JP2008002842A - Method and device for measuring attitude of working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for measuring an attitude of a working machine, capable of carrying out easily concrete prework for execution, at low cost, even when carried out in advance or posteriorly. <P>SOLUTION: In the method for measuring the attitude of the swingable working machine 1, inclination sensors S1-S3 as sensors are arranged on a measuring object (boom in Fig.) 11 to be measured of the working machine, to obtain output information from the inclination sensors S1-S3 when swinging the working machine 1, and the attitude including an inclination angle under an operation of the object 11 to be measured is found using the output information from the inclination sensors S1-S3 in the swing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  For example, the present invention relates to a posture measuring method and a measuring device of a work machine such as a hydraulic excavator, a bulldozer, a material handling device of a lifting magnet specification, and the like.

  Patent Document 1 discloses a position measurement system for a traveling construction machine. As shown in FIG. 4, this measurement system includes an excavator 1, angle sensors 21, 22, and 23 that detect the angle of the boom 11, the angle of the arm 12, and the angle of the bucket 13, A tilt sensor 24 for detecting the tilt angle of the main body 3 in the front-rear direction is incorporated, and further, correction data from two GPS antennas 31 and 32, a GPS receiver (not shown), and a reference station are transmitted via the radio antennas 33 and 34. A wireless device (not shown) for receiving and a wireless antenna 35 for transmitting position data are incorporated. A panel computer (not shown) calculates the position of the tip (monitor point) of the bucket 13 of the excavator 1 based on the position data from the GPS receiver and the angle data from the various sensors 21 to 24 described above.

JP 2002-321065A

  However, this position measurement system requires a lot of equipment and sensors including a GPS device in order to measure the basic attitude of the hydraulic excavator 1, and has a problem that the device is complicated and expensive.

  In addition, there is a big problem that the angle sensors 21, 22, 23, etc. must be mounted at predetermined mounting positions. In order to accurately mount the sensor at a predetermined mounting position, a tapped hole or the like must be formed in advance at the mounting position from the design stage. For work machines that do not take this into consideration, it is necessary to have both physical installation technology and appropriate knowledge about the installation position to determine the position to be installed at the site afterwards. In reality, this is not always a simple task. Therefore, there is a problem that it is difficult to apply to existing work machines. In developing automatic control systems, there are few requests to attach an attitude measurement system to existing work machines for simulation for development, such as when collecting a lot of data related to the behavior of many existing types of work machines. Absent. However, the conventional attitude measurement system is actually accompanied by many difficulties in attaching to existing work machines.

  The present invention has been developed in view of such circumstances, and is a low cost and a work machine that can easily perform a specific pre-work for posture measurement in both the pre- and post- cases. It is an object of the present invention to provide a posture measuring method or apparatus.

  The present invention relates to a method for measuring a posture of a work machine capable of turning, a procedure of disposing an inclination sensor as the sensor on a measured object to be measured by the work machine, and the inclination when the work machine is turned. The above-mentioned problem is solved by including a procedure for obtaining sensor output information and a procedure for obtaining a posture including the tilt angle during operation of the measured object using the output information of the tilt sensor during the turning. It is a thing.

  In the present invention, a “tilt sensor” is employed as the sensor for measuring the posture of the work machine during operation. According to the present invention, the posture during operation of the work machine, in particular, the most important tilt angle of the measured object can be measured by “only the tilt sensor”.

  Inclination sensors are conventionally used to measure the “static angle” of the main body or member of a work machine (eg, boom, arm, bucket, etc.), It is not used as a sensor for measuring the tilt angle of a member during operation. This is because the tilt sensor is affected by the centrifugal force applied to the member due to its structure. Therefore, if the tilt sensor is actually applied to posture measurement during operation of the work machine, for example, as disclosed in JP-A-5-319785, the turning angle is detected by a potentiometer, Correction work such as taking into account the moment generated by the centrifugal force of rotation was essential.

  In general, grasping the centrifugal force by turning requires not only a separate sensor such as a potentiometer, but also the centrifugal force cannot be obtained unless the distance from the turning axis (that is, the sensor mounting position) is known. Since the distance changes dynamically, the correction requires a great deal of ingenuity and computer computing power.

