Design of an electronic odometer for DC motors

What is it about?

The paper proposes an innovative electronic sensor for odometry in mobile robotics. The sensor is based on the measurement of current peaks caused by the commutation of a DC electric motor. The signal is preprocessed by analog filters, then digital processing in the microcontroller is applied. The sensor utilizes a small low-power MCU AtTiny44 and provides an SPI interface for communication with the master robot controller. The main advantage of the proposed sensor is the lack of any mechanical parts, which results in high durability. The sensor has been simulated in Simulink and then a fully-functional sample was created and tested.

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Photo by Denis Cosmin on Unsplash

Photo by Denis Cosmin on Unsplash

Why is it important?

Measuring the position and speed of a motor is widely required in both the robotics and automotive industry. The proposed sensor is capable to detect the position of a DC motor in a wide interval of RPM. It does not require any mechanical components to be installed onto the shaft of the motor, therefore it is especially suitable for usage in applications where the dimensions of the motor are limited or the existing construction does not allow to add another type (mechanical, magnetic, optic) of the encoder. The proposed filtering and signal processing techniques were successfully verified using a hardware prototype. The solution can be scaled by a different choice of the current measurement resistor.