Electric wheelchair speed limiting control method and device, electronic equipment and storage medium

Abstract

The application provides a power wheelchair speed limiting control method and device, electronic equipment and storage medium. The method calculates whether to stall through initial coordinate values generated by the inclination of a universal rocker. When it is determined that the power wheelchair stalls, the initial coordinate values generated by the inclination of the universal rocker are reduced to obtain reduced speed limiting coordinate values, and the speed limiting speed of the driving wheel of the power wheelchair is calculated accordingly, so as to avoid the power wheelchair from drifting or rolling over due to excessive speed. Since the calculation process of the speed limiting speed combines the coordinate values of the universal rocker and the straight line speed and the rotation line speed of the driving wheel, the calculated speed limiting speed can conform to the movement process of the power wheelchair, the turning radius of the power wheelchair can be gradually and gently adjusted, the driving experience is better, and the rolling over caused by excessive turning is effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of wheelchair speed limiting control technology, and in particular to a method, device, electronic device, and storage medium for speed limiting control of an electric wheelchair. Background Technology

[0002] When using a universal joystick to control an electric wheelchair controller, and thus control the independent movement of its two wheels, certain large coordinate values ​​output by the joystick to the controller can cause the electric wheelchair to turn too quickly, leading to dangers such as drifting or tipping over, or providing a poor driving experience for the driver. Some existing electric wheelchairs on the market also have speed limits, but the algorithms are simple and do not take into account the actual movement process. This results in irregular changes in the turning radius of the wheelchair when adjusting the speed limit parameters, leading to a worse driving experience and still posing a high degree of danger. Summary of the Invention

[0003] Therefore, it is necessary to provide a method, device, electronic device, and storage medium for controlling the speed limit of an electric wheelchair in response to the above-mentioned technical problems.

[0004] A method for controlling the speed limit of an electric wheelchair, comprising:

[0005] Obtain the tilt coordinate values ​​of the omnidirectional joystick on a plane, wherein the tilt coordinate values ​​include a first original coordinate value on a first coordinate axis and a second original coordinate value on a second coordinate axis in a planar coordinate system, wherein the first coordinate axis and the second coordinate axis are perpendicular to each other;

[0006] Detect whether the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter;

[0007] When the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, the first original coordinate value and the second original coordinate value are reduced according to the preset speed limit algorithm to obtain the first speed limit coordinate value and the second speed limit coordinate value.

[0008] Obtain the linear velocity of the drive wheel in the straight line and the linear velocity of its rotation;

[0009] Based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line velocity and the rotational velocity of the drive wheel, the motion speed of the drive wheel is calculated.

[0010] The drive wheel's movement is controlled based on the stated speed.

[0011] In one embodiment, after the step of detecting whether the product of the first original coordinate value and the second original coordinate value is greater than a preset speed limit parameter, the method further includes:

[0012] When the product of the first original coordinate value and the second original coordinate value is less than or equal to the preset speed limit parameter, the speed of the drive wheel is calculated based on the first original coordinate value, the second original coordinate value, the straight-line speed and the rotational speed of the drive wheel;

[0013] The drive wheel's movement is controlled based on the stated speed.

[0014] In one embodiment, the preset speed limiting algorithm is:

[0015]

[0016] Where x0 is the first original coordinate value, y0 is the second original coordinate value, L is the preset speed limit parameter, x1 is the first speed limit coordinate value, y1 is the second speed limit coordinate value, and k is the ratio of the second original coordinate value to the first original coordinate value.

[0017] In one embodiment, the step of calculating the speed of the drive wheel based on the first speed-limiting coordinate value, the second speed-limiting coordinate value, the straight-line velocity and the rotational velocity of the drive wheel includes:

[0018] Based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line speed and the rotational speed of the drive wheel, the first speed of the left drive wheel and the second speed of the right drive wheel are calculated according to the differential control calculation formula.

[0019] The step of controlling the movement of the drive wheel based on the motion speed includes:

[0020] The left drive wheel is controlled to move based on the first speed, and the right drive wheel is controlled to move based on the second speed.

