JPH0445041B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a device for calculating the spatial rotation angle of a moving body rotating in space.

[Summary of the invention]

In the present invention, a spatial rotation angle is calculated by using a very light and small inertial support type measuring device and integrating the output value from this measuring device twice.

[Problems with conventional technology]

Measuring the spatial rotation angle of a moving body rotating in space using an inertial force measuring device generally requires a large-scale measurement system such as a gyro device, an accelerometer, or a combination thereof. Although these are good for motion analysis of large moving objects such as ships, airplanes, and flying objects, they are not suitable for use by being attached to manipulators or human limbs for controlling traveling robots or artificial hands. Until now, there has been no transducer system that is compact and can accurately measure spatial rotational motion suitable for such applications.

Therefore, an object of the present invention is to provide a practical device that can be easily attached to a human body or a manipulator, and that can easily measure the spatial rotation angle in a state of movement.

[Means for solving problems]

The present invention uses an inertial force measuring instrument as a very light and small inertial support type measuring instrument, which is based on a commercially available DC ammeter component that is small and has a small driving force for moving parts, and has the necessary parts added to it. do. This measuring instrument has a DC ammeter type measuring unit and an integrating circuit.

The present invention is divided into two inventions depending on whether a single measuring unit or a plurality of measuring units are provided. A measuring instrument equipped with one or more such measuring units is attached to a moving body so that the axis of the moving coil of the measuring unit coincides with a direction perpendicular to the rotation plane of the moving body rotating in space. The output voltage generated in the moving coil when the unit rotates is measured (totaled in the case of multiple units), and this measured value is integrated and used as the output of the measuring device. The spatial rotation angle is calculated by integrating the output value of this measuring device twice.

[Effect]

The integral value of the output voltage of the measuring unit is proportional to the angular acceleration of the moving body, and by further integrating this twice, the rotation angle output can be obtained.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

FIG. 1 shows an example of a measuring instrument used in the first invention (that is, it has a single measuring unit), in which A is a perspective view and B is a plan view. In these figures, M indicates the measuring instrument as a whole, u indicates a measuring unit therein, and C indicates a measuring circuit section. The measuring unit u has a DC ammeter-like structure. That is, the moving coil 1 is the permanent magnet 2
It is rotatably suspended and supported in a uniformly distributed magnetic field in the gap between the circular yoke 3 and the circular yoke 3 via a spiral spring 4 for maintaining the zero position. Now, the space drifting system is O-XYZ, the coordinate system of the moving body is O-ξηζ, and the moving body has an angular velocity ω, with its Oζ axis aligned with the space drift axis OZ,
Assume that rotational motion is performed with angular acceleration ω〓 (plane ξOη is in the space XOY plane). On the other hand, the measurement unit u on this moving body is attached to the moving body so that the axis passing through the coil axis O coincides with the Oζ axis of the moving body, and the direction perpendicular to the coil coincides with the Oη axis. shall be.

Next, the operation of the measuring device M will be explained with reference to FIG. In this figure, parts corresponding to those in FIG. 1A are given the same reference numerals. a in measurement circuit section C
indicates an amplifier, and in ₀ indicates an integrating circuit. When the moving body rotates with the angular acceleration ω as described above, the moving coil 1 twists the spring 4 in response to the inertia torque T _i and rotates by the deflection angle θ. At this time, the moving coil 1 moves at an angular velocity across the uniformly distributed magnetic flux in the air gap.
An electromotive force E proportional to dθ/dt is induced.

The equation of motion of the moving coil 1 in this case is as follows, where I is the moment of inertia of the moving part, r is the braking constant, and k is the control constant of the spiral spring.

Id ² θ／dt ² +rdθ／dt＋kθ＝T _i ……(1) Here, T _i ＝Iω〓 ……(2) Also, in equation (1), the braking rate of the motion system (movable part) is ε, self If the vibration period is T ₀ , the following relationship holds true.

