Comment calculer la vitesse de course à l'aide de la sonde d'accéléromètre dans android

J'ai essayé de calculer la vitesse de course capteur de TYPE_LINEAR_ACCELEROMETER dans Android, mais les résultats que j'obtiens est très imprécise. Moyen calculé l'accélération est toujours une valeur positive, de sorte qu'il continue d'augmenter. Voici ma procédure et le code, merci de me suggérer quelle est la bonne façon de les calculer à partir de 3 axes accéléromètre de données et où mon code va mal.

Ce que j'ai fait est:

J'obtiens les valeurs de l'accélération dans x, y, z les directions

Résultant de l'accélération a1 = sqrt(x*x + y*y + z*z)

Moyenne de 5 accélération de lectures:

Avg(4) = `(a0 + a1 + a2 + a3 + a4) /5`

Temps delta:

Tdelta = (time of Avg(4)) - (time of Avg(0))

Initialement V(0) est 0 et après que V(0) est calculée précédemment vitesse, d'où:

V(1) = V(0) + at = 0 + Avg(1)
V(2) = V(1) + at = V(1) + Avg(2)
V(n) = V(n-1) + at = V(n-1) + Avg(n)

C'est la façon dont je suis l'obtention de la valeur de la vitesse, mais ce n'est pas la bonne vitesse. Merci de me guider.

C'est le code:

