Single-hall bidirectional rotary input device and direction identification method thereof

Abstract

The application belongs to the technical field of magnetic sensing, and particularly relates to a single-Hall bidirectional rotary input device and a direction recognition method thereof. The device comprises a rotary operating member, an end face cam, a driven bracket, a magnet, a single linear Hall sensor and a processor. The end face cam has a plurality of positioning areas arranged along a circumference, and the stable platforms of the positioning areas have at least three different heights and are repeatedly arranged in a predetermined cyclic sequence in the circumferential direction. The driven bracket can only move in the axial direction and is linked with the positioning areas in sequence when the rotary operating member rotates. The linear Hall sensor detects the change in the magnetic field strength generated by the axial movement of the magnet with the driven bracket. The processor maps the Hall signal into at least three stable states, detects the migration between the states, and determines the rotary direction according to the migration sequence. The application can realize bidirectional rotary direction recognition using a single linear Hall sensor, has a compact structure, low cost and high reliability, and the direction determination is not dependent on the rotary speed.

Description

Technical Field

[0001] This invention belongs to the field of magnetic sensing technology, specifically a single Hall bidirectional rotary input device and its direction recognition method. Background Technology

[0002] Rotary encoders are widely used in keyboard knobs, volume controls, menu navigation, and industrial control. Common mechanical encoders typically use two sets of phase-shifted contacts to generate quadrature signals, determining the direction of rotation by the phase difference between the two signals. However, mechanical encoders suffer from contact wear, leading to decreased reliability over long-term use. Photoelectric encoders usually require both light-emitting and receiving devices, resulting in complex structures and higher costs. Magnetic encoders may employ multiple Hall effect sensors, two-dimensional or three-dimensional magnetic sensors, or dedicated chips with angle calculation capabilities; however, these solutions suffer from a large number of components, a large board space footprint, or high costs.

[0003] In devices such as linear Hall effect magnetic axis keyboards, the printed circuit board (PCB) already has a linear Hall effect detection channel that samples the axial distance of the magnet. If only a single continuous ramp is set, so that the magnet completes one axial reciprocating motion when the knob rotates one revolution, a single Hall effect channel can only observe the change in axial position over time. Since the knob is driven by hand and the rotation speed is not constant, the signal changes generated by the rapid passage of the ramp and the signal changes generated by the slow passage of the ramp may overlap. Relying solely on the signal slope, rate of change, or delay shielding cannot reliably determine the direction of rotation across the entire speed range.

[0004] Therefore, it is necessary to provide an input device and its direction recognition method that can reliably identify bidirectional rotation direction using a single linear Hall sensor. Summary of the Invention

[0005] This invention provides a single Hall effect bidirectional rotary input device and its direction recognition method, which solves the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A single Hall effect bidirectional rotary input device, comprising:

[0008] Rotating operating element;

[0009] An end face cam is connected to the rotary actuator and rotates with the rotary actuator about an axis. The end face cam has a plurality of positioning areas arranged in a circumferential direction. Each positioning area includes a stabilizing platform. The height of the stabilizing platform is one of at least three different heights, which are repeated in a predetermined cyclic sequence along the circumferential direction.

[0010] The driven bracket is constrained to move only along the axis direction and is used to sequentially engage with the plurality of positioning areas during the rotation of the rotating operating member.

[0011] The magnet is fixedly mounted on the driven support;

[0012] A single linear Hall sensor is positioned within the magnetic field range of the magnet to detect changes in magnetic field strength generated by the magnet moving axially with the driven support.

[0013] The processor, connected to the linear Hall sensor, is configured to: map the output signal of the linear Hall sensor to at least three stable states corresponding to the at least three different heights; detect transitions between the stable states; and determine the rotation direction of the rotating actuator according to the order of the transitions.

[0014] As a preferred embodiment of the present invention, the device further includes an elastic element that applies a preload force toward the end face cam to the driven bracket, so that one end of the driven bracket abuts against the end face of the end face cam.