Therefore, the deflection angle θ(t) of the movable part when the external force T _i is a function that changes with time, that is, T _i (t).
performs a responsive rotational motion with a phase difference and a gain ratio with respect to T _i (t) under the condition of equation (3). Now, for the sake of simplicity, if we treat the ideal state under the critical condition (ε/T ₀ =2π), we get θ=T _i /k=I/kω〓 ……(4).

On the other hand, the induced voltage E can be expressed by the following equation, where n is the winding of the movable coil 1, A is the area, and B is the magnetic flux of the air gap.

E=BnAdθ/dt...(5) Therefore, in Fig. 1B, the moving coil 1 of the measuring unit u has an inertial force T _i as shown by the arrow.
(Iω〓) is added, and a voltage E is generated from the output terminal _t0 of the moving coil 1. This voltage E is measured by the circuit section C.
and is applied to the integrating circuit in ₀ via an amplification factor a (for simplicity, the amplification factor is assumed to be 1). If the output value is E ₀ , then E ₀ =∫Edt=BnAθ=BnA/kIω〓 (6).

BnAI/k of the right side BnA/kIω of equation (6) is this measuring device M
Since it is a constant, BnAI/k is considered as the weight of the scale of the angle system, and if the angular acceleration expressed in this scale is Ω〓, we obtain E ₀ =Ω〓 ...(7). That is, the output E ₀ of the measuring device M always shows a value proportional to the angular acceleration of the moving body. When this is applied to a double integration circuit as shown in Figure 3, E ₀ (Ω〓) is integrated by the first integration circuit in ₁ and becomes an output (-Ω) corresponding to the rotational angular velocity Ω. (-Ω) is further integrated by the second integration circuit in ₂ to obtain the rotation angle output δ.

Figure 2 shows two examples of measuring instruments used in the second invention (that is, having a plurality of measuring units); Figure A has three measuring units, and Figure B has six measuring units. Indicates one with a measuring unit. In these figures, the entire instrument is shown as M ₃ and
It is designated by M ₆ and is distinguished from the reference numeral M in FIG. However, the configurations of each measurement unit U and attached measurement circuit section C are the same as those in FIG. 1. Therefore, parts corresponding to those in FIG. 1 are given the same reference numerals. In Figure 2, all measurement units u are the same size, and each unit has a movable axis.
Installed parallel to Oζ. The output terminals of the movable coils 1 of each unit are connected in series as shown by broken lines and connected to the input of the amplifier a of each measuring circuit section C. That is, three coils are connected in series in FIG. 2A, and six coils are connected in series in FIG. Amplifier a is a high input impedance amplifier that accurately converts an input voltage into a measured output.

Now, consider a case where a moving body to which measuring instruments M ₃ and M ₆ are attached performs a rotational movement of ω〓. In this case, if the motion system constant values I, k, r of the movable part of each measurement unit u, and hence T ₀ , ε, and the electromagnetic system constant values B, n, and A are the same for each unit, then
The relationships of equations (1) to (5) hold true in each unit.
Therefore, in each measurement unit u, E in equation (5)
An equal amount of voltage is induced, and a voltage of 3E in the case of FIG. 2A and 6E in the case of FIG. 2B is introduced into the amplifier a of each measuring circuit section C. This amplifier a is
As described above, since the amplifier has a high input impedance, the respective summed input voltages are accurately converted into measurement voltages as they are. In this case as well, for the sake of simplicity, the amplification factor is assumed to be 1, and the output voltage is subsequently applied to each integrating circuit in ₀ , and the output values 3E and 6E ₀ of the measuring devices M ₃ and M ₆ are determined.

Similarly, in general, a measuring device M _n having m measuring units has an output voltage of mE ₀ .
Therefore, as in the conversion of equations (6) and (7) in the case of a single unit measuring device M, mE ₀ = (mBnAI/k)ω〓, so mBnAI/k can be converted to ω〓 measurement by the measuring device _Mn. Considering this as the weight of the scale of the angular system, and assuming that the angular acceleration ω〓 expressed in this scale is Ω〓 _n , we get mE ₀ = Ω〓 _n ……(7m).