public class TestCalculateVelocityActivity extends Activity implements OnClickListener, SensorEventListener {
final String TAG = getClass().getName().toString();
SensorManager mSensorManager;
Sensor mAccelerometer;
TableLayout accTable;
TextView accl, spd, spd_kmph;
Button btnStart, btnStop, btnClear;
Timer updateTimer;
float []linearAcceleration = new float[3];
Velocity velocity;
Handler handler;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initSensor();
accTable =(TableLayout)findViewById(R.id.country_table);
//accl = (TextView)findViewById(R.id.accl);
spd = (TextView)findViewById(R.id.spd);
spd_kmph = (TextView)findViewById(R.id.spd_kmph);
btnStart = (Button)findViewById(R.id.buttonStart);
btnStart.setOnClickListener(this);
btnStop = (Button)findViewById(R.id.buttonStop);
btnStop.setOnClickListener(this);
btnClear= (Button)findViewById(R.id.buttonClear);
btnClear.setOnClickListener(this);
}
private void initSensor() {
mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION);
if(mAccelerometer == null) {
Toast.makeText(this, "Accelerometer sensor not available", Toast.LENGTH_SHORT).show();
finish();
}
}
void fillTable(float values[]) {
float[] val = values;
TableRow row;
TextView t1, t2, t3;
//Converting to dip unit
int dip = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
(float) 1, getResources().getDisplayMetrics());
//for (int current = 0; current < CountriesList.abbreviations.length; current++) {
row = new TableRow(this);
t1 = new TextView(this);
t1.setTextColor(Color.WHITE);
t1.setBackgroundColor(Color.GRAY);
t2 = new TextView(this);
t2.setTextColor(Color.WHITE);
t2.setBackgroundColor(Color.LTGRAY);
t3 = new TextView(this);
t3.setTextColor(Color.WHITE);
t3.setBackgroundColor(Color.GRAY);
t1.setText(""+val[0]);
t2.setText(""+val[1]);
t3.setText(""+val[2]);
t1.setTypeface(null, 1);
t2.setTypeface(null, 1);
t3.setTypeface(null, 1);
t1.setTextSize(15);
t2.setTextSize(15);
t3.setTextSize(15);
t1.setWidth(150 * dip);
t2.setWidth(150 * dip);
t3.setWidth(150 * dip);
t1.setPadding(20*dip, 0, 0, 0);
row.addView(t1);
row.addView(t2);
row.addView(t3);
accTable.addView(row, new TableLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
}
public void onClick(View v) {
if(v == btnStart) {
mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
velocity = new Velocity();
updateTimer = new Timer("velocityUpdate");
handler = new Handler();
updateTimer.scheduleAtFixedRate(new TimerTask() {
public void run() {
calculateAndUpdate();
}
}, 0, 1200);
}else  if(v == btnStop) {
mSensorManager.unregisterListener(this);
displayVelocityValues();
displayVelocityTable();
velocity = null;
handler = null;
updateTimer.cancel();
} else if(v == btnClear) {
accTable.removeAllViews();
}
}
private void displayVelocityTable() {
try {
accTable.removeAllViews();
double[] vl = velocity.getVlArray();
for(int i = 0; i<vl.length; i++) {
/*Log.d(TAG, "v = " + vl[i] + "mps, "+(vl[i] * 3.6)+ " kmph");*/
//float[] val = values;
TableRow row;
TextView t1, t2;
//Converting to dip unit
int dip = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
(float) 1, getResources().getDisplayMetrics());
//for (int current = 0; current < CountriesList.abbreviations.length; current++) {
row = new TableRow(this);
t1 = new TextView(this);
t1.setTextColor(Color.WHITE);
t1.setBackgroundColor(Color.GRAY);
t2 = new TextView(this);
t2.setTextColor(Color.WHITE);
t2.setBackgroundColor(Color.LTGRAY);
t1.setText(""+vl[i]);
t2.setText(""+(vl[i] * 3.6));
t1.setTypeface(null, 1);
t2.setTypeface(null, 1);
t1.setTextSize(15);
t2.setTextSize(15);
t1.setWidth(200 * dip);
t2.setWidth(200 * dip);
t1.setPadding(20*dip, 0, 0, 0);
row.addView(t1);
row.addView(t2);
accTable.addView(row, new TableLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
}
} catch(NullPointerException e) {
e.printStackTrace();
}
}
public void displayVelocityValues() {
try {
double[] vl = velocity.getVlArray();
for(int i = 0; i<vl.length; i++) { 
Log.d(TAG, "v = " + vl[i] + "mps, "+(vl[i] * 3.6)+ " kmph");
}
} catch(NullPointerException e) {
e.printStackTrace();
}
}
private void calculateAndUpdate() {
final double vel = velocity.getVelocity(linearAcceleration, System.currentTimeMillis());
final double velKmph = vel * 3.6;
//spd.setText("v = "+ velKmph + " kmph");
handler.post(new Runnable() {
public void run() {
//Log.d(getClass().getName().toString(), "Setting velocity = " + velKmph+ " kmph");
spd.setText("v = "+ vel + " mps");
spd_kmph.setText("v = "+ velKmph + " kmph");
}
});
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
//TODO Auto-generated method stub
}
@Override
public void onSensorChanged(SensorEvent event) {
linearAcceleration[0] = event.values[0];
linearAcceleration[1] = event.values[1];
linearAcceleration[2] = event.values[2];        
fillTable(linearAcceleration);
}
}
public class Velocity {
private final String TAG = getClass().getName().toString();
int sampleCounter = 0;
final int totalSamples = 5;
long time0, nAccel;
static int i=0; 
double aDelT0 = 0, v0 = 0, v = 0;
final int totalVelocityValues = 1000;
double []velocityValues = new double[totalVelocityValues];
//float []linearAcceleration = new float[3];
//final int totalAccl = 5;
double []accel = new double[totalSamples];
private double getAvg(double[] a) {
double total = 0;
for(int i = 0; i<a.length; i++) 
total = total + a[i];
return (total / a.length);
}
private double getAcceleration(float[] linearAcceleration) {
return Math.sqrt(Math.pow(linearAcceleration[0], 2) + Math.pow(linearAcceleration[0], 2) + Math.pow(linearAcceleration[0], 2));
}
public double getVelocity(float[] linearAcceleration, long time1) {
//this.linearAcceleration = linearAcceleration;
try {
if(sampleCounter < (totalSamples-1)) {
if(sampleCounter == 0) 
time0 = time1;
accel[sampleCounter] = getAcceleration(linearAcceleration);     
sampleCounter++;    
} else if(sampleCounter == (totalSamples-1)) {
accel[sampleCounter] = getAcceleration(linearAcceleration);
double avgAccel = getAvg(accel);
long timeDelta = ((time1 - time0) / 1000);
double aDelT1 = (avgAccel * timeDelta);
Log.d(TAG, "aDelT1 = "+avgAccel +" * "+timeDelta + " = "+aDelT1 );
v = calculateVelovity(aDelT1);
if(i !=totalVelocityValues) {
velocityValues[i]=v;
i++;
} else {
for(int j=0;j<(totalVelocityValues-1);j++)
velocityValues[j]=velocityValues[j+1];
velocityValues[totalVelocityValues -1]=v;
}
sampleCounter = 0;
}
} catch (Exception e) {
e.printStackTrace();
}
return v;
}
private double calculateVelovity(double aDelT1) {
double v = v0 + (aDelT1 - aDelT0);
Log.d(TAG, "v = "+v0+ "+ ("+aDelT1+" - "+aDelT0+") = "+v);
v0 = v;
aDelT0 = aDelT1;
return v;
}
public double[] getVlArray() {
return velocityValues;
}

