蚵車安全性之實車測試與電腦模擬分析

Abstract

蚵車為本土產業自主研發及成功製造的產業機具之一，主要作業為運輸採蚵用器具及收成後之帶殼生蚵，因其良好的地形適應能力及不怕海水侵蝕，廣受蚵民之喜愛，也著實減輕了蚵民的運輸作業辛勞。 近年來台灣的蚵養殖工作環境已有很大的改變，由早期簡單之人力、牛力拉車及踩踏車，進步到目前採用動力引擎之車輛，而此種動力車輛其安全性是否無慮，實屬有關蚵民及當地漸增遊客生命安全之重要議題。 本研究先參考農地搬運車性能測定之內文，以實車測試出煞車距離、最小轉彎半徑、靜態翻覆角及平地與坡地試驗等安全性參數，再以電腦輔助工程軟體(ADAMS/Car)為研究工具，利用該軟體建立蚵車之全車運動模型並進行模擬分析，其車輛規格依照實車量測以及彰化王功地區製蚵車工廠提供資料並參與討論所得。實驗中蚵車之最高限速為20 km/h，其配載引擎之馬力為19 hp，載貨台模擬空車及600 kg之載重，並進行不同之虛擬路面，觀察其模擬結果，並與實車測試結果相比較。 實車測試結果顯示打滑率均在1%內，最小轉彎半徑為3.25 m至3.54 m，坡地試驗中蚵車可以停駐於15度斜坡無滑動，這幾項試驗中蚵車性能良好。但蚵車之煞車距離在空車及載重547 kg時，均遠大於農地搬運車性能測定標準，時速(km/h)之15% (m)，靜態翻覆角約在25度左右，也與標準值35度有一段差距，此兩項數據使蚵車之安全性無法符合規定。 電腦模擬結果顯示煞車距離主要由載貨與否影響，載重時煞車距離數據變大，但空車與載貨600 kg時，皆無法符合農地搬運車性能測定之標準，且約為標準值兩倍之多。此外，最小轉彎半徑為6.11 m至6.44 m，雖與實車測試結果有誤差，但轉彎性能仍屬良好。進行坡地模擬時，使搬運車停駐於15度坡地之車體重心維持穩定無滑移。此款採用動力引擎之蚵車，經實車測試與模擬測試之安全性在煞車距離及側向翻覆角數據均無法符合農地搬運車性能測定標準，如需進一步合法化，須加以改良或是另訂蚵車性能測定之標準。

An oyster transporter is a kind of agricultural machinery that has been successfully developed and manufactured by local industry. Its major function is to carry oyster collecting equipment and oysters. Due to its great adaptability to terrain and resistance to sea water corrosion, it is popular with oyster culturists. Moreover, it undoubtedly reduces the hardship of transport tasks. In recent years, there have been dramatic changes to our oyster aquacultural environment, from the early simple manpower and cattle power carts, to the current vehicles using power engines. However, whether these power engine vehicles are really safe has become a significant issue among local culturists and tourists. In this study, first, the safety parameters such as the braking distance, minimum turning radius, static rolling angle, and slope test are tested with vehicle testing with reference to the article “Performance Test of Agricultural Transporter“. Second, this study uses a computer-aided engineering software named ADAMS as a research tool, to build an oyster transporter’s full car kinematic model and to execute simulation analysis. The relevant vehicle specifications and sizes are in accordance with the actual vehicle measurements and information provided by the oyster transporter factory in Wanggong, Changhua. In the simulation, the maximum speed is limited to 20 km/h. The power of the engine is 19 hp. The vehicle’s loading platform simulates a transporter that is empty or grouped into 600 kg. Moreover, various simulated roads are selected. Therefore, the results can be observed after simulation and compared with field tests. Results from field tests show that the slip rate is within 1% and the minimum turning radius is about 3.25 m to 3.54 m. The vehicle can be parked on 15° slopes without slippage. These tests mean the vehicle has good performance. However, the braking distance of the oyster transporter when empty or with a loading of 547 kg is far more than the standard value determined by the “Performance Test of Agricultural Transporter”. The static rolling angle is about 25 degrees, and the standard value is 35 degrees. However, due to these two data, the safety of the oyster transporter cannot measure up to the standard. Computer simulation results show that the braking distance is mainly affected by the loading. The brake distance is larger when vehicle is loaded. However, the braking distances for an empty vehicle or with a loading of 600 kg are unable to meet the requirement of the regulations in the “Performance Test of Agricultural Transporter”, and the results are about twice the standard value. In addition, the minimum turning radius is in the range of 6.11 m to 6.44 m. Although the results have some deviations with vehicle testing results, the turning performance is still good. For the simulation of the slope field test, the center of mass of the vehicle parked on the slope of 15 degrees is stable and has no slippage. In conclusion, the field tests and computer simulation of the safety performance of the oyster transporter cannot meet the requirements of the regulations of the “Performance Test of Agricultural Transporter”. For this vehicle to be legalized, it should be improved or other regulations should be set up to test the performance of oyster transporters.