[0021] In one embodiment, the differential control calculation formula is:

[0022]

[0023] Among them, speed max Spin is the linear velocity of the drive wheel in the straight line. max Let X be the linear velocity of the drive wheel rotating in place around the center points of the left and right drive wheels; let Y be the ratio of the first speed-limiting coordinate value to the radius of the output range of the omnidirectional rocker arm on the plane; let V be the ratio of the second speed-limiting coordinate value to the radius of the output range of the omnidirectional rocker arm on the plane; and let V be the linear velocity of the drive wheel rotating in place around the center points of the left and right drive wheels. L V is the first velocity of motion. R This is the second velocity.

[0024] An electric wheelchair speed limiting control device includes a universal rocker arm, a control module, and drive wheels;

[0025] The universal joystick is used to acquire control commands, determine tilt coordinate values ​​on the plane according to the control commands, and send the tilt coordinate values ​​to the control module. The tilt coordinate values ​​include a first original coordinate value on a first coordinate axis and a second original coordinate value on a second coordinate axis in the plane coordinate system, wherein the first coordinate axis and the second coordinate axis are perpendicular to each other.

[0026] The control module is used to detect whether the product of the first original coordinate value and the second original coordinate value is greater than a preset speed limit parameter; when the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, the first original coordinate value and the second original coordinate value are reduced according to the preset speed limit algorithm to obtain the first speed limit coordinate value and the second speed limit coordinate value; the linear velocity and rotational velocity of the drive wheel are obtained; based on the first speed limit coordinate value, the second speed limit coordinate value, the linear velocity and rotational velocity of the drive wheel, the motion speed of the drive wheel is calculated; and the motion of the drive wheel is controlled based on the motion speed.

[0027] In one embodiment, the control module includes a speed limit parameter storage unit, a stall detection unit, a coordinate transformation unit, and a coordinate speed transformation unit;

[0028] The speed limit parameter storage unit is used to store the preset speed limit parameters;

[0029] The stall detection unit is used to read the preset speed limit parameter from the speed limit parameter storage unit, detect whether the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, and when the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, a stall is determined, and the result of determining a stall is sent to the coordinate transformation unit.

[0030] The coordinate transformation unit is used to perform a reduction calculation on the first original coordinate value and the second original coordinate value according to a preset speed limiting algorithm when it receives a result that is determined to be a stall, to obtain the first speed limiting coordinate value and the second speed limiting coordinate value, and to send the first speed limiting coordinate value and the second speed limiting coordinate value to the coordinate speed transformation unit.

[0031] The coordinate velocity conversion unit is used to obtain the linear velocity and rotational velocity of the drive wheel; based on the first speed limit coordinate value, the second speed limit coordinate value, the linear velocity and rotational velocity of the drive wheel, the motion speed of the drive wheel is calculated; and the motion of the drive wheel is controlled based on the motion speed.

[0032] In one embodiment, the control module is further configured to calculate the speed of the drive wheel based on the first original coordinate value, the second original coordinate value, the straight-line speed and the rotational speed of the drive wheel when the product of the first original coordinate value and the second original coordinate value is less than or equal to the preset speed limit parameter; and control the movement of the drive wheel based on the speed of movement.

[0033] An electronic device includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the computer program to implement the steps of the electric wheelchair speed limiting control method described in any of the above embodiments.

[0034] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the electric wheelchair speed limiting control method described in any of the above embodiments.

[0035] The aforementioned electric wheelchair speed limiting control method, device, electronic equipment, and storage medium calculate whether a stall has occurred based on the initial coordinate values ​​generated by the tilting of the universal joystick. If a stall is detected, the initial coordinate values ​​generated by the tilting of the universal joystick are reduced to obtain reduced speed limiting coordinate values. Based on these reduced values, the speed limit of the electric wheelchair's drive wheels is calculated, thereby preventing the electric wheelchair from drifting or tipping over due to excessive speed. Because the speed limiting calculation process combines the coordinate values ​​of the universal joystick with the linear speeds of the drive wheels (both linear and rotational), the calculated speed limit conforms to the movement of the electric wheelchair. This allows for a gradual and smooth adjustment of the wheelchair's turning radius, resulting in a better driving experience and effectively preventing tipping over due to excessive turning. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating the speed limiting control method for an electric wheelchair in one embodiment;

[0037] Figure 2A This is a structural block diagram of an electric wheelchair speed limiting control device in one embodiment;

[0038] Figure 2B This is a structural block diagram of an electric wheelchair speed limiting control device in one embodiment;

[0039] Figure 3 This is a schematic diagram of the processing logic of the electric wheelchair speed limit control algorithm in one embodiment;

[0040] Figure 4 This is an image of the coordinates on the unit circle output by the omnidirectional joystick in one embodiment, processed by a speed limiting algorithm.

