JPH0582525B2 - - Google Patents

Description

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

[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. These devices are often used for motion analysis or navigation measurements of large moving objects such as ships, airplanes, and flying objects, and are small enough to be attached to human limbs or manipulators for human motion analysis or hand control of moving robots. However, until now, there has been no transducer system that can faithfully measure spatial rotational motion.

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 to easily measure the spatial rotation angle in a state of movement.

[Summary of the invention]

For this reason, the present invention uses a very light and small inertial support type measuring instrument, uses a dynamic torque balance method for its measurement method, and uses a compact and integrated computer to process the output value from the measuring instrument at high speed. Processed to calculate rotation angle.

The inertial support type measuring instrument used in the present invention requires a movable part that is small and light in shape and has a small driving force. An inertial measuring instrument is used, with simple small DC ammeter parts as the base, and parts with the necessary functions added to it. Then, a pair of inertial wheels whose weight is balanced with respect to the moving coil is attached to the pointer of this ammeter-type moving part to increase the moment of inertia of the moving part, and detect the inertial force torque acting on it during movement. By integrating twice the output of the dynamic torque measuring device, which is configured to amplify and output the current to the outside and also feed back the current negatively to the coil via a feedback circuit that operates proportionally, the space of the moving body can be calculated. The rotation angle is now calculated. Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

〔Example〕

FIG. 1A is a configuration diagram showing an example of a measuring instrument used in the present invention. The measuring instrument shown in the figure is composed of a main body u having a movable part, a detection part d, an amplification part a, and a feedback circuit f. In the main body u, MG is a permanent magnet, SY
indicates a sublayer iron plate yoke, SF indicates a soft iron core, and SY and
A moving coil 1 supported on an axis O is housed in the gap between the SFs. In addition, the moving coil 1 has
Pointer 2 is connected. This inertial force measuring device with an ammeter type movable part is attached to a rotating or rotating body. FIG. 1B is a perspective view showing the relationship between the mounting postures. In this figure, the spatial coordinate system is O-
XYZ, the coordinates of the moving body are O-ξηζ, and the circular moving body has the Oζ axis coincident with the spatial coordinate axis OZ, and with this as the axis, the angular velocity ω and the angular acceleration ω〓 (the surface ξOη is
It is assumed that the object is rotating (in the XOY plane). On the other hand, the main body u of the measuring instrument 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 of the pointer 2 coincides with the Oη direction that crosses the axis O.

Referring again to FIG. 1A, a pair of inertial missing wheels 13a, 1 whose weight is balanced are placed at the end of the pointer 2 on the coil 1 side.
3b is attached to increase the moment of inertia of the movable part including the coil 1, and apply inertia torque to the movable part as input torque when the moving body rotates.
In addition, pairs of light emitting elements and light receiving elements 5 ₁ -6 ₁ and 5 2 -6 ₂ are provided on the measuring device fixing parts _{4 1 and} 4 ₂ at small intervals with both sides 3 1 and _{3 2} of the pointer 2 in between, respectively. . The light emitted from each light emitting element 5 ₁ , 5 ₂ is reflected by the corresponding pointer both sides 3 ₁ , 3 ₂ and is transmitted to the light receiving element 6 .
₁ and 6 ₂ . In addition, the above guideline 2
At the zero (equilibrium) position that coincides with the Oη direction, the small spacing on both sides is set to the same amount, and when the moving body rotates, the input torque to the moving parts including the moving coil 1
The difference torque (Ti - Tf) between Ti and the torque Tf due to the current negatively fed back to the movable coil 1 is applied to the movable part of the measuring device. As a result, the small interval between the photodetectors changes, and the detection currents of both sides change correspondingly, and the difference output from resistors r ₁ and r ₂ is amplified and taken out from the output terminal 8 at the same time. Negative feedback is provided to the movable coil 1 via the feedback circuit f. Note that the detection section d does not necessarily have to be based on light.

FIG. 2 is a block diagram for explaining the operation of the measuring instrument described above. In the figure, Ti is the inertial input torque, Tf is the torque due to the current negatively fed back to the coil, ε is the difference between Ti and Tf, Gd is the transfer function of the detection section d, Ga is the gain of the amplification section a, and Eo is the The output voltage, Gf, indicates the gain of the feedback circuit f. The following relationship holds between these.

Ti−Tf=ε Tf=EoGf Eo=GdGaε ...(1) From equation (1), Eo/Ti=GdGa/1+GfGdGa ...(2) If the gain of amplifier section a is large and Ga≫1, Eo/Ti≒ It becomes 1/Gf (3). That is, the output voltage Eo is approximately proportional to the inertial input torque Ti.

Here, if the moment of inertia of the movable part is I, and the spatial turning angular acceleration of the moving body is ω, then Ti=Iω (4) holds true. As shown in this equation, Ti does not include any effects of linear acceleration or gravity of a moving body. The only thing that affects Ti is the rotational angular velocity ω〓 of the moving body itself. Therefore, the frequency band of Ti is usually monotonic. The frequency characteristic between inertial input torque Ti and output voltage Eo is
It is desirable that the gain remains constant while the frequency band of Ti changes from zero to the upper limit frequency considered. Therefore, to accommodate this, the circuit configuration of the feedback loop is of a proportional type.

