A portable method and device for measuring the deflection angle of guide wheels of wheeled tractors

Abstract

The invention discloses a portable method and device for measuring the deflection angle of a guide wheel of a wheeled tractor. The bottom end of an angle sensor is fixedly connected to the center of an upper surface of a base, the top end of the angle sensor is fixedly connected to the center of an upper cover, the central axis of the angle sensor is colinear with the central axes of the base and the upper cover, a left limit plate and a right limit plate are fixedly arranged on the upper surface of the upper cover and are symmetrically arranged relative to the center of the upper cover, four track wheels evenly arranged along the center of the base are connected below the base, a track is matched below every two track wheels, and the track is laid along the sliding track of the steering center of the tractor guide wheel; the guide wheel of the tractor to be measured is parked at the center position of the upper cover, the axial sides of the guide wheel are clamped with a left limit plate and a right limit plate, the steering wheel of the tractor is rotated, the upper cover is driven to rotate by the deflected guide wheel, and then the angle sensor is driven to rotate to output an angle signal, so as to accurately measure the turning angle of the guide wheel of the wheeled tractor, and the device can move with the movement of the rotation center of the guide wheel.

Description

Technical Field

[0001] The present invention relates to the field of vehicle automatic driving control systems, in particular to automatic driving control of wheeled tractors in agricultural machinery, and specifically to a device and method for measuring the deflection angle of a guide wheel of a wheeled tractor. Background Art

[0002] In recent years, intelligent agricultural equipment has developed rapidly, and agricultural machinery automatic driving technology has made breakthrough progress. The dynamic response relationship between the steering wheel angle and the guide wheel angle is one of the control parameters of tractor automatic driving. If the relationship between the steering wheel angle and the guide wheel angle is measured directly on the ground, the ground friction resistance will affect the accuracy of the measurement, so it is necessary to eliminate interference factors such as ground resistance. The existing measurement method is mainly to draw lines on the ground and measure with an angle ruler, which has a large error.

[0003] The document with Chinese patent publication number CN107478188A discloses a measuring instrument for measuring the turning angle of automobile wheels, which measures the turning angle of the wheel by fixing a turning plate base on the ground, placing a turning plate cover on the top, and placing an angle sensor between the turning plate base and the cover. If this measuring instrument is used to measure the deflection angle of the tractor guide wheel, a large error will be generated, because: the upper end of the guide wheel of the wheeled tractor tilts outward at an angle, called the camber angle, the front end is retracted inward at an angle, called the toe angle, and the steering knuckle vertical axis also tilts inward and backward at an angle, respectively called the inclination angle and the caster angle. Due to the above angle problems, when the tractor turns in situ, the guide wheel will slip and slide, that is, the center of the guide wheel steering will change with the rotation of the guide wheel, and the steering center trajectory of the guide wheel is a regular curve. Therefore, the turning plate base fixed on the ground is not suitable for measuring the deflection angle of the tractor guide wheel that will slip and slide. Summary of the invention

[0004] The purpose of the present invention is to address the above problems existing in the measurement of the guide wheel deflection angle of the tractor, and to provide a portable guide wheel deflection angle measuring device which can move autonomously with the steering center of the guide wheel, is simple to operate, and has accurate measurement, as well as a measuring method for the measuring device.

[0005] The present invention discloses a portable device for measuring the deflection angle of a guide wheel of a wheeled tractor, which adopts the following technical scheme: the device comprises a base, an upper cover and an angle sensor, wherein the upper cover is located above the base, the center of the upper surface of the base is fixedly connected to the bottom end of the angle sensor, the top end of the angle sensor is fixedly connected to the center of the upper cover, the central axis of the angle sensor is colinear with the central axes of the base and the upper cover, a left limit plate and a right limit plate which are symmetrically arranged relative to the center of the upper cover are fixedly arranged on the upper surface of the upper cover, four track wheels which are evenly arranged along the center of the base are connected below the base, a track is matched below every two track wheels, the track wheels can roll on the track, and the track is laid along the sliding track of the steering center of the tractor guide wheel.

[0006] Furthermore, a lower washer is fixedly embedded on the upper surface of the base, and an upper washer is fixedly embedded on the lower surface of the upper cover. The upper washer and the lower washer have the same structure and are both annular. A annular plane retaining frame is provided between the upper washer and the lower washer. Through holes with the same number and corresponding structure as the steel balls are evenly opened on the annular surface of the plane retaining frame in the circumferential direction. A steel ball is placed in each through hole. The upper and lower heights of the plane retaining frame are smaller than the outer diameter of the steel ball. Grooves corresponding to the steel balls are provided on the lower surface of the upper washer and the upper surface of the lower washer. The grooves of the upper washer and the lower washer are buckled on the steel ball. The central axes of the upper cover, the upper washer, the lower washer and the plane retaining frame are collinear.