[0041] Figure 5 This is a diagram of the internal structure of an electronic device in one embodiment. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0043] Example 1

[0044] In this embodiment, as Figure 1 As shown, a speed limiting control method for an electric wheelchair is provided, which includes:

[0045] Step 110: Obtain the tilt coordinate values ​​of the universal joystick on the plane, wherein the tilt coordinate values ​​include a first original coordinate value on a first coordinate axis and a second original coordinate value on a second coordinate axis in the planar coordinate system, wherein the first coordinate axis and the second coordinate axis are perpendicular to each other.

[0046] In this embodiment, the omnidirectional joystick can rotate or tilt on a preset plane, and the maximum output range (range of motion) of the joystick on the plane is circular. Under the user's control, the joystick can tilt at any angle within its output range. This tilt angle can be converted into coordinate values ​​in a coordinate system on the plane. By controlling the tilt of the joystick, the electric wheelchair can be turned accordingly. In this embodiment, the coordinate values ​​of the joystick on a unit circle in the first quadrant of the input plane coordinate system are selected as the tilt coordinate values.

[0047] When the omnidirectional joystick tilts, a tilt signal is generated. The control module can obtain the tilt value of the omnidirectional joystick, which includes x on the X-axis and y on the Y-axis of the planar coordinate system. Therefore, the tilt value can be represented as (x, y). The first original coordinate value and the second original coordinate value are (x0, y0).

[0048] Step 120: Detect whether the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter.

[0049] In this embodiment, the preset speed limit parameter is L, which is pre-stored in the speed limit parameter storage unit and serves as the basis for stall judgment. Specifically, the stall judgment basis is...

[0050] x·y>L(1)

[0051] When x·y > L is true, it indicates stalling; when x·y > L is false, it indicates no stalling. It's worth noting that this preset speed limit parameter L can be modified. Therefore, by modifying the preset speed limit parameter L, the degree of speed limitation can be adjusted. In other words, the degree of speed limitation can be determined based on factors such as the electric wheelchair's load and tire wear, and the preset speed limit parameter L can be adjusted accordingly. This allows for speed control of electric wheelchairs under different conditions, adapting to the braking of different electric wheelchairs and making speed control more precise.

[0052] Step 130: When the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, the first original coordinate value and the second original coordinate value are reduced according to the preset speed limit algorithm to obtain the first speed limit coordinate value and the second speed limit coordinate value.

[0053] In this embodiment, when the product of the first and second original coordinate values ​​is greater than a preset speed limit parameter, it indicates that the electric wheelchair has stalled. Therefore, the first and second original coordinate values ​​are reduced according to the preset speed limit algorithm, resulting in the reduced coordinates (x0, y0) as (x1, y1), where the first speed limit coordinate is x1 and the second speed limit coordinate is y1. By reducing the coordinate values, the tilt amplitude and the speed of the electric wheelchair can be effectively reduced, thereby achieving a speed limit effect.

[0054] Step 140: Obtain the linear velocity of the drive wheel in the straight line and the linear velocity of its rotation.

[0055] In this embodiment, the electric wheelchair has two drive wheels. The linear velocity of the drive wheels when they are moving in a straight line is the linear velocity of moving in a straight line. The rotational linear velocity of the drive wheels refers to the linear velocity of the drive wheels rotating in place around the center point of the drive wheels on the left and right sides.

[0056] Step 150: Calculate the speed of the drive wheel based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line speed and the rotational speed of the drive wheel.

[0057] In this embodiment, the motion speed of the two drive wheels of the electric wheelchair can be calculated using the first speed limit coordinate value, the second speed limit coordinate value, the straight-line velocity of the drive wheel, and the rotational velocity. This motion speed refers to the rotational speed of the drive wheel.

