KR20150117556A - Apparatus for walk imitation control of biped robot - Google Patents

Abstract

The present invention relates to a walk imitation control device for a biped robot capable of measuring the movement of worker′s joints using a wearable sensor, grasping the center of the pressure (COP) of the robot using a sole sensor, and thereafter imitation-controlling a walk of the biped robot based on the measurement and the COP. The present invention provides the walk imitation control device for the biped robot including a track data generator detecting data of each joint according to the movement of the joint of the worker, computing the COP data generated based on the detected sole pressure of the biped robot and the joint data, and thereafter generating track data for movement imitation; a robot controller controlling a walk of the biped robot based on the track data generated by the track data generator; and the biped robot imitating the movement of the worker according to the control of the robot controller.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a biped walking robot,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to walking imitation control of a biped robot, and more particularly, to a walk imitation control of a biped robot, which measures movement of an operator's joint using a wearable sensor, A bipedal walking robot having a bipedal walking robot and a bipedal walking robot, the bipedal walking robot having a pressure center secured thereto and imitating and controlling the walking of the bipedal walking robot.

Robot applications are increasing. Generally, robots do simple and dangerous work on behalf of humans. For example, a robot is used in a simple assembly process in a manufacturing plant. In addition, robots can be used for deep sea exploration, where humans are hard to reach, and they can replace humans in explosive dismantling.

In recent years, research on the development of bipedal humanoid robots (robots with a similar appearance to the human body) has been conducted. Robot and technology development is progressing close to human figure, facial expression and gait. Honda ASIMO is the most representative example. Although research on the development of bipedal walking humanoids is underway worldwide, the intelligence of humanoids is still too low for smart work. The humanoid itself is still too early to be smart enough to think and decide.

There is a growing need to control bipedal humanoids by humans. As a result, human control bipedal humanoids can work on behalf of humans in places where human access is difficult, such as a disaster scene. Human control bipedal robots develop smart enough to do smart work because it is controlled by human intelligence. While these robots are attractive, reaching this level still requires much research.

There have been several attempts to operate bipedal robots. A remote controller (RC) was used for bipedal walking robot but it was found that the limit of motion control and the degree of freedom (DOF) were low. Keio University announced that it can control a bipedal walking robot by recognizing a touch input of a gesture similar to that used in a touch-screen smartphone (see Non-Patent Document 1 below). A Senior and Sabri Tosunoglu disclosed a method of controlling a bipedal walking robot by transmitting commands to a bipedal walking robot from a computer having a serial communication connection (see Non-Patent Document 2 below) Reference). In addition, Bluetooth was used for remote control of biped robot.

As another research area, human imitation control methods are being studied. The imitation control tracks the motion trajectory of the human operator and transmits it to the robot, which makes the robot move like a human operator. In addition, imitation control for biped walking robots has emerged as a new research problem.

To track the trajectory of human motion, the gyroscope and acceleration sensor are attached to specific parts of the body. T. Liu and colleagues showed that the gait estimation was estimated by applying a fuzzy inference engine to measurement data of angular velocity and acceleration (see Non-Patent Documents 3 and 4 below). Ude measured joint angles using a magnetic mark system (see Non-Patent Document 5 below). Some inertial sensor systems are also used to measure the lower body part orientation (see Non-Patent Document 6 below). R. Chalodhorn and colleagues say that it is more flexible and intuitive to use motion capture data directly than program control, although it is unstable in the dynamic sense (see Non-Patent Document 7 below). As another example, a three-dimensional real-time human motion capture system using a force sensor and a hand tracking device is proposed as a whole body motion reconstruction (refer to Non-Patent Document 8 below).

Keio University, Walky project, Graduate School of Media design, Nov. (2009). Andre Senior and Sabri Tosunoglu, "Design of a Biped Robot", Florida Conference on Recent Advances in Robotics, FCRAR (2006). T. Liu, H. Utsuomiya, Y. Inoue, and K. Shibata, "Synchronous Imitation Control for Biped Robot Based on Human Motion Analysis System", 2008 IEEE / RSJ International Conference on Intelligent Robots and Systems, France, Sep. 22-26, (2008). T. Liu, Y. Inoue, K. Shibata, and H. Morioka, "Development of Wearable Sensor Combinations for Human Lower Extremity Motion Analysis", 2006 IEEE International Conference on Robots and Automation, Florida, May. (2006). Ude, A. etal. "Automatic generation of kinematic models for the conversion of human motion capture data into humanoid robot motion", In Proc. First IEEE-RAS Int. Conf. Humanoid Robots, (2000). Tao Liu, Y. Inoue, and K. Shibata, "Imitation Control for Biped Robot Using Wearable Motion Sensor ", Journal of Mechanisms and Robotics, May, Vol. 2, (2010). R. Chalodhorn, et al, "Learning to Walk Through Imitation", Twentieth International Joint Conference on Artificial Intelligence, India, Jan. 6-12, (2007). Sehoon Ha, Y Bai, and C. Karen Liu, "Human Motion Reconstruction from Force Sensors", ACM SIGGRAPH Symposium on Computer Animation, (2011). Hsin-Yu Liu, Wen-June Wang, Rong-Jyue Wang, Cheng-Wei Tung, Pei-JuiWang, and I-Ping Chang, "Image Recognition and Force Measuring Application in Humanoid Robot Imitation", IEEE Trans. On Instrumentation and Measurement, Vol. 61, No. 1, Jan., (2012).

