KR102479904B1 - Friction compensation system and friction compensation method of multi-degree-of-freedom robots - Google Patents

Abstract

A friction compensation system for a multi-DOF robot according to an embodiment of the present invention includes a motor unit providing a driving force to each axis of the multi-DOF robot; A sensor unit for acquiring state information values in each axis of the multi-degree-of-freedom robot according to a user's direct teaching; an identification unit that detects a characteristic value using the state information value to identify friction and calculates a first parameter; a control unit generating a control command for the motor unit; and an algorithm for calculating a second parameter of the friction model using the first parameter, and calculating a control input value for the control unit using the second parameter. , provides a friction compensation system for multi-degree-of-freedom robots.

Description

Friction compensation system and friction compensation method for multi-degree-of-freedom robots

The present invention relates to a friction compensation system and friction compensation method for a multi-DOF robot, and more particularly, to a friction compensation system and friction compensation method for a multi-DOF robot for setting friction parameters to ensure passivity in direct teaching of a cobot. It's about compensation.

A Collaborative Robot (COBOT) is a robot that works together with humans and is designed primarily to interact with humans at production sites. If industrial robots, which were previously used in production sites, were used in a work space separated from humans as a substitute for humans, collaborative robots can work together with humans as a complement to humans and increase work efficiency.

Collaborative robots are robots that perform close physical interactions with users and must be able to respond easily to external forces. In particular, in order to easily teach the robot what the user wants to implement, precise and efficient teaching must be possible, and a high-performance direct teaching function that can easily respond to external force applied by the user is required.

At this time, the biggest factor that makes direct teaching of the cobot difficult is the frictional force acting on each joint, and it is not easy to perform friction compensation while ensuring the stability of all joints of the multi-degree-of-freedom cobot.

Existing friction compensation methods are largely classified into three types.

The first is a friction compensation method based on a friction model. However, existing methods require additional sensors and identification devices for friction identification and are limited to single degree of freedom systems. Moreover, existing methods do not guarantee passivity, so it is difficult to easily extend them to multi-degree-of-freedom collaborative robots.

The second is a friction compensation method without a friction model. Since most of these methods use observers, they are difficult to use for direct teaching of cobots and are mainly applied for the purpose of improving the robot's position control performance.

The third method uses the observer and the joint torque sensor at the same time. The friction compensation method without a model can be applied to direct teaching, but it has disadvantages in terms of price competitiveness and maintenance because each joint must be equipped with a joint torque sensor.

Republic of Korea Patent Registration No. 10-1100108 (2011.12.22)

The problem to be solved by the present invention is a friction compensation system for a multi-degree-of-freedom robot that calculates and sets parameters of a friction model based on the theory of passivity to ensure user safety in a situation where a cobot is taught directly, and It is to provide a friction compensation method.

The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the following description.

A friction compensation system for a multi-DOF robot according to an embodiment of the present invention for solving the above problems includes a motor unit providing a driving force to each axis of the multi-DOF robot; A sensor unit for acquiring state information values in each axis of the multi-degree-of-freedom robot according to a user's direct teaching; an identification unit that detects a characteristic value using the state information value to identify friction and calculates a first parameter; a control unit generating a control command for the motor unit; and a calculation unit having a built-in algorithm for calculating a second parameter of the friction model using the first parameter and calculating a control input value for the control unit using the second parameter.

In one embodiment, the calculator may have a built-in algorithm for calculating a second parameter such that energy input to the friction compensation system is greater than or equal to energy output from the friction compensation system.

In one embodiment, the sensor unit may obtain dynamic and kinematic state information values of each axis of the multi-DOF robot according to a user's direct teaching.

In one embodiment, the sensor unit may acquire one or more of position, speed, temperature, and weight in each axis of the multi-DOF robot as a state information value.

In one embodiment, the identification unit may calculate and obtain one or more of information values for stiffness, viscosity, frictional force, and stribeck speed as a first parameter from the state information value.

In one embodiment, the calculation unit may have a built-in algorithm to which a LuGre friction model is applied.

