Power-assisted steering control method and system for self-walking mower

Abstract

The invention discloses a power-assisted steering control system and a power-assisted steering control method for a self-driven walking type mower. The power-assisted steering control system comprises at least two driving wheels and at least two motors, and the motors are connected with and drive the driving wheels respectively; the self-walking type lawn mower further comprises at least one motion sensor which is arranged on the self-walking type lawn mower and used for measuring motion trend parameters of the self-walking type lawn mower. The control module is connected with the motion sensor and the motor at the same time; the control module is used for cooperatively controlling the rotating speed of motors connected with driving wheels on the two sides of the self-walking type mower when the self-walking type mower has the steering trend and controlling the self-walking type mower to steer according to advancing motion parameters, and the advancing motion parameters are smaller than motion trend parameters. In the steering process, operation is easier and more convenient, man-machine interaction experience is better, and the overall mowing effect is better.

Description

Technical Field

[0001] The invention relates to a power control system of a lawn mower, and in particular to a power steering control method and system for a self-propelled lawn mower. Background Art

[0002] When an existing lawn mower encounters an obstacle or reaches the end of the lawn, a person needs to turn the handle to turn the machine, which is inconvenient to operate. Especially for a self-propelled lawn mower, its two rear wheels drive the machine forward at the same speed at the same time. During the self-propelled process, due to the drive of the rear wheels, it is difficult for manpower to directly turn the machine. Usually, when a self-propelled lawn mower needs to turn, the operator needs to first turn off the self-propelled function, that is, stop the drive of the rear wheels of the lawn mower, and then turn the machine to turn. Such a design makes the existing self-propelled lawn mower cumbersome to operate when turning, and the operation continuity is poor.

[0003] In particular, since the existing self-propelled lawn mowers need to turn off the rear wheel drive before turning, users who are not familiar with the operation of the lawn mower may easily trigger the main switch of the lawn mower by mistake during the turning operation, thereby causing the lawn mower to shut down by mistake. The actual user experience is not ideal.

[0004] In this regard, Honda has proposed a solution to automatically reduce the drive speed during the steering process of the lawn mower in the US9616893B2 application. However, this solution only adjusts the ground speed of the self-propelled machine during the steering process through the response of the control unit to the sensor. Its purpose is only to simplify the operation of the rear wheel drive switch during the steering process to avoid accidentally touching the switch. This solution is still lacking in intelligence. In particular, after reducing the ground speed, it is still necessary to manually push the machine to adjust the direction of travel of the machine. Due to the large friction coefficient of the grass and the large weight of the machine, even when the travel drive of the machine has been turned off, it is still difficult to achieve precise control by manual adjustment of the direction of travel of the machine. It is difficult to ensure that the direction of travel of the lawn mower after turning is flush with the original direction, and it is likely to require repeated manual adjustments. In the process of repeated manual adjustments, it is easy for the mowing mechanism to repeatedly operate back and forth at the same position, affecting the mowing effect at the turn.

[0005] At the same time, during the operation of the lawn mower, due to the uneven road surface, the lawn mower may turn due to the terrain. The above Honda application also did not solve the problem of interference with the lawn mower motion sensor due to uneven ground or misoperation, and thus could not solve the problem of erroneous control of the machine drive. When using a lawn mower, even if the operator tries his best to maintain balance, sometimes an arc will be pushed out, resulting in low mowing efficiency and affecting the beauty of the lawn.

[0006] The above problems are difficult to be overcome by the prior art. Therefore, there is an urgent need for a self-propelled lawn mower that can achieve steering during self-propelled operation and automatically maintain a stable moving direction of the machine body. Summary of the invention

[0007] To address the deficiencies of the prior art, the present invention aims to provide a self-propelled lawn mower that can achieve steering and maintain a stable moving direction of the machine body during self-propelled travel through simple operations, a power steering control method for the lawn mower, and a corresponding system.

[0008] In order to achieve the above object, the present invention adopts the following technical solution: The present invention first provides a power steering control method for a self-propelled lawn mower, the steps comprising: The first step is to synchronously drive the driving wheels on both sides of the self-propelled lawn mower and measure the motion trend parameters of the self-propelled lawn mower; the second step is to control the self-propelled lawn mower to turn with the travel motion parameter if the self-propelled lawn mower has a turning trend, and the travel motion parameter is less than the motion trend parameter; if the motion trend parameter does not have a turning trend, maintain or return to the first step; the third step is to repeat the first step to the second step until the drive of the self-propelled lawn mower is turned off.

[0009] Optionally, the motion trend parameter includes the actual angular acceleration α1 of the self-propelled lawn mower. In the second step, if the self-propelled lawn mower has a turning trend, the step of controlling the self-propelled lawn mower to turn with the traveling motion parameter includes: The traveling motion parameter is a traveling angular acceleration α2, and the self-propelled lawn mower is driven to travel at the traveling angular acceleration α2, and the traveling angular acceleration α2 is smaller than the actual angular acceleration α1.

[0010] Optionally, the motion trend parameter includes the actual angular velocity ω1 of the self-propelled lawn mower; in the second step, if the self-propelled lawn mower has a turning tendency, the step of controlling the self-propelled lawn mower to turn with the travel motion parameter includes: the travel motion parameter is the travel angular velocity ω2, driving the self-propelled lawn mower to travel at the travel angular velocity ω2, and the travel angular velocity ω2 is less than the actual angular velocity ω1.

