Moving speed measurement device

Abstract

To measure a movement speed from the revolution of a roller with high accuracy, without lowering durability.SOLUTION: The present invention comprises: an acceleration detection unit (120) for detecting the acceleration of orthogonal two axes and attached to the rotating region of a roller (110) to be measured; and a computation unit (140) for finding a movement speed from the detection result of the acceleration detection unit (120). The acceleration detection unit (120) allocates the radial and circumferential directions of the roller (110) to the two axes and detects radial and circumferential accelerations. The computation unit (140) calculates the rotation angle of the roller from the radial and circumferential accelerations, differentiates the rotation angle to calculate an angular speed, and calculates the movement speed of the roller (110) from the diameter and angular speed of the roller (110).SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to a moving speed measurement device, and more particularly to a moving speed measurement device that measures the moving speed of a roller from the rotation of the roller.

Background Art

[0002] When measuring the moving speed based on the rotation of various rollers, there is a method of pressing a small measuring wheel against the roller to be measured and measuring the rotation of the rotation axis of the measuring wheel by an encoder. For example, when measuring the moving speed of a compaction machine having a vibrating roller used for embankment compaction construction, the rotation of the rotation axis of the measuring wheel pressed against the vibrating roller can be measured by an encoder.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The measuring wheel is configured to be pressed against the vibrating roller with a strong force and to maintain constant contact with the vibrating roller to perform accurate measurement without error. On the other hand, if the force pressing the measuring wheel against the vibrating roller is weak, the contact between the vibrating roller and the measuring wheel will temporarily separate, resulting in an error in the measurement. Therefore, increasing the force pressing the measuring wheel against the vibrating roller can enable error-free measurement, but on the other hand, there is a problem of reducing the durability of the measuring wheel.

[0005] In the case of the compaction machine having a vibrating roller described in Patent Document 1, it has been proposed to detect the protrusions provided on the vibrating roller by a proximity sensor and detect the moving speed from the rotation of the vibrating roller. In this case, the distance between the proximity sensor and a protrusion on the vibrating roller may change due to the vibration of the vibrating roller. If the protrusion moves further away than the proximity sensor's detection capability allows, a problem arises where the rotation speed of the vibrating roller cannot be accurately detected.

[0006] Although the above explanation uses a vibratory roller as a specific example, similar problems can occur when detecting the rotation of other rollers, for example, due to unevenness in the running surface. Therefore, it is desirable to be able to measure the rotation of the rollers with high accuracy without compromising durability. The present invention aims to provide a speed measuring device that can measure the speed of a roller from its rotation with high accuracy without reducing its durability. [Means for solving the problem]

[0007] (1) The moving speed measuring device according to the present invention is attached to the rotating part of the roller to be measured and comprises an acceleration detection unit that detects acceleration in two orthogonal axes and a calculation unit that determines the moving speed from the detection result of the acceleration detection unit. The acceleration detection unit assigns the radial direction and circumferential direction of the roller to the two axes and detects the radial acceleration and circumferential acceleration. The calculation unit calculates the rotation angle of the roller from the radial acceleration and circumferential acceleration, calculates the angular velocity by differentiating the rotation angle, and calculates the moving speed of the roller from the diameter of the roller and the angular velocity.

[0008] (2) In the moving speed measuring device according to the present invention, the calculation unit uses atan2, which is an arctangent that takes two arguments, to calculate the rotation angle θ as θ = atan2(-α1,-α2). [Effects of the Invention]

[0009] According to the present invention, the speed measuring device for moving speeds calculates the rotation angle of a roller from the radial acceleration and circumferential acceleration of the roller detected by a two-axis acceleration detection unit. This makes it possible to measure the speed of moving speed from the rotation of the roller with high accuracy without reducing durability. [Brief explanation of the drawing]

[0010] [Figure 1] This is a configuration diagram showing the configuration of the moving speed measuring device according to Embodiment 1. [Figure 2] This is an explanatory diagram showing the mounting state of the acceleration detection unit in the moving speed measuring device according to Embodiment 1. [Figure 3] This is an explanatory diagram showing the rotational state of the roller and acceleration detection unit in the moving speed measuring device according to Embodiment 1. [Figure 4] This is an explanatory diagram showing the changes in radial acceleration and circumferential acceleration associated with the rotation of a roller in a moving speed measuring device according to Embodiment 1. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the moving speed measuring device of the present invention will be described with reference to the drawings. In each figure, the same parts are denoted by the same reference numerals.

