CN101592947A - Electric wheelchair controller and control method that a kind of Zigbee inserts - Google Patents

Abstract

The invention discloses electric wheelchair controller and control method that a kind of Zigbee inserts, controller comprises master control board, data acquisition board, motor control box and wireless communication module; Wireless communication module is connected with master control board and communicates by letter, and data acquisition board is connected with master control board, and motor control box is connected with master control board.Control method is as follows: (1) acquisition parameter; (2) set up controlling models; (3) set up radio communication; (4) carry out steering order: the parameter of gathering in the step (1) is input to the kinematic parameter that obtains electric wheelchair in the controlling models that obtains in the step (2); Step (3) passes to radio sensing network with the kinematic parameter of electric wheelchair, the motion of the semantic instruction control electric wheelchair that radio sensing network sends.This controller design method has reduced the computational burden of node in the wireless sensor network, and economical and effective also satisfies the requirement of wireless sensor network to electric wheelchair.

Description

Electric wheelchair controller and control method that a kind of Zigbee inserts

Technical field

The present invention relates to belong to wireless sensor network and Robotics field, electric wheelchair controller and method that particularly a kind of Zigbee inserts.

Background technology

Wireless sensor network (Wireless Sensor Network) is to relate to the hot research field, forward position that multidisciplinary height intersects now.It combines sensor technology, modern computer network technologies, embedded computing technique and Distributed Calculation and control technology etc.The node that is distributed in the network carries out the real-time perception and the collection of information by various sensors to surrounding environment, utilize wireless communication module 2 to cooperate between the node, information sharing, knowledge fusion, use Distributed Calculation and control technology, next step behavior of network is made a strategic decision.Wireless sensor network organically merges physical environment and information world, has improved the cognitive environment ability widely, has expanded the application of computational intelligence in actual environment.

Zigbee is the new technology of disposing wireless sensor network.It is a kind of short distance, low rate radio network technique, is a kind of technology motion between radio mark technology and BlueTooth.Zigbee one etymology when finding the pollen position, is informed companion by jumping the dancing of ZigZag shape from hive, reaches the purpose of exchange message.Call a kind of short-range wireless networks communication technology of being absorbed in low-power consumption, low cost, low complex degree, low rate whereby.

Electric wheelchair is the telecontrol equipment that a kind of electrification drives, and is widely used in places such as hospital, convalescence center and old community, for handicapped personage provides a kind of effective walking-replacing tool.Electric wheelchair is inserted wireless sensor network with the Zigbee technology, can utilize the powerful environment sensing ability of network to obtain sufficient navigation information, realize the autokinetic movement of electric wheelchair in environment, thereby bring great convenience for the user.The correlative study of at present domestic relevant electric wheelchair controller design occurs, and part has solved the problem of electric wheelchair motion control, man-machine interaction aspect.The patent of invention CN101214182 " direction speed control device of electric wheelchair " that authorized people such as Guo Yongji in 2008 has proposed a kind of design proposal of electric wheelchair direction speed control device.The focusing on of this scheme installed a kind of measurement mechanism to electric wheelchair, in order to measure the disturbance quantity in the electric wheelchair motion process and to be proofreaied and correct on controller, reaches the purpose of control electric wheelchair direction speed.The patent of invention CN1830413 " a kind of embedded intelligence electric wheelchair control system and method " that authorizes people such as former chief the same year has proposed a kind of design proposal of intelligent control system of electric wheel chair, this scheme is used the obstacle information in the ultrasonic sensor testing environment, realizes that keeping away of electric wheelchair hinders intelligence.

Summary of the invention

The purpose of this invention is to provide electric wheelchair controller and method that a kind of Zigbee inserts.This controller design method is at this specific environment of wireless sensor network, by devices such as wireless communication module 2, sensor are installed to electric wheelchair, insert wireless sensor network and receive semantic instruction with the Zigbee agreement, under the assistance of sensor, realize the motion control of electric wheelchair and keep away function such as barrier.

The electric wheelchair controller that a kind of Zigbee inserts, described controller comprises master control board, data acquisition board 9, motor control box 12 and wireless communication module 2; Wireless communication module 2 is connected with master control board and communicates by letter, and data acquisition board 9 is connected with master control board, and motor control box 12 is connected with master control board; In master control board, also be connected with left infrared switch 1, right infrared switch 3, first ultrasonic sensor 4, second ultrasonic sensor 5, the 3rd ultrasonic sensor 7, the 4th ultrasonic sensor 8 and electronic compass 11; Also be connected with revolver direct current generator 14 and right wheel direct current generator 15 at motor control box 12; Revolver direct current generator 14 is connected with data acquisition board 9 by left code-disc 13, and right wheel direct current generator 15 is connected with data acquisition board 9 by right code-disc 16; The electric wheelchair kinematic parameter that left side infrared switch 1, right infrared switch 3, first ultrasonic sensor 4, second ultrasonic sensor 5, the 3rd ultrasonic sensor 7, the 4th ultrasonic sensor 8, electronic compass 11 and data acquisition board 9 collect is input to master control board, and the rotating speed of revolver direct current generator 14 and right wheel direct current generator 15 is adjusted in master control board by output order; On data acquisition board 9, be connected with gyroscope, the angular speed that the gyroscope survey electric wheelchair rotates.

