CN101655697A - Constant-level separating device for model rocket - Google Patents

Abstract

The invention provides a constant-level separating device for a model rocket, which comprises a data processor (U1), a data acquisition unit (U2) and a steering engine (U3), wherein the data processor(U1) is connected with the steering engine (U3) and the data acquisition unit (U2); the data acquisition unit (U2) is digital signal output through the four-wire transmission mode of the SPI digitaltransmission protocol; and the control of the steering engine (U3) is completed by outputting analog PWM signals by the I/O port of the data processor (U1). The invention has the characteristics of high acquisition precision, good reliability, simple structure and the like by acquiring the acceleration value of the model rocket in the rising process and carrying out quadric integrals calculation.The system hardware adopts the smallest MMA755 acceleration transducer in the world at present, the steering engine, the weight of which is only 9g, and ultralight lithium batteries, thus the constant-level separating system has the advantages of small volume, light weight, convenient installation and the like under the condition of meeting the design requirements, and the constant-level separating device also has simple system structure and low manufacturing cost.

Description

Constant-level separating device for model rocket

(1) technical field

What the present invention relates to is a kind of model rocket control device, specifically a kind of model rocket tripping device.

(2) background technology

The specified altitude assignment separation of model rocket often appears in the domestic and international various model plane contest as a match, and the match request model rocket can separate return capsule on specified altitude assignment.According to formula ma=F-G=F-mg as can be known $a=\frac{F}{m}-g,$ Engine spray finishes the back model rocket can be similar to the upthrow motion of regarding certain initial velocity as.Displacement during separation by formula is as can be known $S=\mathrm{vt}-\frac{{\mathrm{<figure-callout\; id="2"\; label="gt"\; filenames="A2009100728360008H1.png"\; state="\{\{state\}\}">gt</figure-callout>}}^2}{2}$ So the separation method disengaging time that sprays owing to the time-delay retroaction of adopting engine based on this traditional disjunctive model rocket is a definite value, be limited as two kinds so change the method for transport disengaging height, be respectively the weight or the engine model that change rocket model, the method that changes weight is to increase counterweight or excision lightening hole in model rocket, this mode can reduce the efficient or the security of model rocket, change engine model and can accomplish to change initial ignition thrust or disengaging time, but the limited precise height of can't accomplishing of engine model is separated.The instantaneous momentum of separation method detachment process that relies on the engine retroaction to spray simultaneously is bigger to have reduced the separation security.How the enforcement of precise and safety is separated into one of problem demanding prompt solution.In core periodical and patent inquiry, all do not find to invent therewith similar equipment introduction at present.

(3) summary of the invention

The object of the present invention is to provide a kind of precision height, good reliability, constant-level separating device for model rocket simple in structure.

The object of the present invention is achieved like this:

Its composition comprises data processor U1, data acquisition unit U2, steering wheel U3, data processor U1 links to each other with steering wheel U3, data acquisition unit U2, data acquisition unit U2 is digital signal output, by 4 line system transmission modes of SPI digital transmission protocol, the control of steering wheel U3 is to finish by the I/O mouth output simulation pwm signal of data processor U1.

Described data processor U1 adopts Freescale MC9S08AW60 single-chip microcomputer, and data acquisition unit U2 adopts the MMA7455 acceleration sensor chip.

The VDD of digital microprocessor U1 is a power end, and VSS is earth terminal the 4th capacitor C 4 in parallel therebetween, the 5th capacitor C 5; EXTAL1, XTAL are the external oscillator pin, connect crystal oscillator, simultaneously first capacitor C 1 in parallel, second capacitor C, 2 electric capacity; RESET connects the reset signal input end of CPU; SS is that SPI data transmission sheet bit selecting links to each other with the CS of data acquisition unit U2; PTE5/MISO is that the master of SPI data transmission reads from writing the position, and its SDI with acceleration transducer U2 links to each other; PTE6/MOS1 is that the master of SPI data transmission writes from read bit, and its SDO with acceleration transducer U2 is connected; PTE7/SPSCK is connected with the SPC of data acquisition unit U2, is the clock bit of acceleration transducer; The equal ground connection of 2,3,4,5,6,10,11 pin of acceleration transducer U2; 1 pin of acceleration transducer U2 meets VDD-IO, 2 pin of acceleration transducer U2 connect VDD and respectively with the 6th capacitor C 6, the 7th capacitor C 7 ground connection in parallel; Three terminals of the interface of steering wheel U3 connect last port ground connection of PTA0, power vd D of digital microprocessor U1 respectively.

