JPH04115882A - Suspension mechanism with constant tension - Google Patents

Abstract

PURPOSE:To repeatedly perform the simulation of the motion of an object in a gravityfree space over a long time, by providing a suspension position moving mechanism which moves the suspension position of a wire with the degree of freedom in the horizontal direction so that the wire becomes vertical. CONSTITUTION:The tension applied on a wire 102 which suspends an object body 101 is detected by a tension sensor 103, and the wire 102 is wound/rewound by a winding mechanism 104 so that this tension becomes a constant value by a control part 105. Also the suspension position of the wire 101 is moved by a suspension position moving mechanism 106 so that the wire 102 becomes vertical at all times, so as to cause no horizontal component force of the tension.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Conventional technology Problems to be solved by the invention Means for solving the problems (Fig. 1) Working examples (Figs. 2 to 42) 1. Basic method of zero-gravity simulation system 1.1. Online weightless simulation experiment system■1.1.1. Overall configuration a, simulation data creation department, multi-jointed structure (space robot) C0 zero gravity simulator 1.1.2. Element parts a, constant tension suspension mechanism part ■, vertical movement mechanism a, suspension tension adjustment method.

Port, hanging position and gimbal, counterbalance server, wire winding mechanism part 2, configuration of tension sensor and control device, operating mechanism in horizontal plane (hanging arm) port 1 main body support drive part, etc. 1.1.3. Online data creation method 1.1.4. Based on online data (cooperative control operation 1.2. Offline zero gravity simulation experiment system ■1.2.
1. Overall configuration 1.2.2. Element part a, angle detection sensor ■, optical angle detection sensor ■9 component force detection sensor 1.2.3. Control operation 1.3. Online zero-gravity simulation system■1.3.
1. Overall configuration 1.3.2. Element part a, robot-based reaction 1.3.3. Control operation ■, 4. Online weightless simulation experiment system I11.4
．． 1 Overall configuration 1.4.2. Control operation 2, hanging method 2, l1 center of gravity vertical hanging method 2.2. Static balance method 2.3. Compromise method 3, control of hanging arm 3.1 Algorithm for vertical holding method in hanging direction 3.21 Constant tension control by winding mechanism 3.2.1. l-Lux control method ■ a. Overall configuration, configuration of each element C6 Control method 3.2.2. Torque control method II a. Overall configuration, control method 3.2.3 Torque control wholesale method ■ a. Overall configuration, control method 3.2.4 Speed control method % formula % 3.3. Specific configuration of control circuit 4, simulation computer system 4.1. System configuration ■ 4.2. System configuration ■ Effects of the invention [Summary] Regarding a constant tension suspension mechanism used in a zero gravity simulation experiment device that simulates the behavior of a space robot in zero gravity space using hardware on the ground, we have developed a device suitable for realizing a zero gravity simulation experiment device. The purpose is to provide a constant tension hanging mechanism with a simple configuration, which includes a wire for hanging a target object, a tension sensor that measures the tension applied to the wire, a winding mechanism that winds and unwinds the wire seven times, and a tension sensor. A controller that controls the winding and unwinding of the winding mechanism so that the tension applied to the wire is constant based on the measured value of and a hanging position moving mechanism section that moves the hanging position by holding it.

[Industrial Application Field] The present invention relates to a constant-tension suspension mechanism used, for example, in a zero-gravity simulation experiment device that simulates the behavior of a space robot in zero-gravity space using hardware on the ground.

Do you see a space station or space platform? j11
In order to configure and operate space infrastructure such as satellites and space experiment modules, assembly, maintenance, inspection, and
Repairs and other support work must be carried out in space. Performing this overboard work by humans as in the past poses problems in terms of safety and work time limitations. Therefore, there are expectations for the development of space-moving or truss-moving space robots with high operational capabilities that can replace manned work.

To make robots perform highly functional tasks in outer space,
It is essential to perform reaction force control that takes into account Guinamidukkus under zero gravity, and the robot control law and remote control planning,
It is necessary to research and develop maneuvering techniques. As a method to accurately understand the behavior of robots during work, there is a strong need for a hardware simulation device that directly simulates the movements of space robots in zero gravity on the ground.

[Prior Art] Conventionally, the following methods have been devised and implemented as methods for directly simulating the motion of objects in a zero-gravity state on the ground.

■Simulate weightless motion in a plane on a surface plate using air levitation or magnetic levitation.

■Put an object in a water tank, use buoyancy to cancel gravity, and simulate zero-gravity behavior in three dimensions.

■Create a zero-gravity state using a falling tower or aircraft, and operate within that state.

-H Notes ■The robot's motion is limited to a two-dimensional plane, ■■ cannot realize the dynamic characteristics of outer space due to fluid resistance, and ■■ is limited to short-term motion simulation.

Therefore, a method has been proposed in which the object is suspended by a wire and the tension applied to the wire cancels out the object's gravity to create a simulated weightless state on the ground. This method requires that the object be suspended by a wire with constant tension.

Various methods can be considered for suspending this target object. For example, as shown in Figure 8, there is a balloon method in which an arm is suspended from a balloon, a counterbalance method in which an arm is suspended by a counterbalancer, and a counterbalance method in which an arm is suspended by a counter balancer. There are constant force spring types (Conston springs) in which a wire with a suspended arm is wound around a wire winding drum and unwinded, and a winding type in which the arm is suspended using a wire winding drum and a winding motor.

[Problems to be solved by the invention] When attempting to simulate weightlessness by suspending a multi-jointed structure with a complex structure, such as a space robot, using a wire, the mechanism for suspending the wire must be large-scale. Therefore, there is currently no device that simulates a zero-gravity state using a wire suspension method for a multi-joint structure.

Therefore, in order to realize a zero-gravity simulation experiment device such as a multi-jointed structure, a constant tension suspension mechanism with a compact configuration is required. For this purpose, a winding method that can easily respond to changes in the suspension gravity and aim for compactness and high precision is suitable for a constant tension suspension mechanism.

The present invention has been made in view of the above circumstances, and its purpose is to provide a simple structure with a constant tension suspension mechanism using a winding method suitable for realizing a zero-gravity simulation experiment apparatus for multi-jointed structures and the like. Our goal is to provide the following.

[Means to solve the problem] FIG. 1 is a diagram explaining the principle of the present invention.

In the present invention, as a first form, the target object 101
a tension sensor 103 that measures the tension applied to the wire 102; a winding mechanism section 104 that winds up and unwinds the wire seven times; The control unit 1 controls the winding 7 unwinding of the winding mechanism unit 104 so that
05, and a hanging position moving mechanism section 106 that moves the hanging position of the wire 103 with a degree of freedom in the horizontal direction so that the wire 102 becomes vertical.

Further, in the present invention, as a second embodiment, the above-mentioned first
In the constant tension suspension mechanism of the form, the target object 101 is a multi-joint structure having a multi-joint arm with 6 degrees of freedom,
This arm is configured to be suspended by a plurality of wires 102, and includes the tension sensor 103, the winding mechanism section 104, the control section 105, and the suspension position moving mechanism section 106.
is provided corresponding to each of these multiple wires,
The suspension position movement mechanism section 106 is connected in multiple stages, with a bending axis and an adjacent linear axis as one unit of joint configuration,
A constant-tension suspension mechanism is provided that includes a horizontal articulated cylindrical suspension arm that mounts a next-stage bending shaft and/or a winding mechanism on a table of a straight shaft.

Further, in the present invention, as a third embodiment, the above-mentioned second
In the constant tension suspension mechanism of the form, there are three-axis orthogonal coordinate joints that take three-dimensional positions, rotation that takes three-direction postures,
It consists of joints with a total of 6 degrees of freedom (3 axes of flexion), and 2 degrees of freedom in the horizontal plane.
Connect the vertical axis rotation posture freedom degree to the table that takes the axis position freedom degree, connect the vertical axis translation position freedom degree in series to this, and furthermore, the remaining two axes bending and rotation posture freedom degrees are perpendicular to each other. The multi-joint structure base is connected to the rotating joint at the tip, and the bending axis of the first stage of the hanging arm is connected between the degree of freedom of vertical rotation and the degree of freedom of vertical movement position. A constant tension suspension mechanism with a support drive is provided.

Further, in the present invention, as a fourth embodiment, the above-mentioned second
, or a third form of a constant tension suspension mechanism, further comprising a gimbal connected to the arm side of the wire to prevent movement of the arm in six degrees of freedom and interference with the wire suspending the arm, and the multi-jointed arm is bent. The joints on both sides of this multi-jointed arm are in a wire hanging position, and a gimbal is attached at the intersection of the bending axis of the bending joint and the rotation axis of the adjacent rotary joint. A constant-tension suspension mechanism is provided at the rotating and bending parts of the arm, with counter balancers that fix the center of gravity of the joint at the center of the gimbal against rotational movement at the rotational joint and bending movement at the bending joint. provided.

Further, in the present invention, as a fifth embodiment, the above-mentioned first
- Any one of the fourth embodiments of the constant tension suspension mechanism further includes an angle sensor 107 that detects the inclination of the wire 102, and feeds back the wire inclination angle detected by the angle sensor 107 to the suspension position moving mechanism section 106 to adjust the wire. A constant tension suspension mechanism is provided that is configured to control the wire suspension position such that the wire is oriented vertically.