Described master control board is made of I2C interface, a RS232 interface 18, the 2nd RS232 interface 22, an IO mouth 17, the 2nd IO mouth 19 and the spi bus 20 of CPU and setting around CPU.

(1) acquisition parameter: left infrared switch 1 and right infrared switch 3 detect the barrier around the electric wheelchair; First ultrasonic sensor 4, second ultrasonic sensor 5, the 3rd ultrasonic sensor 7 and the 4th ultrasonic sensor 8 are measured the distance of electric wheelchair and barrier on every side; Electronic compass 11 measure electric wheelchairs definitely towards; Data acquisition board 9 is gathered the rotating speed of revolver direct current generator 14 and right wheel direct current generator 15;

(2) set up controlling models: the kinetic model of setting up the differential driving electric wheelchair of two-wheeled earlier, set up the direct current generator mathematical model again, at last in conjunction with the controlling models of kinetic model with the direct current generator mathematical model acquisition electric wheelchair of the differential driving electric wheelchair of two-wheeled;

(3) set up radio communication: wireless communication module 2 is connected with master control board, master control board inserts radio sensing network by wireless communication module 2, wireless communication module 2 is transmitted to master control board with the semanteme instruction that radio sensing network sends, master control board is resolved semantic instruction and is driven revolver direct current generator 14 and rotates with right wheel direct current generator 15, thus the motion of control electric wheelchair;

(4) carry out steering order: the parameter of gathering in the step (1) is input to the kinematic parameter that obtains electric wheelchair in the controlling models that obtains in the step (2); Step (3) passes to radio sensing network with the kinematic parameter of electric wheelchair, the motion of the semantic instruction control electric wheelchair that radio sensing network sends.

Described step (2) is according to following steps:

(A) kinetic model of the differential driving electric wheelchair of two-wheeled

Two trailing wheels of the differential driving electric wheelchair of two-wheeled are driving wheel, and each drives with a direct current generator; Two other front-wheel is an engaged wheel, supports electric wheelchair and follows rear wheel movement; M is the gross mass of electric wheelchair, and J is the total moment of inertia of electric wheelchair, and r is the driving wheel radius, and l is half of driving wheel spacing, f ₁, f ₂Be the driving force of left and right sidesing driving wheel, v ₁, v ₂Be the linear velocity of left and right sidesing driving wheel, F is the synthetic thrust of electric wheelchair, and τ is the torque of electric wheelchair, and v is the aggregate velocity of electric wheelchair, and ω is the accumulated angle speed of electric wheelchair.According to dynamics formula, following relationship is set up:

$\left\{\begin{array}{c}F=f_1+f_2\\ \mathrm{\τ}=l(f_1-f_2)\end{array}\right.$

$\left\{\begin{array}{c}{v}_1=v+\mathrm{l\ω}\\ v_2=v-\mathrm{l\ω}\end{array}\right.$

$\left\{\begin{array}{c}M\stackrel{\·}{v}=F=f_1+f_2\\ J\stackrel{\·}{\mathrm{\ω}}=\mathrm{\τ}=l(f_1-f_2)\end{array}\right.$

(B) direct current generator mathematical model

The trailing wheel of electric wheelchair is driven by direct current generator; Wherein, reducer casing deceleration g＜1,

Be i dc motor speed, k _mBe the dynamo-electric constant of direct current generator, k _eBe direct current generator electromagnetic constant, E _AiBe i direct current generator electromotive force, R _aBe direct current generator armature resistance, I _iBe i direct current generator armature supply, u _iBe i direct current generator armature voltage; By the direct current generator principle, the driving force on the driving wheel is:

$f_i=\frac{1}{\mathrm{rg}}\·k_m{I}_i$

The linear velocity of driving wheel can be derived as follows:

∵

∴

(C) governing equation of electric wheelchair

Can get by step 1 (A) with (B),

$\left\{\begin{array}{c}{f}_1+f_2=\frac{k_m}{\mathrm{rg}{R}_a}(u_1+u_2)-2\frac{k_m{k}_e}{r^2{g}^2{R}_a}v\\ f_1-f_2=\frac{k_m}{\mathrm{rg}{R}_a}(u_1-u_2)-2\frac{{\mathrm{lk}}_m{k}_e}{r^2{g}^2{R}_a}\mathrm{\ω}\end{array}\right.$