[0011] Optionally, in the second step, the ratio of the rotational speeds of the driving wheels on both sides of the self-propelled lawn mower is determined according to the following steps: Step A1, measuring the actual angular velocity ω1 and the actual velocity v1 of the self-propelled lawn mower when it is moving, calculating the rotation radius r= v1 / ω1 of the self-propelled lawn mower when it is moving, and determining the rotation center O of the self-propelled lawn mower when it is moving; Step A2, calculating the ratio k of the distances from the driving wheels on both sides of the self-propelled lawn mower to the rotation center O; Step A3, the ratio of the speeds of the driving wheels on both sides of the self-propelled lawn mower is not greater than the ratio k of the distances from the driving wheels on both sides of the self-propelled lawn mower to the rotation center O.

[0012] Optionally, the ratio of the rotational speeds of the driving wheels on both sides of the self-propelled lawn mower changes with the magnitude of the traveling motion parameter.

[0013] Optionally, the self-propelled lawn mower includes a preset value. When the motion trend parameter is greater than the preset value, it is determined that the self-propelled lawn mower has a turning trend. When the motion trend parameter is less than the preset value, the self-propelled lawn mower is controlled to go straight. Optionally, the motion trend parameter also includes a first acceleration a1 of the self-propelled lawn mower in the direction of travel; the preset value corresponding to the actual acceleration a1 is the acceleration preset value a0; in the second step, the step of cooperatively controlling the rotation speed of the driving wheels on both sides of the self-propelled lawn mower and driving the self-propelled lawn mower to follow the motion trend parameter also includes: synchronously driving the driving wheels on both sides of the self-propelled lawn mower with a second acceleration a2, wherein the second acceleration a2 is less than the first acceleration a1, and the second acceleration a2 and the first acceleration a1 have a functional relationship. Optionally, the motion trend parameter also includes a first acceleration a1 of the self-propelled lawn mower in the direction of travel; the preset value corresponding to the actual acceleration a1 is the acceleration preset value a0; In the second step, the step of cooperatively controlling the rotation speed of the driving wheels on both sides of the self-propelled lawn mower to drive the moving state of the self-propelled lawn mower to follow the motion trend parameter also includes: synchronously driving the driving wheels on both sides of the self-propelled lawn mower with a second acceleration a2, wherein the second acceleration a2 is less than the first acceleration a1, and the second acceleration a2 is a constant.

[0014] The present invention also provides a power steering control system for a self-propelled lawn mower, comprising: at least two driving wheels respectively arranged on both sides of the self-propelled lawn mower, at least two motors, the motors are respectively connected to and drive the driving wheels on one side of the self-propelled lawn mower; also comprising: at least one motion sensor, the motion sensor is arranged on the self-propelled lawn mower, and is used to measure the motion trend parameters of the self-propelled lawn mower; a control module, the control module is simultaneously connected to the motion sensor and the motor; the control module is used to coordinately control the rotation speed of the motors connected to the driving wheels on both sides of the self-propelled lawn mower when the self-propelled lawn mower has a turning trend, and control the self-propelled lawn mower to turn according to the travel motion parameters, and the travel motion parameters are less than the motion trend parameters.

[0015] Optionally, a bidirectional overrunning clutch is further connected between the motor and the drive wheel connected thereto.

[0016] Optionally, the motion sensor includes one or a combination of an accelerometer, a gyroscope, a gravity sensor, a linear accelerometer or a rotation vector sensor.

[0017] Optionally, the self-propelled lawn mower includes a preset value, and when the motion trend parameter is greater than the preset value, it is determined that the self-propelled lawn mower has a turning trend, and when the motion trend parameter is less than the preset value, the self-propelled lawn mower is controlled to move straight.

[0018] The present invention also provides a self-propelled lawn mower, comprising: a body, support wheels, wherein the support wheels are arranged under the body for supporting the body; a mowing mechanism, wherein the mowing mechanism is arranged under the body for mowing; a control device, wherein the control device is used to control the operation of the self-propelled lawn mower; and also includes the power steering control system; wherein the motion sensor is arranged between the driving wheels on both sides of the self-propelled lawn mower; a control module in the power steering control system is connected to the control device, and the control device includes an interface for setting the preset value in the control module. Beneficial Effects

[0019] First, the present invention automatically responds to the change of motion state caused by manual adjustment during the travel of the lawn mower. Specifically, when the motion trend (at least including the actual angular acceleration α1 and the actual acceleration a1) of the self-propelled lawn mower is detected by the motion sensor due to the change of the motion trend (at least including the actual angular acceleration α1 and the actual acceleration a1) caused by the manual adjustment of the travel direction or speed of the lawn mower, the corresponding side or both motors are driven to accelerate or decelerate accordingly, thereby adjusting the angular velocity or acceleration (i.e., the second angular velocity ω2 or the second acceleration a2) of the overall autonomous travel of the lawn mower, so that the angular velocity or acceleration of its autonomous travel tends to the angular velocity or acceleration corresponding to the manual adjustment. When the lawn mower reaches the required speed or angle, the artificially applied adjustment amount gradually decreases to 0. At this time, the travel state of the lawn mower driven by itself follows the motion trend parameter, and the adjustment amount is gradually reduced, and the synchronous drive of the motors on both sides in the first step is gradually restored, so that the lawn mower automatically resumes straight and uniform travel. Therefore, the present invention can ensure that the lawn mower actively follows the manual adjustment in the travel direction to achieve steering or speed adjustment, without shutting down or reducing the drive of the lawn mower during the steering process, so as to achieve autonomous steering. The lawn mower of the present invention is easier to operate and has a better human-machine interaction experience during the turning process. In particular, when turning, the lawn mower of the present invention can respond to the movement trend of the lawn mower adjusted manually, drive the driving wheels on both sides to produce a speed difference and autonomously drive to achieve turning, without the need for manual repeated pushing and pulling of the machine to adjust the direction, and the mowing mechanism in the lawn mower of the present invention will not repeatedly operate back and forth at the same position, so the overall mowing effect is also better.