Further, in the present invention, as a sixth embodiment, the above-mentioned first
- In any of the fifth embodiments of the constant tension suspension mechanism, the constant tension applied to the wire 102 is set to a magnitude that cancels the gravity of the target object, so that the behavior of the target object in a zero gravity environment can be simulated. A constant tension suspension mechanism is provided.

In addition, the present invention includes a winding drum having a spiral groove having a diameter larger than the diameter of the wire for suspending the object on its outer circumferential surface, a spline that provides freedom of movement in the direction of the rotational axis of the winding drum, and A wire used in a hanging mechanism comprising a guide roller that has a protrusion that engages with a groove of the winding drum and is rotated as the winding drum rotates and guides the winding drum in the direction of its rotation axis, and a motor that rotationally drives the winding drum. A winding mechanism is provided.

In addition, in the present invention, two rollers are arranged on the base body and guide the wire vertically downward to hang the target object, and the wire guided by the rollers is placed at a different level in the vertical direction from these rollers so that the wire receives the horizontal component of the tension. an uneven roller disposed between two rollers, a plate spring that supports the uneven roller on a base and is distorted according to the horizontal component of the tension, and a strainer that is attached to the plate spring and detects the amount of distortion of the plate spring. A tension sensor for use in a suspension mechanism comprising a gauge is provided.

Furthermore, in the present invention, the first and second axes, and the second and third axes, which are adjacent to each other outward from the center, are orthogonal to each other, and the third axis is a vertical axis that rotates due to the twisting of the wire itself. With this configuration, a gimbal for use in a suspension mechanism having a three-axis rotation mechanism is provided.

[Operation] In the first form, the wire 1 for hanging the target object 101
The tension sensor 103 detects the tension applied to the wire 102, and the control unit 105 causes the winding mechanism unit 104 to wind the wire 102 and unwind it seven times so that the tension becomes a constant value. Also,
The hanging position of the wire is moved by the hanging position moving mechanism so that the wire 102 is always vertical (vertical) so that a horizontal component of tension does not occur.

In the second form, a multi-joint structure is used as the target object 101, several parts of this multi-joint structure are suspended with constant tension using wires, and a horizontal multi-joint type suspension is used as the suspension position moving mechanism section 106. An arm is used to move the wire hanging position to simulate a zero gravity state.

In the third embodiment, a suspension arm is connected to a support drive unit that supports and drives the multi-joint structure base, thereby simplifying and rationalizing the control operation.

In the fourth embodiment, the gimbal prevents interference between the movement of the arm of the multi-joint structure and the suspension wire, and the counterbalancer optimizes the suspension position of the arm of the multi-joint structure.

In the fifth embodiment, the angle sensor 107 detects the inclination of the wire 102, and the inclination of the wire 102 is detected by the hanging position moving mechanism section 10.
6, the vertical retention of the wire 102 is improved.

In the sixth embodiment, the tension value of the wire 102 is set to a value that cancels the gravity of the target object 101, thereby making the target object in a simulated weightless state.

In the winding mechanism for the wire 102, the winding drum is rotated by a motor to wind and unwind the wire seven times. At this time, the spline gives the winding drum a degree of freedom of movement in the direction of the rotational axis, and the guide roller guides the rotational shaft direction to the right/left at a further pitch according to the winding and unwinding rotations of the winding drum. The wire is spirally wound in a single layer along a groove cut on the outer peripheral surface of the winding drum.

In the tension sensor, the uneven roller receives the horizontal component of the tension applied to the wire, the leaf spring is distorted by this horizontal component, and the amount of strain is measured with a strain gauge to obtain the horizontal component force. The tension is calculated from the component forces.

In the gimbal, by using a wire as the third axis, we utilize the twistable nature of this wire to ensure rotational freedom around the third axis, thereby simplifying the configuration. There is.

(Margin below) [Example] Embodiments of the invention will be described below with reference to the drawings.

1. Basic methods of zero-gravity simulation system Here we will discuss four basic methods.

1.1. Offline Zero Gravity Simulation Experiment System 1 The Bokuto type is an offline zero gravity simulation system using a constant tension suspension mechanism and a support drive mechanism using a robot. In this method, before directly moving a multi-joint structure (such as a space robot), the movement of the multi-joint structure in response to an external force under zero gravity is calculated in advance using special software. The system uses a hardware mechanism to realize exactly the same movement of a multi-joint structure on the ground based on the movement that has been confirmed through calculations.

i, i, 1. Overall Configuration The overall processing outline of the weightless simulation experiment system for realizing the present method is shown in FIG. The system as a whole consists of a simulation data creation section 1, a zero-gravity simulator 2, and a multi-joint structure 3. It is configured to be driven via a control section 21.31 using a value calculated in advance by a software section (motion analysis software section) 12. Further, the overall hardware concept corresponding to FIG. 2 is shown in FIG.

Further, a perspective view of the specific hardware configuration of the entire mechanical section of this zero-gravity simulation system is shown in FIG. 4, a top view thereof in FIG. 5, and a side view thereof in FIG. 6.

Hereinafter, the configurations of the simulation data creation unit 1, the zero-gravity simulator 2, and the multi-joint structure 3 will be explained based on these figures.

a. Simulation data creation unit The simulation data creation unit 1 includes a zero gravity simulator 2
and a part that creates basic data for operating the hardware mechanism of the multi-joint structure 3. This part consists of a multi-joint structure mathematical model section 11 that defines a mathematical model of the multi-joint structure 3, and a motion analysis software section that analyzes the movement of the multi-joint structure 3 defined by the multi-joint structure numerical model 11. 1
2, a simulation display software section 13 that graphically displays the output results of the motion analysis software section 12, and a data software conversion software section for zero gravity simulator that converts and processes the output results of the motion analysis software section 12 for the zero gravity simulator 2. Consisting of 14.

b. Multi-joint structure (space robot) The multi-joint structure 3 consists of a multi-joint structure control section 31 and a multi-joint structure mechanism section (robot main body) 32.
constitutes a servo mechanism that uses the data created by the data conversion software section 14 as a follow-up target value. Robot body 32
As shown in FIG. 4, there are two left and right multi-jointed arms 303 each with six degrees of freedom, and a hand 3 attached to the tip of the arm.
04, it consists of a book 305 that fixes this multi-joint arm 303, and a hand 304 performs operations such as capturing an object. The multi-joint arm 303 is designed to be lightweight in consideration of ease of transportation to space, and is a flexible arm with elongated links 200 to 300 mm in length and with reduced rigidity against bending and dust. Total arm length is approximately 1400m
It is m. In addition, in order to extend the lifespan in space, the DD arm has a structure in which a direct drive (hereinafter abbreviated as DD) motor and encoder, which have no transmission parts and can reduce contact parts, are directly connected to the joints. FIG. 7 shows the joint configuration of the arm. In the figure, θ2 θ3 and θ5 marked with ■ are bending axes, and 01, θ4 and θ6 marked Φ are rotation axes. The zero-gravity simulation system thus simulates the complex behavior of a robot mechanism having a multi-joint arm 303 using flexible links and DD motors.

C1 Zero gravity simulating device The zero gravity simulating device 2 is divided into a zero gravity simulating control section 21 and a zero gravity simulating mechanism section 22, and the control section 21 constitutes a servo mechanism that uses data created by the data conversion software section 14 as a tracking target value. .

The zero-gravity simulation mechanism section 22 includes a main body support drive section 202 consisting of a 6-degree-of-freedom robot mechanism section 208 that supports and drives the main body 305 of the target multi-joint structure 3 with 6 degrees of freedom, and parts other than the target base 301. and a constant-tension suspension mechanism section 201 that suspends it by a wire 210. The multi-joint structure 3 includes a base portion 301 and other arms, panels,
It consists of a portion 302 such as an antenna. At this time, the base 301 of the multi-joint structure 3 is supported by a six-degree-of-freedom robot mechanism 208, and the other parts 302 are supported by a plurality of sets of constant-tension suspension mechanisms 201. The entire weightless simulator consists of a frame 203 installed to surround the entire mechanism.
Supported by

In the zero-gravity simulating mechanism section 22, when the entire robot body 32 is supported by wires 210 suspended vertically downward, the number of wires increases and the mechanism and control become complicated. Therefore, the load on the suspension mechanism by the wire 210 is limited to the arm portion 303 as shown in FIG. 4, and this is referred to as a constant tension suspension mechanism section 201. The wire 210 is moved in the vertical direction under constant tension control using the hanging mechanism section 201 to balance the tension of the wire 210 with the gravity of the arm 303 and cancel the gravity of the arm 303.

The main portion 301 of the robot body 32 is supported by the robot mechanism section 208 with six degrees of freedom, and the entire suspension mechanism is supported and driven with two degrees of freedom in the horizontal plane. This is the main body support drive section 20
It is called 2. The movement of the wire 210 in a direction other than the vertical direction (the movement of the suspension mechanism section 201 in the horizontal plane, the movement of the robot main body 32, and the main body support drive section 202) is performed according to the calculation results of the simulation software.

