KR20210069246A - Method for weight and position of 6-dof motion platform - Google Patents

Abstract

The present invention relates to a method for estimating the load weight and position of a 6-DOF motion platform that enables the subsequent process of the motion simulator to be executed by estimating the position and weight of the center of gravity of the motion platform that mechanically operates the motion simulator. The method comprises: a first step in which in a motion platform in which the mounting pad on which the boarding box is seated is supported by six linear actuators and operated, there is no driving load other than the basic load of the mounting pad, and the weight of the basic load is located at the origin in the basic posture of the mounting pad, the servomotor torque sensor senses and collects the basic torque of the servomotor for each linear actuator; a second step in which the servomotor controller controls the servomotor to set the mounting pad to the basic posture in a state where the weight of the driving load is present on the mounting pad, and the servomotor torque sensor senses and collects the driving torque for each linear actuator; a third step in which the load recognition module applies the driving torque to a Jacobian algorithm, calculates the sum of the Z-direction loads applied to the mounting pad, and checks the driving load weight; and a fourth step in which the position recognition module calculates and confirms the driving load position by applying the driving torque to the Jacobian algorithm.

Description

Method of estimating load weight and position of 6-DOF motion platform {METHOD FOR WEIGHT AND POSITION OF 6-DOF MOTION PLATFORM}

The present invention relates to a method for estimating the load weight and position of a 6-DOF motion platform that enables the subsequent process of the motion simulator to be executed by estimating the position and weight of the center of gravity of the motion platform that mechanically operates the motion simulator.

In general, a motion simulator is a device that allows a user to feel the movement of virtual reality as if it were real by reproducing dynamic changes to fit a virtual environment controlled by a computer. It is widely used as a simulator for games or theaters so that you can experience 3D.

Conventional motion simulators are constructed with a 4G system that increases the sense of reality by inducing physical movement of the user, and a motion platform composed of six linear actuators supports the boarding box where the user normally rides.

However, the center of gravity received by the motion platform was inevitably changed depending on the weight and placement position of the user on board, and this inevitably affected the motion of the actuator and affected the movement of the board. Of course, the change in actuator operation became a factor that made the 4G experience different depending on the user, and this caused a difference in the sense of presence that the user objectively received, so it was an urgent task to be improved in the field of motion simulator technology.

In order to solve this problem, a lower body motion detection board has been proposed for detecting the movement and twisting of the center of gravity of a user riding on a simulation board.

However, since the conventional lower body motion detection board requires separate sensor equipment to measure the distance between the connecting axes and detect the degree of torsion between the motion plates, it is inevitable to configure additional equipment to detect the center of gravity of the simulation board, and additional equipment and There was a disadvantage that the development of an algorithm for interworking of

Prior Art Document 1. Patent Registration No. 10-1941465 (Announcement on April 12, 2019)

Accordingly, the present invention is to solve the above problem, the load weight and position estimation method of a 6-DOF motion platform that measures the upper load and the center of gravity position of the motion platform without a separate sensor to determine and notify the suitability of the load position of the problem to be solved.

In order to achieve the above object, the present invention

In a motion platform in which the mounting pad on which the boarding box is seated is supported and operated by six linear actuators, there is no driving load other than the basic load of the mounting pad, and the weight of the basic load is located at the origin in the basic posture of the mounting pad , a first step of the servomotor torque sensor sensing and collecting the basic torque of the servomotor for each linear actuator;

A second step in which the servomotor controller controls the servomotor to set the mounting pad to the basic posture in a state where the driving load weight is present on the mounting pad, and the servomotor torque sensor senses and collects the driving torque for each linear actuator ;

a third step in which the load recognition module applies the driving torque to a Jacobian algorithm, calculates the sum of the Z-direction loads applied to the mounting pad, and checks the driving load weight; and

a fourth step in which the position recognition module calculates and confirms the driving load position by applying the driving torque to the Jacobian algorithm;

It is a method of estimating the load weight and position of a 6-DOF motion platform including

According to the present invention, the suitability of the load position is determined by measuring the position of the upper load and the center of gravity of the motion platform without a separate sensor through the weight estimation algorithm, and when the position of the upper load and the center of gravity is outside the allowable range, an alarm, etc. Since it notifies users such as passengers or managers through the system, stable operation of the motion platform is possible without additional equipment, and there is an effect of realizing the realistic virtual experience function of the motion simulator.

1 is an image showing an embodiment of a motion platform to which a load weight and position estimation method according to the present invention is applied;
2 is a block diagram showing an embodiment of a load sensing system for executing the process of the load weight and position estimation method according to the present invention;
3 is a diagram schematically showing each configuration of a motion platform to which the load weight and position estimation method according to the present invention is applied;
4 is a flowchart sequentially showing the process of the load weight and position estimation method according to the present invention;
5 is an equation showing the appearance of the Jacobian matrix applied to the load weight and position estimation method according to the present invention,
6 is an image showing the basic coordinate structure of the motion platform for constructing the Jacobian matrix of the present invention, and FIG. 7 is a dynamic graph showing the relationship between the basic load applied to the mounting pad of the motion platform and the force of the linear actuator. ,
8 is a dynamic graph showing the relationship between the driving load applied to the mounting pad of the motion platform with a bias in the X direction and the force of the linear actuator;
9 is a dynamics graph showing the relationship between the driving load applied to the mounting pad of the motion platform with a bias in the Y direction and the force of the linear actuator.