[0012] Embodiment 1. First, the moving speed measuring device 100 in Embodiment 1 will be described with reference to Figures 1 and 2. Here, the case in which the moving speed measuring device 100 is applied to a vibrating roller will be described as a specific example.

[0013] Figure 1 is a configuration diagram showing the configuration of the moving speed measuring device 100 according to Embodiment 1. Figure 2 is an explanatory diagram showing the mounting state of the acceleration detection unit 120 in the moving speed measuring device 100 according to Embodiment 1.

[0014] [Configuration of the speed measuring device 100] The moving speed measuring device 100 mainly comprises an acceleration detection unit 120, a receiving unit 130, a calculation unit 140, a storage unit 145, a control unit 150, and a vibration generator 160. The moving speed measuring device 100 is installed on a vehicle such as a compaction machine having a vibratory roller.

[0015] The acceleration detection unit 120 includes an acceleration sensor 121 and a transmission unit 122. The acceleration sensor 121 is capable of detecting accelerations in two orthogonal axes. Specifically, the acceleration sensor 121 detects the acceleration in the radial direction of the roller 110 and the acceleration in the circumferential direction of the roller 110. Here, the direction along the axis of the roller 110 is defined as the axial direction, the direction along the radius of the roller 110 is defined as the radial direction, and the direction along the rotation direction of the roller 110 is defined as the circumferential direction. The transmission unit 122 transmits the detection result of the acceleration sensor 121 toward the reception unit 130 installed near the roller 110.

[0016] The reception unit 130 receives the detection result of the acceleration sensor 121 transmitted from the transmission unit 122 of the acceleration detection unit 120 at any part of the vehicle having the roller 110, and extracts the acceleration in the radial direction and the acceleration in the circumferential direction of the roller 110. The transmission unit 122 and the reception unit 130 are configured to be communicable by various wireless communications or optical communications. Note that the connection between the transmission unit 122 and the reception unit 130 is not limited to wireless communication or optical communication, and it is also possible to connect them by wire using a slip ring or the like.

[0017] The calculation unit 140 calculates the rotation angle θ of the roller 110 from the acceleration in the radial direction and the acceleration in the circumferential direction of the roller 110. The storage unit 145 stores various parameters such as the diameter D of the roller 110. The calculation unit 140 differentiates the rotation angle θ to calculate the angular velocity ω = dθ / dt, and calculates the moving speed V of the roller 110 as V = (Dπω) / 360 from the diameter D of the roller stored in the storage unit 145 and the angular velocity ω calculated by differentiation.

[0018] The control unit 150 gives an oscillation control signal for generating vibration with an amplitude corresponding to the calculated moving speed of the roller 110 to the oscillation unit 160. The oscillation unit 160 generates vertical vibration based on the oscillation control signal from the control unit 150 and applies the generated vibration to the roller 110.

[0019] As shown in FIG. 2, the roller 110 to be measured includes a rotating shaft 111, a wheel portion 112, and an outer ring portion 113. The rotating shaft 111 is rotatably supported on a vehicle or the like via a bearing or the like not shown. The wheel portion 112 holds the outer ring portion 113 so as to be centered on the rotating shaft 111. The outer ring portion 113 is firmly configured while maintaining a smooth surface so that vibration can be applied to the road surface as a vibrating roller.

[0020] When the roller 110 is a vibrating roller provided in a self-propelled compactor, a rotational force from an engine of a vehicle not shown and a vertical vibration from the vibration generating unit 160 are applied to the roller 110 through the rotating shaft 111. When the roller 110 is a vibrating roller provided in a hand-pushed compactor, a pressing force in the traveling direction from the hand-pushing portion and a vertical vibration from the vibration generating unit 160 are applied to the rotating shaft 111.