1.1.2 Elemental Parts The main elemental parts used in this zero-gravity simulation system are explained below.

a. Constant tension suspension mechanism The constant tension suspension mechanism section 201 includes a horizontal articulated two-degree-of-freedom robot mechanism (hanging arm) 204 that moves the hanging positions of multiple wires in a horizontal plane, and this hanging arm 204. A wire winding mechanism 205 is mounted on the wire winding mechanism 205 and includes a winding drum that winds and unwinds each of a plurality of wires, a winding drum rotation drive unit, etc., and a wire 210 that is mounted on an extension of this winding mechanism 205 and hangs the arm 3O2. It consists of a tension sensor 206 that measures the tension of the wire 210 to cancel gravity, and a gimbal 207 that is connected to the arm 302 side of the wire 210 and prevents interference between the six degrees of freedom movement of the arm 302 and the wire 210. . Next, the details of the suspension mechanism section 202 will be explained by dividing it into a vertical movement mechanism that cancels gravity with the wire 210, and a movement mechanism that moves the hanging position in a horizontal plane according to the movement of the suspended arm 302. do.

(2) Vertical movement mechanism After explaining the suspension tension adjustment method, which is the key point of the zero-gravity simulating mechanism section 22, we will explain the suspension position, gimbal 207, and counter, which are the component technologies of the constant tension suspension mechanism section 201 adopted in this example. Balancer 220, winding mechanism section 2
05, the tension sensor 206 will be sequentially described.

(B) Suspension tension adjustment method Various methods can be considered as a suspension tension adjustment method that suspends the arm 302 to simulate zero gravity. For example, as shown in FIG. Counterbalance type, suspended by a counterbalancer, the wire with the arm suspended using a spring is wound onto the wire winding drum/
There are constant force spring type (Conston spring) that pays out, and winding type that suspends the arm using a wire winding drum and winding motor.

Among these, the winding type consists of a wire winding drum, a motor that drives the winding drum, and a wire tension sensor.The output of the tension sensor is fed back to the motor and the tension is kept constant through winding and unwinding operations, simulating zero gravity. It is something. This winding method is advantageous in that it can easily respond to changes in hanging weight and can aim for compactness and high precision, and this winding method is adopted in the present invention.

FIG. 9 shows how to deal with the vertical vibration component of the flexible link. The spring winding type [A] is a method that absorbs vibrations using a coil spring that is one order of magnitude lower than the natural frequency of the flexible link.
The winding method [B] is a method in which the band of the winding system is made one order of magnitude higher than the natural frequency of the flexible link, and winding is performed in accordance with the vibration. The winding type has the advantage that weightlessness can be simulated by winding and unwinding the wire with constant tension control even in response to the vertical vibration input of the arm of an arbitrary profile, and this example adopts this method. There is.

(b) Referring to FIG. 7 showing the hanging position, gimbal, and joint configuration of the counter balancer arm 303, the mass of the arm 303 is the (θ, +02) axis, the (θ3+04) axis,
(θ, +06) It is concentrated at three joints of the axis.

When the attitude of the arm 303 changes, the distribution state of the mass at the three locations changes. It is desirable that this arm 303 can be supported by as few wires 210 as possible.

On the other hand, in the case of a flexible link, if the link portion is hung intensively, the flexible link will bend due to tension, and the behavior of the arm 303 will be affected by the suspension. Therefore, in this example, in FIG. 10 schematically showing the arm, (θ3+04)
The shaft and the (θ, 106) shaft are suspended by wires 210 at two locations. In FIG. 10, O1 represents the rotation/bending axis,
Among these, R is a rotor, and S is a stator. Note that (θ1
102) The shaft is supported by the book 305, and the main body support drive unit 20
Driven by 2.

Furthermore, when performing a mechanical analysis of the suspension method for a single flexible link with mass points at both ends, it was found that even if the link's posture changes or bending vibration occurs, by hanging both ends with a constant tension, weightlessness can be approximated. An example of conditions that can be simulated is revealed. This condition is that the mass at both ends is sufficiently larger than the link mass, and the linear density of the link is sufficiently high. Arm 3 of this embodiment
The structure and hanging method of 03 are adapted to these conditions.

If one wire 210 is hung at each location other than the center of gravity, a moment will be generated due to the distance to the center of gravity and gravity, and the behavior of the arm will be affected by gravity.

To prevent this, the centers of gravity of the (θ3+04) and (θ5+06) axes are each suspended by one wire 210. However, since each center of gravity is inside the joint, one point is connected to the wire 21.
It cannot be measured directly at 0. Therefore, a gimbal 207 shown in FIG. 11 is used for indirect support from the outside. This gimbal 207 is a connecting member so that the ψ2 axis, the ψa axis, the ψ1 axis, and the ψ8 axis, which are adjacent to each other outward from the center, that is, the center of gravity, are orthogonal to each other, and the orthogonal intersection points coincide with the center of gravity of the suspended object. It is a mechanism that rotatably supports objects by connecting them. This gimbal 207 has ψ axis,
Ball bearings are used for the ψ2 axis to provide rotational freedom, and the ψ8 axis is substituted with the freedom of the dust of the wire itself, simplifying the structure.

Furthermore, as mentioned above, even if the joint angle changes, the center of gravity of the suspended object must be fixed at one point at the center of the gimbal. For example, in order to fix the center of gravity of the (θ3+04) axis in FIG. 10, the following sufficient conditions are required for the centers of gravity of the three members S3, (R3+34), and R4.

■Since the center of gravity of the entire (θ3+04) axis does not change even if the θ4 axis is rotated, the center of gravity of R4 is on the 04 rotation axis.

■Since the center of gravity of the entire (θ3+04) axis does not change even with θ3-axis bending, the composite center of gravity of (R4+S4 +R3) and 83
The centers of gravity of both are θ, which is on the intersection of the bending axis and the 04 rotation axis.

■Hang the intersection with a gimbal. In order to realize (1) and (2), counter balancers are provided on the rotating shaft and the bending shaft as shown in FIG. FIG. 12 is an example for the (θ3-04) axis, and in FIG. 12, 220a is the counter balancer of the half-length portion 220A of the (θ4-05) link;
0b is the half length part 220B of the link between (θ2-03)
220c is a counter balancer for 220C, 220e is a counter balancer for setting the center of gravity of the fourth axis rotor R4 on the 04 axis, and the bending axis θ3 is composed of the third axis rotor R3 and stator S3, Rotation axis θ
4 consists of a fourth shaft rotor R4 and stator S3.

A counter balancer is similarly provided on the (θ5+06) axis at the tip of the arm. The intersection of two adjacent axes is on the bending axis as shown in FIG. This is also advantageous in the following respects.

■The rotor shaft can be shared with the gimbal connecting member, simplifying the mechanism.

■There is less interference between the counter balancer and gimbal, allowing for a wider operating range.

■The hanging position can be easily calculated using control and simulation software.

(C) Wire Winding Mechanism The winding mechanism 205 needs to wind the wire around the winding drum many times in response to the vertical movement of the arm. In this case, if the winding drum is simply driven to rotate around the winding drum axis, the wires will overlap in one place on the winding drum and wind up like a mountain. If the wires slip and the mountain collapses, the operation will become discontinuous and unstable. The wire is also easily cut.Therefore, the wire must be wound in a single layer on the winding drum at pitches that do not touch each other.A winding mechanism for this purpose is shown in FIG.

FIG. 13 is a front view of the winding mechanism section 205 including a tension sensor 206, which will be described later. FIG. 14 is a side view of this as seen from six directions, and FIG. 15 is a top view of this as seen from direction B. .

In the figure, 230 is a DC motor with a reducer, 240 is a motor mounting plate, 231 is a shaft coupling that transmits the rotation of the motor 230 to the ball spline 232, and 241 is the ball spline 2.
32 is a support bearing, 232 is a ball spline that rotates the winding drum 235 with the rotation shaft of the motor 230 and provides a degree of freedom of movement in the direction of the rotational axis of the winding drum, 233 is a ball spline nut, 234 is a ball spline shaft, 235 236 is a bearing mounting plate; 237 is a guide roller with a protrusion that regulates the axial movement of the winding cylinder 236; 238 is a guide roller support shaft; 239
is a guide roller bearing.

The winding drum 235 is provided with a spiral groove 1.5 times the diameter of the wire 210. A ball spline 232 is attached to the inside of the winding drum 235, and the winding drum 235 is rotationally driven by a motor 230 to provide a degree of freedom of movement in the axial direction of the winding drum 235. A guide roller 237 having a protrusion that engages with a groove in the winding drum 235 is fixed to the frame of the winding mechanism section 205. As a result, the winding drum 235 rotates and is guided by the guide roller 237 that engages with its groove, and moves to the right/left in the axial direction in accordance with the winding and unwinding of the winding 7, and therefore the winding position of the wire 210. The wire can be spirally wound in a single layer in the groove of the winding drum 235 while the wire remains fixed.

(d) Structure of Tension Sensor and Control Device There are various methods for detecting the tension applied to the wire 210, such as those shown in FIG. 16, for example. In other words, the current sensor method detects the motor current and calculates the motor output torque (Fig. 2A), the torque sensor method attaches a torque sensor to the output shaft of the reducer (Fig. 2B), and the load cell is installed in the middle of the wire. These include the load cell method (Fig. 2C), which detects the load with a wire guide, and the strain gauge method (Fig. 2D), which uses a strain gauge attached to the wire guide bobbin support.

In this example, among these wire tension detection methods,
A strain gauge method is used, which has the advantage of being able to measure tension stably. As for the structure, a first
As shown in FIG. 3 and FIG. 17, two rollers 250, 251 are provided vertically below the wire winding position, and between them there is a A third roller 252 having a support shaft at a different level is provided. This uneven roller 252 is supported by a leaf spring 253, and the four strain gauges 254 are handled by the spring 253.
to obtain differential output.