The features and effects of the present invention described above will become apparent through the following detailed description in relation to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains can easily implement the technical idea of the present invention. There will be. Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is an image showing an embodiment of a motion platform to which the load weight and position estimation method according to the present invention is applied, and FIG. 2 is a load sensing system executing the process of the load weight and position estimation method according to the present invention It is a block diagram showing an embodiment, and FIG. 3 is a diagram schematically showing each configuration of a motion platform to which the load weight and position estimation method according to the present invention is applied.

1 to 3, the load sensing system 100 for processing the load weight and position estimation method of the present embodiment is to drive the linear actuators 200, 200', 200" of the motion platform (hereinafter '200') The servomotor 110, the servomotor controller 120 that controls the operation of the servomotor 110 and manages the basic posture data, basic load data, and origin position data of the motion platform, and the servomotor for the motion platform operation The servo motor torque sensor 130 for sensing the torque, which is the power of 110, and the torque for each servo motor 110 are applied to the Jacobian algorithm to determine the basic load and driving load applied to the mounting pad 400 Position to calculate and check the position of the basic load and driving load applied to the mounting pad 400 by applying the load recognition module 140 to calculate and check the torque for each servo motor 110 and the Jacobian algorithm and a recognition module 150 .

In addition, the load sensing system 100 of this embodiment executes a warning service when the position of the driving load exceeds the reference range, and an alarm module 160 for the servo motor controller 120 to stop the operation of the servo motor 110 . ) is further included.

The motion platform of the Stewart type is supported by a base frame 300, six linear actuators 200 rotatably installed on the base frame 300, and the linear actuator 200 and boarded on the upper part (C) ) is composed of a mounting pad 400 on which it is mounted. Accordingly, the mounting pad 400 moves up, down, left and right according to the operation of the six linear actuators 200 , and the boarding (C) also moves up, down, left and right according to the movement of the mounting pad 400 . The length and mounting position and mounting angle of the linear actuator 200 are determined according to the specifications of the motion platform.

The linear actuator 200 is a known cylinder-type device that tensions or compresses according to the rotation direction and number of rotations of the servomotor 110 . For reference, since the rack 220 is drawn in and out from the main body 210 according to the rotation direction of the servo motor 110 mounted on the main body 210 of the linear actuator 200, the torque of the servo motor 110 is linear. It is a load received by the actuator 200 .

On the other hand, the boarding box (C) is a space equipped with an operation board that generates and transmits a control signal set to move the boarding box (C) according to the manipulation, and a screen that outputs a simulated image displayed according to the control signal. However, the weight of the user (hereinafter, 'occupant') riding in the boarding box C becomes a load applied to the motion platform, and the load has a physical effect on the linear actuator of the motion platform. However, the unbalanced load puts a strain on the operation of a specific linear actuator and induces a movement different from the set value, which is a behavior different from the simulated image displayed on the screen.

Of course, this behavior is a factor that weakens the reality of the 4G simulation felt by the passengers, so the problem was solved through the following method.

4 is a flowchart sequentially illustrating the process of the load weight and position estimation method according to the present invention, and FIG. 5 is an equation showing the appearance of the Jacobian matrix applied to the load weight and position estimation method according to the present invention, 6 is an image showing the basic coordinate structure of the motion platform for building the Jacobian matrix of the present invention, and FIG. 7 is a dynamic graph showing the relationship between the basic load applied to the mounting pad of the motion platform and the force of the linear actuator, and FIG. 8 is a dynamic graph showing the relationship between a driving load applied with a bias in the X direction to the mounting pad of the motion platform and the force of a linear actuator, and FIG. 9 is a driving applied with a bias in the Y direction to the mounting pad of the motion platform. It is a dynamic graph showing the relationship between the load and the force of the linear actuator.

Reference is made to FIGS. 1 to 9 .

S11; Basic torque and basic load collection stage

When there is no driving load other than the basic load of the mounting pad 400 , and the weight of the basic load is located at the origin in the basic posture of the mounting pad 400 , the servomotor torque sensor 130 is a servomotor for each linear actuator 200 . The basic torque of (110) is sensed and collected.

Here, the basic load is a weight consisting of only the mounting pad 400 and the boarding box (C) without additional load such as the occupant, and the basic posture is the basic load state in which each of the linear actuators 200 is seated. It is a posture to uniformly load and support the mounting pad 400 . In addition, the origin is the center of gravity of the basic load and basic posture.

Therefore, it is determined whether the linear actuator 200 is stabilized based on the basic load, the basic posture, and the origin position.