  However, in the present invention, the “weakness of being affected by the centrifugal force of the turning” in the tilt sensor is conversely captured, and the centrifugal force generated by the turning of the work body is actively used as “useful information for posture measurement”. I am trying to use it.

  Although a specific measuring method will be described in detail later, in the present invention, by simply attaching a plurality of (in some cases, one) tilt sensors to a measured object (for example, a boom) at an arbitrary position, the rotation of the work body can be performed. The angle (inclination angle) with respect to the direction of gravity of the measurement object can be accurately obtained by removing the influence of the centrifugal force. If the tilt angle of the measured object is required (this is often sufficient), the length of the measured object is known by design, so the tip (monitor point) height, etc. can be easily calculated You can also ask for.

  In the present invention, when there is no known information, what is basically essential is the output information of the three tilt sensors arranged at three points different from the pivot axis and the information of the distance between the three tilt sensors. It is. This is the only input information necessary for measurement.

  As will be described later, when there is some known information or specific conditions, the posture measurement system can be constructed more easily by taking in the known information and conditions.

  In the present invention, the turning angular velocity of the main body of the work machine and the distance from the turning axis to the tilt sensor can be calculated at the same time (as will be described later).

  According to the present invention, it is possible to perform posture measurement at a low cost and easy for a specific pre-operation for performing posture measurement in both the pre- and post- cases.

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  Because of the nature of the invention, the configuration and its action are inseparably integrated, so here they will be described comprehensively without being separated. Further, the work machine itself to be measured does not particularly constitute the feature of the present invention, and therefore, for convenience, the reference numerals used for the hydraulic excavator (work machine) 1 already described with reference to FIG. Will be used.

  For example, when it is desired to measure the inclination angle θ of the boom (measurement object) 11 of the hydraulic excavator 1 by applying the present invention, as shown in FIG. Three inclination sensors S1 to S3 are arranged so that the positions do not line up in a straight line (that is, at positions corresponding to the vertices of the triangle T). Then, distances (lengths of the sides T1 to T3 of the triangle T) L1 to L3 between the three tilt sensors S1 to S3 arranged are measured and obtained as information. In this embodiment, the hardware configuration required for measuring the posture of the work machine is basically only this.

  Since the inclination sensors S1 to S3 can be arranged at arbitrary positions, it is not necessary to form tap holes or the like for attaching the inclination sensors S1 to S3 to the boom 11 in advance. For this reason, each of the inclination sensors S1 to S3 can be quickly installed on site by a simple fixing means such as a magnet (not shown) or an adhesive. The inclination information from the inclination sensors S1 to S3 may be brought to a computer (calculation means) not shown by wire, but if data collection is performed using a known wireless device (not shown), the hardware system Can be further simplified.

  Hereinafter, an example of a posture measurement method will be described in detail with reference to FIG.

  In the following description, reference signs ψ1, ψ2, and ψ3 are outputs (reading values) of the inclination sensors S1 to S3, ω is a turning angular velocity of the hydraulic excavator 1, and θo is a reference angle related to the arrangement position of the inclination sensors S1 to S3. , Θ represents the inclination angle of the boom 11 from the reference angle θo, respectively. Note that the values of the tilt sensors S1 to S3 in a stationary state at the reference angle θo are set to zero.

  The reference angle θo is the position of the sides T1 to T3 of the triangle T formed by the inclination sensors S1 to S3 at the position when the inclination sensors S1 to S3 are attached when the boom 11 is not turning (position corresponding to the broken line in the figure). The angle formed by the horizontal line H and the side having the angle closest to the horizontal line H (side T3 in the example of FIG. 2). In order to calibrate the reference angle θo, the vehicle turns while maintaining its posture (that is, θ = 0), and θ = 0 and outputs (reading values) ψ1, ψ2, and ψ3 of the inclination sensors S1 to S3 are inclined as described later. The value may be obtained by substituting it into the equation for obtaining the angle θ. Note that, by definition, when the inclination sensors S1 to S3 are arranged on the boom 11, if the two of the inclination sensors S1 to S3 are arranged to be “horizontal”, the reference angle θo is defined as follows. Since the value is “0”, there is no need to bother from the expressions (10) to (12), and the calculation for obtaining the inclination angle θ can be made easier.

