Embedded low level control of DC motors for actuating robotic legs

In this paper an embedded system for accurate control of torque, speed and position of DC motors which actuate the joints of a robotic leg is presented. The proposed embedded system is not based on dedicated and expensive motor controllers but on a general pourpose embedded board equipped with a 32bit microcontroller. For each motor the embedded system can selectively operate in three different control modes: torque, speed and position, to control concurrently at least three DC motorswith different control tasks. Each motor is simply equipped with a rotatory encoder and a low-cost current sensor which provides measures of velocity and current as feedback signals. The experimental results show that the embedded controlleris able to regulate the motor variables with interesting timeresponses. Although the embedded controller was designed forthe proposed robotic application, it is applicable to other systems where the concurrent control of several DC-motors is required.