[0058] Step 160: Control the movement of the drive wheel based on the movement speed.

[0059] In the above embodiments, the initial coordinate values ​​generated by the tilt of the universal joystick are used to calculate whether a stall has occurred. If a stall is detected, the initial coordinate values ​​generated by the tilt of the universal joystick are reduced to obtain reduced speed-limiting coordinate values. Based on this, the speed limit of the electric wheelchair's drive wheels is calculated, thereby preventing the electric wheelchair from drifting or tipping over due to excessive speed. Because the speed-limiting calculation process combines the coordinate values ​​of the universal joystick with the linear velocity and rotational velocity of the drive wheels, the calculated speed limit is consistent with the movement process of the electric wheelchair. This allows the turning radius of the electric wheelchair to be adjusted gradually and smoothly, resulting in a better driving experience and effectively preventing tipping over due to excessive turning.

[0060] In one embodiment, after the step of detecting whether the product of the first original coordinate value and the second original coordinate value is greater than a preset speed limit parameter, the method further includes:

[0061] When the product of the first original coordinate value and the second original coordinate value is less than or equal to the preset speed limit parameter, the speed of the drive wheel is calculated based on the first original coordinate value, the second original coordinate value, the straight-line speed and the rotational speed of the drive wheel; the movement of the drive wheel is controlled based on the speed of the drive wheel.

[0062] In this embodiment, when the product of the first and second original coordinate values ​​is less than the preset speed limit parameter, i.e., x0*y0≤L, it means that the electric wheelchair has not stalled. Therefore, there is no need to reduce the first and second original coordinate values ​​during calculation. The speed of the drive wheel can be calculated based on the first and second original coordinate values, the linear velocity of the drive wheel, and the linear velocity of its rotation. Since the electric wheelchair does not stall, the speed of the drive wheel is not limited, thereby improving the efficiency of the electric wheelchair's movement.

[0063] In one embodiment, the preset speed limiting algorithm is:

[0064]

[0065] Where x0 is the first original coordinate value, y0 is the second original coordinate value, L is the preset speed limit parameter, x1 is the first speed limit coordinate value, y1 is the second speed limit coordinate value, and k is the ratio of the second original coordinate value to the first original coordinate value.

[0066] In this embodiment, the degree of speed limit can be controlled by adjusting the value of the preset speed limit parameter L. x1 and y1 are the adjusted coordinate values ​​obtained by shrinking the original coordinate values ​​(x0, y0) after being processed by the preset speed limit algorithm. They are the first speed limit coordinate values ​​on the X-axis and the second speed limit coordinate values ​​on the Y-axis.

[0067] The coordinate value reduction calculation method used in this application can ensure that during the adjustment of the preset speed limit parameter L, the overall motion radius R of the wheelchair and k in the calculation formula (2) are always a unique and continuously differentiable function. This makes it possible to have three advantages in terms of the overall driving experience: First, when the universal rocker angle remains unchanged but the offset changes, the overall motion radius of the vehicle remains unchanged, which is consistent with driving intuition; second, the change of the overall turning radius R when adjusting the angle is very smooth; and third, customers with different speed limit requirements have the same turning radius control experience.

[0068] In one embodiment, the step of calculating the motion speed of the drive wheel based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line velocity and the rotational velocity of the drive wheel includes: calculating the first motion speed of the left drive wheel and the second motion speed of the right drive wheel according to the differential control calculation formula based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line velocity and the rotational velocity of the drive wheel; in this embodiment, the step of controlling the motion of the drive wheel based on the motion speed includes: controlling the motion of the left drive wheel based on the first motion speed and controlling the motion of the right drive wheel based on the second motion speed.

[0069] In this embodiment, the electric wheelchair has two drive wheels: a left drive wheel on the left and a right drive wheel on the right. Using a differential control formula, a first speed for driving the left drive wheel can be calculated based on a first speed limit coordinate value, a second speed limit coordinate value, and the linear velocity and rotational velocity of the left drive wheel. Similarly, a second speed for driving the right drive wheel can be calculated using the same formula. Thus, the first speed of the left drive wheel and the second speed of the right drive wheel are related to their respective linear velocities and rotational velocities, ensuring that these speeds are adapted to the current linear velocities of the drive wheels, resulting in smoother turning of the electric wheelchair.

