农用全方位移动平台控制系统设计

发布时间：2018-01-05 19:31

本文关键词：农用全方位移动平台控制系统设计　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着农业生产的技术发展,农用机器人得到了越来越广泛的应用。由于农业作业环境的复杂性和非结构性,面向果园、蔬菜生产基地的农业机器人应用还比较有限。农业环境下作业要求作业装备具有很好的灵活性和适应性。因此,研究高度灵活的工作平台及其控制系统是实现农业自动化作业和智能作业的首要条件。本文结合提出的主动万向轮式农用全方位移动平台结构方案设计了一种基于运动控制卡的嵌入式控制系统,进行了相关理论和试验研究,为开发果园、蔬菜等农业环境下自动作业装备奠定基础。主要工作内容包括:(一)首先通过分析国内外先进的全方位移动平台,提出基于DSP运动控制卡PCI-1285为核心的控制方案。然后选择永磁无刷直流电动机作为驱动电动机、混合式步进电动机作为转向电动机,完成相关的硬件电路设计,其中包括驱动电动机的电源电路、驱动电路、保护电路等。最后在此基础上,设计了基于Common Motion Utility开发环境的软件系统,其中包括系统参数初始化、系统故障检测、中断子程序等。(二)首先通过分析永磁无刷直流电动机的工作原理,采用两两导通的驱动方式并建立其数学模型。然后研究了其调速原理,经推导得到其转速传递函数,根据其转速传递函数及本文实际工作控制需求,确定了PWM脉宽调制的调速方法。最后通过分析五种PWM脉宽调制方式对换相转矩波动的影响,确定了pwm-on调制方式。(三)首先对农用全方位移动平台控制策略进行分析,通过比较转矩控制和电流控制确定驱动系统采用转速、电流双闭环控制方式。然后分析移动平台转向时稳定性,根据运行速度分为同相控制和逆相控制两种控制模式。最后根据移动平台实际工作主要为低速运行(35km/h),基于逆相控制模式分析其电子差速原理,并利用三角函数及比例法等数学工具推导其差速计算公式。(四)首先利用MATLAB提供的动态系统仿真工具Simulink对本文提出的永磁无刷直流电动机转速、电流双闭环控制系统进行仿真。根据仿真得到的相电流、电磁转矩、转速波形证明该控制系统基本能够完成控制要求。最后结合Simulink仿真结果对驱动电动机进行试验,检测其空载线电压、带载线电压、带载相电流以及在踏板位置传感器不同开度时电动机的转速。实验结果表明控制器反应迅速,基本能够完成控制要求,并根据在踏板位置传感器不同开度时电动机的转速的实际检测结果,计算分别在正、反转时每个电动机电压与转速的线性关系表达式,为移动平台整车控制分配加速信号提供理论基础。
[Abstract]:With the development of agricultural production technology, agricultural robots have been more and more widely used. Because of the complexity and non-structure of agricultural operating environment, it is oriented to orchard. The application of agricultural robots in vegetable production base is still limited. In the agricultural environment, the operating equipment is required to have good flexibility and adaptability. The study of highly flexible working platform and its control system is the most important condition to realize agricultural automation and intelligent operation. This paper designs a basic structure of active universal wheeled agricultural omnidirectional mobile platform. Embedded control system based on motion control card. The related theory and experimental research were carried out to lay the foundation for the development of automatic operating equipment in the agricultural environment such as orchards vegetables and so on. The main contents include: (1) through the analysis of the advanced omnidirectional mobile platform at home and abroad. This paper presents a control scheme based on DSP motion control card PCI-1285, and then selects permanent magnet brushless DC motor as driving motor and hybrid stepping motor as steering motor. Complete the related hardware circuit design, including the drive motor power circuit, driving circuit, protection circuit. Finally, on this basis. A software system based on Common Motion Utility development environment is designed, which includes system parameter initialization and system fault detection. First of all, by analyzing the working principle of permanent magnet brushless DC motor, adopting the driving mode of two pairs of conductors and establishing its mathematical model, and then studying the principle of speed regulation of permanent magnet brushless DC motor. The rotational speed transfer function is derived, according to its rotational speed transfer function and the actual work control requirements of this paper. The speed regulation method of PWM pulse width modulation is determined. Finally, the influence of five PWM pulse width modulation modes on commutation torque ripple is analyzed. Pwm-on modulation mode. (3) firstly, the control strategy of agricultural omnidirectional mobile platform is analyzed, and the speed of driving system is determined by comparing torque control with current control. Current double closed loop control mode. Then the stability of mobile platform steering is analyzed. According to the running speed, it can be divided into two control modes: in-phase control and inverse phase control. Finally, according to the actual work of the mobile platform, it is mainly running at a low speed of 35km / h, and the electronic differential speed principle is analyzed based on the inverse phase control mode. The differential calculation formula is derived by using trigonometric function and proportion method. (4). At first, the speed of permanent magnet brushless DC motor (PMSM) proposed in this paper is studied by using Simulink, a dynamic system simulation tool provided by MATLAB. The current double closed loop control system is simulated. According to the phase current and electromagnetic torque obtained by simulation. The rotational speed waveform proves that the control system can basically fulfill the control requirements. Finally, combined with the Simulink simulation results, the driving motor is tested to detect the no-load line voltage and the line voltage with load. The experimental results show that the controller can respond rapidly and can basically fulfill the control requirements. According to the actual test results of the motor speed when the pedal position sensor has different opening degree, the linear expression of the voltage and speed of each motor is calculated respectively in positive and reverse. It provides a theoretical basis for vehicle control and distribution of acceleration signals on mobile platform.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273

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