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 motors with different control tasks. Each motor is simply equipped with a rotary encoder and a low-cost current sensor which provide measurements of velocity and current as feedback signals. The experimental results show that the embedded controller is able to regulate the motor variables as expected by simulation results. Although the embedded controller was designed for the proposed robotic application, it is applicable to other systems where the concurrent control of several DC-motors is required.