Implementation of two-level algorithms using fixed-point arithmetic

The effect of using fixed-point arithmetic in the digital implementation of two-level control algorithms is examined in this paper. Analytical expressions are developed to predict the change in the expected minimum cost and associated matrices. It is shown that there is a favourable match between the analytical predictions and averaged simulation experiments. The use of finite-precision machines increases the expected theoretical minimum cost and makes the two-level algorithm become slow and thus require excessive iterations to converge.     

Performance degradation in digitally implemented optimal regulators using fixed-point arithmetic

A technique to analytically predict the degradation in performance of an optimal regulator control law implementation with precomputed control gains using fixed-point arithmetic is presented here. The analytical predictions are compared with an actual system response using simulation studies. Extensions of this error analysis for a stochastic control law implementation is also developed.     

Implementation of universal computer arithmetic with optimal accuracy

Mathematical structures such as intervals, vectors and matrices are only insufficiently considered by the usual computer arithmetic. In this paper a general and modular concept for computer arithmetic is proposed which finally covers all spaces occurring in numerical computations (see figure 1). The operations are performed following a uniform construction principle. It induces a set of mapping properties between real and rounded operations which by the way guarantees optimal accuracy.     

Elimination of overflow oscillations in fixed-point state-space digital filters using saturation arithmetic: An LMI approach

A criterion for the nonexistence of overflow oscillations in fixed-point state-space digital filters employing saturation arithmetic is presented. The criterion possesses the structure of linear matrix inequality and hence is computationally tractable. The criterion is compared with an earlier LMI-based criterion.     

Stability of fixed-point state-space digital filters using two’s complement arithmetic: Further insight

The purpose of this note is to point out that for the digital filters using two’s complement arithmetic, the criterion in (Singh, 2010) can be transformed into a simpler form; the stability criteria in Singh (2010) and Mills et al. (1978) are equivalent in some cases. A third-order example in which Singh’s criterion is satisfied and Mills–Mullis–Roberts criterion fails is presented.     

Duality of linear fixed-point smoothing and fixed-time control

This paper considers the duality of linear fixed-point smoothing and fixed-time quadratic regulator problems in which the quadratic cost functional is positive definite with respect to control. It is further shown that the dual of the fixed-point smoothing algorithms in coloured measurement noise is the fixed-time regulator in which the quadratic cost functional is restricted to be non-negative definite.     

An improved criterion for the global asymptotic stability of fixed-point state-space digital filters with saturation arithmetic

A criterion for the global asymptotic stability of fixed-point state-space digital filters with saturation arithmetic is presented. The criterion makes use of the structural properties of the multiple saturation nonlinearities in greater detail than several existing criteria. The relationship between the presented criterion and some existing ones is established. Through the relationship, it is clear that the presented criterion is less conservative than corresponding existing results, which is confirmed by a numerical example.     

A fixed-point iteration scheme for real-time model predictive control

A simple model predictive control (MPC) concept for nonlinear systems under input constraints is considered. The presented algorithm takes advantage of an MPC formulation without terminal constraints in order to solve the optimality conditions by a fixed-point iteration scheme that is easy to implement and of algorithmic simplicity. Sufficient conditions for the contraction of the fixed-point iterations are derived. To allow for a real-time implementation within an MPC scheme, a constant number of fixed-point iterations is used in each sampling step and sufficient conditions for asymptotic stability and incremental reduction of the suboptimality are presented.     

A new stability criterion for fixed-point state–space digital filters using two’s complement arithmetic

A new stability criterion for fixed-point state–space digital filters using two’s complement arithmetic is presented, by estimating the region which the system trajectory will enter and remain in. Numerical examples are given to show the effectiveness of the obtained results.     

Modified criterion for global asymptotic stability of fixed-point state-space digital filters using two’s complement arithmetic

A criterion for the global asymptotic stability of fixed-point state-space digital filters using two’s complement arithmetic is presented. The criterion is a modified form of a well-known criterion due to Mills, Mullis, and Roberts. The criterion is in the form of linear matrix inequality and, hence, computationally tractable. An example shows the effectiveness of the modified criterion.     

接纳控制算法现状分析

3G业务的多样性,QoS的严格性以及无线资源的稀缺性等因素对呼叫接纳控制技术提出了更高的要求。对呼叫接纳控制算法进行概述,讨论了CDMA系统中常用的和移动通信网中具有代表性的呼叫接纳控制算法。     

数控绘图系统中的绘图基本算法

简要介绍了数控绘图系统中不同算法处理系统的反应速度，较详细地讨论了直线与圆算法处理等实际问题。并给出了不同算法相应的处理方法。     

An arithmetic controller design for numerical control

This paper provides an arithmetic controller comprising: an arithmetic logic unit having a plurality of arithmetic instructions, such as ADD (Addition), SUB (Subtraction), MUL (Multiplication), and DIV (Division) instructions. This arithmetic processor was implemented by a cell-based flow and supports the basic mathematical operations, and numerical control.     

基于拥塞的接纳控制算法*

提出一种基于带宽分配的多业务接纳控制算法,依据系统无线拥塞程度的不同相应地采用不同的机制来进行呼叫接入的判决,当系统发生严重拥塞时,拒绝接入所有的呼叫;而在系统发生中等程度的拥塞时,如果新呼叫所隶属的业务类型的数据流在系统中的传输性能已经恶化,拒绝接入此类呼叫;对于未发生拥塞和轻微程度的拥塞这两种情况,根据系统当前的容量限制和预定的带宽分配比例来决定是否接入新的呼叫。用MATLAB仿真确定拥塞程度门限,对算法仿真结果比较显示该算法性能上较优。     

基于接收功率的多业务接纳控制算法

3G业务的多样性、QoS的严格性以及无线资源的稀缺性等因素对呼叫接纳控制技术提出了更高的要求。改进了一种支持多业务的基于接收功率的接纳控制算法。针对原有算法中使用单一判决门限产生高阻塞率的问题,引入可占用总功率的最大比例,根据不同的业务需求,较好地解决了这种问题。此算法可以进行网络优化处理,可以通过挂起或强制拆除不重要的数据业务呼叫,优先接入新到达的切换话音呼叫。     

用继电自整定实现模糊PID智能控制

从提高控制器的智能化水平出发，文中提出了模糊PID自适应控制与继电自整定相结合构成PID双模智能控制器的方法。即用继电自整定法整定出PID控制的初始参数，然后切换到模糊PID自适应控制，完成模糊PID智能控制。将该算法应用于一温控系统中，得到了令人满意的效果。