A motion device capable of moving along a target trajectory

Abstract

The present invention belongs to the technical field of intelligent transportation equipment, and discloses a motion device that can move along a target track. An obstacle avoidance module is provided at the front end of the motion device, and a motion module, a deviation correction module and a control module are installed in a square installation area on the side of the bottom plate facing the ground. The motion module includes four Furley wheels installed diagonally for moving forward and for deviation correction or obstacle avoidance. The deviation correction module includes a tracking sensor group and a deviation correction sensor group, which are used to determine whether the motion device deviates from the target track. The obstacle avoidance module is used to determine whether there is an obstacle in front of the motion device. The motion device is used to control the motion device to perform adaptive deviation correction or obstacle avoidance according to the information of the sensors in the deviation correction module or the obstacle avoidance module. The ingenious design of the wheel structure of the motion device enables it to move from a certain position to any direction on a two-dimensional plane. Deviation correction or obstacle avoidance can be achieved without changing the posture of the vehicle body or performing a differential algorithm. The control method is simple and can be applied to the fields of intelligent sorting, intelligent transportation, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of intelligent transportation equipment, and in particular relates to a motion device capable of moving along a target trajectory. Background Art

[0002] With the current cloud-based shopping model and the continuous development and progress of intelligent technology, logistics carts, sorting robots and other motion devices that can move along the target trajectory are widely used in the modern logistics industry. This type of motion device relies on sensors to move along the target trajectory by tracking, but under normal circumstances, it will deviate to a certain extent due to uneven road conditions. At this time, it is necessary to correct the deviation so that it can return to the target trajectory and continue to move forward. Usually, the wheels of this type of motion device are installed in the direction of travel, and the deviation is corrected by differential tracking. For this type of differential correction method under the traditional installation structure, on the one hand, the size of the differential is difficult to determine and control; on the other hand, it is necessary to ensure that the PID response of the motor is fast enough, which is more complicated to control.

[0003] In addition, when encountering obstacles, the algorithms for traditional motion devices to quickly bypass or avoid obstacles are relatively complex, and they need to reverse and re-pass the sensor detection and avoid obstacles. In this way, it is necessary to ensure that the sensor has no blind spots, otherwise the program will fall into an infinite loop. Not only that, even with an excellent control algorithm, when a wheel of a traditional motion device breaks down, its self-correction function will be lost. Therefore, traditional motion devices have poor adaptability to emergencies. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a motion device that can move along a target trajectory. During the process of the motion device moving at a uniform speed at a first speed, through the coordination design of wheels in different directions and the correction speed design, when the motion device deviates from the target track, it can quickly and stably perform automatic correction to return to the target trajectory and continue to move at the first uniform speed. When encountering an obstacle, it can simply and quickly avoid the obstacle and return to the target trajectory.

[0005] The present invention provides a motion device that can move along a target track. The motion device has an adaptive deviation correction function. The adaptive deviation correction means that when the motion device deviates from the target track during the process of uniformly moving at a first speed, the motion device can automatically correct the deviation to return to the target track and continue to move at the first speed. A motion module, a deviation correction module and a control module are installed in a square installation area on the side of the bottom plate of the motion device facing the ground.

[0006] The motion module comprises a first wheel, a second wheel, a third wheel and a fourth wheel; the first wheel and the fourth wheel are symmetrically mounted at the front end of the square mounting area relative to the first central axis, and the axis of the fourth wheel is perpendicular to the axis of the first wheel and the first central axis; the second wheel and the third wheel are symmetrically mounted at the rear end of the square mounting area relative to the first central axis, and the axis of the third wheel is perpendicular to the axis of the second wheel and the first central axis;

[0007] The first central axis is the central axis of the square installation area;

[0008] The motion module further includes a first drive motor, a second drive motor, a third drive motor and a fourth drive motor for driving the first wheel, the second wheel, the third wheel and the fourth wheel respectively;

[0009] The deviation correction module includes a tracking sensor group and a deviation correction sensor group arranged between the first wheel and the fourth wheel;

[0010] The tracking sensor group includes a plurality of sensors installed symmetrically to the first central axis, and the deviation correction sensor group includes a plurality of sensors symmetrically arranged on both sides of the tracking sensor group;

[0011] The control module is connected to the tracking sensor group and the deviation correction sensor group signals, and is used to control the motion device to start deviation correction when the sensors in the deviation correction sensor group sense the target trajectory until all the sensors in the tracking sensor group sense the target trajectory.