However, the above-mentioned prior art attempts to study imitation control, but most of these studies do not provide a result of actual robot walking. It merely suggests that in a virtual space, robots mimic worker movements very much. Although there are many types of sensor systems for tracking the movements and joints of human operators, these systems can be used in a variety of applications such as optical tracking (see <Non-Patent Document 9>), magnetic marking, acceleration sensors, Since only one calculation is applied to one value, it is not a method to directly use the motion of the robot, so it can not be regarded as direct walking imitation control.

It is an object of the present invention to solve the above-mentioned problems in the prior art. The present invention provides a robot that measures a movement of an operator's joint using a wearable sensor and secure the pressure center of the robot through a sole sensor And to provide a bipedal walking controller of a bipedal walking robot capable of imitating and controlling walking of a bipedal walking robot on the basis thereof.

Another object of the present invention is to provide a bipedal walking controller of a bipedal walking robot in which each movement of all the joints of an operator is directly tracked and applied to the walking imitation control so as to improve the accuracy of the walking imitation control.

Another object of the present invention is to provide a bipedal walking robot control apparatus for bipedal robot which implements imitation control on an actual robot based on static walking using a pressure center of a bipedal walking robot so that the robot can be controlled in real time according to an operator's intention .

In order to achieve the above object, the walking / mimic controller of a biped walking robot according to the present invention detects joint angle data in accordance with a movement of an operator's joint, detects joint angle data and foot pressure of the biped walking robot A locus data generator for generating locus data for motion imitation by computing pressure center (COP) data generated through the locus data; A robot controller for controlling the walking of the bipedal walking robot based on the locus data generated by the locus data generator; And the bipedal walking robot for mimicking the movement of the operator under the control of the robot controller.

Wherein the locus data generator comprises: a wearable sensor for detecting joint angle data according to a movement of an operator's joint; A sole pressure sensor for detecting the sole pressure of the biped walking robot to generate pressure center data; And a data calculator for calculating the joint angle data of the wearable sensor and the pressure center data of the plantar pressure sensor and outputting the calculated results as walking trajectory data.

Preferably, the wearable sensor includes a strap for attaching to a joint part of an operator; A rod connected to the strap and moving according to movement of the operator's joint; A resistance type rotary encoder for detecting movement of the rod as a joint angle signal; A shaft for connecting the load to the resistive rotary encoder; And a data processing module for processing the output signal of the resistance type rotary encoder to generate joint angle data.

The data processing module includes an analog / digital converter for converting the output signal of the resistive rotary encoder into a digital signal; A microprocessor for searching a joint data table stored in advance in an internal memory with an index of the digital signal output from the analog / digital converter and converting the detected signal into joint angle data; And an output port for outputting joint angle data output from the microprocessor.

The foot pressure sensor comprises: a pressure measuring unit attached to the sole of the biped walking robot for measuring the sole pressure; And a data processing module for generating pressure center data according to the posture change of the robot based on the plantar pressure measurement signal measured by the pressure measuring unit.

The pressure measuring unit includes a frame; And a plurality of tactile pressure sensors mounted on respective corners of the frame for measuring the plantar pressure of the bipedal walking robot.

Wherein the data processing module includes: an analog-to-digital converter for converting a position-based pressure signal output from the plurality of tactile-pressure sensors of the pressure measuring unit into digital pressure data; A microprocessor for calculating pressure center data based on a variation amount of a plurality of pressure data output from the analog / digital converter; And an output port for outputting pressure center data calculated by the microprocessor.

The data calculator subtracts the pressure center data output from the plantar pressure sensor from the joint angle data output from the wearable sensor, and outputs the result as the walking locus data.

