From 52e2aecaf19fbbcc8cbc7303a55f6be55998fe29 Mon Sep 17 00:00:00 2001
From: Matthias Grob <maetugr@gmail.com>
Date: Thu, 19 Oct 2017 11:41:02 +0200
Subject: [PATCH] Battery: simplify linear voltage relation, currently
neglecting the real world voltage drop under load
---
src/modules/systemlib/battery.cpp | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/src/modules/systemlib/battery.cpp b/src/modules/systemlib/battery.cpp
index e71299f19f..af34fa293a 100644
--- a/src/modules/systemlib/battery.cpp
+++ b/src/modules/systemlib/battery.cpp
@@ -40,6 +40,7 @@
*/
#include "battery.h"
+#include <mathlib/mathlib.h>
Battery::Battery() :
SuperBlock(nullptr, "BAT"),
@@ -181,13 +182,10 @@ Battery::estimateRemaining(float voltage_v, float current_a, float throttle_norm
bat_v_empty_dynamic -= _param_v_load_drop.get() * thr;
}
- // the range from full to empty is the same for batteries under load and without load,
- // since the voltage drop applies to both the full and empty state
- const float voltage_range = (_param_v_full.get() - _param_v_empty.get());
-
// remaining battery capacity based on voltage
- const float rvoltage = (voltage_v - (_param_n_cells.get() * bat_v_empty_dynamic))
- / (_param_n_cells.get() * voltage_range);
+ const float cell_voltage = voltage_v / _param_n_cells.get();
+ const float rvoltage = math::gradual(cell_voltage, _param_v_empty.get(), _param_v_full.get(), 0.f, 1.f);
+
const float rvoltage_filt = _remaining_voltage * 0.99f + rvoltage * 0.01f;
if (PX4_ISFINITE(rvoltage_filt)) {
--
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