For reference, a dynamic model that constitutes the motion platform as a formula is called a dynamic model, and the mounting position and mounting angle of the linear actuator 200 are expressed by the Jacobian algorithm of FIG. 5 among the dynamics models of the actuator. Here, the force by the driving torque is applied to the top plate by the Jacobian algorithm, and it supports or moves the driving load.

The basic torque of the linear actuator 200 at the basic load of the basic posture and origin state constitutes the relational expression of [Equation 1], and the dynamic relation is as shown in FIG. 7 .

The direction vector of the six actuators 200 is determined by the geometry (refer to FIG. 6) between the mounting pad 400, the base frame 300, and the actuator 200 constituting the six-way induction motion platform. do. As a result, the vector coordinates of each of the six points of the mounting pad 400 and the base frame 300 to which both ends of the actuator 200 are connected are confirmed by the 'Skew Symmetric Matrix' and 'Rotational Matrix' algorithms.

S12; Linear actuator driving torque collection stage

In a state where the driving load weight exists on the mounting pad 400, the servo motor controller 120 controls the servo motor 110 to set the mounting pad 400 to the basic posture, and the servo motor 110 torque sensor The driving torque for each linear actuator 200 is sensed and collected.

More specifically, when a driving load is added to the basic load due to the passenger's boarding, it is determined whether the driving load is within a reference range based on the origin to realize a stable operation of the motion platform and an optimized simulation environment. To this end, in a state in which the mounting pad 400 maintains the basic posture, the force borne by the linear actuator 200 is checked. Here, the force is a driving torque of the servo motor 110 , and the driving torque is sensed by the servo motor torque sensor 130 .

S13; Checking the driving load weight

The load recognition module 140 applies the driving torque to the Jacobian algorithm of FIG. 5 , calculates the sum of the Z-direction loads applied to the mounting pad 400 , and checks the driving load weight.

To describe this step in more detail, the load recognition module 140 receives the driving torque for each linear actuator 200 sensed by the servomotor torque sensor 130 through the servomotor controller 120 . Regardless of the origin of the driving load, the total load in the Z direction is calculated based on [Equation 1], and the weight of the driving load is checked through this.

S14; Checking the position of the driving load

The position recognition module 150 calculates and confirms the driving load position by applying the driving torque to the Jacobian algorithm.

만큼 편중한다.When the driving load is biased in the X direction as shown in FIG. 8, the location of the bias in the X direction of the driving load can be calculated through [Equation 2] according to the Jacobian algorithm. In this embodiment, the X-direction biased position is based on the origin.

as biased as

만큼 편중한다.Also, as shown in FIG. 9, the Y-direction biased position of the driving load can be calculated through [Equation 3]. In this embodiment, the Y-direction biased position is based on the origin.

as biased as

In the end, the position recognition module 50 calculates the biased position of the driving load in the x,v two-dimensional mounting pad 400 based on the origin, and the driving load position information for determining whether the operation stability of the boarding box (c) is to collect

S15; Step to check that the standard range is exceeded

The alarm module 160 executes a warning service when the position of the driving load exceeds a reference range, and controls the servomotor controller 120 to stop the operation of the servomotor 110 .

The warning service may be a warning broadcast, a forced stop of the motion platform, a change of location of the passenger, and the like.

The reference range may be graded according to the distance from the origin, and the subsequent warning service may be differentiated according to the graded risk level.

In the detailed description of the present invention described above, although it has been described with reference to preferred embodiments of the present invention, those skilled in the art or those having ordinary knowledge in the art will have the spirit of the present invention described in the claims to be described later. And it will be understood that various modifications and variations of the present invention can be made without departing from the technical scope.

100; load sensing system 110; servo motor
120; servo motor controller 130; Servo motor torque sensor
140; load recognition module 150; location recognition module 160; alarm module
200, 200', 200"; linear actuator 210; body
220; rack 300; base frame 400; mounting pad
c; boarding

Claims (2)

In a motion platform in which the mounting pad on which the boarding box is seated is supported and operated by six linear actuators, there is no driving load other than the basic load of the mounting pad, and the weight of the basic load is located at the origin in the basic posture of the mounting pad , a first step of the servomotor torque sensor sensing and collecting the basic torque of the servomotor for each linear actuator;
A second step in which the servomotor controller controls the servomotor to set the mounting pad to the basic posture in a state where the driving load weight is present on the mounting pad, and the servomotor torque sensor senses and collects the driving torque for each linear actuator ;
a third step in which the load recognition module applies the driving torque to a Jacobian algorithm, calculates the sum of the Z-direction loads applied to the mounting pad, and checks the driving load weight; and
a fourth step in which the position recognition module calculates and confirms the driving load position by applying the driving torque to the Jacobian algorithm;
Load weight and position estimation method of a 6-DOF motion platform comprising a. The method of claim 1,
After the fourth step, if the alarm module confirms that the reference range of the driving load position is exceeded, a warning service is executed, and the servo motor controller stops the servo motor. Method of estimating load weight and position of the motion platform.

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