Similar articles

Abstract: As kinematic calculations are complicated, it takes a long time and is difficult to get the desired accurate result with a single processor in real-time motion control of multi-degree-of-freedom (MDOF) systems. Another calculation unit is needed, especially with the increase in the degree of freedom. The main central processing unit (CPU) has additional loads because of numerous motion elements which move independently from each other and their closed-loop controls. The system designed is also complicated because there are many parts and cabling. This paper presents the design and implementation of a hardware that will provide solutions to these problems. It is realized using the Very High Speed Integrated Circuit Hardware Description Language (VHDL) and field-programmable gate array (FPGA). This hardware is designed for a six-legged robot and has been working with servo motors controlled via the serial port. The hardware on FPGA calculates the required joint angles for the feet positions received from the serial port and sends the calculated angels to the servo motors via the serial port. This hardware has a co-processor for the calculation of kinematic equations and can be used together with the equipment that would reduce the electromechanical mess. It is intended to be used as a tool which will accelerate the transition from design to application for robots.

多自由度系统运动学方程求解的VHDL应用

针对多自由度系统的运动学计算复杂，在实时运动控制中，单处理器下获取计算结果耗费较长时间，且难以获取期望的精确结果，本文引入协处理器增加系统自由度。设计硬件并实现其在六足机器人运动中的应用。 引入协处理器增加系统自由度，分担主处理器负载。 根据六足机器人机械结构（图1）建立运动学方程。选择合适的串口、电机、芯片结构（图6）。用VHDL语言编写程序并在FPGA上测试。 设计运动学协处理器用于六足机器人关节角度的计算。该协处理器包含内部串行端口，可与具有内部控制器和串口的电机配合使用。设计的硬件将运算得到的关节角度通过串口发送至六足机器人。并可以通过串口从主处理器获取必要的参数来计算关节角度。用VHDL语言编写并在FPGA上测试。所设计的硬件亦可以应用于其他机器人。
多自由度系统；运动学；协处理器；串行通信；六足机器人

[1]Axelson, J., 2007. Serial Port Complete: COM Ports, USB Virtual COM Ports, and Ports for Embedded Systems (2nd Ed.). Lakeview Research.

[2]Barron-Zambrano, J.H., Torres-Huitzil, C., Girau, B., 2012. Configurable embedded CPG-based control for robot locomotion. Int. J. Adv. Robot. Syst., 9:92.1-92.12.

[3]Erkol, H.O., Demirel, H., 2013. A serial port hardware design and application by FPGA. Turkish National Meeting on Automatic Control, p.132-135 (in Turkish).

[4]Fang, Y., Chen, X., 2011. Design and simulation of UART serial communication module based on VHDL. Proc. 3rd Int. Workshop on Intelligent Systems and Applications, p.1-4.

[5]Fongjun, T., Tantaworrasilp, A., Kwansud, P., et al., 2011. Automatic multi channel serial I/O interface using FPGA. Proc. SICE Annual Conf., p.864-867.

[6]Hani, M.K., Wen, H.Y., Paniandi, A., 2006. Design and implementation of a private and public key crypto processor for next-generation IT security applications. Malaysian J. Comput. Sci., 19(1):29-45.

[7]Idris, M.Y.I., Yaacob, M., Razak, Z., 2006. A VHDL implementation of UART design with BIST capability. Malaysian J. Comput. Sci., 19(1):73-86.

[8]Juang, Y.S., Sung, T.Y., Ko, L.T., et al., 2013. FPGA implementation of a CORDIC-based joint angle processor for a climbing robot. Int. J. Adv. Robot. Syst., 10:195.1-195.6.

[9]Mahapatra, A., Roy, S.S., 2009. Computer aided dynamic simulation of six-legged robot. Int. J. Recent Trends Eng., 2(2):146-151.

[10]Murray, R.M., Li, Z., Sastry, S.S., 1994. A Mathematical Introduction to Robotic Manipulation. CRC Press, Boca Raton, Florida, USA.

[11]Pa, P.S., Wu, C.M., 2012. Design of a hexapod robot with a servo control and a man-machine interface. Robot. Comput.-Integr. Manuf., 28(3):351-358.

[12]Roennau, A., Kerscher, T., Dillmann, R., 2010. Design and kinematics of a biologically-inspired leg for a six-legged walking machine. Proc. 3rd IEEE RAS and EMBS Int. Conf. on Biomedical Robotics and Biomechatronics, p.626-631.

[13]Sandoval-Castro, X.Y., Garcia-Murillo, M., Perez-Resendiz, L.A., et al., 2013. Kinematics of hex-piderix—a six-legged robot—using screw theory. Int. J. Adv. Robot. Syst., 10:19.1-19.8.

[14]Shih, T.S., Tsai, C.S., Her, I., 2012. Comparison of alternative gaits for multiped robots with severed legs. Int. J. Adv. Robot. Syst., 9:157.1-157.8.

[15]Siciliano, B., Sciavicco, L., Villani, L., et al., 2009. Robotics Modelling, Planning and Control. Springer, London, UK.

[16]Taira, T., Kamata, N., Yamasaki, N., 2005. Design and implementation of reconfigurable modular humanoid robot architecture. IEEE/RSJ Int. Conf. on Intelligent Robots and Systems, p.3566-3571.

[17]Zheng, Y., Liu, J., Kan, J., 2012. An optimal kinematics calculation method for a multi-DOF manipulator. Przegląd Elektrotechn., 88(7b):320-323.

[18]Zhu, W., Lamarche, T., Dupuis, E., et al., 2013. Precision control of modular robot manipulators: the VDC approach with embedded FPGA. IEEE Trans. Robot., 29(5):1162-1179.