$\left\{\begin{array}{c}M\stackrel{\·}{v}+2\frac{k_m{k}_e}{r^2{g}^2{R}_a}v=\frac{k_m}{\mathrm{rg}{R}_a}(u_1+u_2)\\ J\stackrel{\·}{\mathrm{\ω}}+2\frac{l^2{k}_m{k}_e}{r^2{g}^2{R}_a}\mathrm{\ω}=\frac{{\mathrm{lk}}_m}{\mathrm{rg}{R}_a}(u_1-u_2)\end{array}\right.$

That is,

$\left\{\begin{array}{c}\frac{r^2{g}^2{R}_{a}M}{2k_e{k}_m}\stackrel{\·}{v}+v=\frac{\mathrm{rg}}{2k_e}(u_1+u_2)\\ \frac{r^2{g}^2{R}_{a}J}{2l^2{k}_e{k}_m}\stackrel{\·}{\mathrm{\ω}}+\mathrm{\ω}=\frac{\mathrm{rg}}{2l{k}_e}(u_1-u_2)\end{array}\right.$

$T\left[\begin{array}{c}\stackrel{\·}{v}\\ \stackrel{\·}{\mathrm{\ω}}\end{array}\right]+\left[\begin{array}{c}v\\ \mathrm{\ω}\end{array}\right]=K\left[\begin{array}{c}{\stackrel{\→}{u}}_1\\ {\stackrel{\→}{u}}_2\end{array}\right]$

Wherein, Be left and right sides armature voltage sum,

Poor for left and right sides armature voltage, T is a governing equation output vector coefficient, T ₁, T ₂Be the component of T, K is a governing equation input vector coefficient, K ₁, K ₂Component for K.

${\stackrel{\→}{u}}_1=u_1+u_2$

${\stackrel{\→}{u}}_2=u_1-u_2$

$T=\left[\begin{array}{cc}{T}_1& 0\\ 0& T_2\end{array}\right]=\frac{r^2{g}^2{R}_a}{2k_e{k}_m}\left[\begin{array}{cc}M& 0\\ 0& J/l^2\end{array}\right]$

$K=\left[\begin{array}{cc}{K}_1& 0\\ 0& K_2\end{array}\right]=\frac{\mathrm{rg}}{2k_e}\left[\begin{array}{cc}1& 0\\ 0& 1/l\end{array}\right]$

By above-mentioned derivation as can be known, can pass through

Control electric wheelchair linear velocity v,

Control electric wheelchair angular velocity omega;

(D) mensuration of governing equation parameter

By the parameter of motor and electric wheelchair as can be known:

$K_1=\frac{v_1}{u_1}$

$K_2=\frac{K_1}{l}$

$T_1=\frac{r^2{g}^2{R}_a}{2k_e{k}_m}\·M=2\left(\frac{\mathrm{rg}}{2k_e}\right)\left(\frac{\mathrm{rg}}{2k_m}\right)R_{a}M=2{\left(K_1\right)}^2{R}_{a}M$

$T_2=\frac{r^2{g}^2{R}_a}{2k_e{k}_m}\·\frac{J}{l^2}=2{\left(K_1\right)}^2{R}_a\frac{J}{l^2}.$

The controller design method of electric wheelchair of the present invention has reduced the computational burden of node in the wireless sensor network, and economical and effective also satisfies the requirement of wireless sensor network to electric wheelchair.

Description of drawings

The control system circuit block diagram of Fig. 1 electric wheelchair of the present invention.

Fig. 2 electric wheelchair kinetic model of the present invention.

The direct current generator armature circuit of Fig. 3 electric wheelchair of the present invention.

Electric wheelchair under Fig. 4 wireless sensor network of the present invention.

Embodiment

Below in conjunction with accompanying drawing content of the present invention is described in further detail.

