CN103179692A - Human motion tracking system based on Zigbee/ institute of electrical and electronic engineers (IEEE) 802.15.4 - Google Patents

Abstract

Provided is a human motion tracking system based on Zigbee/ institute of electrical and electronic engineers (IEEE) 802.15.4. A wireless wearable sensing network is covered on nine independent limbs of a person, and a wireless wearable sensing node is adhered onto each independent limb for monitoring free motion of the limb in the three-dimensional space. In each wireless wearable sensing node, an inertia measuring unit which comprises a three-axis acceleration sensor, a three-axis gyroscope and a three-axis magnetic force sensor is used for calculating the position of the independent limb in the three-dimensional space through an on-line data infusion calculation method. In the wearable wireless sensing network, real-time location data can be transmitted to a substation through the low-consumption wireless communication technology Zigbee/IEEE 802.15.4. The substation forwards the obtained wireless wearable sensing network to a computer in real time. Human motion can be reconstructed in the computer according to a forward motion model. The reconstructed human motion can be transmitted to a remote user through the internet for tememedicine. The human motion tracking system totally eliminates ligature between sensor nodes, do not need a light source for assisting and facilitates system expansion and application development by means of the low-consumption wireless operation system.

Description

Human motion tracing system based on ZigBee/IEEE802.15.4

Technical field

The present invention relates to a kind of human motion tracing system based on ZigBee/IEEE 802.15.4, refer in particular to a kind of motion tracking method and system that utilizes wearable wireless sense network to move with human body, belong to field of human-computer interaction.

Background technology

Along with the extensive use of computer graphics techniques, the motion tracking technology becomes the focus of research.The human motion tracer technique is medical treatment, the important Research Prospects of rehabilitation field, by remote doctor, and diagnosis and help that patient need not to go out and just can obtain the doctor.In addition, this technology can also be applied to control operation etc. under production of film and TV, training athlete, smart media, hazardous environment.

Realize that at present the technology that human motion is followed the trail of mainly comprises mechanical type tracking, electromagnetic type tracking, video frequency tracking, optical tracking and inertia tracking.The characteristics of mechanical type tracer technique are to calculate accurately, but due to the large very flexible of equipment volume, thereby affect tested object or testee's freedom of motion; The flexibility of electromagnetic type tracer technique is strong, and shortcoming is the impact that easily is subject to magnetic field or other metal objects; The flexibility of video frequency tracking and optical tracking technology is all very strong, and calculates accurately, and shortcoming is the impact that these two kinds of technology easily are subject to natural environment, and cost is higher.

Along with the continuous maturation of MEMS technology, the MEMS inertial sensor is applied to the motion tracking field more and more.Inertial Measurement Unit is present motion tracking field measuring technique commonly used, comprises 3-axis acceleration sensor, three-axis gyroscope and three axle magnetometers.The motion that a certain rigid body can only be followed the trail of in use single-measurement unit, following the trail of for human motion needs 15 nodes at least.These enabling communication between nodes can be selected wired and wireless dual mode.Wire communication needs all nodes are connected to centralized control unit CCU (central control unit), and flexibility is very poor, and radio communication is more flexible, but has increased the complexity of the communication technology.In the prior art, utilize Inertial Measurement Unit to carry out the method that human motion follows the trail of a lot, but the function of node only limit to gather exercise data, relevant task scheduling, the tasks such as progress arrangement all depend on the base station.

Summary of the invention

The present invention proposes a kind of human motion tracing system based on ZigBee/IEEE 802.15.4, purpose is to utilize a plurality of Inertial Measurement Units to form wearable radio sensing network acquisition process body motion information, and accuracy is high, real-time good, communication is stable, the human motion tracing system of low-power consumption thereby build one.

For overcoming the defective of existing human motion tracing system, the technical solution adopted for the present invention to solve the technical problems is:

A kind of human motion tracing system based on ZigBee/IEEE 802.15.4 is realized by wearable radio sensing network, wearable radio sensing network is used for gathering body motion information and passes through the low-consumption wireless communication technology, be transmitted to computer, utilize virtual reality technology to present in real time 3 d human motion.

Described wearable radio sensing network comprises a plurality of wearable sensor nodes and a base station.Wearable sensor node is distributed in respectively each position of human body.The base station is transmitted to computer by USB interface with movable information.

Described wireless wearable sensing node comprises 3 kinds of transducers: 3-axis acceleration sensor, three-axis gyroscope and three axle magnetometers.Node carries out multi-task scheduling by embedded micro operation system, adopts the isomeric data blending algorithm to calculate the human motion orientation, and sends to the base station by low-consumption wireless communication protocol, simultaneously from the base station receiving control information.

Described micro operation system is TinyOS-1.x.

