ITK Engineering Develops IEC 62304–Compliant Controller for Dental Drill Motor with Model-Based Design

Dental drill motors operate at speeds up to 40,000 RPM. The field-oriented control algorithm for such motors needs precise information about the rotor position over a wide speed range. In a sensorless motor, rotor position must be deduced from changes in current in the stator caused by electromagnetic induction from the rotor magnet. ITK engineers needed to design and optimize a rotor position estimator, as well as a sophisticated cascade control for the dental drill motor that would comply with the IEC 62304 standard for medical device software.

当项目开始时，原型电动机不可用。为了满足客户的项目截止日期，ITK必须与电动机硬件并行开发控制器软件。ITK工程师需要创建一个准确的电动机模型，并开发与该模型一起使用的控制器。电动机可用后，他们需要在嵌入式处理器上快速实施和测试其控制软件。

ITK engineers designed, optimized, implemented, and tested the sensorless BLDC motor controller with Model-Based Design.

工程师从数据表中工作的现有电动机和客户提供的信息，在Simulink中对BLDC电机（包括其电气和机械组件）进行了建模万博1manbetx^®。

他们在simulink中开发了一个控制器模型，并使用了状态流万博1manbetx^®to model startup, shutdown, and error modes, as well as user-selectable operating modes.

The team ran closed-loop simulations of the plant model and the initial controller model, which relied on a rotor position signal supplied by the plant model.

为了开发转子位置估计器，该团队使用符号数学工具箱™求解代数方程，然后完善估计器，直到其结果与工厂模型的实际转子位置信号匹配。

Using the automatic scaling and data type override capabilities of Fixed-Point Designer™, the engineers converted their floating-point controller design to fixed point. They reran simulations to verify the fixed-point model.

团队开发了MATLAB^®对单个模型组件进行批处理单元测试的脚本。他们使用Simulink Coverage™为这些测试生成了模型覆盖报告。万博1manbetx

该团队通过嵌入式编码器从其控制器模型中生成了5000多行的C代码^®。他们编译了手臂的代码^®Cortex^®-M3 processor with a Keil compiler.

工程师在原型板和电动机上测试了控制器，精炼了模型并重新生成代码以优化性能。

ITK将控制器和工厂的Sim万博1manbetxulink模型以及生成的生产代码以及其客户提供。控制器和无传感器BLDC电动机目前正在牙科钻头中进行串联生产。