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout 
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="@+id/spd"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="5dip"
android:layout_weight="1"
android:background="@android:color/darker_gray"
android:gravity="center_vertical|center_horizontal"
android:text="speed (kmph)"
android:textColor="@android:color/white"
android:textSize="20dip"
android:textStyle="bold"
android:typeface="sans" />
<TextView
android:id="@+id/spd_kmph"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="5dip"
android:layout_weight="1"
android:background="@android:color/darker_gray"
android:gravity="center_vertical|center_horizontal"
android:text="ooooo"
android:textColor="@android:color/white"
android:textSize="20dip"
android:textStyle="bold"
android:typeface="sans" />
<TextView  
android:text="Acceleration Data"
android:textColor="@android:color/white"
android:gravity="center_vertical|center_horizontal"
android:textSize="20dip"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textStyle="bold"
android:layout_marginBottom="5dip"
android:typeface="sans"
android:layout_weight="1"
android:background="@android:color/darker_gray"/>
</LinearLayout>
<LinearLayout android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button android:id="@+id/buttonStart"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_weight="1"
android:text="Start" />
<Button android:id="@+id/buttonClear"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_weight="1"
android:text="Clear" />
<Button android:id="@+id/buttonStop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_weight="1"
android:text="Stop" />
</LinearLayout>
<RelativeLayout android:id="@+id/rl_country_heading"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@android:color/darker_gray">
<TextView android:id="@+id/tv_11"
android:layout_width="70dip"
android:layout_height="wrap_content"
android:gravity="center"
android:text="X"
android:textStyle="normal|bold"
android:textColor="@android:color/white"
android:textSize="18dip">
</TextView>
<TextView android:id="@+id/tv_12"
android:layout_width="150dip"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Y"
android:textStyle="normal|bold"
android:textColor="@android:color/white"
android:textSize="18dip"
android:layout_toRightOf="@+id/tv_11">
</TextView>
<TextView android:id="@+id/tv_13"
android:layout_width="150dip"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Z"
android:textStyle="normal|bold"
android:textColor="@android:color/white"
android:textSize="18dip"
android:layout_toRightOf="@+id/tv_12">
</TextView>
</RelativeLayout>
<LinearLayout android:id="@+id/ll_country"
android:layout_height="fill_parent"
android:layout_width="fill_parent">
<ScrollView android:id="@+id/ScrollView11"
android:layout_width="fill_parent" 
android:layout_height="fill_parent"
android:fillViewport="true">
<LinearLayout android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="5dip">
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" 
android:layout_height="fill_parent"
android:stretchColumns="0,1"
android:id="@+id/country_table"
android:background="@android:color/black">
</TableLayout>  
</LinearLayout>
</ScrollView>
</LinearLayout>

salut @Gaurav avez-vous compris comment faire de la vitesse à l'aide de l'accéléromètre, plutôt que d'utiliser le gps. Si vous avez un peu de code ou de l'échantillon est juste moi, je suis confronté au même problème dans certains endroits, je ne peux pas obtenir la vitesse lorsque le gps n'est pas disponible
Hey!!! Avez-vous obtenir le résultat exact? En fait, je suis à la recherche de la même chose. Avez-vous pensez à la même approche ou essayé d'une autre manière.

OriginalL'auteur Gaurav | 2012-11-07