Described low-consumption wireless communication protocol is ZigBee/IEEE 802.15.4.

Described isomeric data blending algorithm is Kalman filtering algorithm.

Described base station receives the human action information of wearable sensor node collection and is transmitted to computer and processes, and sends control information to each sensor node simultaneously.

In order to solve the problem of human motion tracing system real-time, adopt the method for time division multiple access TDMA (time division multiple access) to realize real-time tracing.

The present invention adopts the human motion tracing system based on ZigBee/IEEE 802.15.4 of above device, comprises following five steps:

Step 1: placement sensor node: the both arms (left/right forearm, left/right upper arm each 1, totally four), both legs (leg on left/right, left/right shank each 1, totally four) and the belly that nine wearable sensor nodes are fixed on the testee;

Step 2: acquisition process body motion information: all are wireless, and wearable sensing node gathers monitored componental movement information and does Data Fusion, obtains the dimensional orientation data;

Step 3: send data: the data after nine wireless wearable sensing nodes will be processed send to the base station according to the TDMA time division multiplexing mode;

Step 4: receive data: the base station receives the data that wireless wearable sensor network sends and is transmitted to computer;

Step 5: three-dimensional reconstruction stereoscopic motion: computer is received the data that wireless wearable sensing network sends, and utilizes the propulsion model, the reconstruct human motion, and present in real time.

Be compared with the prior art, advantage of the present invention is as follows:

(1) adopt the human motion tracing system based on wireless wearable sensing network of the present invention, eliminate the line constraint between sensing node, facilitate human body in the three dimensions free movement, flexibility is good.

(2) utilize the low-consumption wireless communication technology (as ZigBee/IEEE 802.15.4), make each wireless wearable sensing node have high energy efficiency, extend the use lifetime of node.

(3) each wireless wearable sensing node of the present invention adopts Inertial Measurement Unit to measure independent limb motion, does not need light source, satisfies the sporter and uses in without luminous environment.

(4) in the present invention in wireless wearable sensing node, utilize low-power consumption operating system, facilitate multitasking and scheduling, increased system flexibility and autgmentability, be convenient to the exploitation of System Expansion and new business.

Description of drawings

Fig. 1 human body machinery physiological models

Fig. 2 is based on wireless wearable sensing network human motion tracking system architecture figure

The wearable sensor node structure chart of Fig. 3

Execution mode

Fig. 1 is the Human Physiology mechanical model, can be divided into 15 independently limbs based on this model human body, and each limbs has six-freedom degree in three dimensions.Thereby each limbs can utilize an Inertial Measurement Unit with six degree of freedom to follow the trail of the motion of these limbs in three dimensions.

Figure two is based on the system architecture diagram of wireless wearable sensing network, based on the human motion tracing system of ZigBee/IEEE 802.15.4 by wearable wireless sensing node, wireless wearable sensing network, base station (or gateway, books mark with gateway, and this paper is referred to as with the base station) and distributing network four parts compositions.Wireless wearable node is used for each independent limbs of monitoring in the motion of three dimensions; Wireless wearable sensing network is used for monitoring whole human motion; The base station is used for reception and comes from the real-time low power consumption data of wireless wearable sensing network, and carries out human motion reconstruct in this locality; Distribution networks is mainly used in attitude data distribution in real time on the internet, is convenient to remote monitoring or medical treatment.

Nine wearable wireless sensing nodes of wearable radio sensing network bag and 1 base station in the present invention.Nine wearable sensing nodes are distributed in respectively thigh and shank and the belly of the upper arm of human body both arms and forearm, both legs.The base station is transmitted to computer by USB interface with movable information.

As shown in Figure 3, each wearable sensor node comprises three kinds of transducers and a high accuracy microprocessor: a 3-axis acceleration sensor 111, a three-axis gyroscope 112, three axle magnetometers 113 and a microprocessor 114.3-axis acceleration sensor, three-axis gyroscope and three axle magnetometers consist of the inertance element with six degree of freedom, can obtain independent limbs in the three dimensions any means.This orientation is calculated by microprocessor, obtains to be used for describing three dimensional orientation description value Eulerian angles or four-tuple.In each wearable sensing node, adopt low-power consumption operating system TinyOS-1.x, be responsible for sensor data acquisition, position of orientation calculating and multinode wireless communication technology.Calculate the dimensional orientation data, and send to the base station by the ZigBee/IEEE802.15.4 agreement, simultaneously from the base station receiving control information.

In the present invention, wearable sensor node adopts the Imote2 wireless sensing node of Crossbow company, has 32-bit microprocessor, and operating frequency is at 13～416MHz.The transducer plate adopts the VN100 of VectorNA company, and 32 built-in 8-digit microcontrollers are responsible for the processes sensor sampling and are carried out the spreading kalman algorithm, and highest frequency can reach 200Hz.

