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1 | /*********************************************************************************/ |
1 | /*********************************************************************************/ |
2 | /* Attitude sense system (processing of gyro, accelerometer and altimeter data) */ |
2 | /* Attitude sense system (processing of gyro, accelerometer and altimeter data) */ |
3 | /*********************************************************************************/ |
3 | /*********************************************************************************/ |
4 | 4 | ||
5 | #ifndef _ATTITUDE_H |
5 | #ifndef _ATTITUDE_H |
6 | #define _ATTITUDE_H |
6 | #define _ATTITUDE_H |
7 | 7 | ||
8 | #include <inttypes.h> |
8 | #include <inttypes.h> |
9 | 9 | ||
10 | #include "analog.h" |
10 | #include "analog.h" |
11 | 11 | ||
12 | // For debugging only. |
12 | // For debugging only. |
13 | #include "uart0.h" |
13 | #include "uart0.h" |
14 | 14 | ||
15 | /* |
15 | /* |
16 | * If you have no acc. sensor or do not want to use it, remove this define. This will cause the |
16 | * If you have no acc. sensor or do not want to use it, remove this define. This will cause the |
17 | * acc. sensor to be ignored at attitude calibration. |
17 | * acc. sensor to be ignored at attitude calibration. |
18 | */ |
18 | */ |
19 | #define ATTITUDE_USE_ACC_SENSORS yes |
19 | #define ATTITUDE_USE_ACC_SENSORS yes |
20 | 20 | ||
21 | /* |
21 | /* |
22 | * The frequency at which numerical integration takes place. 488 in original code. |
22 | * The frequency at which numerical integration takes place. 488 in original code. |
23 | */ |
23 | */ |
24 | #define INTEGRATION_FREQUENCY 488 |
24 | #define INTEGRATION_FREQUENCY 488 |
25 | 25 | ||
26 | /* |
26 | /* |
27 | * Gyro readings are divided by this before being used in attitude control. This will scale them |
27 | * Gyro readings are divided by this before being used in attitude control. This will scale them |
28 | * to match the scale of the stick control etc. variables. This is just a rough non-precision |
28 | * to match the scale of the stick control etc. variables. This is just a rough non-precision |
29 | * scaling - the below definitions make precise conversion factors. |
29 | * scaling - the below definitions make precise conversion factors. |
30 | * Will be about 4 for InvenSense, 8 for FC1.3 and 8 for ADXRS610. |
30 | * Will be about 4 for InvenSense, 8 for FC1.3 and 8 for ADXRS610. |
31 | * The number 1250 is derived from the original code: It has about 225000 = 1250 * 180 for 180 degrees. |
31 | * The number 1250 is derived from the original code: It has about 225000 = 1250 * 180 for 180 degrees. |
32 | */ |
32 | */ |
33 | #define HIRES_GYRO_INTEGRATION_FACTOR 1 |
33 | #define HIRES_GYRO_INTEGRATION_FACTOR 1 |
34 | // (int)((GYRO_RATE_FACTOR_PITCHROLL * INTEGRATION_FREQUENCY * GYRO_PITCHROLL_CORRECTION) / 1250) |
34 | // (int)((GYRO_RATE_FACTOR_PITCHROLL * INTEGRATION_FREQUENCY * GYRO_PITCHROLL_CORRECTION) / 1250) |
35 | 35 | ||
36 | /* |
36 | /* |
37 | * Constant for deriving an attitude angle from acceleration measurement. |
37 | * Constant for deriving an attitude angle from acceleration measurement. |
38 | * |
38 | * |
39 | * The value is derived from the datasheet of the ACC sensor where 5g are scaled to VRef. |
39 | * The value is derived from the datasheet of the ACC sensor where 5g are scaled to VRef. |
40 | * 1g is (3V * 1024) / (5 * 3V) = 205 counts. The ADC ISR sums 2 acc. samples to each |
40 | * 1g is (3V * 1024) / (5 * 3V) = 205 counts. The ADC ISR sums 2 acc. samples to each |
41 | * [pitch/roll]AxisAcc and thus reads about acc = 410 counts / g. |
41 | * [pitch/roll]AxisAcc and thus reads about acc = 410 counts / g. |
42 | * We approximate a small pitch/roll angle v by assuming that the copter does not accelerate: |
42 | * We approximate a small pitch/roll angle v by assuming that the copter does not accelerate: |
43 | * In this explanation it is assumed that the ADC values are 0 based, and gravity is included. |
