AU2021104190A4

AU2021104190A4 - Method for measuring the diameter of single tree based on angle change

Info

Publication number: AU2021104190A4
Application number: AU2021104190A
Authority: AU
Inventors: Yan Chen; Dongpu Fan; Xinwen YU; Xu Zhang
Original assignee: Institute Of Forest Resource Information Techniques Chinese Academy Of Forestry
Current assignee: Institute Of Forest Resource Information Techniques Chinese Academy Of Forestry
Priority date: 2021-07-15
Filing date: 2021-07-15
Publication date: 2021-08-26
Anticipated expiration: 2029-07-15

Abstract

The invention discloses a method for measuring the diameter of a single tree based on angle change, which comprises the following steps: a device adopted by the method wraps the measured trunk around with a sheath steel wire in stretching direction; And when the tree grows, the diameter of the trunk becomes larger, the sheath steel wire is driven to stretch along the stretching direction, thereby driving the shaft rotating to wind the sheath steel wire around the shaft, and the angle sensor can sense the rotating angle of the shaft. The increasing value of the trunk circumference can be calculated according to the rotating angle a and the radius R of the rotating shaft, namely Al R - a . The invention provides reasonable structural design which is simple and reliable to apply, and can utilize the sheath steel wire wrap around the trunk to pull the shaft and the magnet on top of the shaft rotating, the angle sensor on the circuit can sense the rotating angle, and caculate the change of trunk circumference after sensing the angle change, so as to indirectly measure the diameter of the trunk. 1/2 FIGURES 7A power management akln real-time dock battery 5 i nsingle chip sensornucrmemorye 8 6 10 stretch 3 direction Figure 1

Description

1/2

FIGURES

7A power management akln real-time dock battery

5

i nsingle chip sensornucrmemorye

8 6

10 stretch 3 direction

Figure 1

Method for measuring the diameter of single tree based on angle change

TECHNICAL FIELD

The invention relates to the technical field of measuring devices based on angle position

sensing, in particular to a single tree diameter measuring method based on angle change.

BACKGROUND

At present, the common tools for measuring diameter are wheel ruler, measuring ruler

and laser calliper;

(1) Wheel ruler: also called calliper, which is made of wood and aluminium. It consists of

fixed arm, movable arm and ruler body. During diameter measurement, the fixed arm and

the movable arm clip the trunk, and the ruler shows the measuring result . Its

shortcomings are: the movable arm is too tight in contact with the ruler body, which

makes it difficult to move; If it is too loose in contact with the ruler body, it often leads to

non-parallel with the fixed arm, which leads to inaccurate measurement, and is greatly

affected by humidity and weather, which makes it inconvenient to carry (the movable

arm is easy to fall off).

(2) Diameter tape measure: it is also called measuring ruler, which includes cloth

measuring ruler, steel measuring ruler and bamboo measuring ruler. The circumference

and the diameter reading corresponding to the circumference are printed up and down on

one side of the diameter tape. During measurement, the ruler should be tightened around

the trunk, and both hands of the measuring person will inevitably contact with the trunk.

The wrapping tightness of the tape is affected by the forms of the trunk surface, barks, the

stretching force, etc. Even different measuring person may also affect the measuring

result.

(3)CCD calliper and laser scanning calliper, both are diameter measuring instruments

based on optical geometry principle. Put the linear CCD in a parallel light path, the

measured object is placed in the light path in front of the CCD, so the light emitted to the

CCD is partially blocked by the object. Therefore, the output signal of the CCD has a

notch, and the diameter of the measured object is obtained by the corresponding

relationship between the width of the notch and the size of the object. When measuring a

large tree, the CCD needs to be in large size, and a large-sized CCD is particularly

expensive.

Laser scanning measurement: the object placed in the measuring area is scanned at high

speed, and the light projected on the photoelectric receiver is blocked when the optical

beam scans the object. By analysing the output signal of the photoelectric receiver, the

diameter of the object can be calculated.

These two kinds of optical device have complex structures, limited measuring diameter

range, high requirements for the working environment of the measured object, and are of

high cost, inconvenient to carry and not easy to operate for measuring. They are not

suitable for applications in complex and changeable forest environments in large-scale

forest areas, mountainous area.

To sum up, the invention proposes a single tree diameter measurement method based on

angle change, which can effectively measure the single tree diameter change.

SUMMARY

Aiming at overcoming the defects in the previous work, this invention provides a single

tree diameter measurement method based on angle change. The invention provides

reasonable structural design which is simple and reliable to apply and can utilize the sheath steel wire wrap around the trunk to pull the shaft and the magnet on top of the shaft rotating and the angle sensor on the circuit can sense the rotating angle and then calculate the change of trunk circumference based on the angle change, so as to indirectly measure the diameter of the trunk.

In order to achieve the purpose above, the present invention is realized by the following

technical scheme: a method for measuring the diameter of a single tree based on angle

change is as follows: the device adopted by the method wraps the trunk around with a

sheath steel wire in stretching direction; And when the tree grows, the diameter of the

trunk becomes larger, the sheath steel wire is driven to stretch along the stretching

direction, thereby driving the shaft rotating to wind the sheath steel wire around the shaft,

and the angle sensor can sense the rotating angle of the shaft. The increasing value of the

trunk circumference can be calculated according to the rotating angle a and the radius R

of the rotating shaft, namely

Al = R - a.

The method has the following beneficial effects that the diameter change of the trunk can

be better measured by utilizing the sheath steel wire wrapping around the trunk to pull the

shaft of the angle sensor to rotate, the angle sensor can sense the rotating angle change,

and then calculate the change of trunk circumference based on the angle change, so as to

indirectly measure the diameter of the trunk with high precision and satisfying results.

