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{ "id": 23170, "url": "https://patchwork.libcamera.org/api/1.1/patches/23170/?format=api", "web_url": "https://patchwork.libcamera.org/patch/23170/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/1.1/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20250411130423.2164577-4-stefan.klug@ideasonboard.com>", "date": "2025-04-11T13:04:10", "name": "[3/8] libcamera: Add PID controller class", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": false, "hash": "c6771782d51854ab23f397e8e84db02b45395469", "submitter": { "id": 184, "url": "https://patchwork.libcamera.org/api/1.1/people/184/?format=api", "name": "Stefan Klug", "email": "stefan.klug@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/23170/mbox/", "series": [ { "id": 5122, "url": "https://patchwork.libcamera.org/api/1.1/series/5122/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5122", "date": "2025-04-11T13:04:07", "name": "Implement WDR algorithm", "version": 1, "mbox": "https://patchwork.libcamera.org/series/5122/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/23170/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/23170/checks/", "tags": {}, "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "X-Original-To": "parsemail@patchwork.libcamera.org", "Delivered-To": "parsemail@patchwork.libcamera.org", "Received": [ "from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 33C67C3213\n\tfor <parsemail@patchwork.libcamera.org>;\n\tFri, 11 Apr 2025 13:04:38 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id E442268AA8;\n\tFri, 11 Apr 2025 15:04:37 +0200 (CEST)", "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 5B27668A90\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tFri, 11 Apr 2025 15:04:36 +0200 (CEST)", "from ideasonboard.com (unknown\n\t[IPv6:2a00:6020:448c:6c00:5b21:2ad5:1023:7179])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 0C723735;\n\tFri, 11 Apr 2025 15:02:36 +0200 (CEST)" ], "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"WCJoIusD\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1744376557;\n\tbh=TmqTRaOVWD1etF2XOjcJeFWQ1ul6T1CHZaICjXw3c0A=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=WCJoIusD4fscWJmzOWmGUvm2iic0F3HvNIJMy3DOL9K3kCHNaUKsu/uWRfakqgUnF\n\tzT5yxYVfTiNb1ujJ28Dc64Sp/LfTC8TiKSPix5jN79ifhIfGjynP2bHuRZrhRo34TW\n\txkgGxgn1eAVutxRLhnKArkLQPGI/6DzsCXpUAmrE=", "From": "Stefan Klug <stefan.klug@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Cc": "Stefan Klug <stefan.klug@ideasonboard.com>", "Subject": "[PATCH 3/8] libcamera: Add PID controller class", "Date": "Fri, 11 Apr 2025 15:04:10 +0200", "Message-ID": "<20250411130423.2164577-4-stefan.klug@ideasonboard.com>", "X-Mailer": "git-send-email 2.43.0", "In-Reply-To": "<20250411130423.2164577-1-stefan.klug@ideasonboard.com>", "References": "<20250411130423.2164577-1-stefan.klug@ideasonboard.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "A PID controller is a practical and proven solution for many regulation\ntasks. This implementation can be parameterized either using the\nstandard form or normal form [1].\n\nAdditionally output limits can be specified that are used to clamp the\noutput and to prevent integrator windup.