運用粒子群最佳化法於手輪馬達式電動輪椅用交互耦合轉速比控制器設計

Cross-coupling control with particle swarm optimization for a powered wheelchair driven by rim motors

陳柏叡(Po-Ray Chen)

指導教授 ： 陽毅平

國立臺灣大學/工學院/機械工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.03108

摘要

本文之研究目的在於建立完整的手輪馬達式電動輪椅控制器，並運用粒子群最佳化於電動輪椅控制器PID參數的調整，使電動輪椅控制器得以符合控制性能的設計要求。文中先介紹手輪馬達式電動輪椅動力鏈系統的組成，動力鏈系統將手輪馬達、馬達驅動控制器、鋰鐵電池與整合式電磁煞車整合於一車輪內，而成為一動力輪，如此則僅需要一普通輪椅車架搭配兩個動力輪，即可結合成一手輪馬達式電動輪椅，再介紹無刷直流馬達運轉原理與驅動原理，使用方波驅動令馬達起步再搭配簡化弦波電流控制，以驅動控制手輪馬達式電動輪椅。
手輪馬達式電動輪椅控制器的控制目標有二，一為維持雙輪的命令轉速比，以符合使用者期待的轉動方向；二為控制單手輪馬達的轉速，以符合使用者期待的輪椅前進速度。手輪馬達式電動輪椅控制器可以分為兩個部分，第一部分為交互補償雙輪轉速的交互耦合轉速比控制器，其控制目標即是使輪椅克服雙輪不同的馬達特性或路況條件，以達到轉速比的穩定控制，使電動輪椅有正確的轉動方向；第二部分為單輪的閉迴路轉速控制器，藉由轉速閉迴路的回饋補償來實現穩定的轉速控制，以符合使用者期待的電動輪椅前進速度。
在電動輪椅控制器PID參數的調整上，本文運用粒子群最佳化法於手輪馬達式電動輪椅控制器的調整。由於PID控制器性能的好與壞，取決於是否能找到符合控制需求的PID控制器參數解，而傳統的PID控制參數調整方法，調整的過程通常較為繁瑣且控制器參數不易達到最佳化，因此本文藉由運用粒子群最佳化於控制器PID參數的調整，並將粒子群最佳化設計出的PID控制器，與藉由Ziegler-Nichols方法所設計出的PID控制器，對兩控制器進行模擬與實測的比較討論，以驗證基於粒子群最佳化控制器設計的控制效果，而經模擬與多次實測的比較後，可以證實運用粒子群最佳化法設計的PID控制器，有較佳於Ziegler-Nichols方法的控制效能。

關鍵字

粒子群最佳化法 ； 交互耦合轉速比控制 ； 閉迴路轉速控制 ； 手輪馬達 ； 電動輪椅 ； 動力鏈系統

並列摘要

This paper establishes a comprehensive rim-motor-powered wheelchair controller. We will accomplish this by manipulating the particle swarm optimization (PSO) when adjusting the PID parameters, making the controller’s performance conform to design requirements. This paper begins by describing the rim-motor-powered wheelchair’s power chain system, which integrates the rim motor, motor driver, motor controller, lithium ion battery, and electromagnetic brake into a powered wheel; this allows for an ordinary wheelchair frame and two powered wheels to be combined into a rim-motor-powered wheelchair. Next, the paper defines the Brushless DC electric motor’s operation principle and driving principle, which uses a square wave to start the rim motor and a simplified sinusoidal current control to drive the rim-motor-powered wheelchair.
There are two objectives for the rim-motor-powered wheelchair controller: 1) maintain command of the two motors’ speed ratio to fit the direction of movement expected by the user, and 2) achieve the expected forward velocity for the wheelchair. The controller itself can be divided into two mechanisms. The first is the optimal cross-coupling speed ratio controller, which helps the wheelchair overcome the difference between the two motors’ characteristics in road conditions, achieves a stable speed ratio, and maintains the correct rotational direction of the powered wheelchair. The second is a single-rim motor with a closed-loop speed controller; this achieves a stable speed via closed-loop feedback compensation, which fits the wheelchair’s expected forward velocity. This study uses the PSO method to adjust the PID parameters. The PID controller’s performance depends on whether its parameter solution fits the control requirements; however, the process for a traditional PID control parameter adjustment method is usually more complicated, and it is unlikely that the controller’s parameters will be optimal. Hence, this article compares the PID controller designed using the PSO method with the PID controller designed using the Ziegler-Nichols method. By comparing the simulations and results from multiple experiments, we can confirm that the PID controller designed using the PSO method performs better than the controller designed using the Ziegler-Nichols method.

並列關鍵字

Particle swarm optimization ； optimal cross-coupling speed ratio control ； closed-loop speed control ； rim motor ； powered wheelchair ； power chain system

參考文獻

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