According to the present invention, the movement of the operator's joints is directly tracked using a wearable sensor, the pressure center of the robot is secured through the sole sensor, and the walk of the biped walking robot is imitated and controlled based on this, The accuracy can be improved.

In addition, according to the present invention, an imitation control is applied to an actual robot on the basis of a static walking using a pressure center of a biped walking robot, thereby realizing control of the robot in real time as intended by an operator.

FIG. 1 is a conceptual diagram of a walking-mimic controller of a bipedal walking robot according to a preferred embodiment of the present invention,
Fig. 2 is a block diagram of a control system of the walking-mimic controller of the biped walking robot shown in Fig.
Fig. 3 is a configuration diagram of an embodiment of the wearable sensor of Fig. 2,
Fig. 4 is an illustration of wearing of the wearable sensor of Fig. 2 and a walking motion of a biped walking robot according to a movement of an operator,
FIG. 5 is a diagram showing a motion data comparison between biped walking robots according to the angular position of a worker according to the present invention,
Fig. 6 is a block diagram of an embodiment of the sole pressure sensor of Fig. 2; Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a walking / mimic controller of a biped walking robot according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram of a walking / mimic controller of a bipedal walking robot according to a preferred embodiment of the present invention, which includes a locus data generator 100, a robot controller 200, and a biped walking robot 300.

The locus data generator 100 detects the joint angle data according to the movement of the operator's joint and calculates the pressure center (COP) data generated through the detected joint angle data and the plantar pressure of the bipedal walking robot, And generates the locus data.

Here, as shown in FIG. 2, the locus data generator 100 includes a wearable sensor 110 for detecting the joint angle data according to the movement of the operator's joints; A sole pressure sensor 120 for detecting the sole pressure of the biped walking robot 300 to generate pressure center data; And a data calculator 130 for calculating the joint angle data of the wearable sensor 110 and the pressure center data of the plantar pressure sensor 120 and outputting the results as walking trajectory data.

3, the wearable sensor 110 preferably includes a strap 111 for attaching a wearable sensor to a joint part of an operator; A rod 112 connected to the strap 111 and moving according to movement of the operator's joint; A resistive rotary encoder 114 for detecting the movement of the rod 112 as a joint angular signal; A shaft 113 for connecting the resistance rotary encoder 114 and the rod 112; And a data processing module 115 for processing the output signal of the resistance rotary encoder 114 to generate joint angle data.

More preferably, the data processing module 115 includes an analog-to-digital converter 115a for converting an output signal of the resistive rotary encoder 114 into a digital signal; A microprocessor 115b for searching a joint data table stored in advance in the internal memory by using the digital signal outputted from the A / D converter 115b as an index and converting the detected signal into joint angle data; And an output port 115c for outputting the joint angle data output from the microprocessor 115b. Here, the output port 115c may be a communication port, a wired communication port, or a wireless communication port.

As shown in FIG. 6, the foot pressure sensor 120 includes a pressure measuring unit 121 attached to the sole of the biped walking robot 300 to measure the sole pressure. And a data processing module 122 for generating pressure center data according to a posture change of the robot based on the plantar pressure measurement signal measured by the pressure measuring unit 121. [

The pressure measuring unit 121 includes a frame 121a; And a plurality of tactile pressure sensors 121b, 121c, 121d, and 121e mounted on respective corners of the frame 121a to measure the sole pressure of the biped walking robot 300.

Also, the data processing module 122 includes an analog-to-digital converter 122a for converting a position-based pressure signal output from the plurality of tactile-force sensors 121b to 121e of the pressure measuring unit 121 into digital pressure data; A microprocessor 122b for calculating pressure center data based on a variation amount of a plurality of pressure data output from the analog / digital converter 122a; And an output port 122c for outputting pressure center data calculated by the microprocessor 122b. Here, the output port 122c may be a communication port, a wired communication port, or a wireless communication port.

The robot controller 200 controls the walking of the biped walking robot 300 based on the locus data generated by the locus data generator 100.

The biped walking robot 300 imitates the motion of the worker under the control of the robot controller 200.

The operation of the bipedal walking controller of the bipedal walking robot according to the preferred embodiment of the present invention will now be described in detail.

As shown in Fig. 1, the biped walking robot 300 is controlled so that the same movement can be imitated by the operator (operator). To this end, the trajectory data generator 100 acquires the trajectory data according to the movement of the operator and transmits the trajectory data to the robot controller 200. Here, the locus data may include a walker's walking pattern and a walking pattern. Based on the locus data, the robot controller 200 controls the biped walking robot 300 using an actuator.