[0070] In one embodiment, the differential control calculation formula is:

[0071]

[0072] Among them, speed max Spin is the linear velocity of the drive wheel in the straight line. max Let X be the linear velocity of the drive wheel rotating in place around the center points of the left and right drive wheels; let Y be the ratio of the first speed-limiting coordinate value to the radius of the output range of the omnidirectional rocker arm on the plane; let V be the ratio of the second speed-limiting coordinate value to the radius of the output range of the omnidirectional rocker arm on the plane; and let V be the linear velocity of the drive wheel rotating in place around the center points of the left and right drive wheels. LV is the first velocity of motion. R This is the second velocity.

[0073] In this embodiment, the coordinates obtained after being reduced by the preset speed limiting algorithm are new (x1, y1). Correspondingly, the ratios of x1 and y1 to the radius of the output range of the omnidirectional joystick are X and Y, respectively. The linear speeds of the left and right drive wheels are both denoted as speed. max The linear velocity of a tire rotating in place around the center point of the left and right drive wheels is denoted as spin. max Based on the differential control principle, the speeds of the left and right drive wheels can be calculated as V. L and V R .

[0074] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order in which these steps are executed, and they can be performed in other orders. Furthermore, Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0075] Example 2

[0076] In this embodiment, as Figure 2A As shown, an electric wheelchair speed limiting control device is provided, including: a universal rocker arm 100, a control module 200, and a drive wheel 300;

[0077] The universal joystick 100 is used to acquire control commands, determine tilt coordinate values ​​on the plane according to the control commands, and send the tilt coordinate values ​​to the control module 200. The tilt coordinate values ​​include a first original coordinate value on a first coordinate axis and a second original coordinate value on a second coordinate axis in the plane coordinate system, wherein the first coordinate axis and the second coordinate axis are perpendicular to each other.

[0078] The control module 200 is used to detect whether the product of the first original coordinate value and the second original coordinate value is greater than a preset speed limit parameter; when the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, the first original coordinate value and the second original coordinate value are reduced according to the preset speed limit algorithm to obtain the first speed limit coordinate value and the second speed limit coordinate value; the straight-line speed and rotational speed of the drive wheel 300 are obtained; based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line speed and rotational speed of the drive wheel 300, the movement speed of the drive wheel 300 is calculated; and the movement of the drive wheel 300 is controlled based on the movement speed.

[0079] In one embodiment, the control module 200 includes a speed limit parameter storage unit 210, a stall detection unit 220, a coordinate transformation unit 230, and a coordinate speed transformation unit 240.

[0080] The speed limit parameter storage unit 210 is used to store the preset speed limit parameters;

[0081] The stall detection unit 220 is used to read the preset speed limit parameter from the speed limit parameter storage unit 210, detect whether the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, and when the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, a stall is determined, and the result of determining a stall is sent to the coordinate transformation unit 230.

[0082] When the coordinate transformation unit 230 receives a result determined to be a stall, it performs a reduction calculation on the first original coordinate value and the second original coordinate value according to a preset speed limiting algorithm to obtain the first speed limiting coordinate value and the second speed limiting coordinate value, and sends the first speed limiting coordinate value and the second speed limiting coordinate value to the coordinate speed transformation unit 240.

[0083] The coordinate velocity conversion unit 240 is used to obtain the linear velocity and rotational velocity of the drive wheel 300; based on the first speed limit coordinate value, the second speed limit coordinate value, the linear velocity and rotational velocity of the drive wheel 300, the motion speed of the drive wheel 300 is calculated; and the motion of the drive wheel 300 is controlled based on the motion speed.

[0084] In one embodiment, the control module 200 is further configured to calculate the speed of the drive wheel 300 based on the first original coordinate value, the second original coordinate value, the straight-line speed and the rotational speed of the drive wheel 300 when the product of the first original coordinate value and the second original coordinate value is less than or equal to the preset speed limit parameter; and control the drive wheel 300 to move based on the speed of movement.

