Use linux-mpu9150 DMP functions to retrieve position data. Remove old POC code.

pull/167/head
Christopher Young 2015-12-27 16:11:21 -05:00
rodzic 9f66732bfb
commit a35e3cb76f
2 zmienionych plików z 46 dodań i 171 usunięć

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@ -366,7 +366,6 @@ func processNMEALine(l string) bool {
}
}
if x[2] != "A" { // invalid fix
return false
}
@ -458,7 +457,7 @@ func initBMP180() error {
}
func initMPU6050() error {
myMPU6050 = mpu6050.New(i2cbus) //TODO: error checking.
myMPU6050 = mpu6050.New() //TODO: error checking.
return nil
}

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@ -3,83 +3,49 @@
package mpu6050
import (
"math"
"time"
// "github.com/golang/glog"
"github.com/kidoman/embd"
"../linux-mpu9150/mpu"
"log"
"time"
)
//https://www.olimex.com/Products/Modules/Sensors/MOD-MPU6050/resources/RM-MPU-60xxA_rev_4.pdf
const (
address = 0x68
GYRO_XOUT_H = 0x43
GYRO_YOUT_H = 0x45
GYRO_ZOUT_H = 0x47
ACCEL_XOUT_H = 0x3B
ACCEL_YOUT_H = 0x3D
ACCEL_ZOUT_H = 0x3F
PWR_MGMT_1 = 0x6B
GYRO_CONFIG = 0x1B
ACCEL_CONFIG = 0x1C
ACCEL_SCALE = 16384.0 // Assume AFS_SEL = 0.
GYRO_SCALE = 131.0 // Assume FS_SEL = 0.
pollDelay = 500 * time.Microsecond // 2000Hz
pollDelay = 98 * time.Millisecond // ~10Hz
)
type XYZ struct {
x float32
y float32
z float32
}
// MPU6050 represents a InvenSense MPU6050 sensor.
type MPU6050 struct {
Bus embd.I2CBus
Poll time.Duration
started bool
//TODO
gyro_reading XYZ // "Integrated".
accel_reading XYZ // Directly from sensor.
pitch float64
roll float64
// Calibration variables.
calibrated bool
pitch_history []float64
roll_history []float64
pitch_resting float64
roll_resting float64
pitch float64
roll float64
heading float64
// gyro chan XYZ
// accel chan XYZ
calibrated bool
// For tracking heading (mixing GPS track and the gyro output).
heading float64 // Current heading.
last_gyro_heading float64 // Last reading directly from the gyro for comparison with current heading.
last_gyro_heading_valid bool
quit chan struct{}
}
// New returns a handle to a MPU6050 sensor.
func New(bus embd.I2CBus) *MPU6050 {
n := &MPU6050{Bus: bus, Poll: pollDelay}
func New() *MPU6050 {
n := &MPU6050{Poll: pollDelay}
n.StartUp()
return n
}
//TODO
func (d *MPU6050) StartUp() error {
d.Bus.WriteByteToReg(address, PWR_MGMT_1, 0) // Wake device up.
d.Bus.WriteByteToReg(address, GYRO_CONFIG, 0) // FS_SEL = 0
d.Bus.WriteByteToReg(address, ACCEL_CONFIG, 0) // AFS_SEL = 0
mpu.InitMPU()
d.pitch_history = make([]float64, 0)
d.roll_history = make([]float64, 0)
@ -90,6 +56,8 @@ func (d *MPU6050) StartUp() error {
return nil
}
/*
func (d *MPU6050) calibrate() {
//TODO: Error checking to make sure that the histories are extensive enough to be significant.
//TODO: Error checking to do continuous calibrations.
@ -110,127 +78,37 @@ func (d *MPU6050) calibrate() {
d.calibrated = true
}
func (d *MPU6050) readGyro() (XYZ, error) {
var ret XYZ
*/
x, err := d.Bus.ReadWordFromReg(address, GYRO_XOUT_H)
if err != nil {
return ret, err
func normalizeHeading(h float64) float64 {
for h < float64(0.0) {
h = h + float64(360.0)
}
y, err := d.Bus.ReadWordFromReg(address, GYRO_YOUT_H)
if err != nil {
return ret, err
for h >= float64(360.0) {
h = h - float64(360.0)
}
z, err := d.Bus.ReadWordFromReg(address, GYRO_ZOUT_H)
if err != nil {
return ret, err
}
ret.x = float32(int16(x)) / GYRO_SCALE // º/sec