In one embodiment, the LuGre friction model may include, as a parameter, a function having a velocity of a joint axis of a multi-DOF robot obtained from the sensor unit as a variable.

In one embodiment, the sensor unit obtains a velocity or acceleration value in each axis of the multi-degree-of-freedom robot according to a user's direct teaching, and the calculation unit uses the velocity value or acceleration value obtained from the sensor unit as a parameter. An algorithm for limiting the speed in each axis of the multi-DOF robot within a predetermined range may be further built-in.

A friction compensation method for a multi-DOF robot according to an embodiment of the present invention for solving the above problems includes a detection step of acquiring state information values in each axis of the multi-DOF robot; an identification step of identifying occurrence of friction using the state information value; A calculation step of calculating a control input value by calculating parameters of the friction model; and a control step of controlling motor driving of each axis of the multi-degree-of-freedom robot.

In one embodiment, the algorithm in the calculation step calculates the parameters of the friction model so that the energy input to the robot system in which friction compensation is performed is greater than or equal to the energy output from the robot system in which friction compensation is performed. can

In one embodiment, the detecting step may be to obtain dynamic and kinematic state information values of each axis of the multi-DOF robot according to a user's direct teaching.

In one embodiment, the detecting step may be to acquire one or more of position, speed, temperature, and weight in each axis of the multi-DOF robot as a state information value.

In one embodiment, the identifying step may be to calculate and obtain any one or more of information values for stiffness, viscosity, frictional force, and Stribeck speed as a parameter from the state information value.

In one embodiment, the algorithm in the calculation step may be one to which a LuGre friction model is applied.

In one embodiment, the LuGre friction model may include, as a parameter, a function having a velocity of a joint axis of a multi-DOF robot obtained from the sensor unit as a variable.

In one embodiment, the detecting step obtains a velocity or acceleration value in each axis of the multi-DOF robot according to a user's direct teaching, and the calculating step is based on the velocity value or acceleration value obtained from the sensor unit. As a result, an algorithm for limiting the speed in each axis of the multi-DOF robot within a predetermined range may be further performed.

Other specific details of the invention are included in the detailed description and drawings.

According to embodiments of the present invention, at least the following effects are provided.

The friction compensation system and method of the present invention can compensate for the joint friction force of the robot while ensuring the safety of the user by setting friction parameters to ensure passivity in direct teaching of the cobot.

In addition, it can be applied to the mass production stage of cooperative robots including this to provide a consistent and improved direct teaching function.

Effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a schematic diagram conceptually showing energy input and output of a friction compensation system of a multi-degree-of-freedom robot according to an embodiment of the present invention.
FIG. 2 is a block diagram showing the friction compensation system of FIG. 1 in more detail.
FIG. 3 is a block diagram conceptually showing friction compensation by the friction compensation system of FIG. 2 .
4 is a flowchart sequentially showing each step of a method for performing friction compensation of a multi-degree-of-freedom robot according to an embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

In addition, the embodiments described in this specification will be described with reference to cross-sectional views and/or schematic views, which are ideal exemplary views of the present invention. Accordingly, the shape of the illustrative drawings may be modified due to manufacturing techniques and/or tolerances. In addition, in each drawing shown in the present invention, each component may be shown somewhat enlarged or reduced in consideration of convenience of description. Like reference numbers designate like elements throughout the specification.

Hereinafter, a specific embodiment of a friction compensation system for a multi-degree-of-freedom robot according to the present invention will be described with reference to the drawings.

1 is a schematic diagram conceptually showing the energy input and output of the friction compensation system 10 of the multi-degree-of-freedom robot (A) according to an embodiment of the present invention, and FIG. 2 shows the friction compensation system 10 of FIG. 1 in more detail. 3 shows a block diagram conceptually showing friction compensation by the friction compensation system 10 of FIG. 2 .

The friction compensation system 10 of the multi-degree-of-freedom robot (A) according to the present invention sets the friction model parameters based on the theory of passivity to ensure the safety of the user in the situation of directly teaching the cobot. as its main technical feature.

