Added Derate Factor code to AMS interface

lib/interfaces/include/AMSInterface.h

@@ -60,7 +60,8 @@ class AMSInterface
     float get_filtered_max_cell_temp();
     /* IIR filter and return filtered min cell voltage */
     float get_filtered_min_cell_voltage();
-
+    /*gets the derate factor for acc system*/
+    float get_acc_derate_factor();
     //RETRIEVE CAN MESSAGES//
     /* read BMS status messages */
     void retrieve_status_CAN(unsigned long curr_millis, CAN_message_t &recvd_msg);
@@ -94,6 +95,7 @@ class AMSInterface
     float filtered_min_cell_voltage;
     float cell_temp_alpha;
     float cell_voltage_alpha;
+    float acc_derate_factor;
 };
 
 #endif /* __AMSINTERFACE_H__ */

lib/interfaces/src/AMSInterface.cpp

@@ -57,6 +57,33 @@ float AMSInterface::get_filtered_max_cell_temp() {
     return filtered_max_cell_temp;
 }
 
+float AMSInterface::get_acc_derate_factor() {
+    float voltage_lim_factor = 1.0;
+    float startDerateVoltage = 3.5;
+    float endDerateVoltage = 3.2;
+    float voltage_lim_max = 1;
+    float voltage_lim_min = 0.2;
+
+    float temp_lim_factor = 1.0;
+    float startDerateTemp = 50;
+    float stopDerateTemp = 58;
+    float temp_lim_max = 1;
+    float temp_lim_min = 0.2;
+
+    float filtered_min_cell_voltage = get_filtered_min_cell_voltage();
+    //float_map equivalient because new code is bad 
+    voltage_lim_factor = (filtered_min_cell_voltage - startDerateVoltage) * (voltage_lim_min - voltage_lim_max) / (endDerateVoltage - startDerateVoltage) + voltage_lim_max;
+    voltage_lim_factor = max(min(voltage_lim_max, voltage_lim_factor), voltage_lim_min);
+
+    temp_lim_factor = (filtered_max_cell_temp - startDerateTemp) * (temp_lim_min - temp_lim_max) / (stopDerateTemp - startDerateTemp) + temp_lim_max;
+    temp_lim_factor = max(min(temp_lim_factor, temp_lim_max), temp_lim_min);
+
+    acc_derate_factor = min(temp_lim_factor,voltage_lim_factor);
+    return acc_derate_factor;
+}
+
+}
+
 float AMSInterface::get_filtered_min_cell_voltage() {
     bms_low_voltage = bms_voltages_.get_low() / 10000.0;
     filtered_min_cell_voltage = filtered_min_cell_voltage * cell_temp_alpha + (1.0 - cell_voltage_alpha) * bms_low_voltage;