难以控制

A control scheme for room temperature control in Variable Air Volume air-conditioning system is presented in this paper.

1控制系统的设计方案变风量空调系统是一种新型、节能的空调方式，但在我国却难以推广。

Because of the non-linearity, time- variability, multi-parameter, intense coupling of the heating process and especially, the random interfere and anfractuosity of process, precision mathematics model is difficult to be established. The routine PID algorithm can not meet the requirement of control.

高岭土回转窑的加热过程中存在非线性、时变性、多参数强烈耦合这些问题，且随机干扰以及过程机理错综复杂，难以建立被控对象的精确数学模型，采用常规的PID算法很难达到控制要求。

With the new concept,the problem of variable structure control of 2D discrete system is transferred to the problem of seeking a sliding model with good sporting character and attractability. The concrete design schemes of the imitative sliding model and variable structure controller are also put forward. And the concrete expression of the time T in ε-neighborhood of reaching switch manifold is obtained. The difficulty of applying the existing methods to MIMO systems is overcome.

在新概念之下，将2D离散系统的变结构控制问题转化为寻找一个既具有良好的运动品质又具有吸引性的滑动模问题，给出了滑动模及变结构控制器的设计方案，并且获得了达到切换流形的ε领域的时间T的具体表达式，克服了已有方法难以应用到多输入—多输出系统上的困难。

Coal-pulverizing systems with ball mill and storage banker have characteristis of strong coupling , nonlinearity, time-varying systems, and great changes in operating condition s.

钢球磨煤机中间储仓式制粉系统具有多变量强耦合、强非线性、工况变化大的特性，长期以来难以投入自动控制，因此成为电力行业自动控制研究的热点问题。

The performance of general PID controller used in CPP system is usually hard to be the best.

船舶调距桨控制系统中采用一般PID控制器往往难以达到最佳控制效果。

Soft Sensor Technique is an effective approach which is used to solve some actual puzzles, caused by the unavailability of measurers in the controlling process variables measuring or the high price of measurers, in industrial process control systems.

软测量技术为解决工业控制系统在线检测过程中，一些控制参数无法通过检测仪表进行直接检测或由于检测仪表价格昂贵难以应用等实际难题提供了有效技术手段。

The design of yaw rate tracking control system a rchitecture by using μ synthesis robust control is presented and the weight ing f unctions are selected.

车辆总是承担不同的载荷，车辆建模亦存在着误差，传统四轮转向控制器难以达到原有的性能指标；针对外界干扰，采用μ综合鲁棒控制方法，构造横摆角速度跟踪综合控制系统设计框架，选取了不同环节的权函数。

Aiming at the engineering problem that K welding machine is used to weld PD3 60kg/m rail during welding production at present, the quality of the joint falls short of the standard of TB/T1632-91 because of the objection of grey-spots in the welding joint, this paper analyses the element which influence the welding joint quality in detail from the stability of flash of the accelerating step of the rail, finds out the relationship between the stability of flash-butt welding and the quality of rail joint, provides the measure for controlling the quality of rail welding and some gist for establishing perfect controlling system of welding joint quality

针对目前焊轨生产中采用K型焊机焊接PD3 60kg/m钢轨，接头灰斑缺陷多，性能难以达到部颁标准要求的工程问题，对材质、焊接电压、焊接工艺对接头质量的影响进行研究，并从钢轨焊接加速烧化阶段的闪光稳定性入手，详细分析了影响接头质量的因素，找出了钢轨闪光焊稳定性与质量的关系，提出了控制钢轨焊接质量的措施，为建立完善的焊接质量控制体系提供了依据。

For example temperature's inertia is great, it's time-lag is serious and it is difficult to establish accurate mathematical model of the object.

温度是工业控制的主要被控参数之一，可是由于温度自身的一些特点，如惯性大，滞后现象严重，难以建立精确的数学模型等，给控制过程带来了难题。

For example temperature's inertia is great,it's time-lag is serious and it is difficult to establish accurate mathematical model of the object.

温度是电热水暖控制的主要被控参数之一，可是由于温度自身的一些特点，如惯性大，滞后现象严重，难以建立精确的数学模型等，给控制过程带来了难题。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。