Ping-Min Hsu

Realization of Anti-Lock Braking Strategy for Electric Scooters

This research studies a novel method of realizing a nonmechanical antilock braking system (ABS) controller for electric scooters (ESs) based on regenerative, kinetic, and short-circuit braking mechanisms. In which, a boundary layer speed control is proposed for a guarantee of the optimal slip ratio between tires and road surface. The antilock braking controller, combined with this controller, drives a low-side driving circuit to induce either an open-circuit or a short-circuit loop on the motor stators coil to a load; it thus produces braking actions analogous to those in the conventional ABS control. The proposed ABS controller is practically realized. Improvement of the braking performance for the ABS action is further addressed via real-world experiments.

Time-delay compensation for time-varying delayed systems using extended network disturbance

Design of a time-delay compensation based on the extended network disturbance (END) with disturbance observers for nonlinear systems under time-varying delays is presented. The distinguished advantage of the approach is that the time-delay behavior in systems can be viewed as a result of including END into a system without delays. This allows the proposed method to work without any delay estimation. In addition, we apply a proportional, multiple-integral and derivative observer to estimate the network disturbance. The proposed strategy is verified under the congestion control design for a local wired network system with time-varying delayed states and inputs.

Active Queue Management within Large-Scale Wired Networks

Signal transmission control protocol sources with the objective of managing queue utilization and delay is actually a feedback control problem in active queue management (AQM) core routers. This paper extends AQM control design for single network systems to large-scale wired network systems with time delays at each communication channel. A system model consisted of several local networks is first constructed. The stability condition guaranteeing overall stability is subsequently derived using Lyapunov stability theory. The results developed have been successfully verified on a network simulator.

Time-delay compensation using nonlinear extended network disturbance

This paper investigates control design for time-delay compensation for the time-varying delayed systems, especially, the network transmission dynamics. We propose an idea of virtual disturbance, named nonlinear extended network disturbance (NEND), such that the delayed behavior of the considered model is treated as the effect of injecting NEND into the system. The larger the magnitude of NEND means that the system exhibits the greater time delay. In other words, performing NEND compensation achieves time-delay compensation. This NEND compensation is achieved by introducing the control scheme with an observer for NEND estimation. The proposed design has been verified in the wired network.

Congestion control for local wireless sensor network using time-delay compensator

This paper concerns the congestion control problem for local wireless sensor networks. A novel design strategy for time-delay compensation without the consideration of delay estimation is proposed. With the aid of this method, a time-varying delay can be compensated and a congestion controller combined with this compensator is designed. The approach is fully verified by the network simulator NS2.

A New Algorithm to Achieve Bandwidth Fairness: Power-Red

Its becoming one of the major research issues that how to handle data congestion and avoidance of that on the network in an efficient way has become a crucial issue because of bursting data traffic. There are a variety of congestion control strategies have been proposed to avoid congestion at the bottleneck nodes. Among which, random-early-detection (RED) is widely applied in IP network nowadays. It provides high bandwidth (BW) utilisation by dropping packets randomly selected from the queue. These dropped packets will then serve as signals that notify their transmission ends to decrease the sending rate, preventing congestion from happening. Unfortunately, RED algorithm provides little protection against aggressive flows, such as flows with large packets, or congestion insensitive flows. As a result, it is easy for these flows to consume most of the bandwidth, causing unfair bandwidth sharing. In this paper, we propose a new algorithm, named as Power-RED, which aims to achieve BW fairness. Power-RED keeps a throughput statistics, and adjusts packet drop probabilities according to power law when a network tends to become congested. Its goal is to maintain a fair bandwidth share among all incoming connections. Power-RED monitors throughput of active flows, and adjusts drop probabilities individually according to their throughputs for the purpose of BW fairness. The extensive real-world experiments in a PC networks shows that Power-RED can effectively guarantee fairness not only in packet numbers but also in their sizes.

Active Queue Management in Wireless Networks by Using Nonlinear Extended Network Disturbance

Abstract This paper studies congestion control in local wireless networks supporting transmission control protocol (TCP) under random early detection (RED). In general, congestion delays may cause instability of the routers running active queue management (AQM) protocols such as RED. Moreover, its management efficiency could be reduced by serious queue oscillation. To improve these two drawbacks, we propose a robust congestion controller focusing on the queue oscillation suppression and time-delay compensation based on an idea of nonlinear extended network disturbance (NEND). The time-delay compensation is further performed via the NEND rejection. Furthermore, the proposed strategy has been validated on NS2 showing their applicability.

Noise rejection of nonlinear systems with measurement noises

This paper investigates control design focusing on noise rejection of disturbed nonlinear systems. The disturbance rejection scheme is proposed with a noise estimator, constructed upon a concern-most disturbances can be approximately described by a differential equation. A controller is further proposed to stabilize the considered system and simultaneously fulfill the disturbance compensation by using the disturbance estimator. Superiority of our strategy is addressed by means of a case study.

Point stabilization for autonomous lawnmower using backstepping adaptive control

This paper studied the point stabilization problem for a constrained autonomous lawnmower. A constrained kinetic model is established first. The authors proposed a backstepping adaptive controller to solve the stabilizing control design problem. The proposed approach has been numerically verified.

Congestion control for large-scale wired network using time-delay compensator

This paper concerns the congestion control problem for large-scale wired networks. A new model describing for large-scale wired networks is proposed. A compensation strategy is derived to deal with the time-delay problem. On the basis of the strategy, a network controller is established to accomplish the congestion control. The approach is experimentally verified on the network simulator (NS2).