hysteresis related issue in mcconf and mcpwm_foc.c

Hi,

I am having hard time understanding what does macro MCCONF_FOC_SL_OPENLOOP_HYST and m_min_rpm_hyst_timer variable do?

what is the meaning of hysteresis here?

what does the section of code given below do?

float openloop_rpm_max = utils_map(fabsf(motor->m_motor_state.iq_filter),

0.0, motor->m_conf->l_current_max,

motor->m_conf->foc_openloop_rpm_low * motor->m_conf->foc_openloop_rpm,

motor->m_conf->foc_openloop_rpm);

utils_truncate_number_abs(&openloop_rpm_max, motor->m_conf->foc_openloop_rpm);

float openloop_rpm = openloop_rpm_max;

if (motor->m_conf->foc_sensor_mode != FOC_SENSOR_MODE_ENCODER) {

float time_fwd = t_lock + t_ramp + t_const - motor->m_min_rpm_timer;

if (time_fwd < t_lock) {

openloop_rpm = 0.0;

} else if (time_fwd < (t_lock + t_ramp)) {

openloop_rpm = utils_map(time_fwd, t_lock,

t_lock + t_ramp, 0.0, openloop_rpm);

}

}

what is t_lock, t_ramp, and t_const?

please help me understand this section of code and these parameters.

Thanks.