[0085] In one embodiment, the preset speed limiting algorithm is:

[0086]

[0087] Where x0 is the first original coordinate value, y0 is the second original coordinate value, L is the preset speed limit parameter, x1 is the first speed limit coordinate value, y1 is the second speed limit coordinate value, and k is the ratio of the second original coordinate value to the first original coordinate value.

[0088] In one embodiment, the control module 200 is further configured to calculate, based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line speed and the rotational speed of the drive wheel 300, and according to the differential control calculation formula, the first speed of the left drive wheel 310 and the second speed of the right drive wheel 320; control the left drive wheel 310 to move based on the first speed and control the right drive wheel 320 to move based on the second speed.

[0089] In one embodiment, the differential control calculation formula is:

[0090]

[0091] Among them, speed max For the straight-line speed of the drive wheel 300, spin max Let X be the linear velocity of the drive wheel 300 rotating in place around the center points of the left drive wheel 310 and the right drive wheel 320; let X be the ratio of the first speed-limiting coordinate value to the radius of the output range of the omnidirectional rocker arm 100 on the plane; let Y be the ratio of the second speed-limiting coordinate value to the radius of the output range of the omnidirectional rocker arm 100 on the plane; and let V be the linear velocity of the drive wheel 300 rotating in place around the center points of the left drive wheel 310 and the right drive wheel 320 on the plane. L V is the first velocity of motion. R This is the second velocity.

[0092] Example 3

[0093] In this embodiment, as Figure 2B As shown, the electric wheelchair speed limiting control device includes a universal rocker arm 100, a microcontroller 200, and a drive wheel 300. In this embodiment, the shape formed by the maximum range of motion of the universal rocker arm on the plane is a circle. The coordinates of the first quadrant of the coordinate system on the plane of the universal rocker arm are taken as the initial coordinate values, and the coordinates of the other quadrants are handled similarly.

[0094] The functions of each component are as follows:

[0095] The omnidirectional joystick 100 is controlled by the driver. It converts the joystick's tilt into a coordinate value (x, y) within a plane circle and outputs it to the microcontroller for processing.

[0096] The microcontroller 200 includes a speed limit parameter storage unit 210, a stall detector 220, a coordinate converter 230, and a coordinate-velocity converter 240.

[0097] The speed limit parameter storage unit 210 stores a preset speed limit parameter L. By modifying the preset speed limit parameter L, the degree of speed restriction imposed by the preset speed limit algorithm can be adjusted.

[0098] The stall detection device 220 reads the preset speed limit parameter L, receives coordinate values ​​from the microcontroller 200, calculates and judges the coordinate values, and transmits the coordinate values ​​and the calculation results to the coordinate converter 230.

[0099] The coordinate converter 230 receives the coordinates (x, y) and the judgment result from the stall detection device. If the device determines that there is a stall risk, it applies a speed limiting algorithm to the coordinate values; otherwise, it does not process them. The coordinate values ​​are then transmitted to the coordinate-velocity converter 240.

[0100] The coordinate-velocity converter 240 receives the coordinate values ​​processed by the coordinate converter 230, substitutes them into the differential control algorithm for calculation, obtains the theoretical speed (driving speed) of the drive wheel after speed limit, and outputs it to the drive wheel.

[0101] The drive wheels 300, including a left drive wheel 310 and a right drive wheel 320, operate completely independently without a mechanical differential. The motor is controlled by receiving drive speed from a coordinate-speed converter 240.

[0102] like Figure 3 The diagram illustrates the calculation logic of speed limit control. First, the initial tilted coordinates (x, y) are calculated to check if x*y is greater than the preset speed limit parameter L. If x*y is greater than L, the initial coordinates (x, y) are reduced and recalculated. If x*y is less than or equal to L, the initial coordinates (x, y) remain unchanged. Then, the processed coordinates are used to calculate and convert the speeds of the left and right drive wheels.

[0103] like Figure 4 As shown, the coordinate values ​​of the omnidirectional joystick output to the drive wheel are displayed on the coordinate system through the speed limiting control algorithm. The dashed line represents the initial coordinate value, and the solid line represents the coordinate value output after the speed limiting algorithm. Figure 4 In this diagram, the input coordinates of the selected omnidirectional joystick are located in the first quadrant of the planar coordinate system. The maximum range of motion of the omnidirectional joystick is represented by coordinates on a unit circle, which are shown as points in the diagram. The output is the coordinates of these coordinates after processing, which are then sent to the coordinate-velocity converter 240, and their positions are represented by lines.