With this configuration, the wire 210 is connected to the uneven roller 2.
If you wrap it around 52 and hang it, this uneven roller 25
2 can create a horizontal component of tension, and this horizontal component P can be found as follows: T=P/2sin θ, where T is the tension and θ is the angle that the wire 210 makes with the vertical line. The amount of strain of the parallel plate spring 253 that supports the uneven roller 252 is equal to the horizontal component force P within the range of elastic deformation.
Therefore, the tension T of the wire can be detected by detecting the amount of strain with four strain gauges 254 attached to the parallel plate spring 253, two on the front and the back.

The output of this tension sensor generated by the gravity of the arm joint is transmitted to the rotational drive motor 23 of the wire winding mechanism section 205.
By feeding back to 0, winding and unwinding operations with constant tension control can be obtained.

b. Movement mechanism in the horizontal plane (hanging arm) The wires of the two arms are moved two-dimensionally in accordance with the movement of the arms in the horizontal plane that projects the hanging position. The bending axis and the adjacent linear axis are one unit of the joint configuration, and these are connected in multiple stages to form a horizontal multi-joint type joint configuration.

Specifically, as shown in FIG. 18, each arm is a hanging arm having four degrees of freedom: two straight axes and two bending axes. The next bending axis φ2 is mounted on the table of the straight axis dzl. Also, the linear axes d g + and dl
The aforementioned winding mechanism section 205 is mounted on the table. When the arm rises vertically downward, the two tables are moved closer to each other to reduce the distance between the wires and follow the movement of the arm. The entire hanging arm 201 is connected to a book support drive section 202, which will be described later, by a shaft. When the main body support driving unit 202 moves the book 301 in a straight line or in rotation in a horizontal plane, the entire hanging arm also moves parallel to the arm in a horizontal plane. The main body support drive section 202 is the base 30
1 in the vertical direction, the hanging arm 201 does not move and maintains a constant height.

A DC motor with a speed reducer is used for bending the hanging arm 201, and a DC motor, a ball screw, and a straight guide are used for straight movement. The motion is detected using an optical rotary encoder and the motor is servo controlled.

■0 book support drive unit etc. The main body support drive unit 202 is a device that moves the book 301 to take any position and posture, and is a robot mechanism with 6 degrees of freedom (d ax, d 8Y, de□, α, β
, γ). As shown in FIG. 210, the three degrees of freedom for position are assumed to be a Cartesian coordinate robot with dex, dB, d, and □ axes.

In the dllY and dB□ axes, the table moves straight in a horizontal plane on an axis with both ends fixed, whereas in the dex axis, the axis passes through the fixed table and moves straight in the vertical direction.

Regarding posture, there are three degrees of freedom a, rotation and bending, which are orthogonal to each other.
, β, and γ axes are arranged in series. The α-axis is mounted on the day-axis table and the entire d-axis is rotated. α axis and dex
Connect the φ1 shaft of the hanging arm between the shafts. The drive mechanism uses a motor, ball screw, and linear guide for linear movement. Since the travel distance for all three linear axes is long, the critical speed decreases when the ball screw shaft rotates, and vibration and noise are likely to occur. To prevent this, ball screws are used by fixing the screw shaft and rotating it with a nut. A motor with a speed reducer is used for rotation and bending operations.

In particular, on the α-axis, the robot body and hanging arm must be rotated in synchronization, resulting in a large rotation mechanism. d The entire table of the sx axis is surrounded by large gears, and the output of the motor with a reduction gear is transmitted to this using small gears. This makes the rotation axis of a coincide with dex, making the mechanism simple even if it is large. Motion detection is performed using an optical rotary encoder, and the motor is servo controlled.

Although the main body support drive section 202, the suspension mechanism 201, and the robot main body 32 are large and heavy, it is necessary to obtain high positioning reproducibility. Therefore, the straight guide is attached to the gate-shaped frame 203 which has high rigidity and can provide stable accuracy over the entire operating range. The ball screw shaft is also fixed to this frame 203, and the frame 20
It becomes a structure that reinforces 3. In addition, the hanging arm part 201
The arm portion 302 has a cantilever structure. If the tip thereof is made to protrude outside the frame 203, the operating range of the α and d8□ axes will be increased. Therefore, the hanging arm part 201 and the arm part 302
is operable until it passes through the crossbeam of the frame and protrudes.

FIG. 20 shows the degree of freedom configuration of the entire mechanical section. As shown in the figure, the zero-gravity simulating mechanism section 22 is a six-degree-of-freedom robot mechanism section (d8X,
dBY, d8z, α, β, γ) and four sets of constant tension suspension mechanisms 201. The four wires 210 are two arms with four degrees of freedom extending horizontally ([φ81, ds*+φ8□
, dg*2] [φL1, d9LI% φL2, dst
, 2]), and a robot mechanism with two degrees of freedom per wire book corresponds to the account. The degrees of freedom of the parts driven by the motor are 12 for the robot main body 32, 12 for the suspension mechanism section 201, and 6 for the main body support drive section 202, for a total of 30 degrees of freedom.

1.1.3. Offline data creation method A method for creating offline data based on this embodiment will be described.

A model corresponding to the robot body 32 shown in FIG. 20 is constructed in the multi-joint structure mathematical model ll. When constructing a model, it is necessary to specify the overall joint configuration, link length, mass of each link and joint, moment of inertia, and center of gravity position.

The motion analysis software 12 calculates time series of joint angles, joint angular velocities, three-dimensional coordinate values of the suspension position viewed from the inertial system, and their velocities, etc. of the defined mathematical model. FIG. 21 shows the input and output to this motion analysis software. As shown in the figure, the input is a mathematical model of a multi-jointed structure, which includes ■the overall joint configuration, ■the length of each link, ■the mass and moment of inertia of each link and joint, and ■the position of the center of gravity of each link and joint. , In addition, as the initial values of the multi-jointed structure, ■ initial values of the main center of gravity position and posture angle, ■ initial values of the differential of the main center of gravity position and differential of the posture angle, ■ initial values of each joint angle and its derivative, ■ multi-joint This is a time series of torque. In addition, the output time series is: ■ Time series of main center of gravity position, attitude angle, and their derivatives,
■Time series of each joint angle and its derivative; ■Time series of coordinate values of multi-joint structure sensor points and their derivatives.

The simulation display software 13 displays the output results in graphs, calculates the maximum and minimum values, automatically checks whether the calculated values are within the valid range, and avoids calculating values that are outside the valid range. In such cases, the user is notified of this in the form of a warning.

The zero-gravity simulator data conversion software 14 converts the time series of the position and posture of the center of gravity of the book 301 of the multi-jointed structure 3 calculated by the motion analysis software 12 into the six-degree-of-freedom robot mechanism section (a SX, d,Y,d,,,α,
β, γ) is converted into a time series, and the four wires 210
The three-dimensional time series of the hanging position and speed for the two hanging arms ([φR2, d 9R1φ−□, dsRz ]
[φLl dst+φL2, DgL2]) is converted into a time series of each joint angle and angular velocity. The joint angle data for the two hanging arms are created so that the wire 210 always remains vertical, following the movement of the multi-joint structure 3.

Specifically, the four hanging points (T11., T3□, TR3, T, I4) of the hanging mechanism 201 are reversed so that they are on the vertical line of each hanging position (OR3, OR5, θL3, θL6). Solving kinematics.

1.1.4 Based on offline data (cooperative control operation 2nd
FIG. 2 is a diagram cut out from FIG. 2 with a focus on the control system in particular. As shown in the figure, each control unit 21.31 has the functions of communication control, command interpretation/selection, and servo control.
Synchronous control is performed by communication such as PIO (parallel input/output).

The joint angle data time series of the multi-joint structure 3 and the zero-gravity simulator 2 created based on the offline data creation method described above are stored on the memory of the control unit 31.21 in FIG. The two control units 31.21 each have a PI
Servo follow-up control is performed on each mechanism section 32.22 using the stored data as a target value while taking timing through communication such as O. Each mechanism part 32.22 cooperates under the control of the control part 31.21 to extend the suspension wire 210.
It works to keep it vertical. As shown in Figure 22,
This system can be said to be a servo mechanism that maintains the hanging wire vertically in a feedforward manner using data calculated by the motion analysis software 12 and data conversion software 14 for zero gravity simulator as target values.

Also, the wire winding mechanism 20 of the constant tension hanging mechanism section 201
5, to cancel the gravity of the wire 302 and realize a simulated weightless state, the wire 210 is wound and unwound seven times to keep the tension applied to the wire 210 constant.

■、2. Off-line zero-gravity simulation system ■This method is an offline zero-gravity experimental system that uses a constant tension suspension method and support drive by a robot, and improves the followability of the suspension arm by providing a feedback loop using an angle detection sensor. .

The offline zero-gravity simulation system I described above consists of a multi-joint structure 3, a two-degree-of-freedom robot mechanism section 204.6, and a multi-joint structure 3.
This is a method in which the degree-of-freedom robot mechanism section 208 is servo controlled. In this method, the target trajectory for servo control is created based on a software model built on a software simulator, so if the model is inaccurate, it may cause the wire 210 to tilt, and complete gravity compensation may not be possible. It may be damaged. In order to compensate for this, the method proposed here attaches an angle detection sensor to the root part that supports each wire 2]0, and the inclination of the wire 210 detected by this sensor is detected by the two-degree-of-freedom robot mechanism that suspends the wire 210. 204 to perform local position control and improve vertical retention of the wire 210.