[0007] The measuring method of the portable wheel tractor guide wheel deflection angle measuring device of the present invention adopts the following technical scheme: the guide wheel of the tractor to be measured is parked at the center position of the upper cover, the left limit plate and the right limit plate are used to clamp the axial two sides of the guide wheel, the tractor steering wheel is turned, the tractor guide wheel is turned, and the upper cover is driven to rotate synchronously, the base moves freely along the track with the track wheel, and the angle sensor measures the rotation angle of the guide wheel.

[0008] Furthermore, taking the speed of the tractor wheels as input, find the coordinate change of each wheel contact point over time in the coordinate system, list the coordinate change equation of each contact point, draw the running trajectory of the tractor guide wheel, obtain the motion trajectory of the guide wheel when the tractor turns on the spot, and process the track according to this motion trajectory.

[0009] The above technical solution of the present invention has the following advantages:

[0010] 1. The measuring device of the present invention drives the upper cover to rotate by deflecting the guide wheel, thereby driving the angle sensor to rotate and output an angle signal, accurately measuring the steering angle of the guide wheel of the wheeled tractor, and receiving the signal of the angle sensor to obtain the steering angle of the guide wheel.

[0011] 2. The present invention is adaptive to the inclination angle of the tractor front wheel and the vertical shaft, and the device can move with the movement of the rotation center of the guide wheel. The device is small in size and weight and is easy to carry to the test site.

[0012] 3. The present invention is simple to operate, small in size, applicable to a variety of tractors, and low in cost.

[0013] 4. The turning angle signal in the present invention can be monitored and collected in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are used to illustrate the present invention but cannot be used to limit the scope of the present invention.

[0015] Figure 1 It is an isometric view of a portable device for measuring the deflection angle of a guide wheel of a wheeled tractor according to the present invention;

[0016] Figure 2 for Figure 1 The main structural section view;

[0017] Figure 3 for Figure 1 Structural diagram of the middle upper cover 2b;

[0018] Figure 4 for Figure 2 Axonometric view of the assembly structure of the middle base 2a and the angle sensor assembly 1;

[0019] Figure 5 for Figure 4 A top view of the middle base 2a;

[0020] Figure 6 for Figure 1 Structural diagram of the left limit plate 4c and the right limit plate 4d;

[0021] Figure 7 for Figure 2 A magnified three-dimensional structure diagram of the middle barrier member 3;

[0022] Figure 8 for Figure 2 A magnified three-dimensional structure of the middle track wheel 4a;

[0023] Fig. 9 for Figure 1 Schematic diagram of the measuring state of the guide wheel deflection angle measuring device shown.

[0024] In the figure: 1. Angle sensor assembly; 1a. Angle sensor; 1a-1. Rotating shaft; 1a-2. Flange plate; 1a-3. Transmission line; 1b. Bolt; 2. Support mechanism; 2a. Base; 2a-1. Through hole; 2a-2. Threaded hole; 2a-3. Bolt hole; 2b. Upper cover; 2b-1. Through hole; 2b-2. Through hole; 3. Resistance eliminating part; 3a. Upper washer; 3b. Lower washer; 3c. Steel ball; 3d. Plane retaining frame; 4. Slip compensation assembly; 4a. Track wheel; 4a-1. Bolt hole; 4a-2. Roller seat; 4a-3. Roller shaft; 4a-4. Roller; 4b. Track; 4c. Left limit plate; 4c-1. Waist-shaped hole; 4d. Right limit plate; 4d-1. Waist-shaped hole; 4e. Bolt; 4f. Bolt; A. Guide wheel; B. Deflection angle measuring device. DETAILED DESCRIPTION

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms nesting, insertion, and connection should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or it can be an indirect connection via an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0026] like Figure 1 and Figure 2 As shown, a portable device for measuring the deflection angle of a guide wheel of a wheeled tractor of the present invention comprises an angle sensor assembly 1, a support mechanism 2, a resistance eliminating member 3 and a slip compensation assembly 4; the support mechanism 2 is arranged horizontally, the angle sensor assembly 1 is arranged in the middle of the support mechanism 2, the resistance eliminating member 3 is nested in the support mechanism 2, and the slip compensation assembly 4 is arranged above and below the support mechanism 2. The slip compensation assembly 4 comprises a track wheel 4a, a track 4b, a left limit plate 4c and a right limit plate 4d, the track wheel 4a and the track 4b are installed below the support mechanism 2, and the left limit plate 4c and the right limit plate 4d are installed above the support mechanism 2.