[0104] The specific calculation of the stall detector 220 is as follows: The preset speed limit parameter in the speed limit parameter storage unit 210 is L, and the stall judgment basis of 220 is x·y>L(1). If equation (1) holds, it is considered that a stall will occur; otherwise, it will not.

[0105] The detailed operation process of coordinate converter 230 is as follows: If the stall detector sends a stall signal, the following reduction process is performed: Let the original coordinates be (x0, y0) and the reduced coordinates be (x1, y1), then:

[0106]

[0107] The degree of speed limit can be controlled by adjusting the preset speed limit parameter L. In this embodiment, the calculation method of coordinate reduction has a very important property: that is, it can ensure that during the process of adjusting the preset speed limit parameter L, the overall motion radius R of the wheelchair and k in (2) are always a unique and continuously differentiable function. From the perspective of the overall driving experience, there are three advantages: First, when the angle of the universal rocker arm 100 remains unchanged but the offset changes, the overall motion radius of the vehicle remains unchanged, which is consistent with driving intuition; second, the change of the overall turning radius R when adjusting the angle is very smooth; and third, customers with different speed limit requirements have the same turning radius control experience.

[0108] The detailed calculation process of the coordinate-velocity converter 240 is as follows: Let the coordinates processed by the coordinate converter 230 be the new (x, y). The ratios of the corresponding x and y values ​​to the radius of the output range circle of the omnidirectional rocker arm 100 are X and Y, respectively. The linear velocity of the tires during straight-line travel and rotation around the center point of the two drive wheels is denoted as speed. max and spin max The speeds of the left and right drive wheels are V and V, respectively. L and V R According to the differential control principle, we can have:

[0109]

[0110] The calculation result of the above formula is the final result of the speed limit control algorithm. The calculation result is sent to the left drive wheel 310 and the right drive wheel 320 respectively, thus completing the entire control process.

[0111] Specific limitations regarding the electric wheelchair speed limiting control device can be found in the above description of the electric wheelchair speed limiting control method, and will not be repeated here. Each unit in the aforementioned electric wheelchair speed limiting control device can be implemented entirely or partially through software, hardware, or a combination thereof. These units can be embedded in or independent of the processor in the electronic device in hardware form, or stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of each unit.

[0112] Example 4

[0113] In this embodiment, an electronic device is provided. Its internal structure diagram can be shown as follows: Figure 5 As shown, the electronic device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface is used to communicate with other electronic devices that have application software deployed. When the computer program is executed by the processor, it implements a speed-limiting control method for an electric wheelchair. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the device's casing, or an external keyboard, touchpad, or mouse.

[0114] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the electronic device to which the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0115] In one embodiment, an electronic device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the electric wheelchair speed limiting control method described in any of the above embodiments.

[0116] Example 5

[0117] In this embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps of the electric wheelchair speed limiting control method described in any of the above embodiments.

[0118] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A speed limiting control method for an electric wheelchair, characterized in that, Including the following steps: Obtain the tilt coordinate values ​​of the omnidirectional joystick on a plane, wherein the tilt coordinate values ​​include a first original coordinate value on a first coordinate axis and a second original coordinate value on a second coordinate axis in a planar coordinate system, wherein the first coordinate axis and the second coordinate axis are perpendicular to each other; Detect whether the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter; When the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, the first original coordinate value and the second original coordinate value are reduced according to the preset speed limit algorithm to obtain the first speed limit coordinate value and the second speed limit coordinate value. Obtain the linear velocity of the drive wheel in the straight line and the linear velocity of its rotation; Based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line velocity and the rotational velocity of the drive wheel, the motion speed of the drive wheel is calculated. The drive wheel's movement is controlled based on the stated speed.

2. The method according to claim 1, characterized in that, After the step of detecting whether the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, the method further includes: When the product of the first original coordinate value and the second original coordinate value is less than or equal to the preset speed limit parameter, the speed of the drive wheel is calculated based on the first original coordinate value, the second original coordinate value, the straight-line speed and the rotational speed of the drive wheel; The drive wheel's movement is controlled based on the stated speed.

