基于遗传算法与模糊推理的智能DSP控制器及在仿生人工腿中的应用

【作者】 李安平；

【导师】 谭冠政；

【作者基本信息】 中南大学 ， 控制理论与控制工程， 2003， 硕士

【摘要】 智能人工腿是机器人学和生物医学工程学领域一个备受关注的研究课题，它将智能控制理论、微电子技术、计算机控制技术、机械设计与制造及生物医学工程等技术融合在一起。它的优点是其步行速度可自然、随意地跟随截肢者步行速度的变化而变化。开展该项目的研究对帮助那些截肢者回归主流社会，减轻社会及其家庭负担具有重要意义。 智能人工腿主要由膝关节、控制膝关节屈伸运动及小腿摆动的执行机构、踝关节、脚以及智能控制器等组成，其最关键部件是控制膝关节屈伸运动及小腿摆动的执行机构和智能控制器。目前，在国外研制成功的智能人工腿中，控制膝关节屈伸运动及小腿摆动的执行机构是一个单级空压气缸，其内有一个针阀(节流阀)，通过调节针阀的开度可控制气缸阻尼，从而控制小腿摆动的速度。而智能控制器主要由小型电机、传感器以及微处理器组成，用于调节针阀的开度。从目前公开的资料看，在国外新型智能人工腿中，用于控制针阀开度的控制器是开环控制方式，其控制精度不高，且不具有智能化策略。 在论文中，我们对国外智能人工腿控制器的控制方式进行了改进，将其控制方式设计成闭环方式，并引入模糊控制理论，改变了控制器的控制策略，提高了控制器的控制精度。而控制器的参数则利用遗传算法优化得到。遗传算法操作简单、全局搜索能力强，能够在很广的解空间内搜索出一组最优参数。而传统参数整定方法是依据于经验反复试凑获得，其整定过程异常繁琐。本文用到的遗传算法是由作者自行设计的伪并行遗传算法，该算法是对基本遗传算法的改进，在收敛速度和全局搜索能力方面远远优于基本遗传算法。文中详细地介绍了利用该算法优化控制器参数的具体过程，并给出了寻优仿真结果。在智能人工腿控制器的硬件设计中，选用了TI公司生产的TMS320F240芯片。该芯片面向新一代电机调速，它将DSP高速运算能力与面向电机的高效控制能力集于一体。TMS320F240芯片丰富的指令和内部特有的硬件结构，给智能控制器的软件和硬件设计带来了极大的方便。在该芯片中编制控制算法实现对针阀开度快速、精确控制。更多还原

【Abstract】 Intelligent artificial leg has become an interesting research project in the fields of robotics and biomedical engineering. It incorporates the technology of intelligent control, microelectronics, computer control, mechanical design & manufacture and biomedical engineering, etc. Its excellent performance is that its walking speed can naturally change with the change of amputee’s walking speed. The significance of this research is that it can help amputees return to mainstream society aind it can lighten society and family’s burden.Intelligent artificial leg consists of knuckle, an executive mechanism, an anklebone, a foot and an intelligent controller. The executive mechanism controls the bent and stretch’s movement of knuckle and the pendular movement of calf. The key components of the intelligent artificial leg are the executive mechanism and the intelligent controller. Today, in the foreign intelligent artificial leg, the executive mechanism which controls the bent and stretch’s movement of knuckle and the pendular movement of calf is a single air cylinder. In the air cylinder, there is a throttle, the cylinder’s damp can be adjusted by controlling the opening of the throttle valve, when the air cylinder’s damp changes, the pendular speed of calf will change too. The intelligent controller consists of micro-motor, sensor and microprocessor. It is used to regulate the opening of throttle. From the current public information, in the new type of the foreign intelligent artificial leg, the way, which controls the bent and stretch’s movement of knuckle and the pendular movement of calf, is open-loop, this kind of control way has no enough high precision and has no intelligent control strategy.In this paper, the control way of foreign intelligent leg’s controller has been improved and a close-loop control way has been proposed. At the same time, fuzzy control theory is applied to this controller, the control strategy has been changed and precision of control has been greatly raised. We use genetic algorithm to determine the parameters of controller. Genetic algorithm’s operation is simple and has powerful ability of global search. This kind of algorithm can find out optimal answers in an extensive answer space. However the traditional way is based on people’s experience, and the process of determining parameters is very difficult. The genetic algorithm proposed in this paper is called pseudo parallel genetic algorithm, which is designed by author. This kind of search way improves the basic genetic algorithm. In the speed of search and the ability of global search, the pseudo genetic algorithm is superior to basic genetic algorithm. We describe the process of optimizing controller’s parameters by this way in detail. In the design of the controller’s hardware, we choose TMS320F240 produced by TI company. It gathers DSP with high speed operational ability and the effective control ability. The rich instructions of this chip and its specialhardware structure bring great convenience to the hardware design of the intelligent controller. In this chip, we program control algorithm and realize the quick and accurate control of the opening of throttle valve.更多还原