  When the lengths L1 to L3 of the three sides are known, the three angles α1 to α3 of the triangle T are determined geometrically, and therefore the angles α1 to α3 are obtained by a method such as calculation and geometric measurement. Can be secured.

  Suppose that the outputs ψ1, ψ2, and ψ3 of the inclination sensors S1 to S3 are not equal to each other with reference to FIG. In this case, equations (1) to (3) are established as relational expressions of angular velocities when considering the centrifugal forces F1 to F3 generated in the respective inclination sensors S1 to S3.

g / r1 · tan (Ψ1) = ω ² (1)
g / r2 · tan (Ψ2) = ω ² (2)
g / r3 · tan (Ψ3) = ω ² (3)

  Here, the symbols ψ1 to ψ3 are angles (reference combined angles) obtained by measuring the direction of the combined acceleration of the gravitational acceleration g and the centrifugal forces F1 to F3 at the respective positions of the inclination sensors S1 to S3 from the vertical direction, and the inclination sensor S1. ~ S3 outputs the inclination of the boom 11 at that time with the direction of the reference composite angles Ψ1 to Ψ3 as a reference (output 0 degree). That is, the actual outputs (reading values) ψ1, ψ2, and ψ3 of the inclination sensors S1 to S3 are expressed by equations (4) to (6), respectively.

ψ1 = θ−ψ1 (4)
ψ2 = θ−ψ2 (5)
ψ3 = θ−ψ3 (6)

  Now, when r2-r1 = δ21, r3-r1 = δ31, and r3-r2 = δ32, when δ21, δ31, and δ32 are geometrically determined from FIG. 2, equations (7) to (9) Is established.

δ21 = r2−r1 = L3 · cos (θo + θ) (7)
δ31 = r3−r1 = L2 · cos (θo + θ + α1) (8)
δ32 = r3−r2 = L1 · cos (θo + θ + π−α2) (9)

  From the above equations, the gravitational acceleration g and the turning angular velocity ω are deleted and arranged, and the left side that depends on the change in the inclination angle θ and the right side that does not depend on the change in the inclination angle θ are summarized as follows (10). Equation (12) is derived.

  Since it is extremely difficult to solve these equations analytically, the inclination angle θ is obtained by numerically solving any one of the three equations, that is, the equations (10) to (12).

  Further, when the inclination angle θ is obtained by such processing, the reference synthetic angles Ψ1 to Ψ1 are obtained from the obtained inclination angle θ and the outputs ψ1, ψ2, and ψ3 of the inclination sensors S1 to S3 by the equations (4) to (6). Ψ3 is obtained, and using the obtained reference composite angles Ψ1 to Ψ3, the expressions (1) to (3), and the expressions (7) to (9), the turning radius (from the turning axis Oc) of each of the inclination sensors S1 to S3. ) R1, r2, r3 and turning speeds ω can also be obtained.

  On the other hand, when any two of the inclination sensors S1 to S3 indicate the same value (or a value that can be regarded as equal), the calculation can be performed more easily. For example, when the output ψ1 of the tilt sensor S1 is equal to the output ψ3 of the same S3 (when ψ1 = ψ3), the relationship between the tilt angles θo and θ can be expressed by the following equation (13).

    θo = (π / 2) −θ−α1 (13)

  Therefore, by using the inclination angle θ obtained by the equation (13), the turning radii r1, r2, r3 and the turning speeds ω of the respective inclination sensors S1 to S3 can be similarly obtained.

  By the way, for example, when the inclination sensors S1 to S3 are arranged on the boom 11, if the boom 11 is in the lowest position, two of the inclination sensors S1 to S3 are arranged to be “horizontal”. For example, since the reference angle θo is “0”, it is not necessary to bother to obtain the reference angle θo from the equations (10) to (12), and the calculation itself for obtaining the inclination angle θ is easier. I mentioned earlier what I can do.