FIG. 3 is a circuit diagram showing an example of such a feedback loop. In the same figure, the feedback circuit f has a voltage
It is configured to perform a proportional operation that divides Eo into a ratio of resistor Rp ₂ and resistor Rp ₁ to provide a feedback current to the coil. The transfer function in this case is when Ga≫1
Rp ₁ / Rp ₂ . With this circuit configuration, Eo=Rp ₂ /Rp ₁ Ti (5) is obtained. Eo can be expressed as an inertial force in an angular system using equations (5) and (4). That is, we obtain Eo=Rp ₂ /Rp ₁ Iω〓.

Here, since Rp ₂ /Rp ₁ I is a constant of this measuring instrument, consider Rp ₂ /Rp ₁ I as the weight of the scale of the angular system, and if the angular acceleration expressed in this scale is Ω〓, then Eo−Ω 〓 ……(6) is obtained. In other words, Eo always provides an output proportional to the angular acceleration of the moving body.

Therefore, as shown in Fig. 4, the output -Ω corresponding to the turning angular velocity Ω is obtained by integrating Eo (Ω) using the first integration circuit in ₁ , and this is further integrated into the second order integration circuit in 1. The turning angle output θ can be obtained by integrating by the integrating circuit in ₂ . Fifth
The figure shows a specific example of the above-mentioned double integration circuit.

FIG. 6 is a waveform diagram for explaining the operation of the two-time integration circuit of FIG. In the same figure, a is the angular acceleration Ω,
Figure b is a waveform diagram of the angular velocity Ω, and Figure c is a waveform diagram of the rotation angle θ. When time t=t ₀ , Ω=0, θ=0,
Angular acceleration is constant during time t=T ₀ to t ₁ (=Δt) (a)
Then, Ω〓 _t0〜t1 = a Then, Ω _t1 =∫ ^t1 _t0 adt＝aΔt θ _t1 =∫ ^t1 _t0 aΔt dt=a/2(Δt) ² , and Ω〓, Ω, θ are as shown in Figure 6. Follow the progress from A to B in the first half of the left side.

Next, if the angular acceleration is kept constant (-a) during t=t ₁ - t ₂ (=Δt), Ω〓 _{t1 - t2} = -a Then, Ω _t2 = Ω _t1 +∫ ^t2 _t1 (- a) dt = aΔt−aΔt=0 In other words, the angular velocity decelerates from aΔt of Ω _t1 to t
= 0 at t ₂ . Also, since θ _t2 −θ _t1 =a/2(Δt) ² , we obtain θ _t2 =a/2(Δt) ² +a/2(Δt) ² =a(Δt) ² . Therefore, Ω〓, Ω, θ follow the course from B to C in the right half of FIG. 6, and the rotation angle θ shows a(Δt) ² at t=t ₂ .

1 at one end of the pointer, as shown in Figure 1.
A small ammeter-type inertial force torque measuring instrument having a pair of inertial missing wheels can be constructed compactly as a whole by incorporating a detecting section d, an amplifying section a, and a feedback circuit f in a main body u. Additionally, the accompanying electronic calculation unit, which mainly consists of a primary integration circuit and a secondary integration circuit, is integrated into a compact size, making it possible to mount all of these devices on the human body or a robot manipulator. It is.

〔Effect of the invention〕

As explained above, according to the present invention, the motion analysis of the human body can be performed by attaching it to the extremities of a working human being or a robot manipulator, etc. in motion, and is capable of measuring spatial rotation angles that have not been available until now for applications such as manipulator control. It can be used as a container.

[Brief explanation of the drawing]

FIG. 1A is a configuration diagram showing an example of a measuring instrument used in the present invention, FIG. Figure 3 is a circuit diagram showing an example of a feedback loop.
Figure 4 is a block diagram showing the principle of calculating the rotation angle using a two-time integration circuit, Figure 5 is a circuit diagram showing a specific example of the two-time integration circuit shown in Figure 4, and Figure 6 is a waveform for explaining its operation. It is a diagram. ζOη...Rotation plane of the moving body, Oζ...Direction perpendicular to the rotation plane, 1...Moving coil, OZ...Rotation axis of the moving coil, 2...Pointer, 13a, 13b...1
Pair of inertial missing wheels, Ti...Input torque, d...Detection section, a...Amplification section, 8...Output end, f...Feedback circuit, Tf...Torque due to negative feedback current, in ₁ and in ₂
...First and second integration circuit, θ...Spatial rotation angle.

Claims (1)

[Scope of Claims] 1. A moving coil having a rotation axis perpendicular to the rotation plane of the moving body, a permanent magnet facing the moving coil through the rotation axis, and rotation of the moving coil. A dynamic torque measuring device comprising a pair of inertial wheels mounted around a shaft with balanced rotational moments, a pointer attached to the moving coil, and a detection means for detecting displacement of the pointer from the equilibrium position. The output signal of the detection means is amplified and taken out, and the amplified output is negatively fed back to the movable coil via a proportional feedback circuit, and the amplified output of the detection means is integrated twice. A spatial rotation angle calculating device configured to calculate a spatial rotation angle when the moving body rotates.