KR101270629B1 - Driving method for planetary exploration rover having multi joint and leg - Google Patents

Abstract

PURPOSE: A driving method of a multi-joint rover for exploring a planet is provided to minimize consumption of the power and to secure driving safety by driving each motor through a motor control input value stored at an operational database. CONSTITUTION: A driving method of a multi-joint rover(100) for exploring a planet comprises the following steps: a step of setting target rotation angle of each position control motor; a step of maintaining level of an upper platform(110); a step of setting moving angle of the rover by recognizing steering angle of a current rover and controlling a steering motor according to predetermined moving angle; and a step of setting speed of a wheel by a position control unit and controlling a driving motor(158) according to the predetermined speed.

Description

DRIVING METHOD FOR PLANETARY EXPLORATION ROVER HAVING MULTI JOINT AND LEG}

The present invention relates to a driving method of the articulated rover for planetary exploration, and more particularly, each motor through a motor control input value stored in an operation DB (database) defining geometrical correlations between the attitude control motor, the steering motor, and the driving motor. The present invention relates to a method of driving a planetary exploration articulated rover that minimizes power consumption and secures driving stability by prolonging the mission time of the planetary exploration articulated rover.

Minimizing power consumption and securing driving stability by minimizing motor driving due to obstacles or road surface conditions are essential for the operation of the planetary rover.

Existing planetary rover's traveling device can be classified into track type, wheel type and leg type. The track-type rover has a large contact surface with the ground, so it is easy to secure high stability and is simple in terms of system.However, the large friction area between the track and the ground causes a large loss of energy. There is this.

The driving of the wheeled rover can be equipped with a high speed and many payloads with a simple algorithm. However, in a driving environment such as overcoming obstacles larger than the diameter of the wheel or the separation of the road surface, the driving route has to be modified to reach the destination.

The leg-type rover is easy to maintain the stability of the rover in a situation such as slopes, superelevation slopes, large obstacles and the like, it is suitable to use in an environment lacking information on the terrain.

Conventional planetary articulated rover 100 as described above, as shown in Figures 1 to 4, LRF (Laser Range Finder) 120, TOF (Time of Flight) camera 130, gyro sensor ( The upper platform 110 on which the tilt sensor (not shown) and the acceleration sensor (not shown) are mounted, the lower platform 140 supporting the upper platform 110, and the lower surface of the lower platform 140. A plurality of posture control motors 157 are installed in the plurality of links 151, 152, 153, 154 by the steering motor 156 and the steering motor 158 at the same time to perform the multiple degree of freedom movement It is configured to include a traveling module for driving by rotating the wheel 155.

In the conventional planetary rover articulated rover 100 as described above, the upper platform 110 is kept horizontal by the attitude control motor 157, and the planetary articulated articulated rover 100 is controlled by the steering motor 156. Is steered and moved by the operation of the traveling motor 158.

The planetary rover articulated rover (100) secures system stability and drives unnecessary posture control motor (157) and driving motor (158) by horizontally maintaining the upper platform (100) on which precision components are mounted in various road conditions. By limiting this problem, the necessity of prolonging the mission of planetary exploration through minimizing power consumption is emerging.

The present invention is to solve the above problems, an object of the present invention is to drive each motor through the motor control input value stored in the operation DB (database) that defines the geometric correlation of the attitude control motor, steering motor and driving motor It is to provide a driving method of the planetary exploration articulated rover that minimizes the power consumption and secures the driving stability, thereby prolonging the mission time of the planetary exploration articulated rover.

The object of the present invention is an upper platform equipped with a laser range finder (LRF), a time of flight (TOF) camera, a gyro sensor, a tilt sensor, and an acceleration sensor, a lower platform supporting the upper platform, and the lower platform. It is installed on the lower surface of the platform in a plurality of planetary exploration articulation including a traveling module which is driven by the steering motor and rotates the wheel by the driving motor while simultaneously carrying out multiple degrees of freedom movement by a plurality of attitude control motors. In the rover driving method, (a) the motor control unit recognizes the encoder value of each attitude control motor to recognize the current rotation angle of each attitude control motor, and sets the target rotation angle of each attitude control motor, ( b) The posture control unit receives the set target rotation angle of each posture control motor to control the rotational speed of each posture control motor to eliminate the multiple degree of freedom movement of the traveling module. Maintaining the horizontal level of the upper platform, and (c) the control unit recognizing the steering angle of the current rover obtained from the gyro sensor to set the moving angle of the rover, and controlling the steering motor according to the set moving angle. And (d) the operation controller sets the speed of the wheel to control the traveling motor according to the set speed.