[0012] Furthermore, the first wheel, the second wheel, the third wheel and the fourth wheel are all Furley wheels.

[0013] Furthermore, the target track is a target track with a constant width.

[0014] Furthermore, the width of the tracking sensor group is the distance between the leftmost sensor and the rightmost sensor, and the width of the tracking sensor group is equal to or slightly larger than the width of the target track.

[0015] Furthermore, the tracking sensor group includes two tracking sensors.

[0016] Furthermore, controlling the motion device to correct the deviation to the target trajectory comprises the following steps:

[0017] S1. When the sensor in the deviation correction sensor group senses the target trajectory, the first drive motor is controlled to impart a second speed to the first wheel; the direction of the second speed is perpendicular to the first speed and points to the sensor that senses the target trajectory;

[0018] The range of the value of the second speed is as follows:

[0019]

[0020] Wherein, v1 is the first speed, v2 is the second speed, θ is the angle between the line connecting the outermost sensor of the deviation correction sensor group and the center of the square installation area and the first central axis; s is the sensor spacing; t is the detection interval time of the sensor;

[0021] S2. When all sensors in the tracking sensor group sense the target track, control the first drive motor to stop the first wheel from rotating.

[0022] Furthermore, the motion device further comprises an obstacle avoidance module, which is arranged at the front end of the motion device and is used to sense whether there is an obstacle in front of the motion device;

[0023] The control device is connected to the obstacle avoidance module signal, and is used to control the motion device to avoid the obstacle when the obstacle avoidance module senses that there is an obstacle in front.

[0024] Furthermore, when the obstacle avoidance module senses that there is an obstacle ahead, controlling the motion device to avoid the obstacle comprises the following steps:

[0025] S1. When the obstacle avoidance module senses the presence of an obstacle in front, the third drive motor and the fourth drive motor are controlled to stop the third wheel and the fourth wheel from rotating;

[0026] S2. Controlling the first drive motor and the second drive motor to rotate the first wheel and the second wheel so that the motion device moves at a third speed in a preset direction perpendicular to the target trajectory;

[0027] S3. When the obstacle avoidance module senses no obstacle ahead, the first drive motor and the second drive motor are controlled to stop the first wheel and the second wheel from rotating, and after a preset time, the first drive motor and the second drive motor are controlled to rotate the first wheel and the second wheel to make the motion device move in a direction opposite to the preset direction at a third speed until the motion device returns to the target trajectory;

[0028] S4. Control the first drive motor and the second drive motor to stop the first wheel and the second wheel from rotating, and then control the third drive motor and the fourth drive motor to rotate the third wheel and the fourth wheel, so that the motion device continues to move forward along the target trajectory at the first speed.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] 1) The motion device provided by the present invention can realize motion from one position to any direction on a two-dimensional plane without changing the posture of the vehicle body, thereby improving space utilization and intelligence.

[0031] 2) The motion device provided by the present invention can provide a better path planning solution under more complex road conditions. For example, when passing a right-angle turn or directly hitting an obstacle, there is no need to use a complex differential algorithm to achieve the turning of the car. It only needs to use the first wheel and the second wheel for driving and the third wheel and the fourth wheel for correction, and the car will travel in a direction perpendicular to the first central axis.

[0032] 3) The motion device provided by the present invention can also make use of only the remaining three wheels for complementary correction to achieve the original moving target when one wheel of the vehicle is damaged, and has strong adaptability.

[0033] 4) The motion device provided by the present invention can achieve stable deviation correction by only giving the first wheel a second speed (within a limited range), without considering and calculating the differential speed between the two wheels to achieve deviation correction, and the control is relatively simple.