The electric wheelchair controller that a kind of Zigbee inserts, described controller comprises master control board, data acquisition board 9, motor control box 12 and wireless communication module 2; Wireless communication module 2 is connected with master control board and communicates by letter, and data acquisition board 9 is connected with master control board, and motor control box 12 is connected with master control board; In master control board, also be connected with left infrared switch 1, right infrared switch 3, first ultrasonic sensor 4, second ultrasonic sensor 5, the 3rd ultrasonic sensor 7, the 4th ultrasonic sensor 8 and electronic compass 11; Also be connected with revolver direct current generator 14 and right wheel direct current generator 15 at motor control box 12; Revolver direct current generator 14 is connected with data acquisition board 9 by left code-disc 13, and right wheel direct current generator 15 is connected with data acquisition board 9 by right code-disc 16; The electric wheelchair kinematic parameter that left side infrared switch 1, right infrared switch 3, first ultrasonic sensor 4, second ultrasonic sensor 5, the 3rd ultrasonic sensor 7, the 4th ultrasonic sensor 8, electronic compass 11 and data acquisition board 9 collect is input to master control board, and the rotating speed of revolver direct current generator 14 and right wheel direct current generator 15 is adjusted in master control board by output order; On data acquisition board 9, be connected with gyroscope, the angular speed that the gyroscope survey electric wheelchair rotates.Described master control board is made of I2C interface, a RS232 interface 18, the 2nd RS232 interface 22, an IO mouth 17, the 2nd IO mouth 19 and the spi bus 20 of CPU and setting around CPU.

(1) acquisition parameter: left infrared switch 1 and right infrared switch 3 detect the barrier around the electric wheelchair; First ultrasonic sensor 4, second ultrasonic sensor 5, the 3rd ultrasonic sensor 7 and the 4th ultrasonic sensor 8 are measured the distance of electric wheelchair and barrier on every side; Electronic compass 11 measure electric wheelchairs definitely towards; Data acquisition board 9 is gathered the rotating speed of revolver direct current generator 14 and right wheel direct current generator 15;

(2) set up controlling models: the kinetic model of setting up the differential driving electric wheelchair of two-wheeled earlier, set up the direct current generator mathematical model again, at last in conjunction with the controlling models of kinetic model with the direct current generator mathematical model acquisition electric wheelchair of the differential driving electric wheelchair of two-wheeled;

(3) set up radio communication: wireless communication module 2 is connected with master control board, master control board inserts radio sensing network by wireless communication module 2, wireless communication module 2 is transmitted to master control board with the semanteme instruction that radio sensing network sends, master control board is resolved semantic instruction and is driven revolver direct current generator 14 and rotates with right wheel direct current generator 15, thus the motion of control electric wheelchair;

(4) carry out steering order: the parameter of gathering in the step (1) is input to the kinematic parameter that obtains electric wheelchair in the controlling models that obtains in the step (2); Step (3) passes to radio sensing network with the kinematic parameter of electric wheelchair, the motion of the semantic instruction control electric wheelchair that radio sensing network sends.

The concrete processing mode of step 1:

(A) adding of sensor

The electric wheelchair of the differential driving of two-wheeled is carried out the semanteme instruction that wireless sensor network sends and is kept away barrier and need obtain information such as the distance of barrier in self motion state and the environment and shape.Use the perception that expands electric wheelchair as lower sensor: adopt code-disc to measure the rotating speed of electric wheelchair driving wheel, and then can calculate the linear velocity and the angular velocity of electric wheelchair; Adopt ultrasonic sensor to measure the distance of electric wheelchair and peripheral obstacle; Adopt infrared switch fast detecting electric wheelchair emergent barrier on every side; The angular speed that adopts the gyroscope survey electric wheelchair to rotate; Adopt electronic compass 11 measure electric wheelchairs definitely towards.

Code-disc and the coaxial installation of the direct current generator of electric wheelchair driving wheel, the coded disc counting that record this moment need be converted into the rotating speed of driving wheel through the gear ratio of wheel box.Ultrasonic sensor is installed in the side of electric wheelchair, can obtain the electric wheelchair side from the distance of metope and can extrapolate the sudden change of metope in view of the above, and these data can be used for electric wheelchair and independently walk along wall.Infrared switch is installed in the front and back of electric wheelchair, detects emergent barrier in the electric wheelchair motion process.As electric wheelchair angular rate measurement backup device, gyroscope can play a role under electric wheelchair skids the situation that causes code-disc to lose efficacy.Electronic compass 11 can measure electric wheelchair definitely towards, prevent angular error accumulation.

(B) adding of wireless communication module 2

Electric wheelchair uses wireless communication module 2 to insert wireless sensor network, and wireless communication module 2 adopts CC2420 as the radio-frequency receiving-transmitting device, to realize the support to the Zigbee agreement.Wireless communication module 2 receives the semanteme instruction that network sends, and it is transmitted to the control system of electric wheelchair.Control system is resolved the semanteme instruction, carries out under the assistance of sensor.

To be described in detail the concrete processing mode of step 2 below:

(A) governor circuit is realized

Main control board links to each other with wireless communication module 2 by a RS232 interface 18, and this module and network communication of wireless sensor and the semanteme instruction that will receive are transmitted to main control board.Main control board receives the semantic command information that transmits, and concentrates and handle the data that ultrasonic sensor, electronic compass 11, infrared switch and sensor data acquisition plate 9 obtain, the motion of control electric wheelchair.Master control circuit board comprises following several sections: the CPU of main control chip circuit adopts Atmega128 to meet the demands; The ultrasonic sensor interface circuit uses the I2C interface; Electronic compass 11 interface circuits use the 2nd RS232 interface 22; Wireless communication module 2 interface circuits use a RS232 interface 18; The infrared switch interface circuit according to the number of infrared switch, takies the different IO mouth of main control chip; The data acquisition interface circuit uses spi bus 20.