  Similarly, at the time of actual attachment, it may be known at which position of the measurement object the inclination sensor is attached. As described above, various specifications of the hydraulic excavator 1 itself are known by design. Using these known information or specific conditions established at the site not only simplifies calculations, but in some cases, only one tilt sensor can be installed per measured object. Can build a simple system.

  Although various variations are possible, as an example, a method of measuring the attitude of a hydraulic excavator with a total of four tilt sensors, one each for the work machine main body, the boom, and the bucket is shown. However, it is assumed that the mounting position of each inclination sensor is known, the excavator is placed on a horizontal ground, and the reference angle θo is “0”.

  FIG. 3 shows the relationship between the specifications around the inclination sensor Sb attached to the boom 11 and the inclination sensor Ss attached to the work machine main body 3.

If the attachment position of the inclination sensor Ss attached to the work machine body 3 (distance from the turning axis Oc = turning radius rs) is known, rs / g = ω ² is established in relation to the generated centrifugal force Fs. Thus, the turning angular velocity ω of the work machine main body (and hence each measured object) can be obtained. If another tilt sensor (not shown) is attached at a position symmetrical to the tilt sensor Ss with respect to the swing axis Oc in the work machine main body 3, the swing angular velocity ω can be obtained without being on a horizontal plane.

  The distance Ld from the turning axis Oc to the turning center 11 </ b> A of the boom 11 is known from the design of the excavator 1. Here, assuming that the distance La from the rotation center 11A to the tilt sensor Sb attached to the boom 11 is known, the following equations are obtained. In addition, the definition of each code | symbol is based on the previous example.

g / ra · tan (Ψa) = ω ² (14)
ra−Ld = La · cos θ (15)
ψa = θ−ψa (16)

Therefore, from (14) to (16),
tan (θ−ψa) / (Ld + La · cos θ) = ω ² / g (17)
The relationship is obtained. Since the turning angular velocity ω has already been calculated from the output of the tilt sensor Ss, the tilt angle θ can be obtained from the equation (17).

  Since the distance from the pivot center 11A of the boom 11 to the arm pivot shaft (not shown) of the boom 11 is known by design, the distance from the position of the pivot center 11A of the boom 11 and the inclination angle θ of the boom 11 is determined. The position of the arm rotation axis can be specified. Therefore, the inclination angle of the arm 12 can be obtained in exactly the same manner, and the inclination angle of the bucket 13 can be obtained in order in the same manner. As a result, finally, the position of the tip of the bucket 13 can also be known.

  In this way, when there is known information or specific conditions other than the distance between the tilt sensors, the calculation of the tilt angle θ can be simplified, and in some cases, the number of tilt sensors themselves is two or Can be reduced to one. Variations can be considered in various ways on site or for each mounting mode. As is clear from the above example, when a tilt sensor is mounted on the work machine body, its mounting position can be determined with respect to the pivot axis (dynamically In particular, it often functions extremely effectively to simplify the calculation of the turning angular velocity.

  In the above embodiment, basically, three tilt sensors are mounted at arbitrary positions (considering not to be on one straight line), and the hardware for measurement is simply measured by measuring the distance between the tilt sensors. System construction is completed. That is, there is no special “attachment designation place”, and it is not necessary to previously form a tapped hole or the like in the measurement object on the premise that the sensor is attached. Since the “tilt sensor” is attached, it can be easily attached with a magnet or an adhesive, and expensive equipment such as a GPS receiver is not required. For this reason, for example, in order to check the behavior of many existing work machines for the construction of an automatic control system for work machines, it is easy to quickly build a posture measurement system on-site for existing work machines. To be able to.

  Needless to say, it is very important to grasp the posture of the work machine when constructing an automatic control system or a driving assistance system in order to realize further advancement of the work machine.

  For example, if it can be confirmed that the attachment (measurement object) of the work machine is at the top position where it is swung up to the maximum, it cannot be swung up any more as the next work (because it can only be lowered). It can be seen that it is not necessary to maintain the engine power at a predetermined position equal to or higher than the idle in preparation for the raising command. Therefore, it is possible to quickly reduce the engine power to a power equivalent to an idle. Thereby, energy saving and noise reduction can be realized without causing any trouble in operation.