[0034] 5) The adaptive deviation-correcting motion device capable of moving along a target trajectory provided by the present invention can directly move in a direction perpendicular to the first central axis when encountering an obstacle ahead, thereby effectively avoiding the obstacle while ensuring that the posture of the vehicle body does not change. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the structure of a square installation area of ​​a bottom plate of a sports device provided by an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a square installation area of ​​a bottom plate when the motion device provided by an embodiment of the present invention moves along a target trajectory;

[0037] Figure 3 A schematic diagram of a square installation area of ​​a bottom plate when a motion device provided by an embodiment of the present invention deviates from a target trajectory;

[0038] Figure 4 A speed analysis diagram of a motion device provided by an embodiment of the present invention when the motion device deviates from a target trajectory and cannot be corrected back to the target trajectory;

[0039] Figure 5 A speed analysis diagram of a motion device provided by an embodiment of the present invention when the motion device deviates from a target trajectory and can be corrected back to the target trajectory;

[0040] Figure 6 A speed analysis diagram of a motion device provided by an embodiment of the present invention when the angle of deviation from the target trajectory is small;

[0041] Figure 7A schematic diagram of a square installation area of ​​a bottom plate when sensors e and f of a motion device provided by an embodiment of the present invention are above a target track;

[0042] Figure numerals: 101, first wheel; 102, second wheel; 103, third wheel; 104, fourth wheel; 2, square installation area; 3, tracking sensor group; 4, deviation correction sensor group. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described in conjunction with specific embodiments and drawings.

[0044] The present invention provides a motion device that can move along a target track, the width of the target track remains unchanged, and the motion device has an adaptive deviation correction function, which means that when the motion device deviates from the target track during the process of uniform motion at a first speed, it can automatically correct the deviation to return to the target track and continue to move at the first speed. Figure 1 As shown, a motion module, a correction module and a control module are installed in a square installation area 2 on the side of the bottom plate of the motion device facing the ground. The first central axis is the central axis AA' of the square installation area. The motion module includes a first wheel 101, a second wheel 102, a third wheel 103 and a fourth wheel 104. The motion module also includes a first drive motor, a second drive motor, a third drive motor and a fourth drive motor for driving the first wheel 101, the second wheel 102, the third wheel 103 and the fourth wheel 104 respectively. The third wheel 103 and the fourth wheel 104 are respectively installed at the lower right corner position and the upper left corner position of the square installation area parallel to the first central axis, and are used to give the motion device a speed of travel (forward movement) under the driving action of the third drive motor and the fourth drive motor. The first wheel 101 and the second wheel 102 are installed at the upper right corner position and the lower left corner position of the square installation area perpendicular to the first central axis, and the first wheel 101 is used to give the motion device a speed of moving to the right or left under the driving action of the first drive motor. The first wheel 101 and the fourth wheel 104 are symmetrically installed at the front end of the installation area relative to the first center axis, and the axis of the fourth wheel 104 is perpendicular to the axis of the first wheel 101 and the first center axis; the second wheel 102 and the third wheel 103 are symmetrically installed at the rear end of the square installation area relative to the first center axis, and the third wheel 103 is perpendicular to the axis of the second wheel 102 and the first center axis.

[0045] The first wheel 101, the second wheel 102, the third wheel 103 and the fourth wheel 104 are all Furley wheels, which include a driving wheel and a plurality of driven wheels, and the driven wheels are arranged on the driving wheel at intervals in the circumference to reduce the resistance during movement. The Furley wheel of the present invention is also called an omnidirectional wheel, and is purchased from Juxin Zhichuang Technology Co., Ltd.