(B) data acquisition circuit is realized

Data acquisition circuit can be alleviated the burden of main control circuit.The pulse signal of 9 pairs of code-discs of data acquisition board is counted simultaneously gyrostatic analog output signal is quantized, and at last the data that collect is sent to total control circuit by spi bus.

Referring to Fig. 1.

To be described in detail the concrete processing mode of step 3 below:

(A) kinetic model of the differential driving electric wheelchair of two-wheeled

The differential driving of two-wheeled is a kind of type of drive that present electric wheelchair uses the most generally.Two trailing wheels of the differential driving electric wheelchair of two-wheeled are driving wheel, and each drives with a direct current generator.Two other front-wheel is an engaged wheel, supports electric wheelchair and follows rear wheel movement.Referring to Fig. 2, it is the dynamics synoptic diagram of the differential driving electric wheelchair of two-wheeled, and M is the gross mass of electric wheelchair, and J is the total moment of inertia of electric wheelchair, and r is the driving wheel radius, and l is half of driving wheel spacing, f ₁, f ₂Be the driving force of left and right sidesing driving wheel, v ₁, v ₂Be the linear velocity of left and right sidesing driving wheel, F is the synthetic thrust of electric wheelchair, and τ is the torque of electric wheelchair, and v is the aggregate velocity of electric wheelchair, and ω is the accumulated angle speed of electric wheelchair.According to dynamics formula, following relationship is set up:

$\left\{\begin{array}{c}F=f_1+f_2\\ \mathrm{\τ}=l(f_1-f_2)\end{array}\right.$

$\left\{\begin{array}{c}{v}_1=v+\mathrm{l\ω}\\ v_2=v-\mathrm{l\ω}\end{array}\right.$

$\left\{\begin{array}{c}M\stackrel{\·}{v}=F=f_1+f_2\\ J\stackrel{\·}{\mathrm{\ω}}=\mathrm{\τ}=l(f_1-f_2)\end{array}\right.$

(B) direct current generator mathematical model

The trailing wheel of electric wheelchair is driven by direct current generator.The circuit of direct current generator is referring to shown in Figure 3.Wherein, reducer casing deceleration g＜1,

Be i dc motor speed, k _mBe the dynamo-electric constant of direct current generator, k _eBe direct current generator electromagnetic constant, E _AiBe i direct current generator electromotive force, R _aBe direct current generator armature resistance, I _iBe i direct current generator armature supply, u _iBe i direct current generator armature voltage, Expression is carried out differentiate to v.By the direct current generator principle, the driving force on the driving wheel is:

$f_i=\frac{1}{\mathrm{rg}}\·k_m{I}_i$

The linear velocity of driving wheel can be derived as follows:

∵

∴

(C) governing equation of electric wheelchair

Can get by step 1 (A) with (B),

$\left\{\begin{array}{c}{f}_1+f_2=\frac{k_m}{\mathrm{rg}{R}_a}(u_1+u_2)-2\frac{k_m{k}_e}{r^2{g}^2{R}_a}v\\ f_1-f_2=\frac{k_m}{\mathrm{rg}{R}_a}(u_1-u_2)-2\frac{{\mathrm{lk}}_m{k}_e}{r^2{g}^2{R}_a}\mathrm{\ω}\end{array}\right.$

$\left\{\begin{array}{c}M\stackrel{\·}{v}+2\frac{k_m{k}_e}{r^2{g}^2{R}_a}v=\frac{k_m}{\mathrm{rg}{R}_a}(u_1+u_2)\\ J\stackrel{\·}{\mathrm{\ω}}+2\frac{l^2{k}_m{k}_e}{r^2{g}^2{R}_a}\mathrm{\ω}=\frac{{\mathrm{lk}}_m}{\mathrm{rg}{R}_a}(u_1-u_2)\end{array}\right.$

That is,

$\left\{\begin{array}{c}\frac{r^2{g}^2{R}_{a}M}{2k_e{k}_m}\stackrel{\·}{v}+v=\frac{\mathrm{rg}}{2k_e}(u_1+u_2)\\ \frac{r^2{g}^2{R}_{a}J}{2l^2{k}_e{k}_m}\stackrel{\·}{\mathrm{\ω}}+\mathrm{\ω}=\frac{\mathrm{rg}}{2l{k}_e}(u_1-u_2)\end{array}\right.$