The present invention be directed to model rocket decides high score be difficult to a difficult problem that the model rocket height value is precisely judged, a kind of constant-level separating device for model rocket of development in match.Form by Freescale MC9S08AW60 single-chip microcomputer, integrated 3 axle acceleration MMA7455 modules and steering wheel etc.Carry out communicating by letter between single-chip microcomputer and the MMA7455 via the SPI host-host protocol.I/O mouth output simulation pwm signal control steering wheel rotation by control MC9S08AW60 single-chip microcomputer after the model rocket of surveying through computing reaches specified altitude assignment is revolved cam fixing on the steering wheel axle to turn 90 degrees baffle plate between rocket body and the pod ejected and is implemented to separate.

The present invention has some characteristics like this:

1, is and introduces by Freescale MC9S08AW60 single-chip microcomputer and integrated 3 axle acceleration sensor MMA7455 modules among the model rocket.

2, the height value of model rocket is by getting through quadratic integral for acceleration transducer collection value.

The present invention by the accekeration of model rocket uphill process is gathered and carry out quadratic integral calculate to gather have the precision height, good reliability, characteristics such as simple in structure.System hardware is selected for use steering wheel that at present minimum in the world MMA755 acceleration transducer and quality only have 9g and ultralight lithium battery to make to satisfy under the prerequisite of design requirement, should decide high score have little, the in light weight advantage such as installation of being convenient to of volume from system, simultaneity factor is simple in structure cheap.

(4) description of drawings

The composition diagram of Fig. 1 constant-level separating device for model rocket;

The schematic diagram of Fig. 2 constant-level separating device for model rocket;

Fig. 3 constant-level separating device for model rocket circuit theory diagrams;

Fig. 4 constant-level separating device for model rocket program flow diagram;

Fig. 5 model rocket height value integration is asked the method synoptic diagram.

(5) embodiment

For example the present invention is done description in more detail below in conjunction with accompanying drawing:

In conjunction with Fig. 1, invention comprises data processor U1, data acquisition unit U2, steering wheel U3, and wherein U1 adopts Freescale MC9S08AW60 single-chip microcomputer, and U2 adopts the MMA7455 chip.

In conjunction with Fig. 2, single-chip microcomputer U1 links to each other with steering wheel U3, acceleration transducer U2, and U2 is digital signal output, by 4 line system transmission modes of SPI digital transmission protocol.U3 is that the control single chip computer I/O mouth output simulation pwm signal that passes through is finished.

In conjunction with Fig. 3, the VDD of digital microprocessor U1 (17 pin) is a power end, and VSS (16 pin) is earth terminal shunt capacitance C4, C5 therebetween.EXTAL1 (38 pin), XTAL (37 pin) are the external oscillator pin, connect crystal oscillator, simultaneously C1 in parallel, C2 electric capacity.RESET (3 pin) connects the reset signal input end of CPU.SS (12 pin) is the CS (7 pin) of SPI data transmission sheet bit selecting and U2.PTE5/MISO (13 pin) reads from writing the position for the master of SPI data transmission, and effect is to allow single-chip microcomputer by SPI communication protocol acceleration transducer to be carried out information initializing, and it links to each other with the SDI (12 pin) of acceleration transducer U2.PTE6/MOS1 (14 pin) is for the master of SPI data transmission writes from read bit, and effect is that the data of degree of will speed up sensor acquisition are passed to by the SPI Data Transport Protocol and analyze computing in the single-chip microcomputer, and it is connected with the SDO (12 pin) of acceleration transducer U2.PTE7/SPSCK (15 pin) is connected with the SPC (14 pin) of U2, is the clock bit of acceleration transducer.The equal ground connection of 2,3,4,5,6,10,11 pin of acceleration transducer U2.1 pin meets VDD-IO, 2 pin connect VDD and respectively with capacitor C 6, C7 ground connection in parallel.U3 is the steering wheel interface, and three terminals connect PTA0 (21 pin), last port ground connection of power vd D of U1 respectively.

The principle of work of take the altitude piece-rate system is to measure Z axle acceleration value by acceleration transducer.By the SPI data transfer mode acceleration transducer is carried out initialization and select after suitable range and the transmission form image data to reach single-chip microcomputer to carry out computing, the cam of fixing on the steering wheel axle is revolved turn 90 degrees through quadratic integral computing PWM control steering wheel rotation by the simulation of PA0 end when the gained model rocket reaches specified altitude assignment after baffle plate between rocket body and the pod is ejected enforcement to separate.Whereby from reaching purpose of design.System accuracy depend on the MMA7455 acceleration transducer setting range (2G, 4G, 8G), read figure place (8,10) and sampling time interval.