[0046] The deviation correction module includes a tracking sensor group 3 and a deviation correction sensor group 4 arranged between the first wheel 101 and the fourth wheel 104; the tracking sensor group 3 includes a plurality of sensors installed symmetrically to the first central axis, and the distance between the left edge of the leftmost sensor of the tracking sensor group 3 and the right edge of the rightmost sensor is the width of the tracking sensor group 3. The deviation correction sensor group 4 includes a plurality of sensors symmetrically arranged on both sides of the tracking sensor group 3. The tracking sensor group 3 is used to determine whether the motion device is traveling correctly along the target track. Specifically, when all sensors in the tracking sensor group 3 sense the target track, it indicates that the motion device is moving along the target track; the deviation correction sensor group 4 is used to determine whether the motion device deviates from the target track. Specifically, when the sensors in the deviation correction sensor group 4 sense the target track, it indicates that the motion device has deviated from the target track. The control module is connected to the tracking sensor group 3 and the deviation correction sensor group 4 by signal, and is used to control the motion device to start deviation correction when the sensors in the deviation correction sensor group 4 sense the target track, until all sensors in the tracking sensor group 3 sense the target track, and control the motion device to stop deviation correction.

[0047] In one embodiment of the present invention, Figure 2 As shown, the target track is approximately considered to be a straight road within a shorter distance, and the tracking sensor group 3 includes two sensors, sensor d and sensor e. The distance between the leftmost edge of sensor d and the rightmost edge of sensor e is the width of the tracking sensor group 3. When the motion device moves at a uniform speed along the target track at a first speed, sensor d and sensor e are respectively located directly above the edge lines on both sides of the target track, and are in a sensing state to the target track, that is, the light is on. Sensor d is located above the left edge line of the target track, and sensor e is located above the right edge line of the target track, and is in a sensing state to the target track. The deviation correction sensor group 4 includes six sensors, sensor ac and sensor fh. Sensor ac is set on the left side of sensor d, and sensor fh is set on the right side of sensor e. The sensors in the tracking sensor group 3 and the deviation correction sensor group 4 are all the same sensors, and the sensor spacing is s, that is, the spacing of sensors ah is s.

[0048] When the motion device deviates from the target trajectory, some of the sensors ac and fh will sense the target trajectory and be in a sensing state. Figure 3 In the schematic diagram of the square installation area shown, sensors g and h are located above the target track and are in the sensing state, indicating that the motion device has deviated from the target track. At this time, the control module starts to control the motion device to correct the deviation. Specifically, the first drive motor is controlled to give the first wheel 101 a second speed; the direction of the second speed is perpendicular to the first speed and points to the sensor that senses the target track, that is, the direction of sensor h, as shown in FIG. Figure 5 shown.

[0049] To ensure that the motion device that deviates from the target trajectory can return to the target trajectory through deviation correction, and that the deviation correction process does not swing left and right significantly, the second speed should be limited to a certain range. The specific analysis process is as follows:

[0050] In the initial state, the motion device moves forward at a constant speed v1 along the target trajectory. Figure 3 In the case shown, the sensor h can sense the target trajectory, and the deviation angle is θ, corresponding to Figure 3 In the case of , the value of θ happens to be equal to the angle between the line connecting the sensor h and the center of the square installation area 2 and the first central axis, which is the maximum deviation degree of the motion device, and the second speed v2 is analyzed.

[0051] On the one hand, the second speed v2 cannot be too small, otherwise the deviation correction cannot be achieved.

[0052] like Figure 4 As shown, the angle between the line connecting the sensor h and the center of the square installation area 2 and the first central axis is θ, the speed of the moving device moving forward along the target trajectory is v1, the speed of correcting the deviation perpendicular to the first central axis AA' is v2, the composite speed of v1 and v2 is v, and the angle between the composite speed v and v1 is ɑ, from Figure 4 It can be seen that when α<θ, the resultant velocity v cannot make the moving device return to the target trajectory. Figure 5 It can be seen that only when α>θ can the motion device be corrected to the right front, thus gradually correcting the deviation and returning to the target trajectory. From α>θ, we can get: That is, v2>v1tanθ.