The passivity theory is a theory that observes the energy of the system and guarantees the passivity of the system if the output energy is always smaller than the input energy. As shown in FIG. 1, the friction compensation system 10 according to an embodiment of the present invention It is characterized in that the energy input to the system (E _input ) is implemented to be greater than or equal to the energy output from the system (E _output ). That is, based on the robot system system, the user's stability can be guaranteed by maintaining the output energy (E _output ) to be equal to or less than the input energy (E _input ) at all times.

Since the passivity theory is obvious to those skilled in the art, a detailed description thereof will be omitted.

As shown in FIGS. 2 and 3, the friction compensation system 10 of the multi-DOF robot (A) according to an embodiment of the present invention has a motor providing driving force to each axis of the multi-DOF robot (A). section 100; A sensor unit 200 that acquires state information values in each axis of the multi-degree-of-freedom robot according to a user's direct teaching; an identification unit 400 that identifies friction using the state information value and calculates a first parameter; a controller 300 generating a control command for the motor unit; and an algorithm for calculating a second parameter of the friction model using the first parameter, and calculating a control input value for the control unit 300 using the second parameter. It can be included as a component that forms the basic structure of the system.

The motor unit 100 according to the present invention includes a motor device that provides a driving force to the joint axis of the multi-degree-of-freedom robot (A). More specifically, the motor device may be installed to receive power from a separate power supply source (not shown) and provide a driving force to each joint axis of the multi-degree-of-freedom robot (A).

The sensor unit 200 according to the present invention includes a sensor device installed to measure state information generated on each joint axis of the multi-degree-of-freedom robot (A).

At this time, the state information value obtained by the sensor unit 200 according to an embodiment of the present invention may be a dynamic and/or kinematic state information value of each axis of the multi-DOF robot according to direct teaching by a user. In more detail, the sensor unit 200 may acquire one or more of position, speed, temperature, and weight in each axis of the multi-DOF robot as a state information value.

The identification unit 400 according to the present invention, using the kinematic and / or dynamic state information value obtained by the sensor unit 200, the characteristic value in each axis of the multi-degree-of-freedom robot (A) in the first It is a configuration obtained as a parameter. That is, the identification unit 400 identifies the generation of friction based on the characteristic values in each axis of the multi-degree-of-freedom robot A, and the obtained characteristic value becomes a first parameter and becomes a second parameter to be described later. It can be applied to the friction model of the calculation unit 500 for calculating .

The first parameter calculated by the identification unit 400 according to an embodiment of the present invention, that is, the characteristic value, is the stiffness, viscosity, frictional force, and Stribeck speed of the multi-degree-of-freedom robot (A) on each axis contact surface. It may be any one or more of the information values for

The control unit 300 according to the present invention receives the control input value calculated by the operation unit 500 to be described later, and generates and transmits a driving control command for the motor device. Specifically, it is possible to control energy output from the system of the present invention by generating control commands for power supply, rotational force, and the like for the motor device.

In the calculation unit 500 according to the present invention, a friction model having a characteristic value for the joint axis of the multi-DOF robot (A) transmitted to the identification unit 400 as a parameter is built, and a friction model variable that satisfies the passivity theory is generated. The calculation algorithm is built in. That is, the calculation unit 500 calculates the second parameter of the friction model using the characteristic value calculated from the identification unit 400 as a first parameter, and uses the second parameter to calculate the control unit ( 300) to calculate the control input value.

The control input value calculated by the algorithm built in the calculation unit 500 is transmitted to the control unit 300 of the present invention to control the driving of the joints of the multi-degree-of-freedom robot (A).

At this time, the algorithm of the calculation unit 500 according to an embodiment of the present invention calculates the second parameter using a preset friction model, energy equal to or smaller than the input energy based on the robot system system of the present invention. It is characterized in that a control input value for outputting is calculated. Then, since the control unit 300 generates a control command for the motor unit 100 according to the calculated control input value, the passivity of the robot system system is guaranteed regardless of the energy of the motor unit built in the motor unit 100. You can do it.

Hereinafter, an algorithm based on a friction model built into the calculation unit 500 according to an embodiment of the present invention will be described in detail.

The dynamics of each joint of a typical multi-DOF robot (A) is given as Equation 1 below.