In addition, the motor control unit in step (a) to recognize the encoder value of each attitude control motor to recognize the current rotation angle of each attitude control motor can be calculated by Equation 1 below.

<Formula 1>

Where degree: current rotation angle of each control motor, Y: gear ratio, E: encoder value, P: encoder pulse, 4: multiplier

In addition, the multi-degree of freedom movement speed of the traveling module controlled by the attitude controller of step (b) may be calculated by Equation 2 below.

<Formula 2>

: 주행모듈의 운동속도,

: 목표각도,

: 현재각도,

: 목표시간,

: 현재시간, rps : 자세제어모터의 회전속도here,

: Speed of travel module,

= Target angle,

: Current angle,

: Target time,

: Current time, rps: Rotational speed of attitude control motor

In addition, the moving angle of the rover set by the operation controller of step (c) may be calculated by Equation 3 below.

<Formula 3>

: 로버의 이동각도,

: 로버의 기준각도,

: 로버의 현재각도,

: 자이로 센서각도here,

Is the rover's moving angle,

= Reference angle of the rover,

Rover's current angle,

Gyro Sensor Angle

In addition, the speed of the wheel set by the operation controller of step (d) can be calculated by Equation 4 below.

<Equation 4>

: wheel velocity,

: 상수, E : encorder pluse,

: wheel radius,

: elapse time, R : wheel ratiohere,

: wheel velocity,

: Constant, E: encorder pluse,

wheel radius,

: elapse time, R: wheel ratio

By this, each motor is driven through the motor control inputs stored in the motion DB (database) which defines the geometrical correlation between the attitude control motor, the steering motor and the driving motor, thereby minimizing the power consumption and securing the driving stability. Joint rover has an effect of extending the duration of the mission.

1 is a view showing a planetary rover articulated rover.
2 is a view showing the lower platform and the traveling module of the planetary rover articulated rover.
3 and 4 are views showing the traveling module of the planetary rover articulated rover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

The present invention operates the geometrical correlation of the steering motor 156, the attitude control motor 157 and the driving motor 158 in various road surface conditions such as slope, superelevation, obstacles in the planetary rover articulated rover (100). The motor control input value stored in the DB consists of a driving method that overcomes the obstacle environment while maintaining the horizontality of the upper platform 110 where the precision parts are concentrated and mounted to secure the motor driving to minimize power consumption and to ensure the stability of the system. It is.

The motor control unit has two thread structures to control one link (151, 152, 153, 154). 'Velo Calc Thread' is a thread that calculates the speed of the motor in real time and synchronizes with other axes. Velo & Pos Change Thread is a thread that transfers data calculated in Velo Calc Thread to MTC LIB (USB Device), in order to match the sequence with other motors. The rover 100 has 36 motors (6 driving modules x 6 joints) and the driving motor 158 controls the speed related to the running of the rover 100 so that the excitation control is performed using a total of 30 motors. Should be. Therefore, a total of 30 * 2 (60) threads will loop to control the motor.

The attitude control motor 157 controls the data for controlling each link 151, 152, 153, and 154 to a degree value. The encoder value of each axis should be converted to degree, and the target degree value to be moved should be converted to encoder value. The formula for converting an encoder value to degree and the formula for converting a degree value to an encoder value are shown in Equation 1 below.

<Formula 1>

Where degree: current rotation angle of each control motor, Y: gear ratio, E: encoder value, P: encoder pulse, 4: multiplier

You can set the current rover's posture and target angle by using the degree and encoder values obtained from the above equation.

On the other hand, the posture control unit gives the command of the angle value and time for one driving module 150 at a time for the posture control. The target angle values of the links 151, 152, 153 and 154 are input to calculate a time for moving to the target angle values of the links 151, 152, 153 and 154. Such a posture control method moves one driving module 150 at a time. When the moving angle is large, the speed increases, and when the moving angle is small, the speed decreases. The speed of each driving module 150 is shown in Equation 2 below.

<Formula 2>

: 주행모듈의 운동속도,

: 목표각도,

: 현재각도,

: 목표시간,

: 현재시간, rps : 자세제어모터의 회전속도here,

: Speed of travel module,

= Target angle,

: Current angle,

: Target time,

: Current time, rps: Rotational speed of attitude control motor

Until the movement of the driving module 150 is completed, the speed value is calculated in the thread to synchronize the motors.