ret.y = float32(int16(y)) / GYRO_SCALE // º/sec
ret.z = float32(int16(z)) / GYRO_SCALE // º/sec
return ret, nil
return h
}
func (d *MPU6050) readAccel() (XYZ, error) {
var ret XYZ
func (d *MPU6050) getMPUData() {
p, r, h, err := mpu.ReadMPU()
x, err := d.Bus.ReadWordFromReg(address, ACCEL_XOUT_H)
if err != nil {
return ret, err
if err == nil {
d.pitch = float64(p)
d.roll = float64(r)
// Calculate the change in direction from current and previous IMU reading.
if d.last_gyro_heading_valid {
h2 := float64(h)
this_change := h2 - d.last_gyro_heading
d.heading = normalizeHeading(d.heading + this_change)
}
d.last_gyro_heading_valid = true
d.last_gyro_heading = float64(h)
} else {
log.Printf("mpu6050.calculatePitchAndRoll(): mpu.ReadMPU() err: %s\n", err.Error())
}
y, err := d.Bus.ReadWordFromReg(address, ACCEL_YOUT_H)
if err != nil {
return ret, err
}
z, err := d.Bus.ReadWordFromReg(address, ACCEL_ZOUT_H)
if err != nil {
return ret, err
}
ret.x = float32(int16(x)) / ACCEL_SCALE
ret.y = float32(int16(y)) / ACCEL_SCALE
ret.z = float32(int16(z)) / ACCEL_SCALE
return ret, nil
}
func (d *MPU6050) calculatePitchAndRoll() {
accel := d.accel_reading
// log.Printf("accel: %f, %f, %f\n", accel.x, accel.y, accel.z)
// Accel.
p1 := math.Atan2(float64(accel.y), dist(accel.x, accel.z))
p1_deg := p1 * (180.0 / math.Pi)
r1 := math.Atan2(float64(accel.x), dist(accel.y, accel.z))
r1_deg := -r1 * (180.0 / math.Pi)
// Gyro.
p2 := float64(d.gyro_reading.x)
r2 := float64(d.gyro_reading.y) // Backwards?
// "Noise filter".
ft := float64(0.98)
sample_period := float64(1 / 2000.0)
d.pitch = float64(ft*(sample_period*p2+d.pitch) + (1-ft)*p1_deg)
d.roll = float64((ft*(sample_period*r2+d.roll) + (1-ft)*r1_deg))
if !d.calibrated {
d.pitch_history = append(d.pitch_history, d.pitch)
d.roll_history = append(d.roll_history, d.roll)
}
//FIXME: Experimental (heading).
f := math.Atan2(float64(d.gyro_reading.z), dist(float32(d.pitch), float32(d.roll)))
h1_deg := -float64(3.42857142857)*f * (180.0 / math.Pi)
// d.heading = float64((float64(3.42857142857)*sample_period * float64(-d.gyro_reading.z)) + d.heading)
d.heading = float64((sample_period * h1_deg) + d.heading)
if d.heading > 360.0 {
d.heading = d.heading - float64(360.0)
} else if d.heading < 0.0 {
d.heading = d.heading + float64(360.0)
}
}
func (d *MPU6050) measureGyro() error {
XYZ_gyro, err := d.readGyro()
if err != nil {
return err
}
d.gyro_reading = XYZ_gyro
return nil
}
func (d *MPU6050) measureAccel() error {
XYZ_accel, err := d.readAccel()
if err != nil {
return err
}
d.accel_reading = XYZ_accel
return nil
}
func (d *MPU6050) measure() error {
if err := d.measureGyro(); err != nil {
return err
}
if err := d.measureAccel(); err != nil {
return err
}
return nil
}
func dist(a, b float32) float64 {
a64 := float64(a)
b64 := float64(b)
return math.Sqrt((a64 * a64) + (b64 * b64))
}
// Temperature returns the current temperature reading.
@ -246,16 +124,14 @@ func (d *MPU6050) Run() {
go func() {
d.quit = make(chan struct{})
timer := time.NewTicker(d.Poll)
calibrateTimer := time.NewTicker(1 * time.Minute)
// calibrateTimer := time.NewTicker(1 * time.Minute)
for {
select {
case <-timer.C:
d.measureGyro()
d.measureAccel()
d.calculatePitchAndRoll()
case <-calibrateTimer.C:
d.calibrate()
calibrateTimer.Stop()
d.getMPUData()
// case <-calibrateTimer.C:
// d.calibrate()
// calibrateTimer.Stop()
case <-d.quit:
return
}