[0020] Furthermore, the present invention determines the movement trend of the self-propelled lawn mower, including the actual angular acceleration α1 and the actual acceleration a1, and also determines whether the movement state is adjusted according to the angular acceleration preset value α0 and the acceleration preset value a0. When the preset value is not reached, it is determined that the lawn mower has no change in the direction or speed of travel. In this way, interference with the data collected by the lawn mower motion sensor due to uneven ground can be avoided, and misoperation or misjudgment of the lawn mower's movement state can be avoided. The lawn mower using the technology of the present invention can ensure a stable and straight travel direction even when encountering a bumpy route by presetting and correcting the angular acceleration preset value α0 and the acceleration preset value a0, and the mowing effect is more beautiful.

[0021] Furthermore, the present invention also connects a two-way overrunning clutch between the motor and the drive wheel connected thereto. Since the driving shaft of the two-way overrunning clutch is connected to the motor, and the driven shaft is connected to the drive wheel. Therefore, during normal travel, the motor is connected to the driving shaft to rotate and drive the driven shaft, providing two-way drive for the drive wheel; when adjusting the travel of the lawn mower, when the speed of the driving shaft connected to the motor is adjusted and stopped, the driven shaft can be driven by the drive wheel to freely rotate in both directions, and smoothly change speed; when the driving shaft rotates, the speed generated by artificially pushing the lawn mower can drive the driven shaft through the drive wheel, and achieve overtaking in the same direction relative to the driving shaft. Therefore, when the motor speed changes, it can avoid excessive torque on the motor shaft due to the delay in the speed follow-up of the drive wheel, so that the lawn mower travels more smoothly, and the drive wheel changes speed smoothly during steering or speed adjustment, so that the lawn mower body travels more stably, thereby further improving the mowing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a three-dimensional structural schematic diagram of the self-propelled lawn mower of the present invention.

[0023] Figure 2 The invention is a power steering control system for a self-propelled lawn mower.

[0024] Figure 3 The invention relates to a power steering control method.

[0025] Figure 4 The invention discloses a power steering control method using angular acceleration as a parameter.

[0026] Figure 5 The invention discloses a power steering control method using angular velocity as a parameter.

[0027] Figure 6 The invention discloses a power steering control method using acceleration as a parameter.

[0028] Figure 7 It is another power steering control method of the present invention. Implementation

[0029] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Figure 1 It is a three-dimensional structural schematic diagram of the self-propelled lawn mower of the present invention. Figure 3It is a power steering control method of the present invention. The present invention proposes a power steering control system for a self-propelled lawn mower to implement the above-mentioned power steering control method, including at least two driving wheels respectively arranged on both sides of the self-propelled lawn mower, at least two motors 20, the motors 20 are respectively connected to and drive the driving wheels 10 on one side of the self-propelled lawn mower, and also includes: at least one motion sensor 30, the motion sensor 30 is arranged on the self-propelled lawn mower, and is used to measure the motion trend parameters of the self-propelled lawn mower; specifically, the motion trend parameters refer to the motion trend of the self-propelled lawn mower generated by the user's action on the self-propelled lawn mower, and are used to reflect the user's walking control of the self-propelled lawn mower.

[0031] A control module 50, wherein the control module 50 is connected to the motion sensor 30 and the motor 20 at the same time; the control module is used to coordinately control the rotation speed of the motors connected to the driving wheels on both sides of the self-propelled lawn mower after the motion trend parameters are measured by the motion sensor, so as to drive the self-propelled lawn mower to follow the motion trend parameters.

[0032] Wherein, the parameter value for driving the self-propelled lawn mower to move forward is not greater than the value of the motion trend parameter.

[0033] In particular, in one embodiment, when the motion trend parameter detected by the motion sensor is greater than a preset value, the control module controls the automatic walking lawn mower to follow the motion trend parameter and rotate; when the motion trend parameter is less than the preset value, the control module controls the automatic walking lawn mower to move straight.

[0034] In the above system, a speed change device 40 may be further provided between the motor and the drive wheel connected to the motor to match the motor speed with the drive wheel speed. Optionally, the speed change device is implemented as a transmission. The self-propelled lawn mower further includes a storage device, such as various storage devices, which is connected to the control module and is used to store algorithms and related data for controlling the operation of the self-propelled lawn mower.

[0035] The motion sensor includes one or a combination of an accelerometer, a gyroscope, a gravity sensor, a linear accelerometer or a rotation vector sensor. If the motion sensor detects that the self-propelled lawn mower has a turning tendency, the self-propelled lawn mower is controlled to turn with a travel motion parameter, and the travel motion parameter is less than a motion tendency parameter.

[0036] In the above system, the motion sensor can at least measure the motion trend parameters of two dimensions within the travel plane of the self-propelled lawn mower.

[0037] Reference Figure 3 , execute step S11, synchronously drive the driving wheels on both sides of the self-propelled lawn mower; measure the motion trend parameter of the self-propelled lawn mower; if the self-propelled lawn mower has a turning trend, execute step S12, control the self-propelled lawn mower to turn with the travel motion parameter, and the travel motion parameter is less than the motion trend parameter; execute step S13, repeat the first step to the second step until the drive of the self-propelled lawn mower is turned off.