[0027] Combination Figure 3 and Figure 4 As shown, the support mechanism 2 is composed of a base 2a and an upper cover 2b, the upper cover 2b is directly above the base 2a, and both the base 2a and the upper cover 2b are disc-shaped structures with the same central axis. Downward bosses are evenly arranged at the edge of the upper cover 2b, and the bosses are tangent to the edge of the base 2a downward, and are not constrained to each other, so that the upper cover 2b and the base 2a are in contact with each other, which prevents the upper cover 2b from slipping off and limits the position, and leaves a certain height gap between the lower surface of the upper cover 2b and the upper surface of the base 2a.

[0028] Two through holes 2b-1 and 2b-2 are formed on the upper cover 2b and are symmetrical along the center, and are used to connect the left limit plate 4c and the right limit plate 4d in the slip compensation assembly 4 respectively.

[0029] The bottom end of the angle sensor assembly 1 is fixedly connected to the center of the upper surface of the base 2a. The angle sensor assembly 1 consists of an angle sensor 1a and a bolt 1b. The angle sensor 1a is used to measure the rotation angle of the guide wheel. The central axis of the angle sensor 1a is collinear with the central axis of the base 2a and the upper cover 2b. Its top end is fixedly connected to the upper cover 2b, so that the angle sensor 1a is fixedly connected between the base 2a and the upper cover 2b. The angle sensor 1a has a rotating shaft 1a-1, a flange plate 1a-2 and a transmission line 1a-3. When specifically connected, the upper end of the rotating shaft 1a-1 is inserted into the corresponding blind hole of the upper cover 2b, and the central axis of the rotating shaft 1a-1 is collinear with the central axis of the upper cover 2b. A threaded hole is provided on the flange plate 1a-2 coaxially sleeved on the rotating shaft 1a-1, and is fixedly connected to the base 2a by bolts 1b.

[0030] Combination Figure 5 The base 2a has a through hole 2a-1, two symmetrical threaded holes 2a-2 and four groups of bolt holes 2a-3. The flange plate 1a-2 of the angle sensor 1a is connected to the two symmetrical threaded holes 2a-2 by two bolts 1b, and the angle sensor 1a is fixed to the base 2a. The transmission line 1a-3 of the angle sensor 1a is led out through a through hole 2a-1 on the base 2a and connected to an external signal receiving device.

[0031] Combination Figure 1 , Figure 3 and Figure 6 The left limit plate 4c and the right limit plate 4d are fixedly arranged on the upper surface of the upper cover 2b. The left limit plate 4c and the right limit plate 4d are arranged symmetrically with respect to the center of the upper cover 2b. The left limit plate 4c and the right limit plate 4d are both L-shaped plates. The horizontal plates of the left limit plate 4c and the right limit plate 4d are each provided with a waist-shaped hole, and each is connected to the upper cover 2b by a bolt. When specifically connected, the left limit plate 4c has a waist-shaped hole 4c-1, which is fixedly connected by bolts 4e. Figure 3 The through hole 2b-1 of the middle upper cover 2b and the waist-shaped hole 4d-1 on the right limit plate 4d are fixedly connected by bolts 4f Figure 3 The through hole 2b-2 of the upper cover 2b in the middle. The length direction of the waist-shaped hole 4c-1 and the waist-shaped hole 4d-1 is arranged radially, so that the positions of the left limit plate 4c and the right limit plate 4d can be adjusted through the waist-shaped hole 4c-1 and the waist-shaped hole 4d-1 respectively, and the guide wheel is clamped between the vertical plates of the left limit plate 4c and the right limit plate 4d. The distance between the left limit plate 4c and the right limit plate 4d can be adjusted to adapt to and fix guide wheels of different sizes.