[Equation 1]

는 각각 다자유도 로봇(A)의 관절에 대한 회전위치, 회전속도, 회전각속도를 나타낸다. 또한,

은 로봇의 관성력을,

는 코리올리 힘을,

은 중력을,

는 각각 제어입력으로 사용되는 토크 값 및 다자유도 로봇(A)의 관절에 작용하는 마찰력을 나타낸다.

는 사용자가 다자유도 로봇(A)의 관절 축에 가하는 외력 토크 값을 나타낸다. here,

Represents the rotational position, rotational speed, and rotational angular velocity of the joint of the multi-DOF robot (A), respectively. Also,

is the inertial force of the robot,

is the Coriolis force,

is gravity,

Represents a torque value used as a control input and a frictional force acting on the joints of the multi-DOF robot (A).

represents an external force torque value applied to the joint axis of the multi-degree-of-freedom robot (A) by the user.

)함으로써 아래의 식 2와 같이 구현된다.Direct teaching for a typical multi-degree-of-freedom robot (A) completely compensates for gravity as a control input (

), it is implemented as in Equation 2 below.

[Equation 2]

에 의해서 중렵에 대한 보상이 이루어진 상태에서 자유롭게 움직일 수 있다. 하지만, 여전히 마찰력(

)에 의해 협동로봇의 직접교시 성능이 상당히 저하된다. Accordingly, the multi-degree-of-freedom robot (A) is the user's external force torque value

It is possible to move freely in a state in which compensation for jungryeop is made by However, friction (

), the direct teaching performance of the cobot significantly deteriorates.

In order to solve this problem, the friction compensation system 10 of the multi-degree-of-freedom robot (A) according to the present invention, by the algorithm built in the calculation unit 500, controls input to perform gravity compensation and friction compensation together as follows It can be improved to improve direct teaching performance by modifying the calculation.

The control input torque value calculated by the friction compensation system 10 of the present invention is as shown in Equation 3 below.

[Equation 3]

는 본 발명의 일 실시예에 의한 연산부(500)에서의 마찰모델에 의해 추정되는 마찰력 값을 나타낸다. 즉, 마찰보상을 위해 산출되어야 하는 추정 마찰력 값을 의미하며, 본 발명의 마찰보상 시스템(10)에 의해 연산되는 제어입력 토크 값은 상기 마찰모델에 의해 추정되는 마찰력 값

을 포함한다. 결과적으로 로봇 동역학은 수정된 제어입력에 따라 다음의 식 4와 같이 수정된다.here,

represents a frictional force value estimated by a friction model in the calculation unit 500 according to an embodiment of the present invention. That is, it means the estimated frictional force value to be calculated for friction compensation, and the control input torque value calculated by the friction compensation system 10 of the present invention is the frictional force value estimated by the friction model.

includes As a result, the robot dynamics are modified as shown in Equation 4 according to the modified control input.

[Equation 4]

를 만족하면, 마찰의 영향을 제거할 수 있고 사용자는 손쉽게 로봇을 교시할 수 있다. At this time, the frictional force value and the estimated frictional force value calculated are

is satisfied, the effect of friction can be removed and the user can easily teach the robot.

가 가해지지 않은 상황에서도 로봇이 스스로 움직일 수 있다. 이는 로봇이 스스로 에너지를 만들어 낸다는 것을 의미하고, 입력된 에너지 대비 출력되는 에너지가 더 크다는 것을 의미하게 되어 결과적으로 수동성 이론을 위반한다. However, if the friction compensation is applied incorrectly, the user's safety may not be guaranteed while teaching the robot. For example, when overcompensation occurs

The robot can move on its own even in situations where no force is applied. This means that the robot generates energy by itself, and it means that the output energy is greater than the input energy, resulting in a violation of the passivity theory.

을 연산하는 방법에 대하여 설명한다. Accordingly, the passivity-based friction compensation method performed in the calculation unit 500 according to an embodiment of the present invention will be described in detail. Estimated frictional force values to ensure the stability of the robot in more detail

How to calculate is described.