[0038] Figure 4 This is a power steering control method using angular acceleration as a parameter of the present invention. In one embodiment, the motion trend parameter includes the actual angular acceleration α1 of the self-propelled lawn mower; if the self-propelled lawn mower has a turning trend, the travel motion parameter is the travel angular acceleration α2, and the self-propelled lawn mower is driven to travel at the travel angular acceleration α2, and the travel angular acceleration α2 is less than the actual angular acceleration α1, so that the self-propelled lawn mower travels at a speed slightly less than the actual angular acceleration α1 of the self-propelled lawn mower given by the user. After the user has a preliminary rotation control of the self-propelled lawn mower, the control steering of the self-propelled lawn mower can be reduced or canceled, the thrust for steering the self-propelled lawn mower is reduced, and the actual angular acceleration α1 is reduced. Because the travel motion parameter, i.e., the travel angular acceleration α2, is set to be smaller than the motion trend parameter, i.e., the actual angular acceleration α1, the user controls to reduce the value of the actual angular acceleration α1, and the control module 5 controls the travel angular acceleration α2 to follow the actual angular acceleration α1 according to the algorithm, so that the travel angular acceleration α2 is smaller than the actual angular acceleration α1, until it is reduced to zero and returns to the straight-ahead state. In this way, the self-propelled lawn mower can automatically complete the return action to complete the steering action of the self-propelled lawn mower, and the user only needs to apply a weak angular acceleration to the self-propelled lawn mower to control the machine to rotate at a certain angular velocity. When the person relaxes the force on his hand after turning to the correct position, the angular velocity will gradually decrease until it goes straight, thereby facilitating the user's steering control of the self-propelled lawn mower and reducing the burden on the user.

[0039] Reference Figure 4 , execute step S21, synchronously drive the driving wheels on both sides of the self-propelled lawn mower, and calculate the actual angular acceleration of the self-propelled lawn mower; execute step S22, if the self-propelled lawn mower has a turning tendency, control the self-propelled lawn mower to turn with a travel angular acceleration, and the travel angular acceleration is less than the actual angular acceleration; execute step S23, repeat the first step to the second step until the drive of the self-propelled lawn mower is turned off.

[0040] Optionally, the control module 5 controls the travel angular acceleration α2 and the actual angular acceleration α1 to operate in a functional relationship, such as f(α2)=α1-m, where m is a certain value.

[0041] Figure 5 This is a power steering control method using angular velocity as a parameter of the present invention. In one embodiment, the motion trend parameter includes the actual angular velocity ω1 of the self-propelled lawn mower; if the self-propelled lawn mower has a turning tendency, the travel motion parameter is the travel angular velocity ω2, and the control module 50 drives the self-propelled lawn mower to travel at a travel angular acceleration α2, and the travel angular acceleration α2 is less than the actual angular velocity ω1, so that the self-propelled lawn mower travels at a speed slightly less than the actual angular velocity ω1 of the self-propelled lawn mower given by the user. After the user has a preliminary rotation control of the self-propelled lawn mower, the control steering of the self-propelled lawn mower can be reduced or canceled, the steering thrust of the self-propelled lawn mower can be reduced, and the actual angular velocity ω1 is reduced. Because the travel motion parameter, i.e., the travel angular velocity ω2, is set to be smaller than the motion trend parameter, i.e., the actual angular acceleration α1, the user controls to reduce the value of the actual angular velocity ω1, and the control module 50 controls the travel angular velocity ω2 to follow the actual angular velocity ω1 according to the algorithm, so that the travel angular velocity ω2 is smaller than the actual angular velocity ω1, until it is reduced to zero and returns to the straight-ahead state. In this way, the self-propelled lawn mower can automatically complete the return action to complete the steering action of the self-propelled lawn mower, and the user only needs to apply a weak angular acceleration to the self-propelled lawn mower to control the machine to rotate at a certain angular velocity. When the person relaxes the force on his hand after turning to the correct position, the angular velocity will gradually decrease until it goes straight, thereby facilitating the user's steering control of the self-propelled lawn mower and reducing the burden on the user.

[0042] Reference Figure 5 , execute step S31, synchronously drive the driving wheels on both sides of the self-propelled lawn mower, and calculate the actual angular velocity of the self-propelled lawn mower; execute step S32, if the self-propelled lawn mower has a turning tendency, control the self-propelled lawn mower to turn at a travel angular velocity, and the travel angular velocity is less than the actual angular velocity; execute step S33, repeat the first step to the second step until the drive of the self-propelled lawn mower is turned off.

[0043] Optionally, the control module 50 controls the travel angular velocity ω2 and the actual angular velocity ω1 to operate in a functional relationship, such as f(ω2)=ω1-n, where n is a certain value.

[0044] Specifically, the angular acceleration α2 or angular velocity ω2 is to adjust the speed ratio between the speed of the driving wheel on the positive side of the actual angular acceleration α1 and the speed of the driving wheel on the reverse side in the self-propelled lawn mower, so as to generate the second angular velocity ω2 for the lawn mower to turn autonomously, so that ω2 never exceeds the actual angular velocity ω1. In this way, when the lawn mower gradually turns to the correct direction, the acceleration pushed by the person gradually decreases, and the actual angular velocity ω1 of the machine rotation also gradually decreases. The second angular velocity ω2 can change with the actual angular velocity ω1 and gradually decrease to 0. At this time, the lawn mower turns to the required direction and resumes straight driving. The adjustment of the angular velocity of the lawn mower is mainly achieved by controlling the single-sided motor to adjust the speed difference or speed ratio.

[0045] The motion trend parameters are stored in the storage device for controlling the operation of the self-propelled lawn mower.

