left between the center of the sliding ratchet 5 and the fixed ratchet 4 to fix the shape memory alloy spring.

[0035] Combination Figure 6 The fixed ratchet 4 has an arc-shaped end face ratchet on its surface, which locks the ratchet when it engages with the end face ratchet of the sliding ratchet 5. One end of the first shape memory alloy spring is fixed to the circular hole in the center of the end cap 6, and the other end is fixed to the circular hole in the center of the sliding ratchet 5. One end of the second shape memory alloy spring is fixed to the circular hole in the center of the sliding ratchet 5, and the other end is fixed to the circular hole in the center of the fixed ratchet 4, ensuring that the end face ratchets on the surfaces of the sliding ratchet 5 and the fixed ratchet 4 can engage with each other when the shape memory alloy spring is contracted.

[0036] When the first memory alloy spring is energized, it contracts, and the end face ratchet teeth on the surfaces of the fixed ratchet 4 and the sliding ratchet 5 separate, allowing the shaft to rotate freely. When the second memory alloy spring is energized, it contracts, and the end face ratchet teeth on the surfaces of the fixed ratchet 4 and the sliding ratchet 5 engage, restricting the rotation of the shaft in the direction of force.

[0037] Combination Figure 3 The output connecting rod 1 has a protruding shaft and a small hole at its center. During installation, the protruding shaft passes through the center of the motor 2 and the bottom hole of the sleeve connecting rod 3, and mates with the mounting surface of the fixed ratchet 4.

[0038] The protruding shaft end has a groove that engages with the protrusion in the mounting groove of the fixing ratchet 3 to achieve fixation.

[0039] Combination Figure 7Furthermore, the sliding ratchet 5 has an arc-shaped end face ratchet on its surface and a memory alloy spring fixing hole in its center. The sliding ratchet 5 cooperates with the sliding groove of the sleeve connecting rod 3 through the square sliders on both sides to achieve axial movement within the sleeve.

[0040] This invention also includes a compliant control method for a compliant control end-face ratchet active rotation locking mechanism, combined with... Figure 9 This includes the following steps:

[0041] Step 1: Obtain angle and torque data through real-time feedback from the motor sensor;

[0042] Step 2: Input the angle data and the torque data into the admittance controller to obtain the desired angle error value;

[0043] The dynamic model of the admittance controller is as follows:

[0044]

[0045] Where M is the mass parameter, describing the system's inertia; B is the damping parameter, describing the system's damping characteristics; K is the stiffness parameter, describing the system's elastic characteristics; θ, These represent joint angle, joint angular velocity, and joint angular acceleration, respectively; T is the external torque of the joint.

[0046] Discretize the above equation according to the time interval Δt, rewrite the admittance-related parameters, and determine the discrete form model of the admittance controller:

[0047]

[0048] Where k and k-1 represent the nth discrete time step, With Δθ k These represent the angular acceleration, angular velocity, and angular error values ​​at time k, respectively.

[0049] The error value is generated by the external torque T of the joint, i.e., the actual target angle θ. k From the perspective of original expectations The relationship is as follows:

[0050]

[0051] Step 3: Input the calculated actual target angle into the PID position controller to complete the position control of the motor.

[0052] Example

[0053] A driving method for a compliant control face ratchet active rotation locking mechanism is as follows:

[0054] Shape memory alloys are driven by electric current, and the heat comes from the thermal effect of the current. The relationship between the current, the temperature of the shape memory alloy spring, and the ambient temperature is shown in the following model:

[0055]

[0056] Where I is the current magnitude, R is the shape memory alloy resistance, h is the convective heat transfer coefficient, T1 is the shape memory alloy temperature, T0 is the ambient temperature, T2 is the metal wire temperature, and R... λ This represents the contact thermal resistance between the shape memory alloy and the metal wire. The shape memory alloy used has a phase transition temperature of 60℃. The required driving current is calculated based on the ambient temperature using a model, enabling real-time correction under different ambient temperatures to ensure the performance of the shape memory alloy.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A compliant control end-face ratchet active rotation locking mechanism, characterized in that, The fixed ratchet (4) and the sliding ratchet (5) have end face ratchet teeth distributed on opposite sides, which are used to restrict the rotation of the direction when they mesh with each other. The fixed ratchet (4) and the sliding ratchet (5) have a circular hole in the center. The motor (2) has a hole in the center and the mounting surfaces are located on both sides of itself. One side is engaged with the output connecting rod (1) and the other side is engaged with the sleeve connecting rod (3). The output connecting rod (1) and the sleeve connecting rod (3) form a rotating mechanism through the motor. The sleeve connecting rod (3) has square sliding grooves on both sides, a circular through hole on the upper surface, and a circular hole at the center of the bottom. The end cap (6) has a protrusion on its end face, and a circular through hole is opened in the center of the protrusion, which cooperates with the groove on the end face of the sleeve connecting rod (3) to achieve fixation; When the arc-shaped end face ratchet of the sliding ratchet (5) meshes with the arc-shaped end face ratchet of the fixed ratchet (4), there is a gap between the center of the sliding ratchet (5) and the fixed ratchet (4) for fixing the memory alloy spring. One end of the first memory alloy spring is fixed at the round hole in the center of the end cap (6), and the other end is fixed at the round hole in the center of the sliding ratchet (5); one end of the second memory alloy spring is fixed at the round hole in the center of the sliding ratchet (5), and the other end is fixed at the round hole in the center of the fixed ratchet (4), and ensures that the end face ratchets of the sliding ratchet (5) and the fixed ratchet (4) can mesh with each other when the memory alloy spring contracts; When the first memory alloy spring is energized, the first memory alloy spring contracts, and the end face ratchet of the fixed ratchet (4) and the sliding ratchet (5) separates, allowing the shaft to rotate freely; when the second memory alloy spring is energized, the second memory alloy spring contracts, and the end face ratchet of the fixed ratchet (4) and the sliding ratchet (5) meshes, restricting the rotation of the shaft in the direction of force. The output connecting rod (1) has a protruding shaft and a small hole at its center. During installation, the protruding shaft passes through the center of the motor (2) and the bottom hole of the sleeve connecting rod (3), and engages with the mounting surface of the fixed ratchet (4). The protruding shaft end has a groove that engages with the protrusion in the mounting groove of the fixing ratchet (3) to achieve fixation; The sliding ratchet (5) engages with the groove of the sleeve connecting rod (3) through the square sliders on both sides, thereby achieving axial movement within the sleeve.

2. A compliant control method based on the compliant control end face ratchet active rotation locking mechanism according to claim 1, characterized in that, Includes the following steps: Step 1: Obtain angle and torque data through real-time feedback from the motor sensor; Step 2: Input the angle data and the torque data into the admittance controller to obtain the desired angle error value; Step 3: Input the calculated actual target angle into the PID position controller to complete the position control of the motor; The dynamic model of the admittance controller is as follows: ； in, The mass parameter describes the inertia of the system; These are damping parameters, describing the damping characteristics of the system. The stiffness parameter describes the elastic properties of the system. These are joint angle, joint angular velocity, and joint angular acceleration, respectively. External torque of the joint; Determine the discrete form model of the admittance controller: ； ； ； in, Indicates time interval, and Indicates the nth discrete time step. , and They represent Angular acceleration, angular velocity, and angular error values ​​at any given time; From the perspective of actual goals From the perspective of original expectations The relationship is shown in the following formula: 。

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