In conjunction with Fig. 4, this model rocket tripping device program is divided into 6 steps.Step (1): earlier acceleration transducer is carried out initialization, the sensor that this device adopted has three ranges (2G, 4G, 8G), two kinds of degree of accuracy (8,10), two kinds of communication line patterns (4 line systems, 3 line systems).So need acceleration transducer is carried out initialization, adopt which kind of pattern with decision.Step (2): configuration timer, the purpose of this step are to set the sampling time of single-chip microcomputer, and its preseting length goes to depend on and needs precision and single-chip microcomputer arithmetic speed.Step (3): open timer, master routine brings into operation.Step (4): import data, in the numerical value importing single-chip microcomputer by SPI Data Transport Protocol degree of will speed up sensor acquisition.Step (5): the height computing, carry out computing for the data that single-chip microcomputer is received, try to achieve height value.If reaching specified altitude assignment then enters step (6), does not enter step (7) if reach.Step (6): the control steering wheel, owing to reached specified altitude assignment, separate so rotate enforcement by the Single-chip Controlling steering wheel.Step (7): judge whether timer overflows.If do not overflow, then program is in waiting status, and till overflowing, timer overflows then, and program goes to step (5) and continues for the height value computing, and is final after reaching specified altitude assignment, enters step (6).

In conjunction with Fig. 5, with the measured just discrete accekeration of physical quantity of acceleration transducer, expect distance value, must carry out integration twice to accekeration.The native system program adopts imfinitesimal method to carry out integral operation, and step was divided into for two steps:

The first step: velocity amplitude calculates.F (i) is from t as figure shows _mThe time be carved into t _nEach f (i) value and the adding up of infinitesimal Δ t sum of products constantly can be passed through integral formula afterwards during constant volume component was constantly found the solution and can be converted to $F\left(n\right)-F\left(m\right)=\underset{i=m}{\overset{n}{\mathrm{\&Sigma;}}}f\left(i\right)\mathrm{\&Delta;t},$ Try to achieve the discrete velocity amplitude of model rocket. $V_s\left(n\right)-V_s\left(m\right)=\underset{a=j}{\overset{n}{\mathrm{\&Sigma;}}}{a}_z\left(i\right)\mathrm{\&Delta;t},$ When the emission beginning, the rocket initial velocity is zero, i.e. V _z(j) so=0 as can be known $V_z\left(n\right)=\underset{a=j}{\overset{n}{\mathrm{\&Sigma;}}}{a}_z\left(i\right)\mathrm{\&Delta;t}.$

Second step: height value calculates.Distance value can be tried to achieve by the integration to velocity amplitude, and method is consistent with the first step, and discrete velocity amplitude integration is just obtained climb $S_z=\underset{j=0}{\overset{n}{\mathrm{\&Sigma;}}}{V}_z\left(j\right)\mathrm{\&Delta;t}=\underset{j=0}{\overset{n}{\mathrm{\&Sigma;}}}\left(\underset{i=j}{\overset{n}{\mathrm{\&Sigma;}}}{a}_z\left(i\right)\mathrm{\&Delta;t}\right)\mathrm{\&Delta;t}$ S wherein _zBe Z axial translation amount, a _z(i) be that Z axle acceleration value (gravity acceleration value being considered wherein to pass through sequential operation) the Δ t that detects is the acquisition time interval of adjacent two accekerations.

Claims (3)

1, a kind of constant-level separating device for model rocket, its composition comprises data processor (U1), data acquisition unit (U2), steering wheel (U3), it is characterized in that: data processor (U1) links to each other with steering wheel (U3), data acquisition unit (U2), data acquisition unit (U2) is digital signal output, by 4 line system transmission modes of SPI digital transmission protocol, the control of steering wheel (U3) is to finish by the I/O mouth output simulation pwm signal of data processor (U1).

2, constant-level separating device for model rocket according to claim 1 is characterized in that: described data processor (U1) adopts Freescale MC9S08AW60 single-chip microcomputer, and data acquisition unit (U2) adopts the MMA7455 acceleration sensor chip.

3, constant-level separating device for model rocket according to claim 2 is characterized in that: the VDD of digital microprocessor (U1) is a power end, and VSS is earth terminal the 4th electric capacity (C4) in parallel therebetween, the 5th electric capacity (C5); EXTAL1, XTAL are the external oscillator pin, connect crystal oscillator, simultaneously first electric capacity in parallel (C1), second electric capacity (C2) electric capacity; RESET connects the reset signal input end of CPU; SS is that SPI data transmission sheet bit selecting links to each other with the CS of data acquisition unit (U2); PTE5/MISO is that the master of SPI data transmission reads from writing the position, and its SDI with acceleration transducer (U2) links to each other; PTE6/MOS1 is that the master of SPI data transmission writes from read bit, and its SDO with acceleration transducer (U2) is connected; PTE7/SPSCK is connected with the SPC of data acquisition unit (U2), is the clock bit of acceleration transducer; The equal ground connection of 2,3,4,5,6,10,11 pin of acceleration transducer (U2); 1 pin of acceleration transducer (U2) meets VDD-IO, 2 pin of acceleration transducer (U2) connect VDD and respectively with the 6th electric capacity (C6), the 7th electric capacity (C7) ground connection in parallel; Three terminals of the interface of steering wheel (U3) connect last port ground connection of PTA0, power vd D of digital microprocessor (U1) respectively.

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