$T\left[\begin{array}{c}\stackrel{\·}{v}\\ \stackrel{\·}{\mathrm{\ω}}\end{array}\right]+\left[\begin{array}{c}v\\ \mathrm{\ω}\end{array}\right]=K\left[\begin{array}{c}{\stackrel{\→}{u}}_1\\ {\stackrel{\→}{u}}_2\end{array}\right]$

Wherein,

${\stackrel{\→}{u}}_1=u_1+u_2$

${\stackrel{\→}{u}}_2=u_1-u_2$

$T=\left[\begin{array}{cc}{T}_1& 0\\ 0& T_2\end{array}\right]=\frac{r^2{g}^2{R}_a}{2k_e{k}_m}\left[\begin{array}{cc}M& 0\\ 0& J/l^2\end{array}\right]$

$K=\left[\begin{array}{cc}{K}_1& 0\\ 0& K_2\end{array}\right]=\frac{\mathrm{rg}}{2k_e}\left[\begin{array}{cc}1& 0\\ 0& 1/l\end{array}\right]$

By above-mentioned derivation as can be known, can pass through

Control electric wheelchair linear velocity v,

Control electric wheelchair angular velocity omega.

(D) mensuration of governing equation parameter

By the parameter of motor and electric wheelchair as can be known:

$K_1=\frac{v_1}{u_1}$

$K_2=\frac{K_1}{l}$

$T_1=\frac{r^2{g}^2{R}_a}{2k_e{k}_m}\·M=2\left(\frac{\mathrm{rg}}{2k_e}\right)\left(\frac{\mathrm{rg}}{2k_m}\right)R_{a}M=2{\left(K_1\right)}^2{R}_{a}M$

$T_2=\frac{r^2{g}^2{R}_a}{2k_e{k}_m}\·\frac{J}{l^2}=2{\left(K_1\right)}^2{R}_a\frac{J}{l^2}$

To be described in detail the concrete processing mode of step 4 below:

(A) Zigbee inserts

Referring to Fig. 4, electric wheelchair uses the CC2420 radio-frequency (RF) transceiver of wireless communication module 2 to insert wireless sensor network with Zigbee.Wireless sensor network uses the Zigbee protocol communication, and each node in the network all is assigned with one 16 MAC Address.As a node in the wireless sensor network, electric wheelchair has a unique physical address in network.The figure place of physical address has limited the number of the electric wheelchair that moves in the network less than 65536.

(B) execution of semantic instruction

The instruction of semanteme that wireless sensor network sends mainly contains and takes the air line, moves in curves, walk and stop 4 kinds along wall.The control system of electric wheelchair is resolved the semanteme instruction, drives direct current generator and rotates, the motion of control electric wheelchair.The controlling models based on electric wheelchair is carried out in the parsing of semantic instruction.

Taking the air line is a kind of basic act of electric wheelchair motion control, simultaneously it also be the control electric wheelchair move in curves, along basis that wall is walked etc.The realization that takes the air line mainly relies on the control to the electric wheelchair corner.Can record the real-time rotating speed of direct current generator with code-disc, realize control corner with the mode of FEEDBACK CONTROL.Two wheels turned over distance and equate when the differential driving electric wheelchair of two-wheeled took the air line, and it is 0 can make it along straight line moving that the control electric wheelchair makes corner in its motion process.The linear velocity of given electric wheelchair is v, adopts PD control to make its rotational angle theta to angle _d=0.

Move in curves and on the basis that takes the air line, to develop.Add correction coefficient for electric wheelchair motor on one side, the control electric wheelchair takes the air line electric wheelchair is walked along camber line.The camber line angle can realize by the distance that the control wheel is passed by.

On larger distance, making the electric wheelchair run trace is that one section accurate straight line is very difficult.If can utilize environmental information around the electric wheelchair (as the wall of electric wheelchair both sides, barrier etc.), both can carry out suitable hiding to barrier, can proofread and correct the motion of electric wheelchair again.In structurized environment (as the building etc.), when the electric wheelchair both sides are wall, plank etc., allow electric wheelchair keep the certain spacing walking along wall, plank etc., can proofread and correct its motion effectively.Electric wheelchair also has site error when wall moves with existing angular error between metope, can be with these two error weighting, unifiedly be converted to angle, and control electric wheelchair then and take the air line, can realize that electric wheelchair walks along wall.When the linear velocity of electric wheelchair and angular velocity were made as zero simultaneously, electric wheelchair stopped.

Above content is to further describing that the present invention did in conjunction with concrete preferred implementation; can not assert that the specific embodiment of the present invention only limits to this; for the general technical staff of the technical field of the invention; without departing from the inventive concept of the premise; can also make some simple deduction or replace, all should be considered as belonging to the present invention and determine scope of patent protection by claims of being submitted to.