BRIEF DESCRIPTION OF THE FIGURES

The following describes the invention in detail with reference to the figures and specific

embodiments.

Fig. 1 is a schematic structural diagram of the present invention;

Fig. 2 is a schematic diagram of the structure and position relationship of the sensor for

measuring the diameter of a single tree according to the present invention.

DESCRIPTION OF THE INVENTION

In order to make the technical means, creative features, goals and effects of the present

invention easy to understand, the present invention will be further explained with specific

embodiments.

With reference to Fig. 1-2, the specific embodiment adopts the following technical

scheme: a single tree diameter measuring device based on angle change comprises a

circuit board 13, a rotating shaft 11 and a sheath steel wire 10, wherein the circuit board

13 is equipped with a single chip microcomputer 1, an alkaline battery 2, a reset circuit 3,

a real-time clock 4, a memory 5, a serial interface 6, a power management module 7, an

angle sensor 8 and a tension motor 9, and one end of the sheath steel wire 10 winds

around the rotating shaft 11 and the other end of the sheath steel wire winds around the

trunk. The rotating shaft 11 is connected with the tension motor 9. The upper end of the

rotating shaft 11 is mounted with a permanent magnet 12, an angle sensor 8 fixed on the

circuit board 13. The angle sensor 8 is also connected with a power management module

7 and a single chip microcomputer 1, which is also connected with the tension motor 9.

The power management module 7 is also connected with the single chip microcomputer 1

through an alkaline battery 2. The single chip microcomputer 1 connects with the reset

circuit 3, real time clock 4, the memory 5, the serial interface 6 respectively. The single

chip microcomputer 1 adopts the model of STM32L476RBT6. The angle sensor 8 adopts

a 14-bit magnetic angle sensor AS5048A. The model of the real time clock 4 is DS3231.

The tension motor 9 adopts A 03400. The angle sensor 8 adopts a sensor power supply

TPS61016DGSR.

A method for measuring the diameter of a single tree based on angle change is as follows:

the device adopted by the method wraps the measured trunk around with a sheath steel

wire in stretching direction; And when the tree grows, the diameter of the trunk becomes

larger, the sheath steel wire is driven to stretch along the stretching direction, thereby

driving the shaft rotating to wind the sheath steel wire around the shaft, and the angle

sensor can sense the rotating angle of the shaft. The increasing value of the trunk

circumference can be calculated according to the rotating angle a and the radius R of the

rotating shaft, namely

Al = R - a.

The angle sensor of this embodiment adopts a 14-bit high-precision magnetic angle

sensor, which directly measures the rotating angle of the rotating shaft by sensing the

magnetic field angle of the permanent magnet attached to the upper end of the rotating

shaft. Compared with other diameter instruments, this design is very simple in structure

, not only avoids complex mechanical structure for converting the rotation angle into linear

displacement, but also avoids the measurement error caused by the gap of gear rack and

other mechanisms.

The angle sensor measures the relative angle change, which is basically unaffected by the

temperature fluctuation. In addition, the angle sensor used in this scheme is usually

applied in automobiles, which has the function of temperature compensation inside, and

can work normally in the temperature range of -40°C-150°C, with the constant precision

guaranteed.

Embodiment 1: the circumference measurement accuracy can be calculated according to

the measurement accuracy of the angle sensor. In this embodiment, a sheath steel wire

with a diameter of 2mm winding around a rotating shaft with a diameter of 25mm is used,

and a 14-bit high-precision magnetic angle sensor is adopted. The minimum measuring

resolution for the change of trunk circumference is 5 P m.

The above introduction shows and describes the basic measuring principle and main

features of the invention, as well as the advantages of the present invention. It will be

understood by those skilled in this field that the present invention is not limited by the

above embodiments. The embodiments above and descriptions only illustrate the

principle of the present invention. Without departing from the spirit and scope of the

present invention, there will be various modifications and improvements in the present

invention, all of which fall within the scope of the claimed invention. The extent scope of

the present invention is defined by the appended claims and their equivalents.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method for measuring the diameter of a single tree based on angle change,

characterized in that the device adopted by the method comprises a circuit board, a

rotating shaft and a steel wire sheath, wherein the circuit board is equipped with a single

chip microcomputer, an alkaline battery, a reset circuit, a real-time clock, a memory, a

serial interface, a power management module, an angle sensor and a tension motor; One

end of the sheath steel wire winds on the rotating shaft, and the other end winds around

the trunk to be measured, and the rotating shaft is connected with the tension motor; A

permanent magnet is arranged at one end of the rotating shaft; An angle sensor is

arranged above the permanent magnet and fixed on the circuit board, and the angle sensor

is also connected with a power management module and a single chip microcomputer;

The single chip microcomputer is also connected with a tension motor; The power

management module is also connected with the single chip microcomputer through an

alkaline battery, and the single chip microcomputer is respectively connected with a reset

circuit, a real-time clock, a memory and a serial interface;

The angle sensor adopts a 14-bit high-precision magnetic angle sensor, which directly

measures the rotation angle of the rotating shaft by sensing the magnetic field angle of the

permanent magnet attached to the upper end of rotating shaft. The high-precision

magnetic angle sensor has a function of temperature compensation inside and can work

normally within the temperature range of-40-150°C,with the constant precision

guaranteed;

The measuring method is as follows: the device adopted by the method wraps the

measured trunk around with sheath steel wire in stretching direction; And when the tree grows, the diameter of the trunk becomes larger, the sheath steel wire is driven to stretch along the stretching direction, thereby driving the shaft rotating to wind the sheath steel around the shaft, and the angle sensor can sense the rotating angle of the shaft; The increasing value of the trunk circumference can be calculated according to the rotating angle a and the radius R of the rotating shaft, namely Al = R - a.

FIGURES 1/2

Figure 1