[0015] As a preferred embodiment of the present invention, the device further includes a PCB board, with the magnet and the single linear Hall sensor disposed on opposite sides of the PCB board.

[0016] As a preferred embodiment of the present invention, the number of the plurality of positioning areas is 3m, where m is an integer greater than or equal to 2; every three adjacent positioning areas constitute an encoding cycle, and the three positioning areas in each encoding cycle have a first axial height, a second axial height and a third axial height, respectively, and the first axial height, the second axial height and the third axial height increase or decrease along the circumferential direction.

[0017] In a preferred embodiment of the present invention, m is 4.

[0018] As a preferred embodiment of the present invention, a transition surface inclined relative to the circumferential direction is provided between adjacent stable platforms.

[0019] As a preferred embodiment of the present invention, the device further includes a positioning plate, the driven bracket is slidably mounted on the positioning plate, the positioning plate is fixedly connected to the PCB board, and the bottom cross section of the driven bracket is polygonal.

[0020] As a preferred embodiment of the present invention, the device further includes a support housing, which is fixedly mounted on the positioning plate. The rotating operating member is disposed above the support housing, and the end face cam is disposed inside the support housing. The rotating operating member and the end face cam are connected by a connecting shaft, which is rotatably mounted on the top of the support housing and passes through the support housing.

[0021] The present invention also provides a method for orientation recognition using the above-mentioned single-Hall bidirectional rotary input device, comprising:

[0022] The detection signal output by the single linear Hall sensor, which varies with the axial position of the magnet, is acquired.

[0023] The detection signal is mapped to at least three discrete states corresponding to at least three axial positions based on at least two decision boundaries;

[0024] The stability of the candidate discrete states obtained by mapping is verified to obtain the current stable state;

[0025] Compare the current stable state with the previous stable state;

[0026] When the current stable state migrates relative to the previous stable state along the predetermined cyclic sequence, it is determined to be the first rotation direction; when the current stable state migrates relative to the previous stable state along the reverse of the predetermined cyclic sequence, it is determined to be the second rotation direction.

[0027] As a preferred embodiment of the present invention, the stability verification includes: performing median calculation on multiple consecutive sampled values; obtaining candidate discrete states using a decision boundary with a hysteresis region; updating the current stable state when the candidate discrete state appears consecutively a predetermined number of times; and not outputting a step event for transition region samples that do not meet the stability verification conditions.

[0028] As a preferred embodiment of the present invention, the method further includes: acquiring statistical values ​​of detection signals at the at least three axial positions during the calibration stroke, and setting at least two judgment boundaries based on the boundaries between adjacent statistical values ​​to compensate for the tolerances of the magnet, the linear Hall sensor, the assembly spacing, and the cam structure.

[0029] The present invention has the following advantages:

[0030] 1. Bidirectional rotation direction recognition and step event output can be achieved using a single linear Hall sensor, which makes it easy to reuse the existing Hall sampling hardware in devices such as magnetic axis keyboards, without the need to add additional sensors or dedicated magnetic angle chips, thus reducing the number of devices and costs.

[0031] 2. A cyclic position code is formed using three or more axial heights. The orientation is determined by the order of state transitions rather than the speed of signal change. It does not rely on manual rotation speed and can reliably identify the rotation direction across the entire speed range.

[0032] 3. The stabilizing platform of the end face cam provides both a clear mechanical positioning feel and a stable Hall sampling window, improving the user's operating experience;

[0033] 4. The Hall sensor can be set on the back of the PCB board, and the magnet is set on the front of the PCB board. The structure is compact, and the magnet has no electrical connection and contact wear, so the reliability is high.