\n\n[1]: https://en.wikipedia.org/wiki/Proportional-integral-derivative_controller\n\nSigned-off-by: Stefan Klug <stefan.klug@ideasonboard.com>\n---\n include/libcamera/internal/meson.build | 1 +\n include/libcamera/internal/pid_controller.h | 46 ++++++\n src/libcamera/meson.build | 1 +\n src/libcamera/pid_controller.cpp | 169 ++++++++++++++++++++\n 4 files changed, 217 insertions(+)\n create mode 100644 include/libcamera/internal/pid_controller.h\n create mode 100644 src/libcamera/pid_controller.cpp", "diff": "diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build\nindex 45408b313848..fa4c515332ee 100644\n--- a/include/libcamera/internal/meson.build\n+++ b/include/libcamera/internal/meson.build\n@@ -32,6 +32,7 @@ libcamera_internal_headers = files([\n 'matrix.h',\n 'media_device.h',\n 'media_object.h',\n+ 'pid_controller.h',\n 'pipeline_handler.h',\n 'process.h',\n 'pub_key.h',\ndiff --git a/include/libcamera/internal/pid_controller.h b/include/libcamera/internal/pid_controller.h\nnew file mode 100644\nindex 000000000000..c1212aeb0946\n--- /dev/null\n+++ b/include/libcamera/internal/pid_controller.h\n@@ -0,0 +1,46 @@\n+/* SPDX-License-Identifier: LGPL-2.1-or-later */\n+/*\n+ * Copyright (C) 2025, Ideas On Board Oy\n+ *\n+ * PID Controller\n+ */\n+#pragma once\n+\n+#include <limits>\n+\n+#include <libcamera/base/log.h>\n+\n+namespace libcamera {\n+\n+LOG_DECLARE_CATEGORY(PidController)\n+class PidController\n+{\n+public:\n+\tPidController(double Kp = 1.0, double Ki = 1e6, double Kd = 0.0,\n+\t\t double min = std::numeric_limits<double>::min(),\n+\t\t double max = std::numeric_limits<double>::max());\n+\n+\tvoid setNormalParameters(double Kp = 1.0, double Ki = 1e6, double Kd = 0.0);\n+\tvoid setStandardParameters(double Kp = 1.0, double Ti = 1e6, double Td = 0.0);\n+\tvoid setOutputLimits(double min = std::numeric_limits<double>::min(),\n+\t\t\t double max = std::numeric_limits<double>::max());\n+\tvoid reset();\n+\n+\tvoid setTarget(double target);\n+\tdouble process(double value, double dt = 1.0);\n+\n+private:\n+\tdouble Kp_;\n+\tdouble Ki_;\n+\tdouble Kd_;\n+\tdouble max_;\n+\tdouble min_;\n+\tdouble target_;\n+\n+\tbool clamped_bottom_;\n+\tbool clamped_top_;\n+\tdouble integral_;\n+\tdouble last_error_;\n+};\n+\n+} /* namespace libcamera */\ndiff --git a/src/libcamera/meson.build b/src/libcamera/meson.build\nindex de22b8e60dde..cb9c384d5062 100644\n--- a/src/libcamera/meson.build\n+++ b/src/libcamera/meson.build\n@@ -43,6 +43,7 @@ libcamera_internal_sources = files([\n 'matrix.cpp',\n 'media_device.cpp',\n 'media_object.cpp',\n+ 'pid_controller.cpp',\n 'pipeline_handler.cpp',\n 'process.cpp',\n 'pub_key.cpp',\ndiff --git a/src/libcamera/pid_controller.cpp b/src/libcamera/pid_controller.cpp\nnew file mode 100644\nindex 000000000000..edfa7efafdfd\n--- /dev/null\n+++ b/src/libcamera/pid_controller.cpp\n@@ -0,0 +1,169 @@\n+/* SPDX-License-Identifier: LGPL-2.1-or-later */\n+/*\n+ * Copyright (C) 2025, Ideas on Board Oy\n+ *\n+ * PID controller\n+ */\n+\n+#include \"libcamera/internal/pid_controller.h\"\n+\n+#include <algorithm>\n+\n+#include <libcamera/base/log.h>\n+\n+/**\n+ * \\file pid_controller.h\n+ * \\brief PID controller class\n+ */\n+\n+namespace libcamera {\n+\n+LOG_DEFINE_CATEGORY(PidController)\n+/**\n+ * \\class PidController\n+ * \\brief Implementation of a PID controller\n+ *\n+ * Implementation of a Proportional Integral Derivative controller.\n+ * See https://en.wikipedia.org/wiki/Proportional-integral-derivative_controller\n+ * for the underlying details.\n+ *\n+ */\n+\n+/**\n+ * \\brief Construct a PidController with optional normal parameters\n+ * \\param[in] Kp Proportional gain\n+ * \\param[in] Ki Integral gain\n+ * \\param[in] Kd Derivative gain\n+ * \\param[in] min Minimum output value\n+ * \\param[in] max Maximum output value\n+ *\n+ * For the parameters \\see setNormalParameters() and \\see setOutputLimits().