diff options
Diffstat (limited to 'src/modules/systemlib/pid/pid.c')
| -rw-r--r-- | src/modules/systemlib/pid/pid.c | 38 |
1 files changed, 24 insertions, 14 deletions
diff --git a/src/modules/systemlib/pid/pid.c b/src/modules/systemlib/pid/pid.c index 4996a8f66..77c952f52 100644 --- a/src/modules/systemlib/pid/pid.c +++ b/src/modules/systemlib/pid/pid.c @@ -51,6 +51,8 @@ #include "pid.h" #include <math.h> +#define SIGMA 0.000001f + __EXPORT void pid_init(PID_t *pid, float kp, float ki, float kd, float intmax, float limit, uint8_t mode, float dt_min) { @@ -165,20 +167,26 @@ __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, flo d = 0.0f; } - // Calculate the error integral and check for saturation - i = pid->integral + (error * dt); + if (pid->ki > 0.0f) { + // Calculate the error integral and check for saturation + i = pid->integral + (error * dt); - if (fabsf((error * pid->kp) + (i * pid->ki) + (d * pid->kd)) > pid->limit || - fabsf(i) > pid->intmax) { - i = pid->integral; // If saturated then do not update integral value - pid->saturated = 1; + if ((pid->limit > SIGMA && (fabsf((error * pid->kp) + (i * pid->ki) + (d * pid->kd)) > pid->limit)) || + fabsf(i) > pid->intmax) { + i = pid->integral; // If saturated then do not update integral value + pid->saturated = 1; - } else { - if (!isfinite(i)) { - i = 0.0f; + } else { + if (!isfinite(i)) { + i = 0.0f; + } + + pid->integral = i; + pid->saturated = 0; } - pid->integral = i; + } else { + i = 0.0f; pid->saturated = 0; } @@ -186,11 +194,13 @@ __EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, flo float output = (error * pid->kp) + (i * pid->ki) + (d * pid->kd); if (isfinite(output)) { - if (output > pid->limit) { - output = pid->limit; + if (pid->limit > SIGMA) { + if (output > pid->limit) { + output = pid->limit; - } else if (output < -pid->limit) { - output = -pid->limit; + } else if (output < -pid->limit) { + output = -pid->limit; + } } pid->last_output = output; |