In order to precisely mimic the biped walking robot 300 in accordance with the movement of the worker and to control it in real time, the movement of the worker's joints must be accurately measured and the mobile walking robot must be controlled through it.

To this end, the trajectory data generator 100 provides joint angles θo1, ..., θom of the operator, which represent the operator's arms, legs and body shapes corresponding to the position angles θr1, ..., θrm of the robot, respectively . In addition, the robot controller 200 controls the stable walking of the biped walking robot 300 by acquiring the pressure center COP through the soles pressure sensor 120.

Theoretically, the imitation control can easily be achieved by copying the joint angle of the operator to the corresponding joint of the robot, as in Equation (1) below. In this case, it is assumed that the data transmission time between the operator and the biped robot is negligible.

The biggest problem in imitating control of a bipedal walking robot is how the robot can walk stably according to the invisible trajectory data. Invisible locus data is continuously input to the robot controller 200. To do so, the robot controller 200 must provide a stable gait algorithm through the entire gait phase.

To this end, the present invention uses the wearable sensor 110 to detect the angular position of each joint of the operator. 3 shows a configuration of the wearable sensor 110 according to the present invention. The wearable sensor 110 includes a resistance rotary encoder 114, a strap 111, and a data processing module 115. The strap 111 is for attaching the wearable sensor 110 to the human joint. Fig. 4 shows an example of attaching the wearable sensor 110 to the human joint using the strap 111. Fig. As the operator moves the joint, the attached wearable sensor 110 generates a joint angular position signal. For example, when the worker moves the pipe, the rod 112 moves in conjunction with the movement of the pipe, and the resistance type rotary encoder 114 works in conjunction with the movement of the rod 112. [ At this time, the resistance varies (increases or decreases) depending on the bending and bending of the joint, and the amount of bending and pin amount of the joint. The joint angular position signal corresponding to the movement of the operator detected in this manner is transmitted to the data processing module 115.

The analog-to-digital converter 115a of the data processing module 115 converts the input analog joint angular position signal into corresponding digital joint angular data, and the microprocessor 115b converts the converted digital signal into an index And searches the joint data table stored in advance in the internal memory to convert the detection signal (joint angle position signal) into joint angle data. The transformed joint angle data is output to the data processor 130 via the output port 115c.

Here, the microprocessor 115b may use an 8-bit Atmel AVR microprocessor (ATmega8A). The ATmega8A chip basically includes 8K bytes of flash program memory and 1K byte internal SRAM. And the resistive rotary encoder 114 is operated with low energy consumption, and it is preferable to use a resistive rotary encoder suitable for gait measurement.

Here, the wearable sensor 110 may be attached to the hip, the thigh, and the knee of the operator, respectively. Through the communication port (output port), the joint angle value is obtained so that it can be used for all sensors.

5 shows a comparison result of some angular movements between the robot joint and the worker's joint. Experimental results show how robots cope well when an operator moves a joint position arbitrarily. Experimental results show that the robot (dotted line) follows the operator well and there is some time delay between the operator and the actuator.

Although the robot joint moves according to the operator's joint, the operator does not know what the robot actually is. A good way to check the state of the robot is to use the concept of pressure center (COP). This is why the sole with the foot pressure sensor 120 for measuring the force between the ground and the sole is mounted on most robots.

FIG. 6 shows the structure of the plant pressure sensor 120 for measuring the pressure center (COP). The foot pressure sensor 120 preferably uses a tactile pressure sensor which is a resistance type pressure sensor. As the attitude of the robot changes, the pressure sensor value also changes, and the measured pressure center also changes.

For example, the pressure measuring unit 121 is attached to the sole of the biped walking robot 300 to measure the sole pressure. The pressure measuring unit 121 includes a frame 121a and a plurality of tactile pressure sensors 121b, 121c, 121d, and 121e for measuring the sole pressure at each corner of the frame 121a. Accordingly, when the robot moves and changes the position of the sole, the pressure of the plurality of tactile pressure sensors 121b, 121c, 121d, and 121e also changes, and the pressure center also changes.

The plant pressure measurement signal measured by the pressure measurement unit 121 is transmitted to the data processing module 122. The data processing module 122 generates pressure center data according to the posture change of the robot based on the measurement signal.