[0046] Combination Figure 3 The present invention first provides a power steering control method for a self-propelled lawn mower, the steps comprising: The first step is to synchronously drive the driving wheels on both sides of the self-propelled lawn mower; and measure the motion trend parameters of the self-propelled lawn mower; The second step is to control the self-propelled lawn mower to turn with a travel motion parameter if the self-propelled lawn mower has a turning tendency, and the travel motion parameter is less than the motion tendency parameter; If the movement trend parameter does not have a turning trend, then maintain or return to the first step; The third step is to repeat the first step to the second step until the drive of the self-propelled lawn mower is turned off.

[0047] The motion trend parameter includes the actual angular acceleration α1 of the self-propelled lawn mower. In the second step, if the self-propelled lawn mower has a turning tendency, the step of controlling the self-propelled lawn mower to turn with the traveling motion parameter includes: The traveling motion parameter is a traveling angular acceleration α2, and the self-propelled lawn mower is driven to travel at the traveling angular acceleration α2, and the traveling angular acceleration α2 is smaller than the actual angular acceleration α1.

[0048] Optionally, the motion trend parameter includes an actual angular velocity ω1 of the self-propelled lawn mower; In the second step, if the self-propelled lawn mower has a turning tendency, the step of controlling the self-propelled lawn mower to turn with a travel motion parameter includes: the travel motion parameter is a travel angular velocity ω2, driving the self-propelled lawn mower to travel at a travel angular velocity ω2, and the travel angular velocity ω2 is less than the actual angular velocity ω1.

[0049] In the scheme of the present invention, one of the cores is to adjust the speed ratio between the speed of the driving wheel on the positive side of the actual angular acceleration α1 and the speed of the driving wheel on the reverse side in the self-propelled lawn mower, so as to generate another second angular velocity ω2 for the lawn mower to turn autonomously, so that ω2 never exceeds the actual angular velocity ω1. In this way, when the lawn mower gradually turns to the correct direction, the acceleration pushed by the person gradually decreases, and the actual angular velocity ω1 of the machine rotation also gradually decreases. The second angular velocity ω2 can change with the actual angular velocity ω1 and gradually decrease to 0. At this time, the lawn mower turns to the required direction and resumes straight driving. The adjustment of the angular velocity of the lawn mower is mainly achieved by controlling the single-side motor to adjust the speed difference or speed ratio.

[0050] In specific use, when a person turns the machine with force and detects that the actual angular acceleration α1 exceeds the preset angular acceleration value α0, the machine starts to automatically turn at an angular velocity of ω2. However, since ω2 is less than ω1, the actual rotation angle of the machine does not meet the rotation speed that the person wants the machine to reach, so the person will continue to apply a certain amount of force to increase the angular velocity; when the machine rotates fast enough, the person will relax the force on his hand, and in the absence of external force, the actual angular velocity ω1 gradually decreases, and the angular velocity ω2 of the rotation remains lower than the measured angular velocity ω1, so the machine will follow the angular velocity ω1 and gradually reduce the rotation speed. In such a closed-loop control mechanism, people only need to apply a weak force to control the machine to rotate autonomously at a certain angular velocity. When the person relaxes the force on his hand after turning to the correct position, the angular velocity will gradually decrease until it goes straight, realizing "power steering".

[0051] The ratio of the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower is determined according to the following steps: Step A1, measuring the actual angular velocity ω1 and the actual velocity v1 of the self-propelled lawn mower when it is moving, calculating the rotation radius r= v1 / ω1 of the self-propelled lawn mower when it is moving, and determining the rotation center O of the self-propelled lawn mower when it is moving; Step A2, calculating the ratio k of the distances from the driving wheels on both sides of the self-propelled lawn mower to the rotation center O; Step A3: The ratio of the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower is not greater than the ratio k of the distances from the driving wheels on both sides of the self-propelled lawn mower to the rotation center O.

[0052] Furthermore, in the above method, in the second step, the ratio of the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower follows the magnitude of the actual angular acceleration α1. Thus, the speed of the lawn mower's steering can be controlled by the magnitude of the steering force applied by a person, which is more in line with the user's operating habits. Furthermore, the ratio of the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower follows the magnitude of the traveling motion parameter.

[0053] Figure 6 This is a power steering control method using acceleration as a parameter of the present invention. Figure 6 As shown, the motion trend parameter also includes a first acceleration a1 of the self-propelled lawn mower in the moving direction; the preset value corresponding to the first acceleration a1 is the acceleration preset value a0; In the second step, the step of cooperatively controlling the rotation speed of the driving wheels on both sides of the self-propelled lawn mower to drive the moving state of the self-propelled lawn mower to follow the motion trend parameter also includes: synchronously driving the driving wheels on both sides of the self-propelled lawn mower with a second acceleration a2, wherein the second acceleration a2 is less than the first acceleration a1, and the second acceleration a2 and the first acceleration a1 have a functional relationship.

[0054] When the first acceleration a1 is greater than the preset acceleration value a 0， The driving wheels on both sides of the self-propelled lawn mower are driven synchronously at a second acceleration a2.

[0055] Here, the response to the first acceleration a1 can be used in the process of walking in a straight line, or, in combination with the above-mentioned judgment and response to the first acceleration a1, the "assistance" function can be realized while turning. When it is judged that the first acceleration a1 exceeds the preset acceleration value a0, the speed of the automatic forward movement of the cart can be controlled accordingly according to the change of the user's thrust, so that the user can control the automatic forward movement of the cart with very little force. When acceleration is required, it only needs to continue to apply thrust, and the speed of the motors on both sides can be adjusted through the following effect of the second acceleration a2 on the first acceleration a1, so that the lawn mower can automatically "keep up" with this change. In this way, the forward speed of the lawn mower can be freely controlled, the operation is more flexible, and automatic closed-loop control is realized.