[0021] The acceleration detection unit 120 is attached to the inner surface of the outer ring portion 113 of the roller 110 via the attachment portion 125. When the outer ring portion 113 is a magnetic body containing iron or the like, the attachment portion is constituted by a magnet. The attachment portion 125 may also be an adhesive, a holder provided inside the outer ring portion 113, or the like. The acceleration detection unit 120 detects a radial acceleration α1 with the radial direction of the roller 110 as the first detection axis A_{1}, and detects a circumferential acceleration α2 with the circumferential direction of the roller 110 as the second detection axis A_{2}.

[0022] [Relationship between Rotation of Roller and Acceleration Detection] The state of acceleration detection by the acceleration detection unit 120 accompanying the rotation of the roller 110 will be described with reference to FIG. 3. FIG. 3 is an explanatory view showing the rotation states of the roller 110 and the acceleration detection unit 120 in the moving speed measurement device 100 according to the first embodiment.

[0023] Figures 3(a) to (e) show the orientation and state of the acceleration detection unit 120 in conjunction with the 90° rotation of the counterclockwise rotating roller 110. It is assumed that the roller 110 rotates at a nearly constant rotation angle θ.

[0024] In Figure 3(a), the acceleration detection unit 120 detects a gravitational acceleration of 1G as the radial acceleration α1 on the first radial detection axis A1. The acceleration detection unit 120 detects a circumferential acceleration α2=0 on the second circumferential detection axis A2.

[0025] In Figure 3(b), the acceleration detection unit 120 detects a radial acceleration α1=0 on the first radial detection axis A1. The acceleration detection unit 120 detects a gravitational acceleration of 1G on the second circumferential detection axis A2.

[0026] In Figure 3(c), the acceleration detection unit 120 detects the acceleration due to gravity of -1G as the radial acceleration α1 on the first radial detection axis A1. The acceleration detection unit 120 detects the circumferential acceleration α2=0 on the second circumferential detection axis A2.

[0027] In Figure 3(d), the acceleration detection unit 120 detects a radial acceleration α1=0 on the first radial detection axis A1. The acceleration detection unit 120 detects a gravitational acceleration of -1G on the second circumferential detection axis A2.

[0028] In Figure 3(e), the acceleration detection unit 120 detects a gravitational acceleration of 1G as the radial acceleration α1 on the first radial detection axis A1. The acceleration detection unit 120 detects a circumferential acceleration α2=0 on the second circumferential detection axis A2.

[0029] [Relationship between detected acceleration and rotation angle] Figure 4 shows a graph illustrating the relationship between the radial acceleration α1 and circumferential acceleration α2 = 0 detected by the acceleration detection unit 120 and the rotation of the roller 110. Figure 4 is an explanatory diagram showing the changes in radial acceleration α1 and circumferential acceleration α2 accompanying the rotation of the roller 110 in the moving speed measuring device 100 according to Embodiment 1.

[0030] Figure 3 only shows states (a) to (e) at 90° intervals, but by precisely detecting the radial acceleration α1 and circumferential acceleration α2 for each rotation angle θ, waveforms like those in Figure 4 can be obtained. In Figure 4, the radial acceleration α1 shows a cosθ waveform, and the circumferential acceleration α2 shows a sinθ waveform.

[0031] Furthermore, vertical vibrations applied from the vibrating unit 160 to the roller 110 may cause fine irregularities in the waveform shown in Figure 4. Such fine irregularities can be removed by waveform shaping using a low-pass filter or the like. Therefore, the calculation unit 140 can calculate the rotation angle θ of the roller 110 using the ratio of the radial acceleration α1 to the circumferential acceleration α2. In other words, the calculation unit 140 can calculate the rotation angle θ using atan2, which is an arctangent that takes two arguments, radial acceleration α1 and circumferential acceleration α2, as θ = atan2(-α1,-α2).

[0032] Compared to the conventional method of pressing a measuring wheel against a roller, in Embodiment 1, the acceleration detection unit 120 is fixed to the roller 110, eliminating the need for mechanically moving parts. Therefore, the rotation of the roller 110 can be measured with high accuracy without reducing durability. Compared to the case in Patent Document 1 where a proximity sensor detects the protrusions on the roller, in Embodiment 1, acceleration is measured by an acceleration detection unit 120 fixed to the roller 110. Therefore, it is not affected by changes in distance to the target, and thus the rotation of the roller 110 can be measured with high accuracy without reducing durability.