[0032] Combination Figure 7As shown, the barrier element 3 is composed of an upper washer 3a, a lower washer 3b, a steel ball 3c and a plane retainer 3d. The lower washer 3b is fixedly embedded in the groove on the upper surface of the base 2a to prevent the lower washer 3b from having relative movement with the base 2a, and is an interference fit with the base 2a. The upper washer 3a is fixedly embedded in the groove on the lower surface of the upper cover 2b, and is also an interference fit with the upper cover 2b, and is fixed together. The upper washer 3a and the lower washer 3b are both annular and have exactly the same structure. Between the upper washer 3a and the lower washer 3b is an annular plane retainer 3d, and the annular surface of the plane retainer 3d is evenly opened with through holes of the same number and corresponding structure as the steel balls 3c in the circumferential direction, and a steel ball 3c is placed in each through hole, so that a number of steel balls 3c are evenly arranged through the plane retainer 3d. The upper and lower heights of the plane retainer 3d are smaller than the outer diameter of the steel ball 3c, so that the steel ball 3c contacts the lower surface of the upper washer 3a and the upper surface of the lower washer 3b. Grooves corresponding to the steel ball 3c are provided on the lower surface of the upper washer 3a and the upper surface of the lower washer 3b. The grooves of the upper washer 3a and the lower washer 3b are buckled on the steel ball 3c, so that the steel ball 3c extends into the groove and can roll in the groove. The steel ball 3c has the function of reducing friction resistance and bearing weight. The plane retainer 3d evenly separates the steel balls 3c from each other, so that each steel ball 3c rolls normally between the upper washer 3a and the lower washer 3b, plays the role of holding and guiding, and can reduce the rotation resistance between the base 2a and the upper cover 2b.

[0033] The central axes of the upper cover 2b, the base 2a, the upper gasket 3a, the lower gasket 3b and the plane holder 3d are collinear. The angle sensor 1a passes through the middle through hole of the upper gasket 3a, the lower gasket 3b and the plane holder 3d. The outer diameter of the angle sensor 1a is much smaller than the inner diameter of the upper gasket 3a, the lower gasket 3b and the plane holder 3d, and no interference occurs.

[0034] Combination Figure 1 and Figure 8As shown, four track wheels 4a are installed below the base 2a, and the four track wheels 4a are evenly arranged along the center of the base 2a, and each track wheel 4a is connected through a group of bolt holes 2a-3 provided on the base 2a. A track 4b is matched below every two track wheels 4a, and the track 4b is an I-shaped track, and the track wheel 4a can roll on the track 4b. Since the guide wheel will slip when the tractor turns in place, the steering center track of the guide wheel is a regular curve. Therefore, the track 4b is laid along the slip track, and when the track wheel 4a moves along the track 4b, it adapts to the constantly changing rotation center of the guide wheel. Each track wheel 4a is composed of a roller 4a-4, a roller shaft 4a-3 and a roller seat 4a-2, and each roller seat 4a-2 is provided with a group of bolt holes 4a-1, and the bolt holes 4a-1 correspond to the positions of a group of bolt holes 2a-3 on the base 2a, and are used to fix the track wheel 4a and the base 2a. The two ends of the roller shaft 4a-3 are connected to the roller seat 4a-2, and the roller 4a-4 is coaxially sleeved in the middle, and the roller 4a-4 is placed on the track 4b and rolls along the track 4b. The track wheel 4a is a single-sided track wheel, and it is relatively simple to install and disassemble.

[0035] Combination Fig. 9 As shown, when the deflection angle measuring device B of the present invention is working, the track 4b is pre-laid, which is the motion track of the guide wheel A when the tractor turns in place. The functional relationship between the wheel coordinates and time is used to study the turning track of the tractor guide wheel A. By establishing a suitable coordinate system, the speed of the wheel is used as the input factor, and the coordinate change of each wheel contact point over time is found in the coordinate system, and then the coordinate change equation of each contact point is listed. Finally, the running track diagram of the tractor guide wheel A is drawn using MATLAB software, and it is concluded that the motion track of the guide wheel A when the tractor turns in place is a regular curve, which is verified by a real vehicle test. According to this curve rule, that is, the motion track, the track 4b is processed, and the track wheel 4a and the base 2a are placed on the track 4b together, so that the deflection angle measuring device B can move autonomously with the rotation of the guide wheel A, ensuring the measurement accuracy.

[0036] The driver parks the guide wheel A of the tractor to be tested at the center of the upper cover 2b, adjusts the fixed positions of the left limit plate 4c and the right limit plate 4d, and clamps the axial sides of the guide wheel A with the left limit plate 4c and the right limit plate 4d respectively to eliminate the error caused by the slipping of the guide wheel A. Then the driver turns the steering wheel, and the tractor guide wheel A drives the upper cover 2b to rotate synchronously when turning, and the rotating shaft 1a-1 of the angle sensor 1a fixedly connected to the center of the upper cover 2b rotates the same angle accordingly, which is then converted into the rotational motion of the rotating shaft 1a-1 of the angle sensor 1a, thereby measuring the rotation angle of the guide wheel, and transmitting the rotation angle value signal to the signal receiving device through the transmission line 1a-3. At the same time, the base 2a moves freely along the track 4b with the track wheel 4a, that is, moves along the slip track of the guide wheel A, so that the guide wheel deflection angle measuring device B automatically adapts to the constantly changing rotation center of the guide wheel A, ensuring the measurement accuracy of the rotation angle of the tractor guide wheel A. During the measurement process, since the rotation resistance of the resistance eliminating member 3 is very small, the actual rotation angle error of the guide wheel A is also small.