[0034] 5. Through algorithms such as calibration, hysteresis determination, and continuous state confirmation, the tolerance to manufacturing tolerances, electrical noise, and transition zone sampling can be effectively improved. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the overall structure of a single Hall bidirectional rotary input device according to the present invention. Figure 1 ;

[0037] Figure 2 This is a schematic diagram of the overall structure of a single Hall bidirectional rotary input device according to the present invention. Figure 2 ;

[0038] Figure 3 This is a schematic diagram of the connection structure of the connecting shaft and the end face cam of a single Hall bidirectional rotary input device according to the present invention;

[0039] Figure 4 This is a schematic diagram of the end face cam structure of a single Hall bidirectional rotary input device according to the present invention;

[0040] Figure 5 This is a schematic cross-sectional view of the overall structure of a single Hall bidirectional rotary input device according to the present invention;

[0041] Figure 6 This is a schematic diagram of the driven support structure of a single Hall bidirectional rotary input device according to the present invention;

[0042] Figure 7 This is a schematic cross-sectional view of the driven support structure of a single Hall bidirectional rotary input device according to the present invention;

[0043] Figure 8 This is a top view schematic diagram of the end face cam of a single Hall bidirectional rotary input device according to the present invention;

[0044] Figure 9 This is a schematic diagram of the unfolded outline and state sequence of the end face cam of a single Hall bidirectional rotary input device according to the present invention;

[0045] Figure 10 This is a schematic diagram illustrating the three-state orientation recognition relationship of a single Hall bidirectional rotary input device according to the present invention;

[0046] Figure 11 This is a structural block diagram of an identification method for a single Hall effect bidirectional rotary input device according to the present invention.

[0047] In the diagram: 1. PCB board; 2. Pad post; 3. Positioning plate; 4. Knob; 5. Support housing; 6. Driven bracket; 7. Compression spring; 8. End face cam; 81. First cam platform; 82. Second cam platform; 83. Third cam platform; 9. Hall sensor; 10. Connecting shaft; 11. Follower head; 12. Magnet. Detailed Implementation

[0048] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0049] It should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0050] Example 1: Overall Structure of a Single Hall Bidirectional Rotary Input Device

[0051] Please see Figures 1 to 7 This embodiment provides a single Hall bidirectional rotary input device, including a rotary operating component, an end face cam 8, a driven bracket 6, a magnet 12, a single linear Hall sensor 9, and a processor.

[0052] like Figure 1 and Figure 2As shown, the rotating operating component is a knob 4, located at the top of the device, for manual operation by the user to input rotation commands. A connecting shaft 10 is provided between the knob 4 and the end face cam 8. One end of the connecting shaft 10 is connected to the knob 4, and the other end is connected to the end face cam 8. The connecting shaft 10 and the knob 4, as well as the connecting shaft 10 and the end face cam 8, can be fixedly connected by means of snap-fit, key connection, welding, or integral molding. When the user rotates the knob 4, the end face cam 8 is driven to rotate synchronously around an axis through the connecting shaft 10.

[0053] Please see Figure 3 and Figure 4 The end-face cam 8 is disc-shaped, with its lower end face serving as the cam working surface. The end-face cam 8 has multiple positioning areas arranged circumferentially, each positioning area including a stabilizing platform. The height of the stabilizing platform is one of at least three different heights, and these at least three different heights are repeatedly arranged circumferentially in a predetermined cyclic sequence. In this embodiment, as... Figure 4 and Figure 8 As shown, the end face cam 8 is provided with a first cam platform 81, a second cam platform 82, and a third cam platform 83, corresponding to the first axial height, the second axial height, and the third axial height, respectively. The three heights are arranged in a cyclical order of P1→P2→P3→P1 along the circumferential direction. A transition surface inclined relative to the circumferential direction is provided between adjacent stabilizing platforms, so that the follower head 11 can smoothly transition between adjacent stabilizing platforms.

