Mechatronic approach facilitates automotive electric motor control

June 25, 2012 // By Giovanni Torrisi
Giovanni Torrisi, STMicroelectronics explains how a mechatronic control architecture can simplify the electrical distribution system, improve quality and reliability to lead to reduced power consumption and emissions.

In the latest generation of cars, there are many applications that require merging electronics and mechanical actuators in order to simplify the automotive electrical distribution system, improve electronics quality and reliability, and to reduce C02 emissions. Mechatronic approaches help reach those targets by dealing with the fully integrated and optimized design of an entire system, including sensors, actuators, mechanics, electronic components, and all the data processing signals required (i.e., control of the "internal system," communication with external "entities" by means of physical layers, or simply, generic, data transferring). A very simplified diagram of a typical mechatronic approach is shown below.

From safety critical applications to comfort related ones, most automotive applications may benefit from this synergistic integration, and the use of mechatronics has even increased in recent years. In fact, it is abundantly used in cars, and is found in more than 15 systems, including keyless entry, fully integrated rear-view mirrors, climate control, adaptive front lighting, ABS brakes, electric power steering, and many others.

Within the DC motor control area (window lift, steering column lock, sunroof, and smart motor connectors, etc.), mechatronic approaches are multiplying. This is because, on top of the above mentioned needs for the merging of electronics and mechanics, this approach brings additional advantages.

Traditional centralized topologies, in which the control unit is located far from the actuator, need very distant connections (wiring) and a high number of different interconnect technologies including rivets, solder, wiring, and joints. Having lengthy power connections leads to unnecessary power waste, less than optimized EMC performance (due to stray components), and an overall less compact solution. A typical mechatronics solution, in which a single electronic module has been constructed using a multi-chip module and "connectorized" for compact and simple interfacing with a motor housing, would usually have many less interconnections than the traditional solution.

A typical mechatronics implementation for a simple, low cost, DC motor control is illustrated below.

The SUPPLY signals

Design category: