Add stepwise controller
This adds the ability to use stepwise curves alongside
pid control. This creates a base controller class that
pidcontroller and stepwise controller inherit from.
Note: Hysteresis to come in follow-on patch
Tested-by:
Created a stepwise controller and noticed that when it
crossed a threshold that it contributed to the pwm setting.
Change-Id: I6cf842f80eaccafc905d620970afe91e2092d568
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/pid/ec/stepwise.cpp b/pid/ec/stepwise.cpp
new file mode 100644
index 0000000..4246fb3
--- /dev/null
+++ b/pid/ec/stepwise.cpp
@@ -0,0 +1,45 @@
+/*
+// Copyright (c) 2018 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+*/
+
+#include "stepwise.hpp"
+
+#include <cstddef>
+#include <limits>
+
+namespace ec
+{
+float stepwise(const ec::StepwiseInfo& info, float input)
+{
+ float value = info.output[0]; // if we are below the lowest
+ // point, we set the lowest value
+
+ for (size_t ii = 1; ii < ec::maxStepwisePoints; ii++)
+ {
+
+ if (info.reading[ii] == std::numeric_limits<float>::quiet_NaN())
+ {
+ break;
+ }
+ if (info.reading[ii] > input)
+ {
+ break;
+ }
+ value = info.output[ii];
+ }
+
+ return value;
+}
+} // namespace ec
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