Because the human motion tracking is higher to requirement of real time, so the present invention adopts the method for time division multiple access TDMA (time division multiple access) to guarantee multinode reliable communication in wireless wearable sensing network.In the TDMA implementation procedure, because low-power consumption operating system Tinyos adopts first the first mode of service, thereby time synchronized adopts the mode dispatch one by one each sensor node to realize, when namely first wearable node sent data, second node monitored this node; After first node is sent, enter resting state, second node begins to send data.Once analogize, until that nine nodes all send data is complete.

In the delay of the processing delay of not considering operating system and base station and computer, be approximately 3.225 milliseconds the time of delay of each sampling.Wearable wireless sensing node system clock was 46.2 nanoseconds, and it is approximately 1.107 milliseconds that system call postpones.Define 5 milliseconds of each tdma system time slots, and definition of T DMA frame length is 10, namely 50 milliseconds, thus the highest refreshing frequency of system motion is 20 hertz.

In sum, the present invention is based on the human motion tracing system of ZigBee/IEEE 802.15.4, comprise following five steps:

Step 1: placement sensor node: the both arms, both legs and the belly that nine wearable wireless sensing nodes are fixed on the testee;

Step 2: acquisition process body motion information: wearable wireless sensing node gathers each limb motion information and does Data Fusion, obtains the three dimensional orientation data;

Step 3: send data: wireless all nodes of wearable sensing network send to the base station to the data of each limbs according to the TDMA mode;

Step 4: receive data: the base station receives the data of wireless wearable network all the sensors node transmission and is transmitted to computer;

Step 5: three-dimensional reconstruction human motion: based on the propulsion model, the reconstruct human motion, utilize virtual reality technology in a frame time, realizes that three-dimensional presents.

The present invention is based on based on the human motion tracing system of ZigBee/IEEE 802.15.4 simple to operately, follow the trail of precision high, real-time, utilize wireless communication mode, make testee's freedom of movement, improve system flexibility.Utilize the mode of the embedded micro operation system of Inertial Measurement Unit to carry out task scheduling, save time, reduced complexity and the energy consumption of whole system, extend the life cycle of the energy.

Claims (8)

1. the human motion tracing system based on ZigBee/IEEE 802.15.4 is comprised of wireless wearable sensor node, wireless wearable sensing network, base station and distributing network four parts.Wireless wearable Sensor Network is used for gathering human action information, and human body movement data information is transmitted to computer, utilizes virtual reality technology to realize that the 3 D human body action reappears.

2. the human motion tracing system based on ZigBee/IEEE 802.15.4 according to claim 1, is characterized in that utilizing Inertial Measurement Unit to gather body motion information as wearable sensor node.

3. the human motion tracing system based on ZigBee/IEEE 802.15.4 according to claim 1, is characterized in that wearable radio sensing network comprises nine wearable sensor nodes and a base station.Nine wearable wireless sensor nodes are distributed in respectively thigh and shank and the belly of the upper arm of human body both arms and forearm, both legs.The base station is transmitted to computer by USB interface with movable information.

4. the human motion tracing system based on ZigBee/IEEE 802.15.4 according to claim 1, is characterized in that described wireless wearable sensor node, comprises three axle acceleration sensors, a three-axis gyroscope and three axle magnetometers.

5. the human motion tracing system based on ZigBee/IEEE 802.15.4 according to claim 1, is characterized in that node carries out multi-task scheduling by the TinyOS-1.x micro operation system with first in first out, as data sampling, radio communication etc.

6. the human motion tracing system based on ZigBee/IEEE 802.15.4 according to claim 1, it is characterized in that adopting in node expanded Kalman filtration algorithm to carry out online data to 3-axis acceleration, gyroscope and three axle magnetometers merges, obtain the three dimensional orientation data, and send to the base station by the low-consumption wireless communication technology, simultaneously from the base station receiving control information.

7. wireless communication protocol according to claim 6 is characterized in that using ZigBee/IEEE 802.15.4 agreement, and the system of assurance has the long lifetime.

8. the human motion tracing system based on ZigBee/IEEE 802.15.4 according to claim 1 is characterized in that comprising following five steps:

Step 1: placement sensor node: the both arms, both legs and the belly that nine wireless wearable sensor nodes are fixed on the testee;

Step 2: acquisition process body motion information: wireless wearable sensor node gathers testee's movable information and does Data Fusion;

Step 3: send data: the data after wireless wearable sensor node will be processed send to the base station;

Step 4: receive data: the base station receives the data of wireless wearable sensor node transmission and is transmitted to computer;

Step 5: three-dimensional reconstruction stereoscopic motion: according to the Forward kinematics principle, utilize virtual reality technology to rebuild human action information.

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