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Motor Controllers: Making Automobiles Much More Than a Set of Wheels

With electric vehicles making their presence felt in the global automotive market, the discussion on electric motors has shifted completely towards the EV powertrain. Understandably so, since electric motor and motor controllers have replaced the mighty internal combustion engines that have been driving automobiles since their invention.

However, electric motors have also been widely used in hundreds of automotive components. The use of small motors in automobiles can be traced back to the early 20th century.

The Ford Model T, for example, used a small electric motor to power its horn. Over the years, the use of small motors and actuator systems has become more prevalent in automotive design. Today, these systems are used in almost every aspect of automotive operation, from power windows to engine control.

As the modern automobile is embracing automation in every way possible, the role of electric motors has become even larger. For instance, your regular seats have become automated and can now adjust themselves to your favorite seating position.

Even the humble parking brake now comes in its electronic avatar. Several technologies are at play making these automations possible, but at the core of it all is an electric motor and a motor control system. These are small motors that go unnoticed but play a huge role in ensuring comfort and ease of driving.

All of this sounds great, but why are we suddenly discussing small motors and motor controllers?

The short answer to the question is that these motors are quite important, and their advancement helps build better automobiles. The longer answer to the question is what we will explore in the subsequent sections of the blog.

So, let’s start by asking the question,

How Do Small Motors and Actuator Systems Impact Overall Driving Experience?

Small motors and actuator systems are ubiquitous in a vehicle and play a crucial role in the overall driving experience. These systems are responsible for controlling various functions such as windows, mirrors, doors, and seats. They also play a critical role in safety features such as airbags, ABS brakes, and stability control systems.

At every moment spent in a modern vehicle, there is some sort of human interaction with a motor. A driver using the electronic steering wheel is being assisted by a small motor driven by a smart motor control system. The algorithm embedded inside the motor controller has been designed to understand the optimum amount of torque provided to the steering wheel.

Here are some ways in which small motors and actuator systems impact the driving experience:

  • Enhanced comfort and convenience: Small motors and actuator system allow for easy adjustment of seats, windows, and mirrors, making it easier to find a comfortable driving position. This enhances the overall driving experience by reducing fatigue and making long drives more comfortable.
  • Safety of the vehicle occupants: Actuator systems such as airbags, ABS brakes, and stability control systems are essential safety features in modern automobiles. They use small motors to deploy the airbags quickly and accurately or activate the braking system, enhancing safety and reducing the risk of accidents.
  • Overall vehicle performance: Small motors and actuator systems are also critical to the performance of the automobile. For example, the engine control module uses small motors to control the amount of fuel injected into the engine, ensuring optimal performance and fuel efficiency.

Looking at the functionality perspective of the motors alone will not give a clear picture of how they are actually able to perform their task. Its imperative that we delve a little deeper and understand,

How Control Algorithms and Application Programs Work Together to Drive Actuator System?

Let’s take an example of a seat control ECU. The electric motor that moves the seat is mostly a DC motor driven by a motor control system. If we go into technical aspects of a motor controller, especially its software, there are two major components- control algorithm and applications programs.

  1. Control algorithms: Control algorithms are sets of rules or instructions that govern how the motor operates. They are typically implemented using software and run on a microcontroller or other digital processing unit. Control algorithms take input from various sensors in the vehicle, such as the accelerator pedal position, engine speed, and vehicle speed, and use this information to adjust the motor’s operation accordingly.

    The most common control algorithms used to drive automotive motors are Field control algorithm and field weakening control.

  2. Application programs: Application programs are software modules that interact with control algorithms to achieve specific functions, such as controlling the engine speed, or the torque delivered to the wheels. Application programs may also incorporate other features such as fuel injection management, emissions control, and other functions that help to optimize the motor’s performance.

Taking the example of a seating control ECU again, some of the common application programs are:

  • Soft Start/Stop: Soft start/stop is an application program that provides a smooth and gradual acceleration and deceleration of the seat motor. It is designed to minimize jerky movements and provide a more comfortable ride.
  • Seat Memory: This application allows the driver and passengers to store and recall their preferred seating positions. This feature is commonly used in vehicles with multiple drivers or passengers to ensure that the seat position can be quickly and easily adjusted to the user’s preferences.

Similarly, for an electronic power steering, the application programs that work together with motor control algorithms comprise:

  • Variable steering assist: Variable steering assist is an application program that adjusts the level of assistance provided by the EPS system based on the vehicle speed, steering angle, and other factors.
  • Lane keeping assist: Lane keeping assist is an application program that uses sensors to detect the vehicle’s position within the lane and provides steering assistance to keep the vehicle centered in the lane.

The amazing things an actuator system in an automobile performs are only due to the sophisticated control algorithms that work in tandem with advanced application programs.


Whether it is comfort, convenience, safety or performance, there is mostly an electric motor or motors helping to achieve them. The automotive industry as a whole has taken immense strides in advancements in the development of motor control algorithms as well as applications to support modern features.

However, the dream of a fully autonomous car or migration to vehicles with fully automated functions takes more than just a few strides in motor controller technology. The combined use of AI, machine learning, sensor technologies, semiconductors, etc. is going to take us where we visualise the automotive industry to be in the future.


About the Author

Vaibhav is a digital-marketing professional with a deep-rooted interest in everything automotive. Regular collaborations with automotive tech guys keep him apprised of all new trends in the automotive industry. Besides digital marketing, Vaibhav is fond of writing and music.

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