An algorithm built in the calculation unit 500 according to an embodiment of the present invention may use a LuGre friction model. The LuGre (Lund Grenoble) friction model is the most commonly used friction model, and since the basic concept thereof is obvious to those skilled in the art to which the present invention belongs, a detailed description thereof will be omitted.

Equations 5 to 7 below may be applied to the LuGre friction model according to an embodiment of the present invention. On the other hand, a proof process similar to the following can be applied to other friction models other than the LuGre friction model.

[Equation 5]

[Equation 6]

[Equation 7]

는 점성마찰을 나타내며

는 접촉면 돌기의 강성을 나타낸다.

와

는 각각 미시적, 거시적 점성 상수(계수)를 의미하고

와

는 각각 쿨롱 마찰력과 정지 마찰력을 나타낸다.

는 스트라이벡(stribeck)속도를 의미한다. 위와 같은 매개변수는 전술한 바와 같이, 본 발명에 의한 식별부(400)에 의해 산출된 특성 값인 제1매개변수일 수 있다.here,

represents the viscous friction

represents the stiffness of the asperity of the contact surface.

Wow

Means microscopic and macroscopic viscosity constants (coefficients), respectively,

Wow

denotes the Coulombic frictional force and the static frictional force, respectively.

is the stribeck speed. As described above, the above parameter may be the first parameter, which is a characteristic value calculated by the identification unit 400 according to the present invention.

와

는 마찰모델의 일반적인 동역학적 거동을 나타내기 위해서 속도의 함수로 표현되는 것일 수 있다. 이때, 상기

와

에는 아래의 식 8 및 9와 같은 값이 적용될 수 있다.On the other hand, the parameters of the LuGre friction model according to an embodiment of the present invention

Wow

may be expressed as a function of speed to represent the general dynamical behavior of the friction model. At this time, the

Wow

Values such as Equations 8 and 9 below may be applied to

[Equation 8]

[Equation 9]

Hereinafter, it will be described that the friction variable calculated in the algorithm of the calculation unit 500 according to the above-described embodiment of the present invention guarantees the passivity of the cooperative robot during direct teaching.

To this end, the energy (E) of the robot and the estimated friction can be defined as shown in Equation 10 below.

[Equation 10]

은

의 함수이며

,

,

은

의 함수이지만 간편성을 위해 생략한다.At this time, in order to examine the rate of change of energy, the following Equation 11 is derived by performing the differentiation of Equation 10 above. here,

silver

is a function of

,

,

silver

, but omitted for simplicity.

[Equation 11]

) 대비 로봇의 출력(

)이 시스템이 생성하는 에너지 변화보다 항상 크다는 것을 알 수 있고, 이는 곧 본 발명의 일 실시예에 의한 마찰보상 시스템(10)은 직접교시간 시스템의 수동성을 보장한다는 것을 의미한다.Accordingly, if the friction variable is set to satisfy the condition of Equation 12 below, the user input (

) versus the output of the robot (

) is always greater than the energy change generated by the system, which means that the friction compensation system 10 according to an embodiment of the present invention guarantees the passivity of the direct learning system.

[Equation 12]

On the other hand, passivity guarantees the stability of the system, but it does not mean the unconditional safety of the user.

Accordingly, the friction compensation system 10 of the multi-degree-of-freedom robot (A) according to another embodiment of the present invention adds an algorithm for limiting speed and acceleration during direct teaching to ensure the user's convenience in direct teaching and at the same time to ensure the user's safety. It is characterized by securing.

That is, the sensor unit 200 according to an embodiment of the present invention obtains the velocity or acceleration value in each axis of the multi-DOF robot (A) according to the user's direct teaching, and the calculation unit 500 is the sensor unit Based on the speed or acceleration value obtained from (200), an algorithm for limiting the speed in each axis of the multi-degree-of-freedom robot (A) within a predetermined range may be further embedded.

Hereinafter, a friction compensation method for a multi-degree-of-freedom robot according to another embodiment of the present invention will be described with reference to FIG. 4 . A friction compensation method for a multi-degree-of-freedom robot according to various embodiments of the present invention described below may correspond to and apply various embodiments of a friction compensation system for a multi-degree-of-freedom robot described above.