1.2.1. Overall configuration FIG. 23 shows a processing outline of the off-line zero gravity simulation experiment system H. The difference from the above-mentioned system I is that the zero gravity simulation control section 21 is provided with an angle detection sensor and local feedback control is inserted.

1.2.2. Elemental parts We will explain the new elemental parts used in this offline zero-gravity simulation system ■.

a. Angle detection sensor Two examples of angle detection sensors that detect the inclination of the hanging wire 210 will be described: an optical angle detection sensor and a component force detection sensor.

(2) Optical angle detection sensor FIG. 24 explains the principle of the optical angle detection sensor. As shown in the figure, a gimbal 207 that rotatably holds an arm 302 is suspended by a wire 210, and the gimbal 207 is suspended by a wire 210.
A ball bearing is provided on the wire 210 so that the rotation of the gimbal is not transmitted to the wire 210. Wire 2 for hanging gimbal 207
A light emitting body 331 such as an LED is arranged at the mounting position 10 as close as possible to that position. The wire 210 is attached to the hanging arm side by a two-dimensional photoreceptor 332, such as a CCD or PSD, for detecting the position of the light emitter 331.
(position detection device) or a camera, etc.

Now, with the wire 210 hanging vertically, the position (δ8o, δ) of the light emitter 331 detected as a two-dimensional screen by the photoreceptor 332 is expressed as the XY of the two-dimensional screen.
Set as the origin of coordinates. If the position of the light emitter 331 in the two-dimensional screen detected by the photoreceptor 332 when the wire 21O is tilted from the vertical direction is (δ8, ay), then the wire 2
10 deviation from the vertical line, that is, the angle △θ with the vertical line
is determined by Δθ==sin−'(δ/h)#δ/hδ=“7 bows=death”. Note that h in the above formula is the length of the wire 210.

(1) 1-Component Force Detection Sensor The principle of a component force detection sensor that detects the inclination of a hanging wire using a horizontal component force is shown in FIG. 25, and a more specific example of its configuration is shown in FIG. 26. As shown in the figure, this component force detection sensor 340 is attached to the lower part of the tension sensor mechanism 206, and includes a ball bearing portion 342 through which the wire 210 passes;
A 6-degree-of-freedom sensor (or a 2-degree-of-freedom sensor) that detects the deviation of this ball bearing 342 in the horizontal plane
341, a cover 343 surrounding the component force detection sensor, and the like. Note that the six-degree-of-freedom sensor 341 is fixed to the base of the tension sensor mechanism 206.

With such a configuration, when the wire 210 is tilted from the vertical direction, the wire 210 causes the ball bearing portion 342 to be displaced in the horizontal direction, and the magnitude of the displacement is detected by the six-degree-of-freedom force sensor 341. , whereby the inclination Δθ of the wire 210 from the vertical line can be measured. For example, if the horizontal component force detected by the force sensor 341 is Tc, then the slope is Δθ8 = sin-' (Tc /T)T. :
T, , "+T-7. Here, T is the bow length force applied to the wire 210, and T
cx and T ay are X of the component force Tc in the horizontal plane
direction and the X direction component.

When detecting the inclination Δθ of the wire 210 using such a component force detection sensor 340, accurate measurement can be performed without being affected by the rotation of the gimbal 207 or the twisting of the wire 210.

1.2.3. Control operation The basic control operation of the offline zero-gravity simulation system■ is the same as the offline zero-gravity experiment system.
The difference is that when the wire 210 has an inclination of 80, the angle detection sensor detects the inclination △O and feeds this back to the two-degree-of-freedom robot mechanism 204 so that the wire 210 returns to its original vertical direction. The wire hanging position is controlled.

1.3. The online zero-gravity simulation system 1 is a wooden sword system that uses a compromise between a constant tension suspension system, an angle sensor to hold the suspension direction vertically, and a support drive using a robot.

1.3.1. Overall configuration FIG. 27 shows a processing outline of the online zero gravity simulation experiment system I.

This method separates the software simulation section and the hardware simulation section, and uses the values detected by the angle detection sensor and the 6-degree-of-freedom sensor that detects the force and moment exerted on the base of the multi-jointed structure to create a zero-gravity simulator 2. It is characterized by a feedback control system that corrects each joint angle in real time.

That is, the zero-gravity simulation control unit 26 has a sensor for detecting the angle of the hanging wire 210 and a 6-degree-of-freedom force sensor that detects the reaction (force and moment) acting on the multi-joint structure base 301, and the multi-joint structure control unit 36 has A joystick 35 for controlling the multi-joint structure is connected.

1.3.2. Element Part a: Robot-based Reaction Detection Mechanism FIG. 28 shows a reaction detection mechanism that detects the reaction acting on the base 301 of the multi-joint structure 3 as the joints of the multi-joint structure 3 are driven. As shown in the figure, when attaching the two left and right arms 302 to the base, a six-degree-of-freedom sensor 351 is attached to the base, and the six-degree-of-freedom sensor 351 is attached to a cover 352.
It is surrounded by This six-degree-of-freedom sensor 351 can detect the reaction (force and moment) acting on the base 301.

1.3.3. Control Operation The basic processing flow of this method will be explained based on FIG. 27.

In the system ■ shown in FIG. 2, the entire system is driven offline based on data prepared in advance, but in this system, it is possible to drive the multi-joint structure 3 in real time using the joystick 35. be. The multi-joint structure control section 36 is a servo mechanism that uses a command value from the joystick 35 as a target value, and can remotely operate the multi-joint structure mechanism section 32.

The multi-jointed structure 3 changes its base 3C as the joints are driven.
1 is subjected to a reaction (force and moment), and the suspension wire 210 is displaced from the vertical line.

The zero-gravity simulation control unit 26 detects this reaction with the 6-degree-of-freedom force sensor 351, and uses this value in the mechanics calculation unit to calculate the 6-degree-of-freedom robot mechanism [a, x, ciBY, dB□, α, β
, γ] (see FIG. 20) into the next step command value for each joint angle. 6 degrees of freedom robot mechanism [dBX
, daY, daz, a, β, γ], the servo drive is repeated one after another using the calculated next step command value as the target value.

FIG. 29 shows an algorithm for causing the base 301 of the space robot 3 to move in the same way as in zero gravity space using the detected value of the force sensor 351. As shown in the figure, the output values (force and moment) of the left and right 6-degree-of-freedom force sensors 351 are detected (step S1), and from Newton's equation and Euler's equation for the base 301 of the space robot, the base center of gravity position of the next step is determined. Calculate the time derivative of the attitude angle (Step S2), and 6 degrees of freedom robot (
dX, dv, dez, a, β, γ) is calculated (Step S3), the 6-degree-of-freedom robot mechanism is servo driven (Step S4), and this process is repeated.

Similarly, the deviation of the hanging wire from the vertical line is detected by the angle detection sensor of the zero-gravity simulation control unit 25, and the hanging arm (two-degree-of-freedom robot mechanism) 204 is servo-driven so as to always correct this deviation to zero.

With the control method described above, the base 301 of the multi-joint structure 32 always behaves in a way that takes into account the influence of reaction.
The hanging arm 204 moves following the multi-joint structure 3 so that the wire 210 always remains vertical. This control system has real-time properties on a time scale longer than the time required for the dynamic calculations of the zero-gravity simulation control section 26 and the sampling time of the servo drive.

This online zero-gravity simulation system (■) also makes it possible to display hardware-based zero-gravity simulation experiments using software. That is, the initial value and drive command value of the multi-joint structure 3 are directly sent to the motion analysis software 12 of the real-time software simulator 10 through the joystick 35. The kinematic analysis software 12 substitutes the obtained values into the equation of motion and displays them on the simulation display software 13 for each step. With this method, real-time response is possible to movements on a time scale longer than the basic step interval in the movement analysis section 12 and display section 13.

As mentioned above, in this system configuration, joystick 35
It is possible to check the behavior of both hardware and software in real time based on the command values.

1.4. Online Zero Gravity Simulation Experiment System ■This method uses only a constant tension suspension method and a method of holding the suspension direction vertically using an angle sensor.

1.4.1. overall structure FIG. 30 shows an outline of the processing according to this method.

The feature of this method is that in the zero-gravity simulation mechanism section 22 of the online zero-gravity simulation experiment system I mentioned above, the center of gravity of the base 301 is suspended instead of the six-degree-of-freedom robot mechanism section that supported the base 301 of the multi-jointed structure 3. A constant tension suspension mechanism is newly provided, and the entire multi-joint structure is suspended by wires 211, as shown in FIG.

Therefore, the zero-gravity simulation control section 27 of this system includes an angle detection sensor, and the mechanism section 22 includes a constant-tension suspension mechanism section that hangs the center of gravity of the base instead of the 6-degree-of-freedom robot mechanism section. The rationale for setting the hanging position on the center of gravity of the base will be explained in detail in the next section.

1.4.2. Control operation In this method, the entire multi-joint structure is suspended by multiple wires 210 and 211 with a constant tension, and each suspension arm constantly holds the wire vertically by checking the value detected by the angle detection sensor. The influence of gravity is canceled with respect to any movement of the multi-joint structure 3.

2. Hanging method The basic method for determining the hanging position and tension value of the hanging mechanism, which is one of the important elemental technologies in this zero-gravity simulation system, is described below. A feature of either method is that the influence of gravity on the multi-joint structure can be completely canceled by using a constant tension value that does not depend on the posture.

