- 學位論文
手輪馬達電動輪椅之霍爾感測器失效控制策略
Hall Sensor Fault Tolerant Control Strategy for a Powered Wheelchair Driven by Rim Motors
摘要
本文的研究目的在於開發手輪馬達電動輪椅之霍爾感測器失效偵測系統，並搭配馬達轉子角度之估算系統，並將其整合成手輪馬達電動輪椅之霍爾感測器失效控制策略，文中先介紹手輪馬達電動輪椅之動力系統手輪馬達及機械式煞車模組，機械式煞車模組主要由機械式煞車系統及手持釋放機構組合而成，機械式煞車系統採用咬接離合器配合彈簧與電磁閥，此煞車原理為利用彈簧力將咬接離合器壓緊，使輪子停止轉動達到煞車效果，並藉由控制電磁閥抵抗彈簧力將煞車釋放，在電力系統發生異常無法使用電磁閥釋放煞車時，可以使用手持式釋放機構將煞車釋放，轉動三爪型操作介面藉由螺紋將轉動運動轉為直線運動，推動咬接離合器使煞車釋放。 本研究之手輪馬達的主要架構為直流無刷馬達，搭配三顆霍爾感測器做為提供轉子角度的資訊，此種位置感測器有成本低且體積小之優點，本文觀察三顆霍爾感測器在馬達轉動時所輸出的訊號，藉此建立霍爾感測器失效偵測系統，當訊號出現異常時，將會針對此異常訊號進行判斷，選出正常運作之霍爾感測器，並用其進行單一霍爾感測器轉子角度估測，如判斷無正常運作之霍爾感測器則進行無感測器角度估測，最後再將轉子角度資訊輸出至下控制器以驅動手輪馬達，使電動輪椅得以運行。 本研究之霍爾感測器失效控制策略，使手輪馬達電動輪椅在行駛過程中免於因霍爾感測器損壞或訊號異常而導致輪椅失控的情形，可以有效的防止或降低危險，並且搭配安全性機械煞車，確保輪椅在停止時不會因為地形因素而任意移動，如此一來可以加強此電動輪椅之安全性。
並列摘要
The purpose of this paper is to discuss the development of a powered wheelchair driven by a rim motor of the Hall sensor failure detection system while matching it with a rotor angle estimation system, and to integrate it into the Hall sensor fault tolerant control strategy for a powered wheelchair driven by rim motors. This paper will firstly introduce the power system of the powered wheelchair driven by rim motors and the mechanical brake module. The mechanical brake module is primarily composed of a mechanical brake system and a handheld release brake system, as well as adding the spring and the Solenoid valve together by using the dog clutch. The principle of this brake system is to utilize the Spring force to press the dog clutch tightly, making the wheel stop rotating in order to achieve the brake effect, and also to release the brake by controlling the Solenoid valve against the Spring force. When anomalies occur in the power system and the system cannot release the brake by the Solenoid valve, it is still possible to release the brake by the handheld release brake system, rotating the three-clawed operation interface in order to make the handheld release brake system into linear motion due to the screw thread, then pushing the dog clutch to release the brake. The main structure of the rim motor in this study is a brushless DC motor. It provides information of the rotor angle by combining with three hall sensors. These position sensors are advantageous for their low cost and small size. By observing the signal from these three Hall sensors when the motor rotates, this study establishes the fault tolerant control system of Hall sensor. When anomalies occur from the signal, this study will distinguish the abnormal signal, choosing the Hall sensor which is in good condition. It will operating the rotor angle estimation of the single Hall sensor by using the Hall sensor which is in good condition. If there is no well- working Hall sensor to be distinguished, it will operate the estimation of sensorless angle, and output the information of rotor angle into the under controller to drive the rim motor, making sure that the powered wheelchair is available. The Hall Sensor Failure control strategy we discussed in this paper makes the powered wheelchair driven by the rim motor remain in control due to Hall sensor damages or abnormal signals while driving. It can effectively prevent or reduce dangers. Additionally, as it is equipped with a mechanical safety brake, the strategy ensures that wheelchair ignores different terrain factors and stays put instead of moving in arbitrary directions when it stops. As a result, it strengthens the safety of the powered wheelchair.