4 is a flowchart showing each step of a method for performing friction compensation of a multi-degree-of-freedom robot (A) according to an embodiment of the present invention in sequence.

As shown, the method for compensating friction of a multi-DOF robot according to an embodiment of the present invention includes a detection step (S10) of acquiring state information values in each axis of the multi-DOF robot; An identification step (S20) of identifying occurrence of friction using the state information value; A calculation step (S30) of calculating a control input value by calculating parameters of the friction model; And a control step (S40) of controlling the motor driving of each axis of the multi-degree-of-freedom robot may be included as a step constituting the basic configuration of the method.

The detection step (S10) according to the present invention may be performed through a sensor device installed to measure the state information value generated in each joint axis of the multi-degree-of-freedom robot (A).

At this time, the state information value obtained in the detection step (S10) according to an embodiment of the present invention may be a dynamic and/or kinematic state information value in each axis of the multi-DOF robot according to the user's direct teaching. In more detail, the detecting step (S10) may be to acquire one or more of the position, speed, temperature, and weight of each axis of the multi-degree-of-freedom robot as a state information value.

In the identification step (S20) according to the present invention, friction occurrence in each axis of the multi-degree-of-freedom robot (A) is identified using the obtained kinematic and/or dynamic state information values. More specifically, a characteristic value in each axis of the multi-degree-of-freedom robot (A) is obtained using the kinematic and/or dynamic state information value. At this time, the obtained characteristic value may be applied as a first parameter to a friction model in the calculation step (S30) described later.

At this time, the first parameter calculated in the identification step (S20) according to an embodiment of the present invention, that is, the characteristic value, is the stiffness, viscosity, frictional force and stribeck at each axis contact surface of the multi-degree-of-freedom robot (A) It may be any one or more of information values about speed.

In the calculation step (S30) according to the present invention, a friction model is built based on the characteristic values for the joint axes of the multi-degree-of-freedom robot (A), which is built in to calculate friction model variables that satisfy the passivity theory. It can be done by an algorithm. Drive and energy output of the joints of the multi-DOF robot (A) are controlled according to the control input value calculated by the algorithm.

At this time, the algorithm of the calculation step (S30) calculates the second parameter using the friction model preset to use the first parameter described above, and the second parameter is input in the robot system system to which the present invention is applied. It is characterized in that it is a value that calculates a control input value that allows energy smaller than the energy to be output.

In the control step (S40) according to an embodiment of the present invention, the calculated control input value is received and a driving control command for each axis motor device of the multi-DOF robot (A) is generated. Specifically, it is possible to control the energy output from the system of the multi-degree-of-freedom robot (A) to which the present invention is applied by generating a control command for supplying power to the motor device, rotational force, and the like.

At this time, since the control step (S40) generates a control command for the motor device according to the control input value calculated in the above-described calculation step (S30), the multi-degree-of-freedom robot (A) to which the present invention is applied is embedded in the system system. It is possible to ensure the passivity of the system regardless of the energy of the motor device.

The algorithm based on the friction model built in the calculation step (S30) according to an embodiment of the present invention can be applied in correspondence with the algorithm based on the friction model built into the calculation unit 500 according to the above-described embodiment of the present invention. Therefore, redundant descriptions thereof will be omitted.

On the other hand, passivity guarantees the stability of the system, but it does not mean the unconditional safety of the user.

Accordingly, the friction compensation method of the multi-degree-of-freedom robot (A) according to another embodiment of the present invention is characterized by adding an acceleration limiting algorithm to ensure the user's direct teaching convenience and at the same time secure the user's safety.

That is, in the detection step (S10) according to an embodiment of the present invention, the velocity or acceleration value in each axis of the multi-degree-of-freedom robot (A) according to the user's direct teaching is obtained, and the calculation step (S30) is the obtained Based on the velocity or acceleration value, an algorithm for limiting the velocity in each axis of the multi-degree-of-freedom robot A within a predetermined range may be further embedded.