In other words, the angular acceleration Ω〓 _n determined by the measuring device M _n shows the same value as the Ω〓 value determined for a single unit, but the measurement accuracy of Ω〓 _n is Ω〓 The measurement accuracy of _n is Ω〓
m times. That is, compared to the case of a single unit, the measurement accuracy is improved three times in FIG. 2A and six times in FIG. 2B. Please note that measuring instruments with multiple units
In the case of M _n , the measurement accuracy can be improved in this way, but since the constants of the mechanical system and electromagnetic system of each measurement unit u are the same as in the case of a single unit, the measurement time constant will not change. Not at all.

The output value Ω〓 _n of the above measuring device M _n is introduced into the double integration circuit in Figure 3 as in the case of Figure 1, and the rotation speed Ω _n and rotation angle δ _n are determined. The measurement accuracy of the values Ω _n and δ _n is also increased by m times. In other words, compared to the single unit measuring device M, the measurement in Fig. 2A is three times as large.
In Figure 2 (b), a six-fold improvement in accuracy can be obtained.

〔Effect of the invention〕

(a) The first invention, that is, the one having a single measurement unit, is advantageous for use in a swing sensor (swing type sensor), etc., where the spatial rotational angular acceleration, ie, ω is large. For example, in order to operate a prosthetic hand worn by a person with a disability such as an upper limb deficiency, two swing sensors that can measure rotation angles in front, back, left, and right are attached to the head, and by swinging the head back and forth, the prosthetic arm can be operated. A driving signal can be given. In this case, the spatial rotation angles in the vertical and horizontal directions can be set within a specified range while keeping the magnitude of ω〓 constant.

(b) The second invention, that is, one having a plurality of measurement units, is suitable for controlling the motion of a robot arm or analyzing the motion of a human body. In these movements,
The minimum angular acceleration limit is fixed, and even if the angular acceleration value is gradually increased, the maximum limit is _limited . The number of measurement units u is selected based on:

Also, a multi-unit measuring instrument can be used in place of an inertial device such as an aviation gyro. In this case, the minimum measurable angular acceleration will determine the spatial orientation drift rate, ie, measurement accuracy. Therefore, in such a case, it is necessary to increase the number of measurement units to the extent that they can respond to the minimum angular acceleration.

(c) In both the first and second inventions, a measuring device using one or more commercially available DC ammeter type measurement units can be attached to a moving body to measure its spatial rotation angle. Moreover, since the measurement unit has a small volume, it has the advantage that a large number of measurement units can be attached to a moving body, including a human body, a robot, and other general moving objects, filling the minimum coordinate space of the moving body necessary for measurement. It also has the advantage of low manufacturing costs.

[Brief explanation of drawings]

Fig. 1 shows an example of a measuring device used in the first invention, Fig. 2 shows an example of a measuring device used in the second invention, and Fig. 3 shows a double integration device used in the first and second inventions. An example of a circuit is shown. 1... Moving coil, u... Measuring unit, T _i ...
...Inertia torque, E...Output voltage of moving coil,
in ₀ ...integration means, in ₁ and in ₂ ...twice integration means,
δ (δ _n )... Spatial rotation angle.

Claims (1)

[Scope of Claims] 1. In a DC ammeter type measurement unit installed on a moving body rotating in space with the axis of a moving coil aligned in a direction perpendicular to the rotation plane of the unit, when the moving body rotates, the unit A measuring device configured to measure the output voltage of the coil caused by rotational movement within the air gap magnetic field of the coil due to inertial torque acting on the movable part of the coil, and to integrate the measured value; A spatial rotation angle calculating device comprising means for integrating an output value twice, and automatically calculating a spatial rotation angle when the moving body rotates. 2. In a plurality of DC ammeter-type measurement units installed on a moving body rotating in space with the axes of the respective moving coils aligned in a direction perpendicular to the rotation plane of the unit, when the moving body rotates, the A measuring device configured to add and measure output voltages of the coils caused by rotational motion in the air gap magnetic field of the coils due to inertial torque acting on the movable part, and to integrate the measured values; 1. A spatial rotation angle calculating device comprising means for integrating an output value of the device twice, and automatically calculating a spatial rotation angle when the moving body rotates.