3. The method according to claim 1, characterized in that, The preset speed limit algorithm is as follows: Where x0 is the first original coordinate value, y0 is the second original coordinate value, L is the preset speed limit parameter, x1 is the first speed limit coordinate value, y1 is the second speed limit coordinate value, and k is the ratio of the second original coordinate value to the first original coordinate value.

4. The method according to claim 1, characterized in that, The step of calculating the speed of the drive wheel based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line velocity and the rotational velocity of the drive wheel includes: Based on the first speed limit coordinate value, the second speed limit coordinate value, the straight-line speed and the rotational speed of the drive wheel, the first speed of the left drive wheel and the second speed of the right drive wheel are calculated according to the differential control calculation formula. The step of controlling the movement of the drive wheel based on the motion speed includes: The left drive wheel is controlled to move based on the first speed, and the right drive wheel is controlled to move based on the second speed.

5. The method according to claim 4, characterized in that, The differential control calculation formula is: Among them, speed max Spin is the linear velocity of the drive wheel in the straight line. max Let X be the linear velocity of the drive wheel rotating in place around the center points of the left and right drive wheels; let Y be the ratio of the first speed-limiting coordinate value to the radius of the output range of the omnidirectional rocker arm on the plane; let V be the ratio of the second speed-limiting coordinate value to the radius of the output range of the omnidirectional rocker arm on the plane; and let V be the linear velocity of the drive wheel rotating in place around the center points of the left and right drive wheels. L V is the first velocity of motion. R This is the second velocity.

6. A speed limiting control device for an electric wheelchair, characterized in that, Includes a universal joystick, control module, and drive wheels; The universal joystick is used to acquire control commands, determine tilt coordinate values ​​on the plane according to the control commands, and send the tilt coordinate values ​​to the control module. The tilt coordinate values ​​include a first original coordinate value on a first coordinate axis and a second original coordinate value on a second coordinate axis in the plane coordinate system, wherein the first coordinate axis and the second coordinate axis are perpendicular to each other. The control module is used to detect whether the product of the first original coordinate value and the second original coordinate value is greater than a preset speed limit parameter; when the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, the first original coordinate value and the second original coordinate value are reduced according to the preset speed limit algorithm to obtain the first speed limit coordinate value and the second speed limit coordinate value; the linear velocity and rotational velocity of the drive wheel are obtained; based on the first speed limit coordinate value, the second speed limit coordinate value, the linear velocity and rotational velocity of the drive wheel, the motion speed of the drive wheel is calculated; and the motion of the drive wheel is controlled based on the motion speed.

7. The apparatus according to claim 6, characterized in that, The control module includes a speed limit parameter storage unit, a stall detection unit, a coordinate transformation unit, and a coordinate speed transformation unit. The speed limit parameter storage unit is used to store the preset speed limit parameters; The stall detection unit is used to read the preset speed limit parameter from the speed limit parameter storage unit, detect whether the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, and when the product of the first original coordinate value and the second original coordinate value is greater than the preset speed limit parameter, a stall is determined, and the result of determining a stall is sent to the coordinate transformation unit. The coordinate transformation unit is used to perform a reduction calculation on the first original coordinate value and the second original coordinate value according to a preset speed limiting algorithm when it receives a result that is determined to be a stall, to obtain the first speed limiting coordinate value and the second speed limiting coordinate value, and to send the first speed limiting coordinate value and the second speed limiting coordinate value to the coordinate speed transformation unit. The coordinate velocity conversion unit is used to obtain the linear velocity and rotational velocity of the drive wheel; based on the first speed limit coordinate value, the second speed limit coordinate value, the linear velocity and rotational velocity of the drive wheel, the motion speed of the drive wheel is calculated; and the motion of the drive wheel is controlled based on the motion speed.

8. The apparatus according to claim 6, characterized in that, The control module is also used to calculate the speed of the drive wheel based on the first original coordinate value, the second original coordinate value, the straight-line speed and the rotational speed of the drive wheel when the product of the first original coordinate value and the second original coordinate value is less than or equal to the preset speed limit parameter; The drive wheel's movement is controlled based on the stated speed.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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