Electric motors convert electrical energy into mechanical energy that can power machines, tools, and vehicles. They have two mechanical components, a fixed stator and a moving rotor, and two electrical components, a set of permanent magnets and an armature. They are commonly found in blowers and pumps, disk drives, household appliances, electric fans, and electric cars. In some cases, they are used as generators during regenerative braking to recover lost energy that would otherwise be wasted as heat and friction.
Electric motors operate at high efficiency, converting a large percentage of electrical energy into mechanical energy. They are quiet and do not produce exhaust fumes, making them ideal for indoor or enclosed spaces. They also provide instant torque, which is helpful in applications such as turning or lifting objects.
There are many different types of electric motors. Each has its own advantages and disadvantages. One of the most popular is the DC brushless motor, which has a series of brushes that connect to the commutator. It then flips the direction of current flow to allow the electromagnet to rotate. This type of motor is simple and inexpensive, but it is not as efficient as a traditional induction motor.
An AC induction motor has a stator made of steel alloy laminations that are wound with wire to make induction coils. It also has a rotor, which is a gear-shaped iron piece that contains a shaft. The rotor is powered by an electric current from three phases of a power supply. When the rotor is spinning, it creates magnetic fields that attract or repel the poles of the electromagnet. These magnetic fields rotate the rotor, generating mechanical energy that powers the motor.
The DC brushed motor (DCM) has been the mainstay of electric vehicles since the late nineteenth century, but it is not as efficient or as quiet as newer motors. It also needs a lot of maintenance and has low life expectancy. However, recent innovations in motor design have made DCMs more useful. For example, it was recently used in a robotic cheetah that runs and jumps without the need for a complex hydraulic system.
Adaptive control algorithms handle system uncertainties by adjusting the controller online, which leads to strong robustness and disturbance rejection. These control methods also have fast transient response, which is important for applications that require frequent start-and-stop operation. Among these is model reference adaptive control, which uses a precise motor model and an adjustable system to optimize controller performance. Another approach is model-based robust control, which uses an external driver to compute a motor model and then adjusts the controller parameters online. In both of these systems, the objective is to minimize the sensitivity of the motor parameter perturbations to maintain optimal controller performance.