[0056] Reference Figure 6 , a method for controlling power steering using acceleration as a parameter is provided. Step S41 is executed to synchronously drive the driving wheels on both sides of the self-propelled lawn mower, and a first acceleration of the self-propelled lawn mower is measured; if the self-propelled lawn mower has a turning tendency, step S42 is executed to control the self-propelled lawn mower to turn at a second acceleration, and the second acceleration is less than the first acceleration; step S43 is executed to repeat the first step to the second step until the drive of the self-propelled lawn mower is turned off.

[0057] In one embodiment, a preset angular acceleration value α0 corresponding to the actual angular acceleration α1 is provided in the storage device. When the actual angular acceleration α1 is greater than the preset angular acceleration value α0, it is determined that the self-propelled lawn mower has a turning tendency, and the control module 50 controls the differential operation of the driving wheels on both sides, thereby generating a corresponding angular acceleration α2.

[0058] Figure 7 This is another power steering control method of the present invention. When the motion trend parameter is greater than a preset value, it is determined that the self-propelled lawn mower has a turning trend, and when the motion trend parameter is less than the preset value, the self-propelled lawn mower is controlled to go straight.

[0059] Specifically, Figure 7 As shown, step S51 is executed to synchronously drive the driving wheels on both sides of the self-propelled lawn mower, measure the motion trend parameter of the self-propelled lawn mower, and step S52 is executed to determine that the self-propelled lawn mower has a turning trend when the motion trend parameter is greater than a preset value, and control the self-propelled lawn mower to turn. Or step S53 is executed to control the self-propelled lawn mower to execute when the self-propelled lawn mower is less than a preset value. Step S54 is executed to repeat the first to third steps until the drive of the self-propelled lawn mower is turned off.

[0060] Furthermore, the preset value is stored in a storage device for controlling the operation of the self-propelled lawn mower.

[0061] Furthermore, taking into account the interference of the uneven ground on the data collected by the lawn mower's motion sensor, in order to avoid misoperation or misjudgment of the lawn mower's motion state, in the above method, the preset angular acceleration value α0 should be at least greater than the actual angular acceleration α1' measured when the self-propelled lawn mower is moving in a straight line.

[0062] If the actual angular acceleration α1 detected by manually turning the handrail to adjust the direction of the lawn mower is greater than the preset value of angular acceleration α0, it means that the person really wants to rotate the machine. At this time, the speed difference of the motors on both sides needs to be controlled. Specifically, the automatic advancement of the inner wheel can be stopped, or the outer wheel can be accelerated, or the speed of the inner wheel can be reduced while the speed of the outer wheel is increased, or the speed of the wheels on both sides can be reduced at the same time, but the speed of the inner wheel is reduced more, so that the machine can turn. No manual effort is required in this process, and the machine can be fully controlled to turn at a certain angle. If the actual angular acceleration α1<the preset value of angular acceleration α0, it can be judged that the person does not want to turn, but may just fail to keep a straight line, or want to slightly adjust the route, or the bumpy road surface causes the motion sensor of the machine to detect a certain angular velocity error, so the machine needs to continue to keep going straight. If the machine is turning and has turned to the required angle, the person only needs to use a little force to straighten it, which will make the actual angular acceleration α1<the preset value of angular acceleration α0, and the machine can return to the first step of synchronously driving the motors on both sides of the self-propelled lawn mower to achieve "return to the center" and keep going straight.

[0063] This mechanism can also be used to control the stability of the machine body, so that the machine keeps moving straight and avoids the arc caused by human error. When the machine detects a slight deviation from the straight line, it will definitely detect a certain angular velocity, but this angular velocity will be less than a certain preset value we set. At this time, we can make corrections for this angular velocity. Keep the machine moving straight. Therefore, the lawn mower using the technology of the present invention can ensure a stable and straight direction of travel even when encountering a bumpy route, and the mowing effect is more beautiful.

[0064] As the second core point of the solution of the present invention, here, the rotation speed of the double-sided driving wheels in the self-propelled lawn mower is adjusted at the same time to generate a second acceleration a2 for accelerating or decelerating the lawn mower. The second acceleration a2 is always not greater than the first acceleration a1. In this way, when the lawn mower is gradually adjusted to the required speed, the acceleration of the human push gradually decreases, and the first acceleration a1 of the machine rotation also gradually decreases. The second acceleration a2 can change with the first acceleration a1 and gradually decrease to 0. At this time, the lawn mower turns to the required speed and restores the uniform speed. The adjustment of the acceleration of the lawn mower is mainly achieved by synchronously controlling the motors on both sides and synchronously adjusting the speed changes on both sides.

[0065] Similarly, the preset value corresponding to the actual acceleration a1 is the acceleration preset value a0; specifically, in the above method, the second acceleration a2 is not greater than the first acceleration a1.

[0066] In the above method, in the second step, the second acceleration a2 is a fixed value or changes with the magnitude of the first acceleration a1.

[0067] The driving wheels on both sides of the self-propelled lawn mower are driven synchronously with a second acceleration a2, wherein the second acceleration a2 is smaller than the first acceleration a1, and the second acceleration a2 and the first acceleration a1 have a functional relationship.

[0068] In another embodiment, the driving wheels on both sides of the self-propelled lawn mower are driven synchronously with a second acceleration a2, wherein the second acceleration a2 is smaller than the first acceleration a1, and the second acceleration a2 is a constant value.