2.10 Center of Gravity Lifting Above the Vertical Line This method is a constant tension hanging method in which the hanging position is placed on the vertical line of the center of gravity. That is, this method is a method in which the target multi-joint structure 3 is disassembled into links and suspended on a vertical line passing through the center of gravity of each link. The tension value is taken from the weight of each link. In this method, the number of wires is equal to the number of disassembled links. Therefore, when supporting the base 301 of the multi-joint structure 3 using a six-degree-of-freedom robot mechanism, the number of wires is naturally small.

FIG. 32 shows the principle of this system.

In FIG. 32, each link is assumed to be a completely rigid body, and a gimbal mechanism as shown in FIG. 11 is connected to each hanging position P1, P2, and P3. When lifting a single unit, hang the unit on the vertical line of its center of gravity. Tension T is equal to the gravity of a single body. In addition, when suspending a multi-jointed structure, the center of gravity of each unit shall be suspended on the vertical line. Each tension TI, T2, T3 is equal to the gravity of each unit.

As can be seen from Fig. 32, each component is suspended on a vertical line passing through its center of gravity, so the tension values T1 and T2
, T3 are always constant regardless of the posture. The influence of gravity is canceled for each component, so there is no influence of gravity on the entire assembled multi-jointed structure.

2.2. Static balance method This method is a method to determine the suspension position and tension value by establishing a static balance equation for the target multi-jointed structure.

The principle of this system will be explained by taking a serial mechanism as shown in FIG. 33 as an example. Hanging position P1, P of arm 303
2 is the bending axis of each joint, and the hand 304 alone is also 1
Hang with book wire. As mentioned above, a gimbal is used for hanging. It is assumed that the center of gravity of each link can be aligned on a straight line as shown. At this time, the equation of static balance is as follows.

T here. is the tension supported through the left fixed body, T 3 , T2 , T3 are the tensions applied by each hanging wire, and 21 to I26 are the distances from the center of gravity.

From the above formula (5-1), the tension T. ,T,,T,,T.

The value of is calculated as follows.

The balance equation (5-1) is valid for any posture other than that shown in FIG. 33. Therefore, each tension value of +5-2) is constant regardless of the posture of the object.

2.3. Compromise method This method is a compromise between the above-mentioned center-of-gravity vertical suspension method and static balance method in the constant tension suspension method.
This is a method to reduce the number of fishing wires as much as possible.

Now, consider that the entire system shown in FIG. 33 is supported by two wires with tensions T, , and T2. To do this, the hand part that was previously supported by the wire with tension T3 must be supported with wires with tension T, , and T2, but since the center of gravity of link CD has shifted to the right of hanging position C, the wire with tension T3 must be supported. If you remove it, the link CD will sag due to gravity. In order to avoid this, a counter balancer is installed to compensate for the gravity W3 of the link CD, as shown in FIG.

The static balance equation in this case is as follows.

From the above formula (6-1), the tension T. , T, , T2 are calculated. As before, in this case as well, each tension value in equation (6-21) is always constant regardless of the subject's posture, and by hanging with this constant tension, a zero gravity state can be achieved. Can be simulated.

3. Control of hanging arm 3.1. Algorithm for hanging direction vertical holding method The deviation of the hanging wire from the vertical line determined using the angle detection sensor described above is fed back to the position control of the hanging arm by an algorithm as shown in FIG. That is, the sensor output values of the angle detection sensors 330 and 340 (
δ.

δy) (Tc,, T ey) is determined (Step 5
11) Based on this sensor output, calculate the target joint angle of the hanging arm using inverse kinematics regarding the hanging arm.Step 512) Perform servo drive of the hanging arm (
Step 513), repeat this process. The length of the wire is detected from the encoder output value of the winding motor which changes according to the servo drive of the hanging arm (step 514), and this is used when calculating the target joint angle of the hanging arm in the next cycle.

3.21 Constant tension control tension sensor 2 by winding mechanism
06 to detect the tension applied to the hanging wire 210,
A motor control method for controlling the winding motor 230 of the winding mechanism section 205 so that this tension becomes a constant tension will be described below.

3.2.1. Torque Control Method I This torque control method 1 is a method in which the winding motor 230 is torque-controlled based on the detection output of the tension sensor 206, and the tension applied to the hanging wire 210 is kept constant to simulate a zero-gravity environment.

a. Overall configuration FIG. 36 shows a system configuration for realizing the present torque control method (2). As shown in the figure, the system configuration includes a mechanism section 22 of the zero gravity simulating device that is connected with a wire to an object to simulate zero gravity, and a control section 21 that controls this mechanism section.

Here, the zero gravity simulation mechanism part 2 related to this torque control method ■
The components of 2 are the winding mechanism 205 and tension sensor 206 described above in FIG. 13, and in FIG.
A winding motor 230 of the winding mechanism section 205 that lowers the winding, and a tension sensor 2 that detects the tension of the hanging wire 210.
06 is shown. On the other hand, the zero gravity simulation control section 21
A control software 261 that generates a tension value as a tension command value to realize a zero-gravity environment determined by each suspension method in the second section above, and a tension command value of the tension sensor 206 and the tension detected by the tension sensor 206. A control circuit 26 that outputs a torque command value to the winding motor 230 based on
Consists of 0.

b. Structure of each element The specific structure of the winding mechanism section 205 and the tension sensor 206 is the same as that explained with reference to FIG. 13.

C9 How to control the winding mechanism section 205 for simulating zero gravity As mentioned earlier, in order to compensate for the gravity acting on an object and simulate zero gravity, the object is always moved vertically upward by the wire 210 with a tension equal to gravity. Just pull it up. Therefore, the control software 61 outputs the tension value to be applied to the wire 210 as a tension command value to the control circuit 260 in order to cancel the gravity acting on the object and realize a zero gravity environment.

This tension command value can be determined based on the theory described in the suspension method in Section 2 above.

The tension applied to the wire 210 varies depending on the movement of the object and the external force acting on the object. This tension value is determined by the tension sensor 20.
6, and the measured tension value is input to the control circuit 260 together with the tension command value from the control software 261.

In the control circuit 260, the difference between the theoretically determined tension command value and the tension value actually applied to the wire is determined by the comparison section, and this difference is quickly (reduced) by the winding motor 2.
30 is calculated and outputted to the winding motor 230 as a torque command value.

The winding motor 230, which has received the torque command value, winds the wire 2 with the winding drum 235 so as to cancel the tension fluctuation of the wire.
Wind up 10 and unwind 7.

As described above, the tension of the wire 210 suspending the object is kept constant with the gravitational force acting on the object as a target value, thereby realizing a simulated weightless environment for the object.

3.2.2. l-Luke control method ■ This torque control method ■ removes the influence of static friction of the winding motor, etc., and then controls the torque of the winding motor using a tension sensor to keep the tension on the hanging wire at a constant tension. This method simulates a zero gravity environment.

The winding mechanism (winding motor, winding drum) and tension sensor generally have static friction, and when the winding mechanism is suddenly rotated from zero speed, this static friction causes the wire to The winding and unwinding operations are not smooth. As a result, tension control becomes unstable and the simulation of a zero gravity environment becomes inaccurate. This torque control method (2) eliminates the influence of static friction and improves the responsiveness of constant tension control.

a. Overall configuration FIG. 37 shows a system configuration for realizing the present torque control method (2). In this torque control method (2), in addition to the configuration of the torque control method (2) described above, the detected tension value from the tension sensor 206 is also input to the control software 262, and the control software 262 performs control based on this detected tension value. The tension command value to the circuit 260 can be changed.

b. Control method The winding mechanism section 2 corresponds to the movement of the object (space robot).
If a static frictional force is generated when 05 is activated, the tension applied to the wire changes from a constant tension value by the influence of the static frictional force. Therefore, the tension value actually applied to the wire is detected by the tension sensor 206, and the control software 262 detects the tension value actually applied to the wire.
Incorporate into.

The control software 262 compares this actual tension value with its own tension command value. As a result of this comparison, if tension value > tension command value, or tension value < tension command value, it can be determined that the influence of static friction force has occurred, and the tension command value is adjusted to eliminate the influence of static friction. change.

In other words, if the tension command value that is theoretically determined as one that cancels the gravity of the object is set as the reference tension command value, then if the tension value>the reference tension command value, then the tension command value given to the control circuit 260 is set to a certain offset value. Make it smaller. This offset value is determined based on the static friction force that is measured in advance and occurs when the winding mechanism section etc. is activated. Further, when the tension value <the reference tension command value, the tension command value given to the control circuit 260 is increased by the offset value.

In this way, by inputting the tension command value with an offset into the control circuit 260, the output of the comparison section in the control circuit 260 (the difference between the tension value and the tension command value) changes in magnitude by the static friction force. This makes it possible to achieve the effect of eliminating the influence of static friction force.

Specifically, in the control circuit described later, the tension value when gravity and tension are balanced is set as the zero point, so when the tension value is positive, the negative static friction force becomes the tension command in this control circuit. If the tension value is a negative value, the positive static friction force becomes the tension command value.

3.2.3. Torque control method ■ This torque control method eliminates the effects of dynamic friction in addition to the static friction of the winding motor, etc., and then controls the torque of the winding motor using a tension sensor to control the tension on the hanging wire. This method simulates a zero-gravity environment by keeping the weight constant.