[0053] When the motion device deviates from the target trajectory at a small angle, such as Figure 6 As shown, that is, when the angle β between the target trajectory and the first center axis AA' is <θ, since the angle between the composite velocity v and v1 is ɑ, and α>θ, ɑ must be greater than β, so when v2>v1tanθ, the composite velocity v is able to make the motion device return to the target trajectory.

[0054] On the other hand, the second speed v2 cannot be too large, otherwise the swing amplitude will be large.

[0055] like Figure 7 As shown in the figure, assume that sensor d, sensor e and sensor f are adjacent to each other. When the deviation correction starts, the target track is below sensors e and f. Under ideal conditions without swing, when the sensor detects again, the target track will be below sensors d and e. That is, within the detection interval t of the deviation correction module, the distance s corrected by the motion device is the distance between the two adjacent sensors, that is, the deviation correction is as follows: Figure 2 Position shown.

[0056] Therefore, the second speed v2 cannot exceed If this value is exceeded, the motion device will be in an unstable state with large swings left and right when correcting the deviation.

[0057] According to the above analysis, the range of the second speed value is as follows:

[0058]

[0059] Among them, v1 is the first speed, v2 is the second speed, θ is the angle between the line connecting the outermost correction sensor of the correction sensor group 4 and the center of the square installation area 2 and the first central axis; s is the sensor spacing; t is the detection interval time of the sensor.

[0060] When all sensors in the tracking sensor group 3 detect the target track again, the first driving motor controls the first wheel 101 to stop rotating, and the movement device completes the deviation correction.

[0061] When the motion device does not need to correct deviation, the speed of the first wheel and the second wheel is 0. The Furley wheel has a plurality of driven wheels circumferentially spaced apart on the driving wheel. Therefore, the driven wheels can move along the direction of the first central axis when the driving wheel stops rotating, thereby greatly reducing the resistance of the intelligent tracking motion device when it does not need to correct deviation.

[0062] In one embodiment of the present invention, the motion device further includes an obstacle avoidance module, which is disposed at the front end of the motion device and is used to sense whether there is an obstacle in front of the motion device; the control device is connected to the obstacle avoidance module signal and is used to control the motion device to avoid the obstacle when the obstacle avoidance module senses that there is an obstacle in front. The obstacle is an obstacle that moves relative to the motion device along the target trajectory.

[0063] Specifically, the following steps are included:

[0064] S1. When the obstacle avoidance module senses the presence of an obstacle in front, it controls the third drive motor and the fourth drive motor to stop the third wheel 103 and the fourth wheel 104 from rotating;

[0065] S2. Controlling the first drive motor and the second drive motor to rotate the first wheel 101 and the second wheel 102 so that the motion device moves at a third speed in a preset direction perpendicular to the target trajectory;

[0066] S3. When the obstacle avoidance module senses no obstacle ahead, the first drive motor and the second drive motor are controlled to stop the first wheel 101 and the second wheel 102 from rotating, and after waiting for a preset time, the first drive motor and the second drive motor are controlled to rotate the first wheel 101 and the second wheel 102 to make the motion device move in a direction opposite to the preset direction at a third speed until the motion device returns to the target trajectory;

[0067] S4. Control the third drive motor and the fourth drive motor to rotate the third wheel 103 and the fourth wheel 104, so that the motion device continues to move forward along the target trajectory at the first speed.