[0069] Combination Figure 2 Based on the above method, the present invention also correspondingly proposes a power steering control system for a self-propelled lawn mower, comprising: At least two driving wheels 10 and at least two motors 20 are respectively arranged on both sides of the self-propelled lawn mower, and the motors 20 are respectively connected to and drive the driving wheels 10 on one side of the self-propelled lawn mower; including: at least one motion sensor 30, the motion sensor 30 is arranged on the self-propelled lawn mower, and is used to measure the motion trend parameters of the self-propelled lawn mower; a control module 50, the control module is connected to the motion sensor and the motor at the same time; the control module is used to coordinately control the rotation speed of the motors connected to the driving wheels on both sides of the self-propelled lawn mower when the self-propelled lawn mower has a turning trend, and control the self-propelled lawn mower to turn with the travel motion parameter, and the travel motion parameter is less than the motion trend parameter.

[0070] Specifically, when the actual angular acceleration α1 of the self-propelled lawn mower exceeds the preset angular acceleration value α0, the "parameter value for driving the self-propelled lawn mower" specifically corresponds to the ratio of the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower. The rotation speed ratio "is not greater than the value of the motion trend parameter", that is, the second angular velocity ω2 of the self-driving lawn mower caused by the difference in the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower does not exceed the actual angular velocity ω1 of the self-propelled lawn mower measured by the motion sensor.

[0071] Specifically, when the first acceleration a1 of the self-propelled lawn mower exceeds the acceleration preset value a0, the "parameter value for driving the self-propelled lawn mower to move forward" specifically corresponds to the second acceleration a2 for driving the driving wheels on both sides of the self-propelled lawn mower. The second acceleration a2 "is not greater than the value of the motion trend parameter", that is, the second acceleration a2 is not greater than the first acceleration a1.

[0072] Furthermore, in the above system, a bidirectional overrunning clutch 60 is connected between the motor and the drive wheel connected thereto.

[0073] The driving shaft of the two-way overrunning clutch 60 is connected to the motor, and the driven shaft is connected to the driving wheel. Therefore, during normal travel, the motor is connected to the driving shaft to rotate and drive the driven shaft, which can provide bidirectional drive for the driving wheel; when adjusting the travel state of the lawn mower, when the speed of the driving shaft connected to the motor is adjusted and stopped, the driven shaft can be driven by the driving wheel to rotate freely in both directions, and the speed can be smoothly changed; when the driving shaft rotates, when the lawn mower is manually pushed and the speed of the driving wheel exceeds the speed of the motor, the speed generated by the manual push of the lawn mower can be driven by the driven shaft through the driving wheel to achieve the same direction overtaking relative to the driving shaft. Therefore, when the motor speed changes, it can avoid excessive torque on the motor shaft due to the delay in the speed of the driving wheel, thereby protecting the motor. Therefore, when the motor speed changes, it can also avoid the resistance to the driving wheel caused by the hysteresis of the motor speed when pushed by human power, and avoid the motor affecting the speed of the driving wheel, so that the lawn mower can travel more smoothly, and the driving wheel can smoothly change speed when turning or adjusting the speed, so that the lawn mower body can travel more stably, thereby further improving the mowing effect.

[0074] Combination Figure 3 The present invention also proposes a self-propelled lawn mower, comprising: a body 100, a support wheel 70, wherein the support wheel is arranged under the body for supporting the body; a mowing mechanism 80, wherein the mowing mechanism is arranged under the body for mowing; a control device 90, wherein the control device is used to control the operation of the self-propelled lawn mower; and further comprising the power steering control system as described above, wherein the motion sensor 30 is arranged between the driving wheels 10 on both sides of the self-propelled lawn mower; a control module 50 in the power steering control system is connected to the control device 90, and the control device 90 includes an interface for setting the preset value in the control module, including the angular acceleration preset value α0 or the acceleration preset value a0.

[0075] It is worth mentioning that when judging the steering trend based on the motion trend parameters above, at least one of the above motion trend parameters such as the first acceleration a1, the actual angular velocity ω1 or the actual angular acceleration α1 can be collected, and the acquired motion trend parameters can be used to control the movement of the self-propelled lawn mower. Alternatively, multiple motion trend parameters can be collected, any set of at least two or more of the first acceleration a1, the actual angular velocity ω1 or the actual angular acceleration α1, and then the self-propelled lawn mower can be controlled for power steering based on all acquired parameters.

[0076] In summary, the present invention further provides a power steering control system for a self-propelled lawn mower, comprising: At least two driving wheels and at least two motors are respectively arranged on both sides of the self-propelled lawn mower, and the motors are respectively connected to and drive the driving wheels on one side of the self-propelled lawn mower; it also includes: at least one motion sensor, the motion sensor is arranged on the self-propelled lawn mower, and is used to measure the motion trend parameters of the self-propelled lawn mower; a control module, the control module is connected to the motion sensor and the motor at the same time; the control module is used to coordinately control the rotation speed of the motors connected to the driving wheels on both sides of the self-propelled lawn mower when the self-propelled lawn mower has a turning trend, and control the self-propelled lawn mower to turn with the travel motion parameter, and the travel motion parameter is less than the motion trend parameter.

[0077] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A power steering control method for a self-propelled lawn mower, characterized in that the steps include: The first step is to synchronously drive the driving wheels on both sides of the self-propelled lawn mower to measure the motion trend parameters of the self-propelled lawn mower; The second step is to control the self-propelled lawn mower to turn with a travel motion parameter if the self-propelled lawn mower has a turning tendency, and the travel motion parameter is less than the motion tendency parameter; If the movement trend parameter does not have a turning trend, then maintain or return to the first step; The third step is to repeat the first step to the second step until the drive of the self-propelled lawn mower is turned off.

