This paper presents a legged-wheeled hybrid robotic vehicle that uses a combination of rigid and non-rigid joints, allowing it to be more impact-tolerant. The robot has four legs, each one with three degrees of freedom. Each leg has two non-rigid rotational joints with completely passive components for damping and accumulation of kinetic energy, one rigid rotational joint, and a driving wheel. Each leg uses three independent DC motors—one for each joint, as well as a fourth one for driving the wheel. The four legs have the same position configuration, except for the upper hip joint. The vehicle was designed to be modular, low-cost, and its parts to be interchangeable. Beyond this, the vehicle has multiple operation modes, including a low-power mode. Across this article, the design, modeling, and control stages are presented, as well as the communication strategy. A prototype platform was built to serve as a test bed, which is described throughout the article. The mechanical design and applied hardware for each leg have been improved, and these changes are described. The mechanical and hardware structure of the complete robot is also presented, as well as the software and communication approaches. Moreover, a realistic simulation is introduced, along with the obtained results.

At the present time, digital signal processing algorithms use elementary operations such as addition, subtraction, multiplication and division. Using the elementary operations more complex algorithms can be implemented. In the case of inverse square root operation ( 2 / 1 a ) there are direct instructions to calculate it in "C" language, however, the processing time of these instructions is very large compared with the processing time of basic instructions, because their algorithms are complicated. Another aspect to consider is the used hardware; in particular, the memory is consumed very much, for this reason it is necessary to design faster firmware to obtain optimal performance in digital signal processing algorithms.In this paper, an algorithm to calculate the inverse square root operation in Fixed-Point arithmetic is implemented in a microcontroller using Newton-Raphson Method and Least Squares Method. The goal is to reduce the processing time compared with the required processing time used in Floating-Point arithmetic.Index Terms-Firmware, fixed-point, inverse square root algorithm, microcontroller.

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