43 | * In this explanation it is assumed that the ADC values are 0 based, and gravity is included. |
44 | * The sine of v is the far side / the hypothenusis: |
44 | * The sine of v is the far side / the hypothenusis: |
45 | * sin v = acc / sqrt(acc^2 + acc_z^2) |
45 | * sin v = acc / sqrt(acc^2 + acc_z^2) |
46 | * Using that v is a small angle, and the near side is about equal to the the hypothenusis: |
46 | * Using that v is a small angle, and the near side is about equal to the the hypothenusis: |
47 | * sin v ~= acc / acc_z |
47 | * sin v ~= acc / acc_z |
48 | * Assuming that the helicopter is hovering at small pitch and roll angles, acc_z is about 410, |
48 | * Assuming that the helicopter is hovering at small pitch and roll angles, acc_z is about 410, |
49 | * and sin v ~= v (small angles, in radians): |
49 | * and sin v ~= v (small angles, in radians): |
50 | * sin v ~= acc / 410 |
50 | * sin v ~= acc / 410 |
51 | * v / 57.3 ~= acc / 410 |
51 | * v / 57.3 ~= acc / 410 |
52 | * v ~= acc * 57.3 / 410 |
52 | * v ~= acc * 57.3 / 410 |
53 | * acc / v ~= 410 / 57.3 ~= 7, that is: There are about 7 counts per degree. |
53 | * acc / v ~= 410 / 57.3 ~= 7, that is: There are about 7 counts per degree. |
54 | * |
54 | * |
55 | * Summary: DEG_ACC_FACTOR = (2 * 1024 * [sensitivity of acc. meter in V/g]) / (3V * 57.3) |
55 | * Summary: DEG_ACC_FACTOR = (2 * 1024 * [sensitivity of acc. meter in V/g]) / (3V * 57.3) |
56 | */ |
56 | */ |
57 | #define DEG_ACC_FACTOR 7 |
57 | #define DEG_ACC_FACTOR 7 |
58 | 58 | ||
59 | /* |
59 | /* |
60 | * Growth of the integral per degree: |
60 | * Growth of the integral per degree: |
61 | * The hiResXXXX value per deg / s * INTEGRATION_FREQUENCY samples / sec * correction / a number divided by |
61 | * The hiResXXXX value per deg / s * INTEGRATION_FREQUENCY samples / sec * correction / a number divided by |
62 | * HIRES_GYRO_INTEGRATION_FACTOR (why???) before integration. |
62 | * HIRES_GYRO_INTEGRATION_FACTOR (why???) before integration. |
63 | * The value of this expression should be about 1250 (by setting HIRES_GYRO_INTEGRATION_FACTOR to something suitable). |
63 | * The value of this expression should be about 1250 (by setting HIRES_GYRO_INTEGRATION_FACTOR to something suitable). |
64 | */ |
64 | */ |
65 | #define GYRO_DEG_FACTOR_PITCHROLL (GYRO_RATE_FACTOR_PITCHROLL * INTEGRATION_FREQUENCY * GYRO_PITCHROLL_CORRECTION / HIRES_GYRO_INTEGRATION_FACTOR) |
65 | #define GYRO_DEG_FACTOR_PITCHROLL (GYRO_RATE_FACTOR_PITCHROLL * INTEGRATION_FREQUENCY * GYRO_PITCHROLL_CORRECTION / HIRES_GYRO_INTEGRATION_FACTOR) |
66 | #define GYRO_DEG_FACTOR_YAW (GYRO_RATE_FACTOR_YAW * INTEGRATION_FREQUENCY * GYRO_YAW_CORRECTION) |
66 | #define GYRO_DEG_FACTOR_YAW (GYRO_RATE_FACTOR_YAW * INTEGRATION_FREQUENCY * GYRO_YAW_CORRECTION) |
67 | 67 | ||
68 | /* |
68 | /* |
69 | * This is ([gyro integral value] / degree) / (degree / acc. sensor value) = gyro integral value / acc.sensor value |
69 | * This is ([gyro integral value] / degree) / (degree / acc. sensor value) = gyro integral value / acc.sensor value |
70 | * = the factor an acc. sensor should be multiplied by to get the gyro integral |
70 | * = the factor an acc. sensor should be multiplied by to get the gyro integral |
71 | * value for the same (small) angle. |
71 | * value for the same (small) angle. |
72 | * The value is about 200. |
72 | * The value is about 200. |
73 | */ |
73 | */ |
74 | #define GYRO_ACC_FACTOR ((GYRO_DEG_FACTOR_PITCHROLL) / (DEG_ACC_FACTOR)) |
74 | #define GYRO_ACC_FACTOR ((GYRO_DEG_FACTOR_PITCHROLL) / (DEG_ACC_FACTOR)) |
75 | 75 | ||
76 | #define PITCHROLLOVER180 ((int32_t)GYRO_DEG_FACTOR_PITCHROLL * 180) |
76 | #define PITCHROLLOVER180 ((int32_t)GYRO_DEG_FACTOR_PITCHROLL * 180) |
77 | #define PITCHROLLOVER360 ((int32_t)GYRO_DEG_FACTOR_PITCHROLL * 360) |
77 | #define PITCHROLLOVER360 ((int32_t)GYRO_DEG_FACTOR_PITCHROLL * 360) |
78 | #define YAWOVER360 ((int32_t)GYRO_DEG_FACTOR_YAW * 360) |
78 | #define YAWOVER360 ((int32_t)GYRO_DEG_FACTOR_YAW * 360) |
79 | 79 | ||
80 | /* |
80 | /* |
81 | * Rotation rates |
81 | * Rotation rates |
82 | */ |
82 | */ |