Claims (4)

1, a kind of electric wheelchair controller of Zigbee access, it is characterized in that: described controller comprises master control board, data acquisition board (9), motor control box (12) and wireless communication module (2); Wireless communication module (2) is connected with master control board and communicates by letter, and data acquisition board (9) is connected with master control board, and motor control box (12) is connected with master control board; In master control board, also be connected with left infrared switch (1), right infrared switch (3), first ultrasonic sensor (4), second ultrasonic sensor (5), the 3rd ultrasonic sensor (7), the 4th ultrasonic sensor (8) and electronic compass (11); Also be connected with revolver direct current generator (14) and right wheel direct current generator (15) at motor control box (12); Revolver direct current generator (14) is connected with data acquisition board (9) by left code-disc 13, and right wheel direct current generator (15) is connected with data acquisition board (9) by right code-disc (16); The electric wheelchair kinematic parameter that left side infrared switch (1), right infrared switch (3), first ultrasonic sensor (4), second ultrasonic sensor (5), the 3rd ultrasonic sensor (7), the 4th ultrasonic sensor (8), electronic compass (11) and data acquisition board (9) collect is input to master control board, and the rotating speed of revolver direct current generator (14) and right wheel direct current generator (15) is adjusted in master control board by output order; On data acquisition board (9), be connected with gyroscope, the angular speed that the gyroscope survey electric wheelchair rotates.

2, the electric wheelchair controller that inserts according to the described a kind of Zigbee of claim 1, it is characterized in that: described master control board is made of CPU and the I2C interface that is provided with around CPU, a RS232 interface (18), the 2nd RS232 interface (22), an IO mouth (17), the 2nd IO mouth (19) and spi bus (20).

3, the control method of the electric wheelchair controller that inserts according to the described a kind of Zigbee of claim 1 is characterized in that:

(1) acquisition parameter: left infrared switch (1) and right infrared switch (3) detect the barrier around the electric wheelchair; First ultrasonic sensor (4), second ultrasonic sensor (5), the 3rd ultrasonic sensor (7) and the 4th ultrasonic sensor (8) are measured the distance of electric wheelchair and barrier on every side; Electronic compass (11) measure electric wheelchair definitely towards; Data acquisition board (9) is gathered the rotating speed of revolver direct current generator (14) and right wheel direct current generator (15);

(2) set up controlling models: the kinetic model of setting up the differential driving electric wheelchair of two-wheeled earlier, set up the direct current generator mathematical model again, at last in conjunction with the controlling models of kinetic model with the direct current generator mathematical model acquisition electric wheelchair of the differential driving electric wheelchair of two-wheeled;

(3) set up radio communication: wireless communication module (2) is connected with master control board, master control board inserts radio sensing network by wireless communication module (2), wireless communication module (2) is transmitted to master control board with the semanteme instruction that radio sensing network sends, master control board is resolved semantic instruction and driving revolver direct current generator (14) and right wheel direct current generator (15) and is rotated, thus the motion of control electric wheelchair;

(4) carry out steering order: the parameter of gathering in the step (1) is input to the kinematic parameter that obtains electric wheelchair in the controlling models that obtains in the step (2); Step (3) passes to radio sensing network with the kinematic parameter of electric wheelchair, the motion of the semantic instruction control electric wheelchair that radio sensing network sends.

4, the control method of the electric wheelchair controller that inserts according to the described a kind of Zigbee of claim 3 is characterized in that: described step (2) is according to following steps:

(1) kinetic model of the differential driving electric wheelchair of two-wheeled

Two trailing wheels of the differential driving electric wheelchair of two-wheeled are driving wheel, and each drives with a direct current generator; Two other front-wheel is an engaged wheel, supports electric wheelchair and follows rear wheel movement; M is the gross mass of electric wheelchair, and J is the total moment of inertia of electric wheelchair, and r is the driving wheel radius, and l is half of driving wheel spacing, f ₁, f ₂Be the driving force of left and right sidesing driving wheel, v ₁, v ₂Be the linear velocity of left and right sidesing driving wheel, F is the synthetic thrust of electric wheelchair, and τ is the torque of electric wheelchair, and v is the aggregate velocity of electric wheelchair, and ω is the accumulated angle speed of electric wheelchair.According to dynamics formula, following relationship is set up:

$\left\{\begin{array}{c}F=f_1+f_2\\ \mathrm{\τ}=l(f_1-f_2)\end{array}\right.$

$\left\{\begin{array}{c}{v}_1=v+\mathrm{l\ω}\\ v_2=v-\mathrm{l\ω}\end{array}\right.$