[0037] Steering angle scale lines can be added on the periphery of the base 2a to assist in measuring the rotation angle of the guide wheel A.

[0038] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A portable device for measuring the deflection angle of a guide wheel of a wheeled tractor, comprising a base (2a), an upper cover (2b) and an angle sensor (1a), wherein the upper cover (2b) is located above the base (2a), and is characterized in that: The center of the upper surface of the base (2a) is fixedly connected to the bottom end of the angle sensor (1a), the top end of the angle sensor (1a) is fixedly connected to the center of the upper cover (2b), the center axis of the angle sensor (1a) is colinear with the center axes of the base (2a) and the upper cover (2b), the upper surface of the upper cover (2b) is fixedly provided with a left limit plate (4c) and a right limit plate (4d) arranged symmetrically relative to the center of the upper cover (2b), the lower part of the base (2a) is connected to four track wheels (4a) evenly arranged along the center of the base (2a), each two track wheels (4a) are matched with a track (4b) below, the track wheels (4a) can roll on the track (4b), and the track (4b) is laid along the sliding track of the steering center of the tractor guide wheel; the upper surface of the base (2a) is fixedly embedded with a lower gasket (3b), the lower surface of the upper cover (2b) is fixedly embedded with an upper gasket (3a), and the upper gasket (3a) and the lower gasket (3b) have the same structure. , are both annular, and between the upper washer (3a) and the lower washer (3b) is an annular plane retainer (3d), and the annular surface of the plane retainer (3d) is uniformly provided with through holes having the same number and corresponding structure as the steel ball (3c) in the circumferential direction, and a steel ball (3c) is placed in each through hole, and the upper and lower heights of the plane retainer (3d) are smaller than the outer diameter of the steel ball (3c), and the lower surface of the upper washer (3a) and the upper surface of the lower washer (3b) are both provided with corresponding The grooves of the upper washer (3a) and the lower washer (3b) are buckled on the steel ball (3c); the central axes of the upper cover (2b), the upper washer (3a), the lower washer (3b) and the plane retaining frame (3d) are collinear; the base (2a) and the upper cover (2b) are both disc-shaped and have the same central axis; downward bosses are evenly arranged at the edge of the upper cover (2b); the bosses are tangent to the edge of the base (2a) downward and are not constrained to each other.

2. A portable device for measuring the deflection angle of a guide wheel of a wheeled tractor according to claim 1, characterized in that: The angle sensor (1a) comprises a rotating shaft (1a-1), a flange plate (1a-2) and a transmission line (1a-3); the upper end of the rotating shaft (1a-1) is inserted into a corresponding blind hole of an upper cover (2b); the central axis of the rotating shaft (1a-1) is colinear with the central axis of the upper cover (2b); and the flange plate (1a-2) coaxially sleeved on the rotating shaft (1a-1) is fixedly connected to the base (2a) via bolts (1b).

3. A portable wheel tractor guide wheel deflection angle measuring device according to claim 1, characterized in that: The left limit plate (4c) and the right limit plate (4d) are both L-shaped plates. The horizontal plates of the left limit plate (4c) and the right limit plate (4d) are each provided with a waist-shaped hole and are each connected to the upper cover (2b) via a bolt, so that the distance between the left limit plate (4c) and the right limit plate (4d) can be adjusted.

4. A method for measuring the guide wheel deflection angle of a portable wheel tractor according to claim 1, characterized in that: The guide wheel of the tractor to be tested is parked at the center position of the upper cover (2b), and the left limit plate (4c) and the right limit plate (4d) are used to clamp the two axial sides of the guide wheel. The tractor steering wheel is turned, and the tractor guide wheel is turned, driving the upper cover (2b) to rotate synchronously. The base (2a) moves freely along the track (4b) along with the track wheel (4a), and the angle sensor (1a) measures the rotation angle of the guide wheel.

5. The measuring method according to claim 4, characterized in that: Taking the speed of the tractor wheel as input, find the coordinate change of each wheel contact point over time in the coordinate system, list the coordinate change equation of each contact point, draw the running trajectory of the tractor guide wheel, and obtain the motion trajectory of the guide wheel when the tractor turns in place, and process the track (4b) according to this motion trajectory.

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