\n+ */\n+PidController::PidController(double Kp, double Ki, double Kd, double min, double max)\n+{\n+\treset();\n+\tsetNormalParameters(Kp, Ki, Kd);\n+\tsetOutputLimits(min, max);\n+}\n+\n+/**\n+ * \\brief Set the normal parameters\n+ * \\param[in] Kp Proportional gain\n+ * \\param[in] Ki Integral gain\n+ * \\param[in] Kd Derivative gain\n+ *\n+ * Set the normal parameters of the PID controller.\n+ */\n+void PidController::setNormalParameters(double Kp, double Ki, double Kd)\n+{\n+\tKp_ = Kp;\n+\tKi_ = Ki;\n+\tKd_ = Kd;\n+}\n+\n+/**\n+ * \\brief Set the standard parameters\n+ * \\param[in] Kp Proportional gain\n+ * \\param[in] Ti Integration time constant\n+ * \\param[in] Td Derivative time constant\n+ *\n+ * Set the standard parameters of the PID controller. Functionally it is\n+ * identical to the normal parameters but has the added benefit that it is\n+ * easier to understand the values. The \\a Ti parameter specifies the time the\n+ * controller will tolerate the output value to be away from the target. Td is\n+ * the time in which the controller tries to approach the target value.\n+ *\n+ * \\see https://en.wikipedia.org/wiki/Proportional-integral-derivative_controller#Standard_form\n+ */\n+void PidController::setStandardParameters(double Kp, double Ti, double Td)\n+{\n+\tKp_ = Kp;\n+\tKi_ = Kp / Ti;\n+\tKd_ = Kp / Td;\n+}\n+\n+/**\n+ * \\brief Set the output limits\n+ * \\param[in] min Minimum output value\n+ * \\param[in] max Maximum output value\n+ *\n+ * Set the minimum and maximum output values of the controller. The controller\n+ * will clamp the output to these values and ensure that no windup of the\n+ * integral part occurs.\n+ */\n+void PidController::setOutputLimits(double min, double max)\n+{\n+\tmin_ = min;\n+\tmax_ = max;\n+}\n+\n+/**\n+ * \\brief Reset the controller\n+ *\n+ * Reset the internal state of the controller.\n+ */\n+void PidController::reset()\n+{\n+\tlast_error_ = 0;\n+\tintegral_ = 0;\n+\tclamped_bottom_ = false;\n+\tclamped_top_ = false;\n+}\n+\n+/**\n+ * \\brief Set the target value\n+ * \\param[in] target Target value\n+ *\n+ * Set the target value the controller shall reach. In controller theory this is\n+ * usually called the set point.\n+ */\n+void PidController::setTarget(double target)\n+{\n+\ttarget_ = target;\n+}\n+\n+/**\n+ * \\brief Run a regulation step\n+ * \\param[in] value Measured value\n+ * \\param[in] dt Time since last call\n+ * \\return Output value\n+ *\n+ * Process the last measurement (also called process variable PV) and return the\n+ * new regulation value. The \\a dt parameter specifies the time since the last\n+ * call. It defaults to 1.0, so in cases that are not time but frame based, it\n+ * can be left out.\n+ */\n+double PidController::process(double value, double dt)\n+{\n+\tdouble error = target_ - value;\n+\tdouble derivative = (error - last_error_) / dt;\n+\n+\t/* If we hit a limit disable the integrative part in that direction */\n+\tif ((error * Ki_ > 0 && !clamped_top_) ||\n+\t (error * Ki_ < 0 && !clamped_bottom_))\n+\t\tintegral_ += error * dt;\n+\n+\tdouble ret = Kp_ * error + Ki_ * integral_ + Kd_ * derivative;\n+\n+\tclamped_top_ = false;\n+\tif (ret >= max_) {\n+\t\tclamped_top_ = true;\n+\t\tret = max_;\n+\t}\n+\n+\tclamped_bottom_ = false;\n+\tif (ret <= min_) {\n+\t\tclamped_bottom_ = true;\n+\t\tret = min_;\n+\t}\n+\n+\tLOG(PidController, Debug) << \"Value: \" << value << \", Target: \" << target_\n+\t\t\t\t << \", Error: \" << error << \", Integral: \" << integral_\n+\t\t\t\t << \", Derivative: \" << derivative << \", Output: \" << ret;\n+\n+\tlast_error_ = error;\n+\n+\treturn ret;\n+}\n+\n+} /* namespace libcamera */\n", "prefixes": [ "3/8" ] }