[0068] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A motion device capable of moving along a target trajectory, the motion device having an adaptive deviation correction function, wherein the adaptive deviation correction means that when the motion device deviates from the target trajectory during the process of uniformly moving at a first speed, the motion device can automatically correct the deviation to return to the target trajectory and continue to move at the first speed, characterized in that: A motion module, a deviation correction module and a control module are installed in a square installation area (2) on the side of the bottom plate of the motion device facing the ground; The motion module comprises a first wheel (101), a second wheel (102), a third wheel (103) and a fourth wheel (104); the first wheel (101) and the fourth wheel (104) are symmetrically mounted at the front end of the square mounting area (2) relative to a first central axis, and the axis of the fourth wheel (104) is perpendicular to the axis of the first wheel (101) and the first central axis; the second wheel (102) and the third wheel (103) are symmetrically mounted at the rear end of the square mounting area (2) relative to the first central axis, and the third wheel (103) is perpendicular to the axis of the second wheel (102) and the first central axis; The first central axis is the central axis of the square installation area (2); The motion module further comprises a first drive motor, a second drive motor, a third drive motor and a fourth drive motor for driving the first wheel (101), the second wheel (102), the third wheel (103) and the fourth wheel (104) respectively; The deviation correction module comprises a tracking sensor group (3) and a deviation correction sensor group (4) arranged between the first wheel (101) and the fourth wheel (104); The tracking sensor group (3) comprises a plurality of sensors installed symmetrically to the first central axis, and the deviation correction sensor group (4) comprises a plurality of sensors symmetrically arranged on both sides of the tracking sensor group (3); The control module is connected to the tracking sensor group (3) and the deviation correction sensor group (4) by signals, and is used to control the motion device to start deviation correction when the sensors in the deviation correction sensor group (4) sense the target track, until all the sensors in the tracking sensor group (3) sense the target track; When the sensor in the deviation correction sensor group (4) senses the target track, the motion device is controlled to start deviation correction until all sensors in the tracking sensor group (3) sense the target track, specifically: When a sensor in the deviation correction sensor group (4) senses the target track, the first drive motor is controlled to impart a second speed to the first wheel (101); the direction of the second speed is perpendicular to the first speed and points to the sensor that senses the target track; The range of the value of the second speed is as follows: Wherein, v1 is the first speed, v2 is the second speed, θ is the angle between the line connecting the outermost sensor of the deviation correction sensor group (4) and the center of the square installation area (2) and the first central axis; s is the sensor spacing; and t is the detection interval time of the sensor; When all sensors in the tracking sensor group (3) sense the target track, the first drive motor is controlled to stop the first wheel (101) from rotating.

2. The exercise device according to claim 1, characterized in that The first wheel (101), the second wheel (102), the third wheel (103) and the fourth wheel (104) are all Furley wheels.

3. The exercise device according to claim 2, characterized in that: The target track is a target track with a constant width.

4. The exercise device according to claim 3, characterized in that: The width of the tracking sensor group (3) is the distance between the leftmost sensor and the rightmost sensor, and the width of the tracking sensor group (3) is equal to or slightly larger than the width of the target track.

5. The exercise device according to claim 4, characterized in that: The tracking sensor group (3) comprises two tracking sensors.

6. The sports device according to any one of claims 1 to 5, characterized in that: The motion device further comprises an obstacle avoidance module, which is arranged at the front end of the motion device and is used to sense whether there is an obstacle in front of the motion device; The control device is connected to the obstacle avoidance module signal, and is used to control the motion device to avoid the obstacle when the obstacle avoidance module senses that there is an obstacle in front.

7. The exercise device according to claim 6, characterized in that When the obstacle avoidance module senses that there is an obstacle ahead, controlling the motion device to avoid the obstacle includes the following steps: S1. When the obstacle avoidance module senses that there is an obstacle ahead, the third drive motor and the fourth drive motor are controlled to stop the third wheel (103) and the fourth wheel (104) from rotating; S2. Controlling the first drive motor and the second drive motor to rotate the first wheel (101) and the second wheel (102) so that the motion device moves at a third speed in a preset direction perpendicular to the target trajectory; S3. When the obstacle avoidance module senses no obstacle ahead, the first drive motor and the second drive motor are controlled to stop the first wheel (101) and the second wheel (102) from rotating, and after a preset time, the first drive motor and the second drive motor are controlled to rotate the first wheel (101) and the second wheel (102) so that the motion device moves in a direction opposite to the preset direction at a third speed until the motion device returns to the target track; S4. Control the first drive motor and the second drive motor to stop the first wheel (101) and the second wheel (102) from rotating, and then control the third drive motor and the fourth drive motor to rotate the third wheel (103) and the fourth wheel (104), so that the motion device continues to move forward along the target trajectory at the first speed.

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