In addition, the operation controller controls and drives the posture control motor 157 of the driving module 150 according to each situation based on information corresponding to each operation from a pre-calculated operation DB. When a command is issued, the DB is read and parsed, and the number of DB threads is operated.

The longitudinal drive of the wheel 155 of the rover 100 is implemented through speed control, and the steering of the rover 100 is implemented by controlling the position of the steering motor 156 through the position control. Since Odometry is calculated to know, the steering axis of each wheel 155 always has the same direction.

In calculating the angle by the steering shaft, the angle of recognizing the direction of the rover 100 is two in total. That is, by using the steering angle obtained from the gyro sensor and the encoder mounted on the steering motor 156, the moving angle can be obtained from Equation 3 below.

<Formula 3>

: 로버의 이동각도,

: 로버의 기준각도,

: 로버의 현재각도,

: 자이로 센서각도here,

Is the rover's moving angle,

= Reference angle of the rover,

Rover's current angle,

Gyro Sensor Angle

Thus, the reason for obtaining the moving angle of the rover 100 is to obtain the Odometry, which obtains the relative coordinates by recognizing the moving path of the rover 100 and has three output data of X, Y, and Theta. Odometry calculation of the rover 100 is shown in Equation 4 below.

<Equation 4>

: wheel velocity,

: 상수, E : encorder pluse,

: wheel radius,

: elapse time, R : wheel ratiohere,

: wheel velocity,

: Constant, E: encorder pluse,

wheel radius,

: elapse time, R: wheel ratio

와 같이 선속도 값을 추출할 수가 있다.The speed value of the wheel 155 can be obtained from Equation 4, and when the linear speed value is extracted from the wheel 155 speed value,

The linear velocity value can be extracted as

The travel distance by linear velocity is calculated from Equation 5 below.

<Equation 5>

Here, the values of the current positions X and Y of the rover 100 are calculated from Equation 6 below by using the moved distance and the moving direction.

&Lt; EMI ID =

,

,

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. It will be understood that various changes and modifications may be made without departing from the scope of the present invention.

100: planetary exploration articulated rover 110: upper platform
120: LRF 130: TOF Camera
140: lower platform 150: driving module
151, 152, 153, 154: Link 155: Wheel
156: steering motor 157: attitude control motor
158: driving motor

Claims (5)

An upper platform equipped with a laser range finder (LRF), a time of flight (TOF) camera, a gyro sensor, an inclination sensor, and an acceleration sensor, a lower platform supporting the upper platform, and a plurality of installations on the lower surface of the lower platform In the traveling method of the planetary exploration articulated rover comprising a traveling module which is driven by a steering motor and is driven by a steering motor and rotates a wheel by a traveling motor at the same time as a multi-degree of freedom movement by a plurality of attitude control motors,
(a) a motor control unit recognizing encoder values of each attitude control motor to recognize a current rotation angle of each attitude control motor, and setting a target rotation angle of each attitude control motor;
(b) maintaining the level of the upper platform by controlling the multi-degree of freedom movement of the traveling module by controlling the rotational speed of each of the attitude control motors by receiving the set target rotation angle of each of the attitude control motors;
(c) an operation control unit recognizing a steering angle of the current rover obtained from the gyro sensor, setting a moving angle of the rover, and controlling the steering motor according to the set moving angle;
(d) setting the speed of the wheel by the operation controller to control the driving motor according to the set speed,
In the step (a), the motor controller recognizes the encoder value of each attitude control motor and recognizes the current rotation angle of each attitude control motor according to Equation 1 below. Driving method.
<Formula 1>

Where degree: current rotation angle of each control motor, Y: gear ratio, E: encoder value, P: encoder pulse, 4: multiplier delete The method of claim 1,
The multi-degree of freedom movement speed of the traveling module controlled by the attitude control unit of step (b) is calculated by the following equation (2).
<Formula 2>

here,

: Speed of travel module,

= Target angle,

: Current angle,

: Target time,

: Current time, rps: Rotational speed of attitude control motor The method of claim 1,
The moving angle of the rover set by the operation control unit of the step (c) is calculated by the following equation 3, planetary exploration articulated rover driving method.
<Formula 3>

here,

Is the rover's moving angle,

= Reference angle of the rover,

Rover's current angle,

Gyro Sensor Angle The method of claim 1,
The speed of the wheel set by the operation control unit of the step (d) is calculated by the equation 4 below.
<Equation 4>

here,

: wheel velocity,

: Constant, E: encorder pluse,

wheel radius,

: elapse time, R: wheel ratio

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