$\left\{\begin{array}{c}M\stackrel{\·}{v}=F=f_1+f_2\\ J\stackrel{\·}{\mathrm{\ω}}=\mathrm{\τ}=l(f_1-f_2)\end{array}\right.$

(2) direct current generator mathematical model

The trailing wheel of electric wheelchair is driven by direct current generator; Wherein, reducer casing deceleration g＜1,

Be i dc motor speed, k _mBe the dynamo-electric constant of direct current generator, k _eBe direct current generator electromagnetic constant, E _AiBe i direct current generator electromotive force, R _aBe direct current generator armature resistance, I _iBe i direct current generator armature supply, u _iBe i direct current generator armature voltage,

Expression is carried out differentiate to v; By the direct current generator principle, the driving force on the driving wheel is:

$f_i=\frac{1}{\mathrm{rg}}\·k_m{I}_i$

The linear velocity of driving wheel can be derived as follows:

(3) governing equation of electric wheelchair

Can get by step 1 (A) with (B),

$\left\{\begin{array}{c}{f}_1+f_2=\frac{k_m}{\mathrm{rg}{R}_a}(u_1+u_2)-2\frac{k_m{k}_e}{r^2{g}^2{R}_a}v\\ f_1-f_2=\frac{k_m}{\mathrm{rg}{R}_a}(u_1-u_2)-2\frac{{\mathrm{lk}}_m{k}_e}{r^2{g}^2{R}_a}\mathrm{\ω}\end{array}\right.$

$\left\{\begin{array}{c}M\stackrel{\·}{v}+2\frac{k_m{k}_e}{r^2{g}^2{R}_a}v=\frac{k_m}{\mathrm{rg}{R}_a}(u_1+u_2)\\ J\stackrel{\·}{\mathrm{\ω}}+2\frac{l^2{k}_m{k}_e}{r^2{g}^2{R}_a}\mathrm{\ω}=\frac{{\mathrm{lk}}_m}{\mathrm{rg}{R}_a}(u_1-u_2)\end{array}\right.$

That is,

$\left\{\begin{array}{c}\frac{r^2{g}^2{R}_{a}M}{{2k}_e{k}_m}\stackrel{\·}{v}+v=\frac{\mathrm{rg}}{2k_e}(u_1+u_2)\\ \frac{r^2{g}^2{R}_{a}J}{{2l}^2{k}_e{k}_m}\stackrel{\·}{\mathrm{\ω}}+\mathrm{\ω}=\frac{\mathrm{rg}}{2l{k}_e}(u_1-u_2)\end{array}\right.$

$T\left[\begin{array}{c}\stackrel{\·}{v}\\ \stackrel{\·}{\mathrm{\ω}}\end{array}\right]+\left[\begin{array}{c}v\\ \mathrm{\ω}\end{array}\right]=K\left[\begin{array}{c}{\stackrel{\→}{u}}_1\\ {\stackrel{\→}{u}}_2\end{array}\right]$

Wherein,

${\stackrel{\→}{u}}_1=u_1+u_2$

${\stackrel{\→}{u}}_2=u_1-u_2$

$T=\left[\begin{array}{cc}{T}_1& 0\\ 0& T_2\end{array}\right]=\frac{r^2{g}^2{R}_a}{{2k}_e{k}_m}\left[\begin{array}{cc}M& 0\\ 0& J/l^2\end{array}\right]$

$K=\left[\begin{array}{cc}{K}_1& 0\\ 0& K_2\end{array}\right]=\frac{\mathrm{rg}}{{2k}_e}\left[\begin{array}{cc}1& 0\\ 0& 1/l\end{array}\right]$

By above-mentioned derivation as can be known, can pass through

Control electric wheelchair linear velocity v,

Control electric wheelchair angular velocity omega;

(4) mensuration of governing equation parameter

By the parameter of motor and electric wheelchair as can be known:

$K_1=\frac{v_1}{u_1}$

$K_2=\frac{K_1}{l}$

$T_1=\frac{r^2{g}^2{R}_a}{{2k}_e{k}_m}\·M=2\left(\frac{\mathrm{rg}}{{2k}_e}\right)\left(\frac{\mathrm{rg}}{2k_m}\right)R_{a}M=2{\left(K_1\right)}^2{R}_{a}M$

$T_2=\frac{r^2{g}^2{R}_a}{{2k}_e{k}_m}\·\frac{J}{l^2}=2{\left(K_1\right)}^2{R}_a\frac{J}{l^2}$

Wherein,

Be left and right sides armature voltage sum,

Poor for left and right sides armature voltage, T is a governing equation output vector coefficient, T ₁, T ₂Be the component of T, K is a governing equation input vector coefficient, K ₁, K ₂Component for K.

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