[0033] [Other embodiments] In Embodiment 1, the case in which the moving speed measuring device 100 is applied to a compaction machine having a vibratory roller is described as a specific example, but it is also possible to detect the rotation of rollers other than the vibratory roller using the moving speed measuring device 100. For example, the speed measuring device 100 of Embodiment 1 can be applied to applications such as measuring the movement speed of various construction machines other than compaction machines, or as a roller distance meter for measuring distance inside a pipeline.

[0034] [Effects obtained by the embodiment] As described above, the following effects can be obtained with the moving speed measuring device 100 of Embodiment 1 of the present invention.

[0035] The first embodiment of the moving speed measuring device 100 includes an acceleration detection unit 120 attached to the rotating part of the roller 110 to be measured and detecting accelerations on two orthogonal axes, and a calculation unit 140 that calculates the moving speed V from the detection results of the acceleration detection unit 120. The acceleration detection unit 120 assigns the radial and circumferential directions of the roller to the two axes and detects the radial acceleration α1 and the circumferential acceleration α2. The calculation unit 140 calculates the rotation angle θ of the roller 110 from the radial acceleration α1 and the circumferential acceleration α2, calculates the angular velocity ω by differentiating the rotation angle θ, and calculates the moving speed V of the roller 110 as V = (Dπω) / 360 from the diameter D of the roller 110 and the angular velocity ω.

[0036] According to this speed measuring device 100, the rotation angle θ of the roller is calculated from the radial acceleration α1 and circumferential acceleration α2 of the roller detected by the acceleration detection unit 120 which detects acceleration in two orthogonal axes. This eliminates the need to use mechanically moving parts or proximity sensors that are affected by distance, and makes it possible to measure the speed V from the rotation of the roller with high accuracy without reducing durability.

[0037] In the first embodiment of the moving speed measuring device 100, the calculation unit 140 calculates the rotation angle θ using atan2, which is an arctangent that takes two arguments, where α1 is the radial acceleration, α2 is the circumferential acceleration, and θ is the rotation angle, by setting θ = atan2(-α1,-α2). This allows the rotation angle θ to be determined with high accuracy, and enables the rapid measurement of the moving speed V from the rotation of the roller with high accuracy. [Industrial applicability]

[0038] The present invention provides a speed measuring device 100 for measuring the speed of various construction machines, such as compaction machines with vibratory rollers, and for use as a roller distance meter for measuring distances within pipelines. It does not require the use of mechanically moving parts or proximity sensors, and measures the speed V from the rotation of the roller with high accuracy without reducing durability, making it suitable for applications requiring high reliability. [Explanation of Symbols]

[0039] 100 Moving speed measuring device, 110 Roller, 111 Rotating shaft, 112 Wheel section, 113 Outer ring section, 120 Acceleration detection section, 121 Acceleration sensor, 122 Transmitter, 125 Mounting section, 130 Receiver, 140 Calculation section, 145 Memory section, 150 Control section, 160 Vibration generator, A1 First detection axis in the radial direction, A2 Second detection axis in the circumferential direction.

Claims

1. An acceleration detection unit (120) attached to a rotating portion of the roller (110) to be measured, which detects acceleration in two orthogonal axes; a calculation unit (140) for calculating a moving speed from the detection result of the acceleration detection unit (120), The acceleration detection unit (120) assigns the radial direction and the circumferential direction of the roller (110) to the two axes, and detects a radial acceleration α1 and a circumferential acceleration α2, The calculation unit (140) calculating a rotation angle θ of the roller from the radial acceleration α1 and the circumferential acceleration α2; The rotation angle θ is differentiated to calculate an angular velocity ω; Calculating the moving velocity V of the roller (110) from the diameter D of the roller (110) and the angular velocity ω; Travel speed measurement device.

2. The calculation unit (140) calculates the rotation angle θ as θ=atan2(−α1, −α2) using atan2, which is an arctangent that takes two arguments. The moving speed measuring device according to claim 1 .

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