83 | extern int16_t rate_PID[2], rate_ATT[2], yawRate; |
83 | extern int16_t rate_PID[2], rate_ATT[2], yawRate; |
84 | extern int16_t differential[3]; |
84 | extern int16_t differential[3]; |
85 | 85 | ||
86 | /* |
86 | /* |
87 | * Attitudes calculated by numerical integration of gyro rates |
87 | * Attitudes calculated by numerical integration of gyro rates |
88 | */ |
88 | */ |
89 | extern int32_t angle[2]; |
89 | extern int32_t angle[3]; |
90 | - | ||
91 | // extern volatile int32_t ReadingIntegralTop; // calculated in analog.c |
- | |
92 | - | ||
93 | /* |
- | |
94 | * Compass navigation |
- | |
95 | */ |
- | |
96 | extern int16_t compassHeading; |
- | |
97 | extern int16_t compassCourse; |
- | |
98 | // extern int16_t compassOffCourse; |
- | |
99 | extern uint8_t compassCalState; |
- | |
100 | extern int32_t yawGyroHeading; |
90 | extern int32_t error[3]; |
101 | extern uint8_t updateCompassCourse; |
- | |
102 | extern uint16_t ignoreCompassTimer; |
- | |
103 | 91 | ||
104 | /* |
92 | /* |
105 | * Dynamic gyro offsets. These are signed values that are subtracted from the gyro measurements, |
93 | * Dynamic gyro offsets. These are signed values that are subtracted from the gyro measurements, |
106 | * to help canceling out drift and vibration noise effects. The dynamic offsets themselves |
94 | * to help canceling out drift and vibration noise effects. The dynamic offsets themselves |
107 | * can be updated in flight by different ways, for example: |
95 | * can be updated in flight by different ways, for example: |
108 | * - Just taking them from parameters, so the pilot can trim manually in a PC or mobile tool |
96 | * - Just taking them from parameters, so the pilot can trim manually in a PC or mobile tool |
109 | * - Summing up how much acc. meter correction was done to the gyro integrals over the last n |
97 | * - Summing up how much acc. meter correction was done to the gyro integrals over the last n |
110 | * integration, and then adding the sum / n to the dynamic offset |
98 | * integration, and then adding the sum / n to the dynamic offset |
111 | * - Detect which way the pilot pulls the stick to keep the copter steady, and correct by that |
99 | * - Detect which way the pilot pulls the stick to keep the copter steady, and correct by that |
112 | * - Invent your own... |
100 | * - Invent your own... |
113 | */ |
101 | */ |
114 | extern int16_t dynamicOffset[2], dynamicOffsetYaw; |
102 | extern int16_t dynamicOffset[2], dynamicOffsetYaw; |
115 | 103 | ||
116 | /* |
104 | /* |
117 | * For NaviCtrl use. |
105 | * For NaviCtrl use. |
118 | */ |
106 | */ |
119 | extern int16_t averageAcc[2], averageAccCount; |
107 | extern int16_t averageAcc[2], averageAccCount; |
120 | 108 | ||
121 | /* |
109 | /* |
122 | * Re-init flight attitude, setting all angles to 0 (or to whatever can be derived from acc. sensor). |
110 | * Re-init flight attitude, setting all angles to 0 (or to whatever can be derived from acc. sensor). |
123 | * To be called when the pilot commands gyro calibration (eg. by moving the left stick up-left or up-right). |
111 | * To be called when the pilot commands gyro calibration (eg. by moving the left stick up-left or up-right). |
124 | */ |
112 | */ |
125 | void attitude_setNeutral(void); |
113 | void attitude_setNeutral(void); |
126 | 114 | ||
127 | /* |
115 | /* |
128 | * Experiment. |
116 | * Experiment. |
129 | */ |
117 | */ |
130 | // void attitude_startDynamicCalibration(void); |
118 | // void attitude_startDynamicCalibration(void); |
131 | // void attitude_continueDynamicCalibration(void); |
119 | // void attitude_continueDynamicCalibration(void); |
132 | 120 | ||
133 | int32_t getAngleEstimateFromAcc(uint8_t axis); |
121 | int32_t getAngleEstimateFromAcc(uint8_t axis); |
134 | 122 | ||
135 | /* |
123 | /* |
136 | * Main routine, called from the flight loop. |
124 | * Main routine, called from the flight loop. |
137 | */ |
125 | */ |
138 | void calculateFlightAttitude(void); |
126 | void calculateFlightAttitude(void); |
139 | #endif //_ATTITUDE_H |
127 | #endif //_ATTITUDE_H |
140 | 128 |