[0054] Please see Figure 5 and Figure 6 The driven bracket 6 is constrained to move only along the axial direction (i.e., the up-down direction), and is used to sequentially engage with the plurality of positioning areas during the rotation of the knob 4. Specifically, the driven bracket 6 is slidably mounted on the positioning plate 3, and the positioning plate 3 is fixedly connected to the PCB board 1 by a pad 2. The bottom cross-section of the driven bracket 6 is polygonal (e.g., quadrilateral, hexagonal, etc.), and the positioning plate 3 has a polygonal hole that mates with it, thereby restricting the rotational freedom of the driven bracket 6 around the axial direction, so that it can only slide axially.

[0055] like Figure 5 As shown, the driven bracket 6 has an inverted L-shaped structure, with its long side slidably connected to the positioning plate 3, and a follower head 11 mounted on its short side. The follower head 11 is used to abut against the end face of the end face cam 8. When the end face cam 8 rotates, the follower head 11 passes through stable platforms of different heights in sequence, thereby driving the driven bracket 6 to move axially. The follower head 11 can be in the form of a ball head, roller, arc head, or slider, etc., to reduce friction with the end face of the cam.

[0056] The device also includes an elastic element that applies a preload force to the driven bracket 6 toward the end face cam 8, ensuring that the follower head 11 of the driven bracket 6 remains in contact with the end face cam 8. Figure 5 and Figure 7 As shown, in this embodiment, the elastic element is a compression spring 7, which is sleeved on the long side structure of the driven bracket 6. One end of the compression spring 7 abuts against the short side structure of the driven bracket 6, and the other end abuts against the positioning plate 3, applying an upward elastic force to the driven bracket 6. In other embodiments, the elastic element can also be implemented by means of leaf spring, elastic arm, or magnetic preload.

[0057] like Figure 5 As shown, magnet 12 is fixedly mounted on the driven bracket 6. In this embodiment, magnet 12 is an axially magnetized permanent magnet, fixed to the lower end of the long side structure of the driven bracket 6, with magnetic poles arranged in the vertical direction. The PCB board 1 is disposed below the driven bracket 6, and magnet 12 is located above the front surface of the PCB board 1.

[0058] A single linear Hall sensor 9 is disposed on the back (i.e., below) of the PCB board 1, within the magnetic field range of the magnet 12. When the magnet 12 moves axially with the driven bracket 6, the magnetic field strength at the linear Hall sensor 9 changes, and the linear Hall sensor 9 outputs an electrical signal corresponding to the magnetic field strength.

[0059] The processor is connected to the linear Hall sensor 9 and is configured to: map the output signal of the linear Hall sensor 9 to at least three stable states corresponding to at least three different heights; detect the transitions between the stable states; and determine the rotation direction of the knob 4 according to the order of the transitions. The processor can be mounted on the PCB board 1 or in an external control circuit.

[0060] Please continue reading. Figure 5 The device further includes a support housing 5, which is fixedly mounted on the positioning plate 3. A knob 4 is positioned above the support housing 5, and an end-face cam 8 is located inside the support housing 5. A connecting shaft 10 is rotatably mounted on the top of the support housing 5 and passes through it, transmitting the rotational movement of the knob 4 to the internal end-face cam 8.

[0061] Example 2: Number of Positioning Zones and Encoding Cycle of End Face Cam

[0062] Please see Figure 8 and Figure 9In this embodiment, the number of multiple positioning areas of the end face cam 8 is 3m, where m is an integer greater than or equal to 2. Every three adjacent positioning areas constitute an encoding cycle. The three positioning areas in each encoding cycle have a first axial height, a second axial height, and a third axial height, respectively, and they increase or decrease along the circumferential direction.

[0063] In a preferred embodiment, m=4, meaning 12 positioning zones are set in one revolution, repeating 4 sets in the order P3→P2→P1 (or P1→P2→P3). Thus, the end face cam 8 has 12 mechanical positioning positions in one revolution, corresponding to 12 gears, retaining a ratchet-like gear shift feel while allowing bidirectional rotation to be determined using a single-channel linear Hall effect sensor. It should be noted that the core of this invention is not to divide the magnet travel into 12 absolute heights, but rather to use three heights to form a cyclic code, with the Hall electrical state only cycling through the three states P1, P2, and P3.