In addition to the static friction mentioned above, the winding mechanism (winding motor, winding drum) and tension sensor have dynamic friction that occurs during mechanism operation. This torque control method (■), in addition to eliminating the influence of static friction by the aforementioned torque control method (H),
The effect of this dynamic friction is also removed.

a. Overall configuration FIG. 38 shows a system configuration for realizing the present torque control method (2). In this torque control method (■), in addition to the configuration of the torque control method (■) described above, the winding motor 230
The rotation speed is input to the control software 263, and the control software 263 can change the tension command value based on the tension value from the tension sensor 206 and the rotation speed from the take-up motor 230. .

b. Control method When the winding mechanism unit 205 is performing winding and unwinding, the rotational speed value of the winding motor 230 is controlled by the control software 26.
It will be incorporated into 3. The control software 263 has a function of changing the offset value to be added/subtracted from the reference tension command value explained in the above-mentioned torque control method (2) in accordance with this rotational speed.

Generally, dynamic frictional force is proportional to speed.

Therefore, a proportionality constant that determines the relationship between the rotational speed and the dynamic frictional force generated at that rotational speed is determined in advance through experiments. When the rotation speed is zero, an offset for the static friction force is given to the tension command value as in torque control method ■, but when the rotation speed is not zero, the dynamic friction force is calculated by multiplying the rotation speed by the proportionality constant described above. Calculate and use this as the offset amount of the tension command value. In this case, when the rotation is lowering (rewinding), the tension command value (=dynamic friction force) is a negative value, and when the rotation is winding (winding)
When , it becomes a positive value.

As a result, the output of the comparison section in the control circuit 260 (the difference between the tension value and the tension command value) changes in magnitude by the amount of the dynamic friction force, and together with the effect of the torque control method H described above, the effect of removing the influence of the friction force It is possible to realize this.

3, 2.4. Speed control method This speed control method calculates the speed of the object from the tension detected by the tension sensor and the mass of the target object, and controls the speed of the winding motor based on that value, controlling the tension on the wire to a constant value to create a zero-gravity environment. This is a method of simulating.

a. Overall configuration FIG. 39 shows a system configuration for realizing this speed control method. The difference from the torque control method paths I, 2, and 2 described above is that the zero-gravity simulation control section 21 consists only of control software 264, and this control software 264 obtains the tension value from the tension sensor 264 and sends it to the winding motor 230. It is configured to output a speed command.

b. Control method The feature of this speed control method is that the movement of the object in a weightless environment is calculated directly from the external force F applied to the object, and a speed command is given to the winding motor.

That is, the external force F acting on the object is detected from the variation in the output of the tension sensor 206, and the mass m of the object measured in advance is
Using the following equation, the control software 264 sequentially calculates the velocity V that the object should have in order to simulate a zero gravity environment.

In the formula, Δt is the sampling time, and ■o is the initial velocity. The speed V calculated by this formula is applied to the winding motor 230.
Output as a speed command to. This makes it possible to simulate zero gravity while eliminating the effects of friction on the winding motor 230, winding drum, tension sensor 206, and the like.

3.2. Specific configuration of control circuit Control circuit 26 used in torque control method I, ■, ■ mentioned above
The specific configuration of 0 will be described.

FIG. 40 shows an example of the configuration of this control circuit 260.

As shown, this control circuit 260 controls the winding motor 23.
0 and the tension sensor 206 to form a closed loop and perform constant value control (regulator) with the tension command location as the target location.

In this configuration example, the tension sensor 206 is zero-adjusted in the tension sensor amplifier so that a zero value is given to the control circuit 260 as a tension value when the gravity of the object and the target tension applied to the wire are balanced. . Therefore, the output value from the tension sensor 206 is a fluctuation value from zero (ie, a fluctuation range from the target tension). Correspondingly, the tension command value from the control software 261, 262, 263 is a value that fluctuates from zero when compensating for friction or the like.

As shown in FIG. 40, the control circuit 260
70, an observer 271, a feedback gain adjustment section 272, integrators 273 and 274, and the like. The comparison unit 270 compares the tension value detected by the tension sensor 206 and the tension command value from the control software, and outputs a tension fluctuation value that is the difference between the tension values. The observer 271 is designed based on the transfer function of the winding motor 230 and the tension sensor 206, and estimates the acceleration of the winding motor 230, which is an important state variable, from the tension fluctuation value and the feedback torque command value.

The feedback gain adjustment unit 272
The tension fluctuation value and the estimated acceleration from 1 are also input to integrator 2.
The torque command value is fed back and input from 73, and based on these values, the feedback gain of the torque command value, motor acceleration, and tension fluctuation value is adjusted, and the responsiveness and stability of the entire system are adjusted using modern control theory. It is configured so that it can be adjusted.

The integrator 273 receives the output signal of the feedback gain adjustment section 272, eliminates its steady deviation, and outputs a torque command value.
The torque command value is inputted, and the differential element originally possessed by the controlled object is canceled and applied to the winding motor 230.

4. Simulation calculation system In the zero-gravity simulation experiment system described above, the arm of the space robot is suspended with a constant tension using multiple wires to cancel gravity, thereby simulating a zero-gravity state.

How the base of a space robot moves requires consideration of the reaction of the arm's movement, and it is necessary to generate movement data for the base through calculations while taking this into account. Additionally, the wire that hangs the arm must always be oriented vertically, so the hanging arm must move to follow the movement of the arm.

The amount of calculation required for the operation data of these arms, base portions, hanging arm portions, etc. is extremely large. Furthermore, since such a space robot has a large number of motors that move the base, arm, suspension arm, etc., the amount of calculation required to control them is extremely large. Therefore, a simulation computer system that can efficiently perform these calculations is required.

4.1. System Configuration I System Configuration I is a system configured using a high-performance computer and a plurality of control computers, and is applied to the offline zero-gravity simulation experiment system described above.

This system configuration I is shown in FIG. In the figure, 41
is a high-performance computer such as a workstation, and
This corresponds to the simulation data creation section in the figure.

42.43 is a control computer such as a personal computer suitable for real-time processing, and is a high-performance computer 41.
and R3-232C to exchange data,
The control computers 42 and 43 are connected to each other by a PIO (parallel input/output) channel, making it possible to perform synchronous communication.

The control computer 42 is designed to control the servo mechanisms of the left and right arms of the space robot and the servo mechanisms of the left and right suspension arms of the weightless simulator. The control computer 43 also controls the servo mechanism of the main body support drive section 202 of the weightless simulator that supports the base of the space robot and the control section of the tension mechanism that performs constant tension control.

This system operation is explained below. First, the high-performance computer is used to create a model of the space robot, perform motion analysis, create data that allows the robot to actually operate, and create motion data for the suspension arm based on these data. , 3,) Performs processing equivalent to the simulation data creation section described in offline data creation method.

This high-performance computer 41 will generate all operational data regarding the space robot and the zero-gravity simulator.

These operating data are transmitted to each control computer 42,43 using R3-232C. Each control computer 42.
43 converts the received data into instruction values for the servo control boards of each joint of the robot, and sends them to each servo control board to operate the robot. The computers 42 and 43 are synchronized and controlled so that the base section, arm, and suspension arm section operate in an accentuated manner. Also, the control computer 43
independently controls the tension mechanism.

4.2. System configuration ■ System configuration ■ uses multiple control computers.

This system configuration (2) is shown in FIG. In the figure, 44
．． 45 and 46 are all control computers, and in this configuration, the three control computers 44 to 46 share control of the robot and creation of operation data for each part, distributing the load associated with data creation. I'm trying. Here, the left arm control computer 44 controls the left arm servo mechanism and the left hanging arm servo mechanism, and the right arm control computer 46 controls the right arm servo mechanism and the right hanging arm servo mechanism. The main body control computer is designed to control the main body servo mechanism and tension control section.

Main body control needle W machine 45 and arm control computer 44.
Between 46 and 46, data can be exchanged using R3-232C, and synchronous communication can be performed using parallel input/output channels.

The operation of this system (2) will be explained below.

First, a computer that controls the control system for the space robot's base creates a model of the space robot, performs motion analysis, and determines the movement of the base. Unless the operation of the base section is determined, the operation related to the hanging arm cannot be determined, so the arm control computers 44 and 46 wait for the base control computer 45 to determine the operation of the base section.

Once the operation of the base is determined, the data is transferred to R3-2
32C to the arm control computers 44 and 46. The arm control computer generates motion data regarding the arm and the hanging arm based on the received base motion data.

When arm-related operation data generation in the arm control computers 44 and 46 is completed, each control computer 44 to 4
6 operates the space robot and the weightless simulator while synchronizing each other via parallel input/output channels.

At this time, each of the computers 44 to 46 performs a process of converting each operation data into an instruction value to the servo mechanism section.

The zero-gravity simulation experiment system described above was intended to simulate the behavior of a multi-jointed structure in zero-gravity space on the ground, but it is of course not limited to this, and the tension value of the constant-tension suspension mechanism can be adjusted appropriately. If chosen, it can also simulate the behavior of articulated structures in low-gravity environments, such as the lunar surface.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a constant tension hanging mechanism with a simple configuration using a winding method.