For example, the data processing module 122 converts the position-specific pressure signals output from the plurality of haptic pressure sensors 121b to 121e into digital pressure data in the analog-to-digital converter 122a, And calculates pressure center data based on the amount of change of the plurality of pressure data. That is, when the robot is walking, the pressure of each of the plurality of haptic pressure sensors 121b to 121e is varied. When the pressure values of the four positions are detected, It is possible to know whether the pressure is the lowest, and the pressure center can be calculated based on such pressure information. The pressure center calculation method is preferably a known well-known pressure center calculation method. The calculated pressure center data is transmitted to the data processor 130 via the output port 122c.

Here, the foot pressure sensor is preferably operated by integrating a 32-bit Cortex microcontroller and an incremental pressure sensor. FlexiForce, a thin tactile pressure sensor manufactured by Tekscan Inc, can be used for pressure measurement. The Cortex (myCortex-LM308) chip basically includes 16 Kbytes of flash program memory and 4 Kbytes of internal SRAM.

Next, the data calculator 130 subtracts the pressure center data output from the plantar pressure sensor 120 from the joint angle data output from the wearable sensor 110, and outputs the result as a walking locus data to the robot controller 200 ).

The robot controller 200 controls the walking of the biped walking robot 300 using an actuator on the basis of the transmitted walking trajectory data, whereby the walking imitation control according to the movement of the worker is performed in real time.

According to the present invention, there is an advantage that a movement of a worker can be imitated very precisely in real time and a high degree of freedom can be obtained. The imitation control was applied to the biped walking robot using the developed wearable sensor and algorithm, and it was possible to control the robot according to the operator 's intention by applying the imitation control to the actual robot based on the static walking using the pressure center.

Although the present invention has been described in detail with reference to the above embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

The present invention is effectively applied to a technique of imitating and controlling the walking of a bipedal walking robot.

100: Trajectory data generator
110: wearable sensor
111: strap
112: rod
114: Resistance type rotary encoder
115: Data processing module
120: sole pressure sensor
130: Data calculator

Claims (9)

The joint angle data is detected in accordance with the movement of the operator's joint, the joint center angle data and the pressure center (COP) data generated through the foot pressure detection of the bipedal walking robot are computed to generate locus data for motion mimicry Generator;
A robot controller for controlling the walking of the bipedal walking robot based on the locus data generated by the locus data generator; And
And a biped walking robot that imitates a movement of a worker under the control of the robot controller.
[2] The apparatus according to claim 1, wherein the locus data generator comprises: a wearable sensor for detecting joint angle data according to joint movement of an operator; A sole pressure sensor for detecting the sole pressure of the biped walking robot to generate pressure center data; And a data calculator for calculating the joint angle data of the wearable sensor and the pressure center data of the plantar pressure sensor and outputting the calculated results as walking trajectory data.
[3] The wearable type sensor according to claim 2, wherein the wearable sensor comprises: a strap for attaching the wearable sensor to a joint part of an operator; A rod connected to the strap and moving according to movement of the operator's joint; A resistance type rotary encoder for detecting movement of the rod as a joint angle signal; A shaft for connecting the load to the resistive rotary encoder; And a data processing module for processing the output signal of the resistance type rotary encoder to generate joint angle data.
The data processing module of claim 3, wherein the data processing module comprises: an analog-to-digital converter for converting an output signal of the resistive rotary encoder into a digital signal; A microprocessor for searching a joint data table stored in advance in an internal memory with an index of the digital signal output from the analog / digital converter and converting the detected signal into joint angle data; And an output port for outputting joint angle data output from the microprocessor.
The foot pressure sensor according to claim 2, wherein the foot pressure sensor comprises: a pressure measuring unit attached to the sole of the biped walking robot to measure the sole pressure; And a data processing module for generating pressure center data according to the posture change of the robot based on the plantar pressure measurement signal measured by the pressure measuring unit.
[6] The apparatus of claim 5, wherein the pressure measuring unit comprises: a frame; And a plurality of tactile-force sensors mounted on respective corners of the frame for measuring the plantar pressure of the bipedal walking robot.
[6] The data processing module of claim 5, wherein the data processing module comprises: an analog-to-digital converter for converting a position-specific pressure signal output from the plurality of tactile-pressure sensors of the pressure measuring unit into digital pressure data; A microprocessor for calculating pressure center data based on a variation amount of a plurality of pressure data output from the analog / digital converter; And an output port for outputting pressure center data calculated by the microprocessor.
The walking-mimetic controller of the biped walking robot according to claim 2 or claim 5, wherein the foot pressure sensors are installed on the left and right feet of the bipedal walking robot, respectively.
The biped robot according to claim 2, wherein the data calculator subtracts the pressure center data output from the plantar pressure sensor from the joint angle data output from the wearable sensor, and outputs the result as the walking locus data Walking mimic controller.

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