According to the above-described embodiments, the friction compensation system and method of the present invention can set friction parameters and compensate the frictional force of joints to ensure direct teaching passivity of the cooperative robot. In addition, it can be applied to the mass production stage of cooperative robots including this to provide a consistent and improved direct teaching function.

Those skilled in the art to which the present invention pertains will understand that the present invention can be embodied in other specific forms without changing its technical spirit or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention. do.

A: Multi-degree-of-freedom robot
10: friction compensation system
100: motor unit
200: sensor unit
300: control unit
400: identification unit
500: calculation unit

Claims (16)

In the friction compensation system of the multi-degree-of-freedom robot,
A motor unit providing driving force to each axis of the multi-degree-of-freedom robot;
A sensor unit for acquiring state information values in each axis of the multi-degree-of-freedom robot according to a user's direct teaching;
an identification unit that detects a characteristic value using the state information value to identify friction and calculates a first parameter;
a control unit generating a control command for the motor unit; and
An algorithm for calculating a second parameter of a friction model using the first parameter is embedded, and a calculation unit for calculating a control input value for the control unit using the second parameter is included,
The sensor unit acquires velocity or acceleration values in each axis of the multi-degree-of-freedom robot according to the user's direct teaching,
The calculation unit calculates the second parameter using the velocity or acceleration value obtained from the sensor unit as a parameter so that energy output from the friction compensation system during direct teaching is smaller than energy input to the friction compensation system, A friction compensation system for a multi-DOF robot, characterized in that an algorithm for limiting the speed in each axis of the multi-DOF robot within a predetermined range is further built-in. delete According to claim 1,
The sensor unit acquires dynamic and kinematic state information values in each axis of the multi-DOF robot according to a user's direct teaching. According to claim 1,
The sensor unit acquires at least one of the position, speed, temperature, and weight of each axis of the multi-DOF robot as a state information value, the friction compensation system of the multi-DOF robot. According to claim 4,
The identification unit calculates and obtains any one or more of information values for stiffness, viscosity, frictional force, and stribeck speed as a first parameter from the state information value. Friction of the multi-degree-of-freedom robot reward system. According to claim 4,
The calculation unit is a friction compensation system for a multi-degree-of-freedom robot, characterized in that an algorithm to which the LuGre friction model is applied is embedded. According to claim 6,
The friction compensation system for a multi-degree-of-freedom robot, characterized in that the LuGre friction model includes, as a parameter, a function having the velocity of the joint axis of the multi-degree-of-freedom robot obtained from the sensor unit as a variable. delete In the friction compensation method of a multi-degree-of-freedom robot,
A detection step of acquiring state information values in each axis of the multi-degree-of-freedom robot;
an identification step of identifying occurrence of friction using the state information value;
A calculation step of calculating a control input value by calculating parameters of the friction model; and
A control step of controlling motor driving of each axis of the multi-degree-of-freedom robot;
The detecting step obtains the velocity or acceleration values in each axis of the multi-DOF robot according to the user's direct teaching,
In the calculating step, based on the obtained velocity or acceleration value, parameters of the friction model are calculated such that energy output from the robot system in which friction compensation is performed during direct teaching is smaller than energy input to the robot system in which friction compensation is performed. Thus, an algorithm for limiting the speed in each axis of the multi-degree-of-freedom robot within a predetermined range is further performed. delete According to claim 9,
In the detecting step, dynamic and kinematic state information values of each axis of the multi-DOF robot according to a user's direct teaching are obtained. According to claim 9,
In the detecting step, one or more of position, speed, temperature, and weight in each axis of the multi-DOF robot is obtained as a state information value. According to claim 12,
In the identification step, from the state information value, any one or more of the information values for stiffness, viscosity, frictional force and Stribeck speed is calculated and obtained as a parameter. According to claim 9,
The algorithm in the calculation step is a friction compensation method for a multi-degree-of-freedom robot, characterized in that the LuGre friction model is applied. According to claim 14,
The friction compensation method for a multi-degree-of-freedom robot, characterized in that the LuGre friction model includes, as a parameter, a function whose variable is the speed of the joint axis of the multi-degree-of-freedom robot.


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