[0064] Example 3: Three-State Direction Recognition Method

[0065] Please see Figures 9 to 11 The present invention also provides a method for orientation recognition using the above-mentioned single Hall bidirectional rotary input device, comprising the following steps:

[0066] S1: Signal Acquisition. The detection signal output by the single linear Hall sensor 9 is continuously sampled using an analog-to-digital converter (ADC), and the detection signal varies with the axial position of the magnet 12. Preferably, median calculation (e.g., 5-point median filtering) is first performed on multiple consecutive sampled values ​​to suppress impulse noise.

[0067] S2: State Mapping. The detected signal is mapped to at least three discrete states corresponding to at least three axial positions based on at least two decision boundaries. The decision boundaries can be set based on the measured ADC center values ​​of three stable platforms, and the decision boundaries have hysteresis regions, i.e., different thresholds are used for entering and exiting a certain state to improve noise immunity.

[0068] For example, such as Figure 10 As shown, the Hall ADC value is mapped to three stable states P1, P2, and P3. These stable states correspond to the first cam platform 81, the second cam platform 82, and the third cam platform 83 of the end face cam 8, respectively.

[0069] S3: Stability Verification. The stability of the mapped candidate discrete states is verified to obtain the current stable state. Specifically, the current stable state is updated only when the candidate discrete state appears consecutively a predetermined number of times (e.g., 3 consecutive samples). For transition region samples that do not meet the stability verification conditions, no step event is output.

[0070] S4: Direction Determination. The current stable state is compared with the previous stable state. When the current stable state migrates in the predetermined cyclic sequence relative to the previous stable state, it is determined to be a first rotation direction (e.g., clockwise); when the current stable state migrates in the reverse order relative to the previous stable state, it is determined to be a second rotation direction (e.g., counterclockwise).

[0071] by Figure 9 and Figure 10 Taking the three-state loop P1→P2→P3→P1 as an example, when rotating in one direction, the effective state transitions are P3→P2, P2→P1, and P1→P3 in sequence; when rotating in the opposite direction, the effective state transitions are P3→P1, P1→P2, and P2→P3 in sequence. Each time an adjacent state transition is confirmed, a relative step event with direction is output.

[0072] Example 4: Calibration Method

[0073] In actual production, due to factors such as differences in the magnetic properties of the magnet 12, differences in the sensitivity of the linear Hall sensor 9, assembly spacing tolerances, and machining tolerances of the end face cam 8, the center values ​​of the Hall ADC in different individual devices may deviate. Therefore, the method of this invention further includes a calibration step:

[0074] During the factory calibration process, the knob 4 is rotated one revolution, causing the driven bracket 6 to sequentially pass through each stabilizing platform of the end face cam 8. Statistical values ​​(e.g., average or median) of the detection signals at at least three axial positions (corresponding to three heights) are collected, and at least two judgment boundaries are set based on the boundaries between adjacent statistical values. Calibration effectively compensates for the influence of the various tolerances mentioned above, ensuring the accuracy of the state mapping.

[0075] Brief description of working principle

[0076] The core principle of this invention lies in converting the circumferential motion of the rotating operating component into discrete axial displacements of the driven support 6 and the magnet 12 via the end-face cam 8. The end-face cam 8 has at least three stable platforms of different heights arranged along its circumference, with these three heights repeating in a fixed cyclic order. A single linear Hall sensor 9 only needs to distinguish the magnetic field strength corresponding to the three height states. The processor identifies the rotation direction by detecting the transition sequence between consecutive states and outputs a relative step event. Since the direction determination is based on the order of state transitions rather than the signal change rate, it can operate reliably at any rotational speed.