By using this constant tension suspension mechanism, it is possible to realize a zero-gravity simulation experiment device that creates an environment close to a three-dimensional zero-gravity space in a laboratory on the ground. This makes it possible to repeatedly conduct simulation experiments of the target's operation in zero-gravity space over a long period of time, allowing for careful preliminary evaluation of the performance of the sensor system, actuator system, control system, etc. in zero-gravity space that makes up the target. This makes it possible to construct more reliable hardware such as space robots.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the principle of the present invention; Figure 2 is a diagram explaining the processing outline of the off-line zero-gravity simulation system; Figure 3 is a diagram explaining the hardware concept of the system; The figure is a perspective view of the specific hardware configuration of the system in Figure 2, Figure 5 is a top view of the device in Figure 4, Figure 6 is a side view of the device in Figure 4, and Figure 7 is the joint configuration of the arm. Figure 8 is an explanatory diagram of various suspension tension adjustment methods, Figure 9 is an explanatory diagram illustrating how to deal with the vertical vibration component of the link, Figure 10 is a diagram showing the schematic configuration of the arm, and Figure 11 is an explanatory diagram of various suspension tension adjustment methods. The figure shows the configuration of the gimbal, Figure 12 illustrates the configuration of the counter balancer, Figure 13 is a front view of the winding mechanism, Figure 14 is a side view of the winding mechanism, and Figure 15 is a diagram explaining the configuration of the counter balancer. A top view of the winding mechanism, FIG. 16 is a diagram explaining various tension detection methods, FIG. 17 is a diagram explaining the principle of the tension detection mechanism, FIG. 18 is a diagram explaining the joint configuration of the hanging arm, Figure 19 is a diagram explaining the degree of freedom configuration of the main body support drive part, Figure 20 is a diagram explaining the degree of freedom of the entire mechanical part, Figure 21 is a diagram explaining input and output to the motion analysis software, The figure is a diagram explaining the processing concept of the control system that maintains the hanging direction vertically in a feedforward manner, Figure 23 is a diagram explaining the processing concept of the offline zero-gravity simulation system ■, and Figure 24 is the optical angle detection sensor. Figures 25 and 26 are diagrams explaining the component force detection sensor, Figure 27 is a diagram explaining the processing concept of the online zero-gravity simulation system I, Figure 28 is the multi-jointed structure Figure 29 is a diagram explaining the algorithm for moving the multi-joint structure base; Figure 30 is the processing of the online zero-gravity simulation system ■. Figure 31 is a perspective view showing the specific hardware configuration of system H in Figure 30. Figure 32 is a diagram explaining the principle of the suspension method suspended above the vertical line of the center of gravity. Figure 33 is a static Figure 34 explains the method for determining the hanging position and tension value based on the principle of mechanical balance. Figure 34 explains the eclectic suspension method using a counter balancer. Figure 35 explains the algorithm for maintaining the hanging direction vertically. Figure 36 is a system outline diagram explaining the winding motor torque control method ■. Figure 37 is a system outline diagram explaining the winding motor torque control method ■. Figure 38 is a system outline diagram explaining the winding motor torque control method ■. Figure 39 is a system outline diagram explaining the control method ■; Figure 39 is a system outline diagram explaining the speed control method of the winding motor; Figure 40 is a block diagram showing the configuration of the control circuit for controlling the winding motor; Figure 41. is the computer system configuration I of the zero-gravity simulation experiment device.
Figure 42 shows the computer system configuration of the zero-gravity simulation equipment.
FIG. In the figure, ■...Simulation data creation unit, 2...Zero gravity simulator, 3...Multi-joint structure, 11...-Multi-joint structure numerical model, 12...Motion analysis software, 13.
...Simulation display software, 14.--Data conversion software for zero gravity simulator, 21.. Zero gravity simulation control section, 22.. Zero gravity simulation mechanism section, 31.. Multi-joint structure control section, 32..・Multi-joint structure mechanism part, 41...
・High-performance computer, 42-46...control computer, 20
DESCRIPTION OF SYMBOLS 1--Constant tension suspension mechanism section, 202--Main body support drive section, 203--Frame, 204--2 degrees of freedom robot mechanism, 205--Wire winding mechanism, 206--
-Tension sensor, 207... gimbal, 208...
6 degrees of freedom robot mechanism, 210...wire, 230-
...DC motor with reducer, 231...-shaft coupling, 23
2...Ball spline, 233...-Ball spline nut, 234...Ball spline shaft, 235
-- Winding drum, 236 -- Bearing mounting plate, 237 -- Guide roller with protrusion, 238 -- Guide roller support shaft, 239 -- Bearing for guide roller, 240 -- Motor mounting plate, 241 --・・Support bearing, 250.251・−
・Wire guide roller, 252...Uneven roller, 25
3...Plate spring, 254-...Strain gauge, 301.30
5... Multi-joint structure base part, 3o2... Multi-joint mechanism part, 303... Arm, 304... Hand, 3
05... Pace, 330... Optical angle detection sensor, 331... Light emitter, 340... Component force detection sensor,
332... Photoreceptor, 341-6 degrees of freedom sensor, 34
2...Ball bearing part, 343...Cover 351...
6-degree-of-freedom sensor, 260-...control circuit, 261-2
64... Control software, 270... Comparison section, 271.
...observer, 272...-feedback adjustment section,
273.274...integrator

Claims (1)

[Claims] 1. A wire (102) for suspending a target object (101), a tension sensor (103) for measuring the tension applied to the wire (101), and winding/unwinding the wire (101). a winding mechanism section (104) for winding the wire (104), and a winding mechanism section (104) for
a control unit (105) that controls the winding/unwinding of the winding mechanism unit (104) so that the tension applied to the winding mechanism (104) is constant;
), and set the hanging position of the wire (101) to the wire (101).
) is vertically moved with a degree of freedom in the horizontal direction. 2. The target object (101) is a multi-joint structure having a multi-joint arm with 6 degrees of freedom, and this arm is suspended by a plurality of wires, and the tension sensor (103)
, the winding mechanism section (104), and the control section (10
5) and the suspension position movement mechanism section (106) are provided corresponding to these plurality of wires, respectively, and the suspension position movement mechanism section (106) articulates the bending axis and the linear axis adjacent thereto. The tensile tensioner according to claim 1, which is a horizontal multi-jointed suspension arm in which a plurality of stages are connected as one unit, and a bending shaft and/or a winding mechanism section (104) of the next stage is mounted on a table of a linear shaft. Constant hanging mechanism. 3. Consists of joints with 6 degrees of freedom in total: 3-axis orthogonal coordinate joints that take 3-dimensional positions, 3-axis rotation and 3-axis bending that take postures in 3 directions, and a tabletop that takes 2-axis positional degrees of freedom in the horizontal plane. The degree of freedom of the vertical axis rotation is connected to this, and the vertical axis translational position degree of freedom is connected in series to this, and the remaining two axes of bending and rotational position degrees of freedom are arranged so that they are orthogonal to each other and adjacent. A multi-joint structure base is connected to the rotary joint of the suspension arm, and a support drive unit is provided between the degree of freedom of posture of vertical rotation and the degree of freedom of vertical movement position, and the bending axis of the first stage of the hanging arm is connected. 2. The constant tension suspension mechanism described in 2. 4. A gimbal is further provided, which is connected to the arm side of the wire (102) and prevents interference between the six-degree-of-freedom movement of the arm and the wire suspending the arm, and the multi-jointed arm is capable of bending and/or torsion. The joints on both sides of this multi-jointed arm are used as wire hanging positions, and the center of the gimbal is placed at the intersection of the bending axis of the bending joint and the rotation axis of the adjacent rotary joint. 4. The tension constant according to claim 2 or 3, wherein counterbalances are provided in the rotational part and the bending part of the arm to fix the center of gravity of the joint part at the center of the gimbal with respect to rotational movement in the rotational joint and bending movement in the bending joint. Hanging mechanism. 5. An angle sensor (for detecting the inclination of the wire (102))
107), and is configured to feed back the wire inclination angle detected by the angle sensor to the hanging position moving mechanism section (106) to control the wire hanging position so that the wire (102) is oriented in the vertical direction. A constant tension suspension mechanism according to any one of claims 1 to 4. 6. The constant tension applied to the wire (102) is applied to the target object (
6. The constant tension suspension mechanism according to claim 1, wherein the constant tension suspension mechanism is set to a size that cancels the gravity of the object (101), thereby simulating the behavior of the target object (101) in a zero gravity environment. 7. A winding drum having a spiral groove with a diameter larger than the diameter of the wire for suspending the object on its outer circumferential surface, a spline that provides freedom of movement in the direction of the rotational axis of the winding drum, and a groove in the winding drum. A guide roller that has a protrusion that engages with the winding drum and rotates as the winding drum rotates to guide the winding drum in the direction of its rotation axis; and a motor that rotationally drives the winding drum. Wire winding mechanism. 8. Two rollers arranged on the base body to guide the wire vertically downward to suspend the object, and two rollers vertically below the rollers so as to receive the horizontal component of the tension by the wire guided by the rollers. A roller with different heights arranged between the rollers, a leaf spring that supports the roller on the base at the different height and is distorted according to the horizontal component of the tension, and a leaf spring that is attached to the leaf spring and detects the amount of distortion of the leaf spring. A tension sensor used in a suspension mechanism comprising a strain gauge. 9. A first axis and a second axis adjacent to each other outward from the center;
A gimbal used in a suspension mechanism having a three-axis rotation mechanism, in which the second axis and the third axis are orthogonal to each other, and the third axis is a vertical axis and is configured to rotate by twisting the wire itself.