  Also, when the distance from the turning axis of the attachment is large, the peripheral speed (moving speed in the horizontal direction of the attachment) increases even when turning at the same turning angular speed, so the surroundings are safe and the work machine itself is prevented from falling. Therefore, various controls such as suppressing the upper limit of the turning angular velocity can be performed.

  In the present invention, although only the tilt sensor is basically disposed, the influence of the turning of the work machine can be removed and the posture such as the tilt angle of the object to be measured can be measured purely. By performing such data processing, the height of the monitor point and the turning radius can be obtained, and further, the turning angular velocity of the work machine and the distance from the turning axis to each tilt sensor (turning radius) can be obtained.

  In the present invention, an attitude measurement system can be constructed with only a tilt sensor, but installation of sensors other than the tilt sensor is not denied.

  In realizing an automatic control system for work machines, grasping (measuring) the current posture of the object to be measured, or developing or improving an automatic control system, various (new or existing) work machine behaviors It can be used to acquire data used for simulation.

The front view which shows a mode that the three inclination sensors were attached to the working machine with which an example of embodiment of this invention is applied. The diagram which shows the relationship of each item around the said inclination sensor A diagram corresponding to FIG. 2 showing an application example of the present invention when specific data is known and a specific condition is established at the site. A perspective view showing an example of a conventional hydraulic excavator (with a position control system)

Explanation of symbols

11 ... Boom (measurement object)
S1 to S3, Ss, Sb ... inclination sensors L1 to L3 ... distances between inclination sensors α1 to α3 ... angles of sides formed by the inclination sensors ψ1, ψ2, ψ3 ... inclination sensor outputs (reading values)
ω ... turning angular velocity θo ... reference angle Ψ1 to Ψ3 ... angle measured from the vertical direction of the combined acceleration of gravity acceleration and centrifugal force (reference combined angle)

Claims (6)

In a method of measuring the attitude of a work machine capable of turning,
Procedure for placing the tilt sensor on the workpiece to be measured by the work machine,
A procedure for obtaining output information of the tilt sensor during turning of the work machine;
Using the output information of the tilt sensor at the time of turning, a procedure for obtaining a posture including the tilt angle during operation of the measured object;
A method for measuring a posture of a work machine, comprising: In claim 1,
As the tilt sensors, three tilt sensors are arranged at an arbitrary position on the workpiece to be measured by the work machine so as not to be aligned in a straight line, and the distance between the three tilt sensors is further measured. And comprising the steps of:
A posture measurement method for a work machine, characterized in that a posture including a tilt angle during operation of the object to be measured is obtained by combining the output information of each tilt sensor at the time of turning with distance information between the tilt sensors. . In claim 1,
As the tilt sensor, one or two tilt sensors are arranged at an arbitrary position on the measurement object to be measured by the work machine, and
By combining the output information of the one or two tilt sensors at the time of turning with one or more known information separately obtained with respect to specific specification information of the tilt sensor or the work machine, A method for measuring a posture of a work machine, characterized in that a posture including an inclination angle during operation of a measured object is obtained. In any one of Claims 1-3,
In addition to the tilt sensor, a separate tilt sensor is disposed at a specific position of the main body of the work machine,
An attitude measurement method for a work machine, characterized in that an attitude including an inclination angle during operation of the object to be measured is obtained also using a turning angular velocity obtained by the separately provided inclination sensor. In a device that measures the attitude of a work machine capable of turning,
An inclination sensor disposed at an arbitrary position on the measurement object to be measured by the work machine, and at least using output information during turning of the work machine by the inclination sensor; An attitude measuring device for a working machine, comprising: an arithmetic means for calculating an attitude including an inclination angle during operation of the measuring body. In claim 5,
In addition to the inclination sensor arranged on the measured object, an inclination sensor is also arranged on the main body of the work machine,
The calculation means includes an inclination angle during operation of the measurement object using output information of the inclination sensor arranged on the measurement object and output information of the inclination sensor arranged on the main body of the work machine. A posture measuring device for a work machine characterized by calculating a posture.

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