[0077] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

[0078] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A single Hall effect bidirectional rotary input device, characterized in that, include: Rotating operating element; An end face cam is connected to the rotary actuator and rotates with the rotary actuator about an axis. The end face cam has a plurality of positioning areas arranged in a circumferential direction. Each positioning area includes a stabilizing platform. The height of the stabilizing platform is one of at least three different heights. The at least three different heights are repeated in a predetermined cyclic sequence along the circumferential direction. The driven bracket is constrained to move only along the axis direction and is used to sequentially engage with the plurality of positioning areas during the rotation of the rotating operating member. The magnet is fixedly mounted on the driven bracket; A single linear Hall sensor is positioned within the magnetic field range of the magnet to detect changes in magnetic field strength generated by the magnet moving axially with the driven support. The processor, connected to the linear Hall sensor, is configured to: map the output signal of the linear Hall sensor to at least three stable states corresponding to the at least three different heights; detect the transitions between the stable states; and determine the rotation direction of the rotating actuator according to the order of the transitions.

2. The single-Hall bidirectional rotary input device according to claim 1, characterized in that, It also includes an elastic element that applies a preload force toward the end face cam to the driven bracket, so that one end of the driven bracket abuts against the end face of the end face cam.

3. The single-Hall bidirectional rotary input device according to claim 1, characterized in that, It also includes a PCB board, with the magnet and the single linear Hall sensor placed on opposite sides of the PCB board.

4. The single-Hall bidirectional rotary input device according to claim 1, characterized in that, The number of the multiple positioning areas is 3m, where m is an integer greater than or equal to 2; every three adjacent positioning areas constitute a coding cycle, and the three positioning areas in each coding cycle have a first axial height, a second axial height and a third axial height, respectively, and the first axial height, the second axial height and the third axial height increase or decrease along the circumferential direction.

5. A single Hall effect bidirectional rotary input device according to claim 4, characterized in that, m is 4.

6. The single-Hall bidirectional rotary input device according to claim 1, characterized in that, A transition surface inclined relative to the circumferential direction is provided between adjacent stable platforms.

7. A single Hall effect bidirectional rotary input device according to claim 3, characterized in that, It also includes a positioning plate, the driven bracket is slidably mounted on the positioning plate, the positioning plate is fixedly connected to the PCB board, and the bottom cross section of the driven bracket is polygonal.

8. A single Hall effect bidirectional rotary input device according to claim 7, characterized in that, It also includes a support housing, which is fixedly mounted on the positioning plate. The rotating operating component is disposed above the support housing, and the end face cam is disposed inside the support housing. The rotating operating component and the end face cam are connected by a connecting shaft, which is rotatably mounted on the top of the support housing and passes through the support housing.

9. A method for direction recognition using the single Hall bidirectional rotary input device according to any one of claims 1 to 8, characterized in that, include: The detection signal output by the single linear Hall sensor, which varies with the axial position of the magnet, is acquired. The detection signal is mapped to at least three discrete states corresponding to at least three axial positions based on at least two decision boundaries; The stability of the candidate discrete states obtained by mapping is verified to obtain the current stable state; Compare the current stable state with the previous stable state; When the current stable state migrates relative to the previous stable state along the predetermined cyclic sequence, it is determined to be the first rotation direction; when the current stable state migrates relative to the previous stable state along the reverse of the predetermined cyclic sequence, it is determined to be the second rotation direction.

10. The method according to claim 9, characterized in that, The stability verification includes: performing median calculation on multiple consecutive sampled values; obtaining candidate discrete states using decision boundaries with hysteresis regions; updating the current stable state when the candidate discrete states appear consecutively a predetermined number of times; not outputting step events for transition region samples that do not meet the stability verification conditions; and further includes: collecting statistical values ​​of detection signals at at least three axial positions during the calibration stroke, and setting at least two decision boundaries based on the boundaries between adjacent statistical values ​​to compensate for the tolerances of the magnet, the linear Hall sensor, the assembly spacing, and the cam structure.

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