2. The power steering control method for a self-propelled lawn mower according to claim 1, characterized in that: The motion trend parameter includes the actual angular acceleration α1 of the self-propelled lawn mower In the second step, if the self-propelled lawn mower has a turning tendency, the step of controlling the self-propelled lawn mower to turn with the travel motion parameter includes: The traveling motion parameter is a traveling angular acceleration α2, and the self-propelled lawn mower is driven to travel at the traveling angular acceleration α2, and the traveling angular acceleration α2 is smaller than the actual angular acceleration α1.

3. A power steering control method for a self-propelled lawn mower as claimed in claim 1, characterized in that: The motion trend parameter includes the actual angular velocity ω1 of the self-propelled lawn mower; In the second step, if the self-propelled lawn mower has a turning tendency, the step of controlling the self-propelled lawn mower to turn with the travel motion parameter includes: The traveling motion parameter is a traveling angular velocity ω2, which drives the self-propelled lawn mower to travel at a traveling angular velocity ω2, and the traveling angular velocity ω2 is less than an actual angular velocity ω1.

4. The power steering control method for a self-propelled lawn mower according to claim 3, characterized in that: In the second step, the ratio of the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower is determined according to the following steps: Step A1, measuring the actual angular velocity ω1 and the actual speed v1 of the self-propelled lawn mower when traveling, calculating the rotation radius r = v1 / ω1 when the self-propelled lawn mower is traveling, determining the center of rotation O when the self-propelled lawn mower is traveling; Step A2, calculating the ratio k of the distances from the driving wheels on both sides of the self-propelled lawn mower to the rotation center O; Step A3: The ratio of the speeds of the driving wheels on both sides of the self-propelled lawn mower is not greater than the ratio k of the distances from the driving wheels on both sides of the self-propelled lawn mower to the rotation center O.

5. The power steering control method for a self-propelled lawn mower according to claim 2 or 3, characterized in that: The ratio of the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower changes with the magnitude of the traveling motion parameter.

6. The power steering control method for a self-propelled lawn mower according to claim 1, characterized in that: The self-propelled lawn mower includes a preset value. When the motion trend parameter is greater than the preset value, it is determined that the self-propelled lawn mower has a turning trend. When the motion trend parameter is less than the preset value, the self-propelled lawn mower is controlled to move straight.

7. The power steering control method for a self-propelled lawn mower according to claim 6, characterized in that: The motion trend parameter also includes a first acceleration a1 of the self-propelled lawn mower in the moving direction; the preset value corresponding to the actual acceleration a1 is the acceleration preset value a0; In the second step, the step of cooperatively controlling the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower to drive the self-propelled lawn mower to follow the motion trend parameter also includes: The driving wheels on both sides of the self-propelled lawn mower are driven synchronously with a second acceleration a2, wherein the second acceleration a2 is smaller than the first acceleration a1, and the second acceleration a2 and the first acceleration a1 have a functional relationship.

8. The power steering control method for a self-propelled lawn mower according to claim 6, characterized in that: The motion trend parameter also includes a first acceleration a1 of the self-propelled lawn mower in the moving direction; the preset value corresponding to the actual acceleration a1 is the acceleration preset value a0; In the second step, the step of cooperatively controlling the rotation speeds of the driving wheels on both sides of the self-propelled lawn mower to drive the self-propelled lawn mower to follow the motion trend parameter also includes: The driving wheels on both sides of the self-propelled lawn mower are driven synchronously with a second acceleration a2, wherein the second acceleration a2 is smaller than the first acceleration a1, and the second acceleration a2 is a constant value.

9. A power steering control system for a self-propelled lawn mower, comprising: At least two driving wheels and at least two motors are respectively arranged on both sides of the self-propelled lawn mower, and the motors are respectively connected to and drive the driving wheels on one side of the self-propelled lawn mower; it is characterized in that it also includes: at least one motion sensor, the motion sensor is arranged on the self-propelled lawn mower, and is used to measure the motion trend parameters of the self-propelled lawn mower; a control module, the control module is connected to the motion sensor and the motor at the same time; the control module is used to coordinately control the rotation speed of the motors connected to the driving wheels on both sides of the self-propelled lawn mower when the self-propelled lawn mower has a turning trend, and control the self-propelled lawn mower to turn with the travel motion parameter, and the travel motion parameter is less than the motion trend parameter.

10. The power steering control system for a self-propelled lawn mower according to claim 9, characterized in that: A bidirectional overrunning clutch is also connected between the motor and the driving wheel connected thereto.

11. The power steering control system for a self-propelled lawn mower according to claim 10, characterized in that: The self-propelled lawn mower includes a preset value. When the motion trend parameter is greater than the preset value, it is determined that the self-propelled lawn mower has a turning trend. When the motion trend parameter is less than the preset value, the self-propelled lawn mower is controlled to move straight.

12. A self-propelled lawn mower comprising: body, Support wheels, the support wheels are arranged under the fuselage and are used to support the fuselage; A mowing mechanism, which is arranged under the machine body and is used for mowing; A control device, the control device is used to control the operation of the self-propelled lawn mower; It is characterized in that it also includes the power steering control system as claimed in claim 9; Wherein, the motion sensor is arranged between the driving wheels on both sides of the self-propelled lawn mower; The control module in the power steering control